CDMA2000 Handbook for Onsite Optimization-20071021-B-1.0

Handbook for Onsite Optimization of CIS CDMA

Huawei Technologies Co., Ltd

All Rights Reserved

Revision Record

Date Revision version

Descriptions Author

2004-08-04 1.00 First draft completed CIS RNP Dept.

2007-10-21 1.01 Reviewed and modified the contents in

red Fu Yingshi

Table of Contents

Chapter 1 Overview.......................................................................................................................... 8

Chapter 2 Common Settings of Mobile Phones ............................................................................ 9 2.1 Basic Principles of Setting and Using Mobile Phones.......................................................... 9 2.2 H100 Mobile Phone Password ........................................................................................... 10 2.3 Basic Settings of Programming Mode of H100 Mobile Phone ........................................... 10 2.4 Use of Test Modes of H100 Mobile Phone......................................................................... 12

2.4.1 Enter the Debug Interface ........................................................................................ 12 2.4.2 Markov Call .............................................................................................................. 12

2.5 Settings of Data Service of Mobile Phone .......................................................................... 12 2.5.1 Modem Installation ................................................................................................... 12 2.5.2 Establishment of New Connection ........................................................................... 13 2.5.3 Settings of Mobile Phone ......................................................................................... 13

Chapter 3 Use of Panorama .......................................................................................................... 14 3.1 Software Installation and Description ................................................................................. 14 3.2 Methods of Use................................................................................................................... 14

3.2.1 Creating Project........................................................................................................ 14 3.2.2 Base Station Import.................................................................................................. 15 3.2.3 Equipment Configuration.......................................................................................... 15 3.2.4 Start Drive Test ........................................................................................................ 15 3.2.5 Introduction to Main Windows.................................................................................. 16 3.2.6 Data Playback .......................................................................................................... 18 3.2.7 Data Statistics .......................................................................................................... 18

3.3 Summary of Experience ..................................................................................................... 19 3.3.1 Equipment Connection............................................................................................. 19 3.3.2 Some Experience in Evaluating Network Indices .................................................... 20

Chapter 4 Common Commands for Modification of Network Optimization Parameters ........ 21 4.1 Maintenance Console Version and Description.................................................................. 21 4.2 Basic Commands for Information Query ............................................................................ 21

4.2.1 BSC Information Query ............................................................................................ 21 4.2.2 BTS Information Query ............................................................................................ 21 4.2.3 CELL Information Query .......................................................................................... 21

4.3 Power Parameter Commands ............................................................................................ 22 4.3.1 Description and Precautions .................................................................................... 22 4.3.2 Pilot Channel ............................................................................................................ 22 4.3.3 Synchronization Channel ......................................................................................... 23 4.3.4 Paging Channel........................................................................................................ 23 4.3.5 Fast Forward Power Control .................................................................................... 23

4.4 Commands for Neighbor List Parameters .......................................................................... 23 4.4.1 Description and Precautions .................................................................................... 23 4.4.2 Query of Neighbor List Relation ............................................................................... 24 4.4.3 Addition of Neighbor List .......................................................................................... 24 4.4.4 Deletion of Neighbor List.......................................................................................... 24 4.4.5 Modification of Neighbor List Priority ....................................................................... 25

4.5 Handoff Parameter Commands .......................................................................................... 25 4.6 Access Parameter Commands ........................................................................................... 25 4.7 Summary of Experience ..................................................................................................... 25

Chapter 5 Common Commands for Maintenance and Information Tracing ............................ 26 5.1 Common Maintenance Commands .................................................................................... 26

5.1.1 Query of Equipment Version .................................................................................... 26 5.1.2 Query of Resource Status of Sector Carrier: ........................................................... 26 5.1.3 Query of BTS Site Name and O&M IP..................................................................... 26 5.1.4 Query of Information about PN, SID, NID, and LAC: ............................................... 27 5.1.5 Query of E1 Link Status: .......................................................................................... 27 5.1.6 Query of Longitude/Latitude, Sea Level Elevation, and Number of Locked Satellites of a Base Station: .............................................................................................. 27 5.1.7 Query of Realtime Forward Power Load of Sector Carrier; Occupation of Channels, CEs, and WALSH Code Channels; Channel Handover.................................................... 27 5.1.8 Carrier Blocking:....................................................................................................... 28 5.1.9 Carrier Unblocking: .................................................................................................. 28 5.1.10 Start RSSI Automatic Realtime Tracing:................................................................ 28

5.2 Signaling Tracing ................................................................................................................ 28 5.2.1 CBSC Operation Maintenance Console .................................................................. 28 5.2.2 CBSC Test Desk ...................................................................................................... 29

5.3 Realtime Tracing of Base Station ....................................................................................... 32 5.3.1 Tracing of Transmitter Power:.................................................................................. 32 5.3.2 RSSI Tracing: ........................................................................................................... 32 5.3.3 FER Tracing: ............................................................................................................ 32

Chapter 6 Common Used Methods for Data Service Optimization ........................................... 33 6.1 Description .......................................................................................................................... 33 6.2 Optimization of Goal FER of Data Service ......................................................................... 33 6.3 Optimization of Network Load Threshold ........................................................................... 34 6.4 Optimization of Time Parameters for Allocating Data Traffic channel................................ 34 6.5 Optimization of Threshold for Pilot Strength Allocation ...................................................... 34 6.6 Optimization of SCH Continuation in Data Service ............................................................ 35 6.7 Description of Data Service Test Performance .................................................................. 36

Chapter 7 Common Used Methods for Traffic Statistics Analysis............................................ 38 7.1 Implementation of Traffic Statistics..................................................................................... 38 7.2 Common Operations of Traffic Statistics ............................................................................ 38 7.3 Common Indices for Traffic Statistics ................................................................................. 38

7.4 Method of Traffic Statistics Analysis................................................................................... 39 7.5 Analysis of Main Indices ..................................................................................................... 40

7.5.1 Success Rate of CS Call Establishment .................................................................. 40 7.5.2 Call Drop Rate of Wireless System.......................................................................... 40 7.5.3 Soft Handoff Performance........................................................................................ 42 7.5.4 Traffic channel Congestion Rate.............................................................................. 43 7.5.5 Statistics on Carrier Power Control .......................................................................... 43

Chapter 8 Common Methods of Interference Analysis .............................................................. 45 8.1 Locating and Analyzing Network Interference by means of Drive Tests ............................ 45

8.1.1 Locating and Analyzing Forward Link Interference.................................................. 45 8.1.2 Locating and Analyzing Reverse Link Interference.................................................. 46

8.2 RSSI Analysis and Locating Network Interference............................................................. 47 8.2.1 Interference Locating & Description......................................................................... 48 8.2.2 Locating & Analysis of Reverse Link Interference ................................................... 48 8.2.3 Analysis of Installation Fault in Equipment Antenna Feeder ................................... 48 8.2.4 Radio Frequency (RF) Components and Some Installation Faults ......................... 49

8.3 Using YBT250 for Interference Locating and Analysis ....................................................... 50 8.3.1 Criteria for Interference Judgment ........................................................................... 50 8.3.2 Common Steps for Interference Tests ..................................................................... 51

Chapter 9 Common Methods of Locating and Troubleshooting Equipment Faults ............... 52 9.1 Methods of Locating Faults in Message Tracing Equipment.............................................. 52 9.2 Common Methods of Locating and Troubleshooting Equipment Faults on the Base Station Side in Network Planning & Network Optimization....................................................... 54

9.2.1 Method of Locating & Analysis of Abis Interface Faults........................................... 54 9.2.2 Methods of Locating & Troubleshooting Baseband Processing Board Faults in Base Station ...................................................................................................................... 55 9.2.3 Locating & Troubleshooting of TRX and HPA Faults in Base Station ..................... 55 9.2.4 Locating & Troubleshooting of CDU and Antenna Feeder Faults............................ 56

9.3 Detailed Inspection of Equipment Board Faults in Base Station ........................................ 56 9.3.1 Power Supply Check................................................................................................ 56 9.3.2 Transmission Link Check ......................................................................................... 56 9.3.3 Check of Received GPS Signals.............................................................................. 57 9.3.4 Check of Cabinet Parts ............................................................................................ 57 9.3.5 Check of Control Interface Module (BCIM) .............................................................. 58 9.3.6 Check of Main Control Clock Module (BCKM)......................................................... 59 9.3.7 Check of Channel Processing Module (BCPM) ....................................................... 59 9.3.8 Check of Resource Distribution Module (BRDM)..................................................... 60 9.3.9 Check of Transceiver Module BTRM ....................................................................... 60 9.3.10 Check of High Power Amplifier (BHPA) ................................................................. 62 9.3.11 Check of Receiving Line Divider Unit (RLDU) ....................................................... 64 9.3.12 Check of Power Supply Unit (PSU) ....................................................................... 64 9.3.13 Check of RF Antenna Feeder Part......................................................................... 65

9.3.14 Check of Satellite Antenna Feeder Part................................................................. 66 9.4 Summary of Experience ..................................................................................................... 66

Guide to CDMA Network Optimization Chapter 1 Overview

Chapter 1

1)

2)

3)

4)

5)

Overview

Aims of this guide:

It is a very practical and complete handbook to guide onsite engineers to finish general tasks of onsite optimization, and to locate & eliminate basic network faults. This handbook is highly pertinent, conformable to the features of CDMA network optimization services in a Regional Dept., a quick guide to both local employees and the original Chinese GSM employees in quickly turning to CDMA network optimization services. As a highly valued book for quick learning of onsite optimization knowledge, it enables engineers to finish tasks and make further progress, guided by advanced Huawei documentation in the actual works. In view of these points, CIS network planning and technical support department organizes all the engineers involved in CDMA in current Regional Dept. to write this handbook based on Huawei documentation and themselves optimization experiences. This handbook attempts to achieve the above goals. This guide is intended for the new employees working on CDMA, the overseas engineers who used to work on GSM network optimization, and local network optimization engineers.

Special thanks to the engineers Yang Xuzhai (member of the editorial board), Wu Shangzhi, and Zhang Chao, who have offered their invaluable experiences, sorted out documents, and written this handbook though their daily works were so busy.

CIS Network Planning Dept.

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Guide to CDMA Network Optimization Chapter 2 Common Settings of Mobile Phones

Chapter 2

2.1

Common Settings of Mobile Phones

Basic Principles of Setting and Using Mobile Phones

During network optimization, onsite network optimization engineers need to activate new mobile phones, perform drive tests, and obtain network signals. Let’s first introduce basic principles of setting and using a mobile phone.

A CDMA mobile phone works in 3 modes: Normal mode, Test mode, and programming mode. Onsite engineers’ main concern is the latter 2 modes. These 2 modes need a corresponding password for entry. Different mobile phones need different passwords to enter into these 2 modes. For a specific password, please refer to a corresponding mobile phone guide or get it directly from a mobile phone provider.

An important function of the test mode is to open the Debug window and obtain the important information about the network signal strengths, including Rx, Tx, and Ec/Io. These information items help us to get necessary network indices conveniently and swiftly.

An important function of the programming mode is to activate a new mobile phone. Let’s introduce basic procedures and principles of the activation: The activation of a new mobile phone consists of MSC registration and mobile phone settings. MSC registration is made by MSC engineers and the Electronic Serial Number (ESN) of a mobile phone should be provided. ESN is identified on each mobile phone and can generally be found when you take away the mobile phone battery. Or you may read ESN by Drive Test tool from the A interface signaling, or from the programming mode of a mobile phone. Upon the completion of MSC registration, a 15-digit IMSI will be returned. This IMSI is used for mobile phone settings. In the programming mode, the activation of a mobile phone requires the settings of several important parameters, including MCC, MNC, 10-digit IMSI, SID, and NID. MCC is the first 3 digits in a 15-digit IMSI, MNC is the fourth and fifth digits in the 15-digit IMSI, and IMSI is the last 10 digits in the 15-digit IMSI. After MCC, MNC, the 10-digit IMSC, SID, and NID (for settings of SID and NID, please contact BSC engineers) have been set, a mobile phone can work normally.

