Research On Resource Allocation Based On Energy Efficiency In SCMA System

With the massive increase of mobile terminal connections,the shortage of spectrum resources cannot cope with the increasing diversified service demands,and the increase of access devices brings great energy loss to the access network.Applying Sparse Code Multiple Access(SCMA)to the 5th Generation mobile communication technology(5G)can better improve access density and spectrum utilization of users.In the context of advocating green communication,improving the energy efficiency of access network will be of great significance.Therefore,this thesis focuses on the study of energy-efficient resource allocation in the SCMA downlink system.The details are as follows:In the single-cell multi-user SCMA downlink system,in order to maximize the system energy efficiency,an iterative optimal allocation algorithm joint codebook and power is proposed.Firstly,a codebook assignment scheme based on the system energy efficiency gain is designed in the case of the given power allocation.Secondly,when the codebook assignment is given,the power allocation problem is converted into a convex optimization problem,which can be solved by Lagrange dual function.Finally,according to the idea of iterative optimization,the codebook and power are allocated iteratively until convergence.The simulation results show that the proposed algorithm has obvious advantages over the existing schemes,and it can effectively utilize system resources to improve energy efficiency.Fairness plays a very important role in service quality assurance,which is important indicators for evaluating user experience.Therefore,this thesis presents an energy-efficient resource allocation scheme under proportional fair guarantee.In order to reduce the complexity,the resource allocation problem is divided into two sub-problems to solve separately.In the codebook assignment phase,the user's priority is determined by the difference between the current user rate and the minimum rate requirement,and the minimum rate requirement of user is satisfied with as few codebooks as possible.Then,the user with the worst rate fairness after the update is searched,and the codebook is assigned in turn to satisfy rate proportional fairness of the user as much as possible.In the power allocation phase,according to the obtained codebook assignment scheme,the power allocation under the approximate optimal energy efficiency is obtained by the bisection method under the requirement of satisfying the user rate.The simulation results show that the proposed algorithm can achieve better energy efficiency performance on the premise of ensuring rate proportional fairness.