05) Radio Network Optimization

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Transcript of 05) Radio Network Optimization

PowerPoint Concept of optimization
To work out various network problems after the the network put into service through different technical method to keep the system running in a good state.
Adjust different type of parameters
MSS parameters
The following cases need to optimize the network
After the network was put into service or just finish expansion
The quality decrease greatly or too much customer complaints
When subscribers changed and affect the network quality significantly
Unexpected events decrease the network quality
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Focus on
Cell physical para: Height, Downtilt, Azimuth
Frequency plan adjustment: Frequency reuse mode, BCCH\TCH carrier frequency
Others: Propagation model,output power of BTS
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Performance data and traffic from OMC-R
Driving test data
Feedback from the subscribers
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Driving test
Frequency scanning test: checking external interference ;
CW test: propagation model correction test;
Cell reselection border test;
Cell handover border test;
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A_Interface Data
The information of location update
The information of call drop
The traffic
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A-bis data
The whole signal procedure
The uplink signal between MS and Network
From the analysis of measure reportthe distributing information of RXLEVquality and number of measure report TA distributing informationthe information of balance between uplink and downlink
All of the signal information between BTS and BSC
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The antenna type
Path Loss
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BTS Output Power
Between the Directional antennas Outside of Horizontal 3dB Beam width
The tilt of Omni_Antenna
The height of antenna
The antenna typeFor example :the gain is too small
The Path Loss is big Landform or forest
The Mistake mount of antenna
WHY No signal
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PhenomenonThe coverage area of one cell is divided into two or more parts.
ReasonThe coverage is overshooting.
Result bring call drops if the some neighbor relations are not defined. frequent handover The congestion because of the big coverageThe island area often have interferences
SolutionReduce the coverage,adjust the down tilt of the cell etc.
CELL A
CELL B
Lonely Island
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Coverage Overlap
Some area covered by two or more cells is needed The area can provide coverage area continuously and handover well
The Overlap Area is Suitable for 20%~30% to the whole coverage area. If the overlap coverage area is big, the error handovers and call drops appear possibly.
Solution
Adjust the Radio parametersplan coverage area for each cell carefully .Just like adjust the down tilt of antenna and output power of BTS
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Reduce the coverage area of the main cell
Good frequency Plan.
Adjust the height of antenna
DPC,FH,DTX
ObjectIncrease the signal of main service cell ,reduce the signal strength of interference
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Down tilt
Unsuitable big direct down tilt can bring big problems through the alternant coverage.
We suggest that we use direct and electro-down tilt together if the down tilt is too much.
Down tilt too much
The problems solved by Frequency optimization
The regular BCCH Reuse :at least 4*3 better 5*3.
The continuous frequency used by BCCH only.
BCCH not frequency hopping.
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TCH Congestion
Reduce the coverage Area
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SDCCH Congestion
Alone cell
High traffic
The solution to solve SDCCH congestion
LAC
At MOST :32
Enough is OK ,At first,you can define many ,and reduce some
If some adjacent cell is left, maybe cause the handover success rate is low,and if the adjacent cell is important, call drop increase
The neighbor relation
RLT timer