Research On Intercell Interference Coordination Technology In LTE System

Inter-cell interference(ICI)is caused by the network planning strategy unreasonable.In order to satisfy the higher data rate and spectral efficiency,the LTE system network planning to abandoned the traditional frequency reuse method.However adopted a larger frequency multiplexing reuse factor will have serious inter-cell interference,especially affecting cell-edge user performance.LTE systems with high data rate use OFDM technology can effectively reduce intra-cell interference,but inter-cell interference severely restricts the quality of service of LTE network users.Inter-cell interference coordination technology(ICIC)is the mainstream technology for solving ICI problems.Its core is to achieve the goal of avoiding or mitigating ICI by planning system resource blocks and power.It has the advantages of obvious performance improvement,flexible use and simple implementation.Partial frequency reuse(FFR)and soft frequency reuse(SFR)are two classical solutions in interference coordination technology.This paper focuses on inter-cell interference problem,investigating the FFR and SFR technology which the main research contents are as follows:1)Firstly,we introduce the development and evolution of LTE system for the inter-cell interference problem,look forward to the future 5G network and describe the SFR technology and FFR technology.Meanwhile aiming at the problem of cell modeling in LTE system,a simulation model of LTE system was established by Matlab,which provided the experimental basis for the research of soft frequency reuse.2)In view of the optimal network planning problem of LTE system,this paper analyzes and plans the static SFR resource allocation in detail from the aspects of cell division,user division,resource allocation and power control,and theoretically analyzes the interference model build.Finally,taking the system throughput index as criterion,the optimal radius ratio and power ratio of soft frequency reuse technology are obtained by combining the simulation results and theoretical analysis.3)According to the ICIC classification problem,from the indexes of system throughput,outage probability and cell area percentage analyzed and compared the three schemes of FRone,SFR and FFR,which contain the characteristics of the three schemes and their system performance.It can be concluded that FFR and SFR can improve the performance of edge users,but the performance of central users will decrease through comparing with FRone.SFR balances the interference and total system performance,greatly improving the worst user rate and reduce the total system outage probability compared with FFR.4)Aiming at the problem of static SFR resource allocation,according to the dynamic change of the power control value ? and the ratio K of the distance between the center user and the base station,we give five kinds of different power control value ? and distance ratio K as a function of the program.Finally come to the appropriate power control value ?selection scheme to determine the transmit power of different central users.The results show that it has some advantages in improving cell throughput,reducing the probability of outage and improving the area percentage of the cell compared with the static SFR technology when the value ? and the value K with a linear relationship.It can further improve the overall performance of the cell through Matlab simulation and numerical analysis under the different dynamic power control SFR power control value selection scheme.