DAPR (Distributed Adaptive Precomputed Restoration): An Algorithm for Assured Availability Directional RF and FSO MANET

Assuring network availability in directional RF and FSO (Free Space Optics) MANET Networks is fraught with challenges. These challenges stem mainly from the increased vulnerability of directional RF and FSO links to atmospheric effects, LOS blocking caused by geographic terrain, and increased difficulty in beam pointing and tracking owing to the narrow beam bandwidth. In this paper we propose a new Layer 1 restoration protocol called DAPR (Distributed Adaptive Precomputed Restoration). DAPR has innovative topology update and route update components which exhibit fast convergence under rapidly changing battlefield conditions, and guarantee up to three paths for all node pairs. It is expected that this Layer 1 protocol will be fast enough to be transparent to higher layers in all but the most extreme conditions, there by paving the way for high bandwidth any-any communications with guaranteed QoS, in directional MANETs. Preliminary simulation studies of DAPR have shown significant improvements in network availability.