An Energy Conservation Tracking System for the Device-free Target in Wireless Sensor Networks

In traditional active positioning schemes, the target has to holds assistant devices for being tracked; to liberate this limitation, a new positioning scheme, which is called passive tracking, has been recently introduced. In the passive tracking scheme based on received signal strength (RSS), the device-free target can be tracked by using radio frequency tomography (RFT) in the WSNs. In this paper, we present the RFT-based tracking scheme by estimating the crossing points (CP) on the line-of-sight links (LOSLs) between wireless nodes. Meanwhile, we analyze the power consumption of the RFT-based passive tracking scheme and propose an adaptive wireless web scheme, taking into account the tracking performance and power consumption. According to the results of simulations, without loss of generality, it is observed that the proposed scheme can provide excellent performance while owning the ability for energy saving.