The Shared Wdm-pon Media Access Control Methods

With the rapidly development of communication technologies, people are demanding for more and more network bandwidth. The communication network which has mainly served the voice become increasingly insufficient. As the technologies of the video chatting, online movie and other multimedia become popular with people, which urgent the provider to increase the bandwidth substantially. Now the present technology can basically meet the people's needs by increasing the bandwidth of backbone and local area networks, but the "last mile" access network becomes a bottleneck section.Passive Optical Network (PON) technology breaking down the traditional point to point communication method, with its low-cost, reliable and stable performance, the provision of transparent transmission capacity of broadband access network , become an effective solution. From the 20th century in 80 years to now, PON has experienced several stages of development as APON / BPON, EPON, GPON. However, the uplink direction of several access technologies have only a single channel, and all users share the bandwidth of the link capacity. With the development of services, which are heavy in bilateral, such as the video services ect, make the traditional access methods insufficient. If WDM technology will be applied to the PON network, it can make the uplink from a single into a number, and resolve the problem of uplink tight situation. Using what kind of media access control methods to make full use of upstream bandwidth has been a hot spots for studying.Here we firstly analyze the structure and working principle of sharing WDM-PON network. We proposed a simple bandwidth allocation algorithm, and then built the corresponding network in OPNET platform. Then study the influence of tuning time on the system performance, and present a match algorithm which use adjacent before and after time slots. Aiming to resolve the costly expense of networking issue, we use two fixed transmitters to replace the tunable transmitters, and verify its feasibility. Finally, we improve the simple algorithm, and make a comparesion between them.