CS CDR and CSSR of some NodeBs decrease withour any alarm - E\\\ Sys

[Interface]

Dear all,
Recently, Some NodeB in our Network decrease at CDR and CSSR KPIs with same phenomenon . The No of Drops increased at Other Reason in Peak hour. The CSSR decrease at both RRC SR and RAB SR and the CS CSSR is worse than Eul CSSR (96% compare to 98%). This NodeB didn't congest at all resource, no Alarm at Hw and Transmission. When we got the log trace at NodeB, we reveived the fault as below:_{[2012-05-02 07:03:25.492] bmrFaultServer bmr_fault.c:550 INFO:Received BP_RBCI_FAULT_IND(snid:20480,ft:0x10,ai:0x0,rc:0x5,li:0,es:"Unable to process EdchDecTask. : 0x00B6
") from DSP20480/dpp_main(0x00020534)
[2012-05-02 07:03:25.492] bmrFaultServer bmr_fault.c:552 INFO:Ignored RBCI_FAULT_IND (RBCI_NO_ACTION)
[2012-05-02 07:03:25.496] UlTch20480_UlTchJobSchedProcess /vobs/rbs/bb/dp/subsystems/DecProc/src/PreProcJob.cpp:142 ERROR:Unable to process EdchDecTask. : 0x00C7
[2012-05-02 07:03:25.532] bmrFaultServer bmr_fault.c:550 INFO:Received BP_RBCI_FAULT_IND(snid:20480,ft:0x10,ai:0x0,rc:0x5,li:0,es:"Unable to process EdchDecTask. : 0x00B7
") from DSP20480/dpp_main(0x00020534)
[2012-05-02 07:03:25.532] bmrFaultServer bmr_fault.c:552 INFO:Ignored RBCI_FAULT_IND (RBCI_NO_ACTION)
[2012-05-02 07:03:25.536] UlTch20480_UlTchJobSchedProcess /vobs/rbs/bb/dp/subsystems/DecProc/src/PreProcJob.cpp:142 ERROR:Unable to process EdchDecTask. : 0x00C8}
I don't know what's problems. Please hepl me!

[Interface]

Who can help me?

[Fado]

did you check core-MGW end? there might be a signalling issue,fluctuation at the core end..