Abstract: In the D2D(Device-to-Device) communication system, when the distance between the source node and the destination node is too long, the communication delay is large and the communication process is interrupted. A relay selection algorithm for D2D communication based on social relationship and energy cache is proposed. Under the premise of limiting the location of the relay node, the algorithm considers the conventional conditions such as transmission rate, residual energy of the relay and residual buffer space, and considers the social relationship between nodes and the outage probability of the link. The weight of each link is calculated comprehensively, and the link with the highest weight is selected for data transmission. The simulation results show that the proposed algorithm effectively reduces the transmission delay of D2D communication link, improves the successful transmission probability of the system, and improves the stability of the relay system.

Key words: social relations, outage probability, relay selection, energy perception, device-to-device(D2D) communication