i hspa dimensioning-and_planning_customer_doc (1)

Planning and Dimensioning I-HSPA (Draft for I-HSPA Release 1Trial)

DN70387977Issue 1-1 en draft06/03/2008

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2 (151) # Nokia Siemens Networks DN70387977Issue 1-1 en draft

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Planning and Dimensioning I-HSPA (Draft for I-HSPA Release 1 Trial)

Contents

Contents 3

Summary of changes 5

1 Introduction to dimensioning and planning I-HSPA 7

2 I-HSPA impact on dimensioning and planning 9

3 Dimensioning I-HSPA 11

4 Dimensioning Air interface 154.1 Introduction to dimensioning Air Interface 154.2 Traffic and service definition 184.2.1 Overview of traffic and service definition 184.2.2 VoIP dimensioning 204.2.3 Data traffic dimensioning 214.3 Coverage dimensioning 234.3.1 Overview of coverage dimensioning 234.3.2 HSDPA link budget 234.3.3 HSDPA associated UL DPCH link budget 314.3.4 HSUPA link budget 364.3.5 Cell range and coverage 414.4 Capacity dimensioning 434.4.1 Overview of capacity dimensioning 434.4.2 Downlink capacity 454.4.3 Uplink capacity 48

5 Dimensioning hardware 535.1 Introduction to dimensioning Node B 535.2 Node B dimensioning 545.3 I-HSPA Adapter dimensioning 59

6 Planning Air interface 616.1 Introduction to planning Air interface 616.2 Planning Air interface 646.3 Planning coverage 696.4 Planning capacity 776.5 Downlink capacity planning 816.6 Uplink capacity planning 836.7 Planning configuration 856.8 Planning parameters for radio network 886.9 Mobility scenarios 936.10 CS interworking 966.11 URA planning and paging 966.12 LAC and RAC planning 996.13 HSDPA features and parameters 1006.13.1 HSDPA resource management 1006.13.2 Maximum bit rate of HS-DSCH MAC-d flow 101

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Contents

6.13.3 HSDPA mobility handling 1016.14 HSUPA features and parameters 103

7 Dimensioning Adapter and interface 1077.1 Hardware description and performance 1077.1.1 Capacity and performance 1097.1.2 Capacity of the I-HSPA Adapter 1117.2 Traffic model 1127.2.1 Subscriber traffic model 1127.2.2 Application model 1137.3 Feature description 1147.3.1 QoS 1147.3.2 Mobility 1177.3.3 One Tunnel Approach 1247.4 Traffic modelling 1277.4.1 Dimensioning the Adapter 1317.4.2 Dimensioning the Interface 131

8 Planning Adapter and interface 1338.1 I-HSPA Adapter and interface planning 1338.2 Planning steps 1348.2.1 Basic planning information 1358.2.2 Traffic modelling 1368.2.3 Additional traffic 1398.2.3.1 Overhead 1398.2.3.2 Control plane traffic 1418.2.4 Dimensioning 1418.2.4.1 Elastic traffic (non Real Time) dimensioning algorithm 1438.2.4.2 Streaming (Real Time) traffic dimensioning algorithm 147


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Summary of changes

Changes between document issues are cumulative. Therefore, the latestdocument issue contains all changes made to previous issues.

The changes between document issues are cumulative. Therefore, thelatest document issue contains all changes made to the previous issue.

Changes between issues 1-0 and 1-1

Sections Dimensioning Adapter and interface and Planning Adapter andinterface have been added.

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Summary of changes


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1 Introduction to dimensioning andplanning I-HSPA

The purpose of this document is to describe the dimensioning andplanning process for I-HSPA.

Introducing I-HSPA in the radio access network (RAN) brings severalchanges to the dimensioning and planning process, when compared to anormal WCDMA radio access network (RAN). In the documentationcovering the dimensioning and planning of I-HSPA network, the term'traditional' WCDMA RAN is used for referring to WCDMA RAN without I-HSPA Adapter.

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Introduction to dimensioning and planning I-HSPA


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2 I-HSPA impact on dimensioning andplanning

The introduction of I-HSPA in the radio access network (RAN) brings newaspects to both dimensioning and planning. These differences areintroduced in the list below.

The main differences related to dimensioning I-HSPA are listed below.

Architecture:

. No stand-alone RNC, instead I-HSPA Adapter is integrated to NodeB.

. Iub only as an internal interface in NodeB.

. iNB is connected to SGSN through IuPS control plane.

. iNB is connected to GGSN for user plane (One Tunnel Solution).

Services:

. Packet service only (UL DCH+HSDPA or HSUPA+HSDPA).

. CS services are handed over to the traditional WCDMA radionetwork.

. No DCH possible in downlink, with the exception of SRB.

. Speech service through VoIP.

. Mobile terminals from 3GPP Release 5 onwards are supported.

Functionality:

. I-HSPA is a fully mobile solution, supporting three kinds of mobility:. Intra-system hand-over within I-HSPA.. Inter-system hand-over between I-HSPA and traditional

WCDMA/HSDPA.

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I-HSPA impact on dimensioning and planning

. In HSUPA, SHO is not available for user plane, as SHO over Iur isnot possible. Softer HO and control plane SHO are supported.

The main differences related to planning I-HSPA are listed below.

Configuration management:

. Additional parameters, but less than in traditional WCDMA RAN.

. NetACT and SGSN/GGSN need to handle large amount of 'RNCs',that is, I-HSPA Adapters

Mobility management:

. Cell reselection planning between traditional WCDMA RAN or GSMand I-HSPA.

. Handovers and neighbour planning between traditional WCDMARAN or GSM and I-HSPA.

. Support for URA.


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3 Dimensioning I-HSPAPurpose

Dimensioning is the initial phase of network planning. Duringdimensioning, the first configuration estimates and requirements forcoverage, capacity and quality of service are planned. The approximatenumber of necessary base station sites and base stations, the averagevalues for the power budget, cell size, capacity, and initial networkconfiguration are estimated at this phase. The capacity requirements andthe overall quality of service targets determine the selection of the RANtransport network capacity and transport interfaces used. Operators withexisting network can use dimensioning to estimate the service capability ofthe existing network, while in case of site reuse existing locations can beused to determine what can be achieved without new sites.

Note that in the dimensioning phase, only average values for the networkcan be calculated. More exact values for individual sites are calculated inthe actual planning phase.

Before you start

Check:

. Traffic expectations. An accurate traffic forecast is important innetwork dimensioning. Deviations must be taken into account incapacity planning.

. Population density in the area. Specify areas of population thatshould be covered in each phase of roll-out.

. Location probability. Specify system area availability indoors/outdoors.

. Regulations, for example, spectrum allocations and transmit powerlimitations.

. Specific system performance parameters.

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Dimensioning I-HSPA

. VoIP and CS speech service strategy.

. Mobility strategy.

The basic parameters for dimensioning are the following:

. Quality of service in terms of call blocking and coverage probabilityper service

. Estimated traffic requirements for packet data users and possibleVoIP users

. Development of service requirements, the service profile as afunction of time

. Radio network area information: the total area, division into differentsub-areas or area types, and the user distribution for each sub-area

Summary

Radio network dimensioning activities include coverage, capacity, andquality of service analysis. The results of this analysis are the main inputfor the dimensioning of the transport network.

Steps

1. Estimate coverage.

a. The coverage efficiency of I-HSPA is defined by the averagecoverage area per site, for a predefined propagationenvironment, and supported traffic density.

b. Check the size of the area.

c. Take the area type into account and consider the suitability ofthe propagation model.

d. Different area types are, for example, dense urban, urban,suburban, and rural. There can also be special areas within anarea, for example an airport or an industrial area.

2. Estimate capacity.

a. Check the frequency range and the amount of spectrum thatcan be used.

b. Estimate the amount of supported traffic per base station site.

3. Estimate quality of service.


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Consider blocking and location probability. Typical values are 5%and 95% respectively. Location probability varies for differentservices according to the required data rates. For example, thelocation probability for a service that requires faster data rates maybe smaller.

Expected outcome

A rough estimate of the required sites and network elements:

. base stations

. base station configurations

and requirements and strategy for:

. coverage

. quality

. capacity

. transport network

per service based on the given input parameters.

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Dimensioning I-HSPA


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4 Dimensioning Air interface

4.1 Introduction to dimensioning Air Interface

Air interface dimensioning is based on the predicted subscriber density,subscriber traffic profiles, propagation environment, and service qualitytargets. With I-HSPA, the dimensioning has to be done iteratively,considering the Air interface load and cell range coupling. Figure Basestation dimensioning flow presents the iteration steps. The calculations arebased on basic WCDMA formulas, propagation models, and statisticalanalysis.

Figure 1. Base station dimensioning flow

CapacityRequirement

Link BudgetCalculation

Area typesAntenna gains

Subscribers/kmTraffic/Subscribe

2

Load FactorCalculation

EquipmentRequirement

Cell RangeCalculation

Coverage targetsFading margins

Allowed blocking/queuing

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Dimensioning Air interface

In I-HSPA, the architecture and lack of CS services leads to a dedicatedcarrier dimensioning scenario. A dedicated carrier scenario means that inAir interface dimensioning, downlink Air interface capacity is available forHSDPA, and uplink HSUPA has most of the capacity, only lowered byHSDPA associated UL DPCH.

Figure I-HSPA Air interface dimensioning shows the I-HSPA dimensioningprocess.

Figure 2. I-HSPA Air interface dimensioning

As Figure I-HSPA Air interface dimensioning shows, I-HSPA Air interfacedimensioning is similar to dedicated carrier dimensioning.

Differences exist in the Air interface dimensioning process betweentraditional WCDMA RAN and I-HSPA. The list below introduces thedifferences.

The following differences exist in services:

. CS services are handed over to either GSM or WCDMA.

. No downlink PS DCH services.

I-HSPA Air interface dimensioning

Coverage dimensioningselection:

- Link Budget R99(based on service)- Link Budget HSDPA(based on cell edgethroughput)- Link Budget HSUPA(based on cell edgethroughput)- Output # of coverage sites

R99 capacitydimensioning

Resultevaluation

CECalculation

HSDPA capacitydimensioning

HSUPA capacitydimensioning

Iu-PS/GNDimensioning

I-HSPAAdapter

Dimensioning

Additionalcapacity Node Bs

Dimensioning inputs and requirements

Coverage dimensioning Capacity dimensioning

Input: availableHSUPA capacity

Output: HSUPAthroughput

OK

Not OK

UL/DL Load,Node B DL power

Output: HSDPAthroughput

Input: availableHSDPA capacity

# ofNode Bs

(coverage +capacity)

I-HSPA CNDimensioning


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. In uplink:HSDPA associated UL DPCH service (16, 64, 128, 384)and HSUPA are supported.

. VoIP services are supported, no CS speech available.

The following differences exist in link budget:

. I-HSPA can be implemented with and without SHO. SHO requiresIur interface to be present.

. In HSUPA without SHO, there is a reduced soft handover gain to0.5dB in uplink due to the lack of SHO in user plane, this limitation isvalid only for Release 1. HSDPA associated UL DPCH overhead ofHS-DPCCH is valued with no SHO, thus giving 1.5 dB advantage in64 kbps service.

. With Iur interface present, SHO is implemented using the normalSHO gain for DCH traffic. HSUPA does not support user plane SHOover Iur.

The following differences exist in capacity:

. In uplink: Only HSDPA associated UL DPCH traffic load has to betaken into account when estimating HSUPA capacity.

. In downlink: as there is no DCH traffic, the whole capacity isdedicated to HSDPA.

I-HSPA Air interface dimensioning is simplified by the fact that estimatingthe impact of R99 traffic is not a high priority. As available power indownlink can be shared among HSDPA users, no capacity fluctuationtakes place due to higher priority R99 traffic.

I-HSPA Air interface dimensioning consists of dimensioning inputs,coverage and capacity calculation. The dimensioning process provides theneeded amount of I-HSPA base stations.

The required dimensioning information is outlined in the list below.

1. Dimensioning inputs.. Amount of subscribers.. Area size, clutter type and factors.. Simultaneous VoIP users, call duration, BH usage,

compression usage.. Data services, data volume, overbooking, utilization, activity.

2. Coverage calculation.

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Coverage calculations can be based on DPCH UL services, HSDPAor HSUPA with defined cell edge throughput.. DPCH UL

Coverage is defined for 16/64/128/384 kbps (16/64 kbps areused to support VoIP).

. HSDPA

Coverage is calculated for defined cell edge throughput.. HSUPA

Coverage is calculated for defined cell edge throughput.

3. Capacity dimensioning.. HSDPA utilizes all DL power that is left from CCH (noticing

also power control overhead).. R99 UL load is calculated from the defined traffic mix of

associated RAB for HSDPA.. For HSUPA, the capacity is calculated by deducting DPCH UL

(in case DPCH UL associated RAB is used, which can be 16/64/128/384 kbps) load from the value of planned maximum ULload.

4. Verification of capacity and the need for additional site if therequirements are not fulfilled.

5. CE calculation.. HSDPA

CE usage depends on parameters such as the number ofcodes (5/10/15), shared scheduler or cell specific scheduler.

. HSUPA

CE usage depends on the amount of simultaneous users, aswell as on the throughput requirement at base station level.

. CE for UL DPCH is based on user-associated bearerutilization.

4.2 Traffic and service definition

4.2.1 Overview of traffic and service definition

There are differences between I-HSPA with normal HSPA due to I-HSPAspecific implementation.

The main differences in traffic and service definition are listed below.


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. I-HSPA hands CS services over to GSM and WCDMA.

. Voice service is VoIP.

. Dimensioning involves DSL-type traffic modeling.

. Equal priority for all services through flat-rate modeling.

I-HSPA deployment scenario influences traffic definition. I-HSPA can bedeployed as a capacity expansion for existing WCDMA operators, or as anew solution for greenfield operators.

. Greenfield operator:. High focus on VoIP traffic, as no underlaying network with CS

services exists.. Focus on packet traffic trends and growth estimation.

. Existing operator:. Lower focus on VoIP, as an existing network carries the voice

services.. Customer can make packet data trends available.. I-HSPA may provide a data layer solution.

Packet-oriented service focus leads to different QoS-related inputs forcapacity dimensioning.

The following input is required for VoIP dimensioning:

. Number of VoIP subscribers.

. Number of VoIP calls and call duration.

. Delay assumptions (VoIP can tolerate 20 to 80 ms delay).

For more information on VoIP dimensioning, see VoIP dimensioning.

The following input is required for data traffic dimensioning:

. Peak User Data Rate subscription parameter (for example, 512/128kbps DL/UL).

. Typical values for DL data rates are 128K, 256K, 384K, 512K, and1M.

. Overbooking Factor [4-50]. Overbooking factor defines the numberof simultaneous users that share the same capacity resources. Anoverbooking factor of 4 can apply to very high business subscription,and up to a factor of 50 for very low domestic subscriptions.

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For example: 512 kbps can be shared by 20 users with an averageof 25 kbps (overbooking factor 20).

For more information on data traffic dimensioning, see Data trafficdimensioning.

4.2.2 VoIP dimensioning

In I-HSPA, the available voice service is VoIP. CS traffic is handed over toGSM or WCDMA.

I-HSPA release 1 does not support Robust Header Compression (ROHC).Traffic capacity estimations for I-HSPA release 1 have to be made fortraffic without ROHC.

HSDPA code multiplexing (CM) enables more than 3 UEs to use the same2 ms TTI. Since VoIP packets arrive every 20 ms and if no CM is used, themaximum number of VoIP users that fit on the shared HS-DSCH channelin cell downlink is 10. Using multiple HS-SCCH channels and allowingextra delay for packing multiple VoIP packets from the same UE into asingle TTI makes it possible to increase the number of users on the sharedchannel.

In I-HSPA release 1, the limitation in maximum amount of users comesfrom a system limitation, as HSDPA users are limited to either 16/48 usersper Node B or cell. For 48 users, CM is required to enable 3 simultaneoususers in the same TTI. In HSUPA, the system limitation is set to 20 usersper cell and 24 per Node B.

Example 1 shows an example of VoIP traffic dimensioning.

Example

In HSUPA, the average data rate is 50% due to voice activity detection inAMR codec. In this case, VoIP throughput without ROCH is 14.7 kbps(50% of 29.4 kbps).

The following values:

. Number of Node Bs = 50.

. Number of VoIP users during Busy Hour (BH) = 20 000.

. Average call duration in BH = 90 seconds.

. Average number of calls in BH = 1.4.


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Result in:

. Total calls duration during BH = 2520000 sec corresponds onaverage of 700 calls per second.

. Total calls per Node B per second = 14, per sector = 4.7.

. Total VoIP call load per sector = 68,6 kbps.

4.2.3 Data traffic dimensioning

Data traffic is common for I-HSPA. This requires special consideration forissues such as overbooking factor.

DSL service throughputs (UL/DL) can be, for example, 64/128, 128/384,256/512, 384/1M or up to 2M/4M. Higher throughputs are not achievable atcell edge due to high own-to-other cell interference.

Overbooking factor is used to estimate how much the user loads thesystem at peak moment. Commonly values of 10, 15, 20 or even 40 areused as the overbooking factor. This means that 1M load in case of anoverbooking factor of 20 would mean 1 Mbps / 20 = 50 kbps forsimultaneous users. The overbooking factor can differ according to thesubscriber profile, such as business, high and medium private customer.This categorization influences also traffic consumption.

There are several ways of calculating the capacity by packet data.Example 1 shows examples of packet data capacity calculation.

Example

Scenario 1:

. BH DSL users = 2 000.

. Average traffic per user per BH = 5 MB.

. Total traffic = 10 GB.

. Number of Node Bs = 50.

. Total load per Node B = 200 MB.

. Total load per sector per BH = 67 MB --> 67*1024*8/3600 = 152.5kbps.

Scenario 2:

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. 10 simultaneous 256/512 users per cell with overbooking factor of20.

. Load UL = 12.8 * 10 = 128 kbps.

. Load DL = 25.6 * 10 = 256 kbps.

Figures Capacity dimensioning with 1+1+1 HSDPA and Broadbandconnection over HSPA with 400 broadband subscribers per 1+1+1 BTSshow typical traffic estimation examples and how basic estimation can bemade for packet services as broadband services.

Figure 3. Capacity dimensioning with 1+1+1 HSDPA

Figure 4. Broadband connection over HSPA with 400 broadband subscribersper 1+1+1 BTS

1 25 kbps on average is equal to 0.5 Mbps with overbooking factor of 20.

2 3 * 2.5 Mbps / 8192 * 3600 * 0.8 / 0.2 * 30 = 400 GB / site / month.

Sitecapacity

Busy hourutilization

Traffic persub

Max subs per site

Sitecapacity

Overbookingratio

Peak userdata rate

Max subs per site

= 400GB/site*75%/1GB/sub = 300 subs/site = 3 2.5Mbps/site*40%/1Mbps = 300 subs/sitex

Data volume based dimensioning Contention ratio based dimensioning

400 GB/month 75% 1 GB/sub 3 2.5 Mbps/sitex 40 1 Mbps

Sitecapacity

Averageuser rate

Max subs per site

= 400GB/site2/1GB/sub= 400 subs/site

= 3 2.5Mbps/site*20kbpsx

Data volume baseddimensioning

Sitecapacity

Max subs per site

Traffic persub

= 375 subs/site

Contention ratiobased dimensioning

400 GB/month 1 GB/sub 3 2.5 Mbps/site3x 20 kbps1


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3 Systems simulation shows that dedicated HSDPA can deliver 2.5 Mbpsper cell.

4.3 Coverage dimensioning

4.3.1 Overview of coverage dimensioning

In coverage dimensioning, the target for HSDPA and HSUPA is the celledge throughput, which is utilized with planning parameters to get the cellrange. The achieved cell edge throughput depends on the amount ofpower allocated for HSDPA. In I-HSPA, the capacity of the carrier isallocated fully to HSDPA in downlink. In uplink the available load is sharedbetween HSUPA and HSDPA associated UL DPCH. The coveragedimensioning is made by using link budgets.

Coverage dimensioning can be based on the following link budgets:

. HSDPA associated UL DPCH service link budget (16, 64, 128 or 384kbps).

For more information on HSDPA associated UL DPCH service linkbudget, see HSDPA associated UL DPCH link budget.

. HSDPA link budget with selected cell edge throughput.

For more information on HSDPA link budget, see HSDPA linkbudget.

. HSUPA link budget with selected cell edge throughput.

For more information on HSUPA link budget, see HSUPA linkbudget.

Coverage dimensioning provides the following information:

. The number of sites needed to cover certain area.

. Cell range and site coverage area, based on different cell edgethroughput or utilized associated UL service bit rate.

4.3.2 HSDPA link budget

The following describes coverage dimensioning based on HSDPA linkbudget.

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HSDPA consists of three main link budgets:

. HS-PDSCH, PS data.

. HS-SCCH, control.

. DPCH, signalling.

HS-PDSCH link budget is used for coverage dimensioning for I-HSPA.Table HSDPA downlink link budget for HS-PDSCH shows the downlinkbudget for HS-PDSCH.

Table 1. HSDPA downlink link budget for HS-PDSCH

Downlink Service

Cell Edge Throughput 384

Channel HS-PDSCH

Service PS Data

Service Rate (kbps) 384

Transmitter - Node B

Max Tx Power (dBm) 37.4

Cable Loss (dBi) 0.5

MHA Insertion Loss 0.0

Tx Antenna Gain (dBi) 18

EIRP (dBm) 54.9

Receiver - Handset

Handset Noise Figure (dB) 7

Thermal Noise (dBm) -108

Downlink Load (%) 80

Interference Margin (dB) 7.0

Interference Floor (dBm) -94.0

SINR Requirement (dB) 4.5

Spreading Gain (dB) 12.0

Receiver Sensitivity (dBm) -101.5

Rx Antenna Gain (dBi) 2

Body Loss (dB) 0

DL Fast Fade Margin (dB) 0

DL Soft Handover Gain (dB) 0


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Table 1. HSDPA downlink link budget for HS-PDSCH (cont.)

Downlink Service

Gain against shadowing (dB) 2.5

Building Penetration Loss(dB)

12

Indoor Location Prob. (%) 90

Indoor Standard Dev. (dB) 10

Shadowing margin (dB) 7.8

Isotropic Power Required(dB)

-86.3

Allowed Prop. Loss (dB) 141.2

HSDPA link budget consists of selecting cell edge throughput andestimating available HSDPA power. HSDPA power, signalling, control andpower control headroom are taken into account in calculating link budget.

There are no major differences between I-HSPA downlink and the normalHSDPA link budget from the viewpoint of coverage dimensioning. BodyLoss is an exception that requires consideration in I-HSPA coveragedimensioning, as the voice service is handled over HSPA. This is casespecific and related to user equipment location.

