Autonomous reconfiguration and control in directional mobile ad hoc networks

Requirements for increasingly complex, scalable, and dynamic wireless networks, which provide assured end-to-end broadband connectivity in a wide range of scenarios, have been emerging. In this context, we have been investigating wireless technologies that provide extremely high data rates through the use of narrow-beam free space optical (FSO) and/or radio-frequency (RF) point-to-point links. The use of directional wireless communications to form flexible backbone networks, which provide broadband connectivity to capacity- limited wireless networks or hosts using omnidirectional transmission, promises to circumvent the scalability limitations of traditional flat wireless networks. We have been investigating backbones of base stations, in which topologies and mobility can be controlled for purposes of assured communications. We refer to these as Directional Mobile Ad Hoc Networks (DMANET). Our work considers the use of topology control to assure robust end-to-end broadband connectivity in heterogeneous and dynamic environments. Topology control is defined as the autonomous network capability to dynamically reconfigure its physical topology. In the case of directional wireless backbone (DWB) networks, the physical topology can be reconfigured through: Autonomous 1) Topology Reconfiguration (ATR): dynamic redirection of point-to-point links using heuristic algorithms for creating new topologies and pointing, acquisition and tracking of links. Topology reconfiguration algorithms, which compute minimum energy configurations by determining optimal link assignments between backbone nodes, are presented. The pointing, acquisition and tracking (PAT) process needed to physically redirect point-to-point links is also addressed. 2) Mobility Control (MC): dynamic reposition and "morphing" of backbone nodes. In this model, communication links define physical interactions between network nodes. Control mechanisms are designed to mimic physical systems' natural reaction to external excitations, which drive the network topology to minimum energy configurations Using both ATR and MC, networks are completely selforganizing. They can autonomously adapt their physical topology to maximize coverage to terminals or hosts while maintaining robust backbone connectivity. In this paper, we present the design, implementation and evaluation of our novel approaches to autonomous reconfiguration and control.