Multiuser Detection for FEC-Coded Massive Spatial Modulation MIMO: An Iterative Interference Rejection Approach

In this paper, we investigate the issue of multiuser detection (MUD) in a massive spatial modulation (SM) multiple-input multiple-output (MIMO) system, where the base station is equipped with a large number of antennas and each user equipment uses single-carrier SM (SC-SM) for uplink transmission. Unlike the conventional MUD for massive SM-MIMO systems, the application of forward error correction (FEC) coding is explored in our design, which is utilized to combat the impact of multiuser interference (MUI). More specifically, we propose to utilize the soft information from the FEC decoder to iteratively improve the MUI rejection procedure and provide more accurate estimation of the transmitted signals. The soft information is exchanged between the decoder and the MUI cancellation unit, which constitutes a turbo structure and leads to simultaneous improvement of the mean square error and the bit error ratio performance. The performance gain is substantiated by theoretical analysis as well as numerical simulations.