Major BTS Alarms_GSM

6.4Other Faults

6.4.1 Call Drops

All the BTS receive their clock synchronization signal from BSC. A peculiar problem might arise when this synchronization is lost. As described in section 8.2, while there are three priorities set in the BTS to receive its synchronization signal first two from the Rx clock & the last priority is its own internal clock.

When DN2 is inserted between BTS & BSC, DN2 receives the synchronizing signal from BSC & BTS receives this through DN2. Hence all the BTS are to be synchronized with the DN2 clock. E=In each DN2 card, port 7 & port 11 are for clock signals. Port 7 & port 11 are given the top priority & third priority is given to its own internal clock.

When all the sites in Surat zone were put on DN2 from the BSC, there was a problem in one DN2 cards port. Hence the third priority internal clock became the top priority & there was loss of synchronization between BSC & the BTS working on that port.

This site faced a severe problem of call drops i.e. none of the calls were able to be put through by that BTS. During such problem, alarms are reported only when a call drops in a particular time slot three consecutive times. Also the alarm is visible at the BSC end only.

The alarm reported at the BSC is Unsynchronized clear calls in a particular TRX. But initially the BSS team was not aware if the exact cause of the problem. The steps in solving it were:

The very first thing to be done is to connect to the BTS & open NOIKIA HUB MANAGER. Then check the DAC value in SYNCHRONIZATION. The correct DAC value is 2025. But the value there was 1093. This showed the loss of synchronization between BTS & BSC & hence the calls were not able to get through BTS to BSC in spite of perfect coverage. The DAC valus was changed & problem solved temporarily.

Then the same problem was reported several times. DAC value had to be changed each time

Then the DN2 port of this site was checked at the BSC. It was found out that this port had its synchronization through internal clock. Hence its priority 1 was brought back to BSC signal. This solved the problem

6.4.2 Link Failures

As soon as a microwave point-to-point link fails from any particular site, it stops receiving its signal. If E1s for many sites pass through this affected site, then all the successive sites will also stop receiving their signals. There are many reasons for link failure or fluctuations:

IDU RTM card/ODU Failure If an alarm is regarding Indoor or outdoor unit failures, then these units need to be replaced. However when the reason for fluctuations is not clear then first the IDU is replaced & system is kept under observation. If the problem persists then the RF cable from IDU to ODU is changed. Last priority is given to ODU change as this is mechanically a tough job.

BER (Bit error ratio) high- When bit error ratio is high, the losses in the cable increase more than the allowable limits. Hence the RF cables have to be replaced. If problems persist, then the ODU needs replacement.

Flexibus unavailable this is one of the most amusing problem faced. A rat at a site had damaged the Flexibus that carries the signal from RRI or FIU 19E.

6.4.3 TRX faulty

TRX faulty are the most common & frequent faults that occur. These are major fault. There are many reasons for it:

TRX faulty here a TRX is first given a soft reset by first blocking the TRX from NOKIA BTS MANAGER. If problem is not solved then a hard reset is given. The last option is to replace the TRX.

Antenna connection faulty It occurs when the links are not perfectly connected. When the Voltage Standing Wave Ratio (VSWR) reading is greater than 1.2 on TRX output port, then this alarm is reported. But it is reported only when TRX is idle.

TRX output power is high compared to threshold value. In this case, a hard reset is given to the TRX.

All the odd or even time slots do not take calls. The alarm is TCH blocked. Here the TRX has to be replaced.

6.4.4 BCCH missing

Whenever a site is down i.e. a site does not receive its E1 signal, all the sectors do not get the BCCH signal. Here the OMU signal between BSC & BTS is blocked. There are various reasons for this & the solution is to solve the corresponding alarms. This problem of BCCH missing is more likely to be reported in sites where there is only one TRX. So even if that single TRX having BCCH becomes faulty, this problem occurs 7 no calls can be made from that sector.

4.7NOKIA ULTRASITE EDGE BASE STATION

ALARM DESCRIPTION

The alarms are used for internal fault recovery & fault reporting to the BSC, NMS & to the BTS software Nokia BTS manager. They indicate the faulty units along with the reasons & possible rectifications for each of them. This alarm system makes the life of a BSS engineer pretty easy.

4.7.1 Identifying faulty units

Nokia BTS manager helps in identifying faulty units. It shows an Alarm window with an object column giving the object that the alarms refer to, the accompanying unit, rack, shelf & slot. The severity column indicates the level of alarm. The equipment view shows the location of the units in the cabinet.

Unit location numbers are used for locating units which are numbered in the order from top to bottom & left to right by

RACK

specifies the rack of the cabinet

SHELFspecifies the shelf of the rack

SLOT

specifies the location on the shelf

The following is an alarm window which is seen when we open the NOKIA BTS MANAGER software..

