Research On Resource Allocation Optimization Algorithm Of NOMA Downlink System Based On Energy Efficiency

Rapid developments in areas such as artificial intelligence,the Internet of Things and big data analytics are all contributing to the explosive growth of data traffic and the massive connectivity of wireless terminals.However,the limited capacity of wireless communication systems,diverse service developments and massive device access are bound to create new technical challenges.Non-orthogonal multiple access(NOMA)is on the radar of many researchers to meet the high data rate demands and diverse service requirements of the future.With a new power domain dimension,non-orthogonal multiple access enables blocks of co-channel resources to be shared by multiple users,thereby increasing system capacity and spectrum efficiency.Considering that in the development of The 5th generation wireless system(5G)and future mobile communication technologies,wireless communication systems aim to achieve a balance between high capacity and low energy consumption,and that a rational resource allocation is crucial to maximise the potential benefits of NOMA systems,this paper presents a study of NOMA downlink systems for energy efficient resource allocation.This paper investigates the resource allocation scheme for energy-efficient NOMA downlink systems.For the problem of maximizing the energy efficiency of a single-cell multi-carrier NOMA downlink system,the paper decouples it into two sub-problems:the sub-channel allocation and the power allocation problem,taking into account the user minimum rate constraint and the maximum transmit power constraint.Firstly,in order to ensure high differences in channel gain within each sub-channel pairing user,and to improve the processing performance of the serial interference canceling(SIC)detector,this paper proposes a low complexity sub-channel assignment algorithm based on the worst-case sub-channel priority matching principle;secondly,this paper improves the particle swarm optimization(PSO),and The modified particle swarm optimization(MPSO)is further adopted to solve the power allocation problem.Simulation results show that the scheme has low complexity,can significantly improve the energy efficiency of the system,and can ensure better user fairness.For the energy efficiency maximization problem of a multi-cell multi-carrier NOMA downlink system,this paper decouples it into two sub-problems:joint user base station association and sub-channel assignment,and the power allocation problem,taking into account the minimum user rate constraint,the maximum transmit power and the user,base station and subchannel association constraints.Firstly,this paper transforms the energy efficiency maximization problem into a subtraction problem based on fractional programming.The Lagrangian dual method is also used to optimally solve the joint user base station association and sub-channel assignment problems.Secondly,successive pseudo-convex approximation(SPCA)is used to obtain an approximation to the power allocation problem.Then the Dinkelbach algorithm is applied to obtain the power allocation results.Simulation results show that this scheme improves the energy efficiency of the system and has lower computational complexity than that of the successive convex approximation(SCA)for power allocation.