Multi-Set Space-Time Shift-Keying With Reduced Detection Complexity

In this paper, we propose a novel multi-set space-time shift keying (MS-STSK) technique, where the source bits are conveyed over two components, namely, by activating one out of M
_Q
dispersion matrices of STSK and M antenna combination of the N
_t
available antennas, in a similar fashion to spatial modulation but activating multiple antennas rather than a single antenna. This system requires a smaller number of RF chains than antenna elements (AEs) to achieve an improved throughput. We opt for STSK as the main building block of our proposed MS-STSK as a benefit of its design flexibility, where STSK is capable of providing the system with both diversity and multiplexing gains. The proposed MS-STSK system achieves both higher data rates and a lower bit error rate than the conventional STSK scheme, which is attained at the cost of increased number of AEs and a high-speed antenna switch. Furthermore, as the symbol rate of the MS-STSK system increases, its performance compared with the STSK scheme is significantly improved because of the enhanced diversity introduced by the additional AEs. Furthermore, we propose a reduced complexity detector for Quadrature Amplitude Modulation (QAM)/Phase Shift Keying (PSK) constellations, which-despite its reduced complexity-is capable of achieving the same performance as the optimal maximum likelihood detector.