HS-SCCH link budget is needed in I-HSPA to estimate the control channelpower. The available power remaining from control channels (HS-SCCHand SRB) is then allocated for HSDPA. In I-HSPA, there is no need toestimate how much power is needed for R99 traffic, as I-HSPA does notcarry R99 traffic in DL.

Example

The available power for HSDPA in DL can be estimated in the followingway:

. PtxMAX, which is a Node B with maximum power (for example, 20W)

. Estimating CCCH power usage (for example, 20% = 4 W)

. Estimating HSDPA control CH power at cell edge can be from 0.5 Wto 1.6 W, depending on the assumed number of users in a cell.

. HSDPA power available is calculated just to include rest of thepower:

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PHSDPA_tx = PWBTS_max - CCCH_power - HSDPA_control

20% for CCCH power (4 W) and 9% additional power for HS-SCCH (1.2W), and the associated DPCH power (0.6 W) results in 14.2 W of poweravailable for HSDPA users. With I-HSPA, 14.2 W of power is available forone or more users.

HSDPA throughput depends directly on the radio channel conditions.These conditions change rapidly due to fast fading of the radio channel.BTS is able to change the link adaptation for each 2ms TTI based on thechannel measurements. This means that the achieved throughput isdifferent in every TTI. The average throughput in a certain location can beestimated if the average SINR (Signal to Interference + Noise Ratio) isknown. Commonly simulation results are used for estimating the averageSINR.

Figure Throughput and SINR comparison shows SINR and throughputusing different codes.


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Figure 5. Throughput and SINR comparison

As shown in Figure Throughput and SINR comparison, in lowerthroughputs there is no huge advantage of using 5, 10 or 15 codes, andalso the average SINR is roughly the same. Using average SINR gives apossibility to create a DL link budget for HSDPA. The reason to use SINRis that the HSDPA bit rate and the number of codes can change in everyTTI. Using Eb/No or Es/No in the link budget would require that either thebit rate or the number of the codes is known. The bit rate at cell edge iscommonly lower than 384 kbps.

From the HS-SCCH link budget point of view, it is most important toestimate the power allocated to it, because that also affects the HSDPApower that is left for traffic. HS-SCCH depends on the user location and iscommonly assumed to be about 500 mW at the cell edge (around G-factor-5 dB).

-10 -5 0 5 10 15 20 25 30 35 400

2

4

6

8

10

12

SINR(dB)

Throughput(M

bits/s)

5 codes, PedA

5 codes VehA

5 codes fit

10 codes PedA

10 codes VehA

10 codes fit

15 codes PedA

15 codes VehA

15 codes fit

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Figure 6. User location (as G-factor) versus HS-SCCH power

As discussed, the link budget has to consider the cell edge throughput toget the average SINR, and HS-SCCH has to be estimated to calculate thepower left for HSDPA traffic. Similarly in case of shared carrier betweenthe DL DCH and HSDPA, also the DCH power has to be estimated andtaken into account.

Link budget parameters

1. Service parameters. Service rate. Throughput for HSDPA is defined to calculate the

allowed propagation loss. This affects the SINR requirement,which is needed for getting the wanted service at cell edge.

2. UE parameters

RX Antenna Gain and Handset Noise Figure. Commonly Body Lossis assumed to be 0, but it may occur with VoIP if UE is close to userhead.

3. Node B parameters

0

Avg.req.HS-SCCHpower@

1%

BLEP[W

]

-15 -10 -5 0 5 10 15

0.5

1.0

1.5

2.0

2.5

3.5

4.0

3.0

NODE-B/CPICH POWER 12W/2W1x1-RAKE, 3KM/H, 6MS/1DB LA DELAY/ERROR

Typical macrocellularenvironment (3GPP)

Average G-factor [dB]

Ped-AVeh-A


06/03/2008


. Cable loss and Mast Head Amplifier. Cable loss can beassumed from 0.5 to 3 dB; in case of Flexi BTS remote radiohead (RRH) the cable loss can be as low as 0.5 dB. Whenusing MHA the cable loss is compensated and the benefit fromMHA is same as assumed cable loss. Existing feeders can beused in I-HSPA.

. Antenna gain. Gain varies from sectorised to omni antennas,the antenna gain can be seen from antenna data sheet.

. Downlink EIRP.

Downlink EIRP = HSDPA power - Cable loss - MHA insertionloss + Transmit antenna gain

4. Thermal noise calculation

ThermalNoiseDensity = k x T x B = -108 dBm. k = Boltzmann’s constant, 1.43 E-23 Ws/K. T = Receiver temperature, 293 K. B = Bandwidth, 3 840 000 Hz

5. Interference margin calculation

The link budget uses an interference margin which is calculated asratio of total inference and thermal noise:

Where the signal to interference ratio can be defined for HSDPAtraffic with SINR requirement as:

6. Interference floor

Interference_floor = Thermal noise + UE noise figure +interference_margin

7. Receiver thermal sensitivity

IMI

=N

N+(1- )PBTS

Lp+

N= =

1

1-PBTS

Ptx

Prx

I(1- )+

PBTS

Lp

Prx

I=SINR

SF16

DN70387977Issue 1-1 en draft06/03/2008



. HSDPA uses Spreading Factor 16.

. The receiver thermal sensitivity is computed according to theequation:

Receiver Sensitivity = interference_floor + SINR - SpreadingGain (SF16)

This represents the receiver sensitivity when the system isloaded and an interference margin has been included.

8. Additional parameters. DL fast fading margin. In DL fast fade margin is assumed to be

0 dB in the downlink direction as a result of the limiteddownlink transmit power control dynamic range.

. Gain against shadowing can be up to 2.0 dB, which is used todetermine the selection possibility of stronger cell in normalcell overlapping network

. No SHO for HSDPA.

9. Clutter related parameters

As shown in example link budget the max allowed propagation losscalculation includes also definition of indoor losses and margins.Additional to that the coverage can also be calculated for in-car andoutdoor, but the most commonly the coverage should be calculatedindoors.. Building penetration loss. This parameter is clutter specific,

normally for dense urban areas this value is higher than inrural area. Recommended values for urban is 16 dB andsuburban 12 dB.

. Indoor location probability. This parameter defines theprobability of connection in indoors, value depending on clutterand area, varies from 80 - 95%.

. Indoor standard deviation. Correspondingly clutter and areadependent, varies from 5 to 12 dB.

. Slow fading margin. Slow fading margin is calculated fromindoor location probability and standard deviation. Typicalvalues for slow fading margins for 90-95% coverageprobability are:. Slow fading margin, outdoor: 6 – 8 dB (lower for

suburban and rural). Slow fading margin, indoor: 10 – 15 dB (lower for

suburban and rural)

10. Isotropic power required

Required signal power is calculated to take into account the buildingpenetration loss and indoor standard deviation as well as receiversensitivity and additional margins.


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Isotopic power required = Receiver sensitivity - RxAntennaGain +Body Loss + DL fast fading margin - DL SHO gain - Gain againstshadowing + BPL + Shadowing margin

11. Allowed propagation loss

Allowed propagation loss = EIRP - Isotopic power required

4.3.3 HSDPA associated UL DPCH link budget

Uplink (UL) link budget can be used to define maximum path loss for PSservice. Within Rel-5, UE UL data of the HSDPA connection is carried onassociated DPCH, which is a normal NRT data bearer. Supported datarates for associated DPCH are 16, 64, 128 and 384 kbps. However,additional margin is required in the UL link budget to account for the powerrequirements of HS-DPCCH. HS-DPCCH carries channel qualityinformation (CQI) reports and Ack/Nack feedback for HARQ.

Table Example of HSDPA assocaited UL DPCH link budget showsexample link budgets for different Service Rates.

Table 2. Example of HSDPA associated UL DPCH link budget

Service PS Data PS Data PS Data PS Data

Service Rate (kbps) 16 64 128 384

Transmitter - Handset

Max Tx Power (dBm) 24 24 24 24

HS-DPCCH Overhead 4.6 2.8 1.6 1.1

Tx Antenna Gain (dBi) 2 2 2 2

Body Loss (dB) 0 0 0 0

EIRP (dBm) 21.4 23.2 24.4 24.9

Receiver Node B

Node B Noise Figure(dB)

2


Uplink Load (%) 50

Interference Margin (dB) 3-0

Interference Floor -103.0

Service Eb/No (dB) 2.5 2 1.4 1.7

Service PG (dB) 23.8 17.8 14.8 10.0

DN70387977Issue 1-1 en draft06/03/2008



Table 2. Example of HSDPA associated UL DPCH link budget (cont.)

Service PS Data PS Data PS Data PS Data

Receiver Sensitivity (dB) -124.3 -118.8 -116.4 -111.3

Rx Antenna Gain (dBi) 18.0 18.0 18.0 18.0

Cable Loss (dB) 0.5 0.5 0.5 0.5

Benefit of using MHA(dB)

0 0 0 0

UL Fast Fade Margin(dB)

1.8 1.8 1.8 1.8

UL Soft Handover Gain(dB)

1.5 1.5 1.5 1.5

Gain against shadowing(dB)

2.5 2.5 2.5 2.5

Building PenetrationLoss (dB)

12 12 12 12

Indoor Location Prob.(%)

90 90 90 90

Indoor Standard Dev.(dB)

10 10 10 10

Shadowing margin (dB) 7.8 7.8 7.8 7.8

Isotropic PowerRequired (dB)

-124.2 -118.7 -116.3 -111.2

Allowed Prop. Loss(dB) 145.7 141.9 140.7 136.1

The selection of UL associated DPCH bit rate has to relate to the selectedservice in DL. If using a high bit rate in DL, the UL bit rate can be higher,but in case of high coverage area per cell only lower UL DPCH bit ratescan be used. If ROHC is not supported in mobiles, VoIP will use 64 kbps(Rel-5 UEs), thus this should be the UL limiting service.

From the link budget perspective, I-HSPA brings differences to SHO gain.Implementation consists of two intra-frequency HOs, normal HO and hardhandover. This leads to differences in SHO gain:

. Normal HO leads to the full SHO gain, which at cell edge can be 1.5dB in UL. This may have an impact on transmission, as there is needfor Iur interface.

. Hard handover will lead to SHO gain of 0 dB in UL.


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Using SHO may create advantages in HS-DPCCH overhead. The HS-DPCCH is power controlled relative to the uplink DPCCH for every slotperiod. The power offset parameters (∆ACK; ∆NACK; ∆CQI) are controlledby I-HSPA Adapter and reported to the UE using higher layer signaling.The HS-DPCCH power offset must be increased since the UL HS-DPCCHpower control is sub-optimal for HSDPA-users in soft handover mode (thatis, active set size larger than one). The dominant link in the active set maynot be the one belonging to the cell, which is currently transmitting the HS-PDSCH to the user. Average overhead generated by HS-DPCCH dependsupon activity of ACK/NACK and CQI. Link budgets consider peak ratherthan average overhead.

As noticed there can be either SHO or no SHO which will lead to thedifferent offset. Table HS-DPCCH offset with SHO and without SHO showsthe differences with and without SHO.

Table 3. HS-DPCCH offset with SHO and without SHO

HS-DPCCH offset for link budget [dB]

Bearer Rate 16 kbps 64 kbps 128 kbps 384 kbps

Without SHO 2.4 1.3 0.7 0.5

With SHO 4.6 2.8 1.6 1.1


1. Service parameters. Service bit rate. Bit rate depends on service, which can vary in

packet service bit rates from 16, 64, 128 to 384 kbps.. Service Processing Gain

High processing gains correspond to services with low bitrates. These services tend to have more relaxed link budgetsand generate smaller increments in cell loading.

. Service Eb/No. Eb/No value varies between services and alsobetween selected propagation channels. Table HSDPAassociated UL DPCH Eb/Nos shows example Eb/No valuesfor commonly used services in I-HSPA dimensioning.

Service Processing Gain = 10 * LOGChip Rate

Bit Rate

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Table 4. HSDPA associated UL DPCH Eb/Nos

Uplink DCH EbNo

Bearer Rate 16 kbps 64 kbps 128 kbps 384 kbps

EbNo [dB] (3km/h, macrocell)

2.5 2 1.4 1.7

2. UE parameters. UE max power and antenna gain

UE transmit power is dependent on the mobile type andusually varies between 21 and 24 dBm. Similarly, the antennagain varies from 0 dBi mobile terminals to 2 dBi data cards.

. Body loss

Body loss depends on service. Commonly during the calls themobile is located near the ear, and 3 dB body loss is noticed.

. HS-DPCCH

As described above.. EIRP

EIRP represents the effective isotropic radiated power fromthe transmit antenna. In UL it is computed from the followingequation:

Uplink EIRP = UE Transmit Power + Transmit Antenna Gain -Body Loss

3. Node B parameters. Node B noise figure

NF varies according to frequency and Node B performance.For example, for Flexi WCDMA BTS NF varies from 2 to 2.8dB according to the frequency.

. Antenna gain

Antenna gain varies from sectorised to omni antennas. Theantenna gain can be seen from antenna data sheet.

. Cable loss and Mast Head Amplifier

Cable loss can be assumed to be from 0.5 to 3 dB; in case ofFlexi WCDMA BTS the cable loss can be as low as 0.5 dB.When using MHA, the cable loss is compensated and thebenefit from MHA is the same as the assumed cable loss.

4. Thermal noise

Calculate thermal noise according to the following formula:

ThermalNoiseDensity= k x T x B = -108 dBm


06/03/2008


where:. k = Boltzmann’s constant, 1.43 E-23 Ws/K. T = Receiver temperature, 293 K. B = Bandwidth, 3 840 000 Hz

5. Uplink load factor

Calculate uplink load factor by WCDMA uplink load equation:

ηul Uplink load factor. Generally uplink load of 0.5– 0.7 is used in dimensioning.

N Number of users

Vj L1 activity factor of user j (0.67 for voice UL,0.63 for voice DL, 1.0 for data)

Eb/Noj Received energy per bit-to-noise density ratio(Eb/No) of user j

W WCDMA chip rate; 3.84 Mcps/s

Rj Data rate of user j

A Power rise of user j due to power control,depending on UE speed

i Ratio of other to own cell interference. Inuplink, the value depends on the BTSsectorisation:

Micro cell : Omni: 25% - 55%

Macro cell: Omni: 55%, 2-sector: 55%, 3-sector: 65%, 4-sector: 75%, 6-sector: 85%

It is recommended to use the maximum uplink load of 0.5–0.7, evenif in the initial phase of the network the subscriber traffic would notgenerate as much load. This is to avoid a situation where slightincreases in the traffic amounts may cause shrinkage of thecoverage areas. In rural areas, where major traffic is not expected, alower uplink load value may be used.

6. Interference margin

This is calculated from the load factor.

=UL

Eb / Noj

W / Rj

v jj=1

j=N

* (1+ a * i)

DN70387977Issue 1-1 en draft06/03/2008



7. Interference Floor

Interference Floor is calculated from the load factor.

Interference_floor = Thermal noise + Node B noise figure +intereference_margin

8. Receiver thermal sensitivity.

The receiver thermal sensitivity is computed according to theequation:

Receiver Sensitivity = Interference_floor + Required Eb/No -Processing Gain

9. Additional parameters.. UL fast fade margin, that is, power control headroom. The

recommended value for slow moving mobiles is 1.8 dB. Forfast moving mobiles it is 0 dB.

. Gain against shadowing. The recommended value is 2.5 dB.

. UL soft handover gain. The recommended value is 1.5 dB.

10. Isotropic power

The required signal power is calculated to take into account thebuilding penetration loss and indoor standard deviation, as well asreceiver sensitivity and additional margins.

Isotropic power required = Receiver sensitivity - RxAntennaGain +cable loss - MHA gain + UL fast fade margin – Gain againstshadowing – UL SHO gain + BPL + shadowing margin

11. Allowed propagation loss

Allowedprop loss = EIRP - Isotropic power required

4.3.4 HSUPA link budget

HSUPA link budget is similar to HSDPA associated UL DPCH link budget.Table Example of HSUPA link budget shows an example of HSUPA linkbudget.

Interference_margin= -10 * LOG 1- TARGET_LOAD

100


06/03/2008


Table 5. Example of HSUPA link budget

Uplink Service

Cell Edge Throughput(kbps)

64

Target BLER (%) 10

Propagation Channel Pedestrian A 3 km/h

Channel HSUPA

Service PS Data

Service Rate (kbps) 64

Transmitter - UE

Max Tx Power 24

HS-DPCCH Overhead 2.5

Tx Antenna Gain (dBi) 2

Body Loss (dB) 0

EIRP (dBm) 23.5

Receiver - Node B

Node B Noise Figure (dB) 2


Uplink Load (%) 50

Interference Margin (dB) 3.0

Own ConnectionInterference

0.08

InterferenceFloor (dBm) -103.1

Service Eb/No (dB) 0.2

Service PG (dB) 17.78

Receiver Sensitivity (dBm) -120.65

Rx Antenna Gain (dBi) 18

Cable Loss (dB)s 0.5

Benefit of using MHA (dB) 0

UL Fast Fade Margin (dB) 1.8

UL Soft Handover Gain(dB)

1.5

Gain against shadowing(dB)

2.5

Building Penetration Loss(dB)

12

DN70387977Issue 1-1 en draft06/03/2008



Table 5. Example of HSUPA link budget (cont.)

Uplink Service

Indoor Location Prob. (dB) 90

Indoor Standard Dev. (dB) 10

Shadowing margin (dB) 7.8

Isotropic Power Required(dB)

-120.6

Allowed Prop. Loss (dB) 144.0

Main differences are related to:

. Different service rates

. Different Eb/Nos

. Different HS-DPCCH overhead

. Different own connection interference

In uplink (UL) the main I-HSPA service is HSUPA. When comparing toHSDPA link budget, HSUPA has similar differences as HSDPA associatedUL DPCH:

. HS-DPCCH, result varies between data rate as well as in case ofSHO or no SHO.

. SHO gain which varies between cases of partial SHO, as the E-DCHcannot be carried over Iur, or Hard handover.

HS-DPCCH overhead is dependent on bit rate. Table HS-DPCCHoverhead for HSUPA with and without SHO shows the overhead valueswith soft handover and without soft handover.

From the link budget perspective I-HSPA brings differences to SHO gain.Implementation consists of two intra-frequency HOs, partial HO and hardhandover. This leads to the difference in SHO gain:


06/03/2008


. Full HO leads to full SHO. Full SHO gain at cell edge can be 1.5 dBat cell edge. Full SHO is not supported for HSUPA in I-HSPA release1 as user plane does not have SHO over Iur, follow partial HO for I-HSPA release 1.

. Partial HO leads to the partial SHO gain, which at cell edge can be 0to 1 dB in UL, recommended to use 0.5 dB. The control plane can becarried over the Iur but not on the user plane. This case the HS-DPCCH overhead have to be selected from table with SHO.

. Hard handover will lead to SHO gain of 0 dB in UL. Similarly theoverhead will be from no SHO, thus lower.


1. Service parameters

You can define the throughput for HSUPA to calculate the allowedpropagation loss. This affects the Eb/No requirement for service atcell edge.

2. Service Eb/No

You can define the throughput for HSUPA cell edge to calculate theallowed propagation loss. Table HSUPA Eb/Nos for different datarates shows an example of simulated Eb/Nos for HSUPA.

Table 6. HSUPA Eb/Nos for different data rates

Layer 1 Bit Rate TTI (ms) Physical Channel Eb/No with RxDiv

1920.0 10 2*SF2 0.5

1440.0 10 2*SF2 0.1

1024.0 10 2*SF2 0.2

512.0 10 2*SF4 0.6

384.0 10 1*SF4 0.9

256.0 10 1*SF4 1.1

128.0 10 1*SF8 1.9

64.0 10 1*SF16 2.7

32.0 10 1*SF32 3.8

3. HS-DPCCH overhead is dependent on bit rate. Table HS-DPCCHoverhead for HSUPA with and without SHO shows the overheadvalues with SHO and without SHO.

DN70387977Issue 1-1 en draft06/03/2008



Table 7. HS-DPCCH overhead for HSUPA with and without SHO

HS-DPCCH offset for link budget [dB]

Bearer Rate 35 kbps 69 kbps 103kbps

170kbps

474kbps

810kbps

1146kbps

WithoutSHO

3.0 2.5 1.9 1.3 0.9 0.6 0.4

With SHO 1.5 1.2 0.9 0.6 0.4 0.3 0.2

4. UE parameters. UE max power and antenna gain

UE transmit power is dependent on the mobile type andusually varies between 21 and 24 dBm. Similarly, the antennagain varies from 0 dBi mobile terminals to 2 dBi data cards.

. Body loss

Body loss depends on service. Commonly during the calls themobile is located near the ear, and 3 dB body loss is noticed.

. HS-DPCCH

As described above.. EIRP

EIRP represents the effective isotropic radiated power fromthe transmit antenna. In UL it is computed from the followingequation:

Uplink EIRP = UE Transmit Power + Transmit Antenna Gain -Body Loss

5. Node B parameters. Node B noise figure

NF varies according to frequency and Node B performance.For example, for Flexi BTS NF varies from 2 to 2.8 dBaccording to the frequency.

. Antenna gain

Antenna gain varies from sectorised to omni antennas. Theantenna gain can be seen from antenna data sheet.

. Cable loss and Mast Head Amplifier

Cable loss can be assumed to be from 0.5 to 3 dB; in case ofFlexi BTS remote radio head (RRH) the cable loss can be aslow as 0.5 dB. When using MHA, the cable loss iscompensated and the benefit from MHA is the same as theassumed cable loss.

6. Additional parameter differences


06/03/2008


. Own connection interference. Own connection interferencefactor reduces the uplink interference floor by the UE’s owncontribution to the uplink interference, that is, by the desireduplink signal power. This means that the own connectioncontribution has to be noted in the interference floorcalculation. The formula for calculating own connectioninterference contribution is as follows:

. Interference floor. Based on the above mentioned modificationthe interference floor is calculated as follows:

Interference_floor = Thermal noise + Node B noise figure +interference_margin - own_connection_interference

Other parameters are identical as earlier shown for HSDPA and HSDPAassociated UL DPCH:

. Antenna gains, cable losses.

. Noise figures and body losses.

. Other margins and losses are the same.

In downlink HSUPA connections make use of HSDPA in the downlinkdirection. For the SRB, DPCH 3.4 kbps is needed.

4.3.5 Cell range and coverage

As shown, the link budget can already include the margins, for example toidentify the allowed propagation loss in indoor location.

The cell range calculation can be made by using either uplink or downlinkpath loss. Most commonly the uplink path loss is used to calculate thecoverage. But in network dimensioning, the link budget calculation has tobe made for every service, and the limiting one has to be selected for thecell range. In I-HSPA the service definition as cell edge throughput has toconsider the uplink HSUPA or HSDPA associated UL DPCH and downlinkHSDPA.

