02-Fault Analysis and Location

8/11/2019 02-Fault Analysis and Location

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Maintenance ManualM900/M1800 BTS3X Series Base Transceiver Station Table of Contents

Huawei Technologies Proprietary

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Table of Contents

Chapter 3 Communication Fault.................................................................................................. 3-1

3.1 Introduction to MS's Search for the Network ..................................................................... 3-1

3.2 Call Failure......................................................................................................................... 3-2

3.2.1 Fault Description ..................................................................................................... 3-2

3.2.2 Fault Analysis and Location .................................................................................... 3-2

3.2.3 Troubleshooting Procedure..................................................................................... 3-3

3.3 No Voice Heard after the Call is Connected...................................................................... 3-5


3.3.2 Fault Analysis and Location .................................................................................... 3-5 3.3.3 Troubleshooting Procedure..................................................................................... 3-6

3.4 Unidirectional Talk ............................................................................................................. 3-6




3.5 Poor Voice Quality ............................................................................................................. 3-7




3.6 Conversation Interruption .................................................................................................. 3-8




3.7 Cross Talk.......................................................................................................................... 3-9




3.8 Mobile Station Frequently Disconnected from the Network .............................................. 3-9

3.8.1 Fault Description ..................................................................................................... 3-9 3.8.2 Fault Analysis and Location .................................................................................... 3-9

3.8.3 Troubleshooting Procedure................................................................................... 3-10

3.9 Immediate Assignment Rejection .................................................................................... 3-10

3.9.1 Fault Description ................................................................................................... 3-10

3.9.2 Fault Analysis and Location .................................................................................. 3-10


Chapter 4 Network Fault ............................................................................................................... 4-1

4.1 Mobile Station Fails to Find a Network.............................................................................. 4-1






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4.1.4 Clearing Hardware Problem.................................................................................... 4-2

4.2 Mobile Station Fails to Access the Network ...................................................................... 4-3




4.3 MS Frequent Location Updating........................................................................................ 4-5




Chapter 5 Loading Fault ............................................................................................................... 5-1

5.1 Software Loading Failure................................................................................................... 5-1


5.1.2 Introduction to Software Loading ............................................................................ 5-1



5.2 Base Station Initialization Failure....................................................................................... 5-4


5.2.2 Introduction to Base Station Initialization ................................................................ 5-4



5.3 Signaling Fault ................................................................................................................... 5-5 5.3.1 Fault Description ..................................................................................................... 5-5

5.3.2 Introduction to OML................................................................................................. 5-5



5.4 RSL Link Blocked............................................................................................................... 5-6


5.4.2 Introduction to RSL Link.......................................................................................... 5-6



Chapter 6 Antenna and Feeder System Fault............................................................................. 6-1

6.1 Fault Description................................................................................................................ 6-1

6.2 Introduction to the Antenna and Feeder System............................................................... 6-1

6.3 Fault Analysis and Location............................................................................................... 6-1

6.4 Troubleshooting Procedure ............................................................................................... 6-1

6.4.1 Poor downlink signal ............................................................................................... 6-1

6.4.2 Unstable downlink signal......................................................................................... 6-2

6.4.3 Poor uplink signal.................................................................................................... 6-2





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Chapter 7 Optical Channel Fault.................................................................................................. 7-1

7.1 Fault Description................................................................................................................ 7-1

7.2 Fault Analysis and Location............................................................................................... 7-1

7.3 Troubleshooting Procedure ............................................................................................... 7-1

Chapter 8 Board Fault................................................................................................................... 8-1

8.1 TMU ................................................................................................................................... 8-1

8.1.1 Sources of Fault Information................................................................................... 8-1

8.1.2 Related Functional Units ......................................................................................... 8-1

8.1.3 Fault Classification.................................................................................................. 8-1


8.2 CDU ................................................................................................................................... 8-4




8.3 EDU ................................................................................................................................... 8-7




8.4 SCU ................................................................................................................................. 8-10

8.4.1 Sources of Fault Information................................................................................. 8-10

8.4.2 Fault Classification ................................................................................................ 8-10


8.5 TRX.................................................................................................................................. 8-12 8.5.1 Sources of Fault Information................................................................................. 8-12



8.6 PBU.................................................................................................................................. 8-15




8.7 PMU ................................................................................................................................. 8-17


8.7.2 Related Functional Units ....................................................................................... 8-17



8.8 PSU.................................................................................................................................. 8-21




8.9 TEU.................................................................................................................................. 8-23


8.9.2 Related Functional Units ....................................................................................... 8-23





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8.10 TES ................................................................................................................................ 8-24

8.10.1 Sources of Fault Information ............................................................................... 8-24

8.10.2 Related Functional Units ..................................................................................... 8-25

8.10.3 Fault Classification.............................................................................................. 8-25

8.10.4 Troubleshooting Procedure................................................................................. 8-25



Maintenance ManualM900/M1800 BTS3X Series Base Transceiver Station Chapter 3 Communication Fault


3-1

Chapter 3 Communication Fault

3.1 Introduction to MS's Search for the Network

Mobile Station (MS) may operate either in the HPLMN (Home Public Land Mobile

Network), or in other PLMNs. There are two modes for a mobile station to select the

serving network:

Automatic network search

Manual network search

After a mobile station (with a SIM card or after a SIM card is inserted) is powered on,

the mobile station searches for the PLMN it logged in last time. If the PLMN does

exist, the mobile station attempts to log in.

If the login succeeds, the mobile station will be served by this PLMN.

If the login fails because no appropriate cell is available, the mobile station will

search at least thirty 900M channels or forty 1900M channels (The process of

searching the radio frequency channels actually includes the selection of PLMN).

If the login fails due to the failure of location updating, then it is unnecessary to

select the above mentioned frequency channels. However, the available PLMNs

must be displayed to the subscriber. Subscribers can then select network inautomatic or manual mode.

In automatic network search mode, the mobile station selects the network according

to the priority of PLMN list it has saved. While in manual mode, the mobile station

displays the available networks to the subscriber and tries to log in to the specified

PLMN according to the subscriber's selection.

Network search may be affected by the roaming process of the mobile station. This

process can be classified into two types: international roaming and domestic roaming.

International roaming: in which the mobile station logs in to other PLMNs in a differentcountry from where the HPLMN is located.

Domestic roaming: in which the mobile station logs in to other PLMNs in the same

country where the HPLMN is located in. When the mobile station is roaming across

the country, it will search for a HPLMN periodically. To prevent a mobile station from

logging in frequently to a prohibited Location Area (LA) during domestic roaming, the

mobile station saves this LA in a table named ‘‘Forbidden Las for domestic roaming’’

of the mobile station equipment. This table will be cleared when the mobile station is

powered off or when the SIM card is pulled out.





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In addition, the mobile station saves in its own SIM card some of the PLMNs where

services are prohibited. Only when these PLMNs are selected in the manual network

search mode and the location updating succeeds can these PLMNs be deleted from

the service-prohibited PLMN table.Failure of mobile station network search indicates the failure in selecting a PLMN or a

cell.

3.2 Call Failure

3.2.1 Fault Description

When the mobile station is powered on and detects a network, the following occur

after subscriber dial-up:

No ringing at the called MS after dialing though that MS is idle.

After dialing, the caller hears the ring-back tone, but the call is automatically

disconnected.

After dialing, the caller hears the ring-back tone, but the call is automatically

disconnected when the called answers.

3.2.2 Fault Analysis and Location

The failure of an MS in originating calls might be related to the fault of BTS, BSC,MSC or the PSTN.





3-3

3.2.3 Troubleshooting Procedure

No

Yes

No

YesNo

Yes

No

Yes ANo

B

Yes

Start

Check Abis interface

Immediateassignment

Assignmentis over

Radio linkfails

Check the measurement

SDCCHavailable?

TCHFavailable?

Re-configure or increasethe cell capacity

Check the setting of paging parameter

Check Abis interfacedata mapping relationship

Re-configure or increasethe cell capacity

report





3-4

Receiving qualityis too poor

B

Yes

Possible causes:1. Improper BTS connection

2. Poor TMU clock precision3. Too much air interference4. BSC clock is not accurate enough

5. Problems with antenna and feeder system

No route at network sideYes

Possible causes:

2. TC board abnormal3. A-interface blocked4. MSC unable to obtain the No. Of roaming subscribers

5. Some routes are blocked at MSC side

No

1. Wrong connection of BSC switching

No

Other causes

Possible causes:

End

TC board program abnormal

A

Figure 3-1 Troubleshooting procedures for call failure

To clear the faults in originating calls, follow the instructions below:

Trace and check Abis interface message via the interface in BSC maintenance

console.

1) If the immediate assignment fails, check if any assignment failed because

SDCCHs are insufficient.

Y The cell capacity is not large enough. In this case, re-configuyre or expand

the cell capacity. N The failure of immediate assignment may be caused by data configuration

errors. In this case, check the setting of paging parameters of the cell at the data

management console.

2) If instead of immediate assignment failure there is TCH assignment failure,

check whether the TCHs are insufficient.

