Spectral Efficient Generalized Spatial Modulation Aided MmWave Massive MIMO

In this paper, a novel generalized spatial modulation (GenSM)-aided millimeter-wave (mmWave) massive multiple-input multiple-output (MIMO) system is proposed for indoor transmission over line-of-sight (LoS) channels. Unlike the conventional GenSM-based mmWave systems, the application of digital beamforming (DBF) and the impact of spatial-domain codebooks are explored in our work. More specifically, we first propose a closed-form lower bound for quantifying the achievable spectral efficiency (SE) of our system. Then we seek to optimize the spatial-domain codebook and DBF design with respect to SE maximization. Lastly, numerical simulations are provided to substantiate the performance gain achieved by the proposed system compared against the conventional spatial multiplexing (SMX) MIMO schemes with waterfilling precoding.