Geometric Constraint-Based Range-Free Localization Scheme for Wireless Sensor Networks

Localization is one of the most challenging issues in wireless sensor networks. It is broadly classified into range-based and range-free. The range-based schemes are generally expensive, and require additional range determining hardware. Besides, the range free schemes are simple, inexpensive, and energy efficient, where the localization is performed using proximity information. In this paper, we have proposed an analytical geometry-based range-free localization scheme, where a mobile beacon is used as a reference node. The proposed scheme uses three non-collinear beacon points to derive the analytical geometry of an arc. For localization, the arc parameters are used to generate the chords on the virtual circle of the sensor node. Later, the perpendicular bisector of the chord and approximated radius are used to localize the sensor node. The accuracy of localization depends on the size of the constraint area, which is used for the approximation of the arc parameters. To provide better localization accuracy, we have used an adaptive mechanism that defines the approximation accuracy of the arc parameters at different sizes of the constraint area. The simulation and experimental validation show that the proposed scheme provides better localization accuracy than the existing range free localization schemes.