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Rafael F. Schaefer

11 accepted papers

2024

Nonasymptotic Performance Limits of Low-Latency Secure Integrated Sensing and Communication Systems

ICASSP 2024accepted

This paper considers an information theoretic model for secure integrated sensing and communication (ISAC) with the goal of establishing fundamental limits in low-latency scenarios. In this secure ISAC model, a message is transmitted through a state-dependent wiretap channel with decoder-side state…

Cited by 0SourceScholar
2021

Communication Over Block Fading Channels - An Algorithmic Perspective On Optimal Transmission Schemes

ICASSP 2021accepted

Wireless channels are considered that change over time but remain constant for a certain (coherence) period. This behavior is perfectly captured by block fading channels and affects the performance of the corresponding wireless communication systems. Desired closed-form characterizations of optimal…

Cited by 0SourceScholar
2021

Federated Learning with Local Differential Privacy: Trade-Offs Between Privacy, Utility, and Communication

ICASSP 2021accepted

Federated learning (FL) allows to train a massive amount of data privately due to its decentralized structure. Stochastic gradient descent (SGD) is commonly used for FL due to its good empirical performance, but sensitive user information can still be inferred from weight updates shared during FL it…

Cited by 0SourceScholar
2021

Real Number Signal Processing can Detect Denial-of-Service Attacks

ICASSP 2021accepted

Wireless communication systems are inherently vulnerable to adversarial attacks since malevolent jammers might jam and disrupt the legitimate transmission intentionally. Of particular interest are so- called denial-of-service (DoS) attacks in which the jammer is able to completely disrupt the commun…

Cited by 0SourceScholar
2020

Hybrid Precoding for Secure Transmission in Reflect-Array-Assisted Massive MIMO Systems

ICASSP 2020accepted

Recently, a hybrid analog-digital architecture has been proposed for multiuser MIMO transmission in the millimeter-wave spectrum using reflect-arrays. The architecture exhibits scalability and high energy-efficiency while keeping the transmitter cost-efficient. Inspired by this architecture, we desi…

Cited by 0SourceScholar
2020

Robust Transmission Over Channels with Channel Uncertainty: an Algorithmic Perspective

ICASSP 2020accepted

The availability and quality of channel state information heavily influences the performance of wireless communication systems. For perfect channel knowledge, optimal signal processing and coding schemes are well studied and often closed-form solutions are known. On the other hand, the case of imper…

Cited by 0SourceScholar
2019

Detectability of Denial-of-service Attacks on Communication Systems

ICASSP 2019accepted

Wireless communication systems are inherently vulnerable to adversarial attacks since malevolent jammers might jam and disrupt the legitimate transmission intentionally. Accordingly it is of crucial interest for the legitimate users to detect such adversarial attacks. This paper develops a detection…

Cited by 0SourceScholar
2019

On the Computability of the Secret Key Capacity under Rate Constraints

ICASSP 2019accepted

Secret key generation refers to the problem of generating a common secret key without revealing any information about it to an eaves-dropper. All users observe correlated components of a common source and can further use a rate-limited public channel for discussion which is open to eavesdroppers. Th…

Cited by 0SourceScholar
2018

Secrecy Capacity Under List Decoding For A Channel with A Passive Eavesdropper and an Active Jammer

ICASSP 2018accepted

We investigate secure communication over a channel that undergoes two different classes of attacks at the same time: passive eavesdropping and active jamming. This scenario is perfectly modeled by the concept of arbitrarily varying wiretap channels (AVWCs). We derive a full characterization of the s…

Cited by 0SourceScholar
2016

Degradedness and stochastic orders of fast fading Gaussian broadcast channels with statistical channel state information at the transmitter

ICASSP 2016accepted

The capacity regions of Gaussian broadcast channels depends on the knowledge of channel state information (CSI). When there is only statistical CSI at the transmitter and full CSI at the receiver, the ergodic capacity region is unknown in general. In this paper we investigate the relation between th…

Cited by 0SourceScholar