Research On Cooperative NOMA Resource Allocation Strategy Based On Particle Swarm Optimization Algorithm

With the arrival of the 5G era,people have higher requirements for the transmission rate and service quality of mobile communication.However,the explosive growth of business volume and user numbers has led to the shortage of spectrum resources and excessive energy consumption in mobile communication.The Non-Orthogonal Multiple Access(NOMA)technology can effectively improve the system’s spectrum utilization by utilizing the characteristics of spectrum resources sharing.The Device-to-Device(D2D)technology utilizes the advantage of direct information transmission between users,reducing the pressure of excessive load on base stations.The Simultaneous Wireless Information and Power Transfer(SWIPT)technology can simultaneously transmit energy and information,thereby reducing the energy loss of signals during transmission.This study applies D2D and SWIPT technologies to NOMA collaborative networks,further improving the transmission quality and energy efficiency of communication systems through resource allocation algorithms.The research work of this thesis mainly includes the following two points:(1)For the D2D assisted NOMA relay collaborative communication system(DC-NOMA),the reachable rates of signals received by users in different time slots were analyzed,and an expression for the traversal capacity of the DC-NOMA system was derived.In order to improve the performance of the system,an optimization problem is formulated to maximize the system ergodic capacity.The Particle Swarm Optimization(PSO)algorithm is employed to design the optimal power allocation strategy.The most appropriate power allocation factor is obtained for each user,and then the maximum system ergodic capacity is achieved.Simulation results show that the proposed PSO power allocation scheme can improve the system capacity and outage performance.(2)For the Simultaneous Wireless Information and Power Transfer Non-Orthogonal Multiple Access(SWIPT-NOMA)system,in order to improve the energy efficiency of the system,the achievable rates of the users receiving information in the direct connection and collaboration modes of the SWIPT-NOMA system are analyzed,and the expressions for the energy efficiency of the system network in two modes are derived.The optimization problem is constructed with the objective of maximizing the energy efficiency of the SWIPT-NOMA system under the ensuring the minimum rate of users,and the power allocation coefficient of NOMA users and the power splitting factor of SWIPT are optimized by using particle swarm algorithm to find out the optimal energy efficiency of the communication system.The simulation results show that the energy efficiency optimization strategy based on particle swarm algorithm can find out the optimal energy efficiency of the system with lower computational complexity compared with the traditional algorithm.