Soft-Information-Aided Detection Algorithm for V-Blast Systems

The Vertical Bell Laboratories Layered Space-Time (V- BLAST) scheme achieves very high spectral efficiency while maintaining low implementation complexity. However, the error propagation resulting from a wrong cancellation limits the overall system performance greatly. The traditional detection methods proceed assuming that the prior-detected sub-streams are correct at each stage. None of them considers the still existed error propagation. In this paper, we propose a novel soft-information-aided detection algorithm which makes use of the log-likelihood ratio (LLR) information of the prior-detected signals. In this new algorithm, the interference canceling and ordering all take the error propagation effect into consideration, thus making the detection more reliable. We derive the new algorithms for ZF-SIC and MMSE-SIC V-BLAST respectively. Simulation results show that the new proposed algorithms achieve good BER performance compared with the traditional ones.