Resource Allocation for Non-Orthogonal Multiple Access with Coordinated Multipoint Support

Current mobile networks are based on orthogonal multiple access (OMA), in which at most one user is served in a resource block (RB). Unlike OMA, non-orthogonal multiple access (NOMA) enables an RB to be accessed by multiple users concurrently, thus improving RB usage efficiency. In this paper, we study resource allocation for NOMA when coordinated multipoint (CoMP) transmission is supported and users have minimum rate requirements. Given a NOMA/user pair, we derive closed-form formulas for optimal power allocation that maximizes utility, which is a weighted sum of rates of the two users. We also develop an efficient method for user pairing, in order to maximize the number of users whose rate requirements are met. Simulation results show that our method results into better performance in terms of the number of well-served users and total utility.