Turbo-greedy coding for high data rate wireless communications: principles and robustness

We present a novel iterative-greedy demodulation-decoding algorithm for turbo codes for multiple antenna systems. The decoding algorithm is based on a previously introduced novel greedy detection method for multiuser communications. The iterative-greedy demodulation-decoding algorithm is characterized by the exchange of soft information between the demodulator and the decoder, and the significant decrease in computational complexity, as compared to the standard method of iterative demodulation-decoding, with only a slight degradation in performance. This is due to the novel, greedy method of calculating the log-likelihoods to be used in the iterative decoding process, where only a small subset of the possible received vectors is considered, resulting in a receiver with only polynomial complexity in the number of transmit antennas. Finally, we demonstrate the robustness of the proposed algorithm with respect to channel estimation errors.