Gsm bss network kpi (sdcch congestion Rate) Optimization Manual

GSM BSS Network KPI (SDCCH Congestion Rate) Optimization Manual

INTERNAL

BOM Code		Product Name	GSM BSC
Confidentiality Level	INTERNAL	Product Version	V1.1
Compiling Department		Document Version	Total 31 pages

GSM BSS Network KPI (SDCCH Congestion Rate) Optimization Manual

(For internal use only)

Prepared by	GSM&UMTS Network Performance Research Department Yang Chunjie	Date	2008-05-19
Reviewed by		Date
Reviewed by		Date
>Approved by		Date

Huawei Technologies Co., Ltd.

All rights reserved
Revision Record

Date	Revision Version	Description	Author
2008-05-19	V1.0	Draft completed	Yang Chunjie 00119951
2008-06-02	V1.0	Adjust the sequence of problem location and add some suggestions of adjusting the related parameters affecting SDCCH congestion rate according to the advices of the experts in our team and the experts of network optimization and planning.	Yang Chunjie 00119951

References

Number	Reference	Author	Date
1	Guide to Optimization of SDCCH Congestion Rate	Wang Weiji, Yang Haiquan	2006-12-20
2	Baseline Specification of GSM BSS Network KPI (SDCCH Congestion Rate)	Wu Zhen	2007-04-09

Contents

1 Principles of SDCCH Congestion Rate 5
1.1 Definition 5
1.2 SDCCH Seizure 6
1.3 Signaling Procedure and Measurement Points 6
2 Factors of SDCCH Congestion Rate in GSM 6
2.1 Congestion Caused by Faults on Equipment or Transmission 6
2.2 Congestion Caused by Insufficient Signaling Resources 7
2.3 Congestion Caused by Improper Data Configuration 7
2.4 Congestion Caused by Interference 7
3 Optimazation Method of SDCCH Congestion 7
3.1 Analysis Procedure of SDCCH Congestion Rate 7
3.2 Optimazation Method of SDCCH Congestion Rate 9
3.2.1 Checking Hardware 9
3.2.2 Checking Channel Configuration 9
3.2.3 Checking Data Configuration 11
3.2.4 Checking the Um Interface 12
4 Test Method 13
5 Case Analysis of SDCCH Congestion Rate 13
5.1 Congestion Caused by Improper Configuration of Power 13
5.2 SDCCH Congesiton Caused by Improper Configuration of LAC 14
6 Feedbacks on High SDCCH Congestion Rate 15
Appendix Relevant Traffic Counters to BSC6000 SDCCH Congestion Rate 15

SDCCH Congestion Rate Optimization Manual
Keywords: SDCCH Congestion Rate
Abstract: This document introduces the definition and optimization method of SDCCH congestion rate.
Abbreviations:

Abbreviation	Full Spelling
SDCCH	Stand-alone Dedicated Control Channel

1Principles of SDCCH Congestion Rate

SDCCH congestion rate is one of the important counters that indicate accessibility in circuit service. This counter provides the ratio of failed SDCCH seizures due to busy SDCCH to the total requests for the SDCCH. SDCCH congestion rate indicates the failed requests for the SDCCH for various reasons. SDCCH congestion rate also indicates the status of the SDCCH resource utilization.

1.1Definition

The Huawei definition and formula of SDCCH congestion rate are as follows:

• 
  Definition:
  

Ratio of failed SDCCH seizures due to busy SDCCH to the total requests for the SDCCH

• 
  Formula:
  

SDCCH congestion rate = Failed SDCCH seizures due to busy SDCCH/Total requests for the SDCCH x 100%
Failed SDCCH Seizures due to Busy SDCCH = [Failed Immediate Assignment due to Busy Channels or Failed Configurations (SDCCH)] + [Failed Internal Inter-cell Handovers (No Channel Available) (SDCCH)] + [Failed Incoming Internal Inter-cell Handovers (No Channel Available) (SDCCH)] + [Failed Incoming External Handovers (No Channel Available) (SDCCH)]

1.2SDCCH Seizure

The requests for the SDCCH in GSM are mainly made in the following two procedures:

1. 
   The procedure for requesting the SDCCH for services such as point-to-point calls, location updating (only SDCCH), call re-establishment, or short messages;
   
2. 
   he procedure of SDCCH handovers (including both the intra-BSC and inter-BSC handovers)