Propagation Modeling for Radio Frequency Tomography in Wireless Networks

Non-cooperative localization is an important class of applications with the goal of detecting and tracking objects without their explicit participation. Recognizing that these objects will attenuate any radio signals that pass through them, recent works have proposed using the received signal strength (RSS) measurements from networks of portable wireless devices to detect, localize, and track objects through radio frequency (RF) tomography. Because the effects of these objects on radio signals can be relatively small, accurate radio propagation models are essential to the accuracy and reliability of these methods. Despite their critical importance, only limited work has been done to develop and test such models. In this paper, we describe the RF tomography problem in detail, comparing both existing and novel shadowing models analytically. We design an RF tomography testbed and describe the techniques used to conduct field test measurements. We present the experimental results from our RF tomography testbed comparing several different shadowing models. Further, we present the results of applying the different shadowing models to RSS measurements obtained in a field test and evaluate how well each model approximates the radio propagation experienced during our test.