Reconfigurable Intelligent Surfaces Enhanced NOMA D2D Communications
Underlaying UAV Networks
Abstract
This paper considers RIS enhanced D2D communications underlaying
unmanned aerial vehicle (UAV) networks with non-orthogonal multiple
access (NOMA). The objective is to maximize the sum rate of NOMA D2D
communications by optimizing the power budget of D2D transmitter, NOMA
power allocation coefficients of D2D receivers and passive beamforming
of RIS while guaranteeing the quality of services of UAV user. Due to
non-convexity, the optimization problem is intractable and challenging
to handle. Therefore, it is solved in two parts using alternating
optimization. Simulation results unviel the performance of the proposed
RIS enhanced D2D communications scheme. Results demonstrate that the
proposed scheme achieves 15\% and 27\%
higher sum rates compared to the fixed power D2D and orthogonal D2D
schemes.