7/27/2019 Determining Inter RAT Handover Target Cell

1/4

Determining Inter RAT HOTarget Cell

Internal

Author Richard S. Dayrit Huawei ID 84240

Office Dubai Product BSC6800

Date January 12, 2006 Version BSC6800V100R002C03B092

Determining Inter RAT HO Target Cell

Specification of the issue

From the RNC LMT Traceviewer we can see from the signaling messages

the GSM target cell during the Inter RAT Handover procedure. We can also

know how which GSM CELL and LAC it failed to Handover.

Alarm Information

Based on the KPI last January 2005 the values we are getting from

CS_INTRAT_HO_OUT_PREP_SUCC_RATE(%) is below 50%. Please see

the below table for reference.

Resulttime

CS_

INTRAT_

HO_

OUT_

PREP_SUCC

CS_

INTRAT_

HO_

OUT_PREP

C

S_

INTRAT_

HO_

OUT_

PREP_

SUCC

_RAT

E(%)

1/26/2005

1621 7460 21.73%

1/27/2005

1615 4128 39.12%

1/28/2005

1244 3562 34.92%

2008-08-29 Huawei Confidential Page 1 of 4

7/27/2019 Determining Inter RAT Handover Target Cell

2/4

Determining Inter RAT HOTarget Cell

Internal

Analysis

Figure 1

Under BSC6800 LMT go to the Maintenance Navigator Tab and run an IU interface

tracing. Select trace all DPCs. On the tracing message type, tick all messages with

RELOCATION on its filename.

1. On the BSC Traceviewer you will see signaling messages on the screen. For us to beable to see the target and source cell for the Inter RAT handover we need to select

the message RANAP_RELOCATION_REQUIRED. See Figure 1.

2. Double click the message and you will see another window. This window includes the

details for this message. Browse the window and look for the sourceID word. Below

this you will see pLMNidentity. See figure 2.

3. For the pLMNidentity you will know the MCC, & MNC. Read the value backwards.

(i.e. 24 f4 20 is read as 424(MCC) 02 (MNC)

4. You can also see the LAC and SAC. Please note that this is in Hexadecimal format.

(i.e. 9c 4b is equivalent to 40011). SAC is also read the same way. See figure 2.

2008-08-29 Huawei Confidential Page 2 of 4

7/27/2019 Determining Inter RAT Handover Target Cell

3/4

7/27/2019 Determining Inter RAT Handover Target Cell

4/4

Determining Inter RAT HOTarget Cell

Internal

Attachment

None.

Correlated information

This test case is correlated with Troubleshooting Inter RAT Handover

Preparation test case. During daily maintenance work for RAN we

encounter a problem on Inter RAT Handover Preparation. For this reason

we need to know the specific GSM cell ID and LAC information where the

handover preparation is failing.

2008-08-29 Huawei Confidential Page 4 of 4