The cell range and coverage is based on:

Own_connection_int = 10LOG 1+

Eb

No

W

R

DN70387977Issue 1-1 en draft06/03/2008



. System parameters as shown in link budget.

. Taking into account margins to guarantee service for example, inindoor, in-car or outdoor:. Building penetration loss, car penetration loss or outdoor when

no penetration loss.. Location probability.. Standard deviation.

. Calculating the cell range by using propagation model like Okumura-Hata model when also noticing the:. Frequency, for example, 2100 MHz.. Node B antenna height, for example, 30 meters.. UE antenna height, for example, 1.5 meters.. Clutter correction factor, which is related to the type of clutter.

As an example Dense urban (3…0 dB), Urban (0…-3 dB) andSuburban (-5…-8 dB).

For example, in urban macro environment, Node B antenna height is 30 m,MS antenna height is 1.5 m and carrier frequency is 1950 MHz:

. L = 137.4 + 35.2*log(R).

Where L is the path loss and R is the range in kilometres. For suburban wecan assume clutter correction factor for example, 8 dB and calculate thepath loss as follows:

. L = 129.4 + 35.2*log(R).

Indoor cell range (taking into account the 64 kbps UL DPCH path loss):

. · R = 10^((141.9-129.4) / 35.2) = 2.27 km

Node B coverage area calculation (depending on the number of sectors inNode B):


06/03/2008


. A=K*R2

. K-factor; depending on the Node B sectorisation:

Figure 7. Node B sectorisation

. For 3 sector A = 1.95 * (2.27 km)2 = 10.05 km2.

4.4 Capacity dimensioning

4.4.1 Overview of capacity dimensioning

Capacity dimensioning is main aspect after coverage dimensioning.Coverage has to be sufficient to offer high throughputs and the averagecell capacity must be able to support traffic demand.

The capacity dimensioning is divided in two parts:

. Downlink capacity dimensioning, where HSDPA capacity can beestimated for average cell throughput.

. Uplink capacity dimensioning, where HSUPA as well as HSDPAassociated UL DPCH capacity is estimated. Commonly UL DPCHtraffic demand is estimated as partly consuming UL load, which isutilized to estimate the HSUPA cell average throughput.

HSDPA capacity estimation is based on power calculation and userdistribution in a cell area. One way to estimate capacity is to utilize thesignal condition based on simulated SINR. SINR includes the effect of linkadaptation, thus variation of number of codes as well as HARQ is included.System level simulation can be used to estimate the maximal capacity andused as a reference to understand the downlink capacity.

R

OmniA = 2,6 R1

R

Bi-sectorA = 1,73 R2

R

R

Tri-sectorA = 1,95 R3

2 2 2

DN70387977Issue 1-1 en draft06/03/2008



In HSUPA capacity estimation the load of the UL DPCH is noticed. ULDPCH is used for Rel-5 UEs, which do not support HSUPA for UL. InHSUPA the amount of users is noticed in the throughput calculation whichthen are given equal share of available UL load (after UL DPCH). C/I iscalculated based on the available load. Throughput can be found from thesimulated Eb/No tables as C/I = Eb/No – W/R (processing gain).

Node B capacity is defined by the following:

. Dedicated channel (HSDPA associated UL DPCH) capacity for UL.

. HSDPA (HS-DSCH) capacity.

. HSUPA (E-DCH) capacity.

DCH capacity is determined by the following:

. Baseband processing configuration.

. Radio network plan, for example, intercell interference and cellrange.

. Node B RF configuration, for example, sectors and carriers.

HSDPA capacity is determined by the following:

. Need of baseband capacity.

. Parameters in use, for example, the number of codes and roundrobin/proportional fair scheduling (PF gain).

. Available Node B power.

. Average cell throughput.

HSUPA capacity is determined by the following:

. Need of baseband capacity, depending on simultaneous HSUPAusers.

. Available UL load for HSUPA.

. Average cell throughput.

For more information on capacity dimensioning in downlink, see Downlinkcapacity.

For more information on capacity dimensioning in uplink, see Uplinkcapacity.


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4.4.2 Downlink capacity

In I-HSPA, downlink power is fully allocated to the HSDPA, althoughCCCH power is needed. HSDPA power also has to account for the HS-SCCH (control) and DPCH (signaling) power, which are commonly from0.5 to 1.0 W at the cell edge for one user (around G-factor -5 dB). Incapacity dimensioning the users are distributed in the cell, thus theaverage HS-SCCH power is much less than 500 mW, but depending onthe amount of active HSDPA users. Values from 0.2 W to as high as 1.5 Wcan be assumed in capacity dimensioning for more than one user.

Figure HSDPA power allocation in I-HSPA shows the power allocation in I-HSPA.

Figure 8. HSDPA power allocation in I-HSPA

HSDPA throughput depends directly on radio channel conditions. Theseconditions are changing rapidly all the time due to fast fading of the radiochannel. BTS is able to change the link adaptation for each 2ms TTI,based on the channel measurements. This means that the achievedthroughput is different in every TTI. The average throughput for a locationcan be estimated if the average SINR (Signal to Interference + NoiseRatio) is known. Commonly simulation results are used for estimating theaverage SINR. Figure Throughput and SINR comparison shows SINR andthroughput with different codes.

HSDPA downlink link budget utilises the average SINR and throughputmapping, which are commonly based on the simulations. An accurateSINR can be calculated when you know HSDPA power, BTS total Txpower, orthogonality and G factor and the user throughput can beestimated. The calculation is done using the following formula:

P_WBTSmax(For example, 20W)

100%

20%

totaltransmittedpower

PtxTotal[dBm]

HSDPA power

CCCH power (~20%)

DN70387977Issue 1-1 en draft06/03/2008



where

. PHSDPA = HSDPA Tx power

. Ptot = total WBTS Tx power

. α = DL orthogonality factor

. SF16 = spreading factor of 16

. G = G-factor

G-factor reflects the distance between the MS and the BS antenna. Atypical range is from -5 dB (Cell Edge) to 20 dB. G-factor is correlated toEc/Io:

where

. PCPICH = CPICH channel transmission power

. PTOT = BS total transmission power at the time of Ec/Iomeasurement

There is not much advantage in using 5, 10 or 15 codes in lowerthroughputs, also the average SINR is around the same. The bit rate at celledge is commonly lower than 384 kbps, but inside the loaded cell high bitrates such as 2 Mbps are possible. In order to estimate the cell averagethroughput the user distribution needs to be taken into account, cellaverage throughput doesn’t estimate possible peak bit rates.

The user distribution (called also as G-factor) reflects to the distancebetween the MS and BS antenna and a typical range is from -5 dB (CellEdge) to 20dB. When setting a value for G-factor means makingassumptions on user location.

SINR = SF16

HSDPAP

totP 1 - + 1

G

CPICHP

TOTP 1 + 1

G

E

IC

O

=


06/03/2008


HSDPA cell average throughput is influenced by:

. Available HSDPA power.

. User distribution.

. SINR, which is additionally influenced by orthogonality.

HSDPA throughput depends on system features such as the following:

. Scheduler type; cell specific or shared scheduler.

. Scheduling type; round robin or proportional fair.

. Number of codes in use; 5, 10, 15 codes.

Most common case in I-HSPA is the presence of a cell specific scheduler,proportional fair and 15 codes. Figure Example simulation results ofHSDPA cell throughput shows an example simulation of how the differentissues and UE enhancements influence HSDPA cell throughput.

Figure 9. Example simulation results of HSDPA cell throughput

0

500

1000

1500

2000

2500

3000

3500

4000

4500

Rake 1-ant Equalizer 1-ant Rake 2-ant Equalizer 2-ant

kbps

Round robin 5 codes

Round robin 10 codes

Proportional fair 5 codes



DN70387977Issue 1-1 en draft06/03/2008



The simulations show also that the PF provides around 30% gaincompared to the RR.

Figure Example simulation results of HSDPA cell throughput shows thatthe different UE type and also the scheduling type as well as the number ofcodes influence cell throughput.

4.4.3 Uplink capacity

Uplink capacity needs to account for UL DPCH and HSUPA traffic. ULDPCH traffic depends on the UE. Rel-5 UEs do not support HSUPA, thusthe UL traffic is carried with the UL DPCH, which can be 16, 64, 128 or 384kbps RAB. This influences formula with Eb/No and processing gain as theservice bit rate changes.

Capacity dimensioning can include one user throughput estimation orwhole cell throughput estimation. The following issues affect capacitydimensioning:

. Available load for HSUPA.

. User location.

. Number of users.

. Load equation parameters, that is, intercell interference ratio whichdepends on sectorization.

The load generated by the associated UL DPCH can be estimated byusing traffic calculations with fractional load formula or comparing them tothe system level simulations’ capacity results. The capacity needed forHSDPA associated UL DPCH influences the HSUPA capacity. Figure Loadestimation for UL DPCH and HSUPA shows an example of capacitydistribution for UL DPCH and HSUPA.


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Figure 10. Load estimation for UL DPCH and HSUPA

Follow these steps to perform HSUPA capacity dimensioning.

1. Estimate the uplink load of DCH users and define the target uplinkload margin.

As already mentioned the HSUPA capacity dimensioning has tonotice also the capacity used for HSDPA associated UL DPCHtraffic. In case if the UL DPCH uplink load is 21 % and the maximumtarget UL load is set to 80 % then HSUPA capacity is 80 % - 21 % =59 %. This 59 % can be used to define the capacity for HSUPA.

2. The uplink load is translated to uplink C/I using the uplink loadequation.

C/I is translated to HSUPA bit rate using the Eb/No look-up tablederived from link level simulations.

0

2

4

6

8

10

12IncreaseinInterference(dB)

Uplink Loadgenerated byR99 DCH

Uplink Loadavailable forHSUPA UE

0 20 40 60 80 100

Uplink Load (%)Example TargetUplink Load

=

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This information can be used to estimate the throughput in area withestimated parameters. The available load can be divided toexpected amount of HSUPA users.

3. Divide the available uplink load between expected number ofHSUPA users.

The available HSUPA load has to be divided equally to everyHSUPA user. When increasing the number of users, each user willhave lower throughput due to the decreasing available load, thusinfluencing at the end the C/I. As a result of this step, all users willhave the same available load and also the same C/I.

To go into more detail, also the estimated HSUPA user location canbe used to estimate user throughput.

4. Estimate the link losses between the expected locations of HSUPAusers and the BTS. This way you can get the average cellthroughput by estimating the share of bad coverage HSUPA usersand good coverage users, for example. Figure Example of HSUPAuser distribution on cell area shows an example distribution of fiveusers.

Figure 11. Example of HSUPA user distribution on cell area

The location can be estimated by introducing path loss offsets todetermine the path loss for each UE. C/I can be calculated asfollows.

0.0

500.0

1000.0

1500.0

2000.0

2500.0

3000.0

3500.0

4000.0

0.0 1000.0 2000.0 3000.0 4000.0

UE5

UE4

UE3

UE2

UE1

antenna

link budgetprovidesthe cell edgepath loss

ylocation

x location


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where. Wanted signal is the signal strength which is calculated from

the link budget, assuming that the UE is transmitting atmaximum power. The path loss offset can be introduced todetermine the user location from the cell edge.

. Interference floor is calculated as:

Interference_floor = Thermal noise + Node B noise figure +interference_margin

5. Verify that the user receives the service.

If the UE furthest from the cell cannot achieve the equal share C/I(step 2.), its share of the uplink load is decreased to correspond totheir maximum achievable C/I, and you can utilise the load with otherusers who can achieve the level.

As a result of capacity dimensioning, you can:

. Estimate the user throughput based on its location and availableload.

. Estimate user throughput based on C/I estimation.

. Estimate the cell throughput based on users equal load and C/I.

. Estimate the cell throughput based on different user location, whichcan influence the load and C/I.

C / I = 10xLOGWantedSignal

Interf.Floor - WantedSignal

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5 Dimensioning hardware

5.1 Introduction to dimensioning Node B

I-HSPA supports Flexi WCDMA BTS. Flexi Wideband Code DivisionMultiple Access (WCDMA) BTS is a modular, compact, and high capacitywide-area WCDMA BTS that can be used in various indoor and outdoorinstallation options (such as floor, wall, stand, pole, mast, cabinet, 19"rack) and site applications (mini, macro, and distributed site solution).

Flexi WCDMA BTS consists of the following self-supporting BTS modules:

. Radio Module, which provides the Radio Frequency (RF)functionality.

. System Module, which provides baseband processing as well ascontrol and transmission functionality.

. System Module provides up to 240 CE capacity. The number of CEsactivated can be increased by licence control.

. The baseband Extension Module is also available, increasing FlexiWCDMA BTS capacity to 2*240 = 480 CE.

. Optional power supply module.

Optional outdoor cabinet is also available.

Figure Flexi WCDMA BTS with I-HSPA (1+1+1 configuration) shows theFlexi WCDMA BTS with I-HSPA.

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Dimensioning hardware

Figure 12. Flexi WCDMA BTS with I-HSPA (1+1+1 configuration)

Flexi WCDMA BTS provides I-HSPA configurations up to three sectors.The output power options of 8/20/40W are available. The following Flexi20/40W per carrier configurations are available in I-HSPA release 1: 1, 1+1, 1+1+1. 1 omni configuration is also available with 8W option.

One Radio Module can support one or two sectors. For 1+1+1 (min 40Wper carrier) or 2+2+2 (min 20W per carrier) configurations one SystemModule and two Radio Modules are required for a complete a WCDMABTS setup. Baseband capacity of the system module can be addedremotely with a SW license when needed.

I-HSPA Flexi WCDMA BTS System Module capacity is:

. 240 CE, no common channels (with two system modules 480 CEs)

. 240 CE - 26 CE = 214 CE with 1-3 cells (26 CE needed for CCCHs)

. 240 CE - 52 CE = 188 CE with 4-6 cells (52 CE needed for CCCHs)

5.2 Node B dimensioning

The Node B dimensioning with I-HSPA does not have major differenceswhen compared to common Flexi Node B dimensioning. Previous sectionlisted the maximum CE capacities, one System Module 240 CEs and twoSystem Modules 480 CEs. All channel elements can be used for I-HSPAtraffic generated by Release 5 and 6 terminals.

RF Module 2*50W

RF Module 1*50W

System Module

I-HSPA adapter

Power Module

DC

Iub

Iu

Sector 1

Sector 3

Sector 2

AC(optional)


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I-HSPA Node B needs to be dimensioned for traffic generated by:

. Release 5 terminals, which support HSDPA associated UL DPCHand HSDPA.

. Release 6 terminals, which support HSDPA and HSUPA.

The amount of traffic generated to uplink depends on HSDPA associatedUL DPCH. Table Flexi I-HSPA BTS (1+1+1) processing capacity forHSDPA associated UL DPCH shows the HSDPA associated UL DPCHbearers channel element (CE) consumption per service.

Table 8. Flexi I-HSPA BTS (1+1+1) processing capacity for HSDPAassociated UL DPCH

User dataCE required inUL Min SF

CE required inDL/Min SF

PS 16 kbps 1/SF64* 1/SF128**

PS 64 kbps 4/SF16 1/SF128**

PS 128 kbps 4/SF8 1/SF128**

PS 384 kbps 16/SF4 1/SF128**

*) If SF is 32, 2 CE is required in UL

**) 1 CE for DL signalling is required per HSDPA user

There are different features that impact CE usage in HSDPA. For example,the following features have influence on CE need:

. HSDPA 16 Users per Cell

. HSDPA 48 Users per Cell

. Shared HSDPA Scheduler for Baseband Efficiency

. HSDPA 15 Codes

New schedulers, namely Shared HSDPA Scheduler for BasebandEfficiency and HSDPA 48 Users per Cell, are introduced to support bitrates beyond 3.6 Mbps. HSDPA with schedulers that allow a maximum of5 HS-PDSCH codes takes 32 CE capacity in the Flexi Submodule thathandles HSDPA cells (MAC-hs). Other CEs left can be used for othertypes of traffic.

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HSDPA with 15 HS-PDSCH codes takes 80 CE capacity in FlexiSubmodule. No CE is left in the Flexi Submodule for other channels.HSDPA 48 Users per Cell and Shared HSDPA Scheduler for BasebandEfficiency require 80 CE in Flexi Submodule, with 5 or 15 codes.

Table HSDPA CE usage gives the HSDPA CE usage with 5, 10 and 15codes and different features..

Table 9. HSDPA CE usage

Feature 5 codes 10 codes 15 codes

CErequired

Maxthroughputper cell

(Mbps)

MaxthroughputperBTS

(Mbps)

CErequired


(Mbps)

Maxthroughput perBTS

(Mbps)

CErequired


(Mbps)

MaxthroughputperBTS

(Mbps)

HSDPA 16Users per BTS

32 3.6 3.6 N/A N/A N/A N/A N/A N/A

HSDPA 16Users per cell

96 3.6 10.8 N/A N/A N/A N/A N/A N/A

Shared HSDPAScheduler forBasebandEfficiency (48users per BTS)

64 3.6 10.8 64 3.6 (9.6) 10.8 64 3.6 [7.2] 10.8

+ with HSDPACodeMultiplexingfeature

N/A N/A N/A 64 7.2 (9.6) 10.8 64 10.8 10.8

HSDPA 48Users per Cell

192 3.6 10.8 192 3.6 (9.6) 10.8(28.8)

192 3.6 [7.2] 10.8[21.6]

+ with HSDPACodeMultiplexingfeature

N/A N/A N/A 192 7.2 (9.6) 21.6(28.8)

192 10.8[14.4]

32.4[43.2]

The figures in parentheses assume that 10-code phones are used in thenetwork.

The figures in square brackets ([]) assume that 15-code phones are usedin the network.


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Table HSDPA scheduler types gives the maximum numbers of HSDPAschedulers that can be simultaneously active per scheduler type. Note thatonly one type of schedulers can be activated in the BTS at a time, andsimilarly next table corresponds to I-HSPA.

Table 10. HSDPA scheduler types

HSDPA scheduler typeFlexi WCDMABTS, 1 SystemModule

Flexi WCDMABTS, 2 SystemModules

Basic HSDPA, 16 Users perBTS/LCG (shared scheduler)

1 (2*) 1 (2*)

HSDPA 16 Users per Cell (celldedicated scheduler)

3 3

Shared HSDPA Scheduler forBaseband Efficiency

1 (2*) 1 (2*)

HSDPA 48 Users per Cell (celldedicated scheduler)

2 3

*) Tcell parameter tuning is required in the RNC.

HSUPA CE consumption depends on amount of HSUPA users and L1 bitrate. For HSUPA maximum of 160 CEs (two Flexi Submodules) can beused and this amount is dynamically shared between HSDPA associatedUL DPCH and HSUPA. Thus capacity is reserved for HSUPA on needbasis.

The operator may commission a minimum fixed reservation for HSUPA,but the rest of the capacity is dynamically allocated to HSUPA whenHSDPA associated UL DPCH does not need it. HSUPA reserves CEs inuplink and downlink. Additionally, DPCCH for I-HSPA needs one extra CEper HSUPA user in uplink and downlink.

HSUPA is supported only in co-existence with HSDPA.

The minimum capacity reserved for HSUPA is eight CE. In this case, onlyHSUPA MAC-e is active. As default, the eight CE reservation is done whenthe first HSUPA cell is configured to the local cell group. The operator canfollow the capacity need from the counter indicating the number of HSUPAcapable UEs in the cell.

The BTS reserves minimum capacity for HSUPA based on the followingcommissioning parameters: Minimum baseband decoding capability

Mbps and Minimum number of HSUPA UE per BTS.

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The value for Minimum baseband decoding capability Mbps refers to thestatic commissioned minimum reservation for baseband L1 throughput.HSUPA throughput may be bigger if there is more capacity available in theBTS.

Table HSUPA CE consumption in I-HSPA gives examples of CE utilisationfigures for Flexi I-HSPA BTS HSUPA traffic.

For example, BTS HSUPA traffic is expected to be at maximum of eightusers simultaneously and total HSUPA traffic to be up to 2.8 Mbps on L1.According to table HSUPA CE consumption in I-HSPA, 56 CEs arerequired for HSUPA.

Table 11. HSUPA CE consumption in I-HSPA

Flexi WCDMABTS

Baseband decoding capability, Mbps

Number of HSUPAUE per BTS

0 <1.4 1.4 2.8 4.2 5.6

0 8 8 8 8 8 8

1-4 8 32 32 56 80 112

5-8 8 32 56 56 80 112

9-12 8 56 56 80 80 112

13-16 8 56 80 112 112 112

17-20 8 80 80 112 136 136

21-24 8 80 80 112 136 160

HSUPA CE allocation is done with specific sizes of resource steps. Theamount of resources needed depends on the desired throughput and thenumber of HSUPA users.

HSUPA activation requires a fixed pool of eight CE when activating thefeature. HSUPA resource step 1 is preallocated by the HSUPA ResourceManager, enabling fast HSUPA call setup. The preallocation is not visiblein CE counters.

To be able to allocate the next HSUPA resource step, an additional freecapacity of six CE is needed. This six CE does not need to be free in theHSUPA resources area; but it can be any licensed CE. The required sixCE free on top of the HSUPA resource step is to avoid a 'ping-pong' effectin reserving and freeing HSUPA resource steps. This is needed so that theHSUPA resource step is not requested back immediately after itsallocation.


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When free channel capacity drops below four CE, the Resource Managerstarts to request back HSUPA resources. If HSPA sharing is in use, it takesthe capacity of one resource step, that is, 32 CE. Table HSUPA resourcesteps in I-HSPA gives the size of each HSUPA resource step.

Table 12. HSUPA resource steps in I-HSPA

HSUPA resourcestep

Flexi WCDMABTS

1 32 CE

2 24 CE

3 24 CE

4 32 CE

5 24 CE

6 24 CE

5.3 I-HSPA Adapter dimensioning

There are several capacity license steps for I-HSPA Adapter. Table I-HSPArelease 1 capacity license steps gives the capacity license steps for I-HSPA release 1.

Table 13. I-HSPA release 1 capacity license steps

Capacity license steps, I-HSPArelease 1

Throughput

Capacity step 1 HSPA 1.8/0.6 Mbps (DL/UL

Capacity step 2 HSPA 3.6/1.2 Mbps (DL/UL)


Throughput limitation is based on software license and I-HSPA Adapterhardware has higher capacity. No hardware change is required whenlicense is upgraded. This doesn't limit system peak rate capabilities at celllevel.

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6 Planning Air interface

6.1 Introduction to planning Air interface

This chapter explains the principles and different phases of radio networkplanning in I-HSPA. The detailed radio network planning process identifiesspecific site locations and refines their configurations to suit to the localenvironment and traffic profile.

