alm-4122 radio link prompt alarm

6/11/2014 M2000 Online Help

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ALM-4122 Radio Link Prompt Alarm

Description

The BTS checks for TRX- and channel-level service faults according to the TRX signaling messages. This alarm is reported when a service fault is detected.

This alarm has multiple tributaries, each of which has its own determining algorithm and related parameters. For details, see the help for the SETGTRXRLALM command. Descriptions for each tributary are as follows:

Tributary 0: Abnormal Channel Activation Alarm

Tributary 0 indicates that the configured channel status for the BTS is inconsistent with that for the BSC. The alarm with tributary 0 is reported when theBTS responds to the BSC with a channel activation failure message five consecutive times for the same channel.

Tributary 1: Abnormal Channel Release Alarm

Tributary 1 indicates normal link setups and abnormal link releases over the Um interface, evaluating the quality of uplink and downlink channels over theUm interface.

The alarm with tributary 1 is reported when the ratio of the number of abnormal releases for a channel to the number of times the channel is occupiedreaches Abnormal Warn Threshold. This alarm is cleared when this ratio returns to below Abnormal Release Threshold.

Total number of times a channel is occupied = Abnormal Release Statistic Base x Number of subchannels

Tributary 1 has three parameters: Abnormal Release Statistic Base, Abnormal Warn Threshold, and Abnormal Release Threshold.

Tributary 2: No Traffic Alarm

Tributary 2 monitors traffic of a TRX for a certain period to determine whether a channel is occupied.

The alarm with tributary 2 is reported when the no-traffic period on the TCH, SDCCH, and PDCH reaches Statistical Period of No-traffic during a detectionperiod from Begin Time of WLA Detection to End Time of WLA Detection.

Tributary 2 has three parameters: Begin Time of WLA Detection, End Time of WLA Detection, and Statistical Period of No-traffic. By default, thedetection period is from 08:00 to 22:00 and the statistical period of no traffic is 4 hours.

Tributary 3: Power Level Imbalance Between Uplink and Downlink Alarm

Tributary 3 indicates whether the RX level between the uplink and downlink channels is inconsistent.

The BTS obtains the uplink and downlink RX level from measurement reports and implements power compensation. If the difference of the RX level betweenthe uplink and downlink channels is outside the range of [Up Down Balance Basic Difference - Up Down Balance Floating Range, Up Down Balance BasicDifference + Up Down Balance Floating Range], the power level is imbalanced between the uplink and downlink channels. The alarm with tributary 3 isreported when the ratio of the number of measurement reports indicating power level imbalance to the total number of measurement reports reaches thevalue of Up Down Balance Alarm Threshold.

Tributary 3 has three parameters: Up Down Balance Basic Difference, Up Down Balance Floating Range, and Up Down Balance Alarm Threshold.

Attribute

Alarm ID Alarm Severity Alarm Type



4122 Warning Fault

Parameters

ID Name Meaning

1 Site No. Number of the site where the faulty board or module is located

0-2047: Number of the faulty site in data configuration

2 Board Type Number of the type of the board or module that is faulty

65: DTRU/GTRU/DDRM

88: DRRU

92: DRFU

96: MRRU

100: MRFU

101: GRFU

102: GRRU

151: QTRU

3 Board No. Number of the faulty board or module

4 PassNo Number of the passage where the faulty board or module is located

5 SubLink No. Alarm sub-category number

0: Abnormal channel activation alarm

1: Abnormal channel release alarm

2: No traffic alarm

3: Power level imbalance between uplink and downlink alarm

6 Cell Index Index of the cell where the faulty board or module is located

0-2047: Cell index of the faulty cell in data configuration

65535: None

7 Site Type Type of the site where the faulty board or module is located

12: BTS3012;

13: BTS3006C;

14: BTS3002E;

15: BTS3012AE;

16: BTS3012 II;



17: DBS3900 GSM;

18: BTS3900 GSM;

19: BTS3900A GSM;

8 RackNo Number of the rack where the faulty board or module is located

9 BoxNo Number of the subrack where the faulty board or module is located

10 SlotNo Number of the slot where the faulty board or module is located

11 Site Name Name of the site

12 Alarm Attribute Alarm attributes

0: Normal

1: Transient Count

Impact on the System

The impacts on services of each tributary are as follows:

1. Tributary 0: Abnormal Channel Activation Alarm

Channel activation fails. The number of call and handover failures increases on the TRX.

2. Tributary 1: Abnormal Channel Release Alarm

The success rate of channel assignments is low. There is a high probability of call and handover failures on the TRX.

