5 NodeB Troubleshooting

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NodeB Troubleshooting

V100R007

HUAWEI TECHNOLOGIES CO., LTD. Page 2All rights reserved

References

《 RAN Troubleshooting Cases》

SUPPORT.HUAWEI.COM


Upon completion of this course, you will be able to:

Know how to find NodeB faults

Grasp NodeB troubleshooting methods

Know how to prevent NodeB faults.


Chapter 1 General IntroductionChapter 1 General Introduction

Chapter 2 Typical CasesChapter 2 Typical Cases

Chapter 3 NodeB Fault PreventionChapter 3 NodeB Fault Prevention


General Introduction

Alarm

Alarm console

Alarm box

OMC Shell

Traffic statistics

Drive test

Routine inspection

Customer complain

The ways to find faults The ways to find faults


Locating faulty equipments

If RNC has fault, usually it will affect some Sites or all of Sites

If NodeB has fault, usually it just affect itself and the handover successful rate of adjacent cells

During implementation or expansion, we can “Interchange ” NodeB and judge the fault is because of RNC or NodeB

During maintenance, RNC faults don’t just affect one NodeB




RAN fault

Cell

Traffic

Link

Interconnection

Clock

Antenna & Feeder

transmission

Operation and maintenance fault

OMC

Software LoadingRNO fault

Access

Call drop

Congestion

Handover

Common fault typesCommon fault types



Analyzing the Alarm Information

Alarm information come from the RAN alarm system, indicated usually through sound, light, LED, and screen output, etc

It includes the detailed description of the abnormality, possible causes and restoration suggestions, involves the hardware, link, trunk and CPU loading ratio, etc.. It is a gist for the fault analysis and location

Analyzing the Indicator Status

Indicators can indicate the work status of circuit, link, optical path, node and active/standby mode besides that of the corresponding boards, usually used along with the alarm information generally

Analyzing Traffic Statistics Result

It is the most useful method for locating RNO fault.

Basic Basic troubleshootingtroubleshooting method methodss



Analyzing Apparatus & Meter Test Result

It reflects the fault nature with the visual and quantified data

Some common Apparatus & Meter

− Signaling Analyzer, Test phone, Sitemaster, etc.

Tracing the Interface

It is applied in locating the failure causes of subscriber call connection and inter-office signaling cooperation, etc.

The trace result can help to find the cause of call failure directly and locate the problem or to get the index for the subsequent analysis

Traffic Test

It is a simple and quick method to judge whether the call processing function and relative modules of the RAN are normal or not




Comparison/Interchange Comparison: compare the faulted components or phenomenon with the

normal ones, and find the differences so as to find the problem

− It is usually used in the situation with simple fault range Interchange: if the fault can not be located even after the standby

components are replaced, you can interchange the normal components (such as board, optical fiber, etc.) with the potential faulted components, and to compare the work status so as to specify the fault range or part

− It is usually used in the situation with complicated fault range Switching/Resetting

It can not locate the fault cause accurately, and due to the randomness of software running, the fault may be not able to recur, thus it is difficult to know the real fault and solve the problem

This method is just an emergency method, applicable only in the emergent situation




Contacting the Technical Support Engineers of Huawei

Before you call, please collect information as follow

Detailed name of the office or site

Linkman and telephone

Time of fault occurring

Software version of the office or site

Detailed description of fault

Alarm files, interface tracing files, traffic statistic result

Actions performed after the fault’s occurring and the results

Problem level and the time you wish to solve the problem

Basic Basic troubleshooting troubleshooting methodmethodss


Summary General Procedures of Troubleshooting

Finding fault－ >Judging Fault－ >locating fault－ >Removing Fault

Basic Methods of Fault Judgement and Location

For simple fault

− Analyzing the Alarm Information and the Indicator status

− Comparison/Interchange

For complex fault

− Analyzing Traffic Statistics Result

− Analyzing Apparatus and Meter Test Result

− Tracing the Interface, Traffic Test

For restoring system

− Switching/Resetting







2.1 Transmission Faults2.1 Transmission Faults

2.22.2 Operation and Maintenance Operation and Maintenance FaultsFaults

2.3 Cell Faults2.3 Cell Faults


Transmission Faults RAN Transport Network

RAN transport network

2.5G/ 622M/ 155M

2M/34M

PDH

155M

155M

NodeB

Microwave

NodeB

RNCRNC NodeB

NodeB NodeB

NodeB

NodeB

NodeB

OptiX

NodeB

OptiXOptiX

OptiX

OptiX

NodeB

DSL

NodeBNodeB

NodeBLMDS

Synchronal network


Transmission Broken

− Transmission device, board or E1 is faulty

▪ More transmission device, more fault

− Transmission code is different (use CRC4 or not)

