On MRC-Based Detection of Spatial Modulation

In this paper, the performance of suboptimal detection of spatial modulation (SM) based on the so-called maximum ratio combining (MRC) is investigated. In this detection scheme, in contrast to maximum likelihood (ML) detection, transmit antenna index and amplitude-phase modulation(APM) symbols are detected separately in two stages. Therefore, the detection complexity of SM can be significantly reduced. We analyze the instantaneous and average symbol error rate (SER) of such a detection scheme and compare it with that of the optimal ML detection. Also, we propose an adaptive space modulation scheme to minimize the SER of MRC detection by utilizing the channel state information. Finally, the problem of constellation breakdown of SM in the presence of the MRC detection for the special case of the phase-shift keying (PSK)-modulated SM is investigated. The derived analytical results are further validated using extensive simulations.