Using full duplex relaying in device-to-device (D2D) based wireless multicast services: a two-user case

D2D communication has been proposed as an important supplement to the existing centralized cellular networks which allows two physically adjacent cellular user equipments (UEs) to communicate directly. This paper concerns using D2D to improve wireless multicast services in cellular networks. Specially, we consider a D2D transmitter UE can act as a full-duplex (FD) relay to assist a cellular multicast from a base station (BS) to a group of two UEs. And a new scheme which allows an intra-cell D2D retransmission to underlay a cellular multicast is proposed. Under the constraint of the minimum signal-to-interference-and-noise ratio (SINR) required by each of the receiver UEs, the aim of the scheme is to select the best UE in a multicast group to perform the D2D retransmission with the serving BS. Thus, the aggregate transmit power consumed at the BS and at the selected UE can be minimized. The numerical results show that the proposed scheme outperforms traditional cellular multicast scheme as it consumes less transmit power to achieve the same SINR target at the receiver UEs.