Y Check Abis interface data mapping relationship at the data management

console.

N The cell capacity is not large enough. In this case, re-configure or expand

the cell capacity.





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3) If the radio link failure occurs after the TCH channel is established, observe the

measurement report on the channel before the failure.

Poor quality of BTS or MS signals may be the result of the following factors:

Improper BTS connection Low TMU clock precision

Too much air interference

BSC clock not accurate enough

Problems with the antenna and feeder system

Blind spots in network coverage

4) The causes for absence of route at network side that causes the disconnection

of links may be:

Connection error of BSC switching network

Abnormality of TC board

Blocking of A-interface

Failure of MSC in get roaming subscriber number

Blocking of some routes at MSC side

3.3 No Voice Heard after the Call is Connected


There is ringing at the called mobile station, but no voice is heard when the called

subscriber answers to the call.


The ringing at the called mobile station indicates that the signaling flow is normal. The

voice generation failure may be related to multiple aspects (not sure):

The failure of corresponding timeslots of TC board, which is the only place where

the voice can be converted from voice signals of 16K into that of 64K.

Switching network failure, which disables proper switching of voice timeslots.

Activation failure of DTX voice transmission.

Call re-establishment failure, which causes the signaling course being switched

over before the time specified in data configuration, but the switching circuit did

not receive the indication of change properly, therefore, the circuit failed to react

to the change.

Abnormality of TMU board.





3-6


1) Check the occupation of network board timeslots to see whether the network is

distributed correctly, i.e., check whether both TCHs have been switched over

correctly.

2) Switch off the DTX to see whether the phenomenon reappears.

3) Check signaling analyzer or Abis signaling interface tracing through BSC

maintenance console to see whether there are any messages about call

re-establishment failure.

4) Reset TMU board to see whether the phenomenon reappears.

5) If the phenomenon persists, there may be erroneous switching at the fixed

network side.

6) Plug in/pull out or replace TC board to see whether the phenomenon reappears.

7) If not, it is the board that fails.

3.4 Unidirectional Talk


Mobile station can make calls, but:

When both the two parties use an MS for conversation, one of them cannot hear

the other.

When one of the two parties uses an MS and the other a fixed phone forconversation, one of them cannot hear the other.


Judging from that one of the two parties can hear the other, the signaling flow is

normal.

Then, this fault may be caused by:

Mobile phone transmitter fault.

Activation failure of DTX voice transmission. GNET board switching error, which disables the up-link of one party from being

switched properly to the down-link circuit of the other party.

Some links on TC Board are blocked.


1) Does this occur repeatedly to some MSs? If so, the transmitter function of the

mobile station may be faulty.

2) Switch off the DTX to see whether the fault still exists.





3-7

3) View the occupation status of GNET board timeslots to see whether the circuits

are switched normally by querying GNET board status on BSC maintenance

console.

4) Trace and query the circuit status at MSC. If some circuit ports are alwaysdisconnected, block the port or replace TC board.

5) Check if there is any public network faults.

3.5 Poor Voice Quality


The mobile station can detect a network after it is powered on, and can make/receive

calls, but the voice quality is poor.


If the mobile station can make calls, the signaling channels are normal.

Poor voice quality indicates that the voice BER (Bit Error Ratio) at the radio interface

is high. Generally, the high BER during decoding at the base station is caused by low

receiving level or degrading of clock precision.


1) Check the signal intensity at the mobile station. Low signal intensity indicates

that the receiving level is too low. Try to communicate in an open place.

2) Ask the peer party to check whether the battery of the mobile station is low.

3) Determine whether the fault is related to the TRX or any timeslots of it. If yes,

reset or replace the TRX.

4) Check the measurement reports by an MS with the signaling analyzer or by

tracing Abis interface at the BSC maintenance console to determine whether it is

up-link level or down-link level that is poor.

If the up-link level is poor, please check whether the power supply of the MS issufficient.

If the down-link level is poor, the fault may be caused by the coverage. In this

case, check whether the radio frequency is degrading or whether the subscriber

is at the edge of a cell.

5) If the receiving level is OK but BER is high, the fault may be caused by the

instability of the clock. In this case, try to relocate the network by measuring the

precision of BTS, BSC clocks.

6) If both the receiving level and BER are OK, check the interference on the

transmission links between BSC and BTS.





3-8

7) Check antenna and feeder system.

3.6 Conversation Interruption


Conversation interruption during the normal process of a conversation of a mobile

station refers to the fact that there is no voice heard for a while, or the voice is

intermittent.


Conversation interruption possibly results from the degrading of environment or

equipment performance, and may also be caused by faults of BTS, BSC, MSC or

PSTN.


The fact that the voice is intermittent during the conversation indicates that the

speech channel has been established and kept in service. But there may be some

break points in the link, which hinders the normal transmission of the voice to the

receiving end and causes conversation interruption. The following may be related to

the causes of break points in this link and suggested solutions are also provided ifpossible.

1) If the TC board is abnormal, reset it (or replace it if necessary). High BER at

network side and BTS side may be the result of low precision of BSC or BTS

clock, or the interference between transmission links.

2) TRX sensitivity is too low,.Handling suggestion: Replace TRX.

3) Co-frequency interference among cells. Handling suggestion: reconfigure cell

data.

4) The receiving antenna and feeder are abnormal. Handling suggestion: check

whether there are water-penetration, corrosion or short-circuit with the receivingantenna and feeder.

5) Check whether the mobile station is located too far away from the BTS, or in

blind area.

6) Fixed network equipment is abnormal.





3-9

3.7 Cross Talk


The voice from another channel is heard in the course of normal conversation of the

mobile station.


Cross talk is most possibly caused by switching error, i.e., the signals of another

speech channel are switched to the current conversation timeslot. As a result, the

subscriber affected may either hear the voice from the ongoing conversation among

some other subscribers, hear nothing at all, or cannot be heard by the other partyengaged in the conversation with him.


1) Check GNET board networking to see whether there is any missing or duplicated

networking.

2) Check the switching of timeslots at the switch side. Fault of this switching is

common in fixed network.

3.8 Mobile Station Frequently Disconnected from theNetwork


When the MS is idle, it happens frequently that the MS sometimes display the

network it accessed and sometimes not, indicating that the MS is frequently

disconnected from the network.

The MS is frequently disconnected from the network while in the course of

communication.


When the MS receives system message and calculates the parameters such as C1, it

finds that the cell where it is located no longer meets the requirements of the

protocols. Besides, no other cells are detected appropriate. In this case, the mobile

station disconnects from the network.





3-10


1) Check whether the system message is sent properly, whether the reselected

parameters of the cell and the parameters of random access control changes

frequently.

2) Check with the tester MS whether the value of C1 displayed on the MS is too

small. If yes, check whether the parameters that may affect the value of C1 are

set properly, such as MS RXLEV_ACCESS_MIN, MS maximum transmission

power allowable, etc. Check the up-link and down-link receiving levels to see

whether the MS is located in an area of poor coverage.

3) Check whether the BTS output is stable. If not, check whether the TRX output is

normal or whether the antenna is fixed in a stable manner.

3.9 Immediate Assignment Rejection


From Abis interface, it can be observed that immediate assignment rejection message

is sent on CCCH channel in the course of SDCCH channels assigning.


No SDCCH channel is available for the assignment.


1) Check whether BSC data configuration is correct, such as radio channel

configuration table, and so on.

2) Observe at BTS maintenance console whether SDCCH channels are blocked or

whether they are available. Unblock them if they are in ‘BLOCKED’ state.



Maintenance ManualM900/M1800 BTS3X Series Base Transceiver Station Chapter 4 Network Fault


4-1

Chapter 4 Network Fault

4.1 Mobile Station Fails to Find a Network


The message ‘No Network’ is displayed at the MS.

There is no display at the MS at all.

There is no home PLMN in the network list displayed at the MS.


I. The cell is not in service

At the BTS maintenance console, select [Obtain Cell Attributes] to view the

information of the corresponding cell.

If it is prompted that ‘Cell is not initialized’, the cell then is not in service.

If the information on the corresponding cell is displayed, the cell then is already

in service.

II. Trace Abis interface message flow and observe whether there is anychannel request

If no channel request is detected to be directed to this cell, either the network or the

individual MS may be faulty.

1) The causes of network fault may be:

BS hardware problem

At the BTS maintenance console, check whether the operating status or the status

indicators of respective boards are normal. Check if the attributes of TRX and TMUboards are consistent with the data configuration of the data management console,

and whether the BSC clock is locked by the clock board. If all these items are normal,

test whether the power output of the antenna and feeder is normal.

Incorrect system message

Check whether the configurations of CI, LAI, BSIC and CCCH are consistent with

those in the radio channel configuration table.

2) The causes of individual MS is fault may be:





4-2

The MS is not located in a suitable place and RXQUAL (signal quality) is poor or

RXLEV (signal level) is too low. Move the MS to an open place and try again.

The battery of the MS is low.