High BER (bit error rate)

− Microwave, HDSL transmission, especially in rainy weather

− E1 connection quality is bad

▪ It will cause bad quality, even transmission broken

− The grounding system is faulty

Transmission FaultsPhenomena and CausesPhenomena and Causes


Case1: E1 Broken (to be continued )Transmission Faults

Description E1 broken,E1 having alarm

Troubleshooting methods This could be due to interface board faulty, E1 port faulty or E1

cable faulty 1. Check for alarm on the board and E1 port

DSP BRDDSP E1T1If board is faulty, then replace board

2. Board not faulty, but E1 port having alarm. Perform loop back test on local endSET E1T1LOP ( Loopback Type = LOCAL )LOP E1T1 （ RNC ）DSP E1T1 （ NodeB ）SET E1T1LOP ( Loopback Type = NOLOOP) If E1 port is faulty, then replace board


TXRX

RXTXRNC NodeB

Step 2: Local Loop Back>> SET E1T1LOP (Loop type=local)>> DSP E1T1

Step 2: Local Loop Back>> SET E1T1LOP (Loop type=local)>> LOP E1T1 (Activate loop)>> SET E1T1LOP (Loop type=noloop)

Step 3: Remote Loopback>> DSP E1T1

Step 3: Remote Loopback>> SET E1T1LOP (Loop type=remote)

Step 1: Check Board and ports>> DSP BRD >> DSP E1T1

Step 1: Check Board and ports>> DSP BRD >> DSP E1T1

Case1: E1 Broken (continued) Transmission Faults

Troubleshooting methods

3. Board not faulty, E1 port not fault ,but alarm being in existence then perform loop back on far end and monitor at RNC

SET E1T1LOP (Loop type=remote)

DSP E1T1 （ RNC ） If transport network is fault, then examine cable and devic

e

Transport network







Operation and Maintenance System Faults

NodeB provides two modes of operation and maintenance

− Near end operation and maintenance

− Far end operation and maintenance

Fundamental Knowledge

RNC

SNTP Server

M2000

Subnet 2 Subnet 3

IPoA local IP

IPoA Peer IP

RNC BAM IP

Subnet 5

Subnet 4

LMT 2

LMT1

Subnet 1

BTS3812E

NMPT EthernetPort IP address


Case1: Downloading Software Package Lasts Too Long,Sometimes Software Downloading Fails


Description

In the course of software upgrading, it takes several hours to download the software package, and sometimes, the software downloading procedure fails


Case1: Downloading Software Package Lasts Too Long, Sometimes Software Downloading Fails



For maintenance over IPoA through RNC, check whether the IPoA bandwidth on RNC Operation and Maintenance system is too narrow

Increase the IPoA bandwidth to speed up software downloading progress based on the actual situation.


Case2: Fail to Log in to NodeB by Near End ModeOperation and Maintenance System Faults

Description

In near end maintenance mode, the Operation and Maintenance system can log in to NodeB normally before downloading data configuration file. When NodeB restarts after the data configuration file downloading procedure finishes, the Operation and Maintenance system cannot log in to NodeB by near end mode, but can log in to it over IPoA. In this case, board indicators are normal.


Case2: Fail to Log in to NodeB by Near End ModeOperation and Maintenance System Faults


The reason for this fault may be incorrect setting of IP address of near end maintenance channel

− Step 1: Log in to NodeB over IPoA link through Operation and Maintenance system, configure IP for near end maintenance channel by using the MML command SET IP. Query whether the setting is successful by using the MML command LST IP.

− Step 2: Open the data configuration file on the configuration management system to modify the NodeB property. Modify the local IP address as the value demanded, download the data configuration file again, and then restart the NodeB.







