D2D Resource Allocation Schemes Research Based On Fractional Frequency Reuse

With popularity of various mobile terminals,the fourth generation(4G)network will be difficult to meet the users' high demand for transmission rate in the next ten years,so 5G network research has been carried out.Device-to-Device(D2D)technology as one of the main technology of 5G network,which allows users to transmit data directly without through relay station so that it can reduce cell load,increase network capacity and decline communications time delay,so as to meet the needs of users.But if the D2D users have link transmission,at the same time,it will also bring serious co-channel interference to cellular link.According to interference problem,in this paper three resource allocation schemes which base on the theories and methods of mobile communication technology combined with research model were designed to improve the performance of the system.The main work of this paper can be included as follows:At first,a mode priority resource allocation scheme can be designed according to the work mode issue of D2D communication based on FFR(fractional frequency reuse).In this scheme,base station will allocate D2D users dedicated resource,and then allocate other users reuse resource.In addition,the base station will adjust the resource and link rate for the D2D users,so that each of the D2D users can be allocated the appropriate resource.Then,the edge area users may reuse the same frequency and cause interference issue in the traditional FFR resource allocation model,a band priority resource allocation scheme can be designed by dividing edge region into outer edge region and inter edge area.Dividing the frequency band of central region into three different sub-bands,the users located in different regions can be distributed resource prior to avoiding the problem of co-channel interference.At last,aiming to the trouble that D2D users were allocated resources randomly in the traditional works to make the communication resource utilization low,fuzzy clustering algorithm was put forward to group several D2D users in this paper.The D2D group can be formed through different character.Therefore,it can make the users belong to the D2D group to reuse the same cellular resources.At the same time,in order to ensure the cellular users' QoS(Quality of Service),cellular resource was optimal allocated for D2D group.The simulation results show that the proposed schemes can improve the performance of the system under three different situations.