SFPF: Spatio-Frequency Polarization Fingerprint for Anomalous Wireless Device Detection
SFPF fingerprinting detects swapped wireless hardware better than RF or single-direction polarization fingerprints.
The paper proposes a spatio-frequency polarization fingerprint (SFPF) to detect unauthorized replacement of wireless devices when communication, credentials, and logical identity stay unchanged. SFPF jointly captures complex polarization responses across frequencies and observation directions. Simulations improve normalized distance, Fisher score, and inter-/intra-class ratio over single-direction polarization fingerprints by 17.7%, 45.8%, and 11.3%. At 15–20 dB SNR, anomalous-device F1 is 87.3–90.4% and AUROC is 85.4–95.5%.
- Detects unauthorized radio hardware that keeps credentials and logical identity.
- Combines polarization responses over frequencies and viewing directions.
- Beats single-direction fingerprints by 17.7%, 45.8%, and 11.3% on three metrics.
- At 15–20 dB, F1 is 87.3–90.4% and AUROC is 85.4–95.5%.
Full article198 words · extracted from arxiv.org · click to collapse
Periodic inspection of deployed wireless devices is necessary because unauthorized hardware replacement may preserve communication functions, credentials, and logical identity, making anomalous devices difficult to detect. Such inspections are conducted under controlled measurement conditions to verify that each device remains consistent with its enrolled hardware state. Conventional radio-frequency fingerprint (RFF) may provide insufficient separation when replacement hardware closely resembles legitimate hardware, while a polarization fingerprint (PF) constructed at one observation direction may miss spatially nonuniform polarization changes. This paper proposes the spatio-frequency polarization fingerprint (SFPF), which jointly represents complex polarization responses over multiple frequencies and observation directions; conventional PF is its fixed-direction slice. We derive SFPF formation from hardware-dependent modal excitation, directional far-field radiation, and polarization projection. A first-order sensitivity analysis shows that the response to the same hardware change varies with both frequency and direction, motivating joint spatio-frequency acquisition. Electromagnetic simulations confirm the nonuniform spatio-frequency sensitivity and show that, under the same observation budget, SFPF improves normalized distance, Fisher score, and the inter-/intra-class ratio over PF by 17.7%, 45.8%, and 11.3%, respectively. Experiments show that SFPF consistently outperforms RFF and PF over 0--20~dB. At 15--20~dB, SFPF achieves anomalous-device F1 scores of 87.3--90.4% and AUROC values of 85.4--95.5%.
Text extracted automatically; images, tables and formatting may be missing. Original: https://arxiv.org/abs/2609.21873