no code implementations • 14 Mar 2024 • Hedieh Ajam, Vahid Jamali, Bernhard Schmauss, Robert Schober
The line-of-sight (LOS) requirement of free-space optical (FSO) systems can be relaxed by employing optical intelligent reflecting surfaces (IRSs).
no code implementations • 11 Mar 2024 • Moritz Garkisch, Sebastian Lotter, Gui Zhou, Vahid Jamali, Robert Schober
The proposed UT algorithm requires only a low overhead for direction and channel estimation and avoids outdated IRS phase shifts.
no code implementations • 8 Feb 2024 • Mohamadreza Delbari, Robin Neuder, Alejandro Jiménez-Sáez, Arash Asadi, Vahid Jamali
This leads to a considerable improvement in the achievable throughput for applications, where the length of the TDMA time intervals is comparable with the RIS reconfiguration time.
no code implementations • 16 Jan 2024 • Mohamadreza Delbari, George C. Alexandropoulos, Robert Schober, Vahid Jamali
In this chapter, we investigate the mathematical foundation of the modeling and design of reconfigurable intelligent surfaces (RIS) in both the far- and near-field regimes.
no code implementations • 19 Sep 2023 • Afifa Ishtiaq, Arash Asadi, Ladan Khaloopour, Waqar Ahmed, Vahid Jamali, Matthias Hollick
The high directionality of millimeter-wave (mmWave) communication systems has proven effective in reducing the attack surface against eavesdropping, thus improving the physical layer security.
1 code implementation • 1 May 2023 • Bile Peng, Karl-Ludwig Besser, Ramprasad Raghunath, Vahid Jamali, Eduard A. Jorswieck
Two major challenges of this problem are the high dimensionality due to the large number of RIS elements and the difficulty to obtain the full channel state information (CSI), which is assumed known in many algorithms proposed in the literature.
no code implementations • 17 Mar 2023 • Hedieh Ajam, Marzieh Najafi, Vahid Jamali, Robert Schober
We also consider the impact of linear, quadratic, and focusing phase shift profiles across the IRS on the power collected at the Rx lens for different IRS sizes.
no code implementations • 16 Nov 2022 • Moritz Garkisch, Vahid Jamali, Robert Schober
In this paper, we present a novel mobile user tracking (UT) scheme for codebook-based intelligent reflecting surface (IRS) aided millimeter wave (mmWave) systems.
no code implementations • 16 Oct 2022 • Vahid Jamali, Walid Ghanem, Robert Schober, H. Vincent Poor
The performance characterization of communication systems assisted by large reconfigurable intelligent surfaces (RISs) significantly depends on the adopted models for the underlying channels.
no code implementations • 14 Jun 2022 • Friedemann Laue, Vahid Jamali, Robert Schober
In order to study the impact of the phase-shift design on the device activity detection, we derive a generalized likelihood ratio test (GLRT) based detector and present an analytical expression for the probability of detection.
no code implementations • 5 May 2022 • Hedieh Ajam, Marzieh Najafi, Vahid Jamali, Robert Schober
The line-of-sight (LOS) requirement of free-space optical (FSO) systems can be relaxed by employing optical relays and optical intelligent reflecting surfaces (IRSs).
no code implementations • 31 Jul 2021 • Hedieh Ajam, Marzieh Najafi, Vahid Jamali, Bernhard Schmauss, Robert Schober
Our simulation results validate the accuracy of the proposed analytical channel model for IRS-assisted FSO systems and confirm that this model is applicable for both large and intermediate IRS-receiver lens distances.
no code implementations • 13 May 2021 • Vahid Jamali, Hedieh Ajam, Marzieh Najafi, Bernhard Schmauss, Robert Schober, H. Vincent Poor
Free-space optical (FSO) systems are able to offer the high data-rate, secure, and cost-efficient communication links required for applications such as wireless front- and backhauling for 5G and 6G communication networks.
no code implementations • 10 May 2021 • Friedemann Laue, Vahid Jamali, Robert Schober
This paper studies intelligent reflecting surface (IRS) assisted active device detection.
no code implementations • 6 Jan 2021 • Wayan Wicke, Harald Unterweger, Jens Kirchner, Lukas Brand, Arman Ahmadzadeh, Doaa Ahmed, Vahid Jamali, Christoph Alexiou, Georg Fischer, Robert Schober
The proposed CIR model is shown to consistently capture the experimentally observed distance-dependent impulse response peak heights and peak decays for transmission distances from 5cm to 40cm.
Emerging Technologies
no code implementations • 1 Oct 2020 • Hedieh Ajam, Marzieh Najafi, Vahid Jamali, Robert Schober
In this paper, we develop an analytical channel model for intelligent reflecting surface (IRS)-assisted free space optical (FSO) systems.
no code implementations • 5 Jun 2020 • Marzieh Najafi, Vahid Jamali, Robert Schober, Vincent H. Poor
Based on this model, one can design the phase shifts of the unit cells of a tile offline for the support of several transmission modes and then select the best mode online for a given channel realization.
no code implementations • 5 Feb 2020 • Vahid Jamali, Antonia Tulino, Jaime Llorca, Elza Erkip
Semi-supervised classification, one of the most prominent fields in machine learning, studies how to combine the statistical knowledge of the often abundant unlabeled data with the often limited labeled data in order to maximize overall classification accuracy.