  This paper presents small world in motion (SWIM), a new mobility model for
ad-hoc networking. SWIM is relatively simple, is easily tuned by setting just a
few parameters, and generates traces that look real--synthetic traces have the
same statistical properties of real traces. SWIM shows experimentally and
theoretically the presence of the power law and exponential decay dichotomy of
inter-contact time, and, most importantly, our experiments show that it can
predict very accurately the performance of forwarding protocols.
