Training_DriveTest & Optimization

8/10/2019 Training_DriveTest & Optimization

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Main Tools for Radio Network

Optimization GSMStatistic Handling Tool

OSS Recording Tool

Cell Data Design Tools

Field Measurement

Cell Planning Tool

Field Measurement Analysis

NWS (C); SPOS&Turle, Statics (I)

PMR, RNO package (C)

CNA (C); IPOS, BSSTool (I)

TEMS only!!!

TEMS Cellplanner (C); MCOM (I)

TEMS, MapInfo (C); MCOM (I)


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Radio Network Growth Flow


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Model Tuning

Network Integration Test

Design & Rollout

Initial Tuning

Training

Operation & Improvement

Verification of Network Changes

Network Feature Optimization

Traditional Optimization

GPRS Performance

Verification

Where does TEMSINVESTIGATION fit in


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Network Integration Test

When a site is integrated to BSC it is tested

Call set up test

Timeslot test, forced call test

DESIGN & ROLLOUT PHASE

* TEMS Pocket is the preferred tool for Network Integration Test


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Initial Tuning

Produce Coverage Plot

Identify Coverage Holes

Identify Interference Area

Optimize Neighbor Relations

Find Hardware/Installation Problems

Verify Parameter Setting

DESIGN & ROLLOUT PHASE


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GPRS Performance VerificationDESIGN & ROLLOUT PHASE

Application Performance Test

WWW, FTP, WAP etc.

Mobility Test

Cell Reselection, RA Update


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Network Feature Optimization

Parameter Settings:

MS, BTS Power Control

HCS

Idle Mode Behavior

Locating Algorithm

Frequency Hopping

Intra-cell Handover

OPERATION & IMPROVEMENT

PHASE


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Verification of Network Changes

Did a certain change in the network give desired results?

New coverage area?

Less interference?

Better speech quality?

Is handover possible?

OPERATION & IMPROVEMENT

PHASE


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?

Clear objective

Why should this

measurement be

done

Preparations Collect Data Analyze

Check equipment

Get input files

Prepare route

External Antenna?

Save logfile

Take notes

Monitor

Find problemareas

Find solutions

What should bechanged?

Report

Give answerto objective

Changes inNetwork

TEMS Measurement & Analyzing

Process


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?

Clear objective

Why should this

measurement bedone

Preparations

Check equipment

Get input files

Prepare route

External antenna?

Possible Objectives

Coverage analysis

Trouble shooting Scanning Verify network changes

Measurement Will Depend on

Objective


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Drive Test

Large areas

Specific areas

Walk Test

Scanning

Performing Measurements with TEMS


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INPUT

Plots & Report

- Signal Strength

- Quality

Trouble Report /

Area for further

investigation

Acceptance

New sites on air

Frequency Re-plan

BSC Re-homing

OUTPUTINPUT MEASUREMENT

Drive definedroute/area

Record Logfile

Long / Short calls

Assure no data loss

Drive Test

- Large area


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Manipulate- Forced handover

- Lock on to Frequency

- Layer 3 messages

Analysis on-spot

Rectify & Verify on-spot

OUTPUTINPUT Measurement

Statistics

Customer complain

Large area drive test

Trouble Report

Trouble Report- Identified problem

- Solution

Drive Test

- Specific area


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Finding a newfrequency

Area Network

Scanning

OUTPUTINPUT Measurement

Received SS ondifferent ARFCN

plot

New frequency

TEMS INV inscanning mode

Set ARFCN to scan

Scanning


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Analyzing Measurements


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Post-Processing TEMS Logfiles

TEMS

Logfiles

Statistics

Report

Geographical

Presentation

Analysis


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Low Signal Strength

Interference

Handover

Call Setup Failure

Dropped Call

Misc.

Problem Cases


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Signal Strength Case

INPUT

Large area DT

Specific area DT

Post-Processing

Analysis

TEMSLogfiles

Identify areas with low signal strength e.g. SS < -100dBm (outdoor)

Look at RxLev distribution (for acceptance)

Compare with design level or new requirements


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Shadowed Antenna Faulty Hardware

Height/down Tilt

Output Power

Visit site

Check antenna installation

Is there a better antenna

position at same site?

Add reduce down tilt?

Can antenna be placedlower or higher to give

better coverage?

Check output power

Parameters

BSPWRT - NON BCCH FREQ

BSPWRB - BCCH FREQ

Site Location

Possible to move site?

New antenna location atsame site? Is it necessary

to expand and build a new

site?

Check alarm & BTS Error

log

Visit site


Analysis

Missing Neighbor

Is the call dragged?