Radio network planning is related to the good overall networkperformance. It is dependent on actual traffic and user behaviour. Thestate of radio network is changing fast and it is important to have animmediate feedback loop from the operational network, such asperformance measurements. In this sense, radio network planning isclosely related to the optimization of radio network.

Figure High level planning process including optimization shows theplanning phases.

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Planning Air interface

Figure 13. High level planning process including optimization

Dimensioning is a major task during the pre-planning phase. Dimensioningresults are used in detailed planning for strategy information to provideestimations. Detailed planning consists of more accurate tasks andestimations. Similarly the accuracy of inputs need to be high as thedetailed planning results are used for selecting site location, configurationand additional coverage, capacity and parameter strategies. Detailedplanning can include the following phases:

. Model tuning

. Site selection

. Coverage and capacity planning

. Configuration planning

. Parameter planning

The implementation of I-HSPA networks brings a new approach toplanning, as CS services are handled through existing GSM or WCDMAnetwork or no CS services are offered. This does not create differences inradio interface as the neighbour definition is as important as in earliertechnologies. In case I-HSPA is deployed without CS service enabling HO,Air interface planning may be even easier than traditional WCDMAplanning. This is an addition to the fact that there is no need to estimate CSservices and downlink R99 PS services, which leads to the fact that

Pre-planning

Pre-planninginformation

Dimensioning

Detailed planning

Model tuning

Site selection

Coverage andcapacity planning

Configurationplanning

Parameterplanning

Optimization

Pre-launchoptimization

Post-launchoptimization


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coverage and capacity planning does not need to take multiple servicesinto account. This means that all power in DL is used for HSDPA and in ULall capacity is available for PS service through HSDPA associated ULDPCH or HSUPA.

In I-HSPA networks, the coverage and capacity of cells are interrelatedand need to be accounted for by accurate statistical analysis to derivemargins and gains. I-HSPA networks can be planned by simulatingnetworks using Monte Carlo algorithms. This planning approach createssnapshots of the network in time. It uses statistical distributions andmultiple iterations to account for the randomness of the propagationenvironment. This is the approach used by the NetAct Planner to estimatecoverage and capacity for predefined network. This also evaluates theinterference in the network, which is the main limiting factor of a WCDMA-based technology. Interference analysis is crucial already in the coverageprediction phase.

Traffic in I-HSPA networks consists of PS traffic with different data rates,arrival rates, and tolerance to delay and noise. Traffic is asymmetrical indownlink and uplink, while downlink is more heavily loaded than uplink.With HSDPA, downlink can generate peak rates up to 10 Mbps, while inuplink HSUPA enables peak rates over 1.5 Mbps. Radio network planningneeds to be a well-planned process, in which aspects related to capacityand coverage tradeoff and quality of service (QoS) are considered.Although the amount of services in I-HSPA is lower, QoS requirementshave to be be set and met, together with new challenges coming in theform of VoIP service.

Planning issues are interconnected and should be consideredsimultaneously. An example of such a planning issue is co-locating I-HSPAand traditional WCDMA/GSM sites. This needs to consider services aswell as coverage continuity in case of either CS service handover or I-HSPA coverage limitations due to the rollout strategy. Similarly theusability of existing location has to be evaluated, as it may have a highimpact on coverage and/or capacity in the end.

Coverage and capacity planning as well as site selection are based oninformation previously available to the operator, traffic estimates per area,propagation maps and other estimations. After detailed planning, capacityand coverage have been analysed for each cell, and cell configuration andparameters have been defined.

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6.2 Planning Air interface

Purpose

This procedure outlines the planning of I-HSPA Air interface.

Before you start

Check that following information and tools are available:

. Dimensioning has been completed and its results and inputs areavailable, especially regarding what should be covered, by whichservices and at which quality.

. NetAct Planner tool is available. For more information, see NetActPlanner Product Documentation.

. Operator requirements and all supporting materials are available.

. Network evolution expectations regarding capacity growth andspecifically affected bearers are available.

Check that the following inputs used in WCDMA radio network planningare available:

. Traffic expectation is one of the most important inputs, but alsodifficult to define. It should be defined on a per service basis and interms of the number of simultaneous active subscribers, UL and DLservice bit rates, UL and DL activity factors, and the geographicdistribution according to clutter types. Special use cases such asbusiness users and other high-end users should also be analysed.

. Coverage and quality objectives. The service coverage performanceshould be specified on a per service and per clutter basis for indoor,outdoor, and in-car environments.

Table 14. Sample of coverage objectives in terms of service availability

Dense urbanindoor

Urban indoor Suburbanindoor

Rural

In-car

Uplink service bit rate 128 kbps 128 kbps 128 kbps 64 kbps

Service availability 95% 95% 95% 95%


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Service quality objectives are defined in terms of block error rateapplied to packet-switched data, and in terms of delay aspects forVoIP. It has to be noted that in WCDMA, different services havedifferent processing gains and quality requirements regarding biterror ratio and frame error ratio. Therefore, services have differentreceiver signal-to-interference ratio requirements. Consequently,coverage depends on the services used in cells.

Additional quality requirements are listed below.. Coverage probability. Blocking probability. End user throughput. Offered services. UE penetration. Location probability

. Site database or information.

An initial site database should be made available based on the sitesof the operator. Sites should be prioritized in terms of site selectioncriteria. New sites can be added when there is a need for additionalcoverage and capacity.

. Maximum cell load.

Appropriate level of maximum cell load should be identified duringdimensioning. It defines the required site density for achieving thetarget capacity and coverage objectives. The planned cell load musttake into account the growth of traffic in the network.

. Propagation model.

Propagation models should be calibrated for each environment ofthe planned network. Propagation calculation principles are thesame in I-HSPA as in other technologies.

. Default system configuration parameter set.

Default parameter sets should be defined for each environment.They provide the initial cell configuration for planning activities.

. Link and system parameters.

Link and system hardware performance figures are needed for anaccurate representation of the live network. Parameters includeservice Eb/N0 requirements, fast fading margins, orthogonality, softhandover gains and receiver noise figures.

. Parameter planning.

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There are multiple parameters which need to be set in order forproper network functionality. For example, code planning is needed.The total number of scrambling codes is 512, in which there are 64code groups and each group contains eight codes. The codes canall be used in adjacent cells, even if they belong to the same codegroup, so the code reuse factor can be up to 512, which shouldmake the code planning simple although some care needs to betaken to avoid scrambling code conflicts between neighbours.

Like the previous input in I-HSPA networks, site and sector planning isdone in the same way as in traditional WCDMA/GSM networks. The maindifference is the importance and focus on PS services and possibility ofCS speech control, which can be through feature CS enabling handoverdirected to underlying network. This makes it possible to fully enabletraditional services also with I-HSPA network. The main difference whichneeds to be noted in planning is that supported UEs in I-HSPA areRelease 5 and 6 terminals. This means that the estimated user equipmentdensity in different cells can be based on actual traffic information as wellas marketing strategies. Like traditional networks, I-HSPA needs to coverindoor buildings and in some scenarios I-HSPA is intended as hot spotsolution in existing network, thus special requirements should be identifiedas an input for an accurate analysis. Similarly when operator has anexisting network, which can be used as an underlay for I-HSPA, all trafficinformation available through network management system can be usedas a base for detailed planning.

Characteristics of the radio network planning in I-HSPA are listed below.

Service environment:

. bit rates from tens of kbit/s up to many Mbit/s, variable data rate

. quality classes

. blocking probabilities

. delay sensitivity

. asymmetric uplink and downlink traffic

. common channel data traffic

Air interface:

. capacity and coverage coupled through interference margin andpower usage

. neighbour cells coupled through interference


06/03/2008


. receiver performance, depending on bit rate and environment

. soft handover

. fast power control

In standard WCDMA multiple network layers can be used to extend thenetwork capacity and/or coverage. In I-HSPA release 1 one carrier solutionis supported, but interworking is possible between WCDMA carriers andGSM layer, as I-HSPA enables CS services to be directed to underlyingWCDMA or GSM network.

Summary

In WCDMA network planning, a system approach to planning is essential.Radio network planning is based on dimensioning and its results. Radionetwork planning identifies specific site locations and refines theirconfigurations to suit the local environment and traffic profile.

Planning is divided into:

1. Link loss-based analysis for coverage planning.

2. WCDMA-based analysis for subsequent capacity planning.

Link loss-based coverage planning includes an evaluation of cell isolationto keep interference levels acceptable.

In the planning of detailed radio network configuration, base station siteconfigurations are planned according to the results of coverage andcapacity planning. This is an iterative process so that adjustments tocoverage and capacity calculations can be made after this phase iscomplete. To provide optimal coverage and capacity and serviceavailability, the interworking with underlying GSM/WCDMA networks mustbe planned.

Figure Detailed planning phases in I-HSPA radio network planning showsthe detailed planning phases.

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Figure 14. Detailed planning phases in I-HSPA radio network planning

The following steps list the planning phases. It is assumed that NetActPlanner is used for planning WCDMA radio network. NetAct Plannerprovides a flexible approach to planning and analysing different servicetypes by using a combination of service types, terminal types, and terminaldensity arrays. It supports Monte Carlo analysis for detailed coverage andcapacity planning

Steps

1. Plan coverage.

For detailed instructions, see Planning Coverage.

2. Plan downlink and uplink capacity.

Other RRM

Detailed planningDimensioning

Networkconfiguration

anddefinition

Requirementsand strategyfor coverage,quality andcapacity, per

service

PropagationmeasurementsCoverageprediction

Site acquisitionCoverageoptimisation

Capacitycalculation

Trafficdistribution,Service

distribution,Allowedblocking /queuing,Systemfeatures

Coverageplanning andsite selection

Parameterplanning

Handoverstrategies

Maximumnetworkloading

Externalinterferenceanalysis

IdentificationAdaptation

Area/cellspecific


06/03/2008


For more information, see Downlink capacity planning and Uplinkcapacity planning.

3. Plan detailed radio network configuration.

For detailed instructions, see Planning configuration.

4. Plan parameters for radio network.

For detailed instructions, see Planning parameters for radio network.

5. Plan GSM/WCDMA interworking

For more information, see CS interworking.

Expected outcome

The expected results of radio network planning are listed below.

. site selection

. base station configurations

. cell-specific parameters for RRM algorithms

. capacity and coverage analysis

. QoS analysis

6.3 Planning coverage

Purpose

The purpose of planning coverage is to identify site locations based on theservice coverage requirements and interference analysis. Planningcoverage combines the use of link budget calculations with path losspredictions and interference analysis. The objective of coverage is toobtain the ability of the network to ensure the availability of the services inthe entire service area.

This procedure explains how to plan coverage for I-HSPA. It is assumedthat the planning tool used is NetAct Planner. For information on theNetAct Planner, see NetAct Planner Product Documentation.

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Before you start

Note that you have to take into account the number of users in the roll-outphase and the estimated growth rate of capacity in the future.

Check that:

. Dimensioning has been completed to provide the initial, rapidevaluation of the possible network configuration.

. NetAct Planner is available.

. Propagation models have been defined on a per environment basis.

Input that is generally needed for planning coverage or capacity:

. Customer requirements

. Digital maps

. Traffic data, such as: census data, marketing studies, demographicinformation, and live traffic data from existing GSM/WCDMAnetworks

. Base station configuration information

. Existing site information

. Dimensioning output

. Field data measurements

. Antenna models

Interference analysis is already crucial in the coverage planning phase, itis needed for the loading and sensitivity analysis. In I-HSPA, coveragethreshold depends on the number of users and used bit rates in all cells.The coverage threshold is cell and service specific.

In WCDMA-based technology, all users in the same frequency share thesame interference and power resources in the Air interface. Each usercauses interference to other users and thus affects other users'transmission powers. These changes in turn cause further changes. Theinterference caused by the traffic load has to be taken into account incoverage planning. Therefore, coverage and capacity are coupled, in otherwords coverage depends on the supported capacity and vice versa.Simulations are iterative to find the optimum solution for both coverageand capacity.


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Characteristics of WCDMA-based (in FDD mode) networks mean thedynamic relationship between network load and coverage. Factors whichcontribute to the network loading include:

. Location and number of UEs

. Used bit rates in all cells

. Transmission power of each active mobile (dependent on theservices which subscribers are using, propagation environment, andinterference level)

Requirements for coverage are:

. Coverage regions

. Area type information

. Propagation conditions

Coverage planning is an iterative process with the other planning phases,especially with capacity planning, and the two should be consideredtogether. In order to predict coverage accurately, the system featuresassociated with I-HSPA must be taken into account in the networkmodelling process. In addition to different SNR requirements per eachservice of the multiservice environment, coverage also depends on loadcharacterisation, handover parametrization, and power control effects.

In I-HSPA, the following frequency bands are supported. Note that theavailability of the frequency bands is country- and operator specific.

Table 15. Supported frequency bands

Operating Band UL Frequencies

UE transmit, Node Breceive

DL Frequencies

UE receive, Node Btransmit

I 1920 – 1980 MHz 2110 –2170 MHz

II 1850 –1910 MHz 1930 –1990 MHz

III 1710-1785 MHz 1805-1880 MHz

IV 1710-1755 MHz 2110-2155 MHz

V 824 – 849 MHz 869-894 MHz

VIII 880 – 915 MHz 925 – 960 MHz

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A key difference between these bands in terms of coverage planning is the850/900 MHz frequency bands better wave propagation due to their loweroperating frequency. This leads to an increased cell range, enabling fewersites to be integrated compared to the standard 2100 MHz band andtherefore impacting the coverage planning. Typically, the cell range of the850/900 MHz bands is more than double compared to that of 2100 MHz.For instance, if a 900 MHz cell has a range of roughly 2 km, the 2100 MHzcell in identical environment has a range of 900 m. Therefore, in terms ofthe covered area, an 850/900 MHz cell is typically 4-5 times bigger for astandard macro cell.

Summary

Monte Carlo simulations used by the NetAct Planner serve as an effectivemethod to model the relationship between load and coverage. The MonteCarlo algorithm generates rasters for the desired period and area showingthe service level and load of specific cells. Analysis reports fromsimulations show the coverage and interference on the uplink anddownlink.

Coverage planning includes:

. Calculating link budgets

. Calculating path losses

. Analysing interference, Ec/Io

Figure I-HSPA path loss estimation shows basic path loss components,which are used to analyse and tune the coverage of the network.

Figure 15. I-HSPA path loss estimation

abc def

mnojklghi

pqrs tuv wxyz

+

Path loss and marginscell range calculation

Noise Figure

Transmit power

Antenna gain

Maximum pathloss margins

Antenna gain

Feeder losses

MHA usage

Configuration

Frequency

Noise Figure

Output power

# of carriers


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I-HSPA supports high performance of Flexi BTS, thus frequency, noisefigure are as in standard WCDMA Flexi BTS. I-HSPA release 1 supportsone carrier configuration.

Additional important tasks in coverage planning are antenna and sectorconfiguration. Flexi feederless solution creates additional gains for thealready high performance of I-HSPA coverage.

As I-HSPA supports 3GPP-specified terminals (Release 5 and 6) noadditional consideration is needed. Existing standard WCDMA networkcan be used to indicate the terminal penetration and support for thesereleases.

Path loss estimations and propagation models are used to calculate cellrange and coverage areas. Detailed network coverage planning requiresdigital maps and tuned propagation models for the Monte Carlo simulator.

Network coverage planning can be conducted with NetAct Planner.Common inputs to the Monte Carlo simulator are simulation parameters,cell parameters, cell - carrier assignment parameters, service parameters,and terminal parameters.

The numbered steps in the figure are explained in the steps below.

Figure 16. Phases of coverage planning in NetAct Planner

5. Compute path loss

6. Coverage and interference analysis

3. Configure withdefault configuration

Planningcapacity

1. Computeservice linkbudgets

2. Import / createsite candidates

4. Apply propagationmodel

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Steps

1. Compute service link budgets.

Calculate uplink (UL) and downlink (DL) link budgets per service andclutter class for both indoor and outdoor environments.

Further information

Calculating UL link budget is based on the transmit power capabilityof a mobile station, base station sensitivity, and the planned level ofmaximum UL cell load. The target in UL iteration is to allocatetransmission powers of the user equipment so that the interferencelevels and thus the base station sensitivity values converge. For ULboth associated DPCH and HSUPA will contribute to the noise rise.

Calculating DL link budget requires assumptions on the maximumtransmit power of a base station per traffic channel and on the levelof downlink cell load. The target in downlink iteration is to allocatethe correct BTS transmit power to each user equipment. As the DLcontains only HSDPA it is clear that all power will be used for onlyHSDPA services. HSDPA power is distributed among the users.

The limiting link budget is identified for each clutter class. Results ofthis may be used to define a set of thresholds for the path loss-basedcoverage analysis.

2. Import or create site candidates.

Sites should be placed as close as possible to areas with high trafficdensity. In this way transmit powers of base stations and userequipment are used efficiently and the interference level isminimised leading to maximum capacity.

Further information

Cell height should be selected according to the local radioenvironment, local site density, and cell heights of neighbouringcells. Otherwise umbrella coverage may occur generatinginterference across cells and unevenly sized cell dominance areas.

Macro cell layer should be planned to have good isolation from microcell layer. If WCDMA technology based equipment are co-sited withGSM equipment, antenna isolation of 30 dB is required.

3. Configure with default configuration.


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Configure each site candidate with the default configuration.

Further information

Default parameter sets should be defined for each environment.These sets contain the initial cell configuration. This configuration isthen refined as the detailed planning process continues. Once thewhole planning process is complete, feedback from the process canbe used to update the default parameter set.

4. Apply propagation model.

Propagation models should be defined on a per environment basis.This is a prerequisite to the I-HSPA radio planning process. Applysuitable propagation model to each cell.

Further information

NetAct Planner uses the following propagation models:. Standard macrocell is based on the ETSI Hata model and is

valid for frequencies from 150 MHz to 2 GHz. It is typicallycalibrated to 8 dB standard deviation. It is used for sites inenvironments where the distance from the site is greater thanapproximately 500 m, where base station antenna heights arein the range of 15 to 200 m, and where receiver heights are inthe range of 1 to 10 m.

. Standard microcell is based on a pseudo ray-tracingtechnique. It is typically calibrated to 8 dB standard deviation.It is used in sites found in urban environments, for propagationin the 'urban canyon' environments, and for in-buildingcoverage.

. Nokia Siemens Networks propagation models are based onthe ETSI models and are valid for frequencies between 150 to2000 MHz. They are typically calibrated to 7 dB standarddeviation. They are used for sites where the distance range isbetween 10 m to 100 km, where base station antenna heightsare in the range of 4 to 200 m and where receiver heights arein the range of 1 to 10 m. They are used in macro cells andurban small cells where propagation path is mainly over theroof tops.

5. Compute path loss.

Compute path loss for each cell within the area being planned.

Further information

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The dynamic range of the calculations should be large enough toensure that the minimum received signal strength, when the basestation is transmitting at full power, is 10 dB below the UE'ssensitivity for a speech service. 10 dB is a margin of sensitivity forspeech set up in the tool.

6. Apply coverage and interference analysis.

Identify areas with excessive or insufficient coverage and improvecoverage by optimizing or by removing and adding cells. Thenidentify areas with poor cell isolation (high interference) and poordominance, and optimize cells further until you achieve acceptablecoverage.

Further information

Areas with excessive coverage are likely to have high levels ofintercell interference and a low system capacity.

Optimization is a preferred way to improve coverage instead ofadding or removing cells. Optimization at this stage consists of theadjustment of antenna configuration. Cells should be removed oradded only if the coverage area cannot be improved by optimization.Optimization of the antenna configuration is also a preferred way toimprove Ec/Io ratio and dominance areas. Coverage should bemaintained while optimizing the Ec/Io ratio and cell dominance.

7. If planning coverage meets the required targets

Then

Move to Planning capacity.

Else

Apply coverage and interference analysis.

Expected outcome

. Set of candidate sites and their locations.

. Initial cell configurations of candidate base station sites.

. Base station parameters.


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6.4 Planning capacity

Purpose

The purpose of planning capacity in I-HSPA is to evaluate the optimal siteconfiguration in terms of pilot and common control channel powers,throughput, and soft handover parameter set in uplink. The objective forcapacity is to support the subscriber traffic with sufficiently low blockingand delay.

This procedure explains how to plan capacity for I-HSPA. The similarcapacity planning approach can be used for traditional HSPA networksand I-HSPA. It is assumed that the planning tool used is NetAct Planner.For information on NetAct Planner, see NetAct Planner ProductDocumentation.

Before you start

Check that:

. Dimensioning has been completed.

. Planning coverage has been completed.

. NetAct Planner is available.

. Traffic Raster is available for Monte Carlo simulator.

Input that is generally needed for planning capacity contains also samecomponent as coverage planning, still some parts are with higher focus.One clear prerequisite is to have coverage planning done before capacityplanning with accurate site location. Following parts are needed incapacity planning:

. Customer requirements, for example features and strategies.

. Traffic data, such as: census data, marketing studies, demographicinformation and live traffic data from existing WCDMA/GSMnetworks.

. Existing network configuration and measurement/traffic data.

. Dimensioning output.

In I-HSPA the focus is on detailed capacity planning, when compared to atraditional GSM network. Traditional WCDMA network combines bothcapacity and coverage, while I-HSPA focuses on packet service capacityand not so much in basic coverage planning. This depends on the operatorstrategy.

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As in traditional WCDMA, in I-HSPA the capacity of a cell affects thecoverage of the cell. The cell breathes as the amount of users varies. Tokeep the quality of services in suitable levels, admission control, packetscheduling and handover mechanisms are used. In I-HSPA the CS serviceis made available through CS enabling handover.

The importance of capacity increases when the network expands and theamount of traffic grows. Each cell should be loaded relatively equally andin a way that there is room for future growth.

Requirements for capacity:

. Subscriber growth forecast

. Traffic density information

. HSDPA and HSUPA feature sets

. Traffic distribution among Release 5 and Release 6 terminals

Capacity planning is an iterative process with the other planning phases,especially with coverage planning, and the two should be consideredtogether.

Summary

Ensuring that the pilot and common control channels do not consumeexcessive quantities of the cells transmit power results in a greater shareof the power being available to the traffic channels. In uplink optimizing thelevel of possible soft handovers ensures that the transmit power assignedto the best server links is maximised, while the service coverage ismaintained at cell edges. These are especially important in downlinkcapacity limited scenarios.

Cell capacity is determined by:

. Site location

. Closeness of the neighbouring cells

. Geographic distribution of the traffic loading the network


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Figure 17. Planning capacity with NetAct Planner

Tasks described in Figure Planning capacity with NetAct Planner areexplained in the steps below.

