Delay, Reliability and Trust in Mobile Ad Hoc Networks: A Space-Centric Approach to Routing

We establish a methodology for handling high mobility in wireless ad hoc networks. We present a novel design framework for the development of scalable ad hoc routing protocols that are capable of providing QoS guarantees (delay, reliability and trust) in the high-mobility regime. In the first part of this dissertation, we consider the problem of providing delay guarantees for ad hoc routing protocols under high mobility. The novel aspect of our work is the attribution of network and MAC layer congestion to space, which enables congestion-aware routing and provides delay guarantees over a much longer duration than that achieved by traditional ad hoc routing protocols. We prove that, over the duration during which the node density and the offered traffic pattern remain roughly constant, the spatial congestion of the network remains roughly invariant. We present an accurate method of spatial delay estimation, named "path integration," between distinct locations, and derive an upper bound for the estimation error. Furthermore, we develop a congestion-aware routing protocol to enable delay-optimized routing for real-time applications. Through extensive QualNet simulations, we perform a detailed evaluation of the presented framework in a realistic simulation set-up. The simulation studies demonstrate that the proposed scheme provides substantial improvements in the delivery of real-time applications such as Voice over IP (VoIP) for a wide range of node densities, velocities and offered traffic.;In the second part of this dissertation, we turn our attention to the problem of reliable and trustworthy routing in mobile ad hoc networks. We consider the implications of applying our spatial approach to improve routing reliability through difficult terrains with possibly untrustworthy regions in tactical mobile ad hoc networks. The proposed approach provides maps of spatial reliability and trust, that reflect the probabilities for finding trustworthy routes between distinct locations. We develop a routing protocol, named "Reliability Map Routing" (RMR), which discovers routes over spatial cells whose local reliability and trust metrics are distributed throughout the network via a fast dissemination algorithm. Furthermore, the RMR protocol is capable of reliable geocasting with low overhead. Via QualNet simulation studies, we compare the performance of the RMR protocol in terms of packet delivery ratio, delay, and overhead, and quantify the effects of node density, velocity, and traffic load on these performance metrics.