microsoft power point - 7 omf000602 network planning principle issue2

8/14/2019 Microsoft Power Point - 7 OMF000602 Network Planning Principle ISSUE2

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www.huawei.com

Copyright 2006 Huawei Technologies Co., Ltd. All rights reserved.

Network Planning Principle


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Page2Copyright 2006 Huawei Technologies Co., Ltd. All rights reserved.

Foreword The performance of GSM network is mainly based on the

topology structure and parameter planning, so suitableplanning can save investment, ensure the acceptable index

and decrease optimization working


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Objectives Upon completion of this course, you will be able to:

Know principle of propagation

Grasp the feature of antenna

Plan coverage and capacity

Master the flow of network planning


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Contents1. Planning Basis

2. Coverage Planning

3. Capacity Planning

4. Advance Planning

5. Procedure and Site Location


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1.1 Fundamental to GSM Network

1.2 Mobile Radio Link


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GSM BandwidthGSM 900 :

Channel spacing 200kHz,124 carriers

GSM 1800 :

Channel spacing 200kHz,374 carriers

1710 1785 1805 1880

Duplex Spacing : 95 MHz

890 915 935 960

Duplex Spacing : 45 MHz


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The Frequency Spectrum

Fd(n)=Fu(n)+80512


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Requirement for C/IRequirement for C/I

All useful signals carrier

All useless signals interference

=

GSM standard: C / I >= 9 dB

In practical projects: C / I >= 12dB

Useful signal Noise from environment

Other signals

C/I =


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Effects of Interference Affect signal quality

Required C/I

Co-Channel C/I: 9dB

The first adjacent Channel C/I: -12dB

The second adjacent Channel C/I: -41dB


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Signal Quality in GSMRX QualityRXQUAL class : 0 ... 7

RXQUAL Mean BER BER range

class (%) from... to

0 0.14 < 0.2%1 0.28 0.2 ... 0.4 %2 0.57 0.4 ... 0.8 %3 1.13 0.8 ... 1.6 %4 2.26 1.6 ... 3.2 %5 4.53 3.2 ... 6.4 %

6 9.05 6.4 ... 12.8 %7 18.1 > 12.8 %

usable signal

unusablesignal

good

acceptable


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Interference Sources Multi-path (long echoes)

Frequency reuse

External interference

Note : Interference has the same effect as poor coverage.

Reduce the interference

as possible.


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Methods for Reducing Interference Frequency planning

Suitable site location

Antenna azimuth, downtilt and height

Frequency hopping

Power control based on quality

Evaluate signal level and quality

DTX

Silent transmission in speech pauses

Adaptive channel allocation

Always assign the best available channel during call setup.


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Cell Evolution

Umbrella Cell5-50Km

Early 80s

Macro Cell1-5Km

Mid-end 80s

Micro Cell100m-1Km

Mid 90s

Pico Cell10m-100m

Mid-end 90s

Macro Cell Layered Network


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Layered Network

High layer station

Middle layer station

Middle layer station

Indoors station

Indoor station

Indoors station

Low layer stationLow layer station

Low layer stationLow layer station

Indoors station


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Macro Cell Network Cost performance solution

Suitable for covering large area Large cell range

High antenna position

Cell ranges 2 ..20km

Used with low traffic volume

Typically rural area

Road coverage

2..20km


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Micro Cell Network Capacity oriented network

Suitable for high traffic area

Mostly used with beamed cell

Cost performance solution

Usage of available sites equipment

Typical application

Medium town

Suburb Typical coverage range: 0.5 .. 2km

0,5 .. 2km


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1.1 Fundamental to GSM Network1.2 Mobile Radio Link


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Radio Link Propagation Multi-path propagation

Radio path is a complicated propagation medium

Limited transmitting energy

The service range is determined by the transmission power of mobiles

Battery life-time

Limited spectrum

Set upper limitation for data rate (Shannons theorem)

Additional effort needed for channel coding

Frequency reused result in self- interference


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Radio Propagation Environment Multi-path propagation

Shadowing

Terrain

Building

Reflection

Interference


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Fading Slow fading (Lognormal Fading)

Shadowing due to large obstacles on propagation direction

Fast fading (Rayleigh fading)

Serious interference from multi-path signals

+10

0

-10

-20

-300 1 2 3 4 5 m

Level (dB)

920 MHzv = 20 km/h


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Fading

time

power

2 sec 4 sec 6 sec

+20 dB

meanvalue

- 20 dB

lognormal

fading

Rayleigh

fading


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Land Usage Types Urban small cells, 40..50 dB/Dec attenuation

Forest heavy absorption; 30..40 dB/Dec; differs withseason (foliage loss)

Open, farmland easy, smooth propagation conditions

Water propagates very easily ==> dangerous !

