Uniquely-Factorable Constellation Pair Based Physical Layer Authentication for Cooperative Communications

In this paper, a uniquely-factorable constellation pair (UFCP) based physical layer authentication (PLA) mechanism is proposed to perform user authentication while trans-mitting message cooperatively. In the proposed mechanism, the user message and tag are modulated with the UFCP, and then the product signal of them is transmitted to the partner and the base station (BS) in the broadcast phase. In the forwarding phase, the users decode the received signals and forward them in the form of the Alamouti space-time coding. The BS utilizes the maximum likelihood detection to estimate the product signal, and then detect message and tag according to unique decomposability property. Finally, the PLA is completed by tag comparison. Simulation results show that the proposed mechanism has better authentication performance and security than the existing PLA.