Wireless System with Secure Range Determination

Abstract

A wireless network may include devices that wirelessly transmit and receive packets. Each packet may include a preamble, a start-of-frame delimiter, a physical layer header, a sequence of symbols between the start-of-frame delimiter and the physical layer header, and a data payload. The sequence of symbols may have a pattern that is resistant to spoofing attacks. A receiving device may have a correlator that correlates known symbols against the symbols in the sequence using overlapping three-symbol-length correlation windows. Early arrival peaks in the output of the correlator may be used to correct time stamp information in the packets and late arrival peaks corresponding to spoofed signals from an attacker may be ignored. Time stamp information may be processed to determine ranges between transmitting and receiving devices.

Dependencies are inferred from the claim text.