Note: Both SID and NID are mainly used to indicate whether a mobile phone roams. If the SID and NID of a mobile phone are not the same as those of the current network, the mobile phone will show that it is in roaming status, but it can still make calls normally. Therefore, the key of the activation of a mobile phone is to make sure that the 15-digit IMSI is correct.

9


In current network optimization of the CIS CDMA project, we normally use a H100 mobile phone. The following details how to use the H100 mobile phone.

2.2

1) 2) 3) 4)

2.3

H100 Mobile Phone Password

Get SPC CODE by knocking its Password: # #321456987* red on-hook key. Enter the set Nam setting menu. Password: # #20022002 red on-hook key. Enter the debug interface. Password: # #27732726 red on-hook key. Markov call test. Password: # #234.

Basic Settings of Programming Mode of H100 Mobile Phone

Step 1: Press ##321456987* + red on-hook key to get SPC CODE.

Step 2: Press ##20022002 + red on-hook key to pop up the following menus:

1: SET NAM

2: VOICE OPTION

3: DTMF TYPE

Step 3: Select Menu 1: SET NAM. Screen display: SPC CODE?

Step 4: Input the SPC CODE obtained from Step 1 to pop up the following menus:

1: PHONE INFO

2: NAM SETUP

3: SPC CODE

4: SCI

1. Select 1: PHONE INFO to pop up the following menus:

1: ESN

2: CAI VER.

3: FIRMWARE #

4: MODEL #

5: SCM

Select 1: ESN to query the ESN of the mobile phone.

(Note: The ESN of a mobile phone can also be obtained by means of post processing software or by tracing A interface or ABIS interface)

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2. Select 2: NAM SETUP to pop up the following menus:

1: NAM NAME

2: PHONE NUMBER

3: CDMA SETUP

4: HOME SYS

5: PAL INFO

A. Select 1: NAM NAME to directly input any information you want to and press OK; or choose nothing else but the default value. This option is only a tag without any real significance.

B. Select 2: PHONE NUMBER to input the mobile phone number, for example, 0912120071. PHONE NUMBER is the remaining digits after the country code and mobile network code (For example, 46004) are removed from an IMSI, that is, the last 10 digits of the IMSI. This data item is provided by the central equipment office.

C. Select 3: CDMA SETUP to pop up the following menu:

1: MCC #

2: MNC #

3: ACCOLC

4: CHANNELS

1) Select 1: MCC# to input a country code. (For example, 460 for China)

2) Select 2: MNC# to input a mobile network code. (For example, 04)

3) Select 3: ACCOLC, that is, ACCESS OVLD CLASS. This setting cannot be changed and you may select the default value.

4) Select 4: CHANNELS to pop up the following menus:

1:1’ST CH

2:2’ND CH

3:3’RD CH

4:4’TH CH

5:5’TH CH

6:6’TH CH

7:7’TH CH

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8:8’TH CH

9:9’TH CH

0:10’TH CH

Select the menus 1, 2, 3, 4, 5, 6, 7, 8, 9, and 0 respectively to set corresponding frequency channel numbers. After that, press OK to finish frequency channel settings. Then, network searches a frequency channels preferentially from 1 on.

Note: Effective range for settings of frequency channel numbers: 126~275.

D. Select 4: HOME SYS to enter settings

HOME SID 1, used for setting the system SID;

Press OK to pop up HOME NID 1 and set the system NID;

E. Select 5: PRL INFO. This option may be left blank and you may exit.

Step 5: Exit the menu to display NAM SETUP ENDED, and the modifications become valid after the mobile phone automatically restarted.

2.4

2.4.1

2.4.2

2.5

2.5.1

Use of Test Modes of H100 Mobile Phone

Enter the Debug Interface

You may enter ##27732726END to view software and UI versions or enter the DEBUG interface to observe channel number, transmit signal level, receive signal level, and EC/IO, etc.

Markov Call

Currently provided MARKOV function let you store any number in the 99th digit and then type another super password ##234, press the red on-hook key to enter. Besides, OLD 8K is not supported in MARKOV testing.

Settings for Data Service of Mobile Phone

Modem Installation

Add a new Modem in the control panel. Note that you need to install it from a disk and select the file mdmzapp.inf. There are two serial port rates available: 115K and 230K, and you may make selections based on a specific serial port. Generally, the maximum serial port rate on our computer is 115K, but we need to use USB line with 230K rate for demonstrating data service.

12


2.5.2

2.5.3

Establishment of New Connection

Set up a new dial-up connection, with the newly established Modem selected.

Normally, the telephone number is #777. We may create a defaulted account on an AAA server, use huawei as the user name and password.

Settings of Mobile Phone

1. Enter Menu 7: date service to pop up the following menus

1: Receiving mode

2: Flow control

3: Rate

2. Select Menu 1: receiving mode. Set it as “Disabled”;

3. Select Menu 2: flow control. Set it as “Hardware”;

4. Select Menu 3: rate. Select 115,200BPS or 230,400BPS according to the maximum serial port rate.

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Guide to CDMA Network Optimization Chapter 3 Use of Panorama

Chapter 3

3.1

3.2

3.2.1

Use of Panorama

Software Installation and Description

Panorama version: Version 6.1.1.23

USB one-to-four serial port driver

Related documentation: Drive Test Instruction.doc, Drive test data Analysis Description.doc, Pilot Panorama Manual V6.doc, Guide to Use of CDMA1X drive test Equipment (V1.01) .lwp, and Base Station Import Template.xls

Methods of Use

Creating Project

The following figure is a case study of UFA CDMA:

Generally, we select WGS-84 as the ellipsoid, 500000 as False Easting, and 0 as False Northing; Central Meridian is the longitude of the central meridian and is set based on an actual project. The longitude of the central meridian must can be divided exactly by 3 and should generally be set as less than but nearest the actual local longitude; Scale is generally 0.9996. Coordinate System is generally Decimal Long-Lat.

14


3.2.2

3.2.3

Base Station Information Import

Use the base station import file for base station information import. Fill in a base station import file with the following items:

Site Name, Sub Name, Longitude, Latitude, PN, and Azimuth.

After that, save it as a text file separated by tabs. Then, select text file import from panorama by means of Data>import>site.

Equipment Configuration

Equipment configuration involves GPS receiver and H100 test mobile phone.

GPS is set as NMEA/NMEA NMEA 0138 2.0 4,800 baud

Settings of H100 mobile phone: Press Menu and select Menu 7 Data Service to enter Menu 7. Then, select Menu 3 Rate to set the rate as 115,200BPS.

Its serial port configuration is generally shown below:

Serial port configuration should be selected based on actual conditions.

3.2.4 Start Drive Test

You may originate Drive Tests after the configuration of GPS and H100.

First connect the equipment: logging>connect,

If connection has been correctly made, the menu logging>start is available and you may click <Start> to start Drive Tests.

After Drive Tests have begun, generally you may keep 4 windows open: Map, Graph, Temporal Analyzer, and Signaling.

15


3.2.5

3.2.5.1

Introduction to Main Windows

Map window

There are 2 operations in the Map window:

The 1st shortcut button is used to select displayed coverage parameters, for example, RxAGC, MaxEcIo, and TotalEcIo.

The 2nd shortcut button is used to select the base station or map to be displayed.

16


3.2.5.2 Graph window

In Graph, you may right click on Field or Maintain for selection and setting of display content.

3.2.5.3 Temporal analyzer

This window is used to display the EcIo values of the PNs a test mobile phone captured. You may right click on the left half for related settings.

17


3.2.5.4 Signaling

This window is used to display the RxAGC, EcIo, FFER, Adj (transmitter power adjusted) of a test mobile phone, and the branches in Active Set.

3.2.6 Data Playback

First open the window you need to view, for example, MAP serial port.

Select the test data to be reviewed by means of the button on the Standard toolbar.

Employ the Replay toolbar for data playback.

3.2.7 Data Statistics

Select the test data on which statistics should be made by means of the menu Analysis>Statistics>By Data, and select the default value in the following dialog box. Click OK, and you may obtain the following statistical chart:

18


You may click on Distribution button to insert the index distributions in Statistics Value into a document.

Also, you may press Extreme button to insert the index distributions in Extreme Value into a document.

3.3

3.3.1

Summary of Experience

Equipment Connection

During a drive test, the equipment often fails to be connected properly.

First, make sure that the serial port is normal;

Then, check the settings of GPS receiver and H100 test mobile phone;

If the mobile phone fails to be connected even if hardware and settings are both normal, you may perform the following operations: Press the menu of the mobile phone to select Menu 7. Then, select Menu 3 and the rate 115,200BPS. Finally, press the sel button of the mobile phone continuously while clicking the equipment

19


connection button of panorama. Thus, this mobile phone can be connected with panorama.

3.3.2

1)

2)

3)

4)

Some Experience in Evaluating Network Indices

During the Drive Tests, simple judgments can be made to evaluate the network based on the following indices:

Normally, RxAGC (receiving power of a mobile phone) plus TxAGC (transmitter power of a mobile phone) equals around -85dBm. If the sum of the two exceeds -70dBm, it shows that coverage is poor or there may exist interference. Judgment of FFER:

Criteria for judgment of FFER: If the average FER is less than 2%, it is normal; if FER greater than 2%, it is abnormal.

Judgment of voice quality

If voice quality remains poor when FER is less than 2%, the fault may lie in the equipment side.

If FER is greater than 2%, you have to check whether local coverage is poor and determine whether there exists any strong local interference. If all the above factors are eliminated, it shows that network does not work normally and the fault is generally in clock.

About Ec/Io

In a new network or a network with low load, the overall Ec/Io level is required to be greater than -9dB.

If the network load is heavy, the overall Ec/Io level may be required to be greater than -13/-14dB.

20

Guide to CDMA Network Optimization Chapter 4 Common Commands for Modification of Network

Optimization Parameters

21

Chapter 4

4.1

4.2

4.2.1

4.2.2

4.2.3

Common Commands for Modification

of Network Optimization Parameters

This chapter introduces some MML commands commonly used in network optimization, for example, query Commands: BSC information query, base station information query, and cell information query; modification Commands: power modification, neighbor list modification, and channel information modification.

Each command has a specific example which introduces common parameters and mandatory items, any other uncommon parameters or options are excluded.

For detailed meanings of parameters and precautions for the modifications, please read carefully CDMA Network Planning Data Modification System and Guide to CDMA 1X Network Planning Parameter Configuration

Maintenance Console Version and Description

Version of BSC maintenance console: BSC6600V100R002B03D208; installation password: 2002-01-08

For details of parameter configuration, please refer to:

Basic Commands for Information Query

BSC Information Query

Command: LST BSCINF:;

BTS Information Query

Command: LST BSCBTSINF: BTSTP=IBSC, IBTSID=1;

Description: IBTSID is BTS ID and generally we just input BTS ID.

CELL Information Query

Command: LST CELL: CN=1, SCTID=0;

Description: CN is CELL ID and SCTID is SECTOR ID.



22

4.3

4.3.1

Power Parameter Commands

Description and Precautions

These parameters are used to adjust network coverage.

Power is specially represented with the relative gains to the total transmitter power of a sector carrier. Assume that X represents the forward channel gains and Y represents the ratio of this channel power to the total sector power.

-(255-X)*0.25=10logY

For example, if X=227, then Y = 19.9%.

To keep the coverage of various channels consistent, power settings of various channels are generally related to each other:

Synchronization channel gains = pilot channel gains---10dB

Paging channel gains (9,600bps) = pilot channel gains---1.5dB

Paging channel gains (4,800bps) = pilot channel gains---4.5dB

For example, when the pilot channel is set as 227, the synchronization channel = 227---40 = 187; paging channel (9,600bps) = 227---6 = 221.

