Reconfigurable Intelligent Surface Assisted Device-to-Device Communications

With the evolution of 5G, 6G and beyond, device-to-device (D2D) communications have been developed as an energy-, spectrum-efficient solution. However, D2D links are allowed to share same spectrum resources with cellular links, which will bring significant interference those links. Fortunately, emerging technique called reconfigurable intelligent surface (RIS), can mitigate aggravated caused by adjusting phase shifts create favorable beam steering. In this paper, we study RIS-assisted single cell uplink communication scenario, where a link multiple RIS is adopted mutual interference. The problem maximizing total system rate formulated jointly optimizing transmission powers all discrete surface. To obtain practical solutions, capitalize on alternating maximization decomposed into two sub-problems. For power allocation, difference concave functions (DC) problem, solved gradient descent method. shift optimization, local search algorithm utilized. Simulation results show that deploying optimized effectively eliminate in networks.