Cell FaultsFundamental Fundamental KnowledgeKnowledge

NBAP_AUDIT_REQ

NBAP_CELL_SETUP_REQ

NBAP_CELL_SETUP_RSP

NBAP_COMM_TRANSP_CH_SETUP_REQ

NBAP_COMM_TRANSP_CH_SETUP_RSP

NBAP_SYS_INFO_UPDATE_REQ

NBAP_SYS_INFO_UPDATE_RSP

NBAP_AUDIT_RSP

NodeB RNC


Case1: No CELL SETUP REQUEST Message from RNC While NodeB in Normal State

Cell Faults

Description

The logical cell cannot be setup. When you perform query with MML command on NodeB Operation and Maintenance system, the local cell resources are available, and both NCP and CCP states are normal. Upon receipt the request of resource audit from NodeB Operation and Maintenance system by MML command ADT RES, RNC delivers only a resource audit command but no CELL SETUP REQUEST message


Cell Faults


Check whether the maximum downlink power reported by NodeB in the audit message is smaller than the value configured by RNC.

On NodeB Operation and Maintenance system, use the MML command DSP CELL to view whether the local cell ID is consistent with that specified in RNC

Case1: No CELL SETUP REQUEST Message from RNC While NodeB in Normal State


Case2: Cell Deleted and Setup Repeatedly, RNC Multi-Frame Out-of-Synchronization Alarm Occurs, Cell Setup Fails

Cell Faults

Description

From the message traced by Iub interface, cell is deleted and setup repeatedly. At the same time, there are multi-frame out-of-synchronization alarms unable to be cleared in RNC. But E1 cable state is available when queried by the MML command DSP E1T1 on NodeB Operation and Maintenance system


Case2: Cell Deleted and Setup Repeatedly, RNC Multi-Frame Out-of-Synchronization Alarm Occurs, Cell Setup Fails

Cell Faults


The most possible cause for this fault is that E1 working mode for NodeB is not consistent with that for RNC: dual-frame for NodeB, and multi-frame for RNC.


Case3: Only One Cell Can Be Setup due to Modification of Cell Radius

Cell Faults

Description

Originally, cell 0 and cell 2 can be setup normally. After the radius of both cell 0 and cell 2 is modified from 256*78 m to 1536*78 m, cell 2 is failed to setup. The local cell is unavailable due to lack of baseband resources according to the query result with the corresponding MML command.


Case3: Only One Cell Can Be Setup due to Modification of Cell Radius

Cell Faults


The fault must be caused by lack of access resources. A set of access resources includes an access ASIC and an access DSP. When the cell radius is smaller than or equal to 384*78 m, a set of access resources can support three cells. When the cell radius is greater than 384*78 m, it can support only one cell.


Case4: RNC Deletes Cell after NodeB Responds with Cell and Common Transport Channel SetupCell Faults

Description

RNC sends a CELL SETUP REQUEST message to NodeB, and NodeB reports a CELL SETUP RESPONSE message to RNC. Then RNC sends two COMMON TRANSPORT CHANNEL SETUP REQUEST messages. Upon receipt of the two COMMON TRANSPORT CHANNEL SETUP RESPONSE messages from NodeB, the RNC sends a CELL DELETION REQUEST message instead of a SYSTEM INFORMATION UPDATE REQUEST message. There is no alarm in NodeB or RNC


Case4: RNC Deletes Cell after NodeB Responds with Cell and Common Transport Channel SetupCell Faults


The fault may be relative to Iub interface user plane. In this case, it is necessary to check the user plane of NodeB and RNC in data configuration and hardware connection to see whether they are consistent.






NodeB Fault Prevention


NodeB Fault Prevention Hardware: installation specifications are most important

Pay more attention to E1 connector Pay more attention to feeder connector Pay more attention to the waterproofer of antenna and feeder

system Confirm the grounding and lightning protection

Checking Running status NodeB maintenance console

− First, do “multi-site fault query”,

− Then, try to remove the fault according to the alarm description and suggestion

− If you cannot remove the fault provisionally, confirm the reason of every fault at least

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5 NodeB Troubleshooting