Performance Tradeoff in Relay Aided D2D-Cellular Networks

Abstract

With the explosive growth of multitudinous wireless services and high-data-rate required applications, relay aided Device-to-Device (D2D) communications have attracted increasing attentions. In this correspondence, we investigate the performance tradeoff in relay aided D2D-cellular networks, where D2D users reuse the resource of cellular uplink transmissions. To optimize the performance of relay aided D2D communications, we first study the tradeoff between spectral efficiency (SE) and energy efficiency, and propose a source-relay joint power allocation scheme. The optimal transmit powers for both source and relay users are derived, based on which we further introduce a SE-variation function to explicitly evaluate the impact of enabling D2D communications on D2D-cellular networks. Theoretical analysis and simulation results demonstrate the viability of the proposed scheme and provide comprehensive insights into the coexistence of different systems.