Nemo Drive Test on 2G/3G

Networks

Toha Ardi Nugraha Trainer at Expert Coaching Clinic

Network Optimization Process

Reason of Drive Test?

1. Network Performance Monitoring

2. Maintenance

3. Benchmarking

4. Customer Complains

• Module 1 : Overview 3G System (1 hour)

• Module 2 : Drive Test Concept (1,5 hour)

• Module 3 : Drive Test on Field (2,5 hour)

• Module 4 : Reporting (2 hour)

• Module 5 : Analysis (2 hour)

OVERVIEW 3G SYSTEM

Module 1

Data Transmission

GSM & UMTS Evolution

3G/UMTS Architectures (Migration)

Specification of GSM

• Frequency band :

Uplink 890 – 915 Mhz

Downlink 935 – 960 Mhz

• Duplex spacing : 45 Mhz

• Carrier spacing : 200 khz

• Modulation : GMSK

• Access method : FDMA / TDMA

GSM network Architecture (cont’d)

• 3 Subsystem in GSM network

- BSS (Base Station Subsystem)

- NSS (Network and Switching Subsystem)

- OSS/OMC (Operating and Support system or

Operating and Maintenance Centre)

GSM network Architecture (cont’d)

BSS (Base Station SubSystem)

• BTS (Base Transceiver Station)

- Radio equipment

- To transmit and Receive signal to MS

- Defined a Cell coverage

depend on the power transmit

• BSC (Base Station Controller)

- RRM for several BTS

- Handover management

• TRAU

- Rate adaption

GSM network Architecture (cont’d)

NSS (Network and Switching Sub System)

• MSC (Mobile Switching Centre)

• HLR (Home Location Register)

• VLR (Visitor Location Register)

• AuC (Authentication Center)

GSM network Architecture (cont’d)

Operation and Support System

• Control and Monitor the Network

- NMC (Network Management Centre)

- Some OMC are controlled by NMC

- OMC (Operation and Maintenance Centre)

GSM Frequency Bands

GSM type Frequency Band

Uplink (UL) Downlink (DL)

GSM 900 890-915 Mhz 935-960 Mhz

GSM 1800 (DCS 1800) 1710-1785 Mhz 1805-1880 Mhz

GSM 1900 (PCS 1900) 1850-1910 Mhz 1930-1990 Mhz

GSM Channelization

• Physical Channel

– 200 Khz (Frequency Carrier) consist of 8 TS

• Logical Channel

– Control Channel

– Traffic Channel

Control Channel

Traffic Channel

GSM channelization (Cont’d)

Logical channel

Chontrol Channel

Broadcast channel

Common Control Channel

Dedicated Control Channel

Traffic Channel

Full Rate Half rate

3G/UMTS Concept

• WCDMA Concept

• UMTS Architecture

• Channelization

• Handover

WCDMA - Wideband CDMA

• Radio access technology for one of the UMTS access

modes (UTRA FDD) using 5 MHz duplex channels.

– Frame length is of 10 msec, Chip rate is 3.84 Mcps

– All users share the same frequency and time domain

– Users separated by the codes

UMTS Radio Frequency Ranges

• FDD (Frequency Division Duplex)

• TDD (Time Division Duplex)

Channelization in UMTS

• Logical Channel between RLC

and MAC

– Specific for information types

– What type of data to be

transferred

• Transport channel between MAC

and PHY

– Specific for “how to transfer

information?” (quality guarantee)

– How and with which type of

characteristic the data is

transferred by the Physical

Layer

• Physical Channel – Exact Physical characteristics of the

radio channel

WCDMA Channel (Cont.'s)

• Spreading means increasing the signal bandwidth

• Spreading includes two operations – Channelization (increases signal bandwidth)

• Orthogonal Spreading

– Scrambling

(does not affect the signal bandwidth) • Use pseudo-noise codes

Handover Concept

Site B Site A

BSC

Posisi 1

Posisi 2

Posisi 3

Handover

Request

Handover

Request

Handover Req

Acknowledge

Handover Req

Acknowledge

Handover Req

Acknowledge

Handover

command Handover

Complete

Handover: Types (2G)