The general correspondence between X and Y of 3 kinds of channels is shown below:

Pilot Channel Synchronization Channel Paging Channel (9,600bps)

215 10% 175 1% 209 7%

222 15% 182 1.5% 216 10.5%

227 20% 187 2% 221 14%

231 25% 191 2.5% 225 18%

234 30% 194 3% 228 21%

4.3.2 Pilot Channel

Query Command: LST CMFINF: CN=1, SCTID=0, CMFINF=PLTCH;


Modification Command: MOD PLTCH: CN=1, SCTID=0, CRRID=11, PLTCHGAIN=227;

Description: CRRID is Carrier ID, generally 11; and PLTCHGAIN is the pilot channel gains.



23

4.3.3

4.3.4

4.3.5

4.4

4.4.1

Value range: 0~255; adjustable range: 215~234; suggested value: 227

Synchronization Channel

Query Command: LST CMFINF: CN=1, SCTID=0, CMFINF=SYNCH;


Modification Command: MOD SYNCH: CN=1, SCTID=0, CRRID=11, SYNCHGAIN=187;

Description: CRRID is Carrier ID, generally 11 for a single carrier; and SYNCHGAIN is the synchronization channel gains.


Paging Channel

Query Command: LST CMFINF: CN=1, SCTID=0, CMFINF=PCH;


Modification Command: MOD PCH: CN=1, SCTID=0, CRRID=11, PCHGAIN=221;

Description: CRRID is Carrier ID, generally 11 for a single carrier; and PCHGAIN is the pilot channel gains.


Fast Forward Power Control

Query Command: LST RRMINF: CN=1, SCTID=0, RRMINF=FFASTPC;

Modification Command: MOD FFASTPC: CN=1, SCTID=0, CRRID=11, FCHMAXGAINR1=211, FCHMINGAINR1=159, SCHMAXGAINR1=235, SCHMINGAINR1=191;

Description: FCHMAXGAINR1 is the maximum FCH gain 1 while FCHMINGAINR1 is the minimum FCH gain 1; SCHMAXGAINR1 is the maximum SCH gain 1 while SCHMINGAINR1 is the minimum SCH gain 1.

Commands for Neighbor List Parameters

Description and Precautions

Often, there are 3 kinds of neighbor list relation tables:



24

4.4.2

4.4.3

4.4.4

Pilot neighbor list table: Used in idle status.

Intra-frequency neighbor list table: Used for intra-frequency handoff in conversation status of a mobile phone.

Inter-frequency neighbor list table: Used for inter-frequency handoff in conversation status of a mobile phone.

Current CDMA network often has only one frequency channel. Therefore we can only concern about pilot neighbor list tables and intra-frequency neighbor list tables.

In addition, a mobile phone supports a limited number of neighbors, therefore we should set priorities for them.

Query of Neighbor List Relations

Query pilot neighbor list tables in idle status:

Command: LST NBRCDMACH: NBRINF=IDLENBR, CN=1, SCTID=0;

Query intra-frequency neighbor list tables in conversation status:

Command: LST NBRCDMACH: NBRINF=SFNBR, CN=1, SCTID=0;

Addition of Neighbors

Command: ADD NBRCDMACH: CCDMACH="12-12-0-260", NBRCDMACHS="12-12-1-260", SFFLAG=SINGLE, DFFLAG=NULL, NBFLAG=SINGLE, SFRSN=6, NBRSN=6;

Description: CCDMACH="12-12-0-260" means BTSID 12, CELL ID 12, SECTOR ID 0, and Channel number 260 of a service cell; NBRCDMACHS="12-12-1-260" means BTSID=12, CELL ID=12, SECTOR ID=1, and Channel number =260 of a neighbor; SFFLAG=SINGLE represents a unidirectional intra-frequency neighbor, DFFLAG=NULL means that there is no inter-frequency neighbor, and NBFLAG=SINGLE means a unidirectional idle adjacent frequency.

Deletion of Neighbors

Command: RMV NBRCDMACH: CCDMACH="12-12-0-260", NBRCDMACHS="12-12-1-260", SFFLAG=SINGLE, NBFLAG=SINGLE;

Description: Delete the neighbor NBRCDMACHS="12-12-1-260" of the service cell CCDMACH="12-12-0-260".



25

4.4.5

4.5

4.6

4.7

1)

2)

Modification of Neighbor’s Priority

Modify the priority of an idle neighbor:

Command: MOD NBRCDMACHP: CCDMACH="12-12-0-260", NBRCDMACH="12-12-1-260", SEQN=4;

Modify the priority of intra-frequency neighbor:

Command: MOD SFNBRCDMACHP: CCDMACH="12-12-0-260", NBRCDMACH="12-12-1-260", SEQN=4;

Note: In the versions later than overseas BSC B02D202, if there is any repetition of neighbor’s priority added or modified, the system will automatically degrade any repeated priority or a priority put in the rear by one grade. Version D202 and earlier cannot automatically be inserted unless their priorities have been manually adjusted.

Handoff Parameter Commands

Query Command: LST RRMINF: CN=1, SCTID=0, RRMINF=HO;

Modification Command: MOD HO: CN=1, SCTID=0, CRRID=11;

Access Parameter Commands

Query Command: LST SYSMSGPARA: CN=1, SCTID=0, CCMINF=APM;

Modification Command: MOD APM: CN=1, SCTID=0, CRRID=11;


Generally, the above parameters have been modified frequently. For modification of other parameters, refer to the command line tree. Dynamic settings of some command lines may have a certain influence upon the network. If a carrier is reset and BTS is restarted, please follow strictly to CDMA Network Planning Parameter Modification System

Guide to CDMA Network Optimization Chapter 5 Common Commands for Maintenance and Information

Tracing

26

Chapter 5

5.1

5.1.1

5.1.2

5.1.3

Common Commands for Maintenance

and Information Tracing

This chapter introduces some common maintenance operations and commands, for example, signaling tracing and common query commands.

Common Maintenance Commands

This section makes a list of some commands which may be used in maintenance.

Query of Equipment Version

BSC version query:

In Airbridge, click the toolbar About..., and you may query revision information, for example, V200R001;

Press Ctrl+Alt+Shift+F12 at the same time, and you may query details of version information (including OMC version information of BSC and BTS3612/3606/3601), for example, V200R001C02B012.

Query of BTS board software version:

In Airbridge, execute GET BTSBRDVER: BTSID=0,BRDTP=BCKM, BRDID=0;

And you may query the software version of main control clock module BCKM0 of base station 0, for example, V200R001C02B112 usually represents the version of a base station.

Query of Resource Status of Sector Carrier:

Command: DSP RES

Description: All sector carrier results of all base stations will be queried if no cell No., sector No., or carrier No. is input.

Query of BTS Site Name and O&M IP

Command: LST BTS


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5.1.4

5.1.5

5.1.6

5.1.7

Description: All base stations will be queried if there are no base station No. and base station name entered.

Query of Information about PN, SID, NID, and LAC:

Command: LST CELL

Description: All cells will be queried if no shelf No., BTS ID, CELL ID (BTS ID is the same as CELL ID), SECTOR ID, or PN CODE entered.

Query of E1 Link Status:

Command: DSP E1T1STAT

Description: The shelf No., slot No., and board type must be input. This command is used to query whether a base station has normal transmission.

Query of Longitude/Latitude, Sea Level Elevation, and Number of Locked Satellites of a Base Station:

Command: DSP BTSBRDSPECSTAT

Description: BTSID is mandatory. Select BCKM. BRDID generally has one board, that is, Board 0.

Normally, a base station traces at least 4 satellites. If weather is not good (For example, when there are thick clouds), the satellite signals may not be strong enough. The satellite unlocking for a long time may lead to unsynchronized base station, which results in call drops during handoffs. If the satellite unlocking alarms are often generated in good weather, we need to check the installation of GPS antenna feeder.

Query of Realtime Forward Power Load of Sector Carrier; Occupations of Channels, CEs, and WALSH Code Channels; Channel Handover

Description: CELL ID, SECTOR ID, and CARRIER ID must be input. This command may be used to visually view the current occupation of various channels at this sector carrier, together with forward load and number of users, including voice users and packet data users occupying SCH.

Command: DSP RADIORESINDICATION


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5.1.8

5.1.9

5.1.10

5.2

5.2.1

Carrier Blocking:

Command: BLK RES

Description: CELL ID, SECTOR ID, and CARRIER ID must be input, and a blocking type selected. HIGH represents immediate blocking and interruption of all calls. When selecting NORMAL, we need to set the time, within this time period, the existing calls may be held, but new incoming calls will be rejected. When this time expires, all calls will be forcedly interrupted and carrier blocked. LOW means new incoming calls are rejected and blocking will not take place until all users involved in conversation are released.

Carrier Unblocking:

Command: UBL RES

Description: CELL ID, SECTOR ID, and CARRIER ID must be input.

Start RSSI Automatic Realtime Tracing:

Command: STR BTSRSSITST

Description: BTS ID, LOCAL CELL ID (the same as CELL ID and BTS ID), SECTOR ID, CARRIER ID, Threshold Adjust, and TEST TIME must be input. After the execution, files will be saved in D\AIRBIRDGE\Services\BTSRSSI of BAM. Different from RSSI tracing (output once per second) from BAM TELNET to a base station, the tracing result here is output once per minute.

End tracing Command: STP BTSRSSITST. A carrier should be specified.

Signaling Tracing

Signaling tracing is often needed in analyzing network faults and it is generally implemented in 3 ways: 1) from CBSC operation maintenance console, 2) from CBSC test desk, and 3) by message tracing function of Drive Test tools. Drive Test tool tracing is specially introduced by other documents, therefore this section introduces basic operations performed in message tracing by means of the BSC operation maintenance console and the BSC test desk.

CBSC Operation Maintenance Console

On [Maintenance] of the BSC operation maintenance console, open “Tace” in the command tree: “cdma 1x BSC maintenance tool navigation tree” to implement the


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5.2.2

1)

2)

3)

message tracing of various interfaces. The common interfaces for network optimization tracing are Um interface, Abis interface, and A1 interface:

Um interface tracing:

Double click “Um Interface Tracing”, open the dialog box, and input the IMSI of the mobile phone to be traced to enable tracing. You may double click one message to view its content or close the message window to terminate the tracing.

Abis interface tracing:

Double click “Abis Interface Tracing” and input the IMSI of the mobile phone to be traced to enable tracing. You may double click one message to view its content or close this message window to terminate the tracing.

A1 interface tracing:

Double click “A1 interface Tracing” and input the source signaling point of the A1 interface tracing in the dialog box to enable tracing. You may double click one message in the message output window to view its content or close the message window to terminate the tracing.

Tracing files are saved in Airbridge/outputfile/Trace/Um, Abis or A1. For different CBSC versions, the formats and saving directories of tracing files may be different.

Message review:

In “Trace Review” of a command tree, there may be review of tracing messages of various interfaces. A file saving directory cannot be modified, therefore a tracing file should be copied to this directory before you open it.

For details, please refer to Background Tracing Operation Guide

CBSC Test Desk

Connect BAM:

Run CbscTest, select the menu: connect BAM server, and input the IP address of the BAM server;

Connect SPU:

Select the menu: Connect New Debugging Window and select the shelf No., slot No., and type of board.

Print switch settings:

Command input: SET. Subcommand: DIRECTION. Output Direction: TO_TESTDESK (output to the test desk);


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4)

Settings of output direction consist of TO_TESTDESK (output to the test desk), TO_SERIAL (output to a serial port), TO_BOTH (output to both directions), and TO_NULL (shielding output).

Command input: SET. Subcommand: LEVEL. Output level: ALL;

After executing the above commands, the test desk outputs the following results:

[.TDSK.] Set Output Level success! Output Level = ALL [2002-08-28 21:48:56]

The output levels of the test desk consist of NULL (shielding output), ALL (information level), WARNING&ERROR (alarm level), and ERROR_ONLY (error level). Default output level: “WARNING&ERROR (alarm level)”.