Nokia BTS manager X

File Commissioning BTS SW Objects Supervision Tests tools Windows Help

TIME DESCRIPTION

12.00 received message

12.10 hardware configuration on

12.12 test calls on

ALARMS

Severity code time event description object state

Critical 8050 12.12 cancel loss of incoming signal tre enabled

Minor 7801 12.10 start MMI connected BCF() enabled

Faults are classified as minor (*), major (**) & critical (***). However there can be only one critical (***) alarm from a particular unit.

In reclassification the alarm handling detects which logical base station object is affected by a unit level fault. After reclassification, an object level alarm is issued according to a certain hierarchy. The steps are as follows.

1. ALARM OUTPUT

7606 TRX faulty ( TRX1 )

TRX 1 becomes faulty & ceases to operate so 7606alarm is issued.

2. Alarm output in this order



7603 BTS faulty ( BTS1 )



Now both TRXs are not operating, which causes BTS1 cease to operate so 7603 alarm is issued

3Alarm output in this order



7603 BTS faulty ( BTS1 )



7603 BCF faulty ( BCF )



Now both TRXs are not operating, which causes BTS1 cease to operate so 7603 alarm is issued



Now both TRXs of BTS2 are not operating, which causes BTS2 cease to operate so 7600 alarm is issued

4Alarm output in this order


7607 TRX degraded ( TRX2 )

7603 BTS operation degraded ( BTS1 )

TRX 1 becomes faulty & ceases to operate so 7606 is issued.

TRX 2 becomes partially faulty but calls are getting through so 7607 TRX DEGRADED alarm is issued.

Now the sector is partially faulty, & a BTS alarm 7604 OPERATION DEGRADED is issued.

4.7.2 Alarm Table

An alarm table consists of the following fields:

1234 ALARM NAME

Severity:Object affected:Object state:Unit:

Shows the alarm severity as displayed at the BSC or NMS as:

* minor

**major

***critical

User defined

The logical object affected by the fault.

The options are:

BCF, BTS, TRX, TRE, RTSThe state of the affected object at the time the alarm is issued. The options are

Enabled

DisabledThe alarm origin. Option are BOI, RTxx TSxx etc.

Fault reason:InstructionsAlarm Canceling:

This field describes the cause of the alarm e.g.

BOI temperature is dangerously high.This gives the instruction for the operator how to correct the fault e.g.

1. Ensure that station temp is within limits

2. check fans

3. If ok, change BOI.It describes how the alarm is cancelled. Options

Automatic

Manual

The following is the list of alarms that I have come across till now & have done the necessary rectifications at various sites across Surat. This Alarms are received at the O&M dept. in A`bad who in turn informs the BSS dept with the details. The next step is to go to the particular site & log into the BTS through the Nokia BTS manager (plug in BOI card).

1. 7208 - LOCAL BLOCK

Meaning: When units are supposed to be changed which are already plugged in, they should first be blocked. This is done by selecting the block options from the BTS manager. Local block signal is sent to the BSC. The following operations take place when a blocking signal is given:

BTS sends a cancel message to blocked unit alarms which have been reported to the BSC before block.

BTS sends the alarms of this unit to BSC

BTS no longer send alarm of the blocked unit to the BSC

Severity: *

Object affected: BCF, BTS or TRX

Object state: Disabled

Instructions: No actions required.

Alarm canceling: Automatic.

2. 7401 to 7424 EXTERNAL ALARM

these are user defined alarms which are given at the site e.g. fire, smoke detector etc.

3. 7602 BCF NOTIFICATION

Meaning: This mainly notifies the O&M about the physical status the BTS site.

Severity: *

Object affected: BCF

Object state: Enabled

Reasons: BOI, VXxx temp low/high, loose connections etc.

Instructions: check the fans/heaters, connections or units

Alarm canceling: Automatic

4. 7603 BTS FAULTY

Critical fault in the unit of a particular sector. It blocks the alarming sector.

Severity: ***

Object affected: BTS


Instructions: check for 7606 TRX faulty alarm or any other specific component alarm.


5. 7604 BTS OPERATION DEGRADED

This is the most common & recursive major fault. degradation indicates that the calls are still being put through but still there is some major problem with the units.

Severity: **

Object affected: BTS


Reasons: RX levels differ too much between main & diversity antenna.

Instructions: check the RSSI measurements by BTS manager. The most frequent problem is loose connections. Locate the cause of the alarm (unit cable antenna etc.). The units have to be manually checked.


6. 7606 TRX FAULTY

This is also a common major alarm. Till date I have attended 7 such alarms & replaced 5 TRX at those sites.