• Intracell handover

– MS moves from one sector to another sector within same cell

• IntraBSC handover

– MS moves from cell to another cell within same BSC

• IntraMSC handover

– MS moves from cell to another cell from different BSC within same MSC

• InterMSC handover

– MS moves from cell to another cell from different BSC and different MSC

Handover: Types (3G)

• Intra-System handovers

– Intra-frequency handovers

• Soft, Softer

– Inter-frequency handovers

• Hard

• Inter-System handovers

– Handover between

WCDMA <> GSM (Hard)

– Handover between

WCDMA/FDD <> TDD

(Hard)

Pilots Set

The handset considers pilots in sets

– Active : pilot of sector actually in use

– Candidate : pilots mobile requested,

but not yet set up & transmitting by

system

– Neighbors: pilots told t mobile by

system, as nearby sectors to check

– Remaining: any pilots used by system

but not already in the other sets

Soft Handover Algorithm

AS_Th – AS_Th_HystAs_Rep_Hyst

As_Th + As_Th_Hyst

Cell 1 Connected

Event 1A

Add Cell 2

Event 1C

Replace Cell 1 with Cell 3

Event 1B

Remove Cell 3

CPICH 1

CPICH 2

CPICH 3

Time

Measurement

Quantity

T T T

DRIVE TEST CONCEPT

Module 2

Network Environment

• UMTS Drive Test is testing and measuring performance of

3G/UMTS network.

• Tools :

1. Software Nemo Outdoor

2. PC laptop

3. GPS

4. Scanner

Reason of Drive Test?

• Network Performance Monitoring

• Maintenance

• Benchmarking

• Customer Complains

Continuous Drive Test

• Drive Test (outdoor)

– GPS

• Walk Test (indoor)

– Pin point/way point

Analyze Data Collection

• Analyze data that was collected before

(from Log files)

• To know some problems in current area

Reporting

• To Answer Analyze Data Collection (Objective

Answer)

• Optimization Consideration

• Recommendation

Parameters DT GSM

1. Rx Level

2. Rx Qual

3. SQI

4. Cell Id, BSIC

5. TA (Timing Advance)

6. ARFCN, etc

Parameters DT UMTS

• UARFCN (UMTS Absolute Radio Frequency Channel

Number)

• RSCP (Receive Signal Code Power)

• RSSI (Receive Signal Strength Indicator)

• SC (Scrambling Code)

• Ec/No

• UE TxPower (dBm)

• Throughput

• BER, etc

• Step 1:

Start >“Settings”> “Control

Panel” > “System”

Or “My Computer” >

“Manage” > “Device Manager”

Open Device Manager

• Step 2: Choose “Hardware”

Tab in System Properties >

Click “Device Manager”.

Open Device Manager

• Step 3 :

• Look port to

conect hardware

(Modem)

• Scanner/GPS &

Check COM

Ports

Connect UE & Check COM Ports

• Double click the “3G

Modem” to check Trace

port number > Check

under “Modem” Tab.

• For UE Modem:

– In device manager

view:

Start Nemo Outdoor 5.07 and Load

Workspace

• Make sure the Nemo dongle is connected to the laptop.

• Launch Nemo Outdoor 5.07.

• Load the desired workspace.

• Workspace should contains adequate information for the

user to monitor.

• Different workspace should be created for different setup

configuration.

• Nemo workspace are stored proper folder for easy

access, eg.

C:\Nemo Tools\Nemo Outdoor\Workspaces

Running Program

Start >Program Files > Nemo Tools > Nemo Outdoor 5

• Workspace

• Details

• Device Configuration

• Load a measurement

User Interface Nemo Outdoor 5

Worksheet

Device graph

Load Workspace

• Step 3: Browse to Nemo Workspace Folder -> Select “workspace” >

Click “Open”.

Create Workspace

• Parameter

Add Devices

• Step 1: Go to “Measurement” workspace > “Add New Device”.

• Step 2: Click the “Configuration” part

> “Trace port” and “Modem port”

Nemo Interface

• Map Interface

– Open map (.tab)

• Nemo logfiles and other files are stored proper folder for easy

access, eg.

