Universal trellis codes for diagonally layered space-time systems

Foschini´s diagonally layered space-time transmission system known as D-BLAST is an architecture designed for a Rayleigh fading environment using multiple element antenna arrays at both the transmit and receive sites to achieve very high spectral efficiencies. In this paper, we propose a simple coding technique for D-BLAST that uses a single trellis code with finite-traceback Viterbi decoding. We examine the performance of universal trellis codes that are designed to have a distance structure that is matched to the periodic signal-to-noise ratio (SNR) variation of the channel created by D-BLAST, under the assumption that the channel is static during one burst but may change from burst to burst. We show that a universal 64-state trellis code on a 2×2 D-BLAST system with long enough block lengths displays universal behavior working on almost every 2×2 channel with at least the mutual information required by a standard 64-state AWGN trellis code. The only 2×2 channel where more mutual information is required is a certain rotation of the zero eigenvalue channel. We also present 4×4 and 8×8 examples.