Severity: **

Object affected: TRX


Reasons: In particular are

Antenna connection faulty check the cabling. If Ok then TSxx unit is faulty which has to be replaced.

Fault in VSWR antenna monitoring a hard reset if software reset doesnt work.

Failure detected during TRX configuring TSxx unit is either faulty or its frequency band is different from the one that was configured into BSC.

BOI detected that connection to TRX is lost TRX communicate to BOI through BB2F. Hence the culprit is BB2F card.

A fault is reported if a particular TRX is locked remotely from O&M. So this is supposed to be considered first before any trouble shooting.

If the first TRX of the sector with BCCH is affected, then BCCH has to be reconfigured from BSC.

The very first thing done with these faults is a software reset & then a hardware reset (it is given by just plugging out & re plugging the TRX. )Alarm canceling: Automatic.

7. 7607 TRX OPERATION DEGRADED

Meaning: Though a TRX is able to put through calls, but there arises few problems which just degrades its operation which may also result in call droppings.

Severity: **

Object affected: TRX


Reasons: Flash operations (memory operations) fail in BOI or TRX. The other reasons are ill functioning of DVDx, power supply or IF synthesizers.

Instructions: Replace the BB2F card for failed flash operations.

Alarm canceling: Automatic

8. 7801 MMI CONNECTED TO BASE STATION

Meaning: MMI or Man Machine Interface means PC is connected to the front panel connector of BCF. Normal functioning of BTS is not at all affected. This software supports several local operations. BCF or Base Control Functions unit is responsible for operation & maintenance of the BTS. Its main functions are

Loading of BTS operational file packets from BSC to BTS

Initializing of BTS

Continuous supervision of BTS equipments.

It is the source of main clock pulse.

Frequency hopping operations but Airtel does not implement frequency hopping.

This alarm is always present as soon as the Nokia BTS manager is connected to BTS & goes away when disconnected.

Severity: *



7738 BTS WITH NO TRANSACTIONS

Meaning

The BTS has had no successfully terminated calls, SDCCH transactions or

GPRS TBF releases during the supervision period.

The alarm is used for supervising the BTS traffic capacity and to

indicate a sudden loss of service on BTS level.

Supplementary information fields

1 reason for the alarm (hex)

1 = no successful SDCCH seizures

2 = no successful TCH seizures

3 = no successful SDCCH nor TCH seizures

10 = no successful GPRS transactions

11 = no successful SDCCH seizures and no succesful GPRS transactions

12 = no successful TCH seizures and no succesful GPRS transactions

13 = no successful SDCCH nor TCH seizures nor GPRS transactions

Instructions

Find out the reason for the loss of BTS traffic capacity and bring

the BTS back to use. This may reqire for example locking, resetting and

unlocking the BTS or BCF object. Note that these actions cause both CS

and PS traffic to drop within the entity that has been reset. To

restore the GPRS service in a BTS, disabling and enabling GPRS (GENA=N,

GENA=Y) in the alarmed BTS may be sufficient.

Check that the parameters in connection with the alarm are reasonable.

Too short a supervision period may cause false alarms.

The MML command EEO outputs the radio network supervision parameter

values, and the EEN command modifies the parameter values.

Parameters, with their default values, affecting the alarm:

ZEEN: SMBNT= supervision start time (08-00)

EMBNT= supervision end time (18-00)

PRDBNT= length of supervision period (120 min)

Cancelling

The system cancels the alarm once it detects the BTS traffic capacity

has been restored, that is, when a normal channel release of the

type that was faulty occurs or, in case of a GPRS related cause, when

a successful TBF release occurs in the BTS. Note that if the alarm was

originally raised with both CS and PS reasons (16..19), and the

service occures either to PS or to CS domain, the alarm may remain for

the other domain.

The user can also cancel the alarm with the EOR command after

correcting the fault as presented in the INSTRUCTIONS.

All supplementary alarm fields are set to zero irrespective of wheter

the alarm is cancelled manually or by the system.

7734 BCCH IS NOT AT PREFERRED BCCH TRX

Meaning

The BTS has at least one TRX defined as the preferred BCCH TRX but

the BCCH channel is not on such a TRX so the BCCH coverage may

have decreased.

This alarm is not set if the BCCH MISSING alarm is active.


Instructions

This alarm usually results from a fault affecting the BTS's preferred

BCCH TRX. Check the radio network configuration with the MML command

EEI or the transceiver parameters with the MML command ERO.

Check active alarms with the MML command EOL and find out the

reason for the preferred BCCH TRX fault based on other alarms affecting

the BTS in question. Act according to the instructions of the other

active alarms. Check that the system moves the BCCH to the preferred

BCCH TRX and cancels this alarm.

