Secure Spatial Signal Design for ISAC in a Cell-Free MIMO Network

Fuente: arXiv
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Main Authors: Rivetti, Steven, Bjornson, Emil, Skoglund, Mikael
Format: Preprint
Published: 2024
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author Rivetti, Steven
Bjornson, Emil
Skoglund, Mikael
author_facet Rivetti, Steven
Bjornson, Emil
Skoglund, Mikael
contents In this paper, we study a cell-free multiple-input multiple-output network equipped with integrated sensing and communication (ISAC) access points (APs). The distributed APs are used to jointly serve the communication needs of user equipments (UEs) while sensing a target, assumed to be an eavesdropper (Eve). To increase the system's robustness towards said Eve, we develop an ISAC waveform model that includes artificial noise (AN) aimed at degrading the Eve channel quality. The central processing unit receives the observations from each AP and calculates the optimal precoding and AN covariance matrices by solving a semi-definite relaxation of a constrained Cramer-Rao bound (CRB) minimization problem. Simulation results highlight an underlying trade-off between sensing and communication performances: in particular, the UEs signal-to-noise and interference ratio and the maximum Eve's signal to noise ratio are directly proportional to the CRB. Furthermore, the optimal AN covariance matrix is rank-1 and has a peak in the eve's direction, leading to a surprising inverse-proportionality between the UEs-Eve distance and optimal-CRB magnitude.
format Preprint
id arxiv_https___arxiv_org_abs_2401_12901
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Secure Spatial Signal Design for ISAC in a Cell-Free MIMO Network
Rivetti, Steven
Bjornson, Emil
Skoglund, Mikael
Information Theory
Signal Processing
In this paper, we study a cell-free multiple-input multiple-output network equipped with integrated sensing and communication (ISAC) access points (APs). The distributed APs are used to jointly serve the communication needs of user equipments (UEs) while sensing a target, assumed to be an eavesdropper (Eve). To increase the system's robustness towards said Eve, we develop an ISAC waveform model that includes artificial noise (AN) aimed at degrading the Eve channel quality. The central processing unit receives the observations from each AP and calculates the optimal precoding and AN covariance matrices by solving a semi-definite relaxation of a constrained Cramer-Rao bound (CRB) minimization problem. Simulation results highlight an underlying trade-off between sensing and communication performances: in particular, the UEs signal-to-noise and interference ratio and the maximum Eve's signal to noise ratio are directly proportional to the CRB. Furthermore, the optimal AN covariance matrix is rank-1 and has a peak in the eve's direction, leading to a surprising inverse-proportionality between the UEs-Eve distance and optimal-CRB magnitude.
title Secure Spatial Signal Design for ISAC in a Cell-Free MIMO Network
topic Information Theory
Signal Processing
url https://arxiv.org/abs/2401.12901