On Site RTWP Trouble Shooting Guide

 

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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 KPI KPIs. s. 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 re receiver ceiver is large largerr 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 RTW RTWP P of  the diversity receiver (or the main receiver) receiver) is normal. Clear the alarm by referring to the method meth od of handling handling a high RTWP RTWP..   — 

−

The RTWP RTWP of the main receiver receiver and R RTWP TWP of the diversity receiver receiver are abnormally high, and the differenc diff erencee between between them is larger larger than 10 dB. Clear the alarm by referring to the method of  handling handli ng a high RTWP TWP..   — 

−

The RTWP RTWP of the main main receive receiverr (or the the diversity diversity receiv receiver) er) is abnor abnormall mally y low low,, but the R RTWP TWP 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: −

−

−

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 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. 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: Trouble Troubleshoot shoot the standing wave-related wave-related problem and clear the high standing wave ratio.

Method of handling high and low RTWP on site:

1.

If the abnorma abnormall RTWP RTWP issue is only appear appear in particul particular ar secto sector(s) r(s) in a Node NodeB, B, res reserve erve the the all the sectors to block user setup service. Start to trace the cell RTWP and recor record d the log. Start to swap the antenna between normal and abnormal sectors and observe the changes in the RTWP changes changes in both sectors.-If the cell RTWP tr trending ending is following the problematic sector antenna, then most probably there is external interference.

2.

Swap back back the antenna antenna to original original state, state, to further confirm confirm exter external nal inter interfere ference, nce, swi swing ng the antenna of the problematic sector and observe the change in RTWP trending.

3.

If the abnormal abnormal RTWP RTWP issue is appear appear in all all sectors sectors in a NodeB, NodeB, check check any o other ther sy system stem integrated with the 3G system. Direct connect the antenna antenna to spectrum analyzer and observe any high abnormal signal.

4.

If step step 3 shows norma normall result, result, then the the issue might might due due to inte internal rnal ffactor actors. s. Pre Prepare pare d dumm ummy y load and connect to RRU and observe the RTWP change. Else, there might be external factor exists.

5.

In majority majority cases cases there there is issue with with connector connector,, cable sharp sharp be bending nding or m may ay be wat water er 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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