3. Tributary 2: No Traffic Alarm

Radio channels on the TRX are not occupied.

There are two scenarios for this tributary:

(1) No users in the cell are being served by the TRX and the channels are idle. In this case, this alarm does not affect services.

(2) Users in the cell served by the TRX cannot use services. In this case, handle this alarm immediately because the TRX is out of service.

4. Tributary 3: Power Level Imbalance Between Uplink and Downlink Alarm

There is an RX level imbalance between the uplink and downlink channels of the TRX.

If the downlink RX level is low, the cell coverage area of the BCCH TRX may shrink and non-BCCH TRXs may experience a low success rate of channelassignments or a high call drop rate.

If the uplink RX level is low, some users served by the BCCH TRX that are on the edge of the cell may not be able to use services even when downlinksignals are available, and non-BCCH TRXs may experience a low success rate of channel assignments or a high call drop rate.

System Actions



The alarm is automatically cleared when the fault in the radio link has been rectified.

Possible Causes

Tributary 0: Abnormal Channel Activation Alarm

Abnormal conversion of channel types. The channel type or channel status on the BSC side is inconsistent with that on the BTS side.

BTS or BSC software faults. The channel type or channel status on the BSC side is inconsistent with that on the BTS side.

The TRX version is not consistent with the TMU version.

Tributary 1: Abnormal Channel Release Alarm

Uplink or downlink interference

Antenna channel fault

RF channel fault on the TRX module

Transmission fault

Software fault on the TRX module

Tributary 2: No Traffic Alarm

Incorrect data configuration





Engineering issues

No user served by the TRX (no action required)

Tributary 3: Power Level Imbalance Between Uplink and Downlink Alarm




Inconsistency between the configured TMA data and the actual TMA connections


Workflow

If the alarm with tributary 0 is reported, see the handling procedure shown in Figure 1.






Figure 1 Abnormal Channel Activation Alarm

Figure 2 Abnormal Channel Release Alarm



Figure 3 No Traffic Alarm



Figure 4 Power Level Imbalance Between Uplink and Downlink Alarm



Procedure

1. View the Specific Problem parameter of the alarm remotely.

a. View the Specific Problem parameter in the detailed alarm information.

In the case of tributary 0, go to step 2.




2. To clear the alarm with tributary 0, perform the following steps:

a. Check the data configuration.

Run the MML command LST GCELLBASICPARA to check whether the switch SDCCH Dynamic Allocation Allowed is turnedon.

Run the MML command LST GTRXDEV to check whether the switch TCH Rate Adjust Allow is turned on.

If the switches are turned on, turn them off. Then, perform dialing tests on each channel that reports the channel activation failure.Check whether the alarm is cleared.

Y => The alarm is cleared. No further action is required.

N => The alarm persists. Restore the data configuration. Go to step b.

b. Reset the TRX remotely.

Run the MML command RST TRX remotely to perform a soft reset on the TRX. After the TRX startup is complete, perform dialingtests on the faulty channel according to the instructions in step 5. Check whether the alarm is cleared.


N => The alarm persists. Go to step c.

c. Perform a level-4 BTS reset.

Run the MML command RST BTS to perform a level-4 BTS reset interrupts BTS services for about 5 minutes. Therefore, performthis operation during low-traffic hours. After the BTS startup is complete, perform at least six dialing tests on each channel of thefaulty TRX. Check whether the alarm is cleared.


N => The alarm persists. Contact Huawei Customer Service Center.

3. To clear the alarm with Tributary 1, perform the following steps:

a. Check whether the correlated alarms are reported.

Check for correlated alarms, including hardware alarms, transmission alarms, and clock alarms. Clear any alarms according to the

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instructions in the alarm reference. Check whether the alarm is cleared.


N => The alarm persists. Go to step b.

b. Check the data configuration.

If multiple cells use a frequency hopping (FH) group in RF FH, the mobile allocation index offset (MAIO) of each cell must beunique.

Configure adequate SDCCHs or enable the dynamic SDCCH conversion function for the cells on the edge of a location area wherefrequent location updates may occur.

Check whether the alarm is cleared.



c. Check for interference.

View the traffic counters to verify the uplink interference of the channel and the uplink/downlink RX quality. Change the ARFCN forany the TRX that is severely interfered. Check whether the alarm is cleared.


N => The alarm persists. Go to step d.

d. Reset the TRX module.

Run the MML command RST TRX on the LMT to reset the faulty TRX. After the TRX startup is complete, Check whether the alarmis cleared.