Steps

1. Plan and optimize coverage.

The objective of optimizing coverage is to ensure that the pilot Ec/Iorequirement is achieved at the cell edge, while minimising the areasof overlapping cells. Pilot power parameter optimization is required,as it directly controls the power of the other common controlchannels in the cell. Pilot power optimization should normally bedone on area level, not on individual cell level.

Further information

The common downlink pilot channel is used by the mobile stationsfor synchronization and channel estimation. Assigning excessivequantities of pilot power reduces the system capacity when there isless power available to the traffic channels.

Capacity planning setup and simulation

Define I-HSPA Bearers-HSDPA/HSUPA bearers-HSDPA coding rates-Bit rates-Eb/No target-HSUPA Power controlland Soft handover para-meters

Define I-HSPA services-Packet services-HSDPA support-HSUPA SHO-QoS parameters

Create I-HSPA terminals-Set terminal parameters-UMTS support-HSDPA support-HSUPA support

Create UMTS celland set I-HSPAparameters-Assign carrier-Set cell parameters-Set power para-meters for HSDPA-Set Noise rise forHSUPA

Setup terminals-Associate bearers with services and them with terminal types-Spread the terminals

RUN static analysis or Monte Carlo simulatorView array outputs and reports

Coverage planning and optimisation

Validate capacity planning with realistic traffic

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2. Set up NetAct Planner parameters.

NetAct contains multiple parameters which need to be set beforemaking capacity estimation. For example, the following parametersneed to be set:. Defining bearer parameters, including Eb/Nos, bit rates,

coding rates, power and handover parameters.. Defining service parameters. Creating terminals. Creating cells and setting I-HSPA specific parameters. Spread terminals

Simulation can be used to estimate network capacity within wantedservice distribution. In I-HSPA also handover affects systemperformance. Planning tool can be used also when evaluatingfunctionality of hard handover and CS enabling handover to othersystems. A feedback loop between pilot power and handoveroptimizing is used to balance the dependence of handover areas onthe pilot powers.

Further information

NetAct Planner parameters affect system performance, thus theyneed to be as realistic as possible. Capacity simulation can be usedto identify possible problem areas in the network. For example,areas of poor quality and low service availability. These problemscan be solved already with small changes in antenna direction or tilt.

3. Validate with realistic traffic.

Validate network with realistic traffic. Load the network with realistictraffic expectation and evaluate the sufficiency of the systemcapacity.

Further information

The traffic expectation should be modelled for multiple busy hoursthroughout the day and busy days throughout the week. A WCDMAanalysis should be completed for each traffic profile. Monte Carlosimulations are used in evaluation of traffic. Blocking performanceshould be used as an indication of the sufficiency of the systemcapacity.


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Expected outcome

. Number and location of the base station sites

. Configuration of the base station sites

. Capacity and coverage of the base station sites per service

. Throughputs in uplink and downlink

. Number of users per service

. Loading

. Uplink soft handover probability

6.5 Downlink capacity planning

The HSDPA performance depends heavily on the radio networkpropagation and C/I conditions. Therefore, it is important to plan the radionetwork carefully to ensure good HSDPA performance. To limit theinterference from the neighbouring sites, the network should consist ofclear cell dominance areas. High-rise overlay sites on the same frequencyshould also be avoided.

All power in downlink is allocated for HSDPA, therefore there is no need forextensive R99 DCH non-real- and real-time traffic estimation. Likewise thecoverage and capacity dimensioning is capacity tightly connected withpower, feature and environment characteristics to the performance, as wellas to Node B and other interface processing capacity.

Figure Main factors affecting HSDPA performance shows the main factorsaffecting HSDPA performance.

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Figure 18. Main factors affecting HSDPA performance

There are several designs for HSDPA coverage with I-HSPA. Alsopossible CS service layering between existing GSM or WCDMA networkneeds to be considered. Depending on the business strategy, there are atleast the following options to consider:

. Overall or hotspot coverage

Hotspot coverage requires less investment but makes I-HSPAmobility management more challenging. It is therefore morecommon to enable I-HSPA on a cluster basis.

. Indoor solutions

Indoor solutions can potentially offer high average HSDPAthroughput. The throughput performance depends on the SINRconditions in the same way as it does for macro cells. The HSDPArequirements should be taken into account when designing anindoor solution.

The indoor solutions may use either an active or passive DAS. Anactive DAS should be selected if the passive DAS losses arerelatively high, that is, if 18 dBm cannot be maintained at eachremote antenna connector.

Careful radio network planning enablesgood HSDPA performance

Network elements should be dimensionedto limit the HSDPA performance as little aspossible

HSDPA PERFORMANCEAvg. cell throughputAvg. user throughputMin. user throughput atcell edge

BTS processing capacity

HSDPA power allocationHSDPA features

-Modulation-Scheduling

UE categoryPropagation environmentInterference from other cells


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The indoor solution HSDPA link budget should take into account thefollowing:. Low downlink transmit power radiated by the DAS. High orthogonality reducing the level of the cell’s interference. Lack of soft handover gain in uplink. No fast fading margin due to no power control. Reduced slow fading margin. Potentially high level of inter-cell interference from the macro

cell layer

. Handover strategies

There are multiple possibilities to either enable normal handover orutilize only hard handover. This has an impact on network capacityrequirements and is connected to operator deployment strategy.

. Layering options

Although I-HSPA release 1 supports one carrier deployment, a twolayer option needs consideration. CS enabling handover to existingsystem complements I-HSPA, which requires detailed considerationof I-HSPA implementation within the existing coverage.

In some networks there is no need to consider layering aspect betweenexisting network and I-HSPA. Commonly this means also wider coveragewith I-HSPA to enable mobility. As I-HSPA enables multiple possibilities toeither simplify or complex the network functionality and handling.

As the mentioned features have high impact on HSDPA performance, thefeature sets need detailed consideration within the detailed downlinkcapacity evaluation. Also UE type will have impact on downlinkperformance.

6.6 Uplink capacity planning

The purpose of uplink capacity planning is to allow the deployment of theHSDPA associated UL DPCH and HSUPA feature sets at the plannedperformance target, while minimizing the impact degradation on eithertraffic. HSDPA associated UL DPCH is supported by 3GPP Release 5terminals and HSUPA by 3GPP Release 6 terminals. For I-HSPA theterminal penetration as well as UE sales strategies need to be consideredwhen planning uplink capacity.

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HSUPA can be used to increase both uplink total cell throughput anduplink individual connection throughput. HSUPA can be supported, forexample, in specific target locations to improve the end-user experience,when ever there are relatively high quantities of uplink traffic. Support ofHSUPA increases the efficiency of the uplink Air interface and can be usedto relieve congestion. This is only effective if the penetration of HSUPAterminals is relatively high. It is expected that the initial deployment ofHSUPA will be focused upon offering an improved end-user experience.

I-HSPA deployment scenarios need to consider the share of DPCH andHSUPA traffic. This means that the same planning and estimation appliesto all outdoor macrocell coverage areas in urban, suburban and ruralareas. Indoor solution capacity depends on the share of terminals whichsupport either DPCH or HSUPA in uplink.

Downlink capacity is dedicated to HSDPA, but in uplink capacity isdistributed between DPCH and HSUPA. From the point of view of BTSresources, this does not generate problems as the channel elements aredynamically shared between DPCH and HSUPA.

When I-HSPA is deployed by a greenfield operator without existingnetwork, the main focus is to check the radio dimensioning results foruplink. These should provide the operator strategies. In detailed planningthe special cases, such as indoor solutions, need to be analysedthoroughly.

High data rate services are well suited for indoor deployments. Indoorsolutions can be designed with either active or passive DistributedAntenna Systems (DAS). The choice between an active and passive DAStends to depend upon the size of the indoor solution, that is, larger indoorsolutions require an active DAS. The performance of HSUPA is dependantupon the performance of the Node B receiver and the associated uplinkEb/No requirements.

Uplink receive diversity is an effective way to decrease the uplink Eb/Norequirement and increase the total uplink cell throughput. Macrocells tendto have uplink receive diversity configured as standard. However, indoorsolutions may not be deployed with uplink receive diversity. When HSUPAis introduced, additional consideration should be given to using uplinkreceive diversity.

In case of an existing GSM/WCDMA network, the uplink capacity planningincludes following tasks:


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. Monitoring and analysing existing GSM and/or WCDMA networkperformance

If available, OSS counters can be used to determine current networktraffic on a per cell or per BTS level. Otherwise networkdimensioning and simulation results can be used. The resources toconsider in the analysis are:. Air interface capacity. BTS processing capacity. Transport capacity

. Analysing the existing terminal penetration and marketing strategies

. Defining the uplink performance targets and deployment strategy

The total cell throughput offered by HSUPA is dependant upon theallowed uplink interference margin, which is the total of DPCH andHSUPA traffic. Achieving the required performance target requiresconsidering the load share.

It is likely that in location where HSUPA is used there will be atendency to increase the maximum allowed increase in uplinkinterference, that is, UE will have to increase their transmit powers tocompensate for an increased uplink interference floor. The impact ofan increased uplink interference floor should be evaluated as part ofthe link budget analysis in the dimensioning phase. The maximumallowed increase in the uplink interference floor can be managedusing radio resource management (RRM) parameters.

6.7 Planning configuration

Purpose

The purpose of planning detailed radio network configuration is to plan sitelocations and base station configurations, to select antennas and to defineantenna directions to meet the planned capacity, coverage, and quality ofservice requirements.

Before you start

Check that:

. Estimating initial network configuration has been completed andresults are available.

. NetAct Planner and other planning tools are available.

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The solution for detailed radio network configuration should provide asmuch of the coverage and capacity performance as possible. The solutionshould also be able to accommodate capacity upgrades, be possible toconstruct and meet all building requirements set by authorities.

The selection of base stations and antennas is dependent on therequirements on capacity and coverage of sites. Ideally, site selection isbased on the network analysis with planned load and traffic serviceportfolio. Possible methods for improving radio network configuration andinterference control mechanisms are:

. Mast head amplifiers

. Using diversity reception

. Sectorization

. Proper antenna selection

. Antenna tilting

. Suitable base station configuration

. Suitable power amplifier and baseband capacity licenses

Planning detailed radio network configuration is an iterative process withcoverage and capacity planning, and suitable sites are selected based onthe results of those.

Summary

When acceptable sites have been found with suitable coverage, capacity,and quality properties, planning detailed radio network configuration takesplace.

The detailed base station configuration includes also calculation of neededchannel elements, which impacts on number of system modules. Similarlyamount of sectors impacts on number of RF modules. In this phase alsoantenna line and base station-related parameters are planned anddefined.

Steps

1. Plan site locations.

Planning locations for base station sites is an iterative process withcoverage planning. Potential site candidates are defined duringcoverage analysis to find suitable sites that can be acquired by theoperator. Commonly sites are first selected from existing sites, if


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possible, but if their location is not suitable for meeting coverage andcapacity requirements, completely new sites are selected. When theselected sites meet the coverage, capacity and quality requirements,the coverage plan is updated and it is possible to start planning theconfigurations of base stations for the sites.

2. Plan BTS configuration.

Planning base station configuration includes defining the number ofsectors and channels. You must also define the output power ofantenna connectors. You must plan the number of Radio andSystem Modules to meet the capacity and coverage requirements.Similarly the used frequency has to be selected.

I-HSPA release 1 supports Flexi WCDMA BTS. Within the Flexi BTSthe supported configurations are Omni, 1+1 and 1+1+1. FlexiWCMDA BTS for I-HSPA supports different power amplifiers. 20 and40 Watts power amplifiers are most commonly used for macro celldeployment. Flexi WCMDA BTS with I-HSPA Adapter supports 8Watts power amplifier, which can be used in micro and indoorsolutions. Flexi WCDMA BTS supports two system modules. Thecapacity of one system module can handle low and medium trafficcapacity requirements and two system modules can handle hightraffic capacity requirements.

Flexi WCDMA BTS with I-HSPA supports multiple frequencies.Supported frequencies are 2000MHz S-Band carrier and 850, 900,1700, 1800, 2100M carriers. The frequency affects Air interfaceperformance and thus also to the dimensioning of Air interface. Thefrequency also affects the configuration planning where main issuesare frequency support of antenna and antenna line. For example,antenna types support different frequencies with different gains aswell as cable losses varies among the frequencies.

3. Plan antenna line.

Planning antenna line includes defining the number and type ofantennas and selecting mast head amplifiers (MHA), selectingnumber and output power of the power amplifiers, cabling solutions,and connectors.

The usage of multiple receive paths (antennas or polarisations) inBTS, for example, UL antenna diversity, improves the UL coverageand capacity. The MHA compensates feeder losses in UL andimproves UL coverage. Cell coverage can be focused and controlledby antenna down tilting.

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4. Define BTS-related parameters.

This phase includes planning DL power parameters for control (forexample, pilot power) and dedicated channels. Scrambling codeplanning is also needed.

For more information, see Planning parameters for radio network.

6.8 Planning parameters for radio network

Purpose

The purpose of planning parameters is to optimize the usage of radionetwork and to fully utilize the planned coverage and capacity. There areparameters related to radio resource management, and by tuning those itis possible to use the capacity to the fullest without compromising thequality of services.

Radio resource management is responsible for efficient utilization of theAir interface resources and is needed to maximize the radio performance.

It is used for the following purposes:

. To guarantee the quality of service: block error ratio (BLER) anddelay

. To maintain the planned coverage for each service

. To ensure the planned capacity with low blocking or packet loss

. To optimize the use of capacity

. To utilize the hardware to the maximum

Planning radio network is an iterative process and parameters are plannedtogether with coverage and capacity planning. The parameters offer aninitial configuration of the network and the parameters could be set in thebeginning to offer 'loose' limits and admission to all users. The parameterscould be improved later during network optimization to manage thecapacity-quality trade-off.

Some of the most important parameters that are defined during this phaseare the following:


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. Power control parameters: defining how transmission power controlmechanisms are used and ensure that the signal level required atthe transmitter and the receiver is sufficient to maintain adequatequality.

. Handover control parameters: control how handover procedures areperformed.

. Admission control, load control and packet scheduling parameters:manage available non-real time resources in I-HSPA and are part ofthe load control functionality.

Once the system is operational and operators have information availableon the performance of their networks, the information can be used inoptimizing the I-HSPA network.

Steps

1. Plan power control parameters.

Power control in I-HSPA concerns mainly uplink. In downlink, powercontrol is used for control channels. Power control parameters areneeded to provide services to the largest possible number ofsubscribers using the smallest amount of power, while keepingcoverage and quality of service at the optimum level.

Power control provides protection against large changes inshadowing, immediate response for fast changes in signal levelsand interference levels (SIR). Power control is also needed to copewith the near far problem and to recover as fast as possible a signal-to-interference ratio (SIR) close to the target SIR after eachtransmission gap in compressed mode

Power causes interference to others in I-HSPA, thus power control isnecessary to limit the interference.

Further information

Fast power control is vital for system performance. Its purpose is tocontrol the Tx and Rx powers. It is important to keep the Rx powersin uplink on the same level. This leads to minimised interference andsmall power consumption.

Closed-loop power control compares the measured signal-to-interference ratio (SIR) with the targeted SIR. Then it transmits apower control command accordingly in uplink or downlink at 0.667ms interval. It makes Eb/N0 requirements lower. Closed loop power

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control equalises received powers at a base station in uplink to avoidthe near-far effect. It introduces interference peaks in thetransmission, especially if the user equipment is moving slowly, asthe fast fading can be followed by fast power control.

Open loop power control estimates the needed power based on pathloss and interference measurements in a random access channel(RACH). UE uses the uplink open loop PC algorithm also forestimating the initial transmission power of the uplink DPCCH.

At the radio access bearer (RAB) setup the uplink outer loop PCController gets the following bearer and radio link-specificparameters from the Admission Control:. Radio link-specific parameters:

. Initial, minimum and maximum UL SIR Target.

. Initial, maximum and minimum DL power. Bearer-specific parameters for each dedicated channel:

. Initial planned Eb/No target

. BLER target (for low quality bearers)

Common channel powers need careful planning, as commonchannel power planning is vital for good coverage and capacity.Common channel powers are relatively large compared to dedicatedchannel powers. Common channel powers are not power-controlledsince they must be decoded everywhere in the cell area. SecondaryCCPCH carrying FACH transport channel is the only downlinkcommon physical channel that can use power control. Transmissionpower of the FACH transport channel is controlled by sending qualityinformation in RACH messages.

The parameter set associated with allocating transmit power to theHSUPA downlink channels are relative to the CPICH. Default valuesfor the E-HICH and E-RGCH represent the transmit power allocatedto a single signature sequence. Each HSUPA connection isallocated a single E-HICH signature sequence and a single E-RGCHsignature sequence. The transmit power requirement accumulatesas multiple connections become active.

2. Plan handover control parameters.

Plan parameters related to handover triggering and measurementsfor both soft and hard handovers. Handovers can be triggered bypilot signal level and quality, radio link transmit power, connectionquality and with load- and service-based handovers also due to usedservice type and/or cell load. Planning of parameters controlling UE


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mobility, when there is no dedicated channel allocation, can be alsoincluded in handover control planning. These cell selection and re-selection parameters specify the criteria used by the terminal tomake the selection of the cell where it is camping.

HSDPA mobility is a standard feature in I-HSPA. Serving HS-DSCHcell change and SHO of the associated DPCH is not an optionalfeature in I-HSPA.

Further information

There are two main handover types.

Soft handover is either a soft or softer handover. UE can besimultaneously connected to multiple base stations. This requires anIur interface in I-HSPA.

The objectives of soft handover are:. optimal fast power control so that the user equipment is always

connected to the strongest cells in an area. seamless handover without disconnection of the user

equipment

The probability of a soft handover is between 0 to 30% as SHO mayeven be neglected in I-HSPA. Soft handovers increase transmissioncapacity need in Iur interface and consume more channel elements.

Softer handover provides additional diversity gain. Probability of asofter handover is between 5-10% and it sets no extra transmissionrequirements for Iub interface. In both soft and softer handover youneed two or more active set sizes.

Hard handover is either an intra-frequency handover or inter-systemhandover. Intra-frequency handover is controlled by I-HSPA Adapter.Inter-frequency handover is a network evaluated handover andcontrolled by I-HSPA Adapter.

For more information on handovers in I-HSPA, see Mobilityscenarios, HSDPA mobility handling and HSUPA features andparameters.

3. Plan packet scheduling parameters.

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Plan packet scheduling parameters that are used to maximizecapacity. The main task of the packet scheduler is to estimate theavailable capacity and fill the system up to maximum loading whilestill ensuring the required quality of service for non-real time traffic.The packet scheduler also performs overload actions to the non-realtime connection to keep the load below the target load level. Thepacket scheduler can be configured to prioritise the selectedconnections based on the allocated QoS level of the connection.

Further information

Packet scheduling takes care of scheduling radio resources in bothuplink and downlink. It should keep the interference caused to otherusers as small as possible. Packet scheduling is used for bothdedicated and common control transport channels (RACH/FACH).Packet scheduling determines the time when a packet is sent andthe bit rate used. The decision to send a requested packet is basedon the measured PrxTotal in uplink or PtxTotal in downlink and onthe estimated loading of the requested new service.

4. Plan admission and load control parameters.

Admission control sets initial downlink transmission power for thechannel, power control range, and many other parameters, such astransport format set.

In uplink the measured, total received wideband interference powerindicates the traffic load of the radio resources. In uplink, the totalreceived power is the function of the maximum interference receivedin the wideband spectrum.

The cell-based RRM load control includes the following load statusreports and load control parameters:. Parameters related to the load control functionality. Cell load status, which includes the load measurement results. Estimated cell load

5. Plan scrambling codes.

Downlink scrambling codes are needed for the synchronizationbetween UE and BTS for the cell search and identificationprocedures during the call set up and handover.

Plan an own scrambling code for each cell to prevent codes frominterfering with the other codes. All the cells that the UE is able tomeasure in one location should have different scrambling codes.


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Further information

Allocating the downlink scrambling code groups is part of theplanning process. There are 512 scrambling codes used, 8 in eachof the 64 code groups. The reuse factor could be 64 since there are64 code groups. The scrambling code group planning for eachcarrier layer is independent, the same codes could be used.

The scrambling code planning can follow different rules. One is thatthe neighbour cell list (NLC), which contains the scrambling codes,should contain as few code groups as possible. The alternative ruleis that the NLC should contain all of its scrambling codes fromdifferent groups. The main planning criterion is that the separationbetween two cells using the same scrambling code must be largeenough.

The following is one recommendation for planning scrambling codesin all neighbour sets, in all environments, and applicable to Nokiauser equipment only:. Minimise the number of used code groups in the neighbour

set.. Maximise the number of codes per group in the neighbour set.

A large number of neighbours increases the cell search time forexample in urban areas. The size of the neighbour set should belarge enough to include all useful candidates. At the same time itshould be as small as possible to maintain a fast synchronizationprocess.

Expected outcome

. Power control parameters

. Handover control parameters

. Packet scheduling parameters

. Admission and load control parameters

. Scrambling codes

6.9 Mobility scenarios

The following provides a detailed description of the mobility scenariodifferences between I-HSPA and traditional WCDMA/HSDPA. Thescenarios are split by the three typical handover type classes:

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. Intra-system

. Inter-system

. Inter-RAT

Figure I-HSPA mobility scenario overview shows an overview of the I-HSPA intra- and WCDMA/HSDPA inter-system handover scenarios aswell as the involved network elements and (optional) interfaces.

Figure 19. I-HSPA mobility scenario overview

Intra-system handover within I-HSPA

In the intra-system handover all valid WCDMA handover types areapplicable. Softer handover, soft handover and hard handover arepossible mobility scenarios for the intra-system handover.

RNC

MSC-S+MGW+NVS

SGSN

GGSN

IMS: Video sharingVolP, IPCentrex

Connect &ConnectivityInternet +Intranets

WCDMA BTS

I-HSPA

I-HSPA

abc def

mnojklghi

pqrs tuv wxyz

+

Inter-systemHandover tonon-I-HSPA

Intra-systemHandover

within I-HSPA


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As in traditional WCDMA systems, also in I-HSPA systems the availabilityof an Iur connection between the I-HSPA adapters is required for thesupport of soft handover scenarios. Lack of Iur connection will result inhard handovers in all inter-adapter mobility scenarios. Softer handoverswithin the cells of the same I-HSPA Adapter are valid scenarios alsowithout the availability of Iur connections.

In order to avoid a high transport load on the Iur, each I-HSPA intra-systemhandover will result in a SRNS Relocation through SGSN.

Inter-system handover between I-HSPA and traditional WCDMAsystems

If there is no Iur connection between traditional 3GPP RNCs and I-HSPAAdapters, and Iu-r is the only available interface between RNCs and I-HSPA Adapters, the inter-system handover between I-HSPA andtraditional 3GPP systems is always a hard handover.

