Energy-Efficient and Low-Complexity Uplink Transceiver for Massive Spatial Modulation MIMO

In this paper, we design the uplink transceiver for a new multiuser (MU) massive spatial modulation (SM) multiple-input-multiple-output (SM-MIMO) system over frequency-selective fading channels, where the base station (BS) is equipped with massive antennas, and user equipment (UE) has multiple transmit antennas (TAs) but only one radio-frequency (RF) chain. UE transmit data bits to the BS simultaneously by cyclic-prefix single-carrier (CP-SC) SM. For the uplink MU detection (MUD), we construct a low-complexity generalized approximate message passing detector (GAMPD), which can exploit both the sparsity and prior probability distribution of the transmitted signal and is suitable for hardware implementation because its most complex operation is only matrix-vector multiplication. Its mean square error (MSE) and uncoded bit error rate (BER) performances are also analyzed based on the state evolution (SE). Compared with stagewised linear detectors, GAMPD shows orders-of-magnitude lower complexity. Moreover, simulation results indicated that GAMPD approaches to the performance of maximum-likelihood (ML) detection and outperforms minimum MSE (MMSE) significantly. Finally, to design energy-efficient massive SM-MIMO, we propose a practical algorithm to optimize the key system parameters (e.g., the transmission power, the numbers of the BS antennas or UE, or the TAs at the UE). Numerical results indicate that low BS circuit power consumption and long channel coherence time are the two key prerequisites for the success of massive SM-MIMO.