On Secrecy Capacity of Binary Beampointing Channels with Block Memory and Feedback

Fuente: arXiv
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Main Authors: Li, Siyao, Chen, Mingzhe, Li, Shuangyang, Caire, Giuseppe
Format: Preprint
Published: 2025
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author Li, Siyao
Chen, Mingzhe
Li, Shuangyang
Caire, Giuseppe
author_facet Li, Siyao
Chen, Mingzhe
Li, Shuangyang
Caire, Giuseppe
contents This paper investigates the secrecy capacity of the binary beampointing (BBP) channel with block memory and feedback, a simplified yet insightful model for millimeter-wave (mmWave) systems with beamformed transmissions and backscatter feedback. We consider a system where a legitimate receiver and a passive eavesdropper experience independent and uniformly distributed angular directions over transmission blocks, with the base station receiving noiseless, unit-delayed feedback from both, under the per-symbol input cost constraints. We establish a closed-form upper bound on the secrecy capacity, which is based on the main channel between the base station and the legitimate receiver. Moreover, we propose a joint communication and adaptive sensing (JCAS) scheme and derive its achievable secrecy rate. Simulation results show that the gap between the inner and outer bounds narrows as the number of block length increases. This reveals the efficiency of this JCAS scheme, which strategically leverages feedback to balance the demands of sensing the legitimate user and preventing information leakage to the eavesdropper.
format Preprint
id arxiv_https___arxiv_org_abs_2508_20980
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On Secrecy Capacity of Binary Beampointing Channels with Block Memory and Feedback
Li, Siyao
Chen, Mingzhe
Li, Shuangyang
Caire, Giuseppe
Information Theory
This paper investigates the secrecy capacity of the binary beampointing (BBP) channel with block memory and feedback, a simplified yet insightful model for millimeter-wave (mmWave) systems with beamformed transmissions and backscatter feedback. We consider a system where a legitimate receiver and a passive eavesdropper experience independent and uniformly distributed angular directions over transmission blocks, with the base station receiving noiseless, unit-delayed feedback from both, under the per-symbol input cost constraints. We establish a closed-form upper bound on the secrecy capacity, which is based on the main channel between the base station and the legitimate receiver. Moreover, we propose a joint communication and adaptive sensing (JCAS) scheme and derive its achievable secrecy rate. Simulation results show that the gap between the inner and outer bounds narrows as the number of block length increases. This reveals the efficiency of this JCAS scheme, which strategically leverages feedback to balance the demands of sensing the legitimate user and preventing information leakage to the eavesdropper.
title On Secrecy Capacity of Binary Beampointing Channels with Block Memory and Feedback
topic Information Theory
url https://arxiv.org/abs/2508.20980