Network coding in device-to-device (D2D) communications underlaying cellular networks

Multi-hop cooperative communications have been considered to increase the coverage range of device-to-device (D2D) communications underlaying cellular networks. Whilst network coding (NC) has been proven as an efficient technique to improve the throughput of ad-hoc networks, it has not been adapted to D2D networks. In this paper, we propose a NC-D2D system, in which we apply NC into the multi-hop D2D communications to enhance its throughput. We then develop a radio resource management (RRM) mechanism that jointly optimises the power control and subchannel allocation for NC-D2D communications. The proposed RRM maximises the throughput of NC-D2D communications while guaranteeing the quality of service (QoS) requirements of conventional cellular (CC) UEs. We also investigate how caching capabilities at relay nodes would impact the system performance. Simulation results show that by employing NC and our proposed RRM mechanism, the throughput of multi-hop D2D communications is significantly improved and the time required for exchanging large data files between a D2D pair is dramatically reduced as compared to existing multi-hop D2D schemes.