Onur Cagirici | Searcharxiv

arXiv2016

Avoiding the Flip Ambiguities in 2D Wireless Sensor Localization by Using Unit Disk Graph Property

In this paper, we propose a range-based localization algorithm to localize a wireless sensor network (WSN) in 2D. A widely used algorithm to localize a WSN in 2D is trilateration, which runs in polynomial time. Trilateration uses three distance measurements to localize a node. In some cases, the lack of connectivity leads to a low percentage of localized nodes since a node's position can be fixed using three distance measurements. We propose an algorithm that finds the position of a node by using the absence of a distance measurement in addition to a third distance measurement. If two nodes are not able to sense each other, that means the distance between them is more than the sensing range. Therefore, our algorithm checks if the possible positions of an unlocalized node $u$ is inside the sensing range of a localized node $\ell$ that is not the neighbor of $u$. In such case, we eliminate one of the possible positions.

cs.NI↗

arXiv2015

Exploiting Coplanar Clusters to Enhance 3D Localization in Wireless Sensor Networks

This thesis studies range-based WSN localization problem in 3D environments that induce coplanarity. In most real-world applications, even though the environment is 3D, the grounded sensor nodes are usually deployed on 2D planar surfaces. Examples of these surfaces include structures seen in both indoor (e.g. floors, doors, walls, tables etc.) and outdoor (e.g. mountains, valleys, hills etc.) environments. In such environments, sensor nodes typically appear as coplanar node clusters. We refer to this type of a deployment as a planar deployment. When there is a planar deployment, the coplanarity causes difficulties to the traditional range-based multilateration algorithms because a node cannot be unambiguously localized if the distance measurements to that node are from coplanar nodes. Thus, many already localized groups of nodes are rendered ineffective in the process just because they are coplanar. We, therefore propose an algorithm called Coplanarity Based Localization (CBL) that can be used as an extension of any localization algorithm to avoid most flips caused by coplanarity. CBL first performs a 2D localization among the nodes that are clustered on the same surface, and then finds the positions of these clusters in 3D. We have carried out experiments using trilateration for 2D localization, and quadrilateration for 3D localization, and experimentally verified that exploiting the clustering information leads to a more precise localization than mere quadrilateration. We also propose a heuristic to extract the clustering information in case it is not available, which is yet to be improved in the future.

cs.NI↗