Feature Issue on Optical Wireless Communications (OWC)
Weather conditions have a significant impact on availability of free-space optical (FSO) access networks. Under fair weather conditions, such networks can use long-range FSO links that span over 1 km. Under severe weather conditions, e.g., dense fog, only the short-range FSO links in the range of 200–400m remain operational. We propose an availability-differentiated networking scheme that supports two classes of service availability in an FSO network consisting of both long-range and short-range FSO links. Under severe weather conditions, the network topology is reconfigured to use only the short-range FSO links. Owing to the reduced network capacity in the reconfigured network, lower-availability services (LAS) will be preempted by higher-availability services (HAS). LAS and HAS have different revenue values. Given a set of hybrid LAS and HAS requests, we maximize the total revenue of LAS + HAS by selectively provisioning a portion of the service requests in the FSO access network. We formulate the problem into a common terminal multicommodity problem and develop an optimal algorithm to solve this problem in polynomial time.
© 2005 Optical Society of America