Research On Resource Allocation Algorithm Of Non-Orthogonal Multiple Access System Based On SWIPT

The high-speed flourish of wireless communication technology has generated the dramatic demand of wireless network devices,and thus,it difficult for traditional wireless network technology to cope with future network demands.Non-Orthogonal Multiple Access(NOMA)is a multiple access technology that allows multiple users to multiplex on the same spectrum,hence cultivating the spectrum efficiency of the network.Simultaneous Wireless Information and Power Transfer(SWIPT)is a technology that can simultaneously transmit information and energy,as well as foster the energy efficiency of the network system via Energy Harvesting.Therefore,the core purpose of this report is to investigate the user pairing problem and power allocation problem hinged on the SWIPT of NOMA downlink network.The chief research contents are as follows:Research on the user's pairing problem based on the SWIPT of NOMA downlink network scenario.Applying SWIPT technology to cell center's users is to make the best of good channel's conditions of center users,therefore,this thesis proposes an algorithm for relay user selection and user pairing based on the distance between cell users and base stations and the distance between cell users.First,based on the distance between the users in the cell and the base station,the cell users are divided into two groups,namely central users and edge users;secondly,the distance between cell users is considered for user pairing,and the cell area is divided into four areas,corresponding to each the first,second,third,and fourth quadrants in mathematics,and then the center users and the edge users were paired according to the best-near best-far(BNBF)user matching algorithm in each restricted area.The simulation results reveal that the best-near-best-far user pairing algorithm based on the restricted domain significantly outperforms the random pairing algorithm and the BNBF pairing algorithm,which significantly improves the interruption performance of the edge users.Based on the single input single output(SISO)scenario of the SWIPT-based NOMA downlink network,the power allocation problem for optimizing the total sum rate of the system is investigated under the premise of satisfying the quality of service(Qo S)of communication for cell edge users.Based on the fact that this problem is a complex nonconvex problem,it has a high complexity for jointly solving the power allocation factor among NOMA users and the power splitting factor problem for relay users to achieve the globally optimal solution.In this thesis,we propose a step-by-step power allocation scheme to decouple the joint power allocation factor and power splitting factor problem into a typical NOMA user power allocation problem and a relay user power splitting problem,thus converting the complex nonconvex problem into a less complex mathematical problem,which can be solved by Lagrange multiplier method and mathematical function analysis method.Simulation results show that the performance of the proposed scheme in this thesis approximates the algorithm of the globally optimal solution,and effectively solves the power allocation problem of the system.