Cancelling

Do not cancel the alarm. The system cancels the alarm automatically

when the fault has been corrected and the BCCH has been moved back

to the preferred BCCH TRX.

7730 CONFIGURATION OF BCF FAILED

Meaning

Configuring the radio network object from the BSC failed. The object is

not transmitting traffic.


1 general error message of the system. You can check its meaning

with a command of the service terminal extension MRS or in the

General Error Messages of System

255 UNSUCCESSFUL_EC

other malfunction between the BSC and the BTS

10675 OML_FAILURE_EC

configuring the BCF failed because of the O&M link state

11152 NBR_OF_FUS_NOT_CONSISTENT_EC

number of frame units is not consistent with the BTS

database

11153 BTS_DATABASE_DOES_NOT_EXIST_EC

BTS database does not exist

11154 NBR_OF_CUS_NOT_CONSISTENT_EC

number of carrier units is not consistent with the BTS

database

11155 DB_CREATED_BY_OLD_MMI_VERS_EC

database was created with an old MMI version

11156 INVALID_OBJ_TYPE_IN_MSG_EC

message contains an invalid object type

11157 RESP_FROM_BTS_TIMEOUT_EC

BTS has not responded within time supervision

11160 CONF_COMPL_TIMEOUT_EC

configuration was not completed within time supervision

11165 GUP_ACK_TIMEOUT_EC

radio network configuration management system is temporarily

out of resources

11365 ILLEGAL_DB_FORMAT_EC

BTS does not support the database format

11371 INV_CELL_CONFIG_EC

cell configuration is not compatible with the current

hardware

11372 INV_HOPPING_MODE_EC

hopping mode is invalid due to the restrictions of the

hardware

11373 NO_FTRX_EC

BTS has no floating TRXs

11478 NBR_OF_TRX_EC

number of TRXs in the configuration message is not consistent

with the BTS

12892 STATE_CHANGED_NOT_RECEIVED_EC

BSC has not received the BTS_STATE_CHANGED message because

TRX configuration failed

13443 REALTIME_UPD_OML_FAIL_EC

updating the current time failed because of a O&M link fault

14951 REALTIME_UPD_OML_BUSY_EC

updating the current time failed because of O&M link busy

14969 TRX_NOT_EDGE_CAPABLE_EC

all TRXs under under BTS must be EDGE capable when EGPRS is

enabled in BTS

Instructions

Correct the fault indicated in the supplementary information field.

If the error code in the supplementary information field is

11165 or 255, lock and then unlock the BCF with the MML command EFS.

If the error code is 10675 and background parameters are being activated,

you must make the necessary radio network parameter modifications

manually for the BCF in question after the activation. After that,

lock and unlock the BCF with the MML command EFS.

If the error code is 13443 or 14951, the current time and date in the BSC

can be updated for the BTS by locking and unlocking the BCF.

If the error code is 14969, make the TRX EDGE capable or

disable EDGE capability of BTS. After that, lock and unlock the TRX with

the MML command ERS.

Cancelling


when the fault has been corrected.

7737 INCONSISTENT DATA IN RADIO RESOURCE MANAGEMENT STATE FILES

Meaning

BSC's radio resource management state files are faulty and as a result,

the BTS's traffic capacity may have decreased. The system

has attempted to return the state files back to normal by means of

an automatic procedure.


1 estimate on BTS's traffic capacity after the restoration

0 test alarm, normal traffic capacity

1 traffic capacity has been returned to normal

2 traffic capacity has decreased

3 traffic capacity has substantially decreased

2 number of SDCCH channels working

3 number of full rate TCHs working

4 number of half rate TCHs working

5 number of blocked radio time slots

6 number of radio time slots removed from service

7 detector

C channel search algorithm

8 execution phase at which the fault was detected

9 total count of errors detected in state files

Instructions

Use the service terminal log extension LOGUTI command ZGSC

to output the log file of both the WO-MCMU and the SP-MCMU and save

the data.

You can monitor the BTS traffic capacity by using the BSC's

statistics measurements, radio network supervision function and

the E00HAN service terminal extension (Radio Resource Data Monitoring).

If the cell's traffic capacity has decreased due to a fault, delete

the BTS and create it again in the BSC.

Cancelling

Cancel the alarm with the EOR command after correcting the fault

as presented in the INSTRUCTIONS.

7729 RADIO NETWORK RECOVERY FAILED

Meaning

The BSC radio network fault recovery failed. The cause of the failure

is one of the following:

- reading the radio network configuration data failed

- the BCF-specific recovery buffer in the alarm system is full

- re-sending a fault has been attempted the maximum number of times

- the recovery system sent a DX error code in its acknowledgement

- recovery was interrupted because of a system restart.

