ALM-4122 Radio link prompt alarm

Description

This alarm is reported when the BTS detects continuous RL abnormalities. RL abnormalities include the following situations: a.Warning for abnormal channel activation. It indicates that the channel types or channel states between BTS and BSC are not consistent. b.Warning for abnormal channel release. It indicates that the proportion of abnormal channel release exceeds the relevant alarm threshold. c.Warning for no traffic. It indicates that there is no traffic detected on the TRX within the specified time. d.Warning for power level imbalance between uplink and downlink. It indicates that the uplink power level and the downlink power level deviate from each other greatly.

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 Value range: 0-2047
2	Board Type	Number of the type which the faulty board belongs to. 65:DTRU/GTRU/DDRM 88:DRRU 92:DRFU 96:MRRU 100:MRFU 101:GRFU 102:GRRU 151:QTRU
3	Board No.	Number of the fault board
4	PassNo	Number of the passage where the faulty board 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 board or module is located 0-2047: Cell index of the faulty cell in the data configuration 65535: None
7	Site Type	Type of the site where the faulty board 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 is located.
9	BoxNo	Number of the subrack where the faulty board is located.
10	SlotNo	Number of the slot where the faulty board is located.
11	Site Name	Site Name
12	Alarm Attribute	Alarm Character 0:Normal 1:Transient Count

Impact on the System

Abnormal channel activation alarm (Sub No.00):
If the channel types or states between the BSC and BTS are not consistent, the BTS might respond with a channel activation failure or not respond at all. This will bring about a call failure and directly affect the traffic statistic specifications.
Abnormal channel release alarm (Sub No.01):
When the uplink or downlink is faulty, there is no correct interaction on the radio interfaces. When a channel is activated, there will be no normal communication on the channel on the Um interface. Finally the BSC will release the channel.
No traffic alarm (Sub No.02):
When the DTRU that carries the primary BCCH is faulty in the downlink, the downlink CCCH will become unavailable and there will be no access or handover to the relevant cell. When the DTRU that carries the primary BCCH in an isolated BTS is faulty in the uplink, the uplink CCCH will become unavailable and there will be no access to the cell while no handover is supported.
Power level imbalance between uplink and downlink alarm (Sub No.03):
A fault or defect in the uplink receive channel or downlink transmit channel on the BTS side will directly affect the traffic statistic specifications: -A fault or defect in the downlink transmit channel of the DTRU that carries the primary BCCH will reduce the cell coverage area and lower the cell traffic load.
-A fault or defect in the downlink transmit channel of the DTRU that carries a non-primary BCCH will reduce the coverage area, lower the handover success ratio and cause failure if the channel is assigned to the DTRU.
-A fault or defect in the uplink receive channel of the DTRU that carries the primary BCCH will reduce the traffic load within the cell coverage area and lower the handover success ratio.
A fault or defect in the uplink receive channel of the DTRU that carries a non-primary BCCH will lower the handover success ratio and cause failure if the channel is assigned to the DTRU.

System Actions

The system starts auto detection after the alarm is generated. The alarm will disappear when the conditions are met.

Possible Causes

The channel types or states between the BSC and BTS are not consistent.
The proportion of abnormal channel release exceeds the relevant alarm threshold.
The DTRU has not detected traffic for a defined time period.
Great difference for the same call between the uplink receive power level detected by the BTS and the downlink receive power level reported from the MS.

Procedure

Check the alarm sub-category number (Sub No.).
1. If the alarm tributary number is 0, go to procedure 2.
2. If the alarm tributary number is 1, go to procedure 3.
3. If the alarm tributary number is 2, go to procedure 4.
4. If the alarm tributary number is 3, go to procedure 5.
Check whether the channel configuration and the current channel status on the BSC side are consistent with those on the BTS side.
1. Check the channel configuration on the BSC side.
2. Check the channel configuration on the BTS side.
3. Check whether the channel configuration and the current channel status on the BSC side are consistent with those on the BTS side.
  Y => Consistent. Contact Huawei Customer Service Center.
  N => Inconsistent. Go to step d.
4. Change the channel status and channel type of the BTS. Then, check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  N => The alarm is not cleared. Contact Huawei Customer Service Center.
Check for the interference and improper data configuration.
1. Check the traffic measurement counters for interference.
  Y => The interference exists. Go to step b.
  N => The interference does not exist. Go to step c.
2. Contact Huawei Customer Service Center to eliminate the interference. Then, check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  N => The alarm is not cleared. Go to step c.
3. Check the traffic statistics counter "Cell Performance Measurement: Random Access Performance Measurement". Check whether the difference between "Random Access Performance Measurement > Immediate Assignment Requests" and "Random Access Performance Measurement > Immediate Assignment Successes" is greater than 400.
  Y => The difference is greater than or equal to 400. You can infer that the radio link alarm is caused by the abnormal SDCCH release. Go to step b.
  N => The difference is less than 400. Go to step d.
4. Optimize the radio resource parameters that are related to random access.
  The related parameters are RXLEV ACCESS MIN, Cell Reselection Hysteresis (CRH), and TRX Static Power Level.
  
