FFT Guide

FFT test guide FFT : Fast Fourier Transformation From RAN13, we can do FFT test to check uplink interference with NodeB LMT. Before doing FFT test, pls monitor RTWP first to make sure RTWP is not good. At RNC LMT, do cell RTWP monitoring.

At the same time, at RNC LMT, do User monitoring. Just at Step 3 select “Cell User Number”.

At NodeB LMT, do cell RTWP monitoring.

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At NodeB LMT, Board RTWP monitoring

Step 1 Run the MMLcommand LST RRU at selected NodeB and get the RRU cabinet No, subtrack No and slot No.

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Step 2 You can find FFT Frequecy Scan at Maintain Tab of NodeB LMT.

There are 3 models of FFT frequecy scan: High-resolution on-line frequency scan, Broadband on-line frequency scan and Broadband off-line frequency scan. Mostly use High-resolution on-line frequency scan and Broadband on-line frequency scan. High-resolution on-line frequency scan Don’t break down service.RBW should be set to 100KHz.

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Broadband on-line frequency scan Don’t break down service.RBW should be set to 200KHz.

Broadband off-line frequency scan Break down service. This will scan all uplink frequency which RRU support. First deactivate cell. RBW should be set to 200KHz. After testing, activate cells. Deactivate cells, Command :DEA UCELL: CellId=*; Activate Cells, Command : ACT UCELL: CellId=*;

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How to check the result with offline tool Step 1 NodeB LMT must be installed at your computer. Now XL NodeB version is WCDMA V200R014C00SPC354. You can get the install file from support.

You can check if the NodeB version is installed or not.

Step 2 Start FreqChart FreqChartReview Tool

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Step 3 Open frequency scan file which type is mmf.

Step 4 Start to review frequency scanning data 2016-9-15

The result will be presented.

Note Rx_Level(dbm)[Index_of_RX_Channel=0]: RX0 channel real time results Rx_Level(dbm)[Index_of_RX_Channel=1]: RX1 channel real time results Total_Rx_Level(dbm)[Index_of_RX_Channel=0]: RX0 channel the max results Total_Rx_Level(dbm)[Index_of_RX_Channel=1]: RX1 channel the max results

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