LAUSR

Abstract The device-to-device (D2D) communications effectively reduce the load of base station and solves the problem of communication resource shortage. Thanks to the relay-assisted communication technology, D2D can expand the coverage and improve the reliability. But there may not be sufficient relay users to match each D2D user. On the other hand, in order to save the user resources, reduce energy consumption, and expand the access number of the cell users, this paper constructs a system model for multiple pairs of D2D users to communicate through one relay, and describes the session process and data transmission process while network coding (NC) is introduced to promote the performance. For the purpose of further improving system performance, this paper proposes a relay selection method that combines the relay location, communication content, residual energy and system capacity. The proposed method not only has a low complexity (easy for implementing), but also can greatly increase the achievable system capacity after network coding assisting communication and relay selection, which is proved through numerical results.