A channel-based hypothesis testing approach to enhance user authentication in wireless networks

We consider a physical layer approach to enhance wireless security by using the unique wireless channel state information (CSI) of a legitimate user to authenticate subsequent transmissions from this user, thereby denying access to any spoofer whose CSI would significantly differ from that of the legitimate user by virtue of a different spatial location. In some existing approaches, multicarrier systems have been considered where the channel frequency response at distinct frequencies is used to devise a hypothesis testing approach: is the CSI of the current transmission (packet) the same as that of the previous transmission? In this paper we investigate a single-carrier time-domain approach via either residual testing or time-domain CSI comparison. A hypothesis testing approach is formulated to test whiteness of residuals from current transmission where the residuals are generated using the estimated channel from the previous transmission. We also consider a hypothesis testing approach where the time-domain CSI of the current transmission is compared with that of the previous transmission. Two binary hypothesis testing approaches are formulated and illustrated via simulations.