Title: An analytical study of fundamental mobility properties for encounter-based protocols

Authors: Thrasyvoulos Spyropoulos, Apoorva Jindal, Konstantinos Psounis

Addresses: Communication Systems Group, ETH, Zurich 8092, Switzerland. ' Department of Electrical Engineering, University of Southern California, Los Angeles, CA 90089 0791, USA. ' Department of Electrical Engineering, University of Southern California, Los Angeles, CA 90089 0791, USA

Abstract: Traditionally, mobility in ad hoc networks was considered as a necessary evil that hinders node communication. However, it has recently been recognised that mobility can be turned into a useful ally, by making nodes carry data between disconnected parts. Yet, this model of routing requires new theoretical tools to analyse its performance. A mobility-assisted or encounter-based protocol forwards data only when appropriate relays encounter each other. To be able to evaluate the performance of mobility-assisted routing schemes, it is necessary to know the statistics of various quantities related to node encounters. In this article, we present an analytical methodology to calculate a number of useful encounter-related statistics for a general class of mobility models. We apply our methodology to derive accurate closed form expressions for popular mobility models like Random Direction, as well as for a more sophisticated mobility model that better captures behaviours observed in real traces. Finally, we show how these results can be used to analyse the performance of mobility-assisted routing schemes or other processes based on node encounters. We demonstrate that derivative results concerning the delay of various routing schemes are very accurate under all mobility models examined.

Keywords: performance analysis; delay tolerant networks; DTN; hitting times; mobility; ad hoc networks; routing; encounter-based protocols.

DOI: 10.1504/IJAACS.2008.019198

International Journal of Autonomous and Adaptive Communications Systems, 2008 Vol.1 No.1, pp.4 - 40

Published online: 02 Jul 2008 *

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