Non-Consensus Crystal Oscillators Enhanced Radio Frequency Fingerprinting: State-of-The-Art

Consensus problem has been extensively studied in time synchronization for approaching non-consensus clocks to a common time frame. The non-consensus clocks driven by crystal oscillators, per se, are adequate features for device fingerprinting, however. A reflection of the non-consensus crystal oscillator in radio frequency (RF) is the carrier frequency offset (CFO), which has been put under the spotlight in the recent RF fingerprinting research. In this paper, we first investigate the relationship between crystal oscillator and CFO, with illustrating the application of CFO in achieving RF fingerprinting. We then conduct a review on the existing RF fingerprinting schemes leveraging CFO as a critical feature for identification. We also review the state-of-the-art schemes advocating CFO compensation for fingerprinting. Interestingly, two contradictory viewpoints on CFO both promote the research on RF fingerprinting in terms of such as identification accuracy.