Key Techniques Of D2D Communication Based On LTE-Advanced System

IMT-Advanced system has formulated the standard and research direction for mobile communication in the future. As one of the candidate techniques, LTE-advanced system has set up a specialized research topic for D2D communication. Based on the research achievements on D2D communication around the world, the issue aims at introducing the D2D communication to the uplink of LTE-Advanced system. At the same time, this paper will also focus on the analysis of the general gain that different key techniques bring to the system.At first, the paper makes a brief introduction about the progress and basic knowledge of LTE-advanced system, and analyzes several key techniques in this field as well. Then the issue runs a system-level simulation on the basis of the system simulation platform, which produces the data supply for the follow-up work. The main work of the paper is as follows:Firstly, taking the complex scene which adds a number of D2D users within each cellinto account,also considering different ways of distribution, the paper will analyze the MCS (Modulation and Coding Scheme) level of D2D communication userbased on different situations. The paper will make a conclusion about the introduction of higher MCS level for D2D communication.Secondly, after the introduction of D2D communication into LTE-Advanced system, the most basic principle is to minimize the "interference between D2D communication and traditional cellular communication. Therefore, while the D2D users reuse the uplink frequency source, research on an appropriate power control is imperative.In the paper, considering single cell and single RB, the overall utility function is proposed. Thenthe paper analyzes and proves its correctness. After times of iterations, the user power will be shown. This scheme can effectively reduce the interference between different communications and improve the system throughput.Finally, based on3GPP network protocol, paper proposes a scheme, which is the way of connection between UE and eNB(evolved Node B) using Relay UE. And then, the paper integrates Relay, MBMS (Multimedia Broadcast Multicast Service) and D2D, propose a scheme of D2D group cooperated retransmit. This scheme applies to the situation that multiple D2D users share the same data from eNB. This scheme can effectively reduce the load and improve the efficiency of data transmission in the same period of eNB.