Major Alarms

Some of the Important Alarma:-

Alarm Number Description

7745 CHANNEL FAILURE RATE ALARM

2992 bts and tc unsynchronization clear calls on a interface

2993 bts and tc unsynchronization clear calls on abis interface

7508 RADIO TIMESLOT FAILURE IN TRX

7600 BCF FAULTY

7601 BCF OPERATION DEGRADED

7603 BTS FAULTY

7604 BTS Operation Degraded

7606 TRX FAULTY

7617 SEVERAL CALLS DROPPED DUE TO PROBLEM WITH TRANSCODER

7704 PCM FAILURE

7705 LAPD FAILURE

7715 CONTINUOUS RESTARTS OF BCF-TRX

7725 TRAFFIC CHANNEL ACTIVATION FAILURE

7738 BTS WITH NO TRANSACTIONS

7743 MEAN HOLDING TIME BELOW DEFINED THRESHOLD

2955 TRANSCODER CHANNEL FAILURE

7746 CH CONGESTION IN CELL ABOVE DEFINED THRESHOLD

7767 BCCH MISSING

7939 FORWARD POWER TOO LOW AT TX ANTENNA

8112 FREQUENCY ERROR

ALARM NUMBER 7745:- CHANNEL FAILURE RATE ABOVE DEFINED THRESHOLD: This alarm helps in finding out the timeslots which are blocked and causing High SDCCH or TCH Blocking.And in some scenarios calls get established on these timeslots and then drops with an cause of “Time out”. Alarm 7745 is explained as described below with an example.

Alarm number 7745 gives information on the Timeslot degraded. This displays degradation of both SDCCH Timeslot and TCH Time slots that have gone faulty.At the foremost instent a soft reset (Locking that particular Time slot and then unlockimg )can help in overcommng the problem.If it is found to have all the Timeslots degraded ,then that particular TRX can be given a reset on a temporary basis. If the Problem still exists then change the TRX. Causes: 1) If Alarm noticed on BCCH Carrier, then swap BCCH /TCH Carrier appropriately. 2a) 7745 on One TRx Only: If there is alarm noticed on one single TRx, then check for SMA Cable(Cable that connects the Radio) at TX Connector to WCxA

(Wide band combiner) of the TRx is properly tightned. 2b) 7745 on Two TRx of a cell. If alarm noticed on two TRx’s, then check if there exist, cross feeder in these two TRx’s 2c) Noticed on all TRx. Check for Cross feeder, Bad connectors, Connection to DVxA (Duplexer). Solution:

a) Temporary => Inservicing appropriate Time slots. b) Permanent => Replace Hardware (Radio).

STATISTICS ANALYSIS:7745. The statistics showing no calls been handled by a particular Timeslot found to be having this alarm 7745.

Time slot number “2” showing Alarm 7745 for “TRX -002” of Site “AMITYSCHL1” of “BSC015”

Statistics showing no calls been handled by this particular Timeslot number “2” of “TRx-002” of site “AMITYSCHL1” of “BSC15”. FIELD TEST TRIAL, FOR ALARM 7745: The alarm 7745 shows for this particular cell “SARAIJLNA1” that Timeslot (TS0 & TS1) to be working fine and Timeslots(TS2, TS3,TS4,TS5,TS6, & TS7) not carrying calls(blocked).

Field test was conducted with TEMS for this particular cells at non busy hour and could find that the Mobile could latch on to Time slot TS0 & TS1 only and and the remaining Time slots ( TS2, TS3, TS4, TS5, TS6, & TS7 ) could not get calls going on tending the timeslot Faulty.

ALARM NUMBER 7601:- BCF OPERATION DEGRADED:

This alarm 7601 is generated at the BTS.

BD018 BCF-0030 EQUIPM 2007-07-24 04:20:45.42 ** ALARM (14652) 7601 BCF OPERATION DEGRADED Difference between PCM and base station frequency reference. 02 01 07 96 00 00

I. Fault reason: Cabinet I2C bus is jammed.

Solution: 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

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

Solution: 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.

III. Fault reason: Difference between the PCM and BTS frequency reference.

Solution:

1. Check the synchronisation settings of the transmission interface.( DAC Value)DAC value Range from 1800 t0 2200. 2. If the settings are OK, check the transmission chain. 3. If the alarm stays active or reappears after the recovery actions above, reset the BCF. 4. If the alarm reappears after the BCF reset, replace the BTS. Note: If this Supplementary alarm appears there is Drift in clock value(DAC). That leads to HO failures

IV. Fault reason: Oven oscillator control is close to its margins. The oven

might be outdated.

