Physical Layer Authentication for Two-User Two-Way Large-Scale Antennas Relay Systems

Relay communication is ubiquitous in various wireless communication networks, and physical layer security has grown to be an important issue for relay systems. This paper proposed an additively uniquely decomposable constellation pair (AUDCP) based physical layer authentication (PLA) scheme for two-user two-way relay systems. In the proposed scheme, tags generated by hash function are embedded into the messages at the two single-antenna users and a noncoherent detector is employed at the relay with large-scale antennas to execute signal detection in the multiple access phase, where the AUDCP design is used to guarantee the signal distinguishable. PLA is carried out at the relay to authenticate the identities of the users before the forwarding of received signals. Then, precoding is operated at the relay for the broadcasting phase with the estimated channel state information after a regenerated tag being embedded into the broadcasting signals. Finally, PLA is also implemented at the two users after the signal detection. Simulation results show that the proposed scheme achieves high reliability for secure relay communications.