Physical Layer Spectrum Usage Authentication in Cognitive Radio: Analysis and Implementation

Motivated by the primary user emulation attack in cognitive radios, this paper develops a physical layer user authentication scheme for wireless systems. The developed scheme consists of two stages: 1) one-way hash function for generating authentication tags and 2) physical layer tag embedding via controlled constellation perturbation. A detailed tradeoff analysis is provided that balances the performance of the user authentication for the secondary user and symbol detection for the primary user. In particular, we show that arbitrarily reliable user authentication can be achieved with an almost negligible performance degradation for the primary user under realistic system settings. Experimental results using the GNU Radio/Universal Software Radio Peripheral (USRP) platform are provided to validate the proposed scheme.