Performance analysis of the maximum ratio transmission preprocessing for extended receive antenna shift keying

The Extended Receive Antenna Shift Keying (ERASK) scheme is a MIMO scheme based on the Receive Spatial Modulation concept, invented to increase the overall spectral efficiency, by exploiting all possible combinations of receive antenna indexes. In this paper, we evaluated the ERASK scheme using the Maximum Ratio Transmission (MRT) preprocessing (MRT-ERASK), using the real amplitude threshold detector and compare it with the ERASK scheme using the Zero Forcing (ZF) preprocessing (ZF-ERASK). Analytical derivations of the received signal of the MRT-ERASK show that a complex inter-antenna interference is added to other antennas depending on the transmitted spatial symbol. The Bit Error Rate performance is also derived analytically. Simulation results over MIMO Rayleigh channel are provided to compare both systems, showing that ZF-ERASK outperforms MRT-ERASK but at the expense of a higher implementation complexity for ZF-ERASK. On the other hand, increasing the number of transmit antennas of a MRT-ERASK improves its performance getting closer to the performance ZF-ERASK. Therefore, the higher the number of transmit antennas, the nearer the performance of both systems, and the more suitable the MRT-ERASK to be implemented.