Resource allocation in power domain NOMA‐based cooperative multicell networks

In this paper, we propose a novel resource allocation scheme for non-orthogonal multiple access (NOMA) based cooperative cellular networks where in each cell, two pairs of transmitter-receiver want to communicate via the base station (BS) which serves as a decode-and-forward (DF) relay. In the first hop, the transmitters simultaneously transmit their information and the BS applies joint decoding method. The BS transmits the received information towards the receivers based on NOMA technique. The receivers apply the successive interference cancellation (SIC) where the SIC ordering of receivers is determined based on the direct channel gain. We formulate the resource allocation problem as an optimization problem which is non-convex. To tackle the non-convexity, we adopt the successive convex approximation (SCA) with difference of two concave functions (D.C.) as the approximation technique. We also study the computational complexity of our proposed scheme. Finally, we study the performance of our scheme by simulations and compare it with existing transmission schemes like the orthogonal frequency multiple access (OFDMA) and the case where both of the first hop and the second hop adopt PD-NOMA as well as the case where a special sort of subcarrier pairing is performed between the first and second hops.