Space-time active rotation (STAR): a new layered space-time architecture

We propose space-time active rotation (STAR), a new layered space-time architecture for fading multiple-input multiple-output channels. The vertically layered V-STAR architecture is similar in spirit to the popular V-BLAST architecture, but by rotating the set of active antennas it achieves better performance with comparable complexity. We derive the outage probability and bounds on the diversity order of a V-STAR system. We propose an ordering algorithm that minimizes the outage probability of a successive cancellation decoder for the V-STAR system. Over a 4-input 4-output Rayleigh-fading channel, we show that V-STAR outperforms V-BLAST by 17.7 dB, and that V-STAR outperforms transmitter-optimized V-BLAST by 2.7 dB. The outage probability of V-STAR with successive cancellation decoding is only 1.4 dB away from the optimum outage probability achieved by an unconstrained decoder. This gap drops to 0.6 dB for an 8-input 8-output channel