Energy Efficient Relay Selection in Multi-hop D2D Networks

This paper studies energy-efficient relay selection schemes for cooperative multi-hop device-to-device (D2D) networks. D2D networks exploit proximity gain by establishing direct links between devices instead of relying on cellular links for communication. We consider a D2D network with random deployment of relay nodes between the source and the destination. The relay nodes are grouped into clusters, which act cooperatively to enhance network reliability. We derive received power and end-to-end transmission success probability expressions for a single-hop, two-hop and multi-hop network scenario assuming a Rayleigh fading channel and path loss. Further, we compare two relay selection schemes: i) random relay selection (RRS) and ii) Signal-to-noise ratio (SNR)-based relay selection (SRS) on the basis of energy-efficiency that provides a required quality of service (QoS).