Development of an Algorithm for Fiber-to-the-Home Passive Optical Network Automatic Self-restoration Scheme Using Access Control System

Problem statement: Cables that are installed outdoors are subjected to harsh environmental conditions which make break down inevitable. When this happen it will disrupt the services and cause trouble to the users. To overcome this is to provide a means of restoring the network in case of failure. We introduced the Access Control System (ACS) and Customer Access Protection Unit (CAPU) to provide FTTH-PON monitoring, fault detection and protection. Approach: To design the C programs for ACS and CAPU, we will come up with the algorithms which describe the switching configuration in general. The switching configurations are tabulated in truth tables and flow charts are constructed. Based on the flow charts, the respective C programs for ACS and CAPU will be written. The C programs will then be tested through simulation. After successful simulations, the programs will be downloaded into the respective PIC microcontrollers in the ACS and CAPU for lab testing. Results: When several faults occur at various lines, each Multi Access Detection System (MADS) informs ACS and all CAPUs of the current line conditions. As programmed, ACS and CAPU will configure their switches to restore the network. When one of the working lines fail, the optical signal will be routed to its dedicated protection line. But when both its working and protection line fail, the optical signal will be routed to its neighboring protection line. Conclusion: We have successfully simulated the restoration of the optical signal when fault occur at its working line by restoring it to its dedicated protection line.