Rotated constellation demapper design

    Hi! I have been working on an OFDM demodulator. It uses rotated constellations (Q-delay, just like in DVB-T2) to improve BER performance over frequency selective channels. I am going to share my thoughts about demapping algorithm here and describe some details. You can use MATLAB code to repeat the simulation and check results by yourself.

    Here is a structure of my work:

1. Demapping. LLR calculation.
2. Rotated constellations. Q-delay.
3. Rotated constellation demapper.
1. Direct implemention
2. QRD based demapper