Solution: 1. Check the synchronisation settings of the transmission interface. 2. If the settings are OK, check the transmission chain. 3. If the alarm stays active or reappears after the recovery actions Above, reset the BCF. 4. If the alarm reappears after the BCF reset, replace the BTS Note: If this Supplementary alarm appears there is Drift in clock value (DAC). That leads to HO failures

V. Fault reason: Flash operation failed in BOI or TRX.

Solution:

1. Replace the BOI. 2. BOI=Base station operation Interface unit 3. If it is TRX change the TRX

Descrpition of Supplementary information:

1-6 XX XX XX XX XX XX 1 2 3 4 5 6

1. Rack (cabinet) number 2. shelf number 3. slot 4. Type of unit

5. unit number 6. subunit number

ALARM NUMBER 7738:- BTS WITH NO TRANSCATIONS

• This alarm helps in finding out that BTS has had no successfully terminated calls, SDCCH or

Transcations GPRS TBF releases during the supervision period. • This alarm is used for supervising the BTS traffic capacity and to indicate

sudden loss of service on BTS level • This is a BTS Specific alarm. • BF=Temporary Block Flows

No SDCCH Transaction

Descrpition of Supplementary information:

01= No successful SDCCH seizures 02 = No successful TCH seizures 03 = 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

NO SDCCH TRANSACTION

• NO GPRS TRANSACTION 2.

NO GPRS

Transaction

Temporary solution: Reset the Sector (BTS) Permanent solution: Replace the Hardware ALARM NUMBER 7604:- BTS OPERATION DEGRADED

Description: Major fault (or faults) has occurred in a unit (or units) that Belong to the sector indicated in the alarm.This alarm belong to particular sector.

• Following are the Fault Reasons for BTS Operation Degraded.

I. Fault Reason: Remote tune combiner temperature is

dangerously high.

Solution: 1. Ensure that the ambient temperature of the base station is within Specified limits. 2. Check the cabinet fans. 3. Replace the remote tune combiner.

II. Fault reason: Remote tune combiner temperature is

low.

Solution: 1. Ensure that the ambient temperature of the base station is within Specified limits. 2. Check the cabinet heater if it is installed. 3. Replace the remote tune combiner.

III. Fault reason: Rx levels differ too much between

main and diversity antennas.

Solution:

1. Check the RSSI measurements by BTS Manager. 2. Locate the cause of the alarm (unit, cable, antennas).Check unit ,

cable and antennas, 3. RSSI: Received Signal Strength indicator. 4. Imp alarm where call gets blocked.

Descrpition of Supplementary information:

1-6 XX XX XX XX XX XX 1 2 3 4 5 6

7. Rack (cabinet) number 8. shelf number 9. slot 10. Type of unit

11. unit number 12. subunit number

This supplementary information is valid for 1 to 3 fault reasons.

IV: Fault Reason: Fault in the chain between power unit and high gain MNxx with. Supplementary information: By pass

ALARM NUMBER 7744:- EXCESSIVE TCH INTERFERNCE

Descrpition: During the supervision period, the TCH time slot has suffered Excessive interference in idle mode that is equal to or higher than the operator-defined alarm threshold percentage.

• That is the ,Interference in the time slot has lasted longer than is

acceptable.

• The interference level classified as excessive is defined by the Operator. The alarm is used to supervise the BTS traffic capacity

• Supplementary information fields

1-8 the percentage (per each TRX time slot) that the channel has Spent in excessive interference during the supervision period. The number is a hexadecimal, 0 - 64 %. If the time slot is not a TCH time slot, the value is 0 9 the threshold level of excessive interference. The values are 0, 1, 2, 3 and 4 10 the TCH channel's alarm threshold percentage of the time spent In excessive interference, 1 - 100 %. The alarm is generated if at least one TRX time slot reaches the threshold

These alarms basically indicate the uplink interfencence, check MAIO, HSN. MAIOSTEP

Check any Repeaters installed near the site, fine tune the repeaters

. ALARM NUMBER 7606:- TRX FAULTY

. Descrpition:

• Critical fault has occurred in a TRX. This alarm blocks the TRX.

• Call drops will be severely with the faulty TRX.

• Following are the Fault Reasons for TRX Faulty. I. .Fault reason: Failure detected during TRX

configuring. Solution: • Either the TRX is faulty or its frequency band is different

from the one that was configured into BSC. Replace the TRX with a functional TRX or with another TRX with correct frequency band.

II. Fault reason: Antenna connection faulty.

Solution:

• Check the antenna and cabling. If the antenna and cabling are faulty, correct the problem and run TRX test to cancel the alarm.

• If the antenna and cabling are OK, TRX is faulty. Replace the faulty TRX.