Studies On Protection Mechanisms For Passive Optical Networks

The passive optical network (PON) is considered to be the mostattractive broadband access technology for its high capacity, low cost andeasy maintenance. As the access speed continues to grow up, the systemsurvivability together with protection and restoration mechanism of PONsupporting high-speed transmission has become a critical issue. Traditionalprotection idea is to introduce redundancy by duplicating network resources,so as to provide alternate links when failure occurs to remain connected.However, massive link duplication is definitely to bring up the system capitalexpenditure, which is unaffordable for the cost-sensitive PON systems. Thisthesis is a study on the protection mechanism for PON, and proposes twolow-cost self-protected schemes, with the system architectures and protectionprocesses designed.A ring-type collaborative protection scheme on the user side is proposed.The scheme connects the users with protection fibers into protection groupsto get collaborative protection, and by this means shortens the protectionfiber length to control the system cost. The remote node structure andwavelength assignment plan are designed, and overall network architectureand specific protection principles are presented. By using wavelengthre-modulation, bidirectional transmission on single wavelength in the samefiber can be achieved, and is experimentally demonstrated at10Gb/s. Thescheme can protect the entire optical networks, and by the availability andcost calculation and comparison, protection performance is analyzed.A wireless collaborative protection scheme is proposed, using wirelesssignals to carry protection data and wireless links instead of traditionalbackup fibers as protection links. By establishing wireless connectionsbetween two neighboring users, the scheme can realize mutual protection, andreduce fiber laying, thus lower system cost. The network architecture and data transmission method are designed, and system operating principles andprotection switching processes are presented. Multi-user system simulation iscompleted to obtain transmission performance, and the feasibility of theproposal is verified.