Research And Simulation Of TD-LTE Dynamic TDD Technology And Interference Coordination

The TD-LTE system supports seven different UL-DL configurations, which can be adjusted flexibly from one to another based on different traffic loading. This is the advantage of TDD system compared with FDD system. However, only statically or semi-statically configured UL-DL configuration is used in current TDD network. With the application of heterogeneous LTE networks, different cells may have different traffic loading, if we continue to use the statically or semi-statically configured UL-DL configuration, we may not be able to meet the needs of different users’traffic demands, and it’s also a waste of resources to use this scheme.The basic principle of the Dynamic TDD technology is introduced, and the interference problem caused by the application of Dynamic TDD technology in the deployment scenario of HetNet is analyzed. A simulation modeling to analyze the performance effect caused by the application of Dynamic TDD technology is made, including the methods of the simulation, the metrics of the performance analysis and the procedure of the simulation.Then the system level simulation platform which is used in this thesis is given and the design methods of the main modules are described. The performance of the UL and DL of the Dynamic TDD technology is simulated respectively, and simulation results show that the impact caused by the application of the Dynamic TDD technology on the performance of UL and DL is very large, the DL performance is improved because of the decrease of interference that comes from adjacent DL cells, but the UL behavior is completely opposite. Dynamic adjustment of TDD UL-DL configurations makes the UL performance degraded severely. If we do not take any effective methods to reduce the interference, it can’t guarantee the normal communication of the UL.To solve the problem of UL caused by the application of Dynamic TDD technology, a cluster-based inter-cell interference coordination algorithm is proposed and the process of the algorithm is described in detail. And it is verified in system level simulation platform. Results show that after the cell cluster it can significantly improve the performance of the UL to use dynamic TDD technology, although the DL performance is a little degraded. The cell clustering algorithm gets the enhancement of UL performance at the expense of DL performance degradation. So we can say that the cell clustering algorithm is a trade-off algorithm, it makes the system which is serious differentiation to be balance by transferring part of DL performance advantage brought by the application of Dynamic TDD to UL. By this way, the system can use Dynamic TDD technology to adapt the traffic loading, and makes the UL and DL performance of the system are not much affected at the same time. So the cell clustering algorithm is effective in reducing the interference caused by the unsynchronized slot of UL and DL.