Cooperative Game Aided Spectrum Sharing in Underlay Cognitive Radio Networks Employing NOMA Schemes

In this paper, we investigate the spectrum sharing in an underlay cognitive radio network conceived, in which non-orthogonal multiple access (NOMA) scheme is applied. One of the famous cooperative games, namely non-transferable utility (NTU) coalition formation game, is leveraged for the implementation of spectrum sharing between the cognitive users (CUs) and the primary user (PU) in the underlay CR network. In particular, the pragmatic coalition formation algorithm is proposed to find the stable coalitions of CUs. Then, upon choosing the best CU coalition for accessing the PU's spectrum, we carry out the appropriate power allocation for the CUs. The simulation results show that, the proposed algorithm can achieve an enhance spectrum efficiency for the underlay CR network. Furthermore, the results reveal the superior performance of the NOMA scheme over traditional orthogonal multiple access (OMA) scheme in the context of our underlay CR network.