Research On Resource Allocation And Throughput In LTE-A Relay System

The mobile communication industry is the fastest growing industry in the number of users in the world.After the evolution of 2G,3G and 4G,the mobile communication system will usher in a faster,denser,more intelligent 5G era.With the evolving process,the mobile communication technology continues to upgrade and update,including a very important technology – the relay technology introduced by the LTE-A standard.To meet the demand of people’s Internet anytime and anywhere,relay is indispensable.The relay is a low-cost,easy-to-deploy wireless device which can expand coverage and increase capacity.However,it may generate interference to the direct users and destroy the fairness of the cellular system.To solve the problem,the resource blocks(RBs)used by all users are orthogonal in many existing schemes.Although these schemes avoid the interference,the spectral efficiency is low.On the basis of guaranteeing the quality of service for all users,the thesis presents NPF and NRA schemes to increase the spectral efficiency and the throughput,ensure a good fairness.NPF’s basic idea is to bundle the backhaul link and access link into a virtual user,and the direct link as a virtual user.Firstly,in a scheduling frame,all virtual users acquire RBs with the PF scheduling to ensure the fairness of the cellular system.Then the RBs are further allocated to the backhaul link and the access link in two time slots,so that the system throughput is maximum.NRA’s basic idea is that the RB used by the relay user’s access link and the direct user is non-orthogonally shared.Firstly,in the second time slot,each access link selects the optimal direct link to share the RB,which is to ensure the minimum disruption of the fairness of the cellular system.Then the remaining RBs are allocated in turn to the backhaul links and the direct links so as to maximize the whole system throughput.Simulation results show that compared with the traditional PF scheduling scheme,the two schemes reduce the interference with the direct users,improve the fairness and the throughput of the whole cellular system,and increase the spectral efficiency.