Hi, I am trying to track how modulated symbols are processed through the precoding operation in the LTE PDSCH signal processing chain. To do this I configured the enb structure, DLSCH and PDSCH using the RMCs available. In the PDSCH, the modulated symbols undergo the Layer mapping operation before undergoing the Precoding operation. I placed temporary counters within the ltePDSCH function to observe the modulated symbols, the layer mapped symbols and the precoded symbols. Now for RMC = 'R.10' the output of the modulator for 16QAM for a codeword length of 80 bits provides a 1 by 1 cell that has 20 by 1 complex array, a layer mapped output of 10 by 2 complex double and the precoder output of 20 by 2 complex double.
For RMC = 'R.10', it uses two antenna ports and that explains why the 20 by 1 becomes a 10 by 2 due to layer mapping. For RMC = 'R.10', it can be applied for spatial multiplexing or transmit diversity and that explains why the 10 by 2 becomes a 20 by 2 since a precoding matrix was applied to it.
The issue is I can't think of a way to find the precoding matrix used within the existing ltePDSCH function used. So can someone help me find a way to determine the precoding matrix used. This is the code I used below:
enb.RC = 'R.10';
enb = lteRMCDL(enb);
[cwout,~] = lteDLSCH_edited(enb,enb.PDSCH,80,enb.PDSCH.TrBlkSizes);
enb.PDSCH.Modulation = '16QAM';
[symbols,tempM,tempP,tempL] = ltePDSCH_edited(enb,enb.PDSCH,cwout);
The tempM, tempP, and tempL are my temporary variables to hold the output of the modulation, precoding and layer mapping operations respectively. I saved the ltePDSCH function in a new file I renamed ltePDSCH_edited. I never edit the original function files from the toolbox.
