Research On Resource Allocation Algorithm In Non-orthogonal Multiple Access Systems

At present,traffic services such as Internet of Things,"cloud" applications and big data are rapidly developing,and the number of mobile users and network coverage are also continuously increasing,which increases the rate requirements of wireless communication systems and shortages of wireless resources.The non-orthogonal multiple access(NOMA)technology has not only changed channel exclusive features of traditional orthogonal multiple access(OMA),but also has excellent spectral efficiency and user capacity,so that the research on the efficient resource allocation in NOMA system has become one of the hot topics in 5G green communications.This paper analyzes the resource allocation algorithm of downlink multi-user NOMA system from two aspects of economic efficiency and energy efficiency.On the one hand,based on the economic theory of pricing mechanism related to resources allocate,a price-based power allocation with rate proportional fairness constraint in downlink NOMA systems is proposed to optimize the base station revenue.Firstly,model problem as maximizing base station revenue according to Stackelberg game between base station and user;Then convert the optimization problem into the power allocation and rate allocation in turn;And then introduce an auxiliary variable to simplify calculation;Finally,use the dichotomy to solve the optimal solution,and achieve the optimal rate,the optimal power,the optimal power price of each user and the optimal base station revenue.The simulation results show that the proposed algorithm has significant advantages in terms of user fairness index while optimizing the revenue of base stations,which has a good theoretical guidance for the price-based NOMA resource allocation algorithm.In addition,in order to reduce the energy consumption of NOMA system and enhance the user fairness,an energy-efficient power allocation with rate proportional fairness constraint in non-orthogonal multiple access systems is proposed to achieve the optimization goal of the system energy efficiency.The algorithm first models the problem as maximizing system energy efficiency under the constraints of user QoS and user fairness;Secondly,the problem is transformed into the rate allocation,and the auxiliary variables are introduced to facilitate the calculation;And then,the fractional programming and Dinkelbach algorithm is adopted to further convert the problem and the inner-outer two-layer iterative method which respectively updates power and energy efficiency respectively to is used to solve optimal solution;Finally,the algorithm is verified by computer simulation.And simulation results show that the proposed algorithm has better performance in terms of system energy efficiency than two optimal allocation algorithms of NOMA-Rmax and NOMA-Pmin.