7 citations · 8 across the 15 of their papers we have counts for
18 papers
Simultaneous Direct and Indirect Channel Estimation for RIS-Assisted MIMO Communications
Daniel V. C. de Oliveira, Daniel C. Alcantara, Fazal. E Asim +2
This paper introduces an enhanced channel estimation method for reconfigurable intelligent surface (RIS)-assisted multiple-input multiple-output (MIMO) communications. Considering…
Q-SPARSE: Quantum Subspace Projection for Near-Field Angle-Range Spectrum Estimation
Mostafizur Rahaman Laskar, Sajad Daei, Gabor Fodor +1
Near-field wavefront curvature enables joint angle-range localization, but exploiting it entails repeated covariance-eigenspace tests over a two-dimensional spherical manifold. We…
A Mathematical Theory of Near-Field Super-Resolution
Sajad Daei, Gabor Fodor, Mikael Skoglund
Finite-aperture near-field sensing leads to a super-resolution geometry fundamentally different from the translation-invariant Fourier setting. In the Fresnel regime, wavefront cur…
Rethinking Channel Charting: A Graph Perspective
Yifei Jin, Yuxin Zhao, Dandan Hao +1
Channel charting is a self-supervised framework that learns low-dimensional spatial representations from high-dimensional channel state information. We revisit channel charting fro…
Convexity Meets Curvature: Lifted Near-Field Super-Resolution
Sajad Daei, Gábor Fodor, Mikael Skoglund
Extra-large apertures, high carrier frequencies, and integrated sensing and communications (ISAC) are pushing array processing into the Fresnel region, where spherical wavefronts i…
On the Impact of Channel Aging and Doppler-Affected Clutter on OFDM ISAC Systems
Steven Rivetti, Gabor Fodor, Emil Björnson +1
The temporal evolution of the propagation environment plays a central role in integrated sensing and communication (ISAC) systems. A slow-time evolution manifests as channel aging…
Semi-Blind Joint Channel and Symbol Estimation for Beyond Diagonal Reconfigurable Surfaces
Gilderlan Tavares de Araújo, André L. F. de Almeida, Buno Sokal +1
The beyond-diagonal reconfigurable intelligent surface (BD-RIS) is a recent architecture in which scattering elements are interconnected to enhance the degrees of freedom for wave…
Beamforming Saturation in Two-Timescale RIS-assisted Communication
Masoud Sadeghian, Angel Lozano, Gabor Fodor
This paper considers wireless communication assisted by a reconfigurable intelligent surface (RIS), focusing on the two-timescale approach, in which the RIS phase shifts are optimi…
One Target, Many Views: Multi-User Fusion for Collaborative Uplink ISAC
Sajad Daei, Gabor Fodor, Mikael Skoglund
We propose a novel pilot-free multi-user uplink framework for integrated sensing and communication (ISAC) in mm-wave networks, where single-antenna users transmit orthogonal freque…
When Near Becomes Far: From Rayleigh to Optimal Near-Field and Far-Field Boundaries
Sajad Daei, Gabor Fodor, Mikael Skoglund
The transition toward 6G is pushing wireless communication into a regime where the classical plane-wave assumption no longer holds. Millimeter-wave and sub-THz frequencies shrink w…
Offline Reinforcement Learning and Sequence Modeling for Downlink Link Adaptation
Samuele Peri, Alessio Russo, Gabor Fodor +1
Link adaptation (LA) is an essential function in modern wireless communication systems that dynamically adjusts the transmission rate of a communication link to match time- and fre…
Near-Field ISAC in 6G: Addressing Phase Nonlinearity via Lifted Super-Resolution
Sajad Daei, Amirreza Zamani, Saikat Chatterjee +2
Integrated sensing and communications (ISAC) is a promising component of 6G networks, fusing communication and radar technologies to facilitate new services. Additionally, the use…
Improved Downlink Channel Estimation in Time-Varying FDD Massive MIMO Systems
Sajad Daei, Mikael Skoglund, Gabor Fodor
In this work, we address the challenge of accurately obtaining channel state information at the transmitter (CSIT) for frequency division duplexing (FDD) multiple input multiple ou…
Optimal Transmitter Design and Pilot Spacing in MIMO Non-Stationary Aging Channels
Sajad Daei, Gabor Fodor, Mikael Skoglund
This work considers an uplink wireless communication system where multiple users with multiple antennas transmit data frames over dynamic channels. Previous studies have shown that…
Subspace-Informed Matrix Completion
Hamideh. Sadat Fazael Ardakani, Sajad Daei, Arash Amini +2
In this work, we consider the matrix completion problem, where the objective is to reconstruct a low-rank matrix from a few observed entries. A commonly employed approach involves…
Timely and Painless Breakups: Off-the-grid Blind Message Recovery and Users' Demixing
Sajad Daei, Saeed Razavikia, Mikael Skoglund +2
In the near future, the Internet of Things will interconnect billions of devices, forming a vast network where users sporadically transmit short messages through multi-path wireles…
Exploiting Spatial and Temporal Correlations in Massive MIMO Systems Operating Over Non-Stationary Aging Channels
Sajad Daei, Gabor Fodor, Mikael Skoglund
This work investigates a multi-user, multi-antenna uplink wireless system, in which multiple users transmit signals to a base station. Prior research has explored the potential for…
Towards Optimal Pilot Spacing and Power Control in Multi-Antenna Systems Operating Over Non-Stationary Rician Aging Channels
Sajad Daei, Gabor Fodor, Mikael Skoglund +1
Several previous works have addressed the inherent trade-off between allocating resources in the power and time domains to pilot and data signals in multiple input multiple output…