The document provides suggestions to improve DCR (drop call rate) after a swap project. It discusses checking for hardware problems like alarms, VSWR, and resetting sites. It also recommends adjusting cell configuration parameters like power levels, send/receive modes, and neighbor relationships. Finally, it suggests configuring data parameters like coverage, interference, and handover settings by collecting measurements and adjusting values for thresholds, timeouts, and filters. Adjusting these hardware, configuration, and data parameters based on analysis of measurements can help reduce drop calls after a swap.

1. 文档名称 文档密级：
How to Improve Swap DCR
Background:in swap project,after swap there were some cells with worse dcr,in order
to improve this kpi,We summarized these aspects and gave some suggestions:
1 Hardware problem
1.1 check the alarm and history alarm,normally it can lead to call drops due to
Equipment Failure.
1.2 reset the site,If there are some call drops due to Equipment Failure without
alarm,maybe there are something wrong with our BTS software.reset the site with level 4
during night.if also not ok,get the help from BSC guy.
1.3 check the WSWR of the site through MML,if the value of VSWR is bigger than
1.5,maybe there are something wrong with feeder,TMA,or antenna and so on.let site
enginner go to this site with site master for testing the VSWR.
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2 CELL CONFIGURATION
2.1 Power configuration,For our swap project,we should keep the same power with
before.Our trx default power as below,we can adjust the power type,power level and
power finetune of trx to keep the same with alcatel’s TOC.
TRX TYPE Static TOC
GRFU 1TRX
80w/49dBm
GRFU 2TRX
40w/46dBm
GRFU 3TRX
27w/44.3dBm
GRFU 4TRX
20w/43dBm
GRFU 5TRX
12w/40.8dBm
GRFU 6TRX
10w/40dBm
DRFU 900
45W/46.5dBm
DRFU(PBT)
1800
63w/48dBm
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DRFU 1800
40W/46dBm
2.2 Send Receive Mode checking,for different trx configuration,there are different
values of send receive mode.according to the configuration as below,pls correct it.
TRX
CONFIGURATION
Send Receive Mode
1 GRFU Double Feeder(1TX+2RX)
2 GRFU Single Feeder(1TX+2RX)
1 DRFU Double Feeder(2TX+2RX)
2 DRFU (PBT) Single Feeder(1TX+2RX)
2.3 Neighbors Relationship,we can use Nastar to check the neighbors,especially missing
neighbors.
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2.4 Frequency HSN MAIO and so on.
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3 DATA CONFIGURATION
3.1 Coverage Parameters
About this kind problem,firstly we can collect the Measurement from M2000:
Number of MRs based on TA per TRX
Radio Link Failure Measurement per TRX
Radio Link Failure Measurement based on TA per TRX
Receive Quality Measurement per TRX
TCHF Receive Level Measurement per TRX
TCHH Receive Level Measurement per TRX
Uplink-and-Downlink Balance Measurement per TRX
After we anlyzed the report,we can know about the Receive Quality,Level,TA and so on.if
the TA is big for coverage plan,we should control the coverage.parameters we can adjust
as below:
a. RACH Min.Access Level(dbm),default value is -115,recommended value -109.
b. Random Access Error Threshold, default value is 180, recommended value 220
c. RXLEV_ACCESS_MIN, default value is 8, recommended value 10.
d. otherwise,we can adjust downtilt and power to control the coverage.
3.2 Interference Parameters
About this kind of problem,we can collect the Measurement from M2000:
Radio Link Failure Measurement per TRX
Receive Quality Measurement per TRX
TCHF Receive Level Measurement per TRX
TCHH Receive Level Measurement per TRX
GSM Cell to GSM Cell Outgoing Handover Measurement
Interference Band Measurement per TRX
After anlysis,if there are high receive level with bad quality,a lot of quality handovers and
interference band are bigger than 3,there maybe interference,we can adjusted the
parameters as below:
a. Radio Link Timeout(SACCH period (480ms)) this parameter is about downlink,
default value is 16, recommended value 52
b. SACCH Multi-Frames(SACCH period (480ms)) this parameter is about uplink, default
value is 18, recommended value 36.
c. T200 FACCH/F(5ms) default value is 50,recommended value 80.
d. T200 FACCH/H(5ms) default value is 50,recommended value 80.
e. N200 of FACCH/Half rate, default value is 29,recommended value 50.
f. N200 of FACCH/Full rate, default value is 34,recommended value 50.
g. if there is strong interference through monitoring channel interference band,we need
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eliminate it.
3.3 Handover Parameters
About this kind of problem,we can collect the Measurement from M2000:
Incoming Internal Inter-Cell Handover Measurement per Cell
Outgoing Internal Inter-Cell Handover Measurement per Cell
Incoming External Inter-Cell Handover Measurement per Cell
Outgoing External Inter-Cell Handover Measurement per Cell
GSM Cell to GSM Cell Outgoing Handover Measurement
After anlysis,if there is bad hsr between 2 neighbors,and also Cell Outgoing Handover Fail
Reconn Fail happens,we need adjust some handover parameters as below:
a. Edge HO UL RX_LEV Threshold,default value is 10,recommended value 15.
b. Edge HO DL RX_LEV Threshold,default value is 19,recommended value 25.
c. Min DL Power on HO Candidate Cell,default value is 10,recommended value 0.
d. Min UP Power on HO Candidate Cell,default value is 10,recommended value 0.
e. Min Interval for Consecutive HOs,default value is 4,recommended value 2.
f. Min Interval for Emerg.HOs,default value is 4,recommended value 2.
g. Filter Length for TCH Level,default value is 6,recommended value 3.
h. Filter Length for TCH Qual,default value is 6,recommended value 3.
i. DL Qual. Threshold,default value is 55,recommended value 40.
j. UL Qual. Threshold,default value is 55,recommended value 40.
k. MR.Preprocessing, default value is YES,recommended value NO.
About the values of parameters,just recommended,you can decide to choose according
to actual situation, detailed meaning of these parameters,you can get it from LMT help
document,thanks,
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7. 文档名称 文档密级：
eliminate it.
3.3 Handover Parameters
About this kind of problem,we can collect the Measurement from M2000:
Incoming Internal Inter-Cell Handover Measurement per Cell
Outgoing Internal Inter-Cell Handover Measurement per Cell
Incoming External Inter-Cell Handover Measurement per Cell
Outgoing External Inter-Cell Handover Measurement per Cell
GSM Cell to GSM Cell Outgoing Handover Measurement
After anlysis,if there is bad hsr between 2 neighbors,and also Cell Outgoing Handover Fail
Reconn Fail happens,we need adjust some handover parameters as below:
a. Edge HO UL RX_LEV Threshold,default value is 10,recommended value 15.
b. Edge HO DL RX_LEV Threshold,default value is 19,recommended value 25.
c. Min DL Power on HO Candidate Cell,default value is 10,recommended value 0.
d. Min UP Power on HO Candidate Cell,default value is 10,recommended value 0.
e. Min Interval for Consecutive HOs,default value is 4,recommended value 2.
f. Min Interval for Emerg.HOs,default value is 4,recommended value 2.
g. Filter Length for TCH Level,default value is 6,recommended value 3.
h. Filter Length for TCH Qual,default value is 6,recommended value 3.
i. DL Qual. Threshold,default value is 55,recommended value 40.
j. UL Qual. Threshold,default value is 55,recommended value 40.
k. MR.Preprocessing, default value is YES,recommended value NO.
About the values of parameters,just recommended,you can decide to choose according
to actual situation, detailed meaning of these parameters,you can get it from LMT help
document,thanks,
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