Distributed fiber optic sensor placement with shared protection
Aspects of the present disclosure describe distributed fiber optic sensor systems, methods, and structures that advantageously enable/provide for the proper placement/assignment of sensors in the DFOS network to provide for high reliability, fault tolerant operation that survives multiple fiber failures.
1. A method for distributed fiber optic sensing (DFOS) sensor placement with shared protection, the method comprising:
providing a DFOS network having a plurality of nodes optically connected by a plurality of optical links, said network defined by G(V, E), where V is a set of end nodes, and E is a set of optical fiber links that serve as sensor fibers and connect the set of end nodes V, and G is subject to a multiple link failure;
determining possible primary DFOS sensor assignments as primary_route_set;
determining all backup DFOS sensor assignments as backup_route_set; and
from the primary_route_set and the backup_route_set, selecting a minimum set that provides shared protection against the multiple link failure and provides sensor services without interruption during the multiple link failure;
wherein the primary_route_set comprises primary_routes and the backup_route_set comprises backup_routes, the backup_routes exhibiting a tree topology and each backup_route provides backup protection to a plurality of primary_routes; and
wherein any routes considered for inclusion into the primary_route_set and the backup_route_set are considered equally and the primary DFOS and backup DFOS sensor assignments are made as a one-step global optimization.
2. The method of claim 1 further comprising identifying, in the DFOS network, all possible fiber sensing routes constrained by a sensing range limit on each node as candidates for consideration for primary DFOS sensor assignment.
3. The method of claim 2 wherein all possible fiber sensing route trees in the DFOS network that are constrained by a sensing range limit on each node are considered as candidates for backup DFOS sensor assignment.
4. The method of claim 3 further wherein all primary DFOS candidates and backup DFOS are considered as candidates equally, applying a greedy algorithm, and selecting a minimum set of DFOS assignments from the primary candidates and the backup candidates such that each optical fiber link in the network is sensed at least once from two directions.
5. The method of claim 4 wherein for each individual optical fiber link that is shared by multiple primary_routes the number of backup_routes is greater than or equal to the number of sharing multiple primary_routes such that each primary_route has associated with it at least one backup_route when a single link failure occurs in the network.
6. The method of claim 5 wherein all primary_routes and backup_routes contain no loops and exhibit a distance that is less than a sensing range limit distance.
7. The method of claim 6 wherein backup_routes provide sensing functions from a direction opposite to that provided by primary_routes.
8. The method of claim 7 wherein the DFOS network provides Infrastructure as a Sensor (IaaS) services.
9. The method of claim 8 wherein the IaaS services provided include traffic and road condition monitoring.
10. The method of claim 1 wherein each optical link in the DFOS network is actively sensed via DFOS operation at least once from each direction.