A Scheme of Private key Agreement Based on Delay Profiles in UWB Systems

Schemes of private key agreement based on channel characteristics have been proposed for countermeasure against eavesdropper in radio communication systems using carrier modulation. This paper proposes a new scheme of private key agreement for UWB system using impulse waves. Because it is generally difficult to apply the conventional schemes to UWB system where no carrier is used. The proposed scheme employs the differences of arrival time among the direct wave and the delayed waves, which are measured at both authorized radio stations changing the transmission and reception. The proposed scheme also employs the countermeasure for the detection error of the delayed waves which differ the arrival times at both radio stations. Computer simulations are carried out to evaluate the performance of the proposed scheme in wireless PAN environments. The results of the computer simulations show that the proposed scheme can achieve key agreement without errors at signal-to-noise ratio of about 22 dB.