Date Added: Nov 2012
The Device-Free (DF) object tracking in wireless networks requires a tracked object neither be equipped with a transceiver nor actively participate in the tracking process. One of methods to implement a DF tracking system is to leverage the variation of radio signals introduced by object intrusion. However, many factors may result in the variation of radio signals and it is hard to distinguish which variation is caused by object intrusion. In this paper, the authors investigate how some factors impact signal variations, and in further impact the effectiveness of DF tracking. Based on analysis, they conduct experiments with TelosB motes, which are carried out in three representative environments with different system parameters.