Abstract

Delay tolerant networks (DTNs) are a class of networks that experience
frequent and long-duration partitions due to sparse distribution of
nodes.  The topological impairments experienced within a DTN pose
unique challenges for designing effective DTN routing protocols. For
an important class of DTNs nodes depend on their mobility to carry
message to the destination. Understanding mobility characteristics is
important for the design and analysis of such mobility-assisted routing
schemes, where node mobility is utilized to achieve message delivery.
In this work, we examine current routing methods and propose new
routing schemes. Further, we study the properties of common mobility
models and apply the results in the performance analysis of various
mobility-assisted routing schemes. Specifically, we analytically show
that inter-arrival times of mobile nodes can be closely approximated as
exponentially distributed under Random Waypoint and Random Direction
mobility models. We give analytical results for the inter-arrival rate and
the residence time when nodes come into contact. We show how such
results can be used in the analysis of various mobility-assisted routing
schemes by deriving analytical results for fundamental performance metrics
such as message delay, message delivery ratio, and buffer occupancy.
Through extensive simulation study, we show that our analytical results for
mobility characteristics and performance metrics are accurate.