Impact of Imperfect Channel Estimation on the Performance of Spatial Modulation MIMO Systems

This paper aims to analyse the performance of spatial modulation (SM) techniques under imperfect channel state information (iCSI), i.e., errors in the estimation of channel coefficients. The results are compared with the classic spatial multiplexing technique V-BLAST. Furthermore, computational complexity for both SM and V-BLAST are evaluated in terms of complex-values operations under the same spectral efficiency. Simulation results show that SM is more robust to imperfect CSI than V-BLAST while maintaining lower computational complexity for binary modulation order and spectral efficiency S values of order of tens or smaller. This robustness is remarkable especially under a large number of transmit antennas condition, which is an important feature to be considered in the next Dense-MIMO system applications. In general, it is noted that the performance of both SM with ML detector and V-BLAST are degraded as the channel errors increase. However, spatial modulation is more robust while maintaining a reduced complexity for S ≤ 13 bps/Hz. For instance, under a BER of 10−4 and a channel percentage error of ε% = 10%, the increasing in SNR is about 1.2 dB for SM with Nt = 16, while for V-BLAST this SNR degradation is ≈ 3 dB.