Joint exploitation of spatial and multi-user diversity via space-time block-coding and antenna selection

The paper shows how both spatial and multi-user (MU) diversity can be jointly exploited in a cellular system. By combining space-time block-coding with transmit antenna selection (AS), system performance in terms of channel capacity and for a low to moderate number of users can be substantially improved with respect to the single-input single-output (SISO) case. However, a SISO configuration with AS outperforms both configurations for the whole range of active users. In terms of throughput, however, part or all of the advantage exhibited by the SISO and SISO-AS configurations is lost in favor of those featuring STBC schemes. Closed-form expressions are derived analytically for the SNR densities along with an approximate lower bound for system throughput.