The D-OMA Method for Massive Multiple Access in 6G: Performance, Security, and Challenges

In this article, we introduce a new multiple-access method, delta-orthogonal multiple access (D-OMA), for massive access in future 6G cellular networks. D-OMA is based on the concept of distributed large coordinated multipoint (CoMP) transmission-enabled nonorthogonal multiple access (NOMA) using partially overlapping subbands for NOMA clusters. We demonstrate the performance of this scheme in terms of outage capacity for different degrees of NOMA subband overlapping. In addition, we propose a novel D-OMA-based physical-layer security scheme to enhance security provisioning in both uplink and downlink wireless access networks. Finally, we discuss practical implementation issues and open challenges for optimizing D-OMA.