The result may be a cell which does not transmit traffic because

radio network recovery has not received the fault, or a cell whose

capacity is out of use although it is not faulty, or a recovery

action which could not be terminated.


1 PCM identifier

2 DCS identifier as a hexadecimal

3 number of the recovery action being processed

4 identifier of the alarm system's filtering buffer

5 general error message of the system. See General Error Messages of

System for error code explanations.

Instructions

1. Check the supplementary information field 4 (buffer id). If the

value is FF, go to step 5. If the value is not FF, perform steps 2-4.

2. Use the MML command EOL to check active alarms. Use the MML command

EOH to check the state of the alarm object (BCF) in the alarm history.

Check the state in the latest alarm directed to the BCF in question,

excluding this alarm.

3. Use the MML command EEI to check object states in the radio network

database.

The object state is wrong in the database, if

- alarm object state is DISABLED but WO in the database or if

- the object has no active alarms but its state is BL in the database.

4. Use the MML command EFS to lock the object which is in the wrong state

in the database and then unlock it with the same command. This updates

the correct object state in the radio network database.

5. Examine the alarm printout to find out the alarm object. If the object

is a radio network database object, perform step 6. If the object is

partly unknown (bcf id known), perform steps 7-8.

6. Lock and then unlock the alarm object. Use the MML command EFS for a

BCF, EQS for a BTS and ERS for a TRX.

7. Use the MML command EEI to check if the object has been created. If it

has not, create it. See instructions on BSS Integration

8. If the TRX id is 255 and the BTS type is Nokia Talk-family or Nokia

PrimeSite, check the logical IDs according to instructions in

BTS documentation.

Cancelling

Cancel the alarm with the MML command EOR after correcting the fault

as presented in the INSTRUCTIONS.

7725 TRAFFIC CHANNEL ACTIVATION FAILURE

Meaning

The system has blocked the radio time slot because the call

control has failed a number of times in the activation of

a traffic channel.


1 Type of the channel whose TCH activation failed

The channel type can be "TCH" , "SDCCH" or "Packet Data TCH".

The number value "0" indicates "TCH", "1" indicates "SDCCH"

and "2" indicates "PDTCH" (Packet Data Traffic TCH).

Instructions

if the failure type is "PDTCH", the alarm is cancelled automatically

by the system, when no more failure indications are observed

if the channel type is "TCH" or "SDCCH", cancel the alarm with the MML

command EOR. Deblock the radio time slot by first aligning the TRX

in question with the command ERS and then removing the alignment

of the TRX

Cancelling

If the channel type is "TCH" or "SDCCH", cancel the alarm with a command

before taking the steps described in the INSTRUCTIONS, if the alarm has

not been cancelled before. See instructions on base transceiver station

alarms handling.

7723 FAILURE IN SENDING SYSTEM INFORMATION TO BTS SITE

Meaning

A failure has occurred in sending the system information

to the BTS site after the recovery measures or configuration changes

of the BSS radio network. The TRX in question or the whole cell

may be unable to transmit traffic.


1 task in which the error occurred

03 failure in the TRX

04 cancelling of the TRX failure

06 cancelling of a cell-specific failure

09 restart of the BCSU

0A restart of the BTS site

0B a correction request of the TRX configuration from the call

control

0C BTS/TRX Unlock command given by means of an MML command

0D configuration change done by means of an MML command

0E battery backup recovery of the BTS site

12 sending of periodic system information

13 updating of access classes

14 restart of the TRX

15 blocking due to background parameter update

16 deblocking due to background parameter update

17 updating background parameter changes

2 general error message of the system. You can check its meaning

with a command of the service terminal extension MRS or in the

General Error Messages of System

Instructions

If the value of the supplementary information field 1 (Interrupted task)

is 12 or 13, cancel the alarm (MML command EOR).

If the value is other than 12 or 13, set the TRX into LOCKED state

and then to UNLOCKED state with the MML command ERS.

If the alarm is still active, check other alarms and error codes.

If one of them indicates a LAPD link failure, BCSU reset, BTS failure

or a disturbance in the radio network database, act according to the

instructions of the alarm in question.

If the alarm is still active, set the TRX into LOCKED state and then to

UNLOCKED state with the MML command ERS.

If none of the previous measures were effective, set the BCF in question

first into LOCKED state and then into UNLOCKED state with the

MML command EFS.

NOTE! All calls in that BCF will then be released.

Cancelling



7720 SDCCH ACTIVATION FAILURE

Meaning

Activating the control channel has failed a number of times.


1 subtime slot identifier of the radio time slot

Instructions

The disturbance may be temporary, in which case no actions

are needed.

If the disturbance recurs repeatedly in the same base station,

find out the reason for the disturbance.

Cancelling

No cancelling.

