How To Measure LTE TDD Signal By RFmx LTE/LTE-Advanced

Updated Jul 4, 2024

Environment

Software

  • RFmx LTE/LTE-Advanced 

If you used RFmx LTE/LTE-Advanced to measure one LTE TDD signal with default setting , you could not get the correct result ; How could you set the RFmx panel to measure the LTE TDD signal ? 
Below is one example about how to create one LTE TDD signal by RFmx Waveform Creator :

LTE TDD 2-7 waveform setting1.jpg

LTE TDD 2-7 waveform setting2.jpg

LTE TDD 2-7 waveform setting3.jpg

LTE TDD 2-7 waveform setting4.jpg


The LTE TDD signal have DL/UL configuration as 2:7 , which means the subframes as DSUDD DSUDD; There are two subframes working on PUSCH, subframe1 is QPSK and subframe2 is 16QAM ;

Open RFmx LTE/LTE-Advanced to measure and demodulate the signal with default setting , RFmx could not demodulate it correctly , like below picture :



RFmx LTE default setting for result.jpg



How could you get the correct measurement result ?
 

1.Setting the Trigger mode as Digital Edge (setting SOURCE as PXI_Trig0 which is same as RFSG setting)
   Setting the SYNCHRONIZATION MODE as Marker
digital trigger and maker.jpg
2.To get correct result of ModAcc , you should set the MEASUREMENT OFFSET as 4 Slots for subframe1;
measurement offset 4slots.jpg
You can see the correct constellation result for subframe1 (QPSK).

Of course , when you set  set the MEASUREMENT OFFSET as 14 Slots for subframe2; You also see the expected result about constellation for subframe2 (16QAM);
measurement offset 14slots.jpg

3.To get the correct result of ACP, you should set the correct value of Sweep Time; Change the default value 1.000ms as 10ms; You can see the expected result ;
ACP result.jpg
 
 

RFmx LTE/LTE-Advanced can measure and demodulate the LTE TDD signal success ;



expected result of LTE TDD.jpg
 

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