As all inter-system handovers use the existing 3GPP standard interfaces,the handovers between I-HSPA and a traditional WCDMA system aresimilar to standard SRNC relocations between Adapters and RNCs.

The handover of CS service requests from I-HSPA to traditional WCDMAsystems is a special form of inter-system handover. When a mobile stationrequests CS service from I-HSPA it camped on, I-HSPA forwards therequest to a traditional WCDMA or GSM system. An Iu-CS signallingconnection to the MSC ensures the paging support for CS services.

Roaming

Independent from all mobility scenarios described above, normal globalroaming is not affected in I-HSPA. All normal roaming scenarios are alsovalid for an I-HSPA user in any other traditional WCDMA or even GSMnetwork.

I-HSPA makes use of standard U-SIM user equipment. Global roaming isonly limited by service agreements between the various system operators.

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6.10 CS interworking

I-HSPA is a PS-only solution, but it can be complemented with CSservices, which are provided by underlying networks, such as traditionalWCDMA or GSM networks. I-HSPA redirects UE to traditional WCDMA orGSM networks when UE requests CS services, which require CS RABs. I-HSPA Node B (I-HSPA Adapter) has Iu-CS signaling connection to MSC toensure that paging can be supported for CS services.

CSEnHOwithIuCS (CS Enabling handover solution with Iu-CS) parameterdefines the use of Iu-CS based handover of CS calls to WCDMA or GSMnetworks. If this parameter is enabled, the Iu-CS solution for redirection/handover of UE is used in case of a CS call attempt. If this parameter isdisabled, the solution without Iu-CS is used.

If Iu-CS is enabled, multiple parameters need to be defined under Iu-CSparameters.

CSRedirWaitTimer (CS Enabling handover re-attempt supervision timer)parameter: when UE attempts a CS call, I-HSPA Adapter immediatelycommands the UE to go to a neighboring WCDMA/GSM cell. I-HSPAAdapter waits for a time duration defined by this management parameterbefore releasing resources and context for the redirected UE. In case theUE comes back within this time, it is again redirected out of I-HSPA RAN,but no more supervision is done. In effect this timer is used for given theUE one more chance after an unsuccessful redirection. If value of the timeris set to zero, then this supervision is not used, that is, once UE isredirected, its context is cleared immediately.

6.11 URA planning and paging

URA planning

In I-HSPA release 1, a UTRAN registration area (URA) consists ofmaximum 7 I-HSPA Adapters. Thus each I-HSPA Adapter can have amaximum of 6 neighboring I-HSPA Adapters. Figure UTRAN registrationarea shows the I-HSPA Adapter areas in URA.


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Figure 20. UTRAN registration area

There can be up to seven different URAs defined for each cell. The firstURA ID in the URA-list of the cell is a primary URA. The primary URA isassigned to the UE in the cell when the UE is registered on the URA. Therest of the URA IDs in the URA-list are secondary URAs (URA IDs of theneighboring / overlapping URAs, to which the cell belongs to), which arebroadcast on BCH of this cell.

URAs may be hierarchical to avoid excessive signalling. This means thatseveral URA identifiers may be broadcast in one cell and that different UEsin one cell may reside in different URAs. UE in URA_PCH state shallalways have only one valid URA ID.

The UE is moved to the URA_PCH state to avoid frequent cell updatesdue to cell reselection. This helps in avoiding allocating resources for theUE, which is fast moving and is not in any active calls. It also helps to saveresources for other UEs that may be in more active mode.

In this state, the UE initiates a URA updating procedure on URA change.

Iur

Iur

Iur

IurIur

Iur

I-HSPA URA_PCH area I-HSPA Adapter area

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URA paging

In case of DL PS activity, UTRAN initiates a paging procedure to locate theUE in URA_PCH state. RNSAP signalling entity (Iur) uses RNSAP:PAGING REQUESTservice to send paging message to the neighboring I-HSPA Adapters. The paging message is sent only to I-HSPA Adapters thatconstitute the current URA of the UE.

Figure URA paging shows how the paging message is sent to I-HSPAAdapters.

Figure 21. URA paging

When the UE is in URA_PCH mode, even though the serving I-HSPAAdapter does not know the exact location, the SGSN still has theconnection to the I-HSPA Adapter for the UE. Hence, when the UE getssome data from the CN, (for example, UE receives some data from theInternet server) the serving I-HSPA Adapter pages for the UE to establishthe resources again to facilitate data transfer.

Though the serving I-HSPA Adapter knows the UE’s URA ID, it does notknow the exact location of the UE even to the URA level due tooverlapping URA IDs being used. The reason for this is that every cell mayhave up to 7 URA IDs. Hence, the serving I-HSPA Adapter needs to sendthe paging message to the cells under its command. It also needs to

Iur

Iur

Iur

IurIur

Iur

Data to UE from IuPS

Paging to own cells and page over Iur


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propagate the paging message to the (possibly 6) neighboring I-HSPAAdapters, to which the I-HSPA Adapter has Iur connections to. Thus, thepaging message is spread across an area covered by up to 7 I-HSPAAdapters.

URA_PCH support impact and benefits in I-HSPA

With the introduction of the URA_PCH state, transitions from CELL_DCH/CELL_FACH/CELL_PCH to URA_PCH will be supported. This will behelpful in reducing the number of cell updates and hence reduce batteryconsumption of the mobile due to RACH procedures. URA Updateprocedure will be supported to notify the UTRAN of the change in the URA.

6.12 LAC and RAC planning

Location Areas (LA) and Routing Areas (RA) are used by the core networkto track UE locations. LA updates (LAU) and RA updates (RAU) can beeither normal (resulting from mobility) or periodic.

In I-HSPA SGSN databuild defines the periodic LAU and RAU timersrespectively. The minimum possible size of a LA is a single cell. Themaximum possible size of a LA is the collection of cells connected to asingle VLR. Similarly the minimum possible size of a RA is a single cell. ARA is always contained within a single LA.

If LA and RA are planned to be relatively large then they mayaccommodate large numbers of UE, thus the quantity of paging trafficincreases. If location areas are planned to be relatively small, there will bean increase in the quantity of signalling generated by normal LA updates.Some UE have poor call establishment performance when attempting toestablish a call at the same time as completing a LA or RA update. Thereis also a short period of time during which a UE cannot be paged whencompleting a normal LA or RA update.

I-HSPA operators with existing GSM or WCDMA networks may use thesame location area codes and the same routing area codes. Thedrawbacks are an increased quantity of paging on both systems and arequirement to co-ordinate to ensure different cell identities. Service areascan be used to inform the core network of a UE’s location.

Location areas and routing areas should be defined to be the same. Theminimum size should be the collection of single site. Existing GSM orWCDMA location area and routing area boundaries should be used as abasis for defining I-HSPA location area and routing area boundaries, but

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noting that there is only one I-HSPA Adapter per site. I-HSPA is similar totraditional networks in the sense that location areas and routing areasshould not run close to and parallel to neither major roads nor railways.Likewise, boundaries should not traverse dense subscriber areas.

LAC and RAC planning requires special consideration when CS serviceenabled handover is used between GSM or WCDMA network.

6.13 HSDPA features and parameters

6.13.1 HSDPA resource management

HSDPA resource management controls the allocation of HS-PDSCH/HS-SCCH codes and allocation of downlink power resources.

The features in HSDPA Basic functionality consist of QPSK and 5 HS-PDSCH codes. Additional basic characteristics of the feature are listedbelow:

. Maximum number of HSDPA users per BTS is 16.

. Maximum HS-SCCH codes per cell is 1.

. Maximum HS-PDSCH codes per UE is 5.

. Up to 3 cells per BTS can be enabled for HSDPA.

HSDPA utilizes dynamic resource allocation. BTS allocates all availablepower until BTS maximum Tx power, which is the power defined asminimum of the management parameter PtxCellMax and the BTScapability (indicated by MaxDLPowerCapability). PtxCellMax can beused to limit the total power of the base station which limits also thedownlink noise rise and enhances performance at cell edge areas.

The optional minimum UL bit rate for HSDPA return channel can beactivated with HSDPA16KBPSReturnChannel parameter and by setting theHSDPAminAllowedBitrateUL to minimum value. This is recommendedwhen the estimated or measured number of HSDPA users is high, as itgives the PS possibility to release UL resources by decreasing the radiobearer bit rate in congestion situations, especially for UL HW resources.


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Optional feature set includes the possibility to enable the usage of morethan 5 HS-PDSCH codes in a cell. This is made through HSDPA 15 Codes(HSDPA15Codes) feature. Similarly with code multiplexing feature morethan 1 user can be served in same TTI. Additionally to these alsomaximum number of users can be increased up to 48 users per cell.

6.13.2 Maximum bit rate of HS-DSCH MAC-d flow

The maximum user bit rate of the HS-DSCH MAC-d flow used in theresource reservation for the HS-DSCH MAC-d flow is limited by themaximum bit rate based on User Equipment (UE) capability, the value ofmanagement parameter MaxBitRateNRTMACDFlow and by the maximumbit rate in RAB QoS parameters.

The value of MaxBitRateNRTMACDFlow does not limit the maximuminstantaneous bit rate on the air interface. The value of the parameter iscompared to the user bit rate of the HS-DSCH MAC-d flow, excludingMAC-hs header, RLC header and padding.

Maximum value of this parameter depends on the licensed features. Ifthere is no license for the feature HSDPA 15 Codes, the maximum value is3456 kbps. If HSDPA 15 Codes feature is licensed, the maximum value is6784 kbps.

6.13.3 HSDPA mobility handling

HSDPA mobility handling takes care of the data connection mobility whenHSDPA is active for the connection. HSDPA mobility is a standard featurein I-HSPA. Serving HS-DSCH cell change and SHO of the associatedDPCH is not an optional feature in I-HSPA.

This functionality enables the usage of HSDPA Serving Cell Change andHSDPA Soft/Softer Handover for Associated DPCH. Iur interface isneeded to generate SHO for the associated DPCH.

The HS-DSCH serving cell change feature is controlled with severalplanning parameters. There are feature-specific parameters to setthresholds for the Ec/No and UL SIR error triggering and the required levelin a target cell. In addition to the feature-specific parameters,AdditionWindow and DropWindow parameters in the HSDPA FMCSparameter set are used to control the serving cell change and the SHOarea for the associated UL channels.

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The HS-DSCH serving cell change feature can be triggered by the bestserver Ec/No, UL SIR error, and event 1B/1C. The most commontriggering reason is the periodical Ec/No measurements. TheHSDPAServCellWindow parameter determines the maximum alloweddifference between the best cell Common Pilot Channel (CPICH) Ec/Noand the serving HS-DSCH cell CPICH Ec/No. It is recommended to set theDropWindow parameter higher than the HSDPAServCellWindow, so thatthe serving cell change is normally triggered by the Ec/No measurementsand not by the event 1B.

The AdditionWindow in the HSDPA Intra-Frequency MeasurementControl (FMCS) controls the active set size of the associated UL channels.It does not have direct impact on the serving cell change functionality andtriggering. However, the used High-Speed Dedicated Physical ControlChannel (HS-DPCCH) power offsets for the Channel Quality Indicator(CQI) and HARQ Ack/Nack are higher during the SHO of the associatedchannels.

The measurement control and handover path parameter sets, which arededicated to the UE having HS-DSCH transport channel allocated, areapplied to the intra-, inter-frequency, and inter-RAT measurement types.The HSDPA-specific measurement control and handover path parametersets are determined for the following parameter object classes:

. FMCS (intra-frequency measurement control)

. FMCI (inter-frequency measurement control)

. FMCG (inter-system measurement control)

. HOPS (intra-frequency handover path)

A particular parameter set is associated with the HSDPA UE by thefollowing identifiers: HsdpaFmcsIdentifier, HsdpaFmciIdentifier,HsdpaFmcgIdentifier, HsdpaHopsIdentifier.

Radio Network Planning (RNP) parameters can be adjusted by theoperator.


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6.14 HSUPA features and parameters

I-HSPA uplink provides both UL DPCH and HSUPA services. This sectiondiscusses the HSUPA related parameters and their impact. The purpose ofHSUPA parameter planning is to allow the deployment of the HSUPAfeatures set at the planned performance target. HSUPA features areintroduced in I-HSPA release 1. 3GPP Release 6 UEs support HSUPA,thus the penetration of the mobiles needs to be taken into account whenallocating capacity to HSUPA.

HSUPA can be used to increase both the uplink total cell throughput andthe uplink individual connection throughput. HSUPA increases theefficiency of the uplink Air interface and can be used to relieve congestion.This is only effective if the penetration of HSUPA terminals is relativelyhigh.

HSUPA connection

It is possible to limit the number of HSUPA connections per cell(MaxNumberEDCHCell) and per logical cell group (MaxNumberEDCHLCG).The default values for these parameters represent their maximums. Themaximum number of connections per logical cell group is equivalent to themaximum number of connections per Node B when assuming a singlelogical cell group per Node B.

It is also possible to reserve a subset of the total number of connections forsoft handover (NumberEDCHReservedSHOBranchAdditions). A relativelylow default value for this parameter means that soft handover and non-softhandover connections tend to be served on a first come, first served basis.

The MaxTotalUplinkSymbolRate parameter defines the maximumsymbol rate per HSDPA connection. This parameter has units of kbps. AnE-DPDCH has one bit per symbol so these units are used inter-changeably. The figure of 3840 kbps corresponds to the 2xSF2configuration, whereas the figure of 1920 kbps corresponds to the 2xSF4configuration. HSUPA 2.0 Mbps feature requires the use of the 3840 kbpsconfiguration. Otherwise, the maximum bit rate of 1.44 Mbps can beachieved using the 1920 kbps configuration.

Packet scheduling

The PrxNoise parameter is used in the same way as for a traditionalWCMDA network. It initialises the value of the background noise floorwhen auto-tuning is enabled. Otherwise, it defines the value of thebackground noise floor.

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The PrxMaxTargetBTS parameter defines the maximum increase in uplinkinterference. This target is used by the Node B packet scheduler ratherthan the I-HSPA Adapter packet scheduler. This means the valueassigned to PrxMaxTargetBTS should be greater than the value assignedto PrxTarget. If PrxTarget is left with a relatively high value, there is anincreased probability that I-HSPA Adapter will schedule large quantities ofuplink resource. This is likely to limit the quantity of resource which theNode B can schedule for HSUPA.

The PrxLoadMarginEDCH parameter defines the threshold used todetermine when power based packet scheduling is used rather thanthroughput based packet scheduling. Throughput based packetscheduling is used if the own cell load is less than the uplink loadcorresponding to the interference increase defined by this parameter, andif the throughput based resource margin is greater than the power basedresource margin. Configuring a value of 0 dB disables throughput basedscheduling.

A static target can be based upon the value assigned to PrxTarget.Alternatively, the adapter can generate a dynamic value which variesbetween PrxTargetPSMax and PrxTargetPSMin according to the loadand priority of the HSUPA and NRT DCH connections. In either case,PrxTarget is used as a static target when there are no active HSUPAconnections. The default values for PrxTargetPSMax andPrxTargetPSMin are equal to the default value of PrxTarget. Thisconfiguration results in a static target uplink interference power.

Happy Bit

The HappyBitDelayConditionEDCH parameter configures the UEgeneration of Happy Bit. This parameter corresponds to the delaycondition specified by 3GPP. A UE can indicate that it is not happy if thetotal buffer status would require more than 'delay condition' ms to be sentwith the current serving grant. This means that the delay condition has animpact upon the number of UE reporting that they are unhappy. The NodeB packet scheduler uses this information when prioritising which UE toupgrade. Decreasing the delay condition will increase the number of UEreporting that they are unhappy.

HSUPA mobility

I-HSPA HSUPA supports soft/softer handovers and serving cell changesfor HSUPA users, allowing HSUPA in the whole cell coverage area andbetween the cells. This enables full mobility for the HSUPA users andwidens the coverage area of a given bit rate. The gain is significantespecially with high bit rates.


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The following intra-frequency soft/softer handovers are supported for E-DCH:

. Intra BTS intra I-HSPA Adapter softer handover

. Inter BTS soft handover for signaling radio bearer

The algorithms of HSDPA are followed. The HS-DSCH and E-DCH servingcell is always the same.

The HSPAFmcsidentifier parameter points towards the FMCSparameter set used by HSUPA connections.

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7 Dimensioning Adapter and interface

7.1 Hardware description and performance

I-HSPA adapter is simplified into the shape of one plug-in unit, which canbe deployed as the BTS frame. The simple and flat structure provides theswitch and the transportation with possibly less congestion and delay.

I-HSPA adapter will operate in Flexi BTS environment as a separatemodule. The I-HSPA adapter has been designed to the standard 19-inchrack format and can be installed in a Nokia Flexi BTS casing 2U, the NokiaGSM/EDGE Ultra Site cabinet, or a standard 19-inch rack enclosure.Connectivity to BTS is implemented with Gigabit Ethernet interfaces(1000Base-Tx).

I-HSPA adapter effectively brings the functionality of a packet switchedRNC to the base station, and allows connection of the SGSN and GGSN incase One Tunnel Approach is supported, or only to SGSN if it is notsupported. I-HSPA adapter has the following functionality:

. 3GPP defined protocols to handle terminals compliant to 3GPP. Telecom and Mobility signaling procedures. Header compression as part of PDCP

. I-HSPA specific protocols and procedures. Authentication and authorisation. Adapter to adapter interface and related Inter I-HSPA

handover, PDP context transfer and paging procedures

. Radio Resource Management. Load control. Admission control. Power control. HO control. Packet scheduling

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Dimensioning Adapter and interface

. WCDMA scrambling codes management

. RNTI management

. Subscriber and PDP context management. Allocation and management. Triggering PDP context re-establishment

. CS service enabling Handover. Active CS user are moved to the CS network (2G or 3G)

I-HSPA module consists of two separate modules; Pentium module andDSP module. Same segregation is regarding the logical structure, I-HSPAmodule consists of the Pentium and DSP logical module.

I-HSPA Adapter supports the following Ethernet interfaces:

. 3 x 10/100/1000 BASE Tx Ethernet interfaces

. One optional optical Ethernet interface

The interfaces are used as follows:

. Local Management Port (for maintenance): copper interface.

. BTS interface Iub (internal BTS connection): copper interface.

. Transport interface (connection to outside of BTS): copper or opticalinterface.

Figure 22. I-HSPA network over Ethernet

OMS

Adapter

MSC

GGSN

SGSN

lub

Flexi BTSAdapter

FCM

L2Switch

FTM

OMU

L2Switch

lub Trans

DSP

GE port, to external core network

GE port, to internal lub network

O&M

IuPS-CP

IuPS-UP

IuCS

lur


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FlexiBTS can have an FTM port for communication to the core network viaATM channels. In this case, ATM is used as another L2 network for sameIP traffic to/from user or control plane processors, instead of externalEthernet. Only one of the two options – either Ethernet or ATM – can beused in one adapter to connect to the core network.

Figure 23. I-HSPA network over ATM

Available FlexiBTS Sub-Modules are:

. FTPB: 8 x E1/T1/JT1 symmetrical

. FTEB: 8 x E1 coaxial

. FTIA: 2 x FE (not available for Release 1) + 1 x GE (not available forRelease 1) + 4 x E1/T1/JT1

. FTFA: 2 x Flexbus

. FTOA: 1 x STM-1

7.1.1 Capacity and performance

The requirement of the capacity and performance are shown in the TableCapacity and performance data for I-HSPA adapter. The Table representslimitations of the one I-HSPA adapter.

OMS

Adapter

MSC

GGSN

SGSN

lub

Flexi BTSwith I-HSPA Adapter

FCM

L2Switch

FTM

OMU

L2Switch

lub

DSP

GE port, to external core network

GE port, to internal lub network

O&M

IuPS-CP

IuPS-UP

IuCS

lur

Trans

LGM

ATM

ATM port, to external core network in this case

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Table 16. Capacity and performance data for I-HSPA

Parameter Restriction / Limits

Number of users per cell for HSDPA 48

Number of users per cell for HSUPA(simultaneous users)

19

Number of HO in sec per adapter 100

HSDPA peak rate for one user (10 codeterminal)

10.8 Mbps

HSUPA peak rate for one user 2 Mbps

Throughput capacity in DL per cell 14.4 Mbps

Throughput capacity in UL per cell 2 Mbps

Throughput capacity per I-HSPA Adapter Depends on the capacitylicense

I-HSPA Adapter connectivity:

Number of SGSN connections 16

Number of Cells per I-HSPA adapter 3

Number of Iur interfaces per I-HSPA adapter 32

HSDPA users per I-HSPA Adapter 144 (48 x 3)

Number of UTRAN Registration Areas 7

BTS connectivity:

Number of Cells per BTS 3

Number of HSDPA users per BTS 144 (48 x 3)

Number of HSUPA users per BTS 24

Network user plane capacity:

HSDPA throughput towards IuPS (per I-HSPA) 14.4 x 3 / overhead conversionfactor

HSUPA throughput towards IuPS (per I-HSPA) 2 x 3 / overhead conversionfactor

Overhead conversion factor (depends on theaverage packet size and protocol stack):

GTP/UDP/IP/Eth

GTP/UDP/IP/AAL5/ATM

100 bytes 1.9 1.7

300 bytes 1.3 1.3

500 bytes 1.2 1.2

IuPS capacity:


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Table 16. Capacity and performance data for I-HSPA (cont.)

Parameter Restriction / Limits

Number of active GTP tunnels per I-HSPAadapter

294

Number of inactive and active GTP tunnels perI-HSPA adapter

5000

Additional information regarding I-HSPA adapter are:

. I-HSPA adapter supports up to 1+1+1 BTS configuration (one cell,one sector, one carrier frequency).

. Capacity and performance target must be achieved with IPSecenabled.

7.1.2 Capacity of the I-HSPA Adapter

There are several capacity license steps for the I-HSPA adapters.

Table 17. Release 1 license

Capacity licensesteps, Release 1

Throughput




Capacity is based on the daily BH network traffic and therefore is notlimiting the system capabilities such as the peak data rates. Similarlythroughput limitation is based on software and I-HSPA adapter hardwarehas higher capacity. No hardware change is required when license isupgraded.

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7.2 Traffic model

Before making successful dimensioning for I-HSPA architectureappropriate traffic model must be defined. In this section the definition for I-HSPA traffic demand is explained in general. This section also describesthe basic concept for traffic modelling. Modelling should be done insufficient details for a dimensioning and further for a capacity planning.

The traffic model can be split to two parts:

. Subscriber model.

Based on this model all control plane and user plane events can becomputed (control plane traffic is not described in detail but it isassumed that control plane traffic is 10% of user plane traffic).

. Application model.

This can be used to estimate user plane traffic based on envisionedapplication usage.

