Research On Joint Resource Allocation Scheme Of NOMA System

By useing superposition coding and successive interference cancellation technology,NOMA has higher system performance than OMA.However,previous studies usually only consider power allocation,resulting in insufficient resource utilization.Moreover,they usually take the system rate maximization as the only goal,ignoring the edge user rate and user fairness.This thesis considers system throughput,user rate,user fairness and other requirements,and conducts related research from the perspective of joint resource allocation to achieve the sufficiency and fairness of resource utilization.The main work of this thesis is as follows:1.By amending the energy efficiency maximization scheme,a compromised scheme is proposed to satisfy both energy efficiency and user fairness.When the transmission power of base station is increased,part of the power is allocated to the cell-edge users.Hence,the minimum user rate can be improved,which guarantees the information transmission rate of the cell-edge users and meets the need of user fairness.The simulation results show that the scheme satisfies the average EE lower limit on the premise of improving user fairness.At the same time,the energy utilization ratio of the base station is close to 100%,which realizes the efficient utilization of the base station energy.2.The compound problem of resource block and power allocation in NOMA system is studied,a scheme to dynamically determine the resource block allocation between user groups and the power allocation coefficient whithin each user group is proposed,so as to effectively reduce the computational complexity of exhaustive method and obtain the largest system ASR.First,considering the power allocation within the user group,the expression of the optimal power allocation coefficient about the number of resource blocks in the user group is derived.Then,the dynamic relationship between the system ASR and the number of resource blocks of each user group is considered.Finally,in the process of resource block allocation,the system obtains the maximum ASR by dynamically changing the resource block and power allocation.Simulation results show that this method has the same ASR performance as NOMA exhaustive search,which is much higher than NOMA random assignment,OMA exhaustive search and OMA random assignment.At the same time,the computational complexity of this method is far lower than exhaustive search,which shows the superiority of this method.