Hybrid Multiple Access Using Simultaneously NOMA and OMA

Abstract

This paper proposes a hybrid multiple access scheme using both non-orthogonal multiple access (NOMA) and orthogonal multiple access (OMA) to overcome the inherent problems of NOMA. In NOMA, as multiple access is performed within the power domain, a small difference in the channel gain between users or an increase in the number of simultaneous users reduces the effectiveness. To cope with these problems, the proposed scheme applies a novel combination of NOMA and OMA as well as NOMA for multiple access patterns, and then determines the best pattern based on the system capacity. The effectiveness of the proposed scheme is demonstrated in comparison with conventional hybrid multiple access using NOMA and OMA through computer simulations.