Study On Technologies Of Hybrid Passive Optical Networks

Passive optical network technology has become the emerging technology of broadband access areas, and hybrid TDM/WDM PON is a promising optical access network solution which taking advantages of both TDM-PON and WDM-PON. The research in this dissertation was supported by the National High Technology Research and Development Program of China (863 Program) project "Gigabits Ethernet Based on Passive Optical Networks", launched a system-depth theoretical and experimental study around the hybrid passive optical network technology. The main contributions of this paper are as the followings:(1) Based on the research of hybrid passive optical network architecture, a novel classification method is proposed that divided the Hybrid-PON into two catalog: Wavelength-Fixed type and Wavelength-Assignment type. The subdivision type of both catalogs are also proposed, and been discussed in detail.(2) A WDMA based Hybrid-PON system scheme (WDMA-EPON) is specified in this dissertation, which using wavelength division multiple access technology in the upsteam direction and broadcasting mechanism in the downsteam direction.The system architecture and key technologies are discussed in detail, and system model is built with OPNET Modeler.(3) The WDMA-EPON prototyping system is successfully developed by self-made low cost optical components/devices and efficient chip solution, which achieve the cost efficiency and high performance. The whole prototyping system includes central office equipment, customer premises equipment, embedded system control software and network management platform. Pilot network constructed by those prototype devices are normally running up and put through the system-level validation, the main function and performance are fully tested.(4) Two novel DBA algorithms LLR and LWR based on bandwidth debit and credit were proposed to solve the problem of unfair bandwidth allocation in EPON. The main idea is that the OUT can debit and credit the excessive bandwidth from those lightly loaded ONUs to highly loaded ONUs, and when in burst of traffic data the bandwidth of those credit ONUs can be reimbursed from those debit ONUs. The simulation results showed that these algorithms performed well in successful assurance of the brought bandwidth of ONUs in normal utilization, rather than penalties executed on all ONUs in former algorithms when there were some greedy ONUs. (5) In integration of EPON and Wireless Mesh Network (WMN), this dissertation illustrated an novel hybrid wireless passive optical network architecture (HWPON), and specified a genetic algorithm based placement method to solve the node planning problem of the hybrid network. In this method, it optimized the installation cost of the hybrid network system, with satisfaction of the requirement on maximum hop counts and whole wireless routers connection status.