Beamforming and interference cancellation for D2D communication assisted by two-way decode-and-forward relay node

This paper investigates the device-to-device (D2D) communication underlaying cellular network assisted by a two-way decode-and-forward relay node. We assume the base station (BS) is equipped with M — antenna and serves its own cellular user while the D2D users communicate via a two-way decode-and-forward relay node. Both beam-forming (BF) and interference cancellation (IC) strategies at the BS are considered to improve the performance for the cellular link and D2D link, respectively. We first analyze the received signal-to-interference-plus-noise for the cellular link under BF and IC strategies and then derive the exact closed-form expressions for the cellular link. Asymmetric and symmetric cases are discussed for various locations of each user. Finally, the approximations for high signal-to-noise regime are also presented. Numerical results demonstrate the accuracy of the analytical and asymptotic results.