Channel-Like Fingerprinting Overlays for Authenticating OFDM Signals Using Channel Side Information

The authors present a method for overlaying Orthogonal Frequency Division Multiplexing (OFDM) transmissions with a fingerprint message at the physical-layer, where the fingerprint signal conveys a low capacity communication suitable for authenticating the transmission and further facilitating secure communications. A novel approach is discussed where previous Channel-State Information (CSI) is incorporated into the design of the fingerprint, allowing the signal to mimic distortions typical of time-varying channels. The fingerprint message is only visible to aware receivers who explicitly perform detection of the signal, but is invisible to receivers employing typical channel equalization.