Baras, Yu, Sadler issued patent for wireless communication authentication

Professor John Baras (ECE/ISR), his former student Paul Yu (EE Ph.D. 2008), and long-time collaborator Dr. Brian Sadler of the Army Research Laboratory were issued U.S. Patent 9,161,214 on Oct. 13, 2015.

The patent is for "Wireless communication method and system for transmission authentication at the physical layer." The invention is an authentication scheme encompassing a large family of authentication systems which may be built over existing transmission systems.

By superimposing a carefully designed secret modulation on the waveforms, authentication is added to the signal without requiring additional bandwidth. The authentication information (tag signal) is sent concurrently with data (message signal). The authentication is designed to be stealthy to the uninformed user, robust to interference, and secure for identity verification.

The tradeoffs between these three goals are identified and analyzed. The use of the authentication for channel estimation is also considered, and improved bit errors are demonstrated for time-varying channels. With a long enough authentication code word, an authentication system is achieved with very slight data degradation. Additionally, by treating the authentication tag as a sequence of pilot symbols, the data recovery may be improved by the aware receiver.

The three inventors also hold U.S. Patent 8,848,904 for "Method and implementation for information exchange using Markov models."

Published October 16, 2015