Command input: SET. Subcommand: PID. PID switch block: put a tick at the front of PID (such as CCM, LAC, and RRM) to be selected.

After executing the above commands, the test desk outputs the following results:

[TDSK] Set Pid Output Switch success! PID (60) = SWITCH_ON [2002-08-28 21:45:40]

Report Saving In tracing of different types, tracing message content needs to be saved. Report

Saving may be enabled by click “ ” button before tracing is enabled.

Or right click to enable Report Saving.

5) Call tracing:

Call tracing consists of automatic tracing and manual tracing. The automatic tracing system automatically prints the information related to the call flow of the mobile phone accessed while manual tracing means manual input of the IMSI of the mobile phone traced. The maximum of 10 mobile phones can be traced simultaneously. Manual tracing has a higher priority than automatic tracing.

Automatic tracing:

Command: ATOTRACK. The command codes include enabling automatic tracing, disabling automatic tracing, and querying automatic tracing.

Manual tracing:

Command:

Start: STR TRACK, input the MSIN (the last 10 digits in an IMSI, and every two digits are separated by a space) of the mobile phone traced. Subcommand code: information element, that is, the flow type to be traced. Message content: Select whether to print the message content of various internal interfaces in a call flow.

Stop: STP TRACK, that is, enter MSIN.


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6)

After call tracing is over, Report Saving will be terminated too (the method is similar to the starting of Report Saving).

Files are saved in Trace under the CBSC test desk folder

CSL tracing:

CSL refers to Call Survey Log and prints call-related information when a call is released.

CSL is enabled by default when SPU system is started.

Enabling CSL: Input STR CSL after SPU is connected.

Disabling CSL: Input STP CSL after SPU is connected.

Begin Report Saving

Enable CSL output STR CSL, as shown below

Figure 5-1 Enabling CSL Tracing

Disable CSL output STP CSL.

Terminate Report Saving

Note:

Too much print information may affect normal system running. It is recommended to adopt selective tracing, that is to avoid busy hour tracing if you are unclear about when and where faults often occur, and the time for tracing should also not be set too long.

Since a test desk performs direct operations to a board and this may lead to certain risks to the network running equipment. Therefore, clients are generally prohibited from using the test desk.

For details of a test desk, please refer to Guide to Use of CBSC Debugging Tools.

An analysis of message tracing flows requires a good knowledge of calls.


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5.3

5.3.1

5.3.2

5.3.3

Realtime Tracing of Base Station

By means of TELNET to a base station on BAM, we may trace the transmitter power, RSSI, and FER of the base station.

Open WINDOWS start menu: Run and input:

IP address of telnet base station

User name: system

Password: system

Tracing of Transmitter Power:

Start: str infotrace: brdtp=btrm, brdid= slot No., item="power"

Stop: stp infotrace: brdtp=btrm, brdid= slot No., item="power" or close this window

brdid should be correctly input according to the actual board position. Btrm slot in 3 sectors may be 0 4 8 or 1 5 9

RSSI Tracing:

Start: str infotrace: brdtp=btrm, brdid= slot No., item="rssi"

Stop: stp infotrace: brdtp=btrm, brdid= slot No., item="rssi" or close this window

Here, RSSI tracing outputs values once per second and will be automatically disconnected after a period of time (generally around 10 minutes). Long-term tracing demands activation of this window, for example, press Enter once every few minutes.

FER Tracing:

Start: str infotrace:brdtp=bcpm,brdid= board No., item=”TCHRVSFER”

Stop: stp infotrace:brdtp=bcpm,brdid= board No., item=”TCHRVSFER” or close this window

The board No. here is not the slot No. and generally there is only one BCPM numbered 0.

For details, please refer to Guide to cdma2000 BTS3612 Near-end Maintenance Commands

Guide to CDMA Network Optimization Chapter 6 Common Used Methods for Data Service Optimization

Chapter 6

6.1

6.2

Common Used Methods for Data Service Optimization

Description

Many parameters may be modified during the CDMA data service optimization process. We describe the modification of several main parameters during data service optimization here. For specific parameter descriptions and further optimization, please refer to the guide CDMA1X BSS Network Planning Parameter Configuration Suggestions.

Optimization of Goal FER of Data Service

The goal FERs of forward and backward SCHs can be set by the data rates. The goal FER of data service may be set as 1%~10% or higher. In previous versions, the same goal FER, for example, 5% may be set for different data rates. In C03 version, different values of goal FER may be set for different data rates. Generally speaking, the lower a rate is, the lower its goal FER is. Please look at the following example,

Data Rate Destination 1X 1%2X 2%4X 2%8X 3%16X 5%

A higher goal FER may become mild at the RLP layer, whose retransmission mechanism may greatly reduce the FER at the physical layer. This makes an upper layer with a lower error ratio and decreases the burden at the TCP layer. For high-rate data, the goal FER may be set higher to decrease the allocation of forward power, but throughput is decreased as a result of repeated retransmissions. For low-rate data, the goal FER should not be set as too low because their throughput in air interface is not high enough. A very low goal FER may lead to repeated retransmission of RLP and this makes throughput lower.

The default settings of the system are shown above, with forward ones same as backward ones.

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6.3

6.4

6.5

Optimization of Network Load Threshold

Data service occupies very many power resources, therefore the power fluctuation is huge. Network load control is aimed at making data service not excessively occupy the network power resources. There is great power fluctuation in actual network and too rigorous load control restricts the allocation of data service rates. In actual optimization process, load control of data service rates may be gently liberalized. The following example is the optimization of a new network. Network traffic is too low, therefore load limit is modified as 100%, that is, no limit, to increase data service rates on the whole:

MOD SCH: CN=1, SCTID=0, CRRID=11, FWDBDR1XVLV=100, FWDBDR2XVLV=100, FWDBDR4XVLV=100, FWDMID1XVLV=100, FWDMID2XVLV=100, FWDMID4XVLV=100, FWDMID8XVLV=100, FWDCEN1XVLV=100, FWDCEN2XVLV=100, FWDCEN4XVLV=100, FWDCEN8XVLV=100, FWDCEN16XVLV=100;

If “Turn on the new load control algorithm switch” is used, the above parameters are still not functioning at all, you may modify the relative value of SCH admission threshold (Default value: 100, that is, 10%). If high-speed data service needs to be allocated where the coverage is poor, you have to change the parameter with the following command:

MOD FLDCTRL: FWDSTOBTHR=100;

Optimization of Time Parameters for Allocating Data Traffic channel

Allocation of data traffic channels requires 2 time parameters, preparation time and duration period. To increase the transmission rate of data service, preparation time is expected to be as little as possible while duration period should be as great as possible. In current system-defaulted parameters, the preparation time is 20 and the duration is 64. These 2 parameters may be properly adjusted in actual optimization to increase transmission rate. The following example shows the adjustment of these 2 parameters. That is, the preparation time is adjusted as 10 and the duration as 128 to increase the transmission efficiency of data service. Note that the preparation time for our equipment in actual optimization generally should not be less than 9.

MOD SCH: CN=1, SCTID=0, CRRID=11, SIGDL=10, TDL=128

Optimization of Threshold for Pilot Strength Allocation

The important parameters for pilot strength rate allocation threshold in data service consist of the central pilot strength threshold and the edge pilot strength threshold. If

34


the coverage effects of Ec/Io are better than the central pilot strength threshold in a cell, a high-rate services will be allocated; if the coverage effects of Ec/Io are worse than the edge pilot strength threshold in a cell, a low-rate data services will be allocated; if the coverage effects of Ec/Io are between the central pilot strength threshold and the edge pilot strength threshold, a medium data service rates will be allocated. In system-defaulted values, the central pilot strength threshold is -7dB and the edge pilot strength threshold is -10dB. High-rate service is 16 multiples, low-rate service is 4 multiples, and medium-rate service is 8 multiples. In an actual network optimization process, the allocation threshold may be adjusted based on network load level and Ec/Io coverage. The following example shows how to increase a data service rate by decreasing the allocation threshold in an area with poor coverage. In this case, the central allocation threshold is (64-46)/2=9, that is, -9dB; the edge allocation threshold is (64-42)/2=11, that is, -11dB.

MOD SCH: CN=1, SCTID=0, CRRID=11, CENPLTTHRS=46, BDRPLTTHRS=42;

6.6 Optimization of SCH Continuation in Data Service

SCH data are transmitted in the form of data Burst. After data burst within a certain finite duration is over, there will be some gaps in the time axis when new SCH data burst is applied. SCH continuation means continuing data burst within a finite duration to enable users to transmit data over SCH channels without any interruption. The continued SCH fills in the gap generated when the original SCH is released and reapplied and increases the time efficiency of SCH transmission. At present, we have implemented forward SCH continuation alone. If SCH continuation function is enabled, SCH active release should be disabled, that is,

MOD MCHM: SCHRELBYFERSW=OFF, SCHRELBYPILSTSW=OFF, SCHRELBYLOADSW=OFF, SCHEXTENSIONSWITCH=ON;

In addition, when SCH continuation has been enabled, you also need to set SCH continuation duration (Default value: 32 frames), overlapping duration of SCH continuation (Default value: 2 frames), and time for SCH assignment enabling (Default value: 3 frames). Note that the SCH continuation duration is different from the SCH duration mentioned in Section 6.4. The SCH continuation duration refers to the SCH duration (fixed 32 frames) when wireless environment and load status satisfy continuation conditions, and the system adopts the SCH continuation algorithm. The SCH duration, however, means that when wireless environment and load status do not satisfy continuation conditions, the system initiates an SCH application and calculates the SCH Duration according to the amount of data in a buffer and SCH transmission delay. In setting SCH continuation parameters, please pay attention to the following 2 relational expressions. Otherwise, data transmission may encounter a big gap.

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1)

2)

6.7

"SCH continuation burst duration" --- "SCH continuation overlapping duration"> "signaling delay". "Advanced offset of SCH continuation assignment time" < "signaling delay" + "former/latter SCH overlapping time ".

Commands:

MOD MCHM: SCHEXTENSIONSWITCH=ON, SCHEXTENSIONDURATION=10, SCHEXTENSIONOVERLAP=2, SCHEXTENSIONJUDGETIMEOFFSET=3;

There is a correspondence between parameter inputs of SCH continuation burst duration and actual frame values: 4~4 5~5 6~6 7~7 8~8 9~16 10~32 11~64 12~96 13~128 14~256. Here 10 represents 32 frames.

Description of Data Service Test Performance

During the testing and optimization of data services, the air interface rate should be distinguished from the data service rate of the application layer. Meanwhile, you need to be clear about the layers consumption and transmission efficiency during the transmission of data service.

CDMA2000 1X supports the maximum rate 163.2kbps (an air interface rate). When data service is transmitted from the application layer to an air interface, much consideration should be given to a corresponding layer consumption: retransmission due to error codes at the air interface, and transmission efficiency at the air interface. Therefore, the physical layer has a different transmission rate from that of the application layer.

On the whole, the following formula is used to represent the whole service transmission and to calculate data service rates in different conditions.

Tapp=Tair*(1-Rlayer)*(1-Rrepeat)*Rrate

Tapp is the data service rate at the application layer, Tair is the air interface transmission rate, Rlayer is the consumption from the application layer to the air interface physical layer, Rrepeat is the retransmission rate due to error codes at the air interface, and Rrate is the transmission efficiency at the air interface.

Normally, we typically take Rlayer (the layer consumption) =13%, Rrepeat (retransmission efficiency due to error codes at the air interface) =5% (5% as the goal FER of data service), and Rrate (air interface transmission efficiency) =93%. Thus, we may make calculations and obtain the rough average rate at the application layer, that is, Tapp=163.2*87%*95%*93%=125.4kbps. Therefore, the data service transmission rate we have tested by employing general test methods is the rate at the application layer. In actual optimization, certain distinctions must be made. If clients have any questions, corresponding technical clarification is necessary.