C:\Nemo Tools\Results (.nmf)

DRIVE TEST ON FIELD (OUTDOOR)

Module 3

REPORTING

Module 4

Map Info

• Exporting from Nemo Outdoor

– Select Parameters

• Reporting KPI with Map Info

• Layer Control

– Symbol

• Create Thematic Map

• Define Network Performance

• Open Table

Export to Map Info

Select Parameters

Report KPI With Mapinfo

• KPI (Key Performance Indicator) : key to detemaint Network performance.

like as , RSCP, Ec/No, etc

• Mapinfo is Software for loading and mapping geogharphic analysis

• File > open file (chose file

extention .tab)

• Ex : bandung.tap

• Used Layer control

Open Log files

• Example file (.tab)

Layer Control

• Command:

– View

– Edit

Create Symbol

Create Thematic Map

Create Thematic Map (Cont.'s)

Create Thematic Map (Cont.'s)

Reporting with Map Info

Open Table

ANALYSIS (TUNING THE NETWORK)

Module 4

UMTS Optimization

• 3 Mayor Steps in Optimizing Network

• UMTS performance indicator

• Problem Signature

• Tuning network

– Specific Neighbor list

– Managing excessive soft handoff

3 Mayor Steps in Optimizing Network

• RF optimization is the process of measuring,

• analyzing, and tuning and existing network to meet

network performance criteria

• It usually occurs after the network planning is completed

• It can be performed frequently to respond:

– Changes or growth in the network

– Customer complaints such as coverage,

dropped call etc.

– The need to improve capacity.

UMTS Performance Indicator

KPI Target :

– RSCP (good > -85 dBm)

– Ec/No ( > -8 dB)

– BER (98%)

– Analyze Pilot Pollution Area

– Drop Call Rate (DCR)

– HSR (Handover Success Rate)

– Call Setup Success Rate (CSSR)

Problem Signature

• Missing Neighbor or No Neighbors defined for

Site. (Database)

• Poor Coverage Area.

• Pilot Pollution Area

Poor Coverage Area

• Test mobile measurements

• Antenna configuration check

• Verification of RF network design

• Propagation model verification

• Link budget analysis

Improving coverage

– Cell spliting, Sectorisation

• Difficult , Expensive

• Primarily used for capacity enhancement

– Overlaid cell structure

• Micro- and picocells

• Cellular repeaters

RNC

Node B

Node B

Node B

Node B

Pilot Pollution

• Active set UE > 3 and in range 5 dB or approximately 3

dB from the biggest active set.

• Reduce system performance,

Antenna Fine Tuning

• Horizontal plane

– Possible coverage weakness between sector

– Interference reduction

– Traffic load distribution

• Vertical Plane

– Interference reduction

– Possible coverage weakness in the short to medium

distance range

– Traffic load distribution

Tuning the Network

Solution (Antenna Adjustments)

Include :

– Down tilting

– Antenna Height

– Azimuth

– Type of antenna

Reason of Down tilting:

1 Reduce interference

2 Optimizing cell

Antenna Configuration

• General points to check

– antenna type, e.g.

• omni

• directional 60, 90 or 120 degrees

• electrical downtilt

– antenna azimuth angle (for directional antenna)

• coverage targets

– antenna tilt angle

• electrical + mechanical

– diversity & isolation

• e.g. space diversity,

• polarisation diversity

Type Antenna Down tilt

Mechanical down tilt

– Physic, Sectoral

Electrical down tilt

– Easy

0 ° 0 °

Electrical Mechanical

Typical antenna beam pattern

Omni vs. Sectorised

• OMNI cells - more difficult to optimize – Electrical down tilt possible, however

• same for entire cell

– Parameters same for entire cell

• Directional antenna – narrower beam easier to control interference

– tilting less efficient with wider beams

Sectorised cell site with different

downtilt angles

Reference

• Short Course “In Building DCS 1800 Coverage”, Mobile

Communication Laboratory, 2009

• Short Course “Drive Test UMTS”, Mobile Communication

Laboratory, 2008

• Short Course “Drive Test CDMA 2001x and Optimization”, Mobile

Communication Laboratory, 2008

• Short Course “CDMA Drive Test and Optimization”, Antenna

Laboratory, 2007

• Nemo_Outdoor_manual

Thanks