Clock Synchronization for Wireless Positioning of COTS Mobile Nodes

The paper presents an innovative method to detect the position of commercial-off-the-shelf (COTS) wireless 802.1 la/b/g client hardware by evaluating differential signal propagation delays, thereby enhancing security or safety in wireless networks. The measurement is done by detecting the arrival time of a client signal at precisely synchronized access points. The overall vision is to accurately determine the position of a sender as a basis for new techniques for access control and system security as well as location based services in wireless environments. Safety-critical applications, like the task to make machines accepting commands only from operators located within the range of the machine, can be implemented. Furthermore, a security architecture can use such location information in order to offer services such as position based access policies, VLANs (Virtual Local Area Network), or Internet connections defining precise spatial coverage.