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Currently, basic standards for data service network performance are recommended as follows and can be taken as reference for optimization:

Throughout (kbps) Evaluation

<70 Poor

70-100 Good

>100 Very good

Packet Size Round Trip Delay (ms)

2Bytes 200-240

32Bytes 240-300

60Bytes 280-530

180Bytes 680-850

400Bytes 990-1,240

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Guide to CDMA Network Optimization Chapter 7 Common Used Methods for Traffic Statistics Analysis

Chapter 7

7.1

7.2

7.3

Common Used Methods for Traffic Statistics Analysis

Implementation of Traffic Statistics

Generally, we register, query, and modify traffic statistics in 3 modes: OMC command line tool (MML), OMC performance management system, and M2000 performance management system.

M2000 performance management system has the most powerful functions and is most commonly used tool. This chapter introduces various operations of M2000 in making traffic statistics, and basic analysis.

Common Operations of Traffic Statistics

M2000 provides diversified operations of traffic statistics tasks, including the creation, modification (name, object), and query (task information, task result) of traffic statistics, alarm setting, and task deletion/activation/suspension.

Note that traffic statistics needs registration again each time when BSC is reset and data are added again. This is the disadvantage of performing M2000 traffic statistics. On the contrary, batch commands can be directly executed if an operation maintenance console is used.

For details of traffic statistics, please refer to Guide to M2000 Traffic Statistics Operations.

Common Indices for Traffic Statistics

The common traffic statistics indices in wireless network optimization are directed against 2 parts, either based on BSC or based on sector carrier. In addition, statistics on paging success rate is generally obtained from MSC since BSC’s paging success rate is not necessarily accurate. For example, if 2 BSCs are in the same location area (same LAC), paging requests will be sent to the 2 BSCs, but paging responses are made by one BSC only. Thus, BSC paging success rate will be lower than the MSC paging success rate and cannot reflect the actual conditions.

In BSC-based traffic statistics, the following indices should be registered: statistics on BSC traffic & soft handoff ratio, Circuit Switched (CS) call establishment success rate, Packet Switched (PS) call establishment success rate, CS wireless call drop rate,

38


statistics on success of soft handoff within BSC and between BSCs (if there is only one BSC, Intra-BSC soft handoff statistics should be registered), statistics on success of hard handoff within BSC and between BSCs (no registration is needed if there is no hard handoff), paging success rate, and traffic channel congestion rate.

In Carrier-based traffic statistics, the following indices should be registered: statistics on carrier traffic & soft handoff ratio, Circuit Switched (CS) call establishment success rate, Packet Switched (PS) call establishment success rate, CS wireless call drop rate, statistics on success of soft handoff within BSC and between BSCs (if there is only one BSC, Intra-BSC soft handoff statistics should be registered), statistics on success of hard handoff within BSC and between BSCs (no registration is needed if there is no hard handoff), statistics on Carrier power control, statistics on Carrier forward load, and traffic channel congestion rate.

We suggest that the MSC paging success rate should be registered.

Other indices are registered as needed. Take the CDMA WLL system for example, statistics may be made on modes of voice coding to realize how voice quality is affected by a coding scheme.

7.4 Method of Traffic Statistics Analysis

Traffic statistics analysis is one of the main means of finding network problems, and it is also the basis and standards for optimization. For details of traffic statistics analysis, please refer to Guide to CDMA 1X Traffic Statistics Analysis -20030710-A-1.3. This chapter is focused on the basic methods for traffic statistics analysis.

Traffic statistics analysis should be made from the whole to the parts:

First, you need pay attention to the busy hour BSC indices and view whether the CS call establishment success rate, wireless call drop rate, and soft handoff success rate are normal. If they are abnormal, then view main causes for call establishment failures, call drop causes, and handoff failure causes. Meanwhile, check related data configurations based on failure causes. For details, see the indices analyses in the following section.

For those abnormal indices, you need to view the BSC statistics first and then check the statistics on the carriers in various sectors to find whether all carriers or partial carriers are abnormal. If all carriers are abnormal, it is quite possible that the BSC is at fault or network-wide status is abnormal (For example, the whole network is interfered); if only partial carriers are abnormal, one possibility may be from the base station, for example, equipment, transmission, and the other possibility may be the interference. View alarm information to make sure whether any equipment or transmission is abnormal. Then, view the carrier traffic, forward load, and carrier

39


power statistics to make sure whether there is any heavy load of traffic in a sector. View the carrier power control statistics and analyze whether there exists any backward interference within a sector based on RSSI and backward FER.

7.5

7.5.1

7.5.2

1)

Analysis of Main Indices

This section makes an elementary analysis of some main indices.

Success Rate of CS Call Establishment

Generally, we are mainly concerned about the voice call establishment success rate in call establishment success rate. Normally, if the voice calls are normally established, there will be no problem with data service call establishment. If there is a low rate of packet call establishment but a normal success rate of voice call establishment, please check PDSN, AAA server and other pieces of PS domain equipment based on establishment failure causes.

CS call establishment success rate = [CS call establishment success times/ CS call attempts]*100%

Different operators present different requirements for call establishment success rate. For example, either 92% or 95% is required in different Unicom local networks. It is recommended that 95% should be taken as the standard to guide the equipment buyer.

Call Drop Rate of Wireless System

Call drop rate consists of the wireless system call drop rate and the system call drop rate. The system call drop rate refers to the total number of call drops resulting from various factors in the whole network system, including wireless system causes and other causes. The call drops are mostly caused by wireless factors, therefore our main concern is about the wireless system call drop rate, and the traffic statistics is directed against wireless system call drop rate.

The wireless system call drop rate is calculated as follows:

Wireless system call drop rate = [number of call drops from wireless causes/ (call establishment success times + successful handoff times between BSs)]*100%

Generally, the wireless system call drop rate in busy hour should be lower than 1%.

In a wireless system, the total traffic channel call drop times resulting from wireless losses and handoff factors mainly include the following statistics causes:

Excessive frame errors:

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In system-defaulted setting FMR, after various branches are combined, call drop (call release) may occur if there are more than 270 Erasure (bad) frames out of 300 reverse link frames. This threshold may be modified. Query commands: LST FRMINFO. Modification command: MOD SDUMDC. Possible causes for too many error frames may be reverse link error, forward link error, forward interference making a mobile phone disable a transmitter, and which causes FMR counting it as an error frame, or Abis link fault leads FMR to statisticize it as an error frame, excessive load, reverse link interference, pilot pollution, improper neighbor list settings, and handoff problems.

2)

3)

4)

5)

6)

Too many null frames:

Possible causes are poor wireless environment, a base station being unable to capture mobile phone signals, or too much delay between soft handoff branches. If call drop is caused by too much time delay between branches, the FMR reverse frame combining timer may be properly lengthened. Query command: LST FRMINFO. Modification command: MOD SDUFPMDC. In the versions prior to D302, if there is too much delay between handoff branches, FMRs cannot be combined, but statisticized as a null frame. Call drop will occur if there are more than 300 null frames. This threshold may be modified. Query command: LST FRMINFO. Modification command: MOD SDUMDC.

Too high of MARKOV FER value

markov FER means that any received frames are compared with those frames locally generated and those are considered as bad frames if the former ones are different from the latter ones. If no frame has been received, it will be statisticized as a bad frame. The default value is that TCH ERR will be reported when 95% of 500 frames are bad frames within 10 seconds, and this value may be modified at a test desk. It is generated for basically the same reason as in 1) Excessive error frames, or because of inaccurate system clock.

No frame is received

If FMR has not received any data frame from a individual BTS within 80ms, it will be directed against to a single branch instead of releasing the whole call. Possible causes: Base station fault, transmission interruption, and AAL2 link data configuration problem between BSC and BTS.

Abis link abnormality

When detecting any fault in internal processing, a base station itself will report “Abis bts release request”. Call drops thus caused will be attached to this value. If an Abis interface is abnormally interrupted, for example, broken fiber, BSC does not know this and it appears that FMR has not received any data frame. This will be included into radio link causes.

A interface fault

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Possible causes: A interface reset initiated by the equipment or human; A interface fault or link broken resulting from transmission fault or MSC/BSC equipment fault.

7) Others

7.5.3

A detailed analysis of other causes should be made based on the onsite conditions with signaling tracing, call quality tests and drive tests.

Soft Handoff Performance

Generally, soft handoff performance involves 2 indices: soft handoff ratio (to be viewed in BSC traffic statistics) and soft handoff success rate.

Soft handoff ratio is calculated as follows:

Soft handoff ratio = [traffic channel bearer traffic (including soft handoff)---traffic channel bearer traffic (excluding soft handoff)]/ [traffic channel bearer traffic (including soft handoff)]*100%.

Soft handoff performance is optimal when the theoretical value is 30%. In practice, 20%~40% are relatively reasonable.

Too low soft handoff ratio cannot improve edge coverage greatly and the advantages of CDMA soft handoff cannot be employed to the greatest extent. Too high soft handoff ratio, however, may consume too many resources, such as CE resource and WALSH code channel resource, and increases network load.

When the soft handoff ratio is too low, the requirements for soft handoff may be slightly lowered, for example, decrease T_ADD and T_DROP values or increase T_TDROP. As to engineering related aspects, antenna feeder parameters may be adjusted to increase the overlapping coverage area of base stations.

If the soft handoff ratio is too high, antenna feeder parameters may be adjusted to properly decrease the overlapping coverage area by soft handoff, and soft handoff thresholds may be properly adjusted, for example, increase T_ADD and T_DROP values or decrease T_TDROP. Or you may enable dynamic soft handoff. As a result of dynamicness and performance relevance in the CDMA system, other performances may deteriorate while the soft handoff ratio is decreased. For example, edge coverage may slightly decrease, which leads to a higher rate of call drops. Therefore, adjustments should be made based on overall network performance.

Soft handoff success rate should be generally greater than 99%.

Soft handoff success rate is calculated as follows:

System soft handoff success rate = [ (times of successful soft handoff within BS + times of successful soft handoff between BSs)/ (number of soft handoff requests within BS + number of soft handoff requests between BSs)]*100%.

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If there is too low a soft handoff success rate, possible causes include poor wireless environment, Abis interface fault, and A3/A7 interface fault leading to signaling interaction failure; system congestion, improper settings of system and mobile phone timers (For example, CCM waiting for completion of mobile phone handoff: CCM_T_WT_MS_HO_CMP), and fault coordination between terminals and system (For example, different carriers may be configured with different handoff indication messages, which a terminal may be unable to recognize). Among other possible causes are a neighbor list which fails to be configured, unreasonable neighbor list priority, improper settings of search windows, improper settings of handoff parameters, and pilot pollution, etc.

7.5.4

7.5.5

Traffic channel Congestion Rate

The traffic channel congestion rate is calculated as follows:

Traffic channel congestion rate=[ traffic channel congestion times / traffic channel occupation request times ]*100%

The traffic channel congestion rate is the ratio of the total times of unsuccessful allocation of traffic channels to those of traffic channel allocation requests resulting from insufficient Walsh Codes, insufficient power, insufficient traffic channels, insufficient encoders, and insufficient transmission links between BTS and BSC. In these cases, a mobile phone is either the caller or the callee, or implements handoff. Or SMS receives/sends messages over TCH.

Insufficient WALSH codes: This does not occur in normal cases, but may occur when data service is applied.

Insufficient forward power or insufficient traffic channels: possible causes may be too heavy load (adjustment of coverage controlled, load balance, and expansion), too great a common channel power (reduce the ratio of common channel power), too high a soft handoff rate (increase the soft handoff thresholds to reduce the soft handoff area), improper forward power control parameters (decrease forward transmitting power), forward interference (eliminate interference), and equipment fault (troubleshooting).

Surface link congestion: surface links, such as A interface, Abis interface, and A3 interface, have insufficient capacity or become faulty.

Improper settings of various interface timers: Mainly hard/soft handoff timers and various interface resource application timers.

