Energy Efficiency Optimization Algorithm of Cooperative Non-Orthogonal Multiple Access joint Simultaneous Wireless Information and Power Transfer Based on Successive Convex Approximation

In a traditional Non-Orthogonal Multiple Access (NOMA) system, more power is usually allocated to edge users to ensure its communication quality. However, the fairness of the system comes at the expense of system capacity. Introducing collaborative communication into the NOMA system, the central user also needs to assume the role of relay in the collaboration phase. This method will inevitably bring a certain burden to the central user. In order to balance system capacity and fairness, a new resource allocation scheme based on cooperative communication and Simultaneous Wireless Information and Power Transfer (SWIPT) is proposed. Energy harvesting equipment is used for energy harvesting, and maximizes the energy efficiency of the system by solving the target problem through Successive Convex Approximation (SCA). Compared with the traditional NOMA and Cooperative NOMA, the energy efficiency of the CNOMA-SWIPT system is greatly improved. When the maximum transmit power of the base station is 30 dBm, CNOMA-SWIPT can achieve a gain of 60.8% compared to the NOMA system and can achieve a gain of about 11.5% higher than that of the CNOMA system, which is more in line with the development concept of green communication.