If the cell is not in service, reset the site hierarchically. Please note that this may affect

the other cells under this site. During the initialization, the progress of the initialization

will be displayed. Base station initialization is embodied by the initialization of site and

cell.

I. Site Initialization Procedure:

1) Set site logic object

2) Set site hardware object3) Set site extended attributes

4) Establish multi-point connection

5) Site activation

II. Cell Initialization Procedure:

1) Create TEI

2) Establish signaling channel connection

3) Establish traffic channel connection

4) Set cell attributes5) Set cell extended attributes

6) Set RC attributes

7) Set RC extended attributes

8) Set channel attributes

9) Set cell alarm threshold

10) Cell activation

11) Wait for cell status change report

The result of these two types of initialization will be displayed at the maintenance

console on a realtime basis.

If the operation succeeds, a solid star will be displayed.

If the operation fails, a hollow star together with the cause of failure will be

displayed.

4.1.4 Clearing Hardware Problem

If the system messages are wrong, correct them. Set the whole table and validate

them with the help of dynamic data configuration.





4-3

4.2 Mobile Station Fails to Access the Network


The MS displays ‘No Services’ or ‘Only Emergence Call’, or does not display

anything at all.

One or more networks are detected when manual searching of networks is

performed.

From Abis interface, no message can be observed or ‘Location Updating

Rejection’ is observed.

The indicator of OML link of LAPD board flashes quickly or is off.

The indicator of RSL link of LAPD board flashes quickly or is off.


No SIM card is installed. Please insert a SIM card.

The battery of the MS is low. Please recharge the battery.

The cell is not in service. For details, refer to ” 4.2.3 Troubleshooting

Procedure ”.

If RSL is disconnected, the indicator of RSL link on LAPD board flashes quickly

or is off. For details, refer to ‘4 Signaling Fault’ of this module.

If OML is disconnected, the indicator of OML link on LAPD board blinks quickly

or is off. For details, refer to ‘4 Signaling Fault’ of this module.

System message is incorrect.

If a dual-band MS is forcedly set as a single band 1800M (or 900M) MS, then it

can not access the 900M network (or 1800M network).

If some internal settings of the MS are improperly modified, the MS may fail to

access the network.


If the cell is not in service, then perform level-4 resetting to the site and check

whether the initialization flow is normal. 1) Is the cell activated?

Y Refer to step 3) below.

N Refer to step 2) below.

To judge whether the cell has been activated:

Select [Obtain Cell Attributes] to view for the information of the corresponding cell at

the base station maintenance console. If it is prompted ‘Cell is not initialized’, the cell

has not been activated. If attribute information about the cell is displayed, the cell has

already been in service.





4-4

2) For the cell that has not been activated, reset the site that the cell belongs to.

Please note that this will affect the conversation of other cells under the site.

During the initialization, the progress indication of respective stages of the

initialization will be displayed.

Base station initialization is embodied by the initialization of site and cell.

Site initialization procedures:

Set site logic object

Set site hardware object

Set site extended attributes

Establish multi-point connection

Site activation

Cell initialization procedures:

Create TEI

Establish signaling channel connection

Create traffic channel connection

Set cell attributes

Set cell extended attributes

Set RC attributes

Set RC extended attributes

Set channel attributes

Set cell alarm threshold Cell activation

Wait for the cell status change report

The result of these two types of initialization will be displayed at the maintenance

console in real time. If the operation succeeds, a solid star will be displayed. If the

operation fails, a hollow star along with the causes of failure will be displayed.

If there is any data error in the initialization, check the corresponding data

configuration.

If the initialization can not be executed, there is a configuration error in the board

corresponding to the main control board of the base station. Check the boardand return to Step 1).

3) If the cell has already been in service, check whether the clock signal of the cell

and TRX board corresponding to BCCH are normal. If they are not, please take

corresponding measures.

How to check:

Select [Equipment Status Query] at the maintenance console to view the board

status.





4-5

If the icon of the board is red, the board is abnormal. In this case, check whether

the hardware of the base station, the communication between TRX and TMU,

and whether each board is normally powered on.

4) If the MS is a dual band one, but forcedly set to single band mode, change backinto dual band mode.

5) If the MS is improperly set, restore the ex-factory default setting.

4.3 MS Frequent Location Updating


When powered on, the MS can locate the network and make/receive calls. But the

voice quality is poor because the MS updates its location frequently.


Location update of an MS takes place when:

It is moved into a new location area.

It is time for a regular location update.

It is powered on.

Frequent location updating usually results from improper data configuration.


1) Check the interface signaling. If ‘Normal location updating’, then the MS may be

located on the edge of a boundary area where multiple location areas are

overlapped (which is a rare case). Please try to move the MS forward to any

direction.

2) If the interface message ‘IMSI ATTACH’ appears frequently, and the MS is not

powered on and off frequently, check whether the MS RXLEV is so low that the

MS fails to receive base station messages and is thus disconnected from the

network.3) If frequent MS location updating is periodical, then the system message may be

abnormal and the location updating period may be set too short. Please check

whether the MS receives system message (T3212) correctly. Modify the value of

T3212 in the system message.

4) Check if the location area codes in different system messages are consistent .



Maintenance ManualM900/M1800 BTS3X Series Base Transceiver Station Chapter 5 Loading Fault


5-1

Chapter 5 Loading Fault

5.1 Software Loading Failure


If software fails to be loaded to the base station, and the interface does not prompt on

the successful completion of software loading, it indicates that the software of the new

version is not loaded to the base station.

5.1.2 Introduction to Software Loading

In BTS software loading, the specified software is loaded to the base station through

a remote maintenance console or the local MMI to upgrade the software of the base

station.

Files that can be loaded and activated are the ones named in the format of *.bin. The

loading of TRX software is actually the loading of 7 files that are bundled together.

TMU uses OM software.

The interface of software loading is shown in Figure 5-1 .

Figure 5-1 [SW Download] interface





5-2

In this interface, set all items of the software to be loaded, including file name,

sending window size, version, and file ID (file type), and then click <Begin> to start

the loading

Caution:

The software loaded will not take effect until it is activated.

Interface description:

1) File ID

File ID is the identifier of various types of board software of the base station. Software

No. varies with the types of boards. The file ID must match with the software.

TRX_MAIN is the running software for TRX, and TMU_MAIN that of TMU.

2) Version

Version is the Identifier the software of different versions for the same type of boards.

3) File Name

The path and file name of the file loaded.

4) Send Window Size

Send window size decide the number of frames of the messages sent by TMU

between two responses. Generally it can be set as 49.

After the software is successfully loaded, the interface of software loading will be as

shown in Figure 5-2 . The prompt ‘Load SW successfully’ will be displayed in the

message bar at the bottom of the interface [SW Download] .

If the loading does not proceed as described above, it is not successful.





5-3

Figure 5-2 Load SW successfully


1) Check the channel for the software loading.

If the software is loaded via a local MMI, check whether the serial port

connection is normal.

If the software is loaded via a remote maintenance console, check whether thenetwork connection is normal, and whether E1 line connection is correct.

2) Check whether the management authority is correct.

If it is loaded at a local end, the management authority should be obtained at the

local end.

If it is loaded remotely, the management authority should be released at the local

end.

3) Confirm whether the selection of software type is correct. For example, if the

loaded software is TRX software, but the selected software type is not

TRX_MAIN, then the loading will fail.

4) Check whether the data configuration meets the requirement of the version. Ifdoes not meet, the loading will fail.

5) Check whether every parameter is set correct, especially when use the remote

maintenance console, whether the software configuration description table is

correct (Please refer to “M900/M1800 Base Transceiver Station (BTS3X)

Software Installation”). If the software path in the “Software filename” is incorrect,

the loading will fail.





5-4


1) Make sure that the line connection is normal.

2) Make sure that the management authority is correctly set.

3) Make sure that the loaded software matches the selected type.

4) Make sure that the version No. of the loaded software is correct.

5.2 Base Station Initialization Failure


Base station initialization cannot be normally completed.

5.2.2 Introduction to Base Station Initialization

Base station initialization is embodied by the initialization of site and cell.

Site initialization procedures

1) Set site logic object

2) Set site hardware object

3) Set site extended attributes

4) Establish multi-point connection

5) Site activation

Cell initialization procedures

1) Create TEI

2) Establish signaling channel connection

3) Establish traffic channel connection

4) Set cell attributes

5) Set cell extended attributes

6) Set RC attributes

7) Set RC extended attributes

8) Set channel attributes

9) Set cell alarm threshold

10) Cell activation

Corresponding commands or data configuration is sent to the base station during

different stages of the initialization.


For site initialization error, check the corresponding data configuration, the TMU

board and the maintenance link.





5-5

For cell initialization error, check the corresponding data configuration, the TMU board,

the maintenance link and the corresponding board.

Check if the bit error rate on the transmission cable is too high or if there is any

transmission fault.


1) Check the corresponding data configuration step by step according to the

erroneous initialization. Correct errors if there is any.

2) Check if the corresponding boards and the maintenance links are normal.

