Research On The Key Technology Of D2D Radio Resource Management In Lte System

With the rapid development of mobile telecommunication, the number of subscribersis growing explosively, and the requirement of data traffic is improving correspondingly, which both leads to the birth of LTE, a revolutionary new wireless technology. However, considering the network capacity and spectrum efficiency, it is still has room for improvement. As a new telecommunication technology for short distance, Device to Device(D2D) allows the traffic to be transmitted between user equipments directly under the control of base stations, which could improve spectrum efficiencyas well as the transmission data rate of the whole cell, and to reduce the workload of base station and the energy consumption of mobile station.However, the reuse of resources brings in severelyinterference between links and between cells. It is one of the key challenges to manage resources in wireless communication to control the interference between links and assure thecommunication quality of cellular link.This paper focuses on the key technology of D2D radio resource management in LTE system. New algorithms of mode selection, power control and resource allocation are proposed to reduce the interference between D2D and cellular and to improve the performance of system. The key research results are as follows:Firstly, the improved algorithms of mode selection and resource allocation are proposed. Mode selection is to choose the proper communication mode between D2D mode and cellular mode for D2D equipment. Proposed mode selection algorithm is based on the path loss of D2D links and interference between D2D and cellular links. For selecting the sharing resources with low interference from cellular link, we present interference-limit round-robin scheduling resource allocation algorithm based on Quality of Service (QoS), which is controlled centrally by establishing resource pool.Secondly, three improved algorithms of power control are proposed and compared. Power control is to control transmission power of cellular and D2D links in order to limit inter-cell and inner-cell interference between D2D and cellular. Open loop and close loop combined power control algorithm is proposed based on path loss, then three schemes are compared based on the fixed transmission power, the fixed received power and the fixed target SINR (Signal Interference Noise Ratio).Thirdly, system-level simulation of improved algorithms is completed. D2D simulation platform is set up to do system-level simulation of the three algorithms mentioned above with multi-cell topology. The results show that in different link distance scenarios, the radio resource management of D2D can be realized effectively with the well-designed algorithms in this paper.