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Main Tools for Radio Network Optimization GSM
Statistic 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)
Radio Network Growth Flow
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 TEMS INVESTIGATION fit in
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
Initial Tuning
• Produce Coverage Plot
• Identify Coverage Holes
• Identify Interference Area
• Optimize Neighbor Relations
• Find Hardware/Installation Problems
• Verify Parameter Setting
DESIGN & ROLLOUT PHASE
GPRS Performance Verification
DESIGN & ROLLOUT PHASE
• Application Performance Test
• WWW, FTP, WAP etc.
• Mobility Test
• Cell Reselection, RA Update
Traditional Optimization
• Investigate & Trouble-shooting Specific Areas
• Neighbor Relation Optimization
• Coverage Issues
OPERATION & IMPROVEMENT PHASE
Network Feature Optimization
Parameter Settings:
• MS, BTS Power Control
• HCS
• Idle Mode Behavior
• Locating Algorithm
• Frequency Hopping
• Intra-cell Handover
OPERATION & IMPROVEMENT PHASE
Verification of Network Changes
Did a certain change in the network give desired results?
• If can not identify the problem, perform drive test.
• During measurement, lock the BCCH of the problem cell.
• Review the layer 3 messages to check at which sequence the failure occur (random access, SDCCH, TCH assignment etc.).
Call Setup Failure Analysis- Possible reasons with ranking
• Low Signal Strength
• Interference
• High Congestion on SDCCH
• High Congestion on TCH
• Transmission Fault
• Faulty TRU/Hardware
• Central Processor Overload
• Software File Congestion
• Cell is not defined in MSC.
Call Setup Failure Analysis- 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.
Failed Call Setup (Blocked Call) Example
Multiple Channel Requests.
Successful Random Access after the third try.
Congestion in SDCCH.
Dropped Call Case- Input
• Statistics Report
• Note from drive test.
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- 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) low
signal 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 the MS is close to the cell. If full power suspect uplink interference or antenna, TMA problem.
• Verify or isolate the problem using STS (Drop call and reasons).
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
From TEMS Logfile
• TCH has lower Signal strength than BCCH (Own BCCH included in BA-list)
• BTS power control = OFF
Miscellaneous Case 2
CHG0
BC
CH
TC
H
TC
H
TC
H
TC
H
TC
H
TC
H
SD
CC
H\8
CHG1 TC
H
TC
H
TC
H
TC
H
TC
H
TC
H
TC
H
TC
H
Configuration/cellSEKTOR A
SEKTOR B
SEKTOR C
Conclusion
Antenna cable for TCH is swapped between sectors (CDU-A)
From TEMS Logfile
• Fail to perform Call Setup
Analysis
• Check if any success call setup to the same cell No
• Check if handover is possible Yes
• Suspected wrong cell definition in MSC but Cell is properly defined in MCS and LA