  Cognitive radio non-orthogonal multiple access (CR-NOMA) networks promise
improved spectrum utilization and capacity in 5G networks. In this work, we aim
to investigate efficient power allocation for the secondary users (SUs) in
underlay CR-NOMA networks using a game-theoretic approach. We present a novel
power allocation to CR-NOMA network from a game-theoretic perspective. First,
we specify the utility function of the primary users (PUs) and SUs, and
formulate the game as a non-cooperative game. Then, the existence and
uniqueness of the Nash equilibrium (NE) are investigated. Finally, the sum
utilities of SUs is maximized by optimal power allocation at the NE point.
Simulation results provided that the proposed scheme outperforms the
conventional method, providing up to 37.5\% increase in sum utilities of the
SUs.
