A Universal Decision Feedback Based Receiver for the Flat Fading Channel

A decision feedback based receiver for correlated fading channels with unknown state is presented in this paper. It is shown that LDPC codes have both capacity approaching performance and universal performance with this receiver on fading channels. The fundamental idea is to decompose a fading channel into a bank of memoryless sub-channels with partially known state, then successively decode them. The receiver of each sub-channel consists of an optimal estimator followed by a memoryless channel decoder. The coding scheme translates the near capacity achieving performance of codes and decoders designed for memoryless channels to channels with memory. The successive decoding approach used in this paper is efficient and optimal. It is also robust against decision feedback errors when sub-channels use a long code. Simulations show a universal performance of within 1 dB of the channel capacity upper bound regardless of the fading rate.