Improving BLAST performance using space-time block codes and turbo decoding

An architecture that theoretically achieves channel capacity on multi-input multi-output channels was proposed by Foschini (1996) as BLAST. We show that in practical systems BLAST performance is limited by error propagation. The theoretically possible increase in diversity level during successive detection steps cannot be achieved. We evaluate the possibilities to improve BLAST performance. We first analyze an MMSE solution compared to zero forcing. Furthermore, we show the benefits of soft over hard interference cancellation and propose an iterative turbo detection algorithm. Finally, we apply transmit diversity with space-time block codes to BLAST. This improves the overall diversity level and reduces the number of required receive antennas.