Power allocation and user clustering for uplink MC-NOMA in D2D underlaid cellular networks

In this letter, the resource allocation problem for uplink multi-carrier non-orthogonal multiple access (NOMA) in device-to-device (D2D) underlaid cellular networks is investigated. Due to the existence of D2D pairs, NOMA users are subject to varying degrees of interference. We formulate the problem as a Nash bargaining game to maximize the Nash product of each user. We propose an iterative algorithm applying Karush-Kuhn-Tucker conditions to solve the power allocation problem and modeling the user clustering as a Hedonic coalition game. Simulation results verify the convergence of the proposed algorithms. Besides, the algorithms achieve near-optimal performance compared to exhaustive search method and the throughput and fairness in NOMA are both higher than those in orthogonal multiple access.