The localization of the sensor nodes is a fundamental issue in the area of wireless
sensor networks (WSNs). An attractive way for estimating the location of mobile or
static wireless objects is by using the received signal strength (RSS) attenuation with the distance, which does not require any additional hardware. This is possible due to the fact that in most sensor nodes radios the received signal strength indicator (RSSI) is a standard feature and can be obtained automatically by the received messages. On the other hand the RSS is known for being noisy, unstable, variable and difficult to use in practice. For achieving a better understanding of the nature of these difficulties and limitations, and for identifying the range of applicability of the RSS in localization and tracking scenarios, a thorough study about the RSS and its dependence on the various factors and environmental conditions is essential.
The present doctoral dissertation investigates the feasibility of sensor node
localization and target tracking with the resources of the WSN technology, when using
only the RSS of the exchanged messages. Moreover, it offers experimental support to
the hypothesis that proper modeling of the RSS behavior and appropriate selection of
the topology parameters are essential for the applicability of WSN in real world
conditions. In brief, the present doctoral dissertation concerns with: (i) identifying the main factors that influence the accuracy, the variability and the reliability of the obtained RSS, (ii) modeling the RF signal propagation in the context of WSNs, and (iii)defining the basic deployment constraints and evaluation of the topology parameters that can guarantee successful localization and tracking.
For assessing the practical value of various RF-models, experiments using Tmote Sky and TelosB sensor nodes in real-field outdoor environment were carried out. The impact of a number of factors, such as the operating frequency of the radio, the transmitter–receiver distance, the variation of transceivers hardware due to manufacturing tolerances, the antenna orientation, and the environmental conditions, on the RSS was investigated. The influence of the various factors that affect the RF signal propagation and some constraints imposed by the WSN nature was accounted in order to design practical models, suitable for outdoor unobstructed and outdoor tree-obstructed environments.
A pre-deployment simulation framework has been introduced and in its context a
RF signal propagation-based connectivity strategy (RFCS) has been developed to fulfill
three deployment provisions: (i) discovering the most appropriate height from the
ground and distances for the sensor nodes, (ii) reducing the transmission power, and
(iii) minimizing the interference from non-neighbor nodes. The RFCS uses a RF signal
propagation model to predict the RSS in order to identify the most appropriate
communication-based deployment parameters, i.e. T-R distance, height from the ground and transmission power.
The localization and tracking considerations, by means of localization and tracking techniques, topology parameters and factors influencing the localization and tracking accuracy, are combined in illustrative simulation examples to evaluate their significance concerning the performance of the localization and tracking task.
Furthermore, the propagation model and the topology parameters being identified
were validated in real outdoor sensor node localization and target tracking tests. / -
| Identifer | oai:union.ndltd.org:upatras.gr/oai:nemertes:10889/5237 |
| Date | 14 May 2012 |
| Creators | Stoyanova, Tsenka |
| Contributors | Παπαδόπουλος, Γεώργιος, Παπαδόπουλος, Γεώργιος, Καλύβας, Γρηγόριος, Ευσταθίου, Κωνσταντίνος, Κουμπιάς, Σταύρος, Κωτσόπουλος, Σταύρος, Νικολετσέας, Σωτήρης, Κουλαμάς, Χρήστος |
| Source Sets | University of Patras |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | 0 |
| Relation | Η ΒΚΠ διαθέτει αντίτυπο της διατριβής σε έντυπη μορφή στο βιβλιοστάσιο διδακτορικών διατριβών που βρίσκεται στο ισόγειο του κτιρίου της. |
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