Base station energy consumption for transmission optimised spatial modulation (TOSM) in correlated channels

Radio frequency (RF) chains are responsible for a large percentage of the total BS energy consumption and each RF chain can only support one activated transmit antenna at a time. This fact greatly benefits spatial modulation (SM) since at any given time instance only one antenna in an array is active. The proposed transmission optimised spatial modulation (TOSM) is an adaptive SM scheme which trades off the spatial constellation size with the signal constellation size to minimise the average bit error probability (ABEP) for a given channel correlation. It outperforms fixed-SMscheme for different channel correlation degrees. In this paper, we construct a single RF chain BS based on TOSM which has low complexity and high energy-efficiency. Simulation results show that for a given spectral efficiency of 6 bits/s/Hz and two receive antennas, the proposed scheme outperforms 2×2 V-BLAST by at least 3.8 dB in energy consumption.