User-specific link adaptation scheme for device-to-device network coding multicast

User-specific network controlled device-to-device (D2D) communication is a promising method to improve the system performance of the future cellular networks. It is a challenging task to realise the optimal link adaptation for D2D reliable multicast because of the nature of wireless radio channels. In this study, network coding is employed to enhance D2D multicast by introducing the characteristic that different information network-coded into a single multicast packet is destined to different receivers. A user-specific bit mapping algorithm is then proposed to make different information having a different equivalent coding rate before network-coded. A corresponding user-specific link adaptation scheme is proposed to adaptively choose an optimal modulation and coding scheme (MCS) for D2D multicast. Furthermore, the receiver detection procedure is then derived to recover the expected information for different users. As a result, different users obtain their respective information from a single network-coded multicast packet with different equivalent MCS according to the respective channel quality from the transmitter to them. Numerical results show that the user-specific link adaptation scheme can improve the capacity performance of network controlled D2D multicast. The throughput gain varies from 13 to 45% in different channel quality scenarios.