Research On Protection Strategy For Cascaded Passive Optical Networks

Access Network is one of the most important infrastructures in the communication networkwhile Optical Access Network has become a primary solution for broadband access. PassiveOptical Network (PON) has been widely accepted as a major solution for FTTH in the future dueto its simple maintenance, high reliability and low cost characters, etc. With the rapid growth ofInternet services and bandwidth requirements, traditional single-stage PON has already showedembarrassment to meet the rapidly increasing user demand as well as the varieties of userdistribution. Cascaded PON with several splitters cascaded together can not only provide largenumber of access users simultaneously with low cost, but also easy for expansion and upgradingof the network system. These advantages have made it a research and development hot spotcurrently. This thesis presents a comprehensive study on the protection mechanism for CascadedPON by using theoretical analysis and numerical simulations.Firstly, the thesis introduces the principles of PON system and its major technologies.Followed are the analysis and discussions about the reliability performance and existing protectionmechanisms of single-stage PON. For different applications of Cascaded PON, the thesis givesreliability models for two-stage PON including star and bus topology. Some protection schemes areproposed followed with the reliability and cost analysis. Theoretical research and numericalcalculation shows that the reliability performance of the improved protection schemes for both ofthe Cascaded PON structures has been significantly improved. Finally, the thesis analyses theapplication requirements of Cascaded PON system and proposes appropriate protectionmechanisms for different application scenes.