Hindawi Publishing Corporation
International Journal of Distributed Sensor Networks
Volume , Article ID , pages
http://dx.doi.org/.//
Research Article
The DTN Routing Algorithm Based on Markov Meeting Time
Span Prediction Model
En Wang,
1
Yongjian Yang,
1
Bing Jia,
1
and Tingting Guo
2
1
Department of Computer Science and Technology, Jilin University, Changchun 130012, China
2
Department of Soware Engineering, Jilin University, Changchun 130012, China
Correspondence should be addressed to Yongjian Yang; yyj@jlu.edu.cn
Received July ; Accepted August
Academic Editor: Yuan He
Copyright © En Wang et al. is is an open access article distributed under the Creative Commons Attribution License, which
permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Putting forward an ecient routing algorithm in DTN (delay tolerant network) has become a focus of attention due to the existing
phenomena that the connections between nodes in the network change dramatically over time and the communications suer from
frequent disruptions. In this paper, the meeting time span between nodes is predicted using the Markov model, and the relay node
holding the shortest meeting time span with the destination node is determined as the most ecient node. In the two phases, spray
phase and wait phase, the message is routed according to the utility value. us, the routing algorithm based on Markov meeting
time span prediction model is provided. Simulation results suggest that this algorithm eciently improves the delivery rate and
reduces the average delay.
1. Introduction
DTN (delay tolerant network) []whichisputforwardby
Fall at the international committee SIGCOMM in []
is a kind of challenged network characterized by changing
topology and lacking of stable links between terminates. End-
to-end transmission latency may be arbitrarily long due to
occasionally connected links [, ].
Examples of DTN are those operating in mobile or
extreme scenarios such as interplanetary networks [, ],
military networks [], rural area networks [], wildlife track-
ing sensor networks [, ], and pocket switched networks
(PSNs) [, ]. Developing ecient routing protocols in this
kind of network where topology changes dramatically has
been a hot issue.
Generally, present routing protocols in DTN can be
classied into two categories: copy-based routing []and
eciency-based routing []. Epidemic []isthebasiccopy-
based routing protocol that exchanges messages in a simple
way which seems like epidemic. Considering that the number
of copies during its execution is out of control, this method
will cost a lot of network resources: rubbish copies increase
with the growth of time and nally lead to congestion.
To control the number of message copies, there comes a
classical routing protocol based on quota: spray and wait [,
]. Several improvements have been made on it aerwards.
Multiperiod spraying [] extends the single spray phase into
several spray phases, expecting ecient usage of network
resources by infecting more nodes. Spray and focus []
improves the wait phase. e message is routed through
thenodeofthehighestutility.Sprayandforward[]
also improves the wait phase and calculates the meeting
probability using the Markov location model. However, all
the above methods only focus the improvements on one of
the two phases, and spray and forward only considers the
meeting possibility []ataspecicplacewithoutconsidering
the possible meeting on the way. To make up the above
drawbacks, we propose a new DTN routing algorithm based
on the Markov [] meeting time span prediction model: pre-
dict and forward (PAF). e meeting time span is predicted
using the Markov model, and the message is forwarded to
the node of the highest utility. Experiments show that this