  After the parameter optimization, check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  N => The alarm is not cleared. Go to step c.
5. Check whether the abnormal TCH release occurs.
  Y => Go to step d.
  N => Go to step g.
6. Handle the abnormal TRX TCH release. Check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  N => The alarm is not cleared. Go to step g.
7. Reset the TRX. Check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  N => The alarm is not cleared. Go to step h.
8. Replace the TRX. Check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  N => The alarm is not cleared. Contact Huawei Customer Service Center.
Check the site and related engineering connections.
1. Check whether the site is a new site without subscribers.
  Y => The site is a new site without subscribers. In this case, the alarm handling is not necessary.
  N => The site is not a new site. Go to step b.
2. Check the connections between the jumper and the duplexer, between the jumper and the feeder, between the jumper and the surge protection unit, and between the jumper and the antenna.
  Y => All the connections are good. Go to step d.
  N => A connection is not secured. Go to step c.
3. Tighten the loosened connectors. Then, check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  N => The alarm is not cleared. Go to step d.
4. Check whether the water leaks into the connectors between the jumper and the duplexer, between the jumper and the feeder, between the jumper and the surge protection unit, and between the jumper and the antenna.
  Y => There is water leakage. Go to step e.
  
  N => There is no water leakage. Contact Huawei Customer Service Center to handle the alarm.
5. Block the cell.
6. Replace the connector where water leakage occurs and conduct waterproof protection on the new connector in compliance with related engineering standards.
7. Unblock the cell. Check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  N => The alarm is not cleared. Contact Huawei Customer Service Center.
Check for related alarms and check the modules and cables.
1. Check whether ALM-5326 Level 1 VSWR Alarm is reported on the LMT.
  Y => The alarm is reported on the LMT. Go to step b.
  N => The alarm is not reported. Go to step c.
2. Rectify the fault according to handling suggestions in ALM-5326 Level 1 VSWR Alarm. Check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  
  N => The alarm is not cleared. Go to step c.
3. Reset the DUP Unit. Check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  N => The alarm is not cleared. Go to step d.
4. Check the connections between the jumper and the duplexer, between the jumper and the feeder, between the jumper and the surge protection unit, and between the jumper and the antenna.
  Y => All the connections are good. Go to step j.
  N => A connection is not secured. Go to step e.
5. Tighten the loosened connectors. Then, check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  N => The alarm is not cleared. Go to step f.
6. Check whether the water leaks into the connectors between the jumper and the duplexer, between the jumper and the feeder, between the jumper and the surge protection unit, and between the jumper and the antenna.
  Y => There is water leakage. Go to step g.
  
  N => There is no water leakage. Go to step j.
7. Block the cell.
8. Replace the connector where water leakage occurs and conduct waterproof protection on the new connector in compliance with related engineering standards.
9. Unblock the cell. Check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  N => The alarm is not cleared. Go to step j.
10. Replace the DDPU/DDPM/DFCU. Check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  N => The alarm is not cleared. Go to step k.
11. Measure the VSWR by using the related instrument at the antenna port of the duplexer. Locate whether the fault occurs on the jumper, surge protector, feeder, TMA, or the antenna.
12. Replace the faulty component. Check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  N => The alarm is not cleared. Go to step m.
13. Reset the TRX. Check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  N => The alarm is not cleared. Go to step n.
14. Replace the TRX. Check whether the alarm is cleared.
  Y => The alarm is cleared. The alarm handling is complete.
  N => The alarm is not cleared. Contact Huawei Customer Service Center.