Is low SS due to missingneighbor relations


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Change parameter BSPWR , BSPWRT.

Add neighbor relation.

Physical changes:

Antenna direction

Antenna height, tilt or position

New site as last option.


Possible Solutions


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INPUT

Large area DT

Identify areas with Rxqual > 5

Identify source using Map and STS

New drive test around problem area?

Specific area DT

Post-Processing

Analysis

Interference Case

TEMSLogfiles


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From logfile & map:

What channel group suffer from interference? HOP or Non HOP?

Check Current channel information in TEMS INV, hopping

channel and hopping frequency.

Where does the interference come from? Cell name?

Study map and logfile, look for co-channel or adjacent channel

interference.

Does the interference lead to lower SQI?

Look at SQI measurement during high RxQual.

Use STS & RNO to assist analysis.

Interference Case

Logfile analysis


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BCCH 590

BCCH 590

High site

BCCH 590

BCCH 590

BCCH 595

BCCH 600 CASE 1

CASE 2

Types of Interference

Co - Channel interference

Adjacent Interference


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Poor frequency plan

No dominant cell --> low C/I ---> increased Rxqual

Frequency Hopping is off

External interference e.g. jammer

Example of high Rxqualdue to low Signal Strength

Interference Case

Possible Reasons


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Interference Case

Possible solutions Enable Frequency Hopping or add frequencies to Hopping group.

Enable BTS Power Control, MS power control and make it less aggressive.

Change frequency of interferer or interfered cell:

Possible to find new frequency by using TEMS Scanning.

Down tilt or change antenna of interferer.

Redo frequency plan.

Add new site.


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INPUT

Large area DT

Specific area DT

Post-Processing

Analysis

Look for:

Repeated handover (Ping Pong)

Repeated Intra-cell handover

Handover failure,

Unrealistic handover

Handover Case


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Repeated Handover (Ping Pong)

- Examples


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- Possible Reason 2 Offset only in one direction e.g A-B for Inter

BSC relation

CELL A CELL B

A -> B OFFSET = -5dB

BSC 2BSC 1

No B -> A OFFSET


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No dominant Server


Other Possible Reasons No dominant server

Locating penalty settings

e.g. PSSBQ, PTIMBQ Too small hysterisis

setting


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Antenna direction

Antenna Tilts

Plan for new site

Change Locating Parameter e.g.

KHYST or LHYST


Possible Solutions


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Change Parameter, KHYST or LHYST

Hysterisis

CELL A CELL B

HandoverFrom A to B


Possible Solution


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Check layer 3 message

Handover command BSC correct?

Check reason for handover SS, RXQUAL

Target cell?

Handover Case

Handover Reversion


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Duplicates of BSIC BCCH combinations in neighboring list

610_31610_31

610_12

606_33

608_32

608_32

Serving ce ll

Neighbor cell 1

Road

Neighbor cell 2

Handover command?

Handover Reversion

Common Reason


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Uplink interference in target cell

Downlink interference at MS

Solutions

Interference Investigation

MRR

Statistics

Scanning

Handover Reversion

Other Reasons


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Possible Reasons

Wrong intra-cell handover settings

External Uplink Interference

Possible Solutions

Consider to change parameters:

SSOFFSETUL, SSOFFSETDL

QOFFSETUL, QOFFSETDL

A wrong setting of parameters will cause unnecessary IHO

Turn off Intra-cell Handover?

Handover Case

Repeated Intra-cell Handover


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Handover Case

Unrealistic Handover


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Possible Reasons

Wrong locating settings, in Serving or Target cell

Note: Could be on purpose e.g. Dual Band network with HCS

Solution

Fix locating settings e.g. MSRXSUFF, BSRXSUFF

Unrealistic Handover

Reason & Solution


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Call Setup Failure

Input Activities, Initial TuningActivities

Initial Tuning

(Acceptance Test)

Troubleshooting

(Customer

complaint etc.)

Measurement Type

Large Area Drive Test

Short Call Sequences

Post-Processing Output

Statistics Report

Geographical Report

showing failure positions


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Call Setup Failure

Input Activities, TroubleshootingInput Activities

Initial Tuning

(Acceptance Test)

Troubleshooting

(Customer

complaint etc.)

Measurement TypeSmall Area Drive Test

Lock on problem cells BCCH

Force handover to the cell

Post-Processing OutputGeographical Report (if

necessary)


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Call Setup Failure Analysis

- Initial Tuning Scenario

Check the TEMS statistics report (Blocked Call)

if there is Call Setup Failure.

If yes, identify the problem cells and whichlogfile from geographical report.

