Research On Dynamic TDD Technology Of LTE Mobile Communication Network

The long term evolution (LTE) project is a smooth transition of3G to4G, which is planned by3GPP (the Third Generation Partnership Project).TD-LTE (Time Division-LTE) is one of mobile communication technology and standards which developed by Alcatel-Lucen、Nokia Siemens Networks、Datang Telecom、Huawei Corporatio、n ZTE Corporation and China Mobile. TD-LTE uses time-division duplex working mode, and suits for dynamic distribution channel According to the asymmetry of network traffic. LTE can overcome the interference inside the cell, because LTE use OFDM (Orthogonal Frequency Division Multiplexing) technology. Due to the LTE tend to adopt frequency reuse factor as one or close to one, cause ICI (Inter-Cell Interference) very seriously. TD-LTE not only exist regular interference, but also exist the user to user interference and the interference of base station to base station. Therefore, how to reduce the Inter-cell interference, and improve the spectrum efficiency becomes the TD-LTE urgently problem which needs to solve.This paper introduces the LTE and the theoretical basis such as the network architecture. A deep analysis about ICI of TD-LTE will be given and several kinds of mainstream interference control method will be introduced. This paper also proposes interference control methods of Pico separated deployment scenarios and Macro-Pico heterogeneous network scenarios.In the same frequency Macro-Pico cell heterogeneous networks, how to coordinate frequency allocation of Macro cell and Pico cell become a key issue of interference control. In this paper, the interference between Macro cell and Pico cell will be analyzed. On this basis, a mixed frequency reuse scheme will be proposed based on soft frequency reuse for Macro-Pico cell heterogeneous network scenarios. Simulation results show that the proposed method can improve the Pico cell performance such as throughput and Signal to Interference plus Noise Ratio. Currently, generally use static slot algorithm and cell clustering interference mitigation algorithm for Pico separate deployment scenarios. The whole network will be a cluster when Picocell dense deployment for cell clustering interference mitigation algorithm. It makes no difference with static slot algorithm. ABS (Almost Blank Subframe) configuration algorithm based on graph theory will be proposed for solve the problem of interference between base stations. Additionally, this paper will define cross-slot interference area and restrict user access to uplink resources in cross-slot interference area for user-user interference of cell edge. The simulation results show that the proposed algorithm can improve the throughput of the whole network compared with static slot algorithm.