Novel incremental relaying protocol based on spatial modulation

This paper presents a novel incremental relaying protocol based on spatial modulation for cooperative transmission over quasi-static rayleigh fading channel, namely spatial modulation incremental relaying (SMIR), which applies the concept of spatial modulation into incremental relaying. In the proposed protocol, information bits are mapped into two information carrying units: 1) a constellation point in the constellation diagram and 2) the spatial domain, i.e. into the location of a particular cooperative user number. The analytical expression of the frame error rate (FER) for SMIR protocol is derived. Simulation results confirm the presented mathematical analysis and show that SMIR protocol gains 2 and 3 dB in signal to noise ratio (SNR) over the conventional protocol for 3- and 5-bit/symbol transmissions respectively. Moreover, under this protocol the system can achieve a much higher throughput, which means that our proposed protocol brings significant gain in performance.