Reseach On Algorithm Of DBA And Its Application In Economic GPON System

As the rapid development of network technology and the sharply fallen on the cost of optical fibe, the traditional low bandwidth copper access are being replaced by fiber to the home (FTTH) which has broadband and high-speed. Passive Optical Network (PON) with its low cost, simple structure and good performance is considered to be the best technology to achieve FTTH. Gigabit Passive Optical Network (GPON) as the next generation multi-service access network technology that support both Ethernet business also TDM business becomes the most favored operator access solution, with its high bandwidth utilization, high-speed and high efficiency, full-service Quality of Service (QoS) guaranteed. Dynamic bandwidth allocation (DBA), as one of the most critical technologies, has a decisive influence for the success of GPON. Therefore developed a simple and practical DBA algorithm becomes significant.Firstly, this thesis analyzes the background and significance of the study, introduces the current situation and dynamic research at home and abroad, followed by a discussion of the structure of GPON system, working principle and key technologies. Analyzes its layered protocol, frame structure and the unique GEM package model in GPON. Then, elaborates the relationships among transport container (T-CONT) and business types, and bandwidth types. Thirdly, introduces three dynamic bandwidth reporting mechanisms to explain the working principle of the DBA. Fourthly, expounds the economic GPON system requirements, the main features and software architecture, introduces its module division and core module design, elaborates the DBA module design.This thesis analyzes several existing DBA algorithm to compare their advantages and disadvantages, combining economic situation presents a simple and feasible GPON DBA algorithm. In this algorithm, the different types of T-CONTs are divided into several templates, and allocated bandwidth by templates in a single cycle. The algorithm considers different business demanding for bandwidth in details, cycle selection, ranging windows process and its impact on the business. And also provides the method of TDM compensation bandwidth interrupted by ranging. It is simple, efficient and meet the granularity which GPON series of proposed requirements in bandwidth allocation, so that balance the fairness of business, QoS and bandwidth utilization. Finally, realizes the ideas and processes of the algorithm, and implements in the economy GPON system.