Joint Power Control and Beamforming Design for RIS-Assisted D2D Networks with Energy Constrained Nodes

This paper investigates sum-rate maximization for reconfigurable intelligent surface (RIS)-assisted device-to-device (D2D) networks, while ensuring that the energy constraints of the wireless nodes are satisfied. The formulated problem involves the joint optimization of the phase-shifts of the RIS reflecting elements (passive beamforming) and the transmit power control for each transmitter. Given the highly non-convex nature of this optimization problem, obtaining its global optimal solution is non-trivial. To this end, we propose a new algorithm that leverages fractional programming and penalty dual decomposition techniques to obtain a high-quality sub-optimal solution. Our numerical results highlight the superiority of the proposed algorithm, as it consistently achieves substantially higher sumrates in comparison to the benchmark schemes.