Spatial Modulation and Sparse Regression Codes

The use of multiple antennas at both transmitter and receiver significantly improves the performance of wireless communication systems. multiple-input multiple-output (MIMO) systems are typically paired with orthogonal frequency-division multiplexing (OFDM) to handle frequency selective (FS) channels in an efficient way. This paper focuses on single-carrier MIMO systems using spatial modulation (SM), which transmits information by selecting a few active antennas from a larger set. Using segmentation at the transmitter, SM systems have the same mathematical structure as spatially coupled sparse regression codes (SC-SPARCs) and additive white Gaussian noise (AWGN) transmission. These codes are known to achieve AWGN capacity with approximate message passing (AMP) decoding. We analyze the performance of SM with AMP decoding for FS channels. This approach handles intersymbol interference without the need for cyclic prefixes. We compare different AMP variants and examine the impact of various system parameters like the channel memory and modulations schemes.