ACGMA: Adaptive Channel Gain Multiple Access Scheme for Data Rate Improvement in Ultra-Dense Networks.

Rate splitting multiple access (RSMA) is a flexible multiple access (MA) scheme in downlink scenarios for wireless networks. With the inclusion of many applications, conventional Multiple Access (MA) schemes such as Orthogonal Multiple Access (OMA) and Non-Orthogonal Multiple Access (NOMA) become difficult to implement for current network conditions. Additionally, the overall performance of networks is restricted due to fluctuations in interference levels for different scenarios. Therefore, in this work, we propose an Adaptive channel gain MA scheme (ACGMA) that selects the best MA scheme for a given combination of user pairs available in a small cell. A pairing scheme is designed to find optimal pairs of users along with their best-opted MA scheme (OMA, NOMA, or RSMA). Moreover, power allocations are derived for different sub-messages based on their preferences for target rates. The proposed scheme performs well for different interference levels and can switch to a better MA scheme by adjusting power. Through our in-depth experimental results, it is shown that the proposed ACGMA scheme achieves a 20% increase in sum rate in comparison to a RSMA-only system. Furthermore, the increase in sum rate for the proposed ACGMA scheme is around 30% for NOMA-only systems.