A decision directed coherent detector for OFDM

A coherent decision directed detector for orthogonal frequency division multiplexing (OFDM) is proposed and analyzed. The modulator uses differential encoded signalling over a multipath frequency selective Rayleigh fading channel. The detector employs a decision directed linear minimum mean square error (LMMSE) estimator of the channel gain on each subchannel. The main idea is to explore the correlation between the subchannels in order to obtain a good channel estimate. The proposed LMMSE based detector is shown to be significantly better than a standard differential channel estimator.