Research On Resource Allocation Method Of D2D Communication In Small Cell

In response to the continuing rapid growth of mobile data traffic,5G communication technologies such as millimeter wave technology,Device to Device(D2D)technology,and small cell technology have attracted the attention of many scholars.Therefore,the next generation of 5G networks is likely to be a hybrid network where multiple technologies exist at the same time.As a kind of high frequency transmission technology,millimeter wave has abundant spectrum resources and can be used to solve the current shortage of spectrum resources.The 5G network that combines millimeter wave technology with D2 D technology will gain the advantages of high bandwidth and system throughput.And because the coverage radius of millimeter wave network is smaller,it is more advantageous to apply it to small cell network.Therefore,this thesis mainly studies the resource allocation in hybrid small cell networks composed of millimeter wave networks and D2 D communication.In order to reduce interference caused by D2 D users reusing downlink cellular resources in the outdoor millimeter wave cellular network,this thesis presents a D2 D resource allocation method based on minimum overall interference.Firstly,a linear programming approach is used to obtain a reusable set of each D2 D user.Secondly,the optimal transmit power is obtained through the power control of D2 D users.Finally,a resource allocation algorithm based on the overall minimum interference is proposed to ensure the communication quality of cellular links and to get the optimal allocation result by using the Hungarian algorithm.The simulation results indicate that compared with existing schemes,the proposed algorithm can effectively reduce the interference and improve the system performance.In order to solve the problem of optimal allocation of D2 D users reusing uplink cellular resources in the outdoor millimeter wave scenario,a D2 D resource allocation method based on bipartite graph is presented in this thesis.Firstly,the admission set of each D2 D user is find out through linear programming method.Then,power control is performed on the D2 D user to select the optimal transmit power.Finally,a multi-stage matching algorithm based on bipartite graph is proposed to allocate resources for D2 D users,and use the optimal match(KM)algorithm multiple times to derive the allocationresult.The simulation results reveal that the system throughput and spectrum utilization of the proposed algorithm can be improved effectively.In order to reduce the interference between D2 D users and cellular users in the millimeter wave cellular uplink,a low complexity D2 D resource allocation algorithm based on interference suppression is presented in this thesis.Firstly,according to the principle of maximizing the total data rate,a reused cellular user is selected for each D2 D user,thereby a candidate D2 D set for each cellular user is obtained.Then,the D2 D user is allocated resources by the interference threshold requirement and the limitation on the quantity of D2 D users reusing the same cellular resources.The simulation results indicate that the proposed algorithm can effectively improve the system throughput.