Mountain surface strong reflection, long echoes

Hilltops can be used as barriers between cells, do notuse as antenna or site location


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What is Diversity Receive diversity provides an effective technique for both

overcoming the impact of fading across the radio channel

and increasing the received signal to interference ratio

The former is achieved by ensuring uncorrelated (i.e. low

enough correlated) fading between antenna branches i.e.not all antennas experience fades at the same time


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Diversity Time diversity

Coding, interleaving

Frequency diversity

Frequency hopping

Space diversity

Multiple antennas

Polarization diversity

Dual-polarized antennas

Multi-path diversity

Equalizer

t

f


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2. Coverage Planning3. Capacity Planning

4. Advance Planning



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Link Budget


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Link Budget Model

receivemsbtscablebts MinGLGLP ++

npenetratioinminminmmsreceive LFastFadingngSlowlyFadiISMin ++++= argargarg

receivecablebtsdiversitynpenetratiomsms MinLGGLLGP +++

inminminmbtsreceive FastFadingngSlowlyFadiISMin argargarg +++=

On downlink

On uplink


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Equipment-related Parameters BTS Tx power

Maximum BS Tx power.

Maximum power of the antennaPtrx-Lcdu

Maximum MS Tx power

900:2W

1800:1W BS antenna gain

Typical value: Omni directional antenna: 11dBi or 13dBi;directional antenna: 15 to 18dBi.

MS antenna gain

Generally, MS antenna and the connection loss areconsidered to be 0dB.


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Equipment-related Parameters BTS receiver sensitivity

900:-110dBm

1800:-109dBm

The sensitivity is also related with vendor and environment

MS receiver sensitivity

-102dBm

BTS feeder and connector loss The feeder loss is related to the signal frequency and length.

The connector loss is approximately 0.2dB.

17.7 dB/100m

4.77 dB/100m

6.46 dB/100m

2000MHz

11.2 dB/100m7.6 dB/100m1/2 inches

2.98 dB/100m1.9 dB/100m5/4 inches

4.03 dB/100m2.7 dB/100m7/8 inches

800MHz450MHzFeeder types

Frequency


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Margin Fast fading margin: typical value 3dB

Interference margin: typical value 3dB Slowly fading margin: typical value: 3--10dB

The path loss value obtained from the link budget is the

median. Due to the shadow fading, the actual path loss

fluctuates around this value. It is subjected to the logarithmic

normal distribution as the location and time varies To ensure a

certain edge coverage probability (generally > 75%), it is

necessary to reserve some power margin, i.e. the shadow

fading margin.


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Margin According to the standard deviation of the shadow fading and

the requirements for the border coverage probability

(determined by the operator), we can calculate the shadowfading margin by

Mf (dB value)= NORMSINV (Border coverage probability) r

where NORMSINV ( ) is the inverse function of the standard normal

distribution accumulation function. The 75% border coverage

probability is corresponding to 0.68. r is the standard deviation of

shadow distribution. Generally, when the frequency is 800MHz, thisvalue is 6-8dB in quasi plain urban areas.

Note : the 75% border coverage probability is corresponding to the

90% area coverage probability.


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Min. Receive Level

Sms=-102dBmFast Fading Margin=2dB

Slowly Fading Margin=5dB

Interference margin=2dB

-93dBmOutdoor

Sms=-102dBm

Fast Fading Margin=2dB



Penetration Loss=13

-80dBmResident area, indoor

Sms=-102dBm

Fast Fading Margin=2dB



Penetration Loss=18

-75dBmDensity urban, indoor

GivenMin. Receiving LevelApplication Environment


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Balance Function

btsdiversitymsmsbts SGPSP +=

Why is not related to loss of cable?


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Site Coverage Radius: R

Site distance: D=1.5R

Coverage Area=1.949R2

Site Coverage Radius: R

Site distance: D=1.732R

Coverage Area=2.598R2

3 Sectors site Omni siteDistance and Coverage Area


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Amount of BTS Evaluate achievable cell coverage range

Radius=f (topography, requirements, environment, ...)

Coverage Area=F (radius, sort)

Number of BTS needed for coverage reason:

desire area/area per site


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4. Advance Planning



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How Many Subscribers can a Cell Support?