Listed below is an explanation of the prompts on initialization errors:

‘Data configuration error’ and ‘Message does not match the physical

configuration’: there are errors in the data configuration of BSC datamanagement console. Please check the corresponding data configuration.

‘Communication timeout’: BTS does not respond within the specified time. After

this prompt appears, BSC will re-send the message. If the fault repeats, the

transmission link between BSC and BTS is disconnected or a fatal error has

occurred to the TMU of BTS.

‘Message structure error’, ‘Message type error’, ‘Illegal object type’,

‘Unsupported object type’, ‘BTS No. error’, ‘TRX No. error’, ‘Illegal attribute ID’,

‘Unsupported attribute’, and ‘Parameter exceeds the boundary’: there are errors

with the commands sent by BSC, which may be caused by BSC fault. The

problem ‘Parameter exceeds the boundary’ may possibly be caused by incorrect

data configuration.

5.3 Signaling Fault


While querying the corresponding maintenance link from BSC maintenance console,

it is detected that the signaling link status corresponding to OML link is not in

multi-frame link-setup state.

5.3.2 Introduction to OML

OML link is the link for maintenance message between BSC and BTS.


1) Check the status of the corresponding link.

2) Check whether the corresponding data configuration is correct.





5-6

3) Check whether the corresponding LAPD board is in normal position.

4) Check whether the BIE board of BSC are in normal position, whether the

corresponding E1 line and HW line are well connected, whether the status of the

corresponding E1 port of BIE board is normal.

5) Check whether the status of TMU board of the base station is normal.


1) If the corresponding OML link is in ‘TEI unallocated’ status, first check whether

the corresponding data configuration is correct.

2) Check whether the corresponding data configuration is correct and consistent

with hardware configuration.

3) Check whether LAPD board is in normal position.

4) Check whether the corresponding BIE board status is correct, and whether HWline and E1 line of the board are connected properly. If the corresponding E1 port

status is abnormal, HW line or E1 line might be wrongly connected.

5) Check whether the status of BIE board of the base station is correct.

5.4 RSL Link Blocked


While querying the corresponding signaling link via the BSC maintenance console, it

is detected that the link is not in multi-frame link-setup state.

5.4.2 Introduction to RSL Link

RSL link is the channel for signaling message between TRX and BSC.


1) Check the status of the corresponding signaling link. If it is not in multi-frame

link-setup state, specify what status it is in. 2) Check whether the corresponding data configuration of the link is correct.

3) Check the BIE board of BSC to see whether the corresponding E1 line and HW

line are well connected, and whether their status is normal.

4) Check whether the status of TMU board of BTS is normal.

5) Check whether the software of the cell is activated.

6) Check whether TRX board works normally.

7) Check whether the attributes of TRX are correct.

8) Check whether the DIP switch settings of the TMU, CMB, TRB and TDU are

correct.





5-7


1) If links are in ‘TEI unallocated’ status, check whether the data of the

corresponding link are configured correctly.

2) If the link is in disconnected status, please check whether the data of the

corresponding link matches the configuration of the hardware. If not, adjust either

the data configuration or the hardware configuration to make them match.

3) Check the status of the BIE board of BSC. Check whether E1 line and HW line

are well connected. If not, please connect them properly, and then recheck

whether the corresponding status recovers normal.

4) Check whether the corresponding LAPD board is in right location, and whether

its status is normal, and whether other links have been established.

5) Check whether TMU board status to see if it is normal.

6) Check whether the software of the cell is activated, whether it is in normalrunning.

7) Make sure that TRX is inserted in a proper slot.

8) Check whether the connector on the BTS cabinet top is well inserted.



Maintenance ManualM900/M1800 BTS3X Series Base Transceiver Station Chapter 6 Antenna and Feeder System Fault


6-1

Chapter 6 Antenna and Feeder System Fault

6.1 Fault Description

Small coverage

Reduced coverage

Signal fluctuation

Poor conversation quality

High ratio of dropped calls

6.2 Introduction to the Antenna and Feeder System

The antenna and feeder system is used to provide duplex radio channels between

MS and BTS.

A radio channel from BTS to MS is defined as a downlink channel, while one from MS

to BTS an uplink channel.

6.3 Fault Analysis and Location

Poor downlink signal

Unstable downlink signal

Poor uplink signal

Note that the distribution of interference band can be viewed at the traffic

measurement console using the menu command “TCH performance measurement”.

6.4 Troubleshooting Procedure

6.4.1 Poor downlink signal

1) Check whether the output of TRX OUT port on TRX module (including power

amplifier) is normal. If not, replace TRX module.

2) Check whether the output of TX/RX_ANT port on CDU module is normal. If not,

replace the CDU

Note:

Make sure that the transmission cable between TRX and CDU is normal.



Maintenance ManualM900/M1800 BTS3X Series Base Transceiver Station Chapter 6 Antenna and Feeder System Fault


6-2

Caution:

The prerequisite to the above procedures is that the transmission cable from TRX to

CDU is not faulty.

3) Test the antenna VSWR (voltage standing wave ratio) from 1/4” jumper

connector connected with TX/RX_ANT port of CDU module. If it is normal, check

the pitch angle of the antenna and adjust it to an appropriate angle.

4) If the VSWR at testing antenna end, tested from 1/4’’ jumper connector, is

abnormal, check section by section the VSWRs of respective connection ports of

the connecting cable (including tower-top amplifier, lightning arrester) between

this port and the transmitting antenna till the causes that worsen the VSWR arefound. The causes may be poor connection of connectors:

water leakage due to poor waterproofing of connectors

high VSWR of the antenna and feeder lightning arrester

high VSWR and water penetration of the antenna etc

Then take corresponding measures to clear the fault according to the different

causes.

6.4.2 Unstable downlink signal

1) Check whether the output (PA OUT port) of TRX module (including power

amplifier) is stable. If not, replace the TRX module.

2) Check whether the outdoor antenna and feeder system is reliable, and make

sure that the antenna and feeder do not sway with wind too much.

6.4.3 Poor uplink signal

1) Check whether CDU has tower-top amplifier alarm (TTA). If so, replace the

tower-top amplifier. CDU tower-top amplifier alarm can be obtained by viewing

the panel indicator and the alarm report from the operation and maintenance

console.

2) Check whether CDU LNA gives alarm. If so, replace the CDU module.

3) Check whether the connecting cable from input port TX/RX_ANT of CDU

antenna to the top of cabinet is normal. If not, replace the cable.

4) Test the VSWR of antenna and feeder from the top of the cabinet, the procedure

is the same as that in step 4 in I (Poor downlink signal).



Maintenance ManualM900/M1800 BTS3X Series Base Transceiver Station Chapter 7 Optical Channel Fault


7-1

Chapter 7 Optical Channel Fault

7.1 Fault Description

Optical channel alarm and transmission fault.

7.2 Fault Analysis and Location

This fault may be caused by:

Fault of the receiving and transmitting optical channel. Loss of 2M analog signals, 2M interface external clock or 2M line signals, or 2M

signal alarm.

Loss of 2M interface transmitting clock or 2M interface digital signals.

Fault of TEU-TES communication.

7.3 Troubleshooting Procedure

1) Check the optical channel between ASU and BSC.

2) Check the E1 wiring of ASU.

3) Check ASU board. 4) Check TES and TEU.



Maintenance ManualM900/M1800 BTS3X Series Base Transceiver Station Chapter 8 Board Fault


8-1

Chapter 8 Board Fault

8.1 TMU

8.1.1 Sources of Fault Information

TMU fault can be detected from the information gathered from:

The alarm box

The alarm console

TMU indicators

Hardware configuration status panel of the maintenance console

8.1.2 Related Functional Units

TRX, CDU, PSU, PMU, E1 lines.

8.1.3 Fault Classification

TMU fault may be caused by: No power supply

System alarm

E1 link alarm

Clock is in holdover or free-run mode

13M output clock is found to be inaccurate when tested with a frequency meter


I. Board power-off

In this case, the PWR power indicator on TMU board is off, the board does not work

and remote treatment becomes impossible.

1) Check whether PSU is switched on and whether VOUT indicator is on. If the

indicator is off, it means there is no PSU voltage output.

2) Check whether the TMU power switch in the switch box on top of the cabinet is

on.

3) Check whether the TMU is properly inserted and whether the power cable of the

backplane is well connected.





8-2

4) If the problem still exists, replace the TMU board.

II. System alarm

1) The remote maintenance console prompts on OML link faultFirst check whether CPU is normal, i.e., if the RUN indicator on TMU panel stops

flashing, CPU is abnormal.

If it is abnormal, replace the board and then check whether the E1 ports connected to

BSC are normal, i.e., if Indicators LI1, LI2, LI3 or LI4 on TMU panel are on or flashing,

it indicates that faults have occurred to the corresponding E1 ports.

If they are abnormal, refer to Section III 'E1 link alarm (including local alarm and

remote alarm)' to solve the problem and then check whether BSC data configuration

is correct.

If the problem still exists, replace the TMU.