Statistics on Carrier Power Control

Statistical results of carrier power control include Eb/Nt, RSSI, FER, and transmitting power of various carriers.

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Eb/Nt takes dB as its unit and RSSI value needs converting as follows (RSSI -120) dBm. FER takes 1% as its unit and the transmitting power is dBm.

RSSI: The RSSI value in traffic statistics is the average within a measurement period and is not real time value, but the average may roughly tell us whether there is any fault. For example, too small an RSSI value (For example, lower than 7) may show equipment installation fault, that is, the antenna feeder system may be not firmly connected; if there is a continuously high RSSI value, for example, higher than 20, it is quite possible that there exists some interference or equipment fault (For instance, installation or equipment self-excitation). If RSSI statistics is found abnormal, realtime RSSI tracing should be enabled in a base station for further fault locating. For analysis details, please refer to interference analysis.

FER: The average FER value should be 1% or lower. For analysis of too high FER, please refer to analysis of causes for too high FER in Section 7.5.2.

Transmitting power: The transmitting power in empty load condition should include common channel power only. For example, when the pilot channel power, synchronization channel power, and paging channel power (paging rate of 9,600kbps) are respectively 20%, 2%, and 14%, the average total transmitting power is 20W. The transmitting power with empty load should be around 38.6dBm and that with full load should be around 43dBm. The transmitting power in traffic statistics should be between 38.6dBm and 43dBm. When system load is increased, the transmitting power may exceed 43dBm, but it may not more than 45dBM because TXR will perform power limitation to protect a power amplifier if it is more than 45dBm. If the transmitting power is excessively high, the possible causes may be that the load is too high or the equipment is at fault.

For analysis details, please refer to Guide to CDMA 1X Traffic Statistics Analysis.

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Guide to CDMA Network Optimization Chapter 8 Common Methods of Interference Analysis

Chapter 8

8.1

8.1.1

Common Methods of Interference Analysis

In CDMA network, network interface may appear the same as other faults. Here, some cases of network optimization are given to introduce how to locate network interface and network performance faults by means of Drive Tests and network RSSI analysis; in addition, there is a brief description of how to use YBT250.

Locating and Analyzing Network Interference by means of Drive Tests

Drive Tests are the important means of network optimization. Basic network information collected by means of Drive Tests is the receiving power, transmitting power, adjustment of transmitting power, FER of a mobile phone, and related signaling information. During Drive Tests, any information tested may be used to locate possible forward link interference and reverse link performance faults in the system.

Locating and Analyzing Forward Link Interference

Important information collected by means of Drive Tests includes forward transmitting power from BTS, transmitting power from mobile phone, and FER of a mobile phone.

These parameters are related to each other. The receiving power of a mobile phone represents all received powers within the frequency band of 1.2288M. If all of them are valid, then Ec/Io will keep a good level. If the forward link receiving power Rx is good, but Ec/Io is very poor, this generally shows that other energies are leaked to this 1.2288M bandwidth. Specifically speaking, the network involves in forward interference.

If there exists any forward interference, Ec/Io could be very poor and the system FER could be rather high. The following example shows a typical forward interference scenario. In this case, the forward receiving power is as high as -87dBm, but Ec/Io is as poor as -14dB. Meanwhile, the FER of a mobile phone is as high as 18% and the coverage levels tested in this area are quite different at different time periods. These show that there exists severe forward interference in this area at different time segments. Frequency scanning shows that there exists severe intermittent forward interference in this area.

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8.1.2 Locating and Analyzing Reverse Link Interference

CDMA is based on highly effective mechanism of power control and this makes a mobile phone somewhat related to a base station in terms of their transmitting power. In good radio transmission environment, general empirical data show that it is considered normal if Rx+Tx is –75~ –85 dBm. In case of Rx+Tx>-75, it is generally considered that there may be some faults in reverse links in the system.

The following 2 figures are the analysis of typical test results.

The two areas close to each other. They have equivalent forward Ec/Io, similar coverage size, and almost the same Rx receiving strength. However, the transmitting power of the mobile phone serving Base Station B is around 20dB higher than that of the serving Base Station A. For Area A, Rx+Tx=-81, which is normal. For Area B, Rx+Tx=-67, which shows there may be some faults in reverse links of this base station.

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Too high a transmitting power of a mobile phone is generally caused by poor reverse link sensitivity, which leads to the demand on a higher power. The factors which affect reverse link sensitivity: In terms of parameters, too higher of Eb/Nt values or the FER threshold is set too high; in terms of network, there may be severe reverse link interference; in terms of the equipment, connectors are not tightened, water penetrates an antenna, or the equipment has aging.

For this case, through the monitoring the reverse link interference of the base station continuously, the results show that the RSSI of the base station received is as great as -85dBm and there exists severe reverse link interference. It shows us that a detailed analysis of Drive Test data may help locate reverse link interference and other reverse link faults.

8.2 RSSI Analysis and Locating Network Interference

RSSI values show the reverse link received field strength within the frequency band of 1.2288M in a base station. We may get it from the BTS RSSI log by means of the command STR BTSRSSTTST.

The value of RSSI directly reflects the reverse link load and reverse link interference in current network. On the other hand, if the antenna feeder equipment fails to be installed correctly or antenna feeder performance does not conform to the specifications concerned, we may find this preliminary information by tracing the analysis of RSSI. The experience of onsite network optimization is introduced for how to locate network interference fault, equipment installation fault, and antenna performance fault by means of RSSI analysis.

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8.2.1

8.2.2

Interference Locating & Description

In a clean radio electromagnetic environment, the electromagnetic background noise level may be calculated as follows: PN = 10log(KTW). The background noise level of the CDMA system in normal indoor temperature is -113dBm/1.2288M. With the receiver noise coefficient (5dB) and wireless environment background noise fluctuation level (2dB) taken into account, the monitor results of RSSI in normal cases should be around -106dBm. The influence upon system load generally does not exceed 8dB, that is, around -98dBm. With the margin of 3dB taken into account, that is, the average RSSI does not exceed --95dBm if the system works normally in heavy load. Otherwise, the severe reverse link interference exists in the network.

Locating & Analysis of Reverse Link Interference

The following figure is a typical case of RSSI analysis when there exists a reverse link interference in the system and the onsite RSSI level exceeds -90dBm for a long time period. Wireless monitoring results show that the reverse link interference is severe on the site.

8.2.3 Analysis of Installation Fault on Antenna Feeder

It can be learnt from the previous analysis that even if it is in the best case, the average level of RSSI generally cannot be less than -108dBm. With the margin of 2dB taken into account, the average level of RSSI cannot be lower than -110dBm. If there may be some faults in equipment installation, for example, antenna feeder parts are not firmly installed, the receiving power may be very low. If the average

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RSSI is lower than -110dBm for a long time period, it shows that the fault necessarily lies on antenna feeder parts..

The following figure shows a typical RSSI analysis of system installation faults. That RLDU is not firmly connected makes the average RSSI in the sector of the base station very low.

8.2.4 Radio Frequency (RF) Components and Some Installation Faults

RSSI monitoring fuction consists of the monitoring of host bus adapter RSSI and that of diversity RSSI. For a common ± 45ºdual polarization antenna, the host bus adapter/ diversity difference of RSSI is generally less than 3dB. If the average level of host bus adapter/diversity exceeds 6dB, it shows that the host bus adapter and diversity are unbalanced in receiving. There may be three factors lead to a great performance difference in the host bus adapter/diversity receiving RSSI. 1) There exists self-excitation fault in the equipment antenna feeder part. It can be seen from equipment structure that the host bus adapter/diversity of the equipment are unrelated, therefore there is little possibility of simultaneous self-excitation in both poles. Great difference in the host bus adapter/diversity RSSI shows that it is possible that self-excitation occurs to a single pole only. 2) A dual-polarization antenna has some problems with unipolar receiving. If there may be some faults in antenna polarization receiving, it may lead to abnormal receiving power of the host bus adapter/diversity RSSI with great difference. 3) Poor unipolar connection in equipment installation. The host bus adapter and diversity in the equipment are unrelated to each other. If unipolar receiving is not well installed, it will also lead to

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RSSI abnormality. For example, the unipolar feeder connector is not well connected. Installation faults are commonly found in RSSI abnormality.

The following figure typically shows poor unipolar installation connections. The difference is around 10dB between the host bus adapter and diversity one. It is found that some feeder connector gets loose.

8.3

8.3.1

Using YBT250 for Interference Locating and Analysis

When conducting electromagnetic background tests or seaching the interference source in a locating network, we generally use YBT250 for interference tests.

For details of using YBT250, please refer to YBT250 Operation Manual

For interference analysis guide, please refer to Guide to ETS450D Interference Fault Troubleshooting

Criteria for Interference Judgment

Judgment of reverse interference:

The 1.6MHz in-band total power which deviates from the central frequency by -800KHz ~ +800KHz does not exceed -100dBm.

Judgment of forward interference:

The 1.8MHz in-band total power which deviates from the central frequency by -900KHz ~ +900KHz does not exceed -100dBm.

With actual conditions taken into account, we may adjust the threshold to -95dBm based on the deduction in the RSSI part.

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8.3.2

1)

2)

3)

Common Steps for Interference Tests

According to the features of mobile communication, forward link interference needs to be tested in the whole coverage area; while reverse link interference needs only to be tested where antennas are installed. Observe Noise Floor in the interference test window after YBT250 has been settle down. According to the judgment criteria, it shows that the interference exists if there is any narrowband interference pulse found greater than -90dBm and it apparently higher than the background noise level within the tested frequency band. In this case, go to the spectrum test window. From the very beginning, you may set a small spectrum SPAN, for example, 2MHz, to watch whether there is any interference signal. If no interference signal is found, you may gradually increase the spectrum SPAN to view interference signals. Sometimes the interference source frequency is far away from the CDMA frequency band and its harmonic waves may induce certain interference in the CDMA system.

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Guide to CDMA Network Optimization Chapter 9 Common Methods of Locating and Troubleshooting

Equipment Faults

52

Chapter 9

9.1

Common Methods of Locating and

Troubleshooting Equipment Faults

During network optimization, some common equipment faults need to be eliminated. Introduced here are some common methods of locating and troubleshooting equipment faults on the site.

Methods of Locating Faults in Message Tracing Equipment

When network fault occurs, onsite network optimization engineers should first be able to find out to where the fault belongs, that is, whether the problem is on the MSC side, on the BSC side, on the BTS side or it is a network optimization fault. Any equipment fault should be accurately located to clarify that the fault does not lie in the network optimization part.

Chapter 7 details the methods of signaling tracing. According to the signaling flow, an analysis of signaling traced is made here to provide the method of locating where network fault occurs according to signaling tracing analysis.

First, make an analysis of the basic call signaling flow in the CDMA system. The call flow of CDMA is shown below:

Calling MS Calling BTS Calling BSC


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53

During the calling, a mobile phone first initiates a call and the originating call signaling is sent to BTS, BTS tranfers this signal to BSC, and the BSC sends a service request to MSC. If MSC resource application is normal, MSC will send a CAM back to BSC. Upon receiving the CAM, BSC begins to apply for allocation of BSC resource. If the BSC resource allocation has been completed, BSC will send a CAM to the mobile phone. Thus, the mobile phone is normally accessed and sends a successful service connection message to BSC. Now the call setup has been completed.

There are three equipment resource application processes actually being seen during the signaling process: the BTS & Abis resource application, the BSC resource application, and the A interface & MSC resource application. Therefore, in actual network operation processes, the often occurred equipment faults can be divided into three parts. Thus, the calling process in locating and troubleshooting equipment faults can also be divided into 3 parts.

Part 1: Whether a base station can normally receive a call origination message: If the base station normally receives the call origination message from a mobile phone, and this message can be normally sent to BSC, it shows that the base station and the Abis interface work normally. On the contrary, if a message tracing console cannot trace the call origination message of a mobile phone during the dialing process, it shows that the fault must lie in the base station, or its transmission, or the air interface part. For the air interface part, we need to be concerned about local coverage and interference. If all these are normal, the fault must lie in the base station or the transmission.

