Decision-feedback differential demodulation of bit-interleaved coded MDPSK for flat Rayleigh fading channels

A novel simple receiver structure for M -ary differential phase–shift keying (MDPSK) transmission over flat Rayleigh fading channels without channel state information is proposed. We apply convolutional codes for error correction and bit–interleaving as appropriate means to combat the effects of fading. In the decoding the hard decisions of the Viterbi algorithm are fed back to enable a more reliable estimation of the current channel state. A theoretical analysis of the associated cutoff rate for error–free feedback shows remarkable gains in power efficiency compared to conventional differential demodulation, while the computational complexity of the decoding remains low. The results from information theory are in good agreement with the obtained simulation results. The proposed scheme works remarkably well for target bit error rates which are usually of interest.