7717 WORKING HALF RATE TCH RATIO BELOW THRESHOLD

Meaning

The radio network configuration and failure management

has detected that the ratio between the number of half rate

traffic channels in the cell in normal working state

(UNLOCKED-WORKING) and the number of unlocked half rate

traffic channels in the cell is below the defined threshold.

Only one alarm per cell is possible. Object of the alarm is the

BTS which has the BCCH timeslot.


1 N = normal TRX

E = extended range TRX

Instructions

Check why half rate traffic channels in the cell in normal working state

(UNLOCKED-WORKING) or unlocked half rate traffic channels in the cell

are out of use.

If the reason is a faulty TRX, correct the fault.

This increases the number of channels in normal working state,

and the alarm is removed automatically.

The BSC-specific threshold value of the alarm can be changed

with the MMI command EEQ.

The new threshold value takes effect as soon as the ratio of

the channels changes, for example, when the administrative

state of the TRX is changed, or the TRX's operative state

changes.

The following formula is used in calculating the ratio:

( number of WO and BL-SHD half rate and dual rate traffic

channels in the cell/ number of all half rate and dual rate traffic

channels in the cell excluding those in BL-USR state ) * 100

Cancelling



7712 WORKING SDCCH CHANNEL RATIO BELOW THRESHOLD

Meaning

The radio network configuration and failure management

has detected that the ratio between the number of SDCCH

channels in the cell in normal working state (UNLOCKED-WORKING)

and the number of traffic channels in the cell in normal working state

(UNLOCKED-WORKING) is below the defined threshold.

Only one alarm per cell is possible. Object of the alarm is the BTS

which has the BCCH timeslot.


1 N = normal TRX


Instructions

Check why SDCCH channels in the cell in normal working state

(UNLOCKED-WORKING) or traffic channels (full and half rate)

in the cell in normal working state

(UNLOCKED-WORKING) are out of use. If the reason is a

faulty TRX, correct the fault. This increases the number of

SDCCH channels in normal working state, and the alarm is

removed automatically.



The new threshold value takes effect as soon as the ratio of

the channels changes, for example, when the administrative

state of the TRX is changed, or when the TRX's operative

state changes.


( number of WO and BL-SHD SDCCH channels / number

of WO and BL-SHD traffic channels ) * 100

Cancelling



7711 WORKING FULL RATE TCH RATIO BELOW THRESHOLD

Meaning

The radio network configuration and failure management has

detected that the ratio between the number of full rate traffic

channels in the cell in normal working state (UNLOCKED-WORKING) and

the number of unlocked full rate traffic channels in the cell is

below the defined threshold.

Only one alarm per cell is possible. Object of the alarm is the BTS

which has the BCCH timeslot.


1 N = normal TRX


Instructions

Check why full rate channels in the cell in normal working state

(UNLOCKED-WORKING) or unlocked full rate channels in the cell are

out of use.

If the reason is a faulty TRX, correct the fault.

This will increase the number of channels

in normal working state, and the alarm is removed automatically.



The new threshold value takes effect when the ratio

of the channels changes, for example, when

the administrative state of the TRX is changed, or when

the TRX's operative state changes.


( number of WO and BL-SHD full rate and dual rate traffic

channels / number of all full rate and dual rate traffic

channels excluding those in BL-USR state ) * 100

Cancelling



7617 SEVERAL CALLS DROPPED DUE TO PROBLEM WITH TRANSCODER

Meaning

There is an error with the connection between the base station and

the transcoder.


1-6 XX XX XX XX XX XX

1 2 3 4 5 6

1) rack (cabinet) number 4) type of unit

2) shelf number 5) unit number

3) slot 6) subunit number

For more information, see Alarm Structure

Instructions

METROSITE and CONNECTSITE 10:

Fault reason : There is an error with the connection between the BTS

and the transcoder.

Instructions:

1. Check the transmission path between the base station

and the transcoder.

ULTRASITE and CONNECTSITE 100:

Fault reason : There is an error with the connection between the BTS

and the transcoder.

Instructions:

1. Check the transmission path between the base station

and the transcoder.

Cancelling

This is a start/cancel type alarm. Alarm is cancelled automatically

or manually.

7607 TRX OPERATION DEGRADED

Meaning

Critical fault has occurred in a TRX.

The fault reason can be read from the supplementary text field

of the alarm.



1 2 3 4 5 6





Instructions


All fault reasons

Instructions:

See the Alarm Descriptions document included in the BTS SW

release binder of the alarming base station type.


Fault reason : The reflected power of remote tune combiner is too high.

Instructions:

1. Check the antenna connection to the remote tune combiner.

2. If the antenna connection is OK, replace the remote tune combiner.

Diversity branch is still working and calls are getting through.

