MMSE Precoding for Receive Spatial Modulation in Large MIMO Systems

Receive spatial modulation (RSM) schemes enable simple and energy efficient multiple-input-multiple-output (MIMO) transceivers and yet attain high spectral efficiency, which renders them promising schemes for millimeter wave (mmWave) communication in massive MIMO systems. When these schemes are designed to include zero forcing (ZF) precoders, performance can be impaired in the presence of highly spatially correlated channels. Extending these schemes for minimum mean square error (MMSE) precoding is not trivial due to the hardware constraints of the energy efficient user terminal architecture. In this paper, we adapt the MMSE precoder to the low complexity RSM architecture and develop detection methods for the spatial and modulation symbols. The proposed MMSE RSM scheme with total and per-antenna power constraints have been compared with ZF RSM in terms of average and outage mutual information by simulations showing superior gain for mmWave channels.