Near-optimal symbol-by-symbol detection schemes for flat Rayleigh fading

The optimal MAP detection algorithm for demodulation of M-QAM signaling in the frequency flat Rayleigh fading channel is proposed. A recursive structure is derived which allows for symbol-by-symbol data decisions to be made in an efficient manner. Decision feedback and thresholding are used to reduce complexity which allows for higher order modulations such as 16-QAM to be implemented. Results show that the algorithms presented exhibit favorable advantages over pilot symbol assisted modulation techniques in performance, bandwidth efficiency and required decoding delay. Results for diversity combining techniques are also presented