Reconfigurable Intelligent Surface Empowered Device-to-Device Communication Underlaying Cellular Networks

Reconfigurable intelligent surface (RIS) is a new and revolutionary technology to achieve spectrum-, energy- cost-efficient wireless networks. This paper studies the resource allocation for RIS-empowered device-to-device (D2D) communication underlaying cellular network, in which an RIS employed enhance desired signals suppress interference between paired D2D links. We maximize overall network’s spectrum efficiency (SE) energy (EE), respectively, by jointly optimizing reuse indicators, transmit power, RIS’s passive beamforming BS’s receive beamforming. To solve both mixed-integer non-linear programming problems, we first propose efficient low-complexity user-pairing scheme based on relative channel strength determine indicators. Other variables are then optimized SE iterative algorithm, techniques of alternating optimization, successive convex approximation, Lagrangian dual transform quadratic transform. The EE-maximization problem solved algorithm integrated with Dinkelbach’s method. Numerical results show that proposed design achieves significant EE enhancements compared traditional underlay network without RIS, relay-assisted other benchmarks.