An adaptive relay selection strategy for user cooperation networks based on social-aware

As independent individuals with social attributes, the users for collaborative transmission may have private behaviors such as refusing to relay. By leveraging both near user (NU) and alternative dedicated relay node, an adaptive relay selection strategy based on social-aware is proposed for downlink non-orthogonal multiple access (NOMA) networks. In this framework, a social relationship model is established based on the interest similarity and contact duration between NU and far user (FU). On this basis, the closed form and asymptotic expressions for the outage probability are derived. And the K+1 order diversity gain of the proposed strategy is proved. Simulation results show that the proposed strategy can improve the reliability of communication links and transmission performance.