Virtual full-duplex distributed spatial modulation with SER-optimal and suboptimal detection

Spatial modulation, a multiple-input multipleoutput (MIMO) technology which uses the antenna index as an additional means of conveying information, is an emerging technology for modern wireless communications. In this paper, a new distributed version of spatial modulation is proposed which achieves virtual full-duplex communication (VFD-DSM), allowing the source to transmit new data while the relay set forwards the source's data in every time slot. Two maximum a posteriori (MAP) detection methods at the destination are proposed for this VFD-DSM protocol: one, called local MAP, is based on processing the signals received over each pair of consecutive time slots, while the other, called global MAP, is based on symbol-error-rate optimal detection over an entire frame of data. Simulation results for the proposed VFD-DSM protocol indicate that for source data detection at high signal-to-noise ratio (SNR), VFD-DSM with local MAP detection can provide a similar error rate performance to that of successive relaying, while providing a significant throughput advantage since the relays can forward the source transmissions while also transmitting their own data. Furthermore, the use of global MAP detection is shown to yield a further 1.8 dB improvement in source data error rate while still maintaining this throughput advantage.