On the Optimality of SPRAS-MIMO for Spatial Multiplexing Transmission

Significant capacity improvements are possible when the multiple antennas are employed at both the transmitter and receiver. However, the application of multiple antenna systems is restricted by increasing of the cost and complexity of radio frequency (RF) subsystem. The authors in J. Ahmadi-Shokouh et al. (2006) presented a novel structure which not only overcomes the aforementioned limitation but also enhances the capacity of multi-input and multi-output (MIMO) systems by using smart passive receive antenna selection (SPRAS) concept. In this paper, we find an upper-bound for the optimal solution of the SPRAS weighting matrix in the spatial-multiplexing transmission. The performance of the proposed system is evaluated via analysis and simulation and compared with other antenna selection strategies. It is shown that the proposed SPRAS-MIMO system not only outperforms the similar antenna selection schemes with the same number of RF chains but also performs better than the full-complexity MIMO system