3g handover to gsm prepare handover successful rat

Document Title For internal use only

2007-05-28 Huawei Proprietary No Spreading without Permission Page 1 of 2

Author Wen guangcong ID 39411

Region/Office UMTS RNP Product WCDMA RNP

Application Date 2007-05-28 Version V100R006

Assessor

Document Title： 3G CS handover to GSM prepare handover successful rate is low

Symptom

Description：

From the traffic statistics we found the 3G CS handover to GSM prepare

handover successful rate is low, about 12%.

Warning

Message：

NO

Cause Analysis： In the MSC configure data LAI is wrong.

Process： 1, check neighbor data from 3G handover to GSM in RNC, checks

each NGSM cell information, this is normal.

2, trace singling in RNC and found many prepare handover failed, the

reason is “unknown target RNC”.

3, according to step 2 we known some place configure incorrect in

MSC, check MSC data and find LAI is wrong.( LAC information not

correct)

4, changed MSC LAI (LAC) information same to RNC, the prepare

successful rate is about 86%.

Suggestion and

summary：

3G handover to GSM problem should check RNC and MSC configure

data. Especially MSC, it’s easy to forget.

Attachment：

Document Title For internal use only

2007-05-28 Huawei Proprietary No Spreading without Permission Page 2 of 2

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