Fault reason : Fault in the chain between power unit and MHA.

Instructions:

1. Check the chain between the power unit and the MHA.

2. If the chain is OK, replace the MHA.

Fault reason : Fault in VSWR antenna monitoring.

Instructions:

1. Check the antenna and cabling. If either the antenna or cabling are

faulty, replace the faulty units and reset sector to cancel

the alarm.

2. If the antenna and cabling are OK, the TSxx is faulty. Replace the

faulty TSxx.

Diversity RX branch is still working and calls are getting through.

Fault reason : No connection to dual variable gain duplex unit.

Instructions:

1. Check the BTS configuration and install the DVxx if it is missing.

Fault reason : TRX is unable to implement EDGE services.

Instructions:

1. Check the configuration of TRXs.

2. Upgrade the TSxx/BB2x units to EDGE capability.

Fault reason : IDD main/auxiliary TRX frequency band mismatch.

Instructions:

Note: IDD auxiliary TRX.

1. Check the IDD configuration of the BCF.

2. Check the configuration of the TRX.

3. Replace the IDD auxiliary TSxx with one of the same frequency as

the IDD main TSxx unit. The TSxx units used for an IDD pair must

be of the same type.

Fault reason : Mismatch between BSC/MMI configuration and/or IDD TRX.

Instructions:


1. Delete the IDD auxiliary TRX from the BSC configuration.

2. Reset the IDD main TRX.

IDD auxiliary TRXs are not to be defined at the BSC.

Fault reason : Non EDGE TRX device type used accidentally in IDD mode.

Instructions:


1. Check the IDD configuration of the BCF.

2. Check the configuration of the TRX.

3. Replace the IDD auxiliary TSxx with an EDGE capable unit.

IDD TRXs must be EDGE capable.

Other fault reasons

Instructions:

See the Alarm Descriptions document included in the BTS SW

release binder of the alarming base station type.

Cancelling



7605 BTS NOTIFICATION

Meaning

A minor fault (or faults) has occurred in a unit (or units) that

belong to the sector indicated in the alarm.

Check the fault reason from the supplementary text field of the alarm.



1 2 3 4 5 6





Instructions


Fault reason: Fan unit operation degraded

Instructions:

1. If something has jammed the fan unit, remove the jamming object.

Otherwise replace the fan unit.


Fault reason: Remote tune combiner flash checksum is invalid

and the code is corrupted.

Instructions:

1. Reset BCF.

2. If the fault reappears, replace the remote tune combiner.

Fault reason: Cavity stepper motor cannot tune the remote tune combiner.

Instructions:

1. Reset BCF.

2. If the fault reappears, replace the remote tune combiner.

Fault reason: Remote tune combiner has lost connection to

temperature sensor.

Instructions:

1. Replace the remote tune combiner.

Cancelling



7608 TRX NOTIFICATION

Meaning

Minor fault has occurred in a TRX.

The fault reason can be read from the supplementary text field of the alarm.



1 2 3 4 5 6




See alarm instructions.

Instructions

METROSITE:

7608 alarm not used in METROSITE.

ULTRASITE:

Fault reason : TSxx internal I 2 C bus is jammed.

Instructions:

1. Reset the TRX.

2. If the fault reappears, replace the TSxx.

Fault reason : Impossible to execute TRX loop.

Instructions:

1. Reset the TRX.

2. If the fault reappears, replace the TSxx.

Fault reason : BB2 temperature is low.

Instructions:

1. Replace the BB2.

Fault reason : TSxx temperature is low.

Instructions:

1. Replace the TSxx.

Fault reason : BB2 has lost connection to temperature sensor.

Instructions:

1. Temperature sensor is probably broken.

Temperature changes cannot be measured. Replace the BB2.

Fault reason : TSxx has lost connection to temperature sensor.

Instructions:

1. Temperature sensor is probably broken.

Temperature changes cannot be measured. Replace the TSxx.

Cancelling

This is a start/cancel type alarm. Alarm is cancelled automatically.

7602 BCF NOTIFICATION

Meaning

A minor fault (or faults) has occurred in the base station.

The fault reason can be read from the supplementary text field of the

alarm.



1 2 3 4 5 6




See Alarm Structure

Instructions


Fault reason: Temperature inside the TRX is high.

Instructions:

1. Check whether the following alarm is active for fan unit:

7605 BTS NOTIFICATION

and follow the instructions given for the alarm.

2. Even if there are no active alarms for the fan unit, check that no

foreign objects obstruct the airflow.

3. If alarm 7605 is not active, ensure that the ambient temperature of

the base station is within acceptable limits.

Fault reason: Temperature inside the TRX is low.

Instructions:

1. Ensure that the ambient temperature is within acceptable limits.

also check the fan unit.

