The Implementation Of WiMAX Medium Access Control Layer In EPON And WiMAX Integrated Access System

In recent years, with the emergence and development of the high speed and strict quality requirement services, such as IPTV, HDTV and Online Games, the requirement for bandwidth grows rapidly. The operators become to focus on broadband access network building. The fiber optical communication system provides high bandwidth but convenience is not enough. On the other hands, the wireless communication is convenient but its bandwidth is restricted. So the convergence of fiber and wireless network becomes the development trend of access networks. The integration of wireless access and fiber access is in good accordance with the trend of the access network. The integration of EPON and WiMAX is one of the important techniques of the optical and wireless integration.In this paper, the designing and development of the embedded software of WiMAX MAC layer for EPON and WiMAX integrated access system are accomplished, and an improved sheme for WiMAX MAC ARQ mechanism is proposed. The whole work is supported by National 863 project "The key technology of dynamic heterogeneous integrated access network supporting P2P and multicasting" and Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry project "A new traffice driving packet transmission and access network architecture and the key technologies reseach".The major works of this paper are listed as follows.1)The requirements analysis and software designing of WiMAX BS MAC layer embedded software, which based on AMCC powerPC 460ex evaluation board and Linux operation system, are accomplished, and the uplink and downlink data processing sub-modules development are completed.2) The requirements analysis and software designing of WiMAX SS MAC layer software, which based on x86 personal computer and Linux operation system, are accomplished, and the whole software development is completed.3) The system test on the EPON-WiMAX integrated access system is accomplished, and the result has verified that the Subscriber Station (SS) could access to the Internet via air interface.4) In this paper, we analyze the ARQ mechanism of WiMAX MAC layer, The result of the simulation is that under different radio channel conditions, the throughput of TCP application based on BE priority level is varied according to different ARQ parameters, and an improved scheme, which called Feedback-aware adaptive ARQ parameters for WiMAX (FAA-ARQ), is proposed, the simulation result based on NS2 shows that the scheme could improve the throughput of BE traffic.