Study On Key Technologies Of EPON And WIMAX Convergence Network

In recent years, with the emerge and development of the high speed and strict quality requirement services, such as IPTV, HDTV, Online Games and P2P applications, the requirement for bandwidth grows rapidly. The operators become to focus on broadband access network building. The P2P traffic increases fast and it has used half and more network bandwidth. The coexistence of P2P services and C/S services becomes an important feature of the access network. 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, especially in long distance communication. So the convergence of fiber and wireless network becomes the development trend of access networks.As one of the most important broadband access networks, the traditional EPON does not support the direct communication between ONUs. When EPON carries P2P applications, network throughput will decrease rapidly and the switch burden in OLT is heavy. In this paper, a novel network architecture for the EPON and WIMAX convergence network is proposed. The proposed architecture provides flexible access and supports the directed communications between ONUs. Based on the novel architecture, the transmission mechanism, medium access control mechanism, protected switch architecture and mechanism and convergence solution are proposed. And an experimental system has been building to verify the feasibility and effectiveness of the proposed architecture. The main contributions of this thesis are as follows.1) A novel EPON architecture and a novel medium access control protocol which can realize direct packets transmission between ONUs are proposed. In the proposed EPON we adopt a novel circled architecture splitter which changed the transmission archtecure. The new transmission mechanism, medium access control mechanism, protected switch architecture and mechanism which match to the novel architecture are proposed too. In the novel EPON network, the throughput is increased by 50 percent, delay and switch burden in OLT decrease.2) A novel network reliability model (weighted reliability model) which is more suitable for passive optical networks (PON) is represented. The weighted reliability model reflects the amount of disruption caused by a failure by introducing a weighting factor. Based on the weighted reliability model, we analyze the reliability performance of PONs with representative topologies, protection types and ONU distribution scenarios. Because the access network is cost-sensitive, the parameter of cost/reliability is calculated to capture the trade-off between cost and reliability.3) Tow solutions for the integrated system of EPON and WiMAX are proposed: the solution of remote Digital RF signal architecture and of remote baseband signal architecture. Features and advantages of each architecture are analyzed. Based on the remote baseband signal architecture, two convergence bandwidth arbitration mechanisms are proposed and QoS performances are researched by the simulation system.4) The design of an EPON and WIMAX convergence network experimental system, which is called EPW system, is accomplished, and the PON motherboard which realized most system functions is established completely. The test on the EPW system verified that throughputof the novel EPON system is twice the traditional EPON in the limiting satiation, and the time of protected switch is less than 50ms.