Replay the logfile and jump to the Blocked Call

event.

Check if there is any successful call setup to the

problem cell.


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- Initial Tuning Scenario cont. Review the layer 3 messages to check at which

sequence the failure occur (random access,

SDCCH, TCH assignment etc.). Check STS report on the problem cell. Is there

any traffic (SDCCH & TCH) in the cell, SDCCH

& TCH seizures, congestion etc.

Check fault report & CDD configuration.


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C ll S F il A l i


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- Possible solutions

Low signal strength Signal strength analysis.

Interference Interference analysis.

High Congestion on SDCCH:

Define more SDCCHs.

Activate adaptive configuration of logical channel

feature and immediate assignment to TCH.

High Congestion on TCH:Add capacity/Tune coverage array.

Activate assignment to worse cell.


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Failed Call Setup (Blocked Call)

Example

Multiple Channel Requests.

Successful Random Access after the

third try.

Congestion in SDCCH.


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Dropped Call Case

- Input Statistics Report

Note from drive test.


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Dropped Call Case

- Analysis From plot, identify which & where in logfile

the dropped call occurs.

In the log file, Jump the drop call event. Check if there is a disrupt in the recording. If

yes could be a false drop due to TEMS

mobile disconnection during recording!!!

Dropped Call Case


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Dropped Call Case

- Analysis (cont)

Check the Radio environment just before drop:

If High Rxqual for a longer period of time and

RLINKT expire Interference problem.

If Low SS DL, SSDL < MSSENS ( -104dBm) lowsignal strength problem.

If TA > 63 too far from the cell.

If DL radio is good, check the TX power. If

there is MS power down regulation when theMS is close to the cell. If full power suspect

uplink interference or antenna, TMA problem.


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From TEMS Logfile

Good Signal strength DL, Good Rxqual DL

No call set up possible unless very close to site = high SS

Dropped call when SS < approx. -75dBm

Analysis

Since DL SS & Rxqual is good

Suspect UL problems e.g. external uplink interference

Conclusion

TMA power turned off

Miscellaneous Case 1


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From TEMS Logfile

TCH has lower Signal strength than BCCH (Own BCCH included in

BA-list)

BTS power control = OFF

Miscellaneous Case 2

CHG0BCCH

TCH

TCH

TCH

TCH

TCH

TCH

SDCCH\8

CHG1 TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

Configuration/cellSEKTOR A

SEKTOR B

SEKTOR C

Conclusion

Antenna cable for TCH is swapped between sectors (CDU-A)


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GPRS Measurement Activities GPRS Performance Prediction

GPRS Field Measurement


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GPRS Throughput Prediction Perform Throughput prediction for eachcoding scheme


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Cell Reselection Prediction Dedicated mode drivetest

HO types LA HO (10)

HO int. (220)

LA HO at BQ (1)

HO int. at BQ (11) BSC3 serving

Other BSC


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Cell Reselection Prediction BCCH Scanning Simulate the cell update with different CRH

valuesCRH = 4 dB CRH = 8 dB

CRH # HO

0 365

2 246

4 211

6 1788 156

10 147

12 138

14 130


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- ProcedureSet up files

Cell definitionsPreparations

TEMS,IP Sniffers

Dig maps

Excel

Mapinfo

Graphical

presentation of routeCharts / Tables

Report

?GIMS


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- Type of Measurements Application Performance Test

Ping

WWW FTP

WAP

Mobility Performance Investigation

Cell Reselection

RA Update



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- Application Performance Test

Attached performance

Attached Time = Attach Complete msg Attach

Request msg Attach Success Rate

PDP context activation performance

PDP context activation = Activate PDP Context

Accept msg Activate PDP context request

Throughput on RLC level

Dela


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- Mobility PerformanceInvestigation

Number of Cell Reselection & RA Update TCP Outage Time

Cell Reselection Failure


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Mobility test CRH = 4, CRO = 4


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Cell Reselection Sample Report

Routing Area Time Cell TargetCell

Reselectiontime

Result Comments

BSC1 16:30:42 D0241A D0241C 2 s OK NABSC1 16:33:18 D0241B D0242A 2 s OK NABSC1 16:35:04 D0242A D0248C 21 s OK This cell reselection was

made to a cell located quitefar away (not the closest),thus the RxLev was quite

bad!

BSC1 16:37:44 D0244B D0248C -- NA No throughput before orafter the cell reselection.

This is due to that the cellDF0242B were halted by

some reason!

BSC1 16:38:11 D0248C D0244B -- Failed The through put was neverresumed and the FTP

connection was aborted bythe ftp-server!

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Training_DriveTest & Optimization