GSM FER ISSUE

[esahmat]

Hi,

i have found that we have a high FER in the network. In the urban area tems drivetest show :
- radio parameters (F -full; S-sub)
RxLev -47 F , -44 S
Rx Qual 9.05 F, 0.14
FER 25 F, 0 S
BER actual 0 F
FER actual 0 F
SQI 30
C/I worst 23.7 F, 23.7 S
MS Power control level 12
DTX 29
TA 0
RL timeout counter (cur) 20
RL timeout counter (max)20
MS Behaviour Modified

Codec used is AMR Full rate. RAN is NSN full flexi BTS. These FER values have very fast repetition pattern.

Help appreciated.

[kevin_h811]

hi ehsamat,

Is your network DTX enabled (Discontinuous Transmission) cause you are presenting 2 variables, Full and Sub. Is your site/network Rf Hopping or not?does it have a single GSM antenna or with Rcv Diversity? Can u pls add more details.

Regards//

[esahmat]

Kevin,

yes the network is DTX enabled, synthesized hopping is used on some sites - listed measurements are from non hopping cell.
the use of multiband VET antenna is common (G900, 1800/2100) - same e-DT on both, rx div enabled.

test call is established to announcement box (constantly replaying a short clip). xi have tested also the competitors network and saw same FER pattern. Is it possible that this is due to end of announcement?

Thx

[kevin_h811]

hi EHSAMAT,

I have somelog files with FER issue due to OVERSHOOTING of sites, but after antenna adjustment, FER improved.
Have u observed your serving cells if they are overshooting?

Regards\\