7.2.1 Subscriber traffic model

Using the traffic parameters the traffic models are set up which define thebehaviour of an averaged subscriber. The description of subscriber trafficrelies on traffic models in the busy hour. Exceptional traffic patterns (NewYear traffic peak) are not considered for dimensioning.

Table 18. Subscriber traffic model

Parameter Unit Description

Number of subscribers (S) - Total number of I-HSPA subscribers

Attached % Number of attached subscribers (% oftotal subs)

Number of subscribers (Ss) - Number of subscribers on Iur interfaceusing the I-HSPA adapter as source

Number of subscribers (Sd) - Number of subscribers on Iur interfaceusing the I-HSPA adapter as drift

Number of subscribers (Sr+i) - Number of roaming and interceptedsubscribers (not usind OTA)

Number of subscribers (So) - Number of subscribers on Gn interface

Data packet size average Byte Average size for an packet

Data packet size UL Byte Average size for an UL packet


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Table 18. Subscriber traffic model (cont.)


Data packet size DL Byte Average size for an DL packet

Data Packet Rate (UL+DL) ppBH Total data packet rate (UL+DL)

Data packet rate ratio UL/DL - Ratio between UL and DL data packetrate

Real time traffic % Percentage of real time traffic

Data throughput bit/s Data throughput per subscriber

Real time traffic % Percentage of real time traffic

Average subscriber generates both control plane and user plane traffic.User plane traffic estimation can be done via measurements (if themeasurements exist) or can be calculated if detail application traffic modelexist. Additional control plane traffic that can be also generated bysubscribers (for example, PDP context activation, handover) are onlyestimated for release 1. Control plane traffic is estimated with 10% of userplane traffic.

7.2.2 Application model

Application model should provide information about usage of theapplications by average subscriber or it can only give average throughputfor average subscriber for application aggregate as it is done in TableApplication traffic model for nRT traffic.

Table 19. Application traffic model


Real time application

Calls per busy hour 1/BH Number of activations of an applicationper busy hour per powered UE

Call duration s Average usage duration of an application

Bandwidth per call bit/s Average bandwidth per call taking allused codec’s of an application intoaccount

UL/DL ratio bandwidth per call - Ratio between uplink and downlinkbandwidth per call of an application

Packet size UL Byte Average size for an UL packet

Packet size DL Byte Average size for an DL packet

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Table 19. Application traffic model (cont.)


Non real time application

Average throughput bit/s Average throughput per powered on UE

UL/DL ratio throughput - Ratio between UL and DL throughput

Packet size UL Byte Average size for an UL packet

Packet size DL Byte Average size for an DL packet

7.3 Feature description

7.3.1 QoS

Feature description

I-HSPA Adapter support QoS, for some traffic it is expected to have higherpriority (for example, VoIP and CP). Because it deploys IP basedprotocols, it is allowed to set different DSCPs values for the different traffictypes (for example, control plane, user plane, and Operation andMaintenance). DSCP marking is based on RAB 3GPP QoS parameters.The minimum requirement is to support two different priority classes: VoIP(and other higher priority) and other traffic.

For the user plane traffic prioritisation of RABs with Conversational,Interactive, and Background traffic classes, that are mapped to HSPA,transport channel is based on the following RAB parameters received fromthe core network:

. Traffic Class (TC)

. Traffic handling priority (THP)

. Allocation Retention priority (ARP)

Parameters mentioned above are mapped according to an operatordefined mapping rules to prioritisation value that is used inside Adapter (toprioritise connection). To the uplink direction I-HSPA Adapter marksoutgoing traffic based on the above rules.


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For the control plane and Operation and Maintenance traffic, the DSCPvalues must be possible to set, otherwise the user plane traffic can blockthem.

I-HSPA support pre-emption. Pre-emption is based on RANAP ARPpriority level value. I-HSPA Adapter makes pre-emption when there iscongestion in the I-HSPA RAN and no new users can be allowed withoutaffecting existing users’ QoS or status. With pre-emption, I-HSPA Adaptermakes room for higher pre-emption value connections. Each connection isunder pre-emption and each higher priority connection can pre-empt lowerpriority connection.

QoS mechanism

I-HSPA Adapter supports QoS by setting DiffServ code points (DSCP) fortraffic differentiation:

. IP level QoS (DiffServ) supported between User, Control andManagement plane and inside the User plane (mapping based onRAB).

. In case of TDM backhaul, five ATM VCC‘s (five QoS flows) can beconfigured:. U-plane (IuPS-u, Iur-u). C-plane (IuPS-c, Iur-c). M-plane

. Ethernet level QoS (802.1p) is Release.2 feature candidate (SWupgrade).

Application does the traffic class mapping and sets the DSCP. FigureOverview of QoS traffic differentiation shows QoS overview.

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Figure 24. Overview of QoS traffic differentiation

The possible bottleneck in the I-HSPA Adapter system is the process loadof L2 switch (CPU and DSP), where the traffic management is mainlydone. On this L2 level, 4 traffic classes are supported and the schedulemechanism is weighted fair queue. In most cases, the DSCPs are used forscheduling.

The external network elements should also support DSCPs, such as OMS,SGSN, GGSN, routers, and switches.

As the switch bandwidth is large enough for the possible traffic, the RTandnRT message are in the same traffic class. There is a total of 1 Mb framebuffer memory in the switch. All the ports and queues share this memory. Ifthere are no queue buffers in the ingress packets, the packets aredropped. IP QoS is mainly done in the L2 switch.

NetAct / OMS

IP

I-HSPANode B

SGSN

GGSN

UDP

(User) IP

U-plane C-plane M-plane

RANAPRNSAP

SCTP TCP

BTSOM

IP

L2

L1

QoSmarking(DSCP)

L2 L2

L1 L1

GTP-U

IP

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UDP

GTP-U

IP

Eth MAC

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QoS impact on planning

Quality of Service within a network, respectively a node in a network, isrequired to ensure a treatment for traffic of a specific application accordingto its requirement.

In a first step this is done in mapping specific application requirements tothe UMTS Bearer Service. This includes the mapping of applications to theUMTS QoS Traffic Classes: Conversational, Streaming, Interactive, orBackground, which characterise the UMTS Bearer Service. The mobilestation is responsible at PDP Context Activation/Modification for themapping of the application requirements to the UMTS Bearer Serviceattributes.

The differentiation between traffic at the IP layer is done via DSCPs. Thefollowing general dimensioning rules apply:

. Conversational and streaming UMTS traffic class must bedimensioned as the stream traffic.

. Signalling traffic must not be affected by overload situations in any ofthe UMTS traffic classes.

. Interactive traffic: the dimensioning method depends on the actualDIffServ mapping at the egress.

. Best effort traffic: there is no performance guarantee for this traffic.Mapping of any traffic to the best effort should be avoided. In casethere is substantial amount of interactive traffic, an aggressivedimensioning approach is to simply reserve as much bandwidth asexpected offered load. However, since additional delay should notbe introduced, the suggestion is to dimension best effort traffic as anextra elastic traffic aggregates.

For dimensioning purpose, bandwidth computed for the stream and elastictraffic should be added.

7.3.2 Mobility

One of the important features which should be supported in the I-HSPAnetwork is mobility, or the handover. First, an overview of the mobilitymanagement is described together with a general explanation of thehandover types that can occur in the network.

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Before the handover happens, UE and the network exchange a set ofsignalling messages to distinguish if the handover is necessary, and if yes- which type will occur. The UE and the network (iNB in case of I-HSPAarchitecture which consist of a NodeB and I-HSPA adapter) determine thequality and strength of a radio transmission. The UE also determines thesignal strength and quality of its own as well as the local iNBs. Themeasurement values are compiled in a measurement report for use by theiNB as a basis for deciding for or against the handover. If a handover isdecided upon, the new iNB is activated and included in the so-called activeset. The iNB is responsible for the decisions regarding the acceptance orrejection of handovers, while the execution (initiation of contact with thenew iNB) is the responsibility of the UE.

Generally, there are three types of handover: softer handover, softhandover and hard handover. Softer handover is a handover between thesector cells in the same iNB. The transmitted information received throughantennas of the different sector cells is handled within one iNB. Softerhandover is internal iNB affairs. See Figure Softer handover.

Figure 25. Softer handover

Soft handover refers to a handover in which a UE transmits its userinformation through more than one iNB at the same time. This type ofhandover prevents an increase of the UE power in boundary areasbetween different cells, which reduces the interference level and,therefore, increase the system capacity. The UE communicates with morethan one iNB, which means that more than one cell is involved insignalling. The identity of the cells involved in the connection is stored asan active set. The iNBs involved in the handover procedure exchangesignalling information and user information through the Iur interface.

UE

Cell 1

Cell 2 iNB


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Figure 26. Soft handover

Hard handover refers to a handover in which the UE transmits its userinformation only through one iNB at any time. Before the handover, UEcommunicates with old iNB over a specific physical channel. After thehandover procedure, UE changes physical channel and thencommunicates with the new iNB. This type of a handover also happensduring an inter-system handover when the UE moves from one type of thearchitecture to a different one (for example, from I-HSPA architecture tothe 2G/3G network).

Figure 27. Hard handover

UEIur

iNB

iNB

UEor

UE

BTS RNC

3G BSS or 3G RAN

iNBiNB

iNB

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During the handover, UE communicates with more than one iNB (exceptsofter handover within one iNB). Before the handover takes place, the UEis connected to the serving iNB which is responsible for control of thehandover. The other iNB involved in handover, called drift iNB, isresponsible only for allocating radio resources. If the handover happens,drift iNB will adopt the functions of the serving iNB with an SRNSrelocation procedure, and the previous serving iNB will be released. DriftiNB becomes a new serving iNB and all traffic goes through the new iNB.

The SRNS relocation procedure differs for the soft and hard handovers. IfSRNS happens during soft handover, all signalling goes through Iurinterface, therefore the UE is not involved in the procedure, suchprocedure is UE-not -involved type. But if SRNS happens during hardhandover or Iur is not present in the network, UE must be involved in theprocess, and such SRNS procedure is UE-involved type.

Figure 28. Handover explanation

Feature description

I-HSPA architecture is a fully mobile solution which supports all types ofhandover mentioned in Mobility. These types are:

UE UE

before handover after handover

SRNS relocation

drift iNB

serving iNB old iNB

new serving iNB


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. Intra-system handover within I-HSPA.

. Inter-system handover between the I-HSPA and traditional 3GPP(WCDMA/HSDPA):. CS service enabling handover. PS handover, hard handover without Iur

. Inter-system handover from I-HSPA to 2G/WLAN or to any IP basedaccess.

For voice purposes, I-HSPA Release.1 architecture supports VoIP service.The intra-system handover between iNBs is fast enough to support VoIPservice. The goal for the inter-system handover between I-HSPA andtraditional 3GPP is to be the same as normal RNC relocation in 3GPP.Inter-system handover from I-HSPA to other IP based accesses, such asWLAN, happens on the IP level.

1. Intra-system handover within I-HSPA.

In this case it is possible to distinguish different cases of handover,since each of them is possible within I-HSPA:

a. I-HSPA Intra system mobility based on hard handover (no Iurinterface): this type of a handover enables basic mobilitybetween iNBs without Iur interfaces. It enables direct mobilityfrom the HS-DSCH in one cell to the HS-DSCH in another cell.Between the iNBs a standard hard handover procedure isused. This case also exists when the Iur interface is present inthe network but disabled by the operator.

b. A handover within iNB, called softer handover: since each iNBis configured with three radio frequencies, which means threecells, handover can happen between two cells on the sameiNB, where possible multiple cells in the active set are handledby the iNB itself. Pure intra-iNB case is considered simplewhile all the signalling is inside one iNB.

c. Soft handover, where Inter-iNB handover happens: this type ofa handover may exist only if Iur interface is present and notdisabled in the network. It is important to mention that this typeof a handover is possible only for release 5 UE and only in UL.DL in release 5 UE and both UL and DL for release 6 UE, arehandled by HSDPA and HSUPA technologies which are notsupported over Iur interface. In these cases only hardhandover between two iNBs can happen. Figure Rel.5 UEhandover shows the behaviour during the handover in case ofDL and UL.

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Figure 29. Rel.5 UE handover

Figure depicts the following:. Hard handover happens for DL and new DL channel (HS-

DSCH) connects UE with new serving iNB, old DL channel isreleased.

. Soft handover happens for UL and new UL channel (DCH) isestablished, but old channel also exist, so there are two activeUL DCH channels.

Rel.5UE

before handover

CN

Uu (rel.5

)

Uu (rel.5)

Iu PS

Iur

Rel.5UE

CN

Uu (rel.5

)

Uu (rel.5) Iu PS

Iur

after handover

HS-DSCH data flow

signaling DCH andUL DCH data flow

Iu PS data flow

serving iNB

drift iNB

drift iNB

serving iNB


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. All UL traffic (signalling and data flow) goes through Iurinterface.

. SRNS relocation occurs which does not release old ULchannel connection, but it releases DL channel (this solutionkeeps UE in UL synchronisation on those radio links tofacilitate fast backward relocation if it will be required).

2. Inter-system handover between the I-HSPA and traditional 3GPP(WCDMA/HSDPA):

I-HSPA uses standard interfaces towards the existing RNCs throughthe core network. The radio network will see the handover as astandard combined hard handover and a serving RNS relocation. I-HSPA uses Iu interface in the Inter-system handover. I-HSPA andtraditional 3GPP can use same GGSN and IP addresses so that thePDP context can remain the same.

This type of handover also involves CS calls. The preferred solutionfor CS calls is that an iNB has IuCS signalling link to the MSC server,so that the CS network can make paging and then reconnect UE tothe CS network using hard handover and SRNS relocation.

However, it is possible that not all the operators or sites have IuCSlink (or IuCS link is not working to MSC). This means that using Iurelocation is not always possible. There is a need for backup solutionwhich can be used for UE redirection. This case is solved withfeature CS service enabling handover. This solution can also beused in case of IuCS link error.

3. Inter-system handover from I-HSPA to 2G/WLAN or to any IP basedaccess:

This type of a handover is similar to the previous one, for except inthis case the UE is forced to initiate the new cell re-selection andexecute the Routing Area Update (RAU) procedure to the targetSGSN, if access to a new cell generates RAU. Also the CS serviceenabling handover feature can be present if necessary.

Mobility mechanism

User in movement can trigger the mobility mechanism, which means that ittriggers one type of handover (soft, softer, or hard). Each type of handoveris followed by certain signalling traffic. After successful the handoverprocedure takes place, the user remains connected to either the I-HSPAsystem through the same iNB, or the new one, or the user is connected tothe different system (2G/3G or any other IP based access).

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I-HSPA Release 1 supports only the PS services. For the voice service,VoIP is used. Regarding the CS services, iNB will have only IuCSsignalling connection to an MSC to ensure that paging can be supported.In case of unavailability of the IuCS connection, the feature CS ServiceEnabling Handover should be used to provide seamless CS handover.

Mobility impact on planning

Mobility function plays important role during user movement. With that inmind, I-HSPA architecture has covered different handover types in order toprevent undisturbed movement of each user. Different handover scenarioshave different impact on planning.

For the softer handover, when the user changes only cells of the one iNB,there are no impacts to the iNB-interface planning since all signalling anduser traffic remains in the same iNB.

Hard handover has no impact on the interface dimensioning. During thehard handover, the UE leaves the observed iNB. With the assumption thata certain percentage of the users is leaving the iNB, it can be alsoassumed that the same percentage of the users is entering the iNB.Therefore the total amount of the users remains the same and the amountof signalling and data traffic remains the same.

Soft handover must be kept in mind during an interface dimensioningbecause it has impact on dimensioning. Soft handover involves Iurinterface between two iNBs. Since traffic through Iur interface exists, it isnecessary to involve all signalling and user Iur traffic during thedimensioning .

7.3.3 One Tunnel Approach

One Tunnel Approach (OTA) functionality enables direct user plane tunnelbetween RAN and GGSN within PS domain.


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Figure 30. One Tunnel concept

This approach is based on assumption that user plane traffic will bypassSGSN except in the following cases:

. In roaming case;

. For the subscriber that has Lawful Interception in the SGSN;

. For the subscriber that has controlling Camel services active;

. GGSN does not support one tunnel approach.

The SGSN handles the control plane signalling and makes the decisionwhen to establish direct tunnel or use two tunnels. The SGSN performscontrol function while the GGSN is responsible for all user plane transportfunctionality.

The main principle of this solution is that whenever RABs are assigned forPDP context (or re-assigned) the SGSN decide whether to enable directuser plane tunnel or if it needs to handle user plane data and use twotunnel.

I-HSPA

SGSN

GGSNIu

Twotunnel

Twotunnel

Onetunnel

GTP User Plane

GTP Control Plane

RANAP signalling

Gi

Gn

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The One Tunnel Approach separates transport and control functionality ofthe SGSN in applicable scenarios. The result of this separation are anSGSN controller (cSGSN) performing all control functions of an SGSN andan enhanced GGSN (xGGSN) which performs SGSN and GGSN transportfunctionality. This enables a direct GTP tunnel between the Radio AccessNetwork and the xGGSN. The One Tunnel Approach gains an improvedefficiency by bypassing the SGSN.

I-HSPA supports OTA but it also support standard access to a corenetwork (the One Tunnel Approach has no impact on the RAN).

OTA impact on planning

Two possibilities exist and can be seen in figures I-HSPA networkarchitecture with OTA and I-HSPA network architecture without OTA (twotunnels).

Figure 31. I-HSPA network architecture with OTA

Iur SGSN

Gn-UP

NSN based network

Iu-PS-CP GGSN

IP network

Internet

Enterprises

Standard Uu air IF(Rel5/6)

Gn-CP

I-HSPANode B

I-HSPANode B


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Figure 32. I-HSPA network architecture without OTA (two tunnels)

During the planning it is important to know how the traffic is distributedbetween the interfaces, for example, how much user plane traffic isforwarded to SGSN (IuPS-UP, two tunnels) and how much traffic isforwarded to GGSN (Gn-UP, OTA).

7.4 Traffic modelling

The requirements for dimensioning traffic for packet switched networkscan be given at different aggregation levels:

. per application, based on the application characteristics andrequirements, or

. per aggregates, based on the traffic classes characteristic andrequirements (each application is mapped to a traffic classdepending on a QoS concept).

Iur

Third party core network

Iu-PS

GGSN

IP network

Internet

Enterprises

Standard Uu air IF(Rel5/6)

Gn

SGSN

I-HSPANode B

I-HSPANode B

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Basic requirements are traffic volume (for example, traffic in bits/secondper user in the busy hour) and certain statistical characteristics (forexample, bursts, peak bit rates per flow/aggregate, and so on). In addition,there is a need to specify QoS requirements for each application/aggregate.

For dimensioning purposes it is not reasonable to model all applications indetail, as it would make dimensioning process too complex. A feasiblesolution is to dimension all applications in the framework of two broadtraffic aggregates: elastic traffic (nRT) and stream traffic (RT). Eachaggregate has similar QoS requirements. There are several techniques tosupport QoS in an IP network. The techniques differ regarding theimplemented traffic control mechanisms to realize a required QoS. Trafficcontrol influences the handling and forwarding of packets, for example bymeans of prioritisation.

. Over provisioning: traffic control is not implemented. However, QoSrequirements can be fulfilled by providing a sufficient amount ofspare bandwidth, as long as the total load is bounded. Additionally itcan be required that the traffic mix on a link fulfils certain criteria.

. DiffServ: UMTS traffic classes are mapped at the DiffServ edge toone or more DSCP. Traffic is also shaped at the DiffServ edge. Theimplemented PHB within the DiffServ domain must guarantee therequested QoS.

Figure Example mapping of applications to IP transport aggregatedescribes the mapping approach. In the Figure, the arrows on the left sidemap applications to the UMTS traffic classes. The arrows on the right sidespecify the transport aggregation of traffic classes to QoS aware IPtransport aggregates. An arrow in the mapping from the applications toUMTS traffic class designates that the respective application generatestraffic in the corresponding UMTS traffic class (according to the subscribertraffic model of the operator).


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Figure 33. Example mapping of applications to IP transport aggregate

The relevant characteristic for an application mapped to elastic traffic is thetransport of an object (for example, a file, a request, or a transaction).Therefore, the primary QoS target is related to the transfer time of such anobject. Applications described by this model are E-mail, WWW as well asWAP and SMS. The word elastic reflects the fact that TCP/IP, which issensitive to network conditions and adapts the sending rate of data duringan object transfer, transports the major amount of the traffic in this class.

Applications described as stream traffic do not transport single objects.Instead, a stream of packets is transferred with stringent requirements fortransfer delay and delay variation (jitter) per packet during a session.Typical applications described by this model are VoIP, video conferencing,and video streaming.

QoS requirements for streaming traffic must guarantee absolute delay andbandwidth requirements. Elastic traffic aggregates can guarantee onlyrelative priorities.

Applications

Stream trafficStream traffic

Stream traffic

Elastic traffic

Elastic traffic

Elastic traffic

DiffServ Link

.

.

.

Voice

Video

WWW

Email

Conversational

Streaming

Interactive

Interactive

Interactive

Background

EF

AF11

AF21

AF31

1

2

3

View of Planner:List of Applications

View of UMTS Network:Traffic Class

View of IP Network:Transport Aggregate(Example DiffServ)

Description bynetwork planner

Description byUMTS network

Description byIP network

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Figure Logical link model shows a model of the traffic flows that can bepresent in a link. Depending on the deployed QoS mechanisms,dimensioning has to consider the following effects:

. Traffic in one class can affect traffic in any other class. For instance,in case of over provisioning the bandwidth required to transportstream and elastic traffic can not be added independently.Reservation of an additional spare capacity is needed to take care ofthe effects that the elastic traffic has to stream traffic and vice versa.

. Overload in one class can affect any of the other classes present inthe link.

. One class can use bandwidth shares of others whenever they arenot fully utilised. Taking into account such multiplexing gains leads toa better utilisation of the link.

Figure 34. Logical link model

Clearly, a general approach, taking into account all possibleconfigurations, interactions, and multiplexing gains, is too complex for thenetwork planning purposes. To simplify dimensioning the followingassumptions are made:

. Any multiplexing gains between the classes are not taken intoaccount.

. Overload situations are taken care of before dimensioning the link;for instance, by CAC mechanisms, traffic shapers, or propercomputation of the worst-case offered load, and so on.

Conversational / Streaming

Interactive - priority 1



Background

stream

elastic

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Even with these strict assumptions, link dimensioning heavily depends onthe IP transport aggregation in use.

