RF Fingerprint detection in a wireless multipath channel

An RF Fingerprint is a unique signature passively imbued on a signal as it passes through a radio transmitter. We present the first RF Fingerprint detection technique capable of excellent performance in the presence of multipath propagation and the absence of a constant frequency offset. Our algorithm differs from previous work by performing joint channel estimation and classification on a steady state signal. The technique may be applied to any radio system with a repeated symbol sequence - such as a preamble. Our laboratory demonstrator is capable of distinguishing between the preamble signal transmitted by Universal Mobile Telephone System (UMTS) user equipment. We report excellent results - in excess of 99 % for 20 different UMTS models in an indoor wireless environment.