RACH Rejection Problem

[juanpico]

Hi Experts

Can someone help me with this?
A certain cluster of site is experiencing RACH Rejection <Huawei GSM Site>. Isolation of problem by troubleshooting has been done and several steps are already been tried as follows:

XPU expansion & Balancing <meaning this is not the only reason of problem>
CHREQCSMAXMSGNUMINPERIO modification from 100 to 200
LAPD Upgrade

The rest of the sites are already OK except of one site.
Holiday is coming, the only solution left is to limit the traffic by lowering the power or introducing a new site <which is not practical?> Extended BCH implementation <is this possible with Huawei>
Can someone help to know the cause of RACH rejection

Balbaleg ed Salamat,

juan

[kevin_h811]

Hi JUAN,

Have you checked your CFGMML if parameters related to RACH are all in default, why don't you compare them first with other NodeBs that are OK.
Use DUMP2CFGMML converter which you can find here in this forum.

Regards//

[jayk]

Extended Cell Implementations is possible in Huawei.

There are many counters to analyse the reason of RACH Rejections.
UL Intf in cell can cause Channel request not decoded properly and Request can be rejected.
Channel Request can be Phantom or Ghost RACH if your sites or on PLMN border with another network using same set of BCCH frequencies.
Non compatible UE sending Channel Request again and again.
No AGCH available for assignments.

Further analysis can be done by analyzing many other counters..

Add repo if find useful

[juanpico]

Hi JUAN,

Have you checked your CFGMML if parameters related to RACH are all in default, why don't you compare them first with other NodeBs that are OK.
Use DUMP2CFGMML converter which you can find here in this forum.

Regards//

Done with comparison, found out the general parameters related to RACH are in default.