7.4.1 Dimensioning the Adapter

The performance and capacity of an I-HSPA adapter can be restricted bystatic or dynamic limits. It is necessary to verify that the requirements foran I-HSPA adapter are in line with the restrictions defined on the I-HSPAadapter. Because of that, some calculations have to be done for requiredtraffic model and required configuration. The required traffic model has tobe available and it can be provided either as measured values or by theoperator. Traffic model parameters are discussed in Traffic model andDimensioning.

The traffic model is used to define an average subscriber profile, thenetwork model, the mobility parameters, and some general parameter persubscriber. These inputs (from the traffic model) are required in calculatingthe load caused by the traffic (defined in the traffic model). The trafficmodel parameters and the calculated capacity needed for an adapter, canbe compared with defined performance and limitations on an I-HSPAadapter.

7.4.2 Dimensioning the Interface

ASN interface dimensioning addresses the problem of how to calculate thecapacity required on the transport links taking into account the offered usertraffic, QoS requirements, and the transport overhead. Specification of thetransport capacity requirements is of the utmost importance if the operatordoes not have its own transport infrastructure and has to use leased lines.

All the interfaces are IP/Ethernet based but in case ATM connection isneeded, the FTM module of FlexiBTS is connected as the interworking unitof ATM and IP. For the I-HSPA platform, the connection through FTM toATM network requires specific transport protocols. It has directconnections to SGSN and GGSN, internal Iub interface to the NodeB, andIur connections to other I-HSPA adapters.

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Figure 35. Overview of I-HSPA interfaces

Each of the above mentioned interfaces are used for control and userplane traffic. To be able to dimension interface and/or links, it is necessaryto separate dimensioning of the user plane traffic and dimensioning of thecontrol plane traffic. User plane traffic modeling and interfacedimensioning is described in the document, however the control planetraffic dimensioning is approximated.

SGSN/AAA

WBTS withiHSPA adapter

RANAP

SCCP

M3UA

SCTP

IP

Layer 2/Layer 1

iHSPA

(Iub interface isinternal)

IuPS

Iur

RANAP

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IP

Layer 2/Layer 1

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GTP-U

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8 Planning Adapter and interface

8.1 I-HSPA Adapter and interface planning

An algorithm has been set up that provides step by step instructions onhow to dimension an adapter and the interfaces.

HSPA Adapter and interfaces planning will be discussed together. Thereason for that is that in both cases the throughput is the main planningparameter. Throughput load, or the offered traffic, is calculated from thetraffic model valid for I-HSPA users. The traffic model is in detail describedand specified in Traffic model. Naturally, in addition to throughput there areother parameters relevant for planning I-HSPA adapter and appropriateinterfaces. The planning mainly covers the user plane traffic; control planetraffic is not cover in detail for release 1. Only approximation for controlplane traffic is done, that is, an approximation of generated (throughput)control plane traffic.

As it is described further in more detail, I-HSPA adapter has much lessthroughput capacity (capacity licenses) than can be sent and receivedthrough the GE port which will be allocated for the traffic towards the CoreNetwork (second GE port is connected to an I-HSPA NodeB and the thirdimplements connection towards the management network).

In case of ATM, the available throughput on the interface towards corenetwork can be provided through different sub-modules as listed in sectionHardware description and performance.

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Planning Adapter and interface

8.2 Planning steps

In order to ensure consistency throughout the planning process, thechapter presents step-by-step planning instructions that will guide youthrough the planning process. In addition to that, the check points betweenthe planning steps can be defined to help verify the correctness of theapproach. The following steps should be performed in the presented order.

For general information and features description, see DimensioningAdapter and interface.

Each step involves:

. Gathering information and carrying out the required planningdecisions

. Performing crosschecks

. Computing results and make the decision

Figure 36. I-HSPA adapter and appropriate interfaces planning responsibility

Iur

SGSN

Gn-UPGGSN

IP network

Internet

Enterprises

Gn-CP

Gn-UP

Iu-PS-CP

Iu-PS-CP

Access part planningresponsibility

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I-HSPA


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In Figure I-HSPA adapter and appropriate interfaces planningresponsibility. The red circle indicates for which part of the network theplanning is performed (I-HSPA adapter and the appropriate interfaces).Figure I-HSPA adapter and appropriate interfaces planning responsibilityshows a network with One Tunnel Approach, however a similar figure isvalid for the two tunnels. For more information about One TunnelApproach, see One tunnel approach.

The dimensioning algorithm includes the following steps:

1. Basic planning information

2. Traffic modelling

3. Additional traffic

4. Dimensioning

8.2.1 Basic planning information

Initial planning input:

. Available applications/services.

. Application traffic model subscriber traffic model.

. Performances, capacities, limitations of network element.

. Distribution of the subscribers between One Tunnel and Two Tunnelapproach.

. Subscribers using Iur interface (mobility feature).

As a first step, the basic information has to be collected. Because thecontrol plane traffic is not described in detail in the current document, themain concern is the generated user plane traffic. Therefore, first of all, it isnecessary to clarify which application/service should be available to theuser. The planning can also be based on the aggregation data (set ofapplications/services behaviour in the same way with similar QoSrequirements).

The traffic model has to be known for all applications/services (or theaggregates). The traffic model together with the modelled subscriberbehaviour is used for the calculation of the offered (user generated) traffic,for example, throughput/packet forwarding.

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The planning is done for an I-HSPA adapter, and therefore informationabout the capacity, limitations, and performance for a certain networkelement should be known. Restrictions of any kind have to be specifiedprior to the planning process. For more information, see Capacity andperformance. It must be clear that the I-HSPA adapter is considered fullyloaded only after the first limitation or performance is reached.

Because of the interface dimensioning it is necessary to know whether thesubscriber uses One Tunnel Approach or not. One Tunnel Approach is notused in case of roaming and interception. That means that the roamingand intercepted subscribers do not have a direct tunnel towards GGSN. Inthat case, all the user plane traffic is forwarded towards SGSN through anIu-PS interfaces, while all other user plane traffic is forwarded directly toGGSN.

The Iur interface properties have to be configured. Usually Iur interface isnot used for the high loads, that is, for the user plane traffic. However, incase of mobility it can also be used in those cases. For detailed descriptionof mobility, see Mobility under Feature description. Because of theinterface (in this case, Iur interface) dimensioning, it is necessary to knowhow many subscribers use Iur interface. Note that Iur interface is used forthe user plane traffic in the uplink direction only by the subscribers withRel.5 user equipment.

Crosscheck:

At this point, all the required information has to be at hand.

8.2.2 Traffic modelling

Additional planning input:

. Definition of mapping applications to the traffic classes/aggregates.

. Traffic (volume per application/characteristic) distribution.

. QoS concept and requirements (for the aggregates).

. Mobility.

. Physical interface/node configuration.

. Licencing concept.

It is known which application/service is available for the subscriber fromthe previous step. As discussed in Dimensioning Adapter and interface,the capacity calculation is performed per aggregates. One aggregatedescribes an applications with similar QoS requirements (can also be


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described as Traffic classes). Therefore it must be clear which applicationscan be aggregated together. Basic differentiation should be drawnbetween high priority traffic and other traffic (for example, RT and nRT).The differentiation can also be done for the nRT traffic between the userswith different priority (for example, between web browsing and e-mail).

Table 20. Overview of different possible traffic aggregates/classes

Traffic Class & TrafficHandling priority & anyAllocation Retention Priority

Aggregates example Application

Conversational Aggregate 1 Streaming traffic High priority

Interactive / Traffic handling priority 1 Aggregate 2 Elastic traffic Other traffic withdifferent QoSrequirementsInteractive / Traffic handling priority 2 Aggregate 3

Interactive / Traffic handling priority 3 Aggregate 4

Best effort Aggregate 5

Traffic model and subscriber model for the applications/services should bealready available from the previous step. It has to be clarified what kind oftraffic distribution is expected on the I-HSPA adapter and the interfaces. Allthe traffic generated by the users has to be handled by I-HSPA adapterand distributed towards the Iur, Iu-PS (roaming and intercepted traffic), andGn interfaces. Assuming that the generated traffic is proportional to thenumber of subscribers, the traffic can be distributed between the interfacesin the same way the subscribers are distributed between interfaces.

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Figure 37. Overview of UL/DL traffic/subscriber distribution between interfaces

Iur

Iur

Iur

Iur

Iu-PS

Gn

Gn

Iu-PS

I-HSPA adapter

I-HSPA adapter

Iub

Iub

Subscribers (Ss)using this I-HSPAas serving I-HSPA(only for Rel.5 UE)

Roaming andinterceptedSubscribers (Sr+i)

Subscribers(=S+Ss-Sd-Sr+i)

Subscribers in the

I-HSPA area (S)

Roaming andinterceptedSubscribers (Sr+i)

Subscribers in the

I-HSPA area (S)

Subscribers (Sd)using this I-HSPA

as drift I-HSPA(only for Rel.5 UE)

User plane trafficRel.5/6 UE - DL

User plane trafficRel.5/6 UE - UL

Subscribers (Ss)using this I-HSPAas serving I-HSPAIur interface is not used

Subscribers (Sd)using this I-HSPA

as drift I-HSPAIur interface is not used

Subscribers(=S-Sr+i)


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Figure Overview of UL/DL traffic/subscriber distribution between interfacesshows different traffic handling in UL and DL direction. In DL direction nosoft HO is supported for user plane traffic and Iur interface is not used,while in UL direction it is used since DCH support Soft HO. For detailedmobility description, see Mobility under Feature description.

As the I-HSPA adapter has no redundancy in both hardware and software,its availability depends on the high quality of hardware and softwarethemselves. The redundancy has no impact on the planning and is notdiscussed in this document.

There is only one configuration for an I-HSPA adapter which can differ onlyin the interface types - Ethernet or ATM.

Crosscheck:

Using the total traffic figures, the following limit and configurations have tobe considered:

. Node configuration/licensing: the selection of a certain node-typedepends on node limits.

. QoS configuration: UMTS Traffic classes are mapped to IP transportaggregates at each interface. For instance, each Gn-interface isconfigured to use the same DSCP configuration.

After these three planning decisions it is possible to compute how the totaltraffic is distributed to each node interface and how traffic is aggregatedwith respect to the QoS. The dimensioning targets for such aggregatescan be fixed.

8.2.3 Additional traffic

8.2.3.1 Overhead


. UL and DL average packet size

The dimensioning methods are independent of the actual packetsize. However, the packet size is relevant to dimensioning for thefollowing reasons:

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. Certain node limits are directly related to the packet size. Modernswitches and routers can forward packets at wire speed regardlessof the packet size distribution. However, this is not true for thenetwork devices that work above the IP layer. The performance ofsuch devices strongly depends on the packet size. The number ofpackets per second that can be processed is limited. Therefore,smaller packets require more node resources for fixed averagebandwidth. These decrease the overall node performance.

. The protocol overhead factor depends on the payload size.

Payload traffic and additional traffic is transported using variousnetwork protocols. These protocols cause additional overhead thatmust be considered when dimensioning interfaces. In order tocalculate the overhead, it is recommend to distinguish between thetwo types of overhead:. Logical interface overhead: this overhead depends on the

traffic type, for example, GTP/UDP/IP encapsulation forpayload traffic at the Gn-interface.

. Physical interface overhead: this overhead is caused by theutilised transport technology, for example, Ethernetencapsulation at the Gn-interface.

. Each logical or physical interface overhead consists of severalspecific protocol overheads.

The overhead factor is defined as the quotient of traffic with protocoloverhead divided by the traffic without protocol overhead. It can beassumed that the overhead factor for a single packet of size can beexpressed in the following form:

. Equation 1

Where oh is the size of the additional protocol header.

Under this assumption the overhead factor for a stream of packetsdepends only on the average packet size and not on the packet sizedistribution. The overhead factor for any packet stream can be computedby setting the average packet size in Equation 1.

The average packet size of a stream of packets representing a mix ofapplications can be computed by the following steps:

1. For each application i determine the average packet size psi.

2. For each application i determine bwi, the bandwidth used.


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3. Let bw = ∑bwi be the total bandwidth.

4. The average packet size ps is given by the following formula.

. Equation 2

Crosscheck:

UL and DL (average) packet sizes have to be available. Bases on thesevalues, overhead can be calculated.

8.2.3.2 Control plane traffic


. The percentage that will approximate control plane traffic.

Management and signalling traffic can put additional load in to the system.Therefore, the control traffic is approximated with the values of 10% of theuser plane traffic. For Rel.1 no control plane traffic modelling is done. Thisadditional traffic can be added to the links and interfaces that are reservedfor control traffic.

Crosscheck:

Control plane traffic is always present in the network and must not beforgotten.

8.2.4 Dimensioning

After the setup of the aggregates (done in the second step) it is possible tocalculate the capacity which is needed to provide adequate QoS for thesubscribers. In addition to that, it must not delay the control andmanagement traffic.

As previously mentioned (IP link model 6.4), it can be assumed that eachaggregate needs adequate capacity/bandwidth share. This share must becalculated for each aggregate and it must be clear that additionalpercentage should be added in order to approximate control plane traffic(for Rel.1 no detail control plane traffic is done).

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Using the algorithms it is possible to compute the required bandwidth. Thealgorithms allow a reasonably accurate estimation of the behaviour of anIP-link under load. It is recommended to use the required bandwidth as anupper bound, and not a nominal operational point, for the followingreasons:

. For higher bandwidth links the resulting QoS is very sensitive to theactual load near the computed values (that is, QoS is unstable incase of operation near the resulting load point).

. The traffic patterns used for dimensioning depend on the unverifiedassumptions.

. The effective bandwidth formula used for dimensioning can only bean estimate as long as detailed information on the actualapplications is not available.

. The traffic model per user strongly depends on non-technical factorsthat are hard to incorporate into a traffic model in advance (e.g. thepricing model of the operator).

The following strategy should be used to cope with such uncertainties:

1. Calculate needed capacity C (UL+DL) for each aggregate – differentcalculations are possible for RT traffic and for nRT traffic.

2. Check that the additional delay or blocking probability is within therequired range for each aggregate.

3. The required total capacity is sum of all calculate capacities (for eachaggregate).

4. Check that the capacity fulfils any additional restrictions imposed bythe IP transport or by the node limits.

Table Capacity as function of number of subscribers for each interfaceshows overview of a capacity for different UE (Rel.5 and Rel.6) for UL andDL direction on each interface. Each of the listed capacities is the sum forelastic traffic and streaming traffic aggregates which can be calculated.

Table 21. Capacity as function of number of subscribers for each interface

UE Iub(internal) Iurs Iurd Iu-PS Gn

Rel.5 UL CUL(S) CUL((Ss) CUL((Sd) CUL(Sr+i) CUL(So)

DL CDL(S) - - CDL(Sr+i) CDL(So)

Rel.6 UL CUL(S) - - CUL(Sr+i) CUL(So)

DL CDL(S) - - CDL(Sr+i) CDL(So)


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The following is valid for the above listed capacities:

.

Two approaches can be used to calculate needed capacity for eachaggregate:

Method 1: Perform a simple calculation of the generated traffic (from thetraffic model) and then add sufficient amount of spare capacity (to fulfilQoS requirements). This can result in over provisioning.

Method 2: Use Erlang (Erlang-B and Erlang-C) formulas. For moreinformation, see Elastic traffic (non Real Time) dimensioning algorithm andStreaming (Real Time) traffic dimensioning algorithm.

Resource dimensioning Using Erlang-B and Erlang-C gives good resultsand can be used for capacity dimensioning. The choice of the formuladepends on the handling of subscribers when all resources are busy.

Erlang-B should be used when a failure to get a free resource results inrejected service. The request is rejected since no free resources areavailable (in case of CAC). This should be used for RT traffic where themain requirement is for service if it is rejected (not enough resources) oraccepted. Guaranteed bit rate for the service has to be provided (if serviceis excepted, define guaranteed bit rate has to be available).

Erlang-C should be used when a failure to get a free resource results inservice delay (packets being added to a queue). The packet stays in thequeue until free resources are available. This should be used for nRTtraffic where requested service can be delayed (packet arriving withdelay). The service is not rejected but the QoS requirements can bedecreased.

8.2.4.1 Elastic traffic (non Real Time) dimensioning algorithm

The elastic traffic is treated as an aggregate of non real time trafficapplications. The traffic model allow to find out the average throughput persubscriber, or it should be possible to calculate this average throughputper subscriber.

Capacities required for the elastic traffic aggregates can be calculated bymethod 1 or method 2.

Method 1:

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1. Check for input values as listed in Table List of input values (elastictraffic, Method 1):

Table 22. List of input values (elastic traffic, Method 1)

Elastic traffic

Values Unit Formula

Number of subscribers - Nsub

Ratio UL:DL

Uplink

Downlink

%

%

rau

rad

Throughput persubscriber

kbps Trsub

2. Calculate load generated by all subscribers, for DL and UL.

Table 23. Calculation of traffic generated by all subscribers (elastic traffic,Method 1)

Elastic traffic

Values Unit Formula

Generated traffic kbps Tr = Trsub * Nsub

Uplink kbps TrUL = Tr * rau

Downlink kbps TrDL = Tr * rad

3. Calculation of required capacities:

A required capacity depends on the generated traffic (calculated inprevious step) and utilisation p which can add additional sparecapacities needed to fulfil possible QoS requirements.

Table 24. Required capacities (elastic traffic, Method 1)

Elastic traffic

Values Unit Formula

Utilisation % ρ


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Table 24. Required capacities (elastic traffic, Method 1) (cont.)

Elastic traffic

Values Unit Formula

Required capacities

Uplink

Downlink

kbps

.

.

.

Method 2:

1. Check for the input values as listed in Table List of input values(streaming traffic, Method 2):

Table 25. List of input values (streaming traffic, Method 2)

Elastic traffic

Values Unit Formula


Ratio UL:DL

Uplink

Downlink

%

%

rau

rad

Throughput per subscriber kbps Trsub

Peak Throughput

uplink

downlink

kbps

rpeak,UL

rpeak,DL

Additional delay % x

2. Determine/compute the total offered loads Tr for elastic traffic.

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Table 26. Calculation of traffic generated by all subscribers (streaming traffic,Method 2)

Elastic traffic

Values Unit Formula

Generated traffic kbps

.

Generated traffic

Uplink

Downlink

kbps

kbps

.

.

3. Compute the required bandwidth Creq to fulfil the delay targets:

For a given offered load Tr, a single rate limit rpeak, and a delay factorf >1 the required bandwidth Creq has to be computed.

The delay factor f of the M/G/R-PS queue can be expressed as:

. Equation 3

where p = Tr/Creq and R =Creq/rpeak. The function E2 is Erlang'ssecond formula (Erlang C formula). It is defined as:

. Equation 4

Table 27. Required capacities (streaming traffic, Method 2)

Elastic traffic

Values Unit Formula

,


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Table 27. Required capacities (streaming traffic, Method 2) (cont.)

Elastic traffic

Values Unit Formula

Delay factor -

.

Required capacities

Uplink

Downlink

kbps

.

Creq,UL

Creq,DL

Sum of UL and DL capacities can be taken to check limitations of thenode (I-HSPA adapter). For interface it is enough to take intoaccount only the bigger value (in case of web browsing it is DL),especially when Ethernet interfaces are used. The reason behind itis that the Ethernet interfaces are duplex, which would mean that inthe case of 1 Gbps Ethernet, 1 Gbps would be available for DL and 1Gbps for UL.

4. Compute C such that utilisation target is fulfilled too.. Compute limiting utilisation Plimit = Tr/Creq based on delay

requirement.. The resulting link bandwidth C is the one with the smaller

utilisation:. C = Creq if the limit utilisation plimit is less than the maximum

utilisation pmax.. C =Tr/Pmax otherwise.

8.2.4.2 Streaming (Real Time) traffic dimensioning algorithm

For RT traffic, calculation is different than for nRT traffic. The basicdifference is the type of QoS requirements.

Method 1:

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1. Check for input values as listed in Table List of input values(streaming traffic, Method 1):


Streaming traffic

Values Unit Formula

Number ofsubscribers

- Nsub

Bandwidth per call kbps Trcall

Ratio UL:DL (forVoIP)

- 1

BHCA 1/BH λ

Call duration s 1/µ

Peak Throughput

uplink

downlink

kbps

rpeak,UL

rpeak,DL

maximum bitrate kbps rmax

guaranteed bitrate kbps rg

blocking probability % B

2. Calculate load generated by all subscribers.

Table 29. Calculation of traffic generated by all subscribers (streaming traffic,Method 1)

Streaming traffic

Values Unit Formula

Traffic in Erlang per subscriber Erlang

.

Traffic in Erlang Erlang

.


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3. Calculation of required capacities:

A required capacity depends on the parallel calls and requiredbandwidth per call.

Table 30. Required capacities (streaming traffic, Method 1)

Streaming traffic

Values Unit Formula

Utilisation % p

Offered load kbps

.

Required capacities kbps

.

Method 2:

1. Check the input values as listed in Table List of input values(streaming traffic, Method 2) together with QoS requirements definedas blocking probability:


Streaming traffic

Values Unit Formula


Bandwidth per call kbps Trcall

Ratio UL:DL (for VoIP) - 1

BHCA 1/BH λ

Call duration s 1/µ

Peak Throughput

uplink

downlink

kbps

rpeak,UL

rpeak,DL

maximum bitrate kbps rmax

guaranteed bitrate kbps rg

blocking probability % B

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2. Determine/compute generated load in Erlang for all subscribers, andthe effective bitrate:

Table 32. Calculation of traffic generated by all subscribers (elastic traffic,Method 2)

Streaming traffic

Values Unit Formula

Traffic in Erlang per subscriber Erlang

.

Traffic in Erlang Erlang

.

Effective bitrate kbps

. , with 0≤f ≤1

It is suggested to use a factor f in the range of 0.25 to 0.5. Highervalues account for more conservative dimensioning.

3. Compute C such that the blocking rates for all classes are fulfilled.. Compute a (the offered stream traffic) according to Equation 6.

This is also a lower bound for the required link capacity.. Using the approximation given in Equation 5 or the

multidimensional Erlang theory the blocking probability Bi canbe computed for each class with a peak bandwidth rmax (for afixed total bandwidth c). Starting with a and increasing C untilall blocking probability targets Bi are fulfilled.

An approximation (not an upper bound!) for the blocking probabilityBi of a flow with peak rate rmax when C is large with respect to ei isgiven by:

. Equation 5

where


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. Equation 6

The function E(a,n) is Erlang's formula (Erlang B formula).

. Equation 7

The parameter a denotes the offered load whereas the parameter δis the mean of the effective bandwidths (weighted). Thus the ratio a/cdenotes the link utilisation. Moreover, since the blocking probabilityis given by an Erlang B formula the same well-known scaleeconomics is available. This suggests that the ratio C/δ should behigh. Therefore, in order to achieve a link high utilisation it isnecessary to have a high capacity C in comparison to the averageeffective bitrate.

and

n

!

.

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