A reliability-based 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. There have been great efforts focusing on alleviating the error propagation. In detection procedure, however, none of them considers the still existed error propagation in itself, i.e., all these detection methods proceed assuming that the prior-detected sub-streams are correct at each stage. In this paper, we propose a new detection algorithm which makes use of the log-likelihood ratio (LLR) information of the prior-detected signals. In this new algorithm, the interference nulling and canceling all take the error propagation effect into consideration, thus making the detection more reliable. We derive the reliability-based algorithms for ZF-SIC and MMSE-SIC V-BLAST respectively. Simulation results show that the new proposed algorithms achieve more than 2dB gains over the traditional ones both with and without channel coding. The increase of computation complexity is limited.