Traffic volume generated by subscriber and distribution

(amount of subscriber and load per user in busy hour)

GOS: Grade of Service or Block rate

Amount of TCH and signaling CH

The available bandwidth and reuse model

Channel configuration

Erlang table represent the relationship among block rate,traffic volume and number of CH


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Channel Configuration One BCCH is needed for one cell

It is suggested that one SDCCH/8 is needed for two TRX

For example:

There are 3 TRX in certain cell, therefore, the below channel

should be configured: One BCCH, Two SDCCH/8, Twenty one

TCH


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Erlang Table

Block RateSum of

CH

30.6623.83

16.19

9.730

3.738

2.960

5

34.5027.3425.5124.013627.0521.0419.4918.2229

18.6514.0412.8411.8621

11.478.2007.5326.66314

4.6662.9352.5012.1587

3.7582.2761.9091.6226

1021.00.5


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Estimate Number of BTS Needed

Given: amount of subscriber, bandwidth available,

reused density, traffic model

total operators bandwidth/planned freq. reuse rate

==>number of TRX per cell

==>channel per cell

==>subscriber per cell

==>number of BTS needed for traffic reasons

VERY rough initial estimation!


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How Many Subscribers should a Cell Support?

Given: Number of subscribers in area, Traffic load per subscriber,

Coverage area, radius

Total traffic volume

==> traffic per sq.km

==> traffic per cell

==> number of TRX needed per BTS

Allow extra capacity for roamer and busy hour traffic

Transmission should not be thebottleneck of the system


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Contents

1. Planning Basis



4. Advance Planning



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Why Indoors

Indoor coverage become the main competition between operators

Subscribers expect continuous coverage and better quality

Outdoor cell cant provide sufficient indoor coverage

INDOOR SOLUTION

GoodQuality!


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Building Penetration Loss

Signal level in building is estimated by using a building

penetration loss margin

Big differences between rooms with window and without

window(10~15 dB)

rear side :-18 ...-30 dB

Pref = 0 dB

Pindoor = -3 ...-15 dB

Pindoor = -7 ...-18 dB

-15 ...-25 dB no coverage

signal level increases with floor

number :~1.5 dB/floor (for 1st..10th floor)


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Building Penetration Loss

Signal loss for penetration varies between different building

materials, e.g.:

mean value

reinforced concrete wall, windows 17 dB

concrete wall, no windows 30 dB

concrete wall within building 10 dB

brick wall 9 dBarmed glass 8 dB

wood or plaster wall 6 dB

window glass 2 dB

Total building loss = median valuesmargin (lognormal) for higher probabilities


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In-Building Path Loss

Simple path loss model for in-building environment

Outdoor loss: Okumuras formula

Lout = 42,6 + 20 log( f ) + 26 .. 35 log( d )

Wall loss

Lwall = f (material; angle)

Indoor loss: linear modelFor Pico-Cells

Lin = L0 +(loss per meter)*d

building type loss application example old house 0,7 dB/m (urban l)

commercial type 0,5 dB/m (modern offices)

open room, atrium 0,2 dB/m (museum, train station)

Lout

Lwall

Lin


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Indoor Coverage Solutions

Small BTS

Mini BTS

Repeater

Active

Passive

Optical

Antennas

Distribute antenna

Leaky cable

Signal distribution

Power splitter

Optical fiber


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Indoor Planning

Example2:

1.2 MHz allocation50 mErl/subscriber , GOS=2%reuse per two floor, separatefrequencies within one floor:a) three floors

52.12 Erl => 842subsb) ten floors

140 Erl => 2808 subs

Example1:

1.2 MHz allocation50 mErl/subscriber, GOS=2%no frequency reuse:

a) three floors

34.68 Erl=> 694 subscribersb) ten floors

34.68 Erl => 694 subscribers

Single cell approach Multi-Cell approach

t

f5

f6

f5

f1

f2

f1

f3

f4

f3f1..f6

f1..f6

f1..f6


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Repeater According to operating frequency

