Space-time block coded spatial modulation with labeling diversity

Space-time block coded spatial modulation (STBC-SM) exploits the advantages of both spatial modulation and the Alamouti space-time block code. Meanwhile, space-time labeling diversity has demonstrated an improved bit error rate (BER) performance in comparison to the latter. Hence, in this paper, we extend the application of labeling diversity to STBC-SM, which is termed STBC-SM-LD. Under identical channel assumptions, STBC-SM-LD exhibits superior BER performance compared to STBC-SM. For example, with , 64-quadrature amplitude modulation (64-QAM), STBC-SM-LD has a BER performance gain of approximately 2.6dB over STBC-SM. Moreover, an asymptotic bound is presented to quantify the average BER performance of M-ary QAM STBC-SM-LD over independent and identically distributed Rayleigh frequency-flat fading channels. Monte Carlo simulations for STBC-SM-LD agree well with the analytical framework. In addition to the above, low-complexity (LC) near-maximum-likelihood detectors for space-time labeling diversity and STBC-SM-LD are presented. Complexity analysis of the proposed LC detectors shows a substantial reduction in computational complexity compared to their ML detector counterparts. For example, the proposed detector for STBC-SM-LD achieves a 91.9% drop in computational complexity for a, 64-QAM system. The simulations further validate the near-maximum-likelihood performance of the LC detectors.