DL-UL Interference Management And Traffic Adaptive In TD-LTE System

With the popularity of smart mobile devices and the exploding of multimedia data traffic, the requirements for faster wireless communication have increased dramatically. In such new scenarios, the UL/DL traffic load in a cell may fluctuate rapidly within the time and space domain, which requires the communication network to support dynamic configuration of subframes according to the UL/DL traffic load. Compared with FDD communication systems, the TDD network has significant advantages in traffic adaptation since it can provide more flexible network deployments. In traditional TD-SCDMA networks, the dynamic changes of UL/DL traffic is not supported and thus a serious UL/DL cross interference may occur in different cells. Therefore, in3GPP RAN51st meeting, a new research topic called "the enhanced TDD LTE research on the DL-UL adaptive interference management and operations" has been started, aiming to support the dynamic subframe configurations in TDD networks.This thesis mainly focuses on the following two aspects related with the dynamic subframe reconfigurations in TDD network.Firstly, the dynamic reconfiguration of subframes will bring two additional cross UL/DL interference. This thesis studies this problem in both homogeneous and heterogeneous networks and analyses the interference model in both scenarios. For the homogeneous macro deployment, we proposed a TDD dynamic reconfiguration scheme of subframes which is based on region division.For heterogeneous layered network deployment, this thesis proposes interference suppression strategies based on cell clustering and adjacency list respectively. Multi-core parallel system-level simulation platform is built to support for TDD uplink and downlink co-simulation. Through simulation, the above strategy can achieve better performance gain. Secondly, when TD-LTE re-configure among the7different UL-DL configuration, there will be conflicts mapping UL sub-frames and DL sub-frames in margin frame’s HARQ process。This problem is solved by the higher layer in the existing standards. However, in the situation of dynamic reconfiguration, it will affect the efficiency of communication heavily due to the small reconfiguration interval. This By analyzing the relationship among the7different UL-DL configuration, we propose detailed solutions to the problem of PDSCH/PDCCH HARQ、PUSCH HARQ and UL-Grant when re-configure. Our solution achieves a smooth UL-DL reconfiguration as well as guarantees the communication efficiency.