Part 2: Whether a BSC can normally receives the assignment request messages sent from the MSC: Upon receiving any call origination message sent from a base station, BSC sends a service request message and negotiates with MSC about necessary A interface circuit resource. Upon receiving the service negotiation message, the MSC implements corresponding authentication and MSC resource allocation. If the A interface becomes faulty, or there is erroneous MSC resource allocation, the assignment request timer of BSC will be timeout, or Layer 2 of MSC sends a connection release message. It appears that during the signaling process, the N-Disconnect message from MSC is directly received after CM has sent.

Part 3: Whether a BSC can allocate the BSC call resource normally: This process analysis may be divided into 2 parts: One is that when receiving a call origination message sent from a base station, BSC cannot correctly apply for CIC resource. The corresponding timer directly sends a release message to the mobile phone after its timeout. That is, during the signaling tracing, BSC has received OM and then sends Realse ord directly to an air interface instead of sending CM to MSC. The other is that upon receiving Assignment Message sent from MSC, BSC fails to apply for BSC


Equipment Faults

54

call resource. It appears that during the signaling tracing, BSC sends Realse ord to MSC and air interface upon receiving AM from MSC.

Shown below is a typical circuit fault in MSC A interface. It can be seen during the signaling tracing that after sending a CM message to MSC, BSC receives the N_DISCONNECT IND message that MSC has already sent, instead of receiving the assignment completion message from MSC.

After tracing and analyses of these messages, network faults can be directly located to MSC, A interface, BSC, Abis or BTS. When network faults have been successfully located, the results may be submitted to corresponding equipment experts for solutions.

9.2

9.2.1

Common Methods of Locating and Troubleshooting Equipment Faults on the Base Station Side in Network Planning & Network Optimization

During network optimization, network optimization engineers may often encounter faults related to base station equipment and Abis transmission links. Introduced here are some methods of locating and troubleshooting these faults.

Method of Locating & Analysis of Abis Interface Faults

Common Abis interface faults is disconnected transmission. The most effective method of locating this fault is as follows: First, use the Ping command directly to ping the IP address of the destination base station. If Request time out occurs during the process, it shows that there is poor transmission quality and packet loss or error code may occur. If Request time out occurs repeatedly and there is no fault in 8850 route configuration, it shows that there is interrupted transmission. The other simple


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55

9.2.2

9.2.3

way is to view base station alarms. If any intermittent disconnection occurs to transmission, two alarm messages (Abis link fault Alarm and MOT connect disconnect Alarm) may be seen in history alarms.

Transmission faults should be eliminated by specialized BSS engineers and what onsite network optimization engineers should do is to provide a corresponding fault-related analysis report.

Methods of Locating & Troubleshooting Baseband Processing Board Faults in Base Station

The baseband processing boards in a base station include the interface module BCIM, clock integrated module BCKM, channel processing module BCPM, and resource processing module BRDM.

For the baseband processing board, the faults are mainly the incorrect board version and the abnormal board runnings. The two faults can be eliminated in the following two ways. As to an incorrect board version, you may use the dsp btsbrdver command to query a corresponding board version. If there is an inconsistent board version, an inspection report should be submitted to the corresponding BSS engineers for board upgrade. The running status of a board can be queried by means of the dsp btsbrdstat command. If its status is abnormal, an inspection report can also be submitted to corresponding BSS engineers for further processing.

For a clock integrated unit BCKM, you need to query GPS signal locking to make sure whether GPS works normally. If GPS channel locking is instable, handoff and call drop faults may appear in the network. For GPS satellite locking, you may use the DSP BTSBRDSPECSTAT command to query it. Normally, GPS should lock 7~8 satellites.

The common used methods of eliminating baseband frame faults are BCKM reset, onsite power failure reset or board plugging/unplugging. Note that these three methods may interrupt any service. Network optimization engineers should not perform related operations unless permitted by the project manager.

Locating & Troubleshooting of TRX and HPA Faults in Base Station

For TRX and HPA, signals go first from a low frequency to an intermediate frequency, then to a high frequency, and then are amplified. TRX and HPA play an important role in equipment and are apt to become faulty. This is mainly shown in whether a board works normally and whether the output power of a board is normal.

Consistent with a baseband processing board queries, you may query a board by typing dsp btsbrdstat command to make sure whether it works normally. If the board


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56

9.2.4

9.3

9.3.1

9.3.2

does not work normally, an inspection report should be submitted to corresponding BSS engineers for further processing.

In checking the output power of a board, we generally use the command str infotrace: brdtp=btrm, brdid=?, item="power" for query. The output result of this command is the digital power of TRX and HPA. Normally, these two boards have approximate powers with the difference less than 2dB, that is, the numeric value is around 38dBm without load. If there is a great difference in their powers or too small an output result in numeric value, it shows that some fault occurs to TRX and HPA.

When some fault occurs in TRX and HPA, slot swap-substitution tests are generally conducted on the site. If the fault remains the same, a board should be replaced.

Locating & Troubleshooting of CDU and Antenna Feeder Faults

The main function of CDU and antenna feeder is to send RF signals to the air interface. The fault analysis related to this part normally adopts the RSSI analysis means. For analysis details, please refer to Analysis of RSSI and Network Interference Locating in Part 2 of Chapter 8.

When any fault in CDU and antenna feeder is found, installation check is the main job to do. For a CDU fault, the common investigation means includes the slot swap-substitution tests.

Detailed Inspection of Equipment Board Faults in Base Station

During network optimization, common means of optimization as introduced previously may be used to locate and eliminate faults. To eliminate more difficult faults, however, the more detailed inspections & analyses should be made. This section introduces detailed inspections and troubleshooting methods, which are used as a reference in eliminating other faults.

Power Supply Check

Check whether the -48V DC input at the set top is normal. The normal range for voltage input should be -40V~-60V. Besides, the power indicator on the lightning protection indicator board of the power supply should be normally on and the lightning protection indicator should be normally off.

Transmission Link Check

Check whether BCIM works normally, whether the E1 trunk circuit is faulty, whether the XIE board in BSC is faulty, and whether BSC and OMC become faulty or are


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57

9.3.3

9.3.4

wrongly configured. For inspection process, please refer to the BCIM fault inspection steps in board faults.

Check of Received GPS Signals

GPS signals are first received by the GPS antenna feeder system and then delivered to BCKM, whose clock unit processes them.

Check whether OMLs between OMCs work normally; whether Abis links are normal; whether base station clocks run normally (antenna feeder system inspection, clock reference source configuration inspection, BCKM reset & replacement).

Check of Cabinet Parts

First check the PSU module of the power frame, then check the boards (including BCIM, BCKM, BCPM, BRDM, and BTRM), and finally check various RF parts (including BHPA, CDU, RLDU, and antenna feeder system) which form an RF path.

* Power supply check

Check whether the PSU module of the power shelf becomes faulty and whether -48V DC input at the set top is normal.

* Board check

Check BCIM and transmission links. A base station cannot establish normal connections with BSC only if these two parts work incorrectly.

Check BCKM and GPS received signals. Other boards in a base station can work normally only when these 2 parts work normally.

Check whether BCPM works normally.

Check whether BRDM works normally. BTRM can work normally only when BRDM works normally.

* Check of RF parts

Transmitting path: The signals from BTRM are first amplified in BHPA module and then sent to the CDU for multiplexing processing. Then, these signals are output to an antenna feeder, where they are transmitted.

Receiving path: RF signals are received by the antenna feeder system and sent to the CDU. Then, the RLDU divides the received signals and sends them to the corresponding BTRM modules for processing.

Check BHPA, CDU, RLDU, and the antenna feeder system according to the above mentioned transmitting/receiving path.


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9.3.5

1)

2)

Check of Control Interface Module (BCIM)

Faults: Unable to establish any operation & maintenance link with OMC, BOOTP request failure; O&M down, signaling down, or service link interrupted during the base station running, E1/IMA/UNI link alarm at the near end.

Analysis & problem locating:

Check if the transmission links between BCIM of the BTS and XIE board of the BSC are normal. For details, please refer to the BCIM fault inspection in board faults.

BCIM abnormality: When BCIM is powered on and initialized, the indicators RUN, ALM, and ACT are normally on. When OMU has been configured and is in service, the indicator RUN flashes at the frequency of 0.5Hz. If both the indicators ALM and ACT flash at the frequency of 4Hz, it shows that the communication link between a board and OMU becomes faulty. If only the communication link between this board and OMU becomes faulty, the fault may lie in this board. In this case, check whether this board is well plugged. If the communication links between other boards and OMU become faulty at the same time, it is possible that BCKM or baseband shelf backplane becomes faulty. In this case, check whether BCKM is well plugged and whether it runs correct software.

E1 trunk cable fault or connection error: E1 trunk cable fault or connection order error may be checked by means of E1 loopback tests. The configuration information and status of IMA/UNI may be obtained by querying the dedicated status of the board in a base station.

Interface board (XIE) fault of BSC: If E1 trunk cables are found normal and correct in order of connection when E1 loopback tests have been conducted, but the control interface board cannot listen to any configuration, it is possible that the interface board (XIE) of BSC becomes faulty. In this case, you may eliminate this fault by resetting or replacing XIE. BSC and OMC become faulty or are not configured correctly: At a far-end OMC client terminal or near-end maintenance console, you may query the dedicated status of a board to obtain the status of an IMA group or whether the UNI link is in normal status; check whether the BOOTP identification of the CMUX board of the BM shelf in BSC is configured correctly; check whether any routing information is correctly configured; check whether there is any error of related data of far-end OMC; check whether any far-end OMC becomes faulty, for example, the BAM loading or communication process is abnormal, BAM collapse, etc.


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9.3.6

1)

2)

3)

4)

9.3.7

1) 2)

Check of Main Control Clock Module (BCKM)

Faults: The links between OMC and OMLs of BTSs fail to be established; Abis link fails to be established; base station clock works abnormally; and other faults.

Analysis & fault locating:

If a base station succeeds in BOOTP request, but its OML link cannot be established correctly, BCKM in the base station will repeatedly initiate BOOTP requests. This continued for several minutes will cause the base station to reset. For detail, please refer to “Point 4 in Locating Control Interface Board Faults”. The Main Control (MC) unit of BCKM is responsible for the establishment of an Abis signaling link with BSC, but failed or some fault occurs to its running. Locating process: check whether the IMA group or UNI link works normally. For details, please refer to “Item 4 in Locating Control Interface Board Faults”; check whether the Abis signaling link configuration parameters are normally set up. The Abis signaling link adopts the mode of IPOA and needs to be configured with the following parameters: PVC parameters (VPI and VCI), TCP/IP address (IP address, subnet mask, and TCP port No.) of Abis signaling link. In addition, we still have to make sure whether the PVC used by the Abis signaling link does differ from that used by the Abis service; also check whether BSC becomes faulty. A base station clock does not work normally: Eliminate the antenna feeder system fault, check the configuration of the clock reference source, reset BCKM, and replace BCKM. Other faults: The faults in main cabinet power module, baseband shelf fan module. Note that the main cabinet environment monitoring is also reported to BCKM and it may be included in other faults. If the fan module of a baseband shelf becomes faulty, you need to replace the module; if the main cabinet power module becomes faulty, refer to Elimination of PSU Faults for how to process.

Check of Channel Processing Module (BCPM)

Faults: BCPM clock error; abnormal reverse data with BRDM service links; FPGA status error; internal error of channel processing chip or clock error; board hardware module error.


BCPM clock error: Refer to BCKM Fault Locating. Abnormal reverse data between BRDM and BCPM service links: For reverse data errors of gigabit Ethernet links, you need to check whether BRDM connected with the BCPM by a backplane works normally, refer to BRDM Fault Locating for details. At the same time, eliminate any baseband shelf backplane fault.


