An Uplink Node Pairing Algorithm for Non- orthogonal Multiple Access Backscatter Communication Systems

To further improve energy supplement and spectrum efficiency in non-orthogonal multiple access (NOMA) assisted backscattering communication, in this paper, a novel node pairing algorithm, dual-node pairing (DNP-BG) algorithm, is proposed. Specifically, based on the distance between the backscatter nodes (BNs) and the reader, the coverage area is divided into two sub-areas. To achieve double-node pairing, we analyze this scenery with the weighted bipartite graph and try to find the maximum weight matching of it. Subsequently, we take maximum weight sum of the weighted bipartite graph to achieve the backscatter node pairing. Simulation shows that the number of successfully decoded bits with our proposed scheme outperforms that of other pairing algorithms, in both the thresholds of signal to interference noise ratio (SINR) and transmit power.