Wide-band Repeater

Narrow-band Repeater

According to working method

Passive Repeater

Needs strong external signal, useful only with very short cables and seldom

used

Active Repeater

Amplify and re-transmits all received signals

Application examples

Coverage for low traffic area

Remote valley

Tunnel

Underground coverage

needsdecoupling > amplification


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Wave Propagation in Tunnels

Ideal antenna position: center of cross-section

Distance to walls: min. 2

Tunnel cross-section shape unimportant, if > 10

Time dispersion decreases with distance

Install antenna 50~100m before tunnel entrance

Good signal coupling between successive tunnels

Tunnels are very suitable environmentfor radio wave propagation

Tunnels are very suitable environmentfor radio wave propagation

C S


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Tunnel Cross-Section

Filling factor determines propagation condition

Typical range for filling factors

Road tunnels: 10%

Metro: 60~90%

5dB margin for metro tunnel

filling factor =----------

S l i S h


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Solution Scheme

Coverage Prediction: L=20LgF+30LgD-28

Typical loss in tunnel as below

Signal source: Mini BTS, Repeater

Distribution system: Cable, Leakey cable and Directional antenna

111.4dB105.3dB300m

106.1dB100.1dB200m

102.1dB96.3dB150m

97dB91dB100m

88.1dB82dB50m

1800MHz900MHzDistance

L ti A D i


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Location Area Design

Location update affects all mobiles in network

Location update in idle mode

Location update after call completion

Location update brings extra burden to the network

Good location area design should avoid ping-pong

location update

Paging ability is limitation of location area

Location area 1

Location area 2major road

LA D i


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LA Design

Paging blocks per second X Paging message per

block=Paging message per second

==>Paging message per hour

==>Traffic volume per Location area

==>Sum of TRXs per Location area

It is related to traffic model!


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Scope of Net ork Planning


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Scope of Network Planning Network design

Number & configuration of BSC

Antenna specifications

BSS topology

Frequency plan

Network evolution strategy

Network performance prediction

Gos

Margin calculations

Interference probabilities

Quality observation

Planning Flow


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End

Information collection

Preparation for planning

Nominal planning

Interference measurement

RF site survey

Frequency planning

Propagation mode tuning

parameter planning

Data configuration

Start

g

Contents of Information Collection


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quality costcapacity

You can get a balanced network

coverage

Contents of Information Collection

Operators requirements Subscriber forecasts Coverage requirements

Quality of service Recommended sites

External information Terrain data

Population data Bandwidth available

Preparation for Planning


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Preparation for Planning Population distribution in serving area

Road condition and paper map

Digital map

Service area visit

Link budget

Traffic distribution

Nominal Planning


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Nominal Planning Presume site location

Coverage predication

Frequency planning

Interference analyze

Traffic prediction

Interference Measurement


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Interference Measurement

Use spectrum analyzer to scan the interference and confirm

the exact RF resource can be used.

Propagation Model Tuning


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Model Error Distribution

-1000

0

1000

2000

3000

4000

5000

6000

-48 -44 -40 -36 -32 -28 -24 -20 -16 -12 -8 -4 0 4 8 12 16 20 24 28 32 36 40 44 48

Error (dB)

NumberofBins

tuned Non-tuned

Propagation Model Tuning

To make a accurate coverage planning, propagation model

tuning is necessary.

Site Location


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Site Location

Cell performance has a close relationship with site location

Site is long-term investment

Site acquisition is a slow process

Hundreds of sites needed per network

Site is a valuable long-termasset for the operator

RF Site Survey


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RF Site Survey Site location confirmation

Cell capacity confirmation

Antenna selection

Antenna installation position

Antenna height, azimuth and downtilt

Bad Site Location


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Bad Site Location

Avoid hill-top location for site

Uncontrollable interference

Cross coverage

Bad handover behavior

wanted cellboundary

uncontrolled, stronginterferences

cross coverage areas:

Good Site Location


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Good Site Location

Prefer site off the hill-top

Use hill to separate cell

Contiguous coverage area

Need only low antenna height if site are slightly elevated

above valley bottom

wanted cellboundary

Site Selection Criteria


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Site Selection Criteria

Radio criteria

Good view in main beam

direction

No obstacles

Good visibility of terrain

Antenna installation situation

LOS to next microwave site

Short feeder length

Non-radio criteria

Space for equipment

Availability of leased

transmission line or

microwave link

Power supply

Access restrictions

House owner

Rental costs

Site Information


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Site Information

Questionnaire

Site coordinates, height above sea level, exact address

Type of building Building materials

Possible antenna heights

360deg photo (clearance view)

Neighborhood, surrounding environment

Drawing sketch of rooftop

Antenna installation conditions

BTS location, approximately feeder lengths

Frequency Planning Adjust and


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OK! Set the data

to the BSC

CDD Planning BCCH,BSIC,TCH planning

Frequency hopping planning

Interference analysis Cell data design

BSS Parameters


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SS a a ete s BSS Relevant Parameter for Network Planning

Frequency allocation plan

Logical radio configuration

Transmitting power

Definition of neighboring cells

Definition of location areas

Handover parameters

Power control parameters

Cell selection parameters

Radio link time-out counter

Topology of BSC- BTS network

Summary


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y

In this course, we have learned:

Propagation and planning basis

Coverage planning method

Capacity planning method

Indoor and tunnel planning

Planning procedure and site location


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Thank youwww.huawei.com

microsoft power point - 7 omf000602 network planning principle issue2

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