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The properties of high capacity microwave airborne ad hoc networks
thesisposted on 06.02.2017, 02:19 authored by Kopp, Carlo
This dissertation introduces the concept of the High Capacity Airborne Ad Hoc Network. Such an ad hoc mobile network is formed by interconnecting aircraft with high capacity directional microwave links. Electronically steered antennas and suitable antenna multiplexing and ad hoc routing protocols are employed to produce these links. The High Capacity Airborne Ad Hoc Network addresses the long standing difficulties extant in the provision of high capacity digital links to aircraft which are beyond the line of sight of the fixed ground based digital communications infrastructure. It also has the potential, when sufficient density of air traffic is available, to provide an alternative to established satellite communications for long and medium haul communications. The bounds on achievable signal to noise ratio and channel capacity performance for point to point links between aircraft in the troposphere and lower stratosphere are explored, using the comprehensive TROPPO propagation simulation algorithm developed for this purpose. Requirements and design constraints for active electronically steered antennas suitable for such applications are determined at a system and component level. A number of optimal antenna configurations are proposed, and antenna placement and tracking problems identified and resolved. The signal to noise ratio and channel capacity performance models are applied to empirical commercial air traffic position and altitude track datasets for the continental United States and North Atlantic and the behaviour of a wide area High Capacity Airborne Ad Hoc Network formed by linking this commercial air traffic is explored. The Etrack simulation algorithm was developed for this purpose and employed to simulate ad hoc network behaviour under a wide range of conditions and constraints. The properties of High Capacity Airborne Ad Hoc Networks are then explored to define constraints upon commercial and military applications of such a technology. Comparisons are made with existing LEO, MEO and GEO satellite communication schemes and extant airborne communication schemes. Finally, the behaviour of extant communications multiplexing and ad hoc routing strategies are explored in the context of a High Capacity Airborne Ad Hoc Network. The AQEM and DACR distributed multiplexing and routing protocols are proposed, respectively, as more suitable alternatives. This dissertation demonstrates that substantial connectivity and network capacity can exist between aircraft participating in an ad hoc network, under a range of weather conditions, traffic densities and traffic altitudes. Multiple hop connections spanning distances of several thousand kilometres, with link capacities of up to Gigabits/s are shown to be feasible, and to exhibit uninterrupted durations of hours. In summary it is shown that High Capacity Airborne Ad Hoc Networks are not only viable, but for many applications either competitive or superior to established LEO, MEO and GEO satellite communications, and extant airborne communication schemes.