Inter-Rat handover(3G to 2G) failure due to 2G parameter mistake

Case Name：

Inter-Rat handover(3G to 2G) failure due to 2G parameter mistake

Description： CS handover from 3G to 2G can not happen

Product Version：

RNC: V900R012ENGC01SPC200

NodeB: V200R012C00SPC220

Alarm： NULL

Reason

Analyze：

2.1 RNC 2G external cell definition and 2G cell in BSC dump comprasion checking

The cell parameters such as BCCH/BSCI/LAC…are all the same.And all the switch

regarding inter-rat hanover in RNC are enabled in RNC.

2.2 DT log and CDT anlysis

From the DT log, we find that the UE can go to CM triggered by 2D event,and also receive the

MC including 2G neighbours. the UE send MR to RNC periodically,but no HO cmd from RNC

From UE Trace in RNC,we find RNC has already received the MR from UE.and send

reolacation required to CN,but CN reject.

And the Reason of rejection is om-intervention.

Conclusion： Then we check the 2G cell data configuration in MSC.Informed by NSS team,the 2G and 3G

share the same MSC,no need to add 2G cell in the MSC again.The data configuaration in MSC

is OK.We check the parameters in BSC regarding the handover.We found that one parameter is

not configed correctly(Inter-RAT In BSC handover is not enabled) .

Attachment： Null.