Performance Improvement of NOMA Under Imperfect CSI and Inter‐Network Interference for Future Cellular Networks

ABSTRACT Future communications networks, including sixth‐generation (6G) and the internet of things (IoT), are expected to support higher capacity, quality of service, and user demands. However, serving a massive number of users in future networks poses the bandwidth limitation challenge. Non‐orthogonal multiple access (NOMA) has been proposed for the future IoT and 6G networks to address the mentioned problem by serving multiple users in one resource block. However, the practical approach for a multi‐cell network is to consider inter‐network interference and imperfect channel state information (CSI), which significantly deteriorates NOMA performance. This paper analyzes NOMA performance in terms of network outage probability, base station (BS) activity detection, and network sum rate under imperfect CSI and the presence of interference. In this regard, it proposes a method to improve the BS activity detection and network sum rate of NOMA networks, which exploits a lower computation complexity compared to similar research in the literature. The analytical and simulation results demonstrate the superiority of the proposed method over conventional NOMA and orthogonal multiple access (OMA) schemes in terms of network sum rate and base station detection activity.