Thanks for your response.
Here’s my reply on your question:
1) on cell 1, all your TREs are carrying a SDCCH timeslot ? That is surprising ! If there is no SDCCH ts defined on a TRX, you can’t observe SDCCH drop on this TRX.
=Yes, all TREs on Cell 1 have configured SDCCH TS.
2) Are those standard “static” SDCCH ts or dynamic SDCCH ts ?
= The configured SD TS are all static. We have dynamic ts too but we have a recovery time for this, TCH min recovery time for SDCCH to revert back to TCH channel.
3) What about the tch mean duration on each TRX of cell 1 ? Do you see traffic on those TRX 2, 3 and 4 ? TCH DROP RATE is OK ?
= Regarding the TCH DROP on TRE 2, 3, and 4. All is Ok but if you check on the immediate assignment success, it was quite low because of the high sd drop rate for the said TREs.
My solution to that problem was to swapped all SD Channel TS to TCH channel TS (for all TREs except the MBCCH TRE). Then I put the 3 SD Channels to MBCCH TRX and swapped the TCH TRE. Then after one day, I checked the stats and the SD Drop
rate of Cell 1 improved.
My concern was how come the other TREs did not produce good SDCCH drop rate. What could be the possible problem? is it the TREs but if i checked the board no alarms/faults seen.