Downlink multiuser capacity of interference-limited MIMO systems

In a companion paper [4], space-time layered architectures (BLAST) and turbo coding/processing techniques, which are effective for single-link transmission, are combined with multiuser detection (MUD) methods for combating intercell interference. It is shown that, depending on the channel configuration, linear MMSE or successive interference cancellation (SIC) can be the preferable MUD method. Based on this fact, an adaptive scheme is developed. In this paper, the downlink capacity of interferencelimited multiple-input multiple-output (MIMO) cellular systems is investigated. It is found that the obtained MUD capacity is excellent in high to medium SIR scenario, but still deteriorates in strong interference environments, leaving ample room for possible improvement through other techniques. The performance of the proposed adaptive MUD scheme in a standard cellular environment, both in the nonline-of-sight (NLOS) and the line-of-sight (LOS) case, is simulated, and the advantages over the standard V-BLAST scheme are quantified.