- This topic has 5 replies, 1 voice, and was last updated 8 years, 8 months ago by pix.
15th May 2012 at 07:55 #68225SomalilandGuest
In our 2G BSS network,
one of our BTS has bad voice quality, unidirectional voice calls and all kinds of noise is present in every call.
problem started with HUAWEI BTS312 1800MHz S4/4/4, after troubleshooting each TRX we found a faulty TRX and we replaced with a new one, problem continued,
we degraded the BTS to S3/3/3,
still the problem is there.
recently, we replaced the whole BTS with new DBS3900 S2/2/2 1800MHz, using the old antenna sectors,
Drive test shows that RXlev, RXQual and also C/I are good.
problem area is same to both near and far field.
what do you think the problem?
regards,15th May 2012 at 10:13 #68226pixGuest
hi, it’s probably a transcoding issue (TC), or an A interface (BSC-MGW or BSC-MSC) problem.
Ensure that those interfaces are not wrongly mapped from one end to the other.
Ensure the TC does not show any alarm.16th May 2012 at 08:15 #68227AfroGuest
i think the problem is the antennas and the cabling,
please check VSWR and UL & DL quality,
how is it possible the problem to be TC when only one BTS has bad voice quality, i think the A interface is not the problem.
also check the ABIS interface and the E1.17th May 2012 at 10:22 #68228somalilandGuest
i heve checked the TC and all the E1s of A interface, i changed the E1 port of the Abis for the BTS and the problem is still there, please can any one help me to rectify this problem17th May 2012 at 10:58 #68229eng. BiqindheGuest
pls give reply………..
thanks17th May 2012 at 17:01 #68230pixGuest
afro – you’re right, i answered a little quick.
focusing on a BTS issue makes more sense.
the problem is happening on all the cells of the BTS ?
are you able to see the impacts on KPIs such as call drops, tch assignments failures, sdcch drops, sdcch assignments failures ?
have you checked the path balance ?
please do so on each TRX if possible.
A good investigation method is to lock all trx and unlock only one at a time, in order to perform call test.
if there is a mixed feeders, the TX of some TRX might be transmitted to the antenna of the other sector, etc… that might cause very poor call quality when the call is assigned on those TRX.