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RTWP Alarm Troubleshooting When an RF module or the feeder system is faulty, the related alarms are reported. If any of the alarms listed in this section is reported, the RTWP may be abnormal, affecting the service KPIs. KPIs. Therefore, perform troubleshooting according according to the reported alarms: alarms: ALM-26522 RF Unit RX Channel RTWP/RSSI Unbalanced Cause analysis: The alarm is reported if the difference difference between RTWP of the main receiver receiver and RTWP RTWP of the diversity receiver receiver is larger larger than 10 dB. Handling suggestion:
Symptoms of the reported alarm are as follows: −
The RTWP RTWP of the main receiver receiver (or the diversity receiver) is abnormally high, and the RTWP RTWP of the diversity receiver (or the main receiver) receiver) is normal. Clear the alarm by referring to the method method of handling handling a high RTWP RTWP.. —
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The RTWP RTWP of the main receiver receiver and RTWP RTWP of the diversity receiver receiver are abnormally high, and the differenc differencee between between them is larger larger than 10 dB. Clear the alarm by referring to the method of handling handling a high RTWP. TWP. —
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The RTWP RTWP of the main main receive receiverr (or the the diversity diversity receiv receiver) er) is abnormall abnormally y low, low, but the RTWP RTWP of the diversity receiver (or the main receiver) is normal. Clear the alarm by referring to the method of handling handling a low RTWP. TWP. —
ALM-26521 RF Unit RX Channel RTWP/RSSI Too Low Cause analysis: The alarm is reported when the RTWP received on the RF channel is lower than 114 dBm. –
Handling suggestion: −
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The RTWP RTWP of the main receiver receiver or RTWP RTWP of the diversity receiver receiver is abnormally low. low. alarm by referring referring to the method of handling handling a low RTWP RTWP..
—
Clear the
The RTWP RTWP of the diversity receiver receiver is abnormally low. In In the indoor coverage scenario, scenario, the diversity channel may may not be connected to antennas. antennas. If two RF modules are are in the same cabinet, cabinet, the RF interconnection mode mode may be disabled. The RTWP RTWP of the main receiver receiver is abnormally low. low. In the indoor coverage scenario, the RX and TX channels are separated. As a result, no uplink signal is available on the main receiver. receiver. ALM-26532 RF Unit Hardware Fault Cause analysis: The RF channel may be faulty, or the RX channel may be faulty, resulting in abnormal RTWP. Handling suggestion: Perform a soft reset or a hard reset on the RF module to check whether the alarm can be cleared. If no, you are advised to replace the RF module with a required one.
ALM-26752 ALD Hardware Fault Cause analysis: If the TMA gain is invalid in the worst case, services on the RX channel where the TMA resides are disconnected. Handling suggestion: Replace the TMA device.
ALM-26758 TMA Running Data and Configuration Mismatch
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Cause analysis: If the TMA gain or the working mode is inconsistent with the configuration, the uplink TMA gain is abnormal, resulting in RTWP problems. Handling suggestion: Reset the TMA gain or the working mode.
ALM-26755 TMA Bypass Cause analysis: The TMA gain is invalid. As a result, the uplink sensitivity decreases, the sector coverage narrows, and the cell RTWP (background noise) decreases. Handling suggestion: Check whether the TMA is faulty. If yes, replace the TMA with a required one. If no, set the TMA working mode to be normal.
ALM-26757 RET Antenna Running Data and Configuration Mismatch Cause analysis: The tilt angle of the antenna is inconsistent with the configured value, resulting in faulty uplink and downlink coverage. In this case, the cell service and the RTWP may be abnormal. Handling suggestion: Reset the tilt angle of the antenna.
ALM-26541 ALD Maintenance Link Failure Cause analysis: If the TMA maintenance links are disconnected, the cell uplink gain may be abnormal, resulting in the decrease of the RTWP background noise. Handling suggestion: Check the TMA for the maintenance links. If the links cannot be restored, replace the TMA device.
ALM-26529 RF Unit VSWR Threshold Crossed Cause analysis: When a standing wave-related alarm is reported, especially in the case of high standing wave ratio, the feeder may be faulty. The problem may be caused by a broken feeder. Handling suggestion: Troubleshoot the standing wave-related problem and clear the high standing wave ratio.
Method of handling high and low RTWP on site:
1.
If the abnormal RTWP issue is only appear in particular sector(s) in a NodeB, reserve the all the sectors to block user setup service. Start to trace the cell RTWP and record the log. Start to swap the antenna between normal and abnormal sectors and observe the changes in the RTWP changes in both sectors.-If the cell RTWP trending is following the problematic sector antenna, then most probably there is external interference.
2.
Swap back the antenna to original state, to further confirm external interference, swing the antenna of the problematic sector and observe the change in RTWP trending.
3.
If the abnormal RTWP issue is appear in all sectors in a NodeB, check any other system integrated with the 3G system. Direct connect the antenna to spectrum analyzer and observe any high abnormal signal.
4.
If step 3 shows normal result, then the issue might due to internal factors. Prepare dummy load and connect to RRU and observe the RTWP change. Else, there might be external factor exists.
5.
In majority cases there is issue with connector, cable sharp bending or may be water seepage in feeder cable, identify the effected cable with the help of LMT real time monitoring and perform detail health check on cable (remake connector).
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Real time monitoring of RTWP by LMT:
Login to LMT and follow below steps to monitor the real time RTWP.
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