Power Allocation for NOMA Based Layered Multicast Transmission

Non-orthogonal multiple access (NOMA), as a promising technology in 5G, can effectively improve the spectrum efficiency and user speed. The performance of multicast services in mobile communication networks is limited by the rate of the worst user, while NOMA can improve the quality of services for optimal channel users while guaranteeing the rate of the worst user of multicast group through power domain reuse. We focus on power allocation algorithms for NOMA based layered multicast transmission in this paper, with the purpose of maximizing sum rate in multicast system while giving attention to user fairness under the constraint of minimum rate and total transmit power. Based on layered multicast scene, a corresponding joint optimization algorithm for user group formation and power allocation is proposed. The effects of noise, user channel gain and power ratio on system performance were analyzed by means of theoretical analysis and simulation. Simulation results show that this algorithm further improves the sum rate of the system.