Spatial Modulation in Multifunctional MIMO Techniques for 5G and Beyond

Abstract

Multiple-input multiple-output (MIMO) communications initiate promising techniques for the pragmatic design of 5G wireless communication networks by offering spatial multiplexing, diversity, and beamforming gains. Large-scale or massive MIMO (mMIMO) evolves as an inherent benefit of operating at higher frequency bands, like millimeter-wave (mmWave). However, the depiction of traditional MIMO architecture in mMIMO systems requires a dedicated radio frequency (RF) chain for each antenna element, which results in an immense amount of hardware complexity and power consumption. In this context, spatial modulation (SM) serves as a potential transmission technique, where the indices of the transmit (TSM) and receive (RSM) antennas convey information in addition to the conventional transmit signal constellation symbols. SM aids in circumventing the requirement of dedicated RF chains for each transmit antenna and increases the transmission rate. Nonetheless, TSM at mMIMO systems deteriorates the beamforming gain. Therefore, multifunctional MIMO transmission arrangements attract wide recognition, and as the terminology implies, it combines the multitude of benefits in MIMO systems. newline