OFDM Subcarrier Parsing

[Al Amiri, Wesam (waalamiri42)]

Hello, 

I am working on OFDM TX and RX using GNURadio and N210 USRPs. The OFDM implementation is already exists and it works perfectly. 

I am trying to pick or extract some of the subcarriers (or multi-tone) to do some phase measurements on some of the extracted subcarriers. 
This should be done after the demodulation. As depicted in the attached figure, it should be after the FFT of the payload and before the OFDM frame equalizer. 
The problem that I am facing now, is how to extract these subcarriers?
I found something called Subcarrier Parser in Matlab Simulink (https://www.mathworks.com/help/wireless-hdl/ug/hdlofdmreceiver.html), but I could not find a description about its implementation.  

Regards,
Wesam

Screenshot from 2022-11-18 11-52-58.png
Description: Screenshot from 2022-11-18 11-52-58.png