Localized On-Demand Link State Routing for Fixed Wireless Networks

Fixed multihop wireless networks are gaining in popularity, due to their ease of deployment, for connecting rural communities and for providing broadband access to the Internet [3, 5]. In these networks, the locations of nodes are fixed, and therefore the set of potential neighbors (adjacencies) of a node that are within its transmission range is also static. On the other hand, the quality of a wireless channel between adjacent nodes varies frequently due to various factors such as external interference, channel fading, and inclement weather. This work focuses on reliable and scalable routing in such networks where node adjacencies are relatively static whereas link qualities are quite dynamic. Most of the wireless routing schemes have been designed primarily for mobile ad hoc networks with unpredictable topologies, and hence their route discovery and maintenance mechanisms are not ideal for fixed networks. Instead, linkstate-based hop-by-hop routing schemes are better suited for these networks, provided they do not require frequent flooding of link state updates. To make link state routing scale for ad hoc networks, limited dissemination based schemes have been proposed [4]. Fisheye state routing (FSR) [1] and hazy sighted link state (HSLS) [4] routing schemes update the nearby nodes at a higher frequency than the remote nodes that lie outside a certain scope. The drawback is that the chosen scope can be more than sufficient in some cases and less than necessary in other cases resulting in needless updates or forwarding loops. Our objective is to design a limited dissemination based routing scheme that ensures loop-free forwarding while notifying only those nodes that need to be informed of a link state change. We propose such an approach – localized on-demand link state (LOLS) – for scalable routing in fixed multihop wireless networks [2].