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چكيده انگليسي :

Designing a Reliable Scheme to Transport Data in WSNs Foad Farnia f farnia@ec iut ac ir July 5 2011 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Dr M R Hashemi hashemim@cc iut ac irAbstractWireless sensor networks are a novel generation of networks consisting of several sensors deployed across aspecified region These nodes communicate with each other in wireless manner Sensor nodes wereexpensive in earlier years but as result of growing wireless technology and decreasing cost of sensors suchnetworks are applied more and more nowadays These networks have been employed in many applicationareas and might extend to various other fileds also Nevertheless environment monitoring and target trackingare two major applications of these networks Having many areas of usage researchers have been focusingon problems and concerns of these networks lately To develop wireless sensor networks some challenges have to be resolved There s a challenging issue indesign of protocol stack layers specifically for these networks One of those layers is transport layer whichplays an important role in reliable end to end delivery over IP networks This role has a key functionality insome applications of wireless networks especially for those ones controlling and responding an eventhappening through network region They are called control and action applications sometimes In suchapplications data transmission from sensor nodes to base station sink is important Traditional solutions fortransport have not paid attention to event transport problem sufficiently that is to say transferringquantitative characteristics is not taken into account suitably This is a real necessity in some applications Delivering the information of an event is volnurable due to packet loss So in this thesis a transport schemeis proposed to transfer data from sensor nodes to sink called event to sink transport This scheme is based onclustering and divides the whole network into regions Each region has some special nodes called head nodein charge of aggregating and transmitting data packets to the sink On the other hand according to theapplication specific criteria the sink determines whether or not reliable transport is carried out If reliabilitydid not meet the sink tries to recover packets of the event These retries will be repeated until a specifiediteration reaches to a threshold and then the sink ignores more retrying Moreover since the design of thealgorithm is parametric one can change the variables flexibly Simulations were performed in OPNET tool version 14 5 and results showed that the proposed algorithm caneasily transport events from a region to the sink The results were compared with the case the transportalgorithm were not executed It means that the transport policy is the same but the loss recovery mechanismis omitted With the proposed algorithm the number of transmissions decreases and consequently the energyconsumption is decreased up to 20 Using this solution in more than usual rough environments however can achieve reliable transport with acceptable latency Keywords wireless sensor network reliable transport reliability event based

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