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Reply To: The SDCCH assignment fail from the LU.


Dear Pix,
SDCCH assignment failure is about 10-15% SDCCH assignment failure = (MC149/(MC148+MC04)) but MC04(SDCCh bloking_congestion)=0).
We use only terrestrial Abis and Aters.
For the one typical bad cell (21.03.08 – from RNO):
1) SDCCH Drop Rate = 0% (MC138+MC137+MC07)=0;
2) TCH Assignment Fail=0% and TCH Successful Rate = 99% (MC703/MC718);
3)TCH Drop Rate = 1.4%;
4)SDCCH traffic BH per TRX = 0.17 Erl (SDC only on BCCH-tre);
5) TCH traffic BH per TRX = 2.95(tch-tre)+ 0.72 (bcch-tre);
– RXLEV DL AVG= – 77.61 dBm
– RXLEV UL AVG= – 81.22 dBm
– Path Balance Avg=17.65
– Timing Advance Avg=4..8
About MC149 – for the mentioned cell this value is about 50-60 failures per hour. T3101= 3 sec (maybe we have to change this period (make it longer?)
The value of Path balance is really high and it’s very strange, especially because we use TMA for 1800 cell !!!
I know that there was a Fault report in Alcatel “FR A45/131698” (MS Path Balance values are incorrect for DCS 1800 cells) but it had to be corrected in B8 (we use BSS B9 MR6).
Thanks a lot for your assistance!!