Energy Efficiency Optimization For Mobility Management In Heterogeneous Network

In the deployment and industrialization of the third and fourth generation wireless communication network, bandwidth and capacity have put a limit to satisfy the requirements of multimedia services. In order to cope with large burst data traffics, Small cells, including Micro cell, Pico cell, Femto cell and Remote Radio Head (RRH) are introduced into Macro cell to improve network performance and achieve load balance. However, the dense deployment of Small cells challenges the mobility management in Heterogeneous networks (HetNet) and increases system power consumption. Therefore, enhanced mobility management and energy saving strategy should be studied. This thesis mainly researches on the mobility management in HetNet, and optimizes the system energy efficiency. Research contents are summarized as follows:Considering challenges in the mobility management in HetNet, this thesis analyzes the factors affecting handover failures in HetNet. A new measurement report trigger event is designed for earlier entry of handover procedure to avoid handover failure. By counting the fast drop event of signal, user judges if the upcoming handover is mature, and user triggers the measurement report immediately if the counting value surpasses a certain threshold. Simulation results prove the proposed scheme reduce the handover failure rates and Ping-Pong rates over current standards.Considering the delay in handover process brought by dormancy strategies, this thesis analyzes the effect of discontinuous transmission and reception strategies to the mobility management performance. A coordination scheme between these two mechanisms is proposed to support the mobility management and improve energy efficiency. In this scheme, the cell-ON duration time of discontinuous transmission and reception mechanisms is grouped and aligned. Simulation results indicate that the proposed scheme reduce the network power consumption.Because the dense deployment of HetNet will enlarge energy consumption, a control plane (CP) and user plane (UP) adaptation scheme under frameless network architecture (FNA) for the HetNet is designed. The CP/UP separation and adaptation with constraints is presented and the CP/UP dynamic construction and deployment scheme is proposed via the Voronoi Diagram with energy efficiency optimization based on user distribution. Based on the observation of simulation results, the proposed CP/UP separation and adaptation scheme surpass the current scheme.