Enlightness: An enhanced and lightweight algorithm for time-space localization in Wireless Sensor Networks

In wireless sensor networks (WSNs), detected events need to be localized in both time and space. As a result, sensor nodes need to have precisely synchronized clocks as well as to be localized in a common spatial reference system. While synchronization and localization algorithms have been proposed to solve these problems independently, in this paper we propose to combine both synchronization and localization into a single problem that we refer to as the time-space localization problem. We then propose the enlightness algorithm (enhanced and lightweight time and space localization), a new and enhanced time-space localization algorithm for wireless sensor networks. Our proposed algorithm, based on a previously proposed time-space localization algorithm called Lightness, uses mathematical ranking and weighting techniques to enhance the time computation process. We present an extensive set of experiments to evaluate the performance of our new algorithm. Our results indicate clearly that the proposed scheme can scale to thousands of nodes (over 2048) while reducing the synchronization error by half when compared to the original lightness algorithm. In comparison to the FTSP algorithm (flooding time synchronization protocol), a well known synchronization algorithm, our proposed enlightness algorithm is able to synchronize the clocks of the sensor nodes with a four times greater precision in small networks and about a 10 times greater precision in large networks.