NOMA-Enabled Layered Video Multicast in Wireless-Powered Relay Systems

This letter proposes a novel layered video multicast scheme for wireless-powered relay systems, where the multi-antenna base station multicasts layered video signals over non-orthogonal multiple access (NOMA) to heterogeneous user groups with the help of a dedicated relay. To minimize the average transmission power of the base station, an optimization problem is formulated to jointly design the energy signal power and layered video multicast beamformers, while guaranteeing all the users' quality of experience (QoE), i.e., fluent video playback and successful decoding of video signals. Since the formulated optimization problem is non-convex, a low-complexity algorithm is developed to obtain a local minimum, and a novel initial feasible point search algorithm is proposed to initialize the solving process. Simulation results reveal that the proposed scheme works well and can greatly reduce the power consumption.