2) The terminal maintenance console shows the fault of the boards or modules

other than TMU

First check whether the board reported to be faulty is really faulty.

Y Refer to relevant chapters or sections to solve the problem.

N There may be communication fault between TMU and this board. In this

case, solve the problem according to the following instructions:

Check BSC data configuration and the wiring of the backplane.

If the problem still exists, replace the TMU board or the board or module that is

reported to be faulty.

III. E1 link alarm (including local and remote alarm)

When some of the E1 ports are faulty, the line alarm indicators LI1, LI2, LI3 or LI4 on

the TMU board are on or flashing.

Fault of local E1 port is indicated with the above listed indicators on, while that of the

remote E1 ports, with these indicators flashing.

To clear this type of fault, first check whether data configuration and line connection

are correct.

For fault of local E1 port, check if the port reported to be faulty is configured and if the

E1 cables are connected.

For fault of E1 port that has been configured, connect the receiving and transmitting

terminals of the port with a 75 Ω coaxial cable to determine whether the board is faulty.

If alarm appears, it may be a TMU fault. Then replace the TMU board.





8-3

If the site is configured as in cascading mode, check the data configuration relative to

the cascaded sites.

IV. Clock is in free-run mode

In this case, the PLL indicator on TMU panel is on.

The clock enters free-run mode due to poor stability or loss of upper level clock

reference signal.

Check whether the configured clock reference source is introduced by the E1 link or

form the external clock.

1) If the clock reference signal is introduced by the E1 link, check whether there is

E1 link alarm.

Y Refer to Section III, 'E1 link alarm (including local alarm and remote alarm)'. N Test T2M clock on the panel.

If this clock is not very stable, there is fault with the upper level clock. Clear the fault

of the upper level clock and TMU will automatically switch to the locked mode.

2) If external clock is configured, check:

whether the wiring is correct

whether there is any external clock

whether the external clock, if any, meets the requirements

Clear the fault of the upper level clock and TMU will switch to the locked mode

automatically.

V. 13M output clock is found to be inaccurate when tested with a frequencymeter

Possible causes include:

Upper level clock is not accurate enough

TMU is damaged.

To clear this fault, check whether T2M signals on the TMU panel are faulty. If yes,

there is fault with the upper level clock. In this case, clear the upper level clock fault.

Correct the time of the upper level clock, and then:

1) Set the 13M output clock in free-run mode.

2) Send user-defined command to the 13M output clock to adjust the time of it.

3) Check if the 13M output clock returns to normal.

4) If the 13M output clock fails to lock the right frequency within (about) 20 minutes,

replace the TMU board.





8-4

8.2 CDU


TMU fault can be detected from the information gathered from:

The alarm box

The alarm console

CDU indicator status



High VSWR 1 (VSWR1) alarm

High VSWR 2 (VSWR2) alarm

Tower-top amplifier (TTA) alarm

Low noise amplifier (LNA) alarm


I. High standing wave ratio alarm 1 (VSWR1)

Check sequence: antenna system → CDU antenna port → CDU alarm .

1) Use a test mobile station to check if the antenna feeder system of the basestation can receive and transmit signals properly.

Y Manually reset the CDU and see whether the reported alarm is false. If yes,

proceed with Step 3).

N There might be fault with the antenna and feeder system. In this case,

proceed with Step 2).

2) Test the voltage standing wave ratio of the outdoor antenna feeder system.

Check if it is faulty, and determine whether replacement is necessary on the

parts of antenna feeder.

Below are the instructions on the testing of the outdoor antenna and feeder system: Shake the 1/4-inch jumper and 1/2-inch jumper connected with TX/RX_ANT port

of CDU, and see if their VSWR is stable.

Test the SWR at the 1/4-inch jumper connector connected with TX/RX_ANT port

of CDU, and shake the 1/4-inch jumper and the 1/2-inch jumper on top of the

cabinet to see if the VSWR changes noticeably.

When the VSWR is less than 1.3:1, the VSWR of the antenna feeder system is

regarded as normal. When the VSWR is greater than 1.4:1 or the cable is not

correctly connected, it is very probable that the antenna feeder system is faulty.

Try to replace the antenna feeder system to further determine whether the





8-5

system is faulty. If replacement does not help, go to Step 3). If this step shows

the antenna feeder system is faulty, please replace the antenna feeder system.

Caution:

If a tower top amplifier is installed on the feeder line, cut off its power feed and test if

the VSWR of CDU TX/RX_ANT port exceeds the standard by a large degree.

3) Check if CDU is faulty

Test if the VSWR of CDU TX/RX_ANT port is more than 1.5:1 which is seriously

in contravention of the standard. Check the VSWR alarm processing function of CDU: 1) Reset and re-power-on

CDU. In this case, the system should react like being restarted. Otherwise, CDU

is faulty. 2) Determine whether CDU is faulty by replacing it.

If CDU is found faulty, replace it.

4) If after Step 2) and Step 3) the cause of CDU VSWR alarm fault is not

determined, treat it as CDU VSWR alarm or as poor match between TX/RX_ANT

and the 1/4-inch jumper connector. In the former case, replace CDU. In the latter

case, replace CDU and the 1/4-inch jumper.

Note:

The cables from the 1/4-inch jumper to the antenna are connected in the following

manner:

The 1/4-inch jumper inside the cabinet 1) (N-type male connector to the 7/16 DIN

female connector on top of the cabinet)<===>1/2-inch jumper from the cabinet top to

the 2) (7/16 DIN male connector to 7/16 DIN female connector) <===>3) Lightning

arrestor (7/16 DIN female connector to 7/16 DIN male connector) <===> the feeder

line from the sealing window through wall to the triplex tower amplifier 4) (7/16 DIN

female connector to 7/16 DIN connector) <===> 1/2 jumper from the feeder line to thetriplex tower amplifier 5) (7/16 DIN male connector to 7/16 DIN male

connector)<===>triplex amplifier 6) (7/16 DIN female connector to 7/16 DIN female

connector) <===>1/2-inch jumper from triplex tower amplifier to the antenna 7) (7/16

DIN male connector to 7/16 DIN male connector)<===> antenna 8) (7/16 DIN female

connector).





8-6

II. High standing wave ratio alarm 2 (VSWR2)

Check sequence: antenna feeder system → CDU antenna port → CDU alarm .

1) CDU reports alarm to the TMU when VSWR2 occurs to it, and reports criticalVSWR2 alarm to the TMU if the alarm lasts for more than one minute.

2) After the TMU is informed of the VSWR2 alarm, it sends a command to the TRX

to switch off transmitting excitation.

3) Test if the reporting CDU has transmitting power.

Y TMU has not switched off the transmitting excitation. In this case, In this

case, go back to the last section "I. High standing wave ratio alarm 1 (VSWR1)"

and repeat step 1)-3).

N TMU has disabled transmitting excitation. In this case, repeat steps 2) and 3)

in the last section "I. High standing wave ratio alarm 1 (VSWR1)".

If the fault is not yet located at this point, enable TRX transmitting excitation and

repeat Step 1) of the last section "I. High standing wave ratio alarm 1 (VSWR1)".

4) Replace the CDU.

III. Tower-top Amplifier (TTA) Alarm

Check sequence: CDU → antenna feeder system (including tower top amplifier)

1) Reset CDU. Is the TTA alarm cleared after the resetting?

Y Proceed with Step 2).

N The reported CDU alarm is false. In this case, replace the CDU.2) Switch on the power supply to CDU tower top amplifier module. Does tower top

amplification occur to the CDU?

Y CDU voltage output is normal, and the alarm is caused by the insufficient

current of the TTA, which shuts down the voltage. In this case, the TTA is normal.

3) Disconnect CDU antenna port with the 1/4-inch jumper. Use a multimeter to

check if any short circuiting has occurred to the antenna feeder system;

Y The antenna feeder system is faulty. In this case, check the feeder line, jumper

and tower amplifier to locate the short circuit (such as water inflow).

4) Connect a galvanometer in series between the antenna port of the CDU and the1/4-inch jumper.

Keep the external conductor of CDU antenna port and the external conductor of the

1/4-inch jumper in good contact.

Switch on the power supply to the TTA and measure whether the voltage is 12V and

whether the power supply to the selected TTA is within the specified normal range. If

the voltage is normal but the current is zero, it indicates the TTA is in a state of

bypass. In this case, the TTA is damaged. Please replace it.





8-7

Note:

If Step 4) cannot be performed due to the limit of the actual conditions, replace this

CDU with one that does not comprise a TTA to check whether the antenna feeder

system is normal. Here are the procedures for the checking:

Power off this CDU, and disconnect the jumpers.

Connect the jumpers of the antenna feeder system to the antenna port of the CDU

that does not comprise a TTA.

Power on the new CDU and switch on the power supply to the TTA.

Is the new CDU reporting TTA alarm?

Y If any, it indicates that the tower amplifier is faulty.

5) Replace the TTA when it is confirmed to be faulty.

IV. Low noise amplifier (LNA) alarm

1) Test the gain from the testing coupling port to RX output port of this channel to

see whether it is normal. If not, replace the CDU.

