151 citations · 220 across the 12 of their papers we have counts for
15 papers
Parametric Channel Estimation for RIS-Assisted Wideband Systems
Alva Kosasih, Ozlem Tugfe Demir, Emil Bjornson
A reconfigurable intelligent surface (RIS) alters the reflection of incoming signals based on the phase-shift configuration assigned to its elements. This feature can be used to im…
Towards 6G MIMO: Massive Spatial Multiplexing, Dense Arrays, and Interplay Between Electromagnetics and Processing
Emil Björnson, Chan-Byoung Chae, Robert W. Heath +7
The increasing demand for wireless data transfer has been the driving force behind the widespread adoption of Massive MIMO (multiple-input multiple-output) technology in 5G. The ne…
A New Polar-Domain Dictionary Design for the Near-field Region of Extremely Large Aperture Arrays
Özlem Tuğfe Demir, Emil Björnson
A grid of orthogonal beams with zero column coherence can be easily constructed to cover all prospective user equipments (UEs) in the far-field region of a multiple-antenna base st…
Technology Trends for Massive MIMO towards 6G
Yiming Huo, Xingqin Lin, Boya Di +6
At the dawn of the next-generation wireless systems and networks, massive multiple-input multiple-output (MIMO) has been envisioned as one of the enabling technologies. With the co…
Cell-Free Massive MIMO in O-RAN: Energy-Aware Joint Orchestration of Cloud, Fronthaul, and Radio Resources
Özlem Tuğfe Demir, Meysam Masoudi, Emil Björnson +1
For the energy-efficient deployment of cell-free massive MIMO functionality in a practical wireless network, the end-to-end (from radio site to the cloud) energy-aware operation is…
Exploiting Array Geometry for Reduced-Subspace Channel Estimation in RIS-Aided Communications
Özlem Tuğfe Demir, Emil Björnson, Luca Sanguinetti
A reconfigurable intelligent surface (RIS) can be used to improve the channel gain between a base station (BS) and user equipment (UE), but only if its reflecting elements are…
Cell-Free Massive MIMO in Virtualized CRAN: How to Minimize the Total Network Power?
Özlem Tuğfe Demir, Meysam Masoudi, Emil Björnson +1
Previous works on cell-free massive MIMO mostly consider physical-layer and fronthaul transport aspects. How to deploy cell-free massive MIMO functionality in a practical wireless…
RIS-Assisted Massive MIMO with Multi-Specular Spatially Correlated Fading
Özlem Tuğfe Demir, Emil Björnson
Reconfigurable intelligent surfaces (RISs) have attracted great attention as a potential beyond 5G technology. These surfaces consist of many passive elements of metamaterials whos…
Foundations of User-Centric Cell-Free Massive MIMO
Özlem Tuğfe Demir, Emil Björnson, Luca Sanguinetti
Imagine a coverage area where each mobile device is communicating with a preferred set of wireless access points (among many) that are selected based on its needs and cooperate to…
Cell-Free Massive MIMO with Large-Scale Fading Decoding and Dynamic Cooperation Clustering
Özlem Tuğfe Demir, Emil Björnson, Luca Sanguinetti
This paper considers the uplink of user-centric cell-free massive MIMO (multiple-input multiple-output) systems. We utilize the user-centric dynamic cooperation clustering (DCC) fr…
Large-Scale Fading Precoding for Spatially Correlated Rician Fading with Phase Shifts
Özlem Tuğfe Demir, Emil Björnson
We consider large-scale fading precoding (LSFP), which is a two-layer precoding scheme in the downlink of multi-cell massive MIMO (multiple-input multiple-output) systems to suppre…
The Bussgang Decomposition of Non-Linear Systems: Basic Theory and MIMO Extensions
Özlem Tuğfe Demir, Emil Björnson
Many of the systems that appear in various signal processing applications are non-linear, for example, due to hardware impairments such as non-linear amplifiers and finite-resoluti…
ADMM-Based One-Bit Quantized Signal Detection for Massive MIMO Systems with Hardware Impairments
Özlem Tugfe Demir, Emil