Cooperative non-orthogonal multiple access using two-way relay

The existing work on cooperative non-orthogonal multiple access (NOMA) considers one-way relaying which consumes extra channel resources for the relaying operation. The use of extra channel resource results in degradation in spectral efficiency. This paper proposes two-way relaying in cooperative NOMA to enhance the spectral efficiency. The proposed scheme enable two-way information exchange between base station and users without consuming extra channel resource. In additional, the NOMA power allocation region is proposed to achieve a better rate compared to orthogonal multiple access scheme. Based on Monte Carlo simulation, the proposed scheme is shown to achieve better sum rate compared to OMA scheme and conventional cooperative NOMA.