how to decrease RRC and RAB fail due to NoReply

[indrarui_costa]

Dear Expert 3G,

i have problem on 3G huawei network,
bad accessibility cause more RRC and RAB fail due to NoReply (coverage problem).
can you help me to give some solution ?

Many thanks ,

[The_Rf]

well, you should try to improve the Uu interface, this mean, improve the coverage
maybe you can start checking the TP distribution to check from the office how is the coverage and the interference of the sites, but the best option should be Drive Test

[oswe]

Dear Expert 3G,

i have problem on 3G huawei network,
bad accessibility cause more RRC and RAB fail due to NoReply (coverage problem).
can you help me to give some solution ?

Many thanks ,

did you check Rach delays ? it is helpful to know if the people is close to your antenna or not.

[lamagica]

You should check your SPU overload, and do some rehoming some sites with big traffic to balance / reduce the board load..

[indrarui_costa]

well, you should try to improve the Uu interface, this mean, improve the coverage
maybe you can start checking the TP distribution to check from the office how is the coverage and the interference of the sites, but the best option should be Drive Test

Can we adjust some parameter to reduce it ? and what parameter can be do it?

many thanks,:D

[pongpang]

- check distance of user by TP,, adj tilt
- check RTWP
- try to increase parameter T381

[The_Rf]

Can we adjust some parameter to reduce it ? and what parameter can be do it?

many thanks,:D

first need to check if is coverage, maybe the DL coverage is OK but there is so many noise in the uplink
if need more downlink coverage maybe can add power to the DL channels (pcpich), this can improve the coverage on some cells but if is not enough carefull also will put more Ec/Io in the air, so be carefull
if the RTWP is high (uplink coverage), this is more complicated to reduce, maybe check the propagation of the cells and try to reduce the coverage, the best option to be clear is to do a drive test, but is expensive, other option is to check the TP (or PD dont remember the right name) that is the same thath RACH delay that oswe propossed

BR

[daohuyhp]

- check distance of user by TP,, adj tilt
- check RTWP
- try to increase parameter T381

What value of T381 we should use, the default value is 600ms.

[pongpang]

What value of T381 we should use, the default value is 600ms.
the first, try to set to D800 (800ms)

[daohuyhp]

the first, try to set to D800 (800ms)

Is there any parameters at cell level can help us fix this problem?
I don't want to change RNC parameters because the RNC KPI is good.

[pongpang]

Is there any parameters at cell level can help us fix this problem?
I don't want to change RNC parameters because the RNC KPI is good.

Its will be improve CSSR also,,
or can try to downtilt

[cococrunch]

Check worst cells if FACH utilization high and add another SCPCCH. This could be due to FACH congestion since RRC connection request uses FACH channel.