On channel-based user authentication for mobile terminals

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. 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. 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 residual testing. A binary hypothesis testing approach is formulated and illustrated via simulations.