Research On Downlink Resource Allocation Algorithm For NOMA System Based On Energy Efficiency

With the rapid development of mobile Internet and the explosive growth of artificial intelligence applications,the massive access of intelligent devices and the surge of data traffic lead to a sharp rise in the cost of energy consumption of wireless communication system.A new paradigm of wireless communication is called for in order to provide communication services with higher energy efficiency.Non orthogonal multiple access(NOMA)technology has the advantages of high spectrum efficiency,low transmission delay and strong connection ability.It is expected to serve many mobile cellular users with massive data traffic transmission.In NOMA system,resource allocation schemes such as channel and power affect the energy efficiency performance index of the system to a great extent.How to improve the energy efficiency performance of NOMA system has become a research hotspot in the domain of communication in recent years.Therefore,this thesis mainly studies the resource allocation scheme of NOMA system based on energy efficiency.Aiming at the problem that multi-user shared resources on the subchannel of NOMA system will produce interference and affect the system energy efficiency,a joint subchannel and power allocation scheme is proposed.Firstly,an improved user subchannel two-side dynamic matching algorithm based on matching theory is proposed,and the concept of two-side exchange stability is introduced to solve the problem of interference between users multiplexed on subchannels,so as to realize the dynamic matching between users and subchannels to meet more user access requirements;Then,the power is allocated by difference of convex(DC)programming algorithm;Finally,the simulation results show that,compared with the traditional matching algorithm,fractional transmit power allocation algorithm and orthogonal frequency division-multiple access scheme,the proposed scheme can better improve the energy efficiency performance of the system,and convergence rate is faster.To further improve energy efficiency of the NOMA system and the quality of service of cell users,aiming at the power allocation problem of users in a single subchannel of NOMA system,due to the high complexity and computational overhead of previous power allocation algorithms,a power allocation scheme for NOMA system based on improved whale optimization algorithm is proposed.Firstly,the constrained optimization model of power allocation based on energy efficiency is established,and the penalty function is used to deal with the constraints,so as to construct fitness function to solve the energy efficiency optimization problem;Then,the simulated predation behavior in whale optimization algorithm is used to complete the search,and its convergence factor and inertia weight are improved to prevent falling into premature convergence and local optimization.Finally,the simulation results show that,the algorithm proposed in this thesis not only reduces the computational overhead,but also outperforms the comparison method in terms of energy efficiency.