ALM-2134 Radio Link Alarm

Description

The BTS3X reports this warning in one of the following cases: The channel types or states in the BSC are not consistent with that in the BTS. The proportion of abnormal radio channel release exceeds the relevant alarm threshold. No traffic load is detected on the TRX that carries the primary BCCH within the specified time. The uplink power level detected by the BTS is greatly different from the downlink power level reported by the mobile station (MS).

Attribute

Alarm ID	Alarm Severity	Alarm Type
2134	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. 135:TRX
3	Board No.	Number of the fault board 0:TRX 0
4	PassNo	Number of the passage where the faulty board is located.
5	SubLink No.	Alarm sub-category number 0:warning for abnormal channel activation. It indicates that the channel types or channel states between BTS and BSC are not consistent. 1:warning for abnormal channel release. It indicates that the proportion of abnormal channel release exceeds the relevant alarm threshold. 2:Warning for no traffic on primary BCCH. It indicates that there is no traffic detected on the primary BCCH within the specified time. 3: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.
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 or module is located 3: BTS30 5: BTS312 10: BTS3012A 11: BTS3006A
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

The radio connection performances of the involved TRX will be affected temporarily, as described below:
warning for abnormal channel activation (sub-category 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.
warning for abnormal channel release (sub-category 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.
warning for no traffic on primary BCCH (sub-category 02)
When the TRX 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 TRX 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.
warning for power level imbalance between uplink and downlink (sub-category 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 TRX 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 TRX 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 TRX.
A fault or defect in the uplink receive channel of the TRX 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 TRX that carries a non-primary BCCH will lower the handover success ratio and cause failure if the channel is assigned to the TRX.

System Actions

None.

Possible Causes

warning for abnormal channel activation (sub-category 00)
The channel types or states between the BSC and BTS are not consistent.
A TRX detects an channel activation alarm based on timeslot. It detects each channel for such an alarm. Because channel types and states are configured and managed in timeslots, the number of abnormal channel activation events are calculated in timeslots. One timeslot can be configured as a channel of different types and the number of sub-channels is different. Therefore, the alarm trigger threshold for the number of abnormal channel activation events on a specific timeslot depends on the channel configuration.
Specifically, the threshold is 5 for the number of abnormal activations of each sub-channel. Therefore, the threshold is 5 for the number of abnormal activations of TCH/F channels. The threshold is 10 for the number of abnormal activations of TCH/H channels and 40 for that of abnormal activations of SDCCH8.An abnormal channel activation alarm is reported concerning TRX information. Once an abnormal channel activation is detected on a timeslot, an abnormal channel activation warning involving TRX information shall be reported.
warning for abnormal channel release (sub-category 01)
The proportion of abnormal channel release exceeds the relevant alarm threshold.
Upon receipt of the RELEASE COMPLETE message, a TRX first detects whether there is any interaction on the channel on the Um interface since the channel activation. If no, it shall consider this release as an abnormal release. Then the number of abnormal channel releases is incremented by 1 on the timeslot. If the number of channel activations on the timeslot exceeds the defined alarm threshold (20 for each sub-channel on a timeslot by default, configurable) and the percentage of the number of abnormal releases to the latest defined number of calls reaches or exceeds the defined alarm report threshold (80% by default, configurable), the corresponding TRX shall send the TMU a log containing the channel type of the timeslot. At the same time, it shall report an abnormal channel release warning concerning the TRX information. Otherwise, the percentage of the number of abnormal channel releases will decrease. When this percentage decreases to or below the defined alarm removal threshold (50% by default, configurable), indicating the warning is cleared, the TRX shall check whether the abnormal channel release warning on all the timeslots is cleared. If yes, it shall send the TMU the removal of the abnormal channel release warning.
The alarm threshold for the number of abnormal channel releases on each timeslot depends on the channel type of the timeslot. Specifically, the threshold is in direction proportion to the number of sub-channels on each timeslot. The default alarm threshold for the number of sub-channels on each timeslot is 20. You may also configure it through the BSC maintenance system. The alarm threshold for the number of abnormal channel releases on each timeslot is equal to the number of sub-channels on the timeslot multiplied by the defined threshold for the number of abnormal releases of a sub-channel.
warning for no traffic on primary BCCH (sub-category 02)
If a TRX has not detected traffic for a defined time period (four hours by default, configurable), it shall report a warning for no traffic on the primary BCCH.
warning for power level imbalance between uplink and downlink (sub-category 03)
When a TRX detects a fault or defect in the uplink receive channel or downlink transmit channel, there will be a 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. This difference is called power level imbalance between uplink and downlink. The TRX reports a warning for power level imbalance between uplink and downlink upon detecting a severe imbalance. This warning is one of radio link warnings and identified by alarm sub-category number.
Specifically, the TRX starts to detect such power level imbalance between uplink and downlink since the system time of 22:00. It reports a warning for power level imbalance between uplink and downlink when the total number of measurements reaches 1000 and the percentage of the number of measurements with power level imbalance to the total number reaches the defined alarm threshold. The default value of the threshold is 80%. You may configure a different value through the BSC maintenance system.

Procedure

Check whether there is any correlated alarm.
Check whether ALM-2120 Radio Link Critical Alarm exists in the LMT. If yes, clear ALM-2120 Radio Link Critical Alarm according to the corresponding handling suggestions. Check whether the alarm is cleared.

Y=> The alarm handling ends.

N=> Go to Step 2.
Originate calls on the main BCCH.
Originate calls on the main BCCH and check whether the alarm is cleared.

Y=> The alarm is cleared. Alarm handling is completed.

N=> The alarm is not cleared. Go to Step 3.
Reset the board.
Reset the board and check whether the alarm is cleared.

Y=> The alarm is cleared. Alarm handling is completed.

N=> The alarm is not cleared. Go to Step 4.
Replace the TRX
Replace the TRX and check whether the alarm is cleared.

Y=> The alarm handling ends.

N=> Huawei Customer Service Center.