Performance Analysis of Relayed D2D Communications under Power Control

In this paper, we consider a relay-aided device-to-device (RA-D2D) communication link operating within a cellular network. The underlay mode where the D2D users share the uplink frequency resources of the cellular link is considered. An optimal algorithm for allocating the appropriate D2D transmit powers that maximize the ergodic capacity of the D2D link while ensuring the cellular communication requirements is proposed. The performance of the proposed scheme is then analyzed in terms of the ergodic capacity of the RA-D2D link. The improvement in the spectral efficiency is compared with the half-duplex (HD) and the full-duplex (FD) modes of D2D communications. Results show that the relay-aided system outperforms the HD system and even the FD system above a certain threshold of self-interference.