Graph-Theoretical Dynamic User Pairing for Downlink NOMA Systems

We propose a novel graph-theoretical dynamic user pairing strategy based on the rate requirements in cellular networks employing non-orthogonal multiple access (NOMA). The proposed approach relies first constructing conflict graph corresponding to all possible pairings and then reformulating problem of finding best pairs as that maximum weighted independent set (MWIS) graph. This formulation turns originally NP-hard into one can be solvable polynomial time thanks claw-freeness property method satisfies number demands with optimal network sum-rate shown theoretically validated by simulation results.