Worst-case latency of broadcast in intermittently connected networks

Abstract

Worst-case latency is an important characteristic of information dissemination protocols. However, in sparse mobile ad hoc networks where end-to-end connectivity cannot be achieved and store-carry-forward algorithms are needed, such worst-case analyses have not been possible to perform on real mobility traces due to lack of suitable models. We propose a new metric called delay expansion that reflects connectivity and reachability properties of intermittently connected networks. Using the delay expansion, we show how bounds on worst-case latency can be derived for a general class of broadcast protocols and a wide range of real mobility patterns. The paper includes theoretical results that show how worst-case latency can be related with delay expansion for a given mobility scenario, as well as simulations to validate the theoretical model.

Imperfect Knowledge in Autonomous Urban Traffic Manoeuvres

“…For realistic worst case time bounds in real-time broadcast communication, we e.g. refer to the work of Asplund et al [4].…”

Modelling Correlated Mobility

“…The novelty of our approach is to use properties of the colouring process as an abstract representation of mobility. Intuitively this abstract representation captures the rate at which message dissemination could take place in the network which is also closely related to dynamic graph expansion [5].…”

“…Lack of Expansion. The second prominent effect is what we choose to call lack of expansion (motivated by the close connection to expander graphs [5]). This means that the rate of the colouring process seems not to correspond to the number of coloured nodes.…”

“…Many of these approaches are based on or inspired by epidemiological models [15]. We have previously characterised the worst-case latency of broadcast for such networks using expander graph techniques [5]. In a preliminary version of this paper we developed the basic framework for deriving the latency of ideal epidemic routing [4].…”