2) Reset the CDU forcedly at the maintenance console. Does the CDU return to

normal after the resetting? Judge whether the software is faulty with the result of

the resetting.

3) After the CDU is confirmed to be faulty, replace it.

8.3 EDU


The fault of EDU can be detected with the information gathered from:

The alarm box

The alarm information at the alarm console

Status of EDU indicators

Hardware configuration status at the maintenance console panel


VSWRA alarm

VSWRB alarm

TTA alarm

LNA alarm





8-8


The faults are removed step by step. When one step fails to remove the fault, go to

the next step.

I. High standing wave ratio alarm A (VSWRA)

Check sequence: antenna feeder system fault, EDU antenna port fault or EDU false

alarm.

1) When VSWRA occurs to EDU, EDU will report the alarm to TMU. When this

alarm lasts one minute, CDU will report a critical SWR alarm to TMU; After the

TMU receives this report, it will automatically send a command to the TRX to

switch off transmitting excitation

2) Test to see if the said CDU has transmitting power. If not, go to Step 4); if so, (theTMU does not switch off transmitting excitation), got to Step 3).

3) Use a test mobile station to check if the antenna feeder system of the base

station can receive and transmit signals properly.

Y Check whether the reported alarm is false by manually resetting the CDU. If

the alarm is false, proceed with Step 5).

N There might be fault with the antenna feeder transmission system.

4) Test the standing wave ratio of the outdoor antenna feeder system to determine

whether it is faulty and whether parts of the antenna feeder system should be

replaced.

Below are the instructions:

Shake the 1/4-inch jumper and 1/2-inch jumper on top of the cabinet connected

with TX/RX_ANT port of EDU, and see if their VSWR is stable.

Test the VSWR at the 1/4-inch jumper connector connected with TX/RX_ANT

port of EDU, and shake the 1/4-inch jumper and the 1/2-inch jumper on top of the

cabinet to see if the VSWR changes noticeably.

When the VSWR is less than 1.3:1, the VSWR of the antenna feeder system is

regarded as normal. When the VSWR is greater than 1.4:1 or the cable is not

correctly connected, you may initially conclude that the antenna feeder system is

faulty. Adopt the method of antenna feeder system replacement to further make

sure if the system is faulty. When this method fails, go to Step 5). If this step

shows the antenna feeder system is faulty, please deal with fault in the way of

checking the fault of the antenna feeder system





8-9

Caution:

If a tower top amplifier is installed on the feeder line, its power feed must be cut off

first. Then, test if the SWR of EDU TX/RX_ANT port exceeds the standard by a large

degree.

5) Check if the EDU is faulty

Test to see if the VSWR of EDU TX/RX_ANT port is more than 1.5:1 beyond the

standard seriously.

When it is confirmed that the VSWR alarm processing function of EDU is abnormal,

first reset EDU and power on again. Does the system return to normal? Y If the alarm occurs again, the EDU is normal. If not, the EDU is faulty

Secondly, use EDU replacement method to make sure if the EDU is faulty.

Y Replace the EDU.

If the fault is not yet cleared at this point, switch on the TRX transmitting excitation,

and repeat Step 3) to make sure if the alarm is false.

6) If the EDU is found faulty, replace it.

II. Standing wave ratio alarm B (VSWRB)

Its removal process is the same as with the voltage standing wave alarm A.

III. Top-tower amplifier alarm (TTA)

Check sequence: CDU → antenna feeder system (including tower amplifier)

1) Reset EDU to see if the TTA alarm disappears. If not, a false alarm occurs to

EDU and it is necessary to replace the EDU. If the alarm disappears, go to Step

2).

2) Disconnect EDU antenna port with the 1/4-inch jumper. Use a multimeter to

check if short circuit occurs to the antenna feeder system; if so, it indicates theantenna feeder system is at fault, and it is necessary to check the feeder line,

jumper and tower amplifier to locate the short circuit (such as water inflow).

3) Switch on EDU TTA feeding power, and see if TTA alarm occurs to the EDU. If so,

it indicates that EDU voltage output is normal (the alarm arises from the shortage

alarm of TTA current, which shuts down the voltage. This is normal).

4) Connect a galvanometer in series between the antenna port of the EDU and the

1/4-inch jumper. Please be sure to keep good electric contact between the

external conductor of EDU antenna port and the external conductor of the

1/4-inch jumper. Switch on the feeding power of tower amplifier and measure





8-10

whether the feeding voltage is accurate (12V) and see if the current of the

feeding power of tower top amplifier stays within the normal work current range

of the tower amplifier selected. If the voltage is normal but the current is zero, it

indicates the tower top amplifier is in a state of bypass, the tower amplifier hasbeen damaged and thus requires replacing.

Note:

When the conditions for taking this step are not satisfied, an EDU without its tower top

amplifier working properly to check if the antenna feeder system that the EDU with

alarm fault corresponds to is normal: connect the jumper of this antenna feeder

system to the antenna port of the EDU that works properly (power off this EDU

beforehand, and disconnect the jumper as well), and power on EDU as well as the

tower top amplifier feeding (TCP), to see if the EDU tower top amplifier gives an

alarm. If any, it indicates that the tower amplifier is faulty.

5) Check each part of the antenna feeder system to locate the fault. If the tower top

amplifier is still faulty, replace it.

IV. Low noise amplifier alarm (LNA)

1) Test the gain from the testing coupling port to RX output port of this channel to

see whether it is normal. If not, replace the EDU.

2) Utilize the forced reset function of EDU alarm control unit.

3) Reset the EDU by force on the terminal maintenance console to check if EDU

indicator works properly. Thus, make sure if it is a software false alarm.

4) When EDU fault is located, replace the EDU.

8.4 SCU


Alarm box

View alarm console information


Downlink signals abnormal


Downlink signals not good

Transmitting power very small or the transmitting power of various channels

rather unbalanced





8-11

No transmitting power



the next step.

Note:

SCU module is a passive component, whose mean time between failures (MTBF) is

lengthy, and has no panel indicator. Furthermore, SCU needs to be used together

with CDU(not solely used at the front of base station RF). So, when fault occurs, it is

not easy to be noticed, and thus it is necessary to check carefully.

I. Downlink signals not good

1) First remove the fault, if any, of the RF cable between the antenna feeder system,

CDU module, TRX module, including TRX, SCU and CDU modules.

Use the wireless testing function of a test mobile station (configured with the base

station) to check whether the antenna feeder system of the base station can receive

and transmit signals properly. If the transmitting signals are intermittent or obviously

low, various CW of the same antenna are not balanced or signals are not through, it

indicates there might be something wrong with TRX transmission and the RF front

end, including the antenna feeder system.

First remove the fault, if any, of the RF cable between the antenna feeder system,

CDU module, TRX module, including TRX, SCU and CDU modules (for example,

the antenna is not installed, and the feeder line/jumper is not connected well).

If there is no fault, check if TRX transmitting power is normal.

In the event of any fault with TRX, CDU or the antenna feeder system, go to the

flow of dealing with fault with TRX, CDU and the antenna feeder system;

otherwise, go to the next step.

2) Test the transmitting insertion loss of SCU module and the return loss (SWR) of

each interface, to make sure if they are normal. If the transmitting insertion loss

of SCU (including any channel of the four) exceeds 7.1 dB, it indicates it's faulty;

if the interface return loss is less than 14 dB, it indicates SCU module is faulty.

3) When the above steps have been completed, if SCU is found faulty, please

replace the SCU module





8-12

II. Transmitting power very small or the transmitting power of variouschannels rather unbalanced

1) First check if the installation (connection) from TRX module to the outdoor

antenna feeder system is at fault, and if TRX module is abnormal. Check if the installation (collection) of the cable from TRX module to outdoor

antenna feeder system is faulty, so as to rule out the fault of cable damage or

installation fault

Check if TRX module has any alarm, and test to see if its transmitting power is

normal

2) Check CDU module and the parts of antenna feeder system such as feeder line,

lightning arrester, tower top amplifier and antenna. Refer to the process flow for

CDU fault and antenna feeder system fault for the processing.

3) When Step 2) fails to locate the fault, go to Step 2) in the section 'downlinksignals not good' for processing.

4) Replace SCU.

III. No transmitting power

1) First check if there is anything wrong with CDU module and TRX module.

When critical standing wave alarm occurs to CDU, BTS will switch off TRX

transmitting power

When standing wave alarm occurs to TRX, BTS will switch off TRX transmitting

power

2) Test to see if SCU combiner output port (TX-COM) is abnormal. If TRXtransmitting power is normal, use a spectrum analyzer (connected to high-power

attenuator of 60 dB) or power meter at the combiner output port (TX-COM) to

test if the output power of each TRX carrier wave connected with SCU is normal.

3) Replace SCU module.

