The Dynamic Bandwidth Allocation Algorithm In EPON

With the fast development of communication technology, the requests for bandwidth of users are increasing. EPON technology represents the convergence of mature Ethernet technology with PON and is regarded as the best candidate of next generation access network because of its low cost, broad bandwidth, being used and updated easily, simple maintenance and providing multi service.EPON is a point to multi point system. In the downstream direction, the optical line terminal broadcasts it's packets to all optical network units; in the upstream direction, multiple optical network units share the same transmission channel by using TDMA. In order to avoid conflict and acquire higher upstream bandwidth performance, it is very necessary to design a fair, high performance bandwidth allocation algorithm.Major in DBA, this paper introduces the current situation, foreground of the access network and advances of EPON, while summarizes the system architecture, work theory and key technology at first; in the next part, existing DBA algorithms: IPACT and CPFCT are introduced, while their virtue and weakness are analyzed. Based on the existing DBA algorithms, an improved DBA algorithm is proposed, while its performance is analyzed. It is shown from the simulation results that the new algorithm improves bandwidth utilization of uplink and ensures the Qos of different services and shows satisfied delay performance. At the same time, a novel algorithm based on game theory is proposed, which can attach pareto optimal nash equilibrium and realize the best performance of users and system. In the end, task of the paper,related conclusions and the expectation are summarized.