DSML: Dual signal metrics for localization in wireless sensor networks

In wireless sensor networks and wireless ad-hoc networks, localization systems have used diverse signal metrics such as Received Signal Strength Indicator (RSSI) and Time Difference of Arrival (TDoA) for accurate assignment of a node position. We propose a novel scheme that applies two signal metrics, which are TDoA and RSSI exclusively, into timebased positioning scheme (TPS). For energy-efficient coverage extension, the proposed scheme uses range check technique that reduces the communication energy consumption of nodes. With two location information of neighbor nodes, the node can calculate two candidate positions through bilateration. Without an additional beacon message reception, range check is applied to find the unique position between two candidate positions. Range check also can be carried out collaboratively in general environment with the information of two-hop neighbor nodes. At the performance evaluation, we analyze and test the reduced communication cost of nodes in the extended area. Also, it is shown that the ratio of unique position assignment is increased in the general environment by range check technique.