A physical-layer technique to enhance authentication for mobile terminals

We propose an enhanced physical-layer authentication scheme for multi-carrier wireless systems, where transmission bursts consist of multiple frames. More specifically, it is based on the spatial variability characteristic of wireless channels, and able to work with moderate terminal mobility. For the authentication of the first frame in each data burst, the legal transmitter uses the saved channel response from the previous burst as the key for authentication of the first frame in the next burst. The key is obtained either via feedback from the receiver, or using the symmetric channel property of a TDD system. Then the authentication of the following frames in the burst is performed either by a Neyman-Pearson hypothesis test, or a least-squares adaptive channel estimator. Simulations in a typical indoor building show that the scheme based on the Neyman-Pearson test is more robust against terminal mobility, and is able to detect spoofing attacks efficiently with small system overhead when the terminal moves with a typical pedestrian speed.