Design And Implementation Of Mobility Management Based On WiMAX Access Gateway

WiMAX is broadband wireless access MAN technology,which based on IEEE802.16 series of standards,its original purpose is to provide point to multipoint broadband wireless access in the metropolitan area and multi-vendor environment. WiMAX can provide high bandwidth data transmission and high-mobility management with advantages such as standardization, mature technology, high transmission speed, large coverage, better performance of resisting rain attenuation, and flexible networking.The study of mobile handoff technology in WiMAX network layer architecture contributes to the networking and deployment of WiMAX. Based on the End-to-End Network Syetems Architecture Stage 2 and Stage 3 standards issued by WiMAX Forum, the design and implementation of handoff management of WiMAX gateway is carried out and a mechanism for fast handoff is proposed in the thesis.The main contents of the thesis are displayed as follows:(1) According to the WiMAX network standards, analyzing the functions of ASN-GW and each module entities and writing the requirement analysis of the handoff module and context module.(2) Based on the requirement analysis, we design the program flow and write performance function. By discussing the communication interfaces with other modules, we determine the communication content, and write interface functions and related parameters. And then we achieve the preliminary design of the handoff module and the ontext module.(3) Write and debug the software program of the handoff module and the context module in Linux. Take BS simulator as base stations as well as set up HA and AAA Server environment, and then run the gateway program and carry out functional testing and stress testing. Meanwhile we verify the message flows of the handoff module and context module by using the Wireshark sofeware.The thesis focuses on analysis and study of WiMAX handoff management and reduction of the handoff delay. According to the WiMAX network standards,the handoff management of gateway is achieved. There are two innovation points: first, the gateway MIPv4 registration process is achieved by the combinations of the PMIP Client and DHCP Relay. The IP distribution and management is charged by the DHCP Server and relayed by the DHCP Relay. MIP registration Client is set in the Gateway by using the PMIP Client, which reduces the complexity of MS design and contributes the popularity of MS. Second, in order to reduce the handoff delay, a mechanism that combines the context transfer protocol and authentication process is proposed. The mechanism reserves the AK, MSK and MIP_PK key information in the initial accessing the network by using the context module. When the occurrence of MS inter-network handoff leads to the re-access network and results in the re-authentication, according to the number of authentication controlling by the lifetime of key, it avoids the unnecessary re-authentication and then reduces the handoff delay.The test results show that the design achieves the control process of the handoff management module of the WiMAX gateway. When the MS occurs inter-gateway handoff, the mechanism can reduce at least 0.42s delay, which optimizes the handoff performance.