Multi-source network-coded D2D cooperative content distribution systems

In this paper, we investigate the information transmission in a typical 5G device-to-device (D2D) communication application scenario, i.e., a content distribution system with a number of information sources intending to broadcast their messages to multiple destinations in the vicinity. Due to the dynamic nature of wireless signal propagation links, it is hard to guarantee a satisfactory performance by direct source-destination transmissions, especially when the system is operating in a reuse-mode. Relays can be introduced to the system to solve this problem. However, adopting the conventional repetition coding at relays inefficiently utilizes the available resources, for the considered multi-source scenario. Therefore, we investigate applying a class of finite-field network codes at the relays, when potentially three types of relays are deployed to assist the information distribution process. We proposed the algorithms to derive the system outage probability and analyze the trade-off between energy efficiency and spectral efficiency. Our analytical and numerical results clearly demonstrate the potential of exploiting network-coded cooperative communications in future 5G D2D systems.