The Research Of Coordinated Multi-Point Transmission In LTE-Advanced

With the rapid development of mobile communications,towards the next-generation of wireless network, people put a higher transmission rate, greater system capacity and wider coverage of the business needs, The standard of the LTE-Advanced system aim at meeting even exceeding the requirements of the proposed transmission rate, capacity and other requirements specified by the ITU-R defined in IMT-Advanced.In LTE-Advanced System,downstream transmission rates should achieves up to 1Gbit/s, and upstream should up to 512Mbit/s.the most important thing is that the cell edges should also provide high-speed data rates and wider coverage. The Technology of CoMP introduced in LTE-Advanced System reduce Inter-cell interference,improve the spectral efficiency of the overal system especially the spectral efficiency of the cell edge through the exchange of control information or share of user data between multiple cell, reducing interference significantly.This article researchs on the technique of Coordinated Multi-Point transmission in LTE-Advanced such as random access technology, Coordinated Multi-Point transmission/reception scheme, the feedback of information, the user data processing and the impact of high-level signaling necessary for cooperative multi-point transmission to the existing signal in LTE.First, according to the characteristics of the network structure of CoMP, this article proposed a method of multiple point random accessing which take the advantage of interacting of control signaling and user data between multiple transmission point. High priority UE of cell edge can initiate independent random access procedure to both resident and candidate base stations at continuous time slot. Through this method,the high priority UE of cell edge can achieve higher success rate and a shortened delay in this process. And then simulation was product to verify the proposed multiple random access method.Second, studying the user plane protocol stack data processing in depth,and then analyzing and summarizing the research result in the problem and difficulties be solved to accomplished the CoMP.Finally, after the analysis of the problem faced in Coordinated Multi-point transmission/recption, giving basic signaling procedures for distributed scheduling and centralized scheduling, then proposed two optimized signaling procedure respectively.At last from the point of view how the delay of X2 affect the overall system throughput,a comparison was made througth simulation of the four signal procedure.