Adaptive Low-Complexity Multiple Access Scheme for Green Downlink Multi-User Multi-Antenna Systems

Multiple access schemes are essential for achieving high performance in cellular networks. Additionally, they significantly impact the power consumption of the Radio Access Network (RAN), which is the primary power-consuming component of the cellular network. Rate Splitting Multiple Access (RSMA) is currently regarded as a promising and attractive multiple access scheme. In this work, we introduce Selection Multiple Access (SMA) and compare it to RSMA. In SMA, the multiple access scheme is dynamically selected based on channel state information. We evaluated SMA and RSMA in terms of capacity, power consumption, energy efficiency, and processing time (used as a metric for complexity). RSMA demonstrated better capacity performance, offering up to 28% increase over SMA. However, it also consumes up to 24% more power compared to SMA. Furthermore, SMA achieves significantly better energy efficiency, with up to 47.59% improvement over RSMA, and offers much lower processing time, particularly when the users’ channels are sufficiently orthogonal.