Research On Key Techniques Of Device-To-Device Communications In Lte-Advanced System

With the evolution of LTE-Advanced system, the traditional transmission mode, where a Basic station acts as the center of communication, has limited the performance of the cellular system. The introduction of D2D communications can effectively enhance the cell coverage and improve transmission performance. However, there is no doubt that the introduction of D2D communication will bring additional interference. Therefore, this paper focuses on the power control techniques in D2D communication, combined with adaptive modulation and coding scheme and HARQ technique, to ensure the transmission quality of the entire system.This paper firstly gives a brief introduction of the LTE-Advanced system, analyzes the key techniques in TD-LTE-Advanced, and then focuses on the analysis and research of D2D system performance. The work on the D2D system performance studies can be mainly divided into three areas. First of all, this paper analyzes transmission characteristics of D2D system, conducts some research on power control technique and introduces a power control method for D2D communication in cellular systems. Subsequently, a system level simulation platform is built to support more researches. At the same time, this paper gives the simulation results of the enhanced technique named VMIMO and the HTTP traffic model. Finally, scheme design and detailed simulation analysis are given to evaluate the system performance of the D2D communication system. Simulation results show that the improved open loop power control scheme can effectively enhance the whole system’s performance while the adaptive modulation and coding scheme and the HARQ technique are able to bring the D2D communication system performance improvement.Finally, conclusions and future research direction of D2D communications are summarized.