Physical-Layer Authentication

TLDR

Authentication verifies identity, and while most mechanisms operate above the physical layer, some exist at the physical layer but incur bandwidth costs. This paper proposes a general analysis and design framework for physical‑layer authentication that transmits authentication information concurrently with data. By superimposing a carefully designed secret modulation onto waveforms, the authors add stealthy, interference‑robust, and secure authentication without extra bandwidth, and analyze the tradeoffs in block‑fading channels. The technique improves bit‑error rate in time‑varying channels through channel‑estimation use and simulation results show its potential application.

Abstract

Authentication is the process where claims of identity are verified. Most mechanisms of authentication (e.g., digital signatures and certificates) exist above the physical layer, though some (e.g., spread-spectrum communications) exist at the physical layer often with an additional cost in bandwidth. This paper introduces a general analysis and design framework for authentication at the physical layer where the authentication information is transmitted concurrently with the data. By superimposing a carefully designed secret modulation on the waveforms, authentication is added to the signal without requiring additional bandwidth, as do spread-spectrum methods. The authentication is designed to be stealthy to the uninformed user, robust to interference, and secure for identity verification. The tradeoffs between these three goals are identified and analyzed in block fading channels. The use of the authentication for channel estimation is also considered, and an improved bit-error rate is demonstrated for time-varying channels. Finally, simulation results are given that demonstrate the potential application of this authentication technique.