Study On The Dynamic Bandwidth Allocation Algorithm Of EPON Upstream Channel

Optical access networks are becoming the dominative technology in access network space in coming years. Ethernet passive optical network (EPON), which represents the convergence of low-cost Ethernet equipment and low-cost fiber infrastructure, appear to be the most promising solution for the next-generation broadband access network.In this dissertation, some key technologies in EPON system are investigated, including study on system structure, MPCP protocol, and bandwidth allocation algorithm. The major achievements are outlined as follow:First, we introduce the evolution of EPON multiple access technology, study the theory architecture and key technologies of EPON in details, analyze the Multi-Point Control Protocol (MPCP) of IEEE802.3ah which is the basic of dynamic bandwidth allocation algorithm, and research the mechanism of REPORT/GATE as well as their flow chart.Then two classic DBA algorithms are reviewed. A new DBA algorithm, which is support the guarantee of QoS and based on fixed polling time, is the presented to efficiently and fairly allocate bandwidth among different users and different services. In order to satisfy the request of QoS, this new algorithms divide multiple services into three types and deposit them in different priority queues. Then poll different queues with different cycle time, transmit highest priority queue concentrative with fixed time slot, and transmit report frame before data frame to reduce idle time between polling cycle.Extensive simulation experiments are performed. Simulation results show that the new algorithm outperforms CPFCT algorithm in performances of utilization of bandwidth and delay.