N => The alarm persists. Go to step e.

e. Perform a level-4 BTS reset.

Run the MML command RST BTS to perform a level-4 BTS reset interrupts BTS services for about 5 minutes. Therefore, performthis operation during low-traffic hours. After the BTS startup is complete, perform dialing tests on the faulty TRX. Check whether thealarm is cleared.


N => The alarm persists. Go to step f.

f. Replace the faulty TRX module. Check whether the alarm is cleared.








Check for correlated alarms, including hardware alarms, transmission alarms, and clock alarms. Clear any alarms according to theinstructions in the alarm reference. Check whether the alarm is cleared.



b. Check the data configuration.

Run the MML command LST GCELLIDLEBASIC to view the status of the Cell Bar Access switch. If it is set to YES, change it toNO.

If the TRX is not configured with either the SDCCH or TCH, set the channel type of one of the TRX's timeslots to SDCCH or TCH,and then perform dialing tests on the TRX. Check whether the alarm is cleared.



c. If a repeater is deployed onsite and its ARFCN settings are different from those of the BTS, modify the ARFCN settings on eitherthe repeater or BTS so that they are consistent. Check whether the alarm is cleared.



d. Reset the TRX module.

If all of the TRXs in a cell report this alarm, run the MML command RST GCELL to reset the cell. Check whether the alarm iscleared.

If only some TRXs in a cell report this alarm, run the MML command RST TRX to reset the TRXs involved. Check whether thealarm is cleared.



e. Perform a level-4 BTS reset.

Run the MML command RST BTS to perform a level-4 BTS reset interrupts BTS services for about 5 minutes. Therefore, performthis operation during low-traffic hours. After the BTS startup is complete, perform dialing tests on the faulty TRX. Check whether thealarm is cleared.


N => The alarm persists. Go to step f.

NOTE:The alarm with tributary 2 (No Traffic Alarm) can be detected after the detection period. Therefore, wait a little while after resettingthe TRX or performing a level-4 BTS reset, and then check for the alarm. For details about the detection period, see Description inthis section. If allowed, perform dialing tests to verify that the fault has been rectified.



f. Check for antenna faults.

If only some TRXs under an antenna report this alarm, go to step g.

If all of the TRXs under an antenna report this alarm, go to step h.

g. Check for faults on the RF front module or RF unit.

If all of the faulty TRXs are located on the same RF front module, replace the module. Check whether the alarm is cleared.

If all of the faulty TRXs are located on the same TRX module, replace the TRX module. Check whether the alarm is cleared.



h. Switch the antenna system.

If the BTS controls multiple cells, switch the antenna system between the faulty cell and a functional cell. Check whether the TRXof the functional cell reports the same alarm.

Y => The TRX of the functional cell reports the same alarm. Troubleshoot the faults on the antenna system.

N => The TRX of the faulty cell reports the alarm. Contact Huawei Customer Service Center.



Check for correlated alarms, including hardware alarms and antenna alarms. Clear any alarms according to the instructions in thealarm reference. Check whether the alarm is cleared.



b. Check the connections between the RF unit and the jumper.

Reconnect the jumper to the antenna connector of the RF unit. If two RF units are configured for the same cell, disconnect andreconnect the interconnection jumper between them. Then, perform dialing tests and Check whether the alarm is cleared.



c. Reset the TRX module.

Run the MML command RST TRX on the LMT to reset the faulty TRX. After the TRX startup is complete, Check whether the alarmis cleared.



d. Perform a level-4 BTS reset.

Run the MML command RST BTS to perform a level-4 BTS reset interrupts BTS services for about 5 minutes. Therefore, perform





this operation during low-traffic hours. After the BTS startup is complete, perform dialing tests on the faulty TRX. Check whether thealarm is cleared.



e. Check for antenna faults.

If only some TRXs under an antenna report this alarm, go to step f.

If all of the TRXs under an antenna report this alarm, go to step g.

f. Check for faults on the RF front module or RF unit.

If all of the faulty TRXs are located on the same RF front module, replace the module. Check whether the alarm is cleared.

If all faulty TRXs are located on a TRX module, replace the TRX module. Check whether the alarm is cleared.



g. Switch the antenna system.

If the BTS controls multiple cells, switch the antenna system between the faulty cell and a functional cell. Check whether the TRXof the functional cell reports the same alarm.

Y => The TRX of the functional cell reports the same alarm. Troubleshoot the faults on the antenna system.

N => The TRX of the functional cell does not report the alarm. Contact Huawei Customer Service Center.

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alm-4122 radio link prompt alarm

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