Fault reason: Fan unit is broken.

Instructions:

1. Check whether the fan unit is installed.

2. When there is a fan unit installed, check if something has jammed

the fan unit and remove the jamming object. Otherwise replace the

fan unit.

Fault reason: External synchronisation signals disabled

Instructions:

1. Check the synchronisation cabling.

2. Check the synchronisation source (Master BCF or Location Measurement

Unit (LMU)).

3. If 1. & 2. above are OK, replace the BCF.

4. Restart BCF

Fault reason: Base Station synchronisation failed

Instructions:


2. "--> To be verified by BTS-side."

3. Restart BCF


Fault reason: Power unit output voltage fault.

Instructions:

1. Replace the faulty power unit.

Other power units are still functioning.

Fault reason: Power unit input voltage fault.

Instructions:

1. Replace the faulty power unit.

Other power units are still functioning.

Fault reason: No connection to power unit.

Instructions:

1. Check if the power unit is switched off.

2. If the power unit is on, replace the faulty power unit.

Fault reason: Mismatch between BSC/MMI configuration file

and the actual configuration.

Instructions:

1. Check the base station configuration and the configuration file.

Make necessary corrections.

Fault reason: CCUA PSM alarm 1

Instructions:

1. Use the Node Manager software to check the active SISU alarms and

follow the instructions given in the SISU operating manual.


Instructions:




Instructions:



Fault reason: Heater is broken.

Instructions:

1. Replace the faulty heater, or the heater is not installed although

it is defined in the configuration file, therefore an alarm is

issued.

Install the heater.

Fault reason: External synchronisation signals disabled

Instructions:


2. Check the synchronisation source (Master BCF or Location Measurement

Unit (LMU)).

3. If 1. & 2. above are OK, replace the BCF.

4. Restart BCF

Fault reason: Base Station synchronisation failed

Instructions:


2. "--> To be verified by BTS-side."

3. Restart BCF

Other fault reasons

Instructions:

See the Alarm Descriptions document included in the BTS SW release

binder of the alarming base station type.

Cancelling

This is a start/cancel type alarm. Alarm is cancelled automatically.

7601 BCF OPERATION DEGRADED

Meaning

A major fault (or faults) has occurred in the base station.

Check the fault reason from the supplementary text field of the alarm.



1 2 3 4 5 6





Instructions


Fault reason: Cabinet I2C bus is jammed.

Instructions:

1. Switch the site power Off and On.

2. Check the fan unit, the power supply unit and the TRXs.

If necessary, replace the faulty units(s).

3. If the fault reappears, replace the cabinet. The units

inside the cabinet can be reused in the new cabinet.

Fault reason: Incompatible unit presence has been detected in the BTS.

Instructions:

1. Replace the high power or EDGE TRX(s) with normal type TRX(s)

and reset the BCF.

2. Or, replace the normal type FAN and power supply with high power

or EDGE units. Now EDGE and high power TRXs are supported.

Other fault reasons

Instructions:

1. Check whether one or several of the following alarms are active:

7606 TRX FAULTY

7603 BTS FAULTY

7607 TRX OPERATION DEGRADED

7740 BEATING BTS ALARM

Meaning

The same radio network alarm has changed its alarm state (start/cancel)

20 times consecutively, always during informing or cancelling delay,

and has thus been filtered by the alarm system. The same radio network

object is the object of both this alarm and the beating alarm that

caused this alarm.


1 the alarm number of the beating BTS alarm

2-15 if the beating alarm has any additional information, it is

indicated here. Additional information is cut after 14

bytes and it is represented in hexadecimal format.

Instructions

Correct the fault that caused the original beating alarm. You can

find the number of that alarm in Supplementary information field 1.

Cancelling

Cancel the alarm with an MML command after correcting the fault as

presented in INSTRUCTIONS. See Alarm Administration.

7741 MEAN HOLDING TIME ABOVE DEFINED THRESHOLD

Meaning

The mean holding time on the channel specified exceeds the

operator-defined threshold during the measurement period.

The alarm is used to supervise the functioning of the traffic and

signalling channels. It reveals unreleased calls.


1 subchannel identification

00 - 01: TCH/H subchannel

F0 : TCH/F subchannel

C0 - C7: SDCCH subchannel

2 mean holding time on the channel during the measurement period

in minutes

3 number of seizures on the channel during the measurement period

4 shortest seizure on the channel during the measurement period

in seconds

Instructions

Find out whether the channel seizure that caused the alarm is a real

call or an unreleased channel.

Use the service terminal command S:,,

B,

Major BTS Alarms_GSM

Documents

bts bsc

bsc bts

bsc signal

dn2 port

dn2 clock

clock synchronization

priority internal clock

bsc end