Topology characterization of high density airspace aeronautical ad hoc networks

Aeronautical ad hoc networks represent a special type of ad hoc wireless networks, given their significantly larger scale and the distinct characteristics of their mobile nodes. Aircraft populate the international airspace very heterogeneously. Some regions experience highly dense air traffic, with aircraft headings being largely uncorrelated. Other regions remain only very sparsely populated, with aircraft typically flying parallel to each other. Moreover, the number of airborne aircraft in a given region changes significantly throughout the day. In this paper, we focus on the densely populated European airspace, and investigate the topological behavior of multihop ad hoc wireless networks formed by air-air links of varying communications range. We derive analytical expressions for various topological aspects, such as the lifetime of inter-aircraft links, and the projected hop length using greedy forwarding. These results are in good agreement with the behavior observed in our simulations of the European air traffic scenario. In addition, we assess the performance of greedy forwarding in the aero-nautical environment and show that, under moderate connectivity, this technique delivers almost all packets to their destinations with a minimum hop count.