How to troubleshoot RTWP issue

Jake Zhang

3 Jul 2013

What is RTWP alarm?

RTWP: Received Total Wideband PowerIt stands for the uplink load level. The higher the value is , the greater the uplink load level is. RTWP alarm occurs only in 3G cells.

When 3G RRU detects the RTWP value of either main or diversity branch is below -112dBm, it will report a alarm named “RTWP abnormal(198093864) “ .

Generally speaking, if a RTWP alarm is triggered, it means the 3G RRU may be hardware faulty. However the TMA is configured for that sector, a few steps have to be taken before we made the decision to replace that 3G RRU.

What factors will impact RTWP value?Case 1: When TMA is configured, the RTWP value will be changed no matter the

TMA AISG link is broken or not. Reported RTWP value = Measured RTWP value – TMA uplink gain + Uplink

Attenuation

Case 2: When TMA is not configured, RTWP value will not be changed by the “Uplink Attenuation” in the sheet “Rfcable”. That is to say, “Uplink Attenuation” is ignored in this case.

Sheet TMA Sheet RfCable

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How to address the RTWP issue?Check “TMA” sheet in OMCB configuration management:

Case 1: with TMA configured.1. Check if the TMA is connected.(No TMA alarm) If the TMA is not connected, please scan it again. If TMA cannot be scanned, delete

it. If it can be scanned, check the AisgDevice configuration and reconfigure it.2. Make sure the working mode of TMA is “Normal” instead of “Bypass”. If the working

mode is bypass, change it to “Normal”3. Query the gain value of TMA and check it against the actual setting “Uplink Gain” in

sheet “TMA”. Make sure they are the same.4. Check “Uplink Attenuation” in sheet “RfCable” and check TP of this site. If the value

is 0.5 dBm and RRU is not installed near the tower, you should obtain the value from RF team.

5. Check the RTWP value of RRU. If the value is lower than -112, it means that the RRU is faulty and needs to be replaced.

6. On site check. Before you replace the RRU, check if there is any existing TMA installed but not configured. If there is one, please remove it in case the feeder length is less than 50 m.

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How to address the RTWP issue?

Case 2: without TMA configured.1. Check the RTWP value of RRU. If the value is lower

than -112, it means that the RRU is faulty and needs to be replaced.

2. On site check. Before you replace the RRU, check if there is any

existing TMA installed but not configured. If there is one, please remove it in case the feeder length is less than 50 m.

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How to query/set working mode of TMAOMCB configuration management->AISG centralised management->Query AISG device

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How to query the gain of TMA

• OMCB configuration management->AISG centralised management->Query AISG device

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How to obtain the reported RTWP value?

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Method 1:1. Telnet the CC card ( 192.254.1.16 or 10.32.X.X ) 2. Telnet the RRU which reported a RTWP alarm. ( 200.254.0. [RackNo.] ) 3. Input rssi and check the RTWP value.(Ch0 for Rx port 1, Ch1 for Rx Port 2)

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How to obtain the reported RTWP value?

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Method 2: 1. Enter EOMS. Click the menu button to enter PMS. 2. Create measurement task and start it.

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How to obtain the reported RTWP value?

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