SR5251060 Root Cause Analysis for RRC Setup Success Rate Degradation

SR5251060 Root Cause Analysis for RRC Setup Success Rate degradation Issue

011

Date

2010-07-0219

HUAWEI TECHNOLOGIES CO., LTD.

Issue 01 (2015-10-19)

Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd

1

Copyright © Huawei Technologies Co., Ltd. 2010. All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means without prior written consent of Huawei Technologies Co., Ltd.

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Web site:

http://www.huawei.com

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Issue 01 (2015-10-19)


3

SR5251060 Root Cause Analysis for RRC Setup Success Rate degradation

Contents

About This Document Trouble Ticket Information Trouble Ticket Number

5251060

Prepared by

Huanghui 00206795

Approved by Approval Date

2015-10-19

Revision History Issue

Date

Author

Change Description

01

2015-10-19

Huanghui 00206795

First Version


Contents

1

Contents

About This Document......................................................................iii 1 Basic Information.......................................................................1-1 2 Problem Description...................................................................2-1 3 Problem Analysis.......................................................................3-1 3.1 The Degradation of RRC Setup SR is mainly caused by L.RRC.SetupFail.NoReply...................................3-1 3.2 TOP UE Cause the RRC Setup Success Rate degradation in the Site LTE_Dobsonville_GSMT01_SGS....3-2 3.2.1 Analysis at 2015/10/14 05:00................................................................................................................3-3 3.2.2 Analysis at 2015/10/14 06:00................................................................................................................3-4 3.3 TOP UE Cause the RRC Setup Success Rate degradation in the Site LTE_Nupen_Rd_GSMT01_SGS......3-5 3.3.1 Analysis at 2015/10/13 01:00................................................................................................................3-5 3.3.2 Analysis at 2015/10/13 02:00................................................................................................................3-6

4 Root Cause................................................................................4-1 5 Corrective Action.......................................................................5-1 5.1 Workaround....................................................................................................................................................5-1 5.2 Solution...........................................................................................................................................................5-1

6 Preventive Action....................................................................... 6-1


2

6 Preventive Action

Basic Information

Product Name

Version

BTS3900

V100R009C00SPC230

Issue 01 (2015-10-19)


1

3

Problem Description

Customer complained that two eNodeBs’ RRC Setup Success Rate degraded, as shown in Fig 2-1 and Fig 22.Huawei need to explain the degradation.

Figure 2-1 RRC Setup SR of LTE_Dobsonville_GSMT01_SGS

Figure 2-2 RRC Setup SR of LTE_Nupen_Rd_GSMT01_SGS

4

Problem Analysis

The Degradation of RRC Setup SR is mainly caused by L.RRC.SetupFail.NoReply. 4.1

From counters, RRC Setup Fail is mainly caused by L.RRC.SetupFail.NoReply, as shown Fig 3-1 and Fig 32.

Figure 3-1 RRC Setup Fail detail reason of LTE_Dobsonville_GSMT01_SGS

Figure 3-2 RRC Setup Fail detail reason of LTE_Nupen_Rd_GSMT01_SGS

L.RRC.SetupFail.NoReply Measurement Points as below:

TOP UE Cause the RRC Setup Success Rate degradation in the Site LTE_Dobsonville_GSMT01_SGS 4.2

Analysis main board log at 05:00 and 06:00 2015-10-14 for example, L.RRC.SetupFail.NoReply occured 126 and 189 on cell3.

Figure 3-3 L.RRC.SetupFail.NoReply of site LTE_Dobsonville_GSMT01_SGS

4.2.1 Analysis at 2015/10/14 05:00 Check CHR log of this time slot, also 126 records, and except first record, others have regularity, that is every 5 times is a cycle, each message interval 11~12s.

Figure 3-4 CHR log of site LTE_Dobsonville_GSMT01_SGS

4.2.2 Analysis at 2015/10/14 06:00 Check CHR log of this time slot, also 189 records, and except UE not sent 1 time , others have regularity, that is every 5 times is a cycle, each message interval 11~12s.

Figure 3-5 CHR log of site LTE_Dobsonville_GSMT01_SGS

TOP UE Cause the RRC Setup Success Rate degradation in the Site LTE_Nupen_Rd_GSMT01_SGS 4.3

Analysis main board log at 01:00 and 02:00 2015-10-13 for example, L.RRC.SetupFail.NoReply occured 20 and 21 times on site.

Figure 3-6 L.RRC.SetupFail.NoReply of site LTE_Nupen_Rd_GSMT01_SGS

4.3.1 Analysis at 2015/10/13 01:00 Check CHR log of this time slot, also 20 records, all records have regularity, that is every 5 times is a cycle, each message interval around 22s.

Figure 3-7 CHR log of site LTE_Nupen_Rd_GSMT01_SGS

4.3.2 Analysis at 2015/10/13 02:00 Check CHR log of this time slot, also 21 records, all records have regularity, that is every 5 times is a cycle, each message interval around 22s.

Figure 3-8 CHR log of site LTE_Nupen_Rd_GSMT01_SGS

5

Root Cause

RRC Setup Fail cause by UE No Reply, which cause by TOP users in live network.

6 6.1

Workaround

NA

6.2 NA.

Solution

Corrective Action

7 NA

Preventive Action

SR5251060 Root Cause Analysis for RRC Setup Success Rate Degradation

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