Optimization of coded layered space-time architecture for OFDM systems

This paper proposes a new approach for coded layered space-time OFDM systems over frequency-selective channels. We start with a comprehensive signal model including error propagations. We derive an improved signal detector in the mean-square-error criterion and the corresponding optimal detection ordering. We also describe the optimal soft bit log-likelihood ratio (LLR) value computation method by taking the decision errors into account for soft-input Viterbi decoder. We compare the proposed scheme with the conventional V-BLAST system and show that significant performance improvement at high data rates can be attained.