Physical Layer Security with Frequency-Hopping and Finite-Alphabet Inputs
Year: 2026
Type: conference-paper
Abstract: This paper investigates the physical layer security of frequency-hopping (FH) transmission schemes when the hopping sequence is publicly known. We consider a single-antenna transmitter communicating with a legitimate receiver over a channel estimated with a known error distribution, in the presence of a passive eavesdropper whose channel statistics are available at the transmitter. We show that, when the number of hopping frequencies is sufficiently large, the instantaneous channel fluctuations induced by FH transmissions can be effectively averaged out, and the secrecy performance is accurately predicted by the ergodic secrecy rate (ESR). The ESR is maximized by selecting the optimal modulation order from a set of admissible finite constellations. We derive a closed-form condition on the optimal modulation order, which only depends on the tail probabilities of the legitimate and eavesdropper signal-to-noise ratio (SNR) distributions, and we propose an efficient algorithm for its computation. In particular, we demonstrate that a positive secrecy rate can be achieved even when the eavesdropper has a higher average SNR than the legitimate receiver, provided that the spread of the eavesdropper SNR distribution is sufficiently large. Numerical results validate the proposed framework under a variety of channel models.
Source: HAL
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7204677804