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3)

4)

9.3.8

1)

2)

3)

4)

9.3.9

1)

FPGA status error: Reload FPGA software. If the fault still exists, replace the original board. Other faults: Reset BCPM. If the fault still exists, replace the original board.

Check Resource Distribution Module (BRDM)

Faults: FPGA status fault; fault in links communication with BTRM bottom layer; clock signal fault; board hardware fault.


FPGA status fault

For FPGA status fault, reload FPGA software. If the fault still exists, the fault lies in board- related hardware and you have to replace the board. Communication link faults at BRDM and BTRM bottom layer are generally because communication links have too great an error rate, or a board does not work normally. You may try pluging/unpluging fiber or replace BTRM; if this fault has existed for a long time, you may reset it, or even replace this BRDM.

Clock signal abnormality fault

The clock necessary for BRDM control service switching comes from BCKM. If BCKM does not work normally, this fault may happen. First, check whether BCKM phase locking is normal. If yes, you may attempt to load FPGA logic. If the fault still exists after all the above measures have been taken, it shows the fault lies in hardware and you need to replace this BRDM. BRDM hardware fault: Generally because of bad components or erroneous loaded logic. If this is the case, you need to replace the board.

Check of Transceiver Module BTRM

Faults: Receive path over-excitation; software phase out-of-lock; abnormal forward link power; reverse link signal strength indication abnormality alarm; RS485 link fault alarm. Other BTRM faults: Transmitting path clock out-of-lock, hardware phase-locked loop out-of-lock, I0 value abnormality, and digital down converter fault. RF fan module faults: The fan monitor & control board fails to read temperature sensor; fan runs abnormally; fan monitor & control board temperature alarm; the fan speed control of the fan monitor & control board becomes invalid. BTRM becomes less sensitive.


Receive path over-excitation

If the interference leads to receive path over-excitation, try to reduce as much external interference as possible, instead of doing anything on base station.

If any FPGA logic fault leads to receive path over-excitation, reset or replace BTRM.


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2)

3)

4)

5)

6)

7)

Software phase out-of-lock: If the fault is not caused by hardware fault, it will automatically recover within 5 minutes. If this fault exists for a long time, you may perform the following procedures:

Eliminate a corresponding BRDM fault.

Then, replace corresponding fibers.

Replace this BTRM.

Abnormal forward link power: This may interfere adjacent cells:

Check whether BRDM, BCPM, or BCKM has been unplugged. If the fault is caused by these, no treatment is necessary.

Replace corresponding fibers.

Eliminate the faults in BRDM, BCPM, and BCKM.

Replace this BTRM.

Reverse signal strength indication abnormality alarm: Abnormal reverse signal strength may lead to interrupted reverse service links and you need to check the antenna feeder system. RS485 link fault

RS485 link faults will make any alarm information about the fan monitor & control board unable to be reported to BTRM and closed loop power control invalid. Troubleshooting procedures:

Reinstall a corresponding BHPA after power-off, and then power it on again.

Replace the fan monitor & control board (or a corresponding RF fan module).

Replace the BTRM.

Replace the RF backplane.

Other faults:

Transmitting path clock out-of-lock, hardware phase locking loop out-of-lock, I0 value abnormality, and digital down converter fault.

If these faults occur, and the fault still cannot be eliminated after BTRM is reset, replace the corresponding BTRM.

RF fan module faults:

A fan monitor & control board fails to read the temperature sensor; the fan stop runs abnormally; the fan monitor & control board temperature alarm; the fan speed control of a fan monitor & control board becomes invalid.

Troubleshooting procedures are as follows. If the fault still exists after a step has been taken, go to the next step.


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9.3.10

1)

2)

Check whether the fan helmet is connected in a correct, stable way.

Replace the fan monitor & control board or a corresponding RF fan module.

Check of High Power Amplifier (BHPA)

Faults: No RF signal output; abnormal RF signal output, including low output power and excessive spectrum output;


1. No RF signal output: Mainly because of self-protective shutdown, self-damage, and abnormal connection of cables or connectors.

Self-protective shutdown: For the sake of self-protection, a BHPA will automatically shut down in the case of any power amplification alarm and excess temperature.

(a) Power amplifier over-excitation alarm

Power amplifier over-excitation alarm reflects the level of BHPA RF input signals. If the level of RF signals input is between +0.5dBm and +1.5dBm, BHPA will generate an over-excitation alarm, but will not shut down automatically; when the level of the RF signals input is greater than +2.5dBm, BHPA will generate an over-excitation alarm and automatically shut down. If external alarm conditions no long exist, BHPA will be back to normal.

(b) Power amplifier excess temperature alarm

Power amplifier excess temperature alarm reflects the temperature rise of the power amplification base plate. If any power amplifier excess temperature alarm occurs, BHPA will automatically shut down. If the power amplifier temperature is 95ºC ± 5ºC, BHPA will generate an excess temperature alarm and shut down automatically. The recovery threshold of the excess temperature is 80ºC ± 5ºC.

Query the current alarm of a base station at OMC or a near-end maintenance console of BTS to make sure whether there exists any “power amplifier over-excitation or excess temperature” alarm.

Troubleshooting procedures:

Check whether the RF output power of BTRM is too high. If yes, decrease the output power of BTRM.

Check whether the corresponding fan of BHPA works normally.

Check whether there are normal cable connections between the power amplifier within BHPA and RF fan monitor & control board.

Abnormal connection of cables/connectors


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3)

BHPA adopts a blind-match connector and is connected by means of a backplane with BTRM, CDU, and power supply. Any input/output connection abnormality may lead to no RF signal output from BHPA.


Plug and unplug BHPA to make sure that BHPA adopts correct blind match and is normally connected with a backplane;

Check the backplane to see whether there is any loosening of connection cables between BTRM and BHPA, between BHPA and CDU, and between the power supply and BHPA;

Self-damaged

If BHPA is checked and found to have normal power supply, normal connections of cables and connectors, and normal signal inputs, but there is no RF signal output from BHPA, BHPA is considerable damaged and need to be replaced.

2. Abnormal RF signal output

Abnormal BHPA RF output signal means that the output power is lower than the rated power or the Adjacent Channel Power Ratio (ACPR) of output signals is excessive. Fault causes: Decreases of power amplification gains; some power amplification components are damaged; excessive output power. In the case of gain decreases, a corresponding alarm will be generated. Too high an input or an output power will lead to diffusion of spectrum output from a power amplifier and excessive ACPR.

A power amplification gain decrease alarm reflects the working status of BHPA amplification path. Alarm threshold range: Decrease in gains by 3~6dB. If the gain of BHPA decreases by more than 6dB, a gain decrease alarm will be generated; if the gain of BHPA decreases within 3dB, no gain decrease alarm be generated; if the gain of BHPA decreases by the value between 3 and 6dB, it is considered normal whether a gain decrease alarm will be generated or not.

Query the current alarm of a base station at OMC or a near-end maintenance console of BTS to make sure whether there exists any “power amplifier gain decrease” alarm.


Check whether there is too high an output power from BHPA. If yes, switch down the output power of BHPA.

Replace BHPA.


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9.3.11

1)

2)

9.3.12

1)

2)

3)

Check of Receiving Line Divider Unit (RLDU)

Faults: Antenna standing wave alarm; RLDU fault


Antenna standing wave alarm

The antenna standing wave alarm in a sector reflects the mismatch information of an antenna feeder system. If any antenna fault leads to stronger antenna standing wave, or an antenna is not normally connected with a feeder, an antenna standing wave alarm will be generated in a sector.


Check whether antenna feeder connection and antenna are normal;

Check whether CDU works normally;

Check whether there are normal cable connections between CDU and RLDU;

Check whether the power indicator on the RLDU panel works normally;

Replace RLDU.

RLDU fault

If any RLDU fault alarm is generated, you need to replace the faulty RLDU.

Check of Power Supply Unit (PSU)

Faults: The PSU does not work at all or does work abnormally; PSU fan fault; PSU output over-voltage fault; PSU input under-voltage fault; PSU overheat fault.


PSU does not work or does not work normally

If none of the 3 indicators on the PSU panel is on or any of them flashes, it shows that PSU is not in normal status and some unknown fault occurs within it. In this case, you need to replace the PSU.

PSU fan fault

If the PSU fan appears faulty while running, the alarm indicator (Alm) on the PSU panel will be on and the fan fault alarm will be reported at the same time. In this case, you need to replace this PSU fan.

PSU output over-voltage fault

If PSU output is higher than 30.5 ± 0.5V, PSU will automatically shut down and stop running. The alarm indicator (Alm) on the PSU panel will be on and the output over-voltage fault alarm will be reported at the same time. This fault status cannot be recovered automatically and you need to replace this PSU.


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4)

5)

9.3.13

PSU input under-voltage fault

If the input voltage of PSU is lower than 36.5 ±1V, PSU will stop outputting any power. The alarm indicator (Alm) on the PSU panel will be on and the input under-voltage fault alarm will be reported at the same time. If the voltage input is higher than 38.5 ±1V, PSU will automatically resume to normal.

PSU overheat fault

If the ambient temperature of PSU is excessively high or the heat sink system does not work normally, the temperature within PSU may be too high and PSU will stop outputting any power. The alarm indicator (Alm) on the PSU panel will be on and an overheat fault alarm will be generated at the same time. If its internal temperature decreases to a certain extent, PSU will automatically resume to normal.

If the ambient temperature is normal and the PSU fan runs normally, but PSU is continuously overheated, this module will be considered faulty and should be replaced.

Check of RF Antenna Feeder Part

Faults: Standing wave alarm; there is no transmitting power or too low a transmitting power at the antenna-air interface;


If this fault occurs, you may check first the standing wave and transmitting power (including the power tested at the coupling output interface of CDU) at the antenna-air interface of CDU and then those of the antenna terminal in a base station. Meanwhile, check whether connectors are installed correctly and firmly, and whether there is any loosening or breaking off of seal adhesive. Detailed procedures of troubleshooting:

Water penetrates the antenna feeder system.

The antenna, feeder, or jumper is damaged (For example, short circuit or open circuit).

The antenna and jumper in a base station are open-circuited or in poor contact.

The jumper and feeder are open-circuited or in poor contact.

The jumper and connector at the set top are open-circuited or in poor contact.

The jumper within a cabinet and CDU are open-circuited or in poor contact.

The feeder or jumper connector is not correctly installed on the site.


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9.3.14

9.4

Check of Satellite Antenna Feeder Part

Faults: Antenna open circuit alarm; antenna short circuit alarm


If this fault occurs, you need to check whether various connectors are correctly installed or tightened, and whether there is any loosening or breaking off of seal adhesive. Detailed procedures of troubleshooting:

Water penetrates the satellite antenna feeder system.

The satellite antenna, feeder or jumper is damaged (For example, short circuit or open circuit).

The lightning arrester for a satellite antenna feeder is damaged.

The satellite antenna and jumper are open-circuited or in poor contact.

The jumper and feeder are open-circuited or in poor contact.

The jumper and connector at the set top are open-circuited or in poor contact.

The jumper within a cabinet and the SMA connector on the BCKM panel are open-circuited or in poor contact.

The SMA connector on the BCKM panel and the GPS receiving card are open-circuited or in poor contact.


Overseas operators, if not in a large scale, usually have no good transmission equipment and the equipment room may be not in good conditions. Hence their antenna feeders maybe not well installed. Among their equipment faults are Abis transmission interruption fault and antenna feeder installation fault. In onsite optimization, the 1st important job is to check and analyze carefully the transmission alarms and RSSI tracing results in a base station to acquire a full knowledge of rough network quality and to eliminate any existing faults in transmission and installation. Based on this, we should conduct further Drive Tests and make an analysis of traffic statistics, or implement network optimization at a higher level.

Sheet1

Data Rate Destination FER

1X 1%

2X 2%

4X 2%

8X 3%

16X 5%

Documents

CDMA2000 Handbook for Onsite Optimization-20071021-B-1.0

Sheet1