Cooperative Non-Orthogonal Multiple Access Scheme for Cellular Two-Way Relay Networks

We design a spectral-efficient two-way cooperative transmission scheme for a two-user cellular system, which consists of a base station (BS), a near user and a far user. The proposed scheme is based on cooperative non-orthogonal multiple access (CNOMA) and physical-layer network coding (PLNC), which is able to support the two-way data transmission within three time slots. We derive the ergodic sum-rate upper bound of the proposed two-way cooperative NOMA scheme with a closed-form expression. Numerical results show that the derived upper bound is tight and the proposed scheme can improve the sum-rates significantly as compared with existing schemes.