8.5 TRX


Alarm box

Alarm console

TRX indicator status

Hardware configuration status panel of maintenance console


Over standing-wave alarm

Power alarm

Temperature alarm





8-13

Clock alarm

Phase-locked loop alarm

DSP alarm

Frequency hopping bus alarm

DBUS bus alarm

Power supply alarm

TRX no power output


The faults are cleared step by step. If one step alone can not clear the fault, go to the

next step.

I. High voltage standing wave ratio alarm1) Check the connecting cable between TRX and CDU. If there is poor contact or

any broken point, replace the cable.

2) Check whether the antenna is installed properly.

3) Replace the TRX if the fault still can not be removed.

II. Power alarm

Check whether there is power supply alarm.

Check whether there is any clock alarm and whether the clock line between

backplanes TRB and CMB is normal. Check whether TRX is firmly inserted.

Replace the TRX if the fault still can not be removed.

III. Temperature alarm

Check the cooling fan. Replace it if it stops running.

Check whether the ambient temperature is too high.

Replace the TRX if the fault still can not be removed.

IV. Clock alarm

Check whether TRX is in good contact with the backplane. Make sure that it is

firmly inserted.

Replace the TRX. If the problem still exists, replace the backplane.

If all TRXs of this cabinet give clock alarms, then go as follows:

Check whether the wiring is correct. If not, modify the wiring as required. Check

whether there is any broken line.

Check whether TDU module and the wire are properly connected and whether

there is any fault in TDU module. If there is, replace the TDU module.





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Check whether there is fault in TMU module. If there is, replace the TMU

module.

V. Phase-locked loop alarm

1) Check whether there is any clock alarm. If there is, refer to section IV, 'Clock

alarm', to solve the problem.

2) Check whether there is any power supply alarm. If there is, refer to section XI,

'Power supply alarm', to solve the problem.

3) Check whether the data configuration of this cell is consistent with the attributes

of this cell.

4) Replace the TRX if the fault still can not be removed.

VI. DSP alarm

1) Check whether there is any clock alarm. If there is, refer to section IV, 'Clockalarm', to solve the problem.

2) Check whether TRX is firmly inserted.

3) Check whether the indicators on TRX panel are flashing alternatively. If they stop

flashing or they are not on, reactivate TRX software or reset the TRX.

4) Replace TRX if the fault still can not be removed.

VII. FPGA alarm

1) Check clock alarm.

2) Reset TRX.3) Replace TRX if the fault still can not be removed.

VIII. FIFO alarm

1) Check whether there is any clock alarm. If there is, refer to section IV, 'Clock


2) Check whether TRX is firmly inserted.

3) Replace TRX.

IX. Frequency hopping bus alarm

1) Check whether there is any clock alarm. If there is, refer to section IV, 'Clockalarm', to solve the problem.

2) Check whether there is any DSP alarm. If there is, refer to section VI, 'DSP


3) Check whether there is any FPGA alarm. If there is, refer to section VII, 'FPGA



X. DBUS bus alarm

1) Check whether data configuration is correct and whether the cell is in service.





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2) Check whether the wiring is correct.

3) Check whether TMU module is in good contact with the backplane.

4) Check whether there is any fault in TMU module.

5) Check whether E1 line connection is proper.6) Check whether the TRX and the backplane are well connected.

7) Check whether TRX is inserted into the right slot.


XI. Power supply alarm

1) Check whether the power is switched off.

2) Check the backplane wiring.

3) Replace TRX.

XII. TRX no power output1) Check whether there is any clock alarm. If there is, refer to section IV, 'Clock


2) Check whether there is any phase lock loop alarm. If there is, refer to section V,

'Phase-locked loop alarm', to solve the problem.

3) Check whether there is any DSP alarm. If there is, refer to section VI, 'DSP


4) Check whether there is any power supply alarm. If there is, refer to section XI,

'Power supply alarm', to solve the problem.

5) Check whether TRX is firmly inserted.6) Replace TRX if the fault still can not be removed.

8.6 PBU


Alarm box

View alarm console information

Observe the status of PBU indicator

View hardware configuration status of maintenance console panel


High voltage standing-wave ratio alarm

Overtemperature alarm

Underpower alarm

Board communication alarm

Flash memory alarm

EPLD load times alarm





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EPLD upgrade failure alarm

Master clock alarm

Slave clock alarm

Clock critical alarm



the next step.

I. PBU high voltage standing wave ratio alarm

1) Check the connecting cable and connection input from PBU to CDU.

2) Reset PBU.

3) If the alarm continues, replace this PBU.

II. PBU over temperature alarm

1) Check the equipment temperature and environment control equipment.

2) Check the operation of rack fans.

3) If all the temperature control equipment works properly, replace this PBU

module.

III. PBU underpower alarm

1) Restart the equipment to see if it can be restored.2) If it cannot be restored, replace the said PBU module.

IV. PBU board communication alarm

1) Check if PBU is powered on.

2) Replace PBU.

V. PBU Flash memory alarm

1) Replace Flash memory.

2) Replace PBU.

VI. EPLD load times alarm

If EPLD is erased for times more than the threshold value (100 times), this alarm will

be generated.

VII. PBU EPLD upgrade failure alarm

If EPLD in Flash upgrade software fails to be loaded for three times consecutively,

this alarm will occur.





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VIII. PBU master clock alarm

1) Check TMU clock.

2) Check clock transmission line.

3) Check TDU.4) View if extended TMU is installed.

IX. PBU slave clock alarm

1) TMU clock.

2) Check the clock transmission line.

3) Check TDU.

4) View if extended TMU is installed.

X. PBU clock critical alarm

1) Check active and standby clock transmission line.

2) Check active and standby clock.

3) Replace PBU unit.

8.7 PMU


PMU indicator status

Hardware status display panel on the maintenance console


PMU, power frame backplane distribution line, power module PSU, sensor and its

circuitry, battery pack loop.


Board power-off

Power supply system alarm


I. Board power-off

In this case, the indicator RUN on PMU board is off, the board does not work, and

remote treatment becomes impossible.

1) First check whether PSU is switched on, and whether VOUT indicator is on. If

the indicator is off, then there must be no PSU voltage output.





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2) If VOUT indicator is on, measure whether the output voltage is normal.

If it does not fall within the operating voltage range, then PSU power supply is

abnormal

If it is normal, check whether PMU is properly inserted.

3) If the problem still exists, replace the PMU board

II. Power supply system alarm

In this case, the ALM system alarm indicator on PMU panel is on. It indicates that

there are faults in the power supply system. These faults can be viewed via the base

station maintenance console and they may be power module alarm, power

distribution alarm, and environment alarm.

III. Power module alarm

1) Power module fault

First check whether the input voltage and output voltage of the power frame fall within

the operating range.

If they do not, check the input power supply and output load

If they are normal, pull out the faulty power module from the backplane according

to the alarm power module address prompted in the base station maintenance

console. Then re-insert when all indicators are off. View the base station

maintenance console for any module fault alarm. If there is no fault alarm, then

the power module has recovered and can be put into use again. If the alarmreoccurs, replace the faulty power module.

2) Power module protection

The cause is that the power module input voltage exceeds the operating range or the

operating temperature is too high. Check whether there is any over/under-voltage in

the input power supply.

If it is abnormal, repair the input power supply

If it is normal, check whether the operating temperature of the power module is

too high or whether the cooling fan is faulty

If all the above are normal, pull out the power protection module from thebackplane according to the alarm power module address prompted in the base

station maintenance console. Reinsert the module when all indicators are off.

View the base station maintenance console for any module protection alarm. If

there is no alarm, then the power module has recovered and can be put into use

again. If the alarm reoccurs, replace the power protection module.

3) Power module communication failure

Check whether PMU and PSU are well inserted. If they are properly installed and of

good contact, check via the base station maintenance console to see whether the





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power module quantity and the data configuration of each module address are

correct.

If correct, check whether all the inserted modules fail in communication.

If all fail in communication and yet it is not sure whether the PMU is normal,replace the PMU. If PMU is confirmed to be normal, replace power frame

backplane.

If communication failure only occurs to some modules, interchange the positions

of the power modules of successful communication with those of communication

failure. If the modules that previously failed in communication still fail in

communication, replace the power module PSU. If the power module of

successful communication fails in communication after the interchange, replace

the power frame backplane.

IV. Power distribution alarm

1) AC input power-off or AC input over/under-voltage

In DC/DC power supply system, check whether module communication is successful.

If all fail in communication, refer to Subsection c (Power Module Communication

Failure) in Section 1) for solutions. When no power module is installed, check via the

base station maintenance console to see whether module quantity is set as 0. Check

the AC input distribution in AC/DC power supply system. If the distribution wires are

normal and AC input voltage is normal as well, check whether the PMU is well

inserted. If it is properly installed and of good contact, first consider replacing the

PMU. If AC input power-off alarm still exists, replace the power supply backplane.

2) DC output over/under-voltage

View the busbar voltage via the base station maintenance console and compare it

with the actual voltage.

If the over/under-voltage is caused by measurement error, check whether the

PMU is well inserted.

If it is properly installed and of good contact, consider replacing the PMU. If the

measurement is made correctly, check when there is DC over-voltage alarm

whether the power module or power supply input or power load is abnormal.

