hi Pix , Thanks for Answer…
a hardware failure on the TRX that carries one of the SDCCH –> That is right , i have changed SDCCH to another TS..
Let me why i ask this question :
you may contribute the problem more.
one of our network is 2G NSN network & we face 7745 CHANNEL FAILURE RATE ABOVE DEFINED THRESHOLD too much , 10 times or more daily ,
NSN support contract has been expired for us so i investigate this alarm on internet to find out a solution.
Accourding to Alarm if SDCCH Channel failure is more that %80 percent during 60 munites , network generates this alarm.
finally i observed that SDDCH drop rate high cells generate this alarm,
SDCCH drop rate is high because due to radio failure + due to Abis Failure , Other reasons are approximately zero effect when i check the SDDCH Report ( example : due to A failure, Due to Handover Faiure, illegal est. cause. LAPD failue, Network config. change, BSCU restart…etc no affect on SDDCH drop ) ..
So Due to Abis Failue is major impact on SDCCH drop in my network.
i have focused on Sdcch_abis_fail_call then…
Major impact on sdcch_abis_call is T3101 timer expiry,
some reasons why T3101 expries are Ghost access & Timing advance
interference level & Ghost Access a few through the network.
but i am going to check Timing advance level in sectors today.
My question what should i do more , what do you advise me to do ?
Thanks and best