AoA-Based Physical Layer Authentication in Analog Arrays under Impersonation Attacks

Abstract--We discuss the use of angle of arrival (AoA) as an authentication measure in analog array multiple-input multipleoutput (MIMO) systems. A base station equipped with an analog array authenticates users based on the AoA estimated from certified pilot transmissions, while active attackers manipulate their transmitted signals to mount impersonation attacks. Our results show that some attack techniques with knowledge of the combiners at the verifier are effective in falsifying the AoA and compromising the security of the considered type of physical layer authentication. Physical layer authentication (PLA) is gaining momentum in the realm of wireless communication systems due to its ability to be deployed relatively easily in device-to-device setups without the need for a cumbersome public key infrastructure [1]. Unlike conventional cryptographic methods, PLA authenticates devices or users based on unique signal characteristics observed at the physical layer.