Research And Simulation On Inter-Cell Interference Coordination Technology In LTE System

In the wireless communication system, it will inevitably lead to the inter-cell interference if the same frequency resource is simultaneously communicated among different cells. Long Term Evolution(LTE) system generally adopts same frequency networking scheme, which makes the problem of inter-cell interference more serious. In order to suppress such interference, some effective interference suppression scheme, such as fractional frequency reuse, soft frequency reuse and coordinated multiple point transmission and reception technology, have been widely studied in the LTE system.First of all, the research background and significance of inter-cell interference suppression technology are introduced and kinds of the inter-cell interference suppression technology are summarized in the thesis. Then, the thesis focuses on the inter-cell interference coordination technology and introduces it respectively from the aspect of the static, dynamic and semi-static.Secondly, the thesis pays attention to the adaptive fractional frequency reuse which belongs to the semi-static inter-cell interference coordination technology. Then, it simulates and analyzes the impact of frequency division, user partitioning and scheduling algorithm on the system performance. On the basis of this work, an adaptive fractional frequency reuse scheme based on frequency division is given and simulated on two scenarios which are scenarios under heavy load at cell center and heavy load at cell edge. The simulation results show that the given scheme can effectively improve the system of fairness under high load at cell center, however, it can not make it under high load at cell edge.Finally, the thesis designs an adaptive fractional frequency reuse scheme based on dynamic user partitioning and coordinated scheduling among cell center users. Under the condition of high user load at cell edge, most users suffer strong interference. If it just simply uses dynamic user partitioning scheme, some users which have strong interference but lower interference than other users, classified as cell center users, still suffer co-channel interference. In order to solve this problem, the designed scheme combines the idea of the cooperation with fractional frequency reuse technology and suppress the co-channel interference of center users by use of coordinated scheduling among center users in cooperating set and the extension of the use of boundary resources, which improves the frequency spectrum utilization at the same time. Due to the multiple collaboration occurs in the same base station site area, the collaboration has advantages of small signaling overhead, low delay, etc. Then, simulation and comparative analysis of system performance of the designed scheme and other schemes are performed. The simulation results show that, the designed scheme has the strong adaptive capability which enables system to adapt heavy load variations, and provides better performance in the improvement of the cell edge user throughput and average throughput of the whole system users in the scenario of uniform distribution of users.