SRSM-Based Adaptive Relay Selection for D2D Communications

This paper proposes an adaptive relay selection method that exploits the social network and establishes a physical domain and social domain-based model named the Social-based device-to-device (D2D) relay selection model to address relay selection failure caused by the diversity of users cooperation willingness and the instability of communication links due to human mobility. Under the premise of tolerable interference caused to cellular users, the proposed approach synthetically considers the desired physical-relation factor and the social-interaction factor for the relay user. In particular, the reliability of the D2D link is obtained by considering the transmission stability of the link, assessed by the user encounter history and cooperation willingness characterized by user social distance, which is set as the criterion of relay selection, combined with the physical channel condition. Simulation results show that compared with the traditional socially blind method, the proposed method can increase the probability of relay selection success and reduce the burden of the cellular network to improve the system performance.