Physical-Layer Authentication Enhancement via Random Watermark Hopping

Existing physical-layer authentication (PLA) schemes of tag superimposed on message signals (TSM) can achieve high authentication accuracy at the cost of increased latency and reduced communication performance. The schemes of tag superimposed on pilot signals (TSP) achieve desirable communication performance and low latency, but low randomness of the tag results in lower security. To further improve both security and communication performance, we propose a pseudo random watermark hopping-based PLA scheme in this article. The proposed scheme generates a pseudo-random sequence and designs a watermark hopping mechanism, which superimposes a carefully designed tag on the pilot or message signals accordingly. The proposed scheme enhances the security by utilizing the randomness from both tag generation and watermark hopping mechanism. Meanwhile, it decreases the authentication latency and improves the communication performance by superimposing the tag on the pilot signals without the message recovery process before authentication. The theoretical and experimental results demonstrate that the proposed scheme decreases the bit error rate (BER) and outage probability as well as increases the achievable rate of the system compared with the TSM scheme with the same key equivocation. Moreover, the security performance of our scheme is significantly improved compared with both TSM and TSP schemes.