When there is DC under-voltage alarm, check whether the AC input, power

module or power supply input, and power load are abnormal.

3) Battery powered off

If the conditions for batteries being powered off are met, the monitoring module

should stop working and no battery powered off alarm should be detected due to

single power supply mode. Check whether the power-off contactor is working.

Replace it if it is not working.

4) Battery fuse broken





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Check whether the battery loop fuse, contactor and wiring are normal. If no problem is

found with the wiring of the battery loop and devices, check whether the PMU is well

inserted. If it is properly installed and of good contact, replace the PMU.

5) System output voltage abnormal There is wide differences between the busbar voltage and the specified output

voltage. If it is a DC/DC system, the problem may come from the power module

or the load. Check whether the power module and the load are abnormal.

If it is an AC/DC system, the problem may come from battery pack temperature

compensation, power module fault or the load. Check via the base station

maintenance console to see whether the measured value of the battery pack

temperature is correct. If the value is correct, do calculation using the following

formula:

Temperature compensation voltage = floating charge voltage – (battery packtemperature - 25) % temperature compensation coefficient

If the battery pack compensation voltage and busbar output voltage calculated

deviate within the error range (0.3V), then it is normal. If the deviation is too big,

check whether the power module and the load are abnormal.

If the temperature sensor measurement value is incorrect and there is no battery

pack temperature sensor attached, check whether the PMU is well inserted. If it

is properly installed and of good contact, replace the PMU. When there is a

battery pack temperature sensor attached, remove the temperature sensor.

And if the measured temperature value is the default value 25 ° C, then thetemperature sensor must be defective. Replace the battery pack temperature

sensor.

If the measured temperature value of the battery pack is not the default value,

the PMU temperature measurement circuit may be faulty. Replace the PMU.

V. Environment alarm

1) Ultra high/low ambient temperature or humidity

When installing temperature/humidity sensor, check via the base station maintenance

console to see whether the measured value is consistent with the actual value. If it is, tackle the environment problem.

If the alarm is caused by incorrect measurement, check whether the PMU is well

inserted. If it is properly installed and of good contact, replace the sensor first. If

the measurement remains inaccurate, replace the PMU. If no

temperature/humidity sensor is installed, check whether the PMU is well inserted.

If it is properly installed and of good contact, replace the PMU.

2) Smoke alarm, infrared alarm and soaking alarm

Check whether the PMU is well inserted. If it is properly installed and of good contact,

check whether there is any environmental alarm on the site mentioned above.





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If there is any such alarm, tackle the on-site environment problem.

If no such alarm, check whether there is any fault in the sensor and its line. If the

sensor and its line are normal, replace the PMU.

3) Door control alarmCheck whether PMU is well inserted.

If it is properly installed and of good contact, and no door control sensor is

installed, check whether there is short-circuit jumper connector in the door

control sensor interface MC on the power supply backplane. If there is not, install

short circuit jumper connector. If there is, replace the PMU.

If door control sensor has been installed, check the site for any environmental

alarm mentioned above. If such alarm exists, solve the on-site environment

problem. If there is no such alarm, check whether the sensor and its line are

faulty. If they are normal, replace the PMU.4) Fan alarm

Check whether PMU is well inserted.

If it is well installed and of good contact, check whether the rack feature No.

configured in the base station maintenance console is correct.

If it is, check whether the fan fault signal input connector has been installed in

the fan port of the power supply backplane. Install the connector if it is not

installed. If there is a line fault, solve the problem of fan fault signal input line.

If everything is normal, replace the PMU.

8.8 PSU


Alarm box

Alarm console

PSU indicator status



Power supply alarm

Proper power supply unavailable


The faults are cleared step by step. If one step does not work, go to the next step.

Under normal conditions, the two green indicators on the power module are on

simultaneously, and the red indicator is off.





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1) If the green input indicator (VIN) of the power module is on, while the green

output indicator (VO) is off or flashing, check by the following procedures.

Note:

When system output load is small, individual modules may not work (i.e., the VO

indicator is off) due to current equalization. Yet it should not be considered as a fault.

Check whether the faulty module is well installed, and whether the two fasteners

at the upper and lower sides of the panel are tightly screwed. If not, reinstall the

module following the specified module assembly procedure.

Check whether the system fan is running normally. If it is not running, turn on thefan.

When the fan is running normally, and the green output indicator (VO) remains

off, then it may be that the module has not yet received the PMU voltage

regulation signal. Please wait for half a minute and observe.

If the green output indicator (VO) remains off after the above steps, this module

must be faulty.

2) If none of the three indicators on the module are on, check by the following

procedures

Check the status of other power module indicators in the same system. If all of

them are off, check whether the power supply system input busbar (or connector

post) is live or whether the connection is loose. If any problem is found,

reconnect the input line.

If one or module indicators are on or it is sure the power system input busbar is

live, check whether the module is properly installed and whether the two

fasteners at the upper and lower sides of the panel are tightly screwed. If not,

reinstall the module following the specified module assembly procedure.

If the indicator remains off after the above steps, this module must be faulty.

If the green input indicator (VIN) and red indicator (ALM) on the module panel are off

while the green output indicator (VO) is on, it means that the module itself cannormally output power supply. Please make replacement if spares are available. If no

spares are available, this module can still work as before and normal power supply

function will not be affected.

3) If the red alarm indicator (ALM) on the module panel is on while the green output

indicator (VO) is off, check by the following procedures

Check the system monitoring for any input over/under-voltage alarms. If such

alarm is found, then it is normal that the red indicator (ALM) is on. When the

input voltage resumes normal, the module will also resume its normal operation.





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If the input voltage is normal, check whether the cooling fan of the system

cabinet has stopped running. When the fan has stopped for a long time, over

temperature protection will occur to the module. Pull out the alarm module

according to the power module replacement procedure. Detach the module fromthe power system and reinsert it into the power supply system frame a few

minutes later when it is cooled. Then the module should work normally,

otherwise it must be faulty and replacement is needed.

8.9 TEU


Alarm console

TEU indicator status

Hardware configuration status panel of the base station maintenance console


PSU, TES, TMU, Transmission line, E1 line.


Board power-off

Transmission line alarm

E1 link alarm

Calls can not be put through


I. Board power-off

In this case, all indicators on TEU board are off and the board does not work.

1) First check whether PSU is switched on, and whether VOUT indicator is on. IfVOUT indicator is not on, it means that there is no PSU voltage output.

2) Then check whether the TES power switch of the switch box on top of the

cabinet is on,

3) Check whether the PWR indicator of the TES board is on.

4) If they are all normal, check whether TEU is properly inserted.

5) If the problem still exists, replace the TEU board.

When the TEU is used for the optical transmission system, it is a public resource of

the whole network. If the transmission is interrupted due to improper operation,





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serious consequences will arise. Therefore, TEU power-off operation must be done

with extreme caution.

II. Transmission line alarm

In this case, the RUN indicator on TEU panel will indicate fault. For details, refer to

the instructions of various interface boards.

Seen from the OMC, transmission line alarm breaks up into transmission line

receiving alarm and transmission line sending alarm. Transmission line receiving

alarm means that all receiving lines of the board are blocked. Please check the

receiving lines.

Transmission line sending alarm means that all sending lines of the board are blocked.

Please check the sending lines.

III. E1 link Alarm

1) Off-board E1 alarm

This alarm means that faults have occurred to the E1 line. Check whether the E1 line

connectors are in good contact. E1 line transmits in 75 Ω and 120 Ω resistance

respectively. Check whether the setting of board toggle switch is correct. The default

value of the board is 75 Ω . Directly connect the receiving end and sending end of the

port using a 75 Ω coaxial cable to determine whether the board is faulty. If any alarm

occurs, it can be determined that the TEU board is faulty. Please replace the board.2) In-board E1 alarm

This alarm means that a fault occurs within the board. Please replace the board.

IV. Orderwire blocked

Check whether the board has 48V or 24V power supply input, i.e., whether the jumper

setting is correct (Jumpers of ASU and PAT are all set to 48V). Replace TEU board. If

the problem still exists, replace CMB backplane.

8.10 TES


Alarm console

TES indicator status






TMU, TEU, CDU


Board powered off

Board communication alarm


I. Board powered off

In this case, the PWR power indicator on TES board is off. The board does not workand remote treatment becomes impossible.

First check whether PSU is switched on and whether VOUT indicator is on. If the

indicator is not on, it means that there is no PSU voltage output. Then check whether

the TES power switch of the switch box on top of the cabinet is shut on. If they are all

normal, check whether the TES is properly inserted and whether the power cable of

the backplane is well connected. If the problem still exists, replace the TES board.

II. Board communication alarm

In this case, the ALM indicator on TES panel is on, indicating that a communication

fault has occurred to the serial port between TES and TEU, and the serial port

between the two boards is blocked.

First replace the TES board. If the communication alarm does not disappear, replace

the TEU board. If the alarm still exists, replace the CMB backplane.

Documents

02-Fault Analysis and Location