Multi-User Differential Spatial Modulation scheme for massive MIMO uplink communications

Abstract

Spatial Modulation (SM) is a Multi-Input Multi-Output (MIMO) transmission technique where only one antenna transmits data in each transmission interval, leading to a reduction in the number of RF chains and transmission power. The application of SM in Massive MIMO systems relies on perfect channel estimation, which is a fundamental challenge in these systems. Differential Spatial Modulation (DSM) is a method proposed to avoid channel estimation challenges. However, the conventional square DSM cannot easily be applied to multi-user communication applications. In this paper, a novel Multi-User Differential Spatial Modulation (MU-DSM) transmission scheme is proposed for multi-user massive MIMO uplink communications. Moreover, for the proposed transmission scheme, a non-coherent MU-DSM detector is presented. As demonstrated in the analytical and simulation results, the proposed MU-DSM scheme performs very close to its coherent counterpart where perfect channel information is available.