Space and time play a crucial role in wireless sensor networks, since sensor nodes are used to collaboratively monitor physical phenomena and their space-time properties. Wireless sensor networks (WSN) are envisioned to be used to fulfill complex monitoring tasks. A number of techniques and distributed algorithms for location estimation and time synchronization have been developed specifically for sensor networks. A similarity of time and space affects the location estimation and time synchronization, ranging from applications and requirements to basic approaches and concrete algorithmic techniques. An original approach for space and time localization in WSNs is given in this paper, also an energy-efficient approach is given, by clustering the WSNs. In both algorithms, we use only one mobile beacon for both localization and synchronization, a sensor node which moves around the sensor’s field, aware of its time and position, equipped with a GPS receiver. The synchronization component uses the packets required by the positioning component to improve its performance. The positioning component gets use from the communication, required by the synchronization component to decrease errors. A set of simulations are presented to evaluate the performance of our algorithms in order to reduce communication and processing resources and save energy and network resources.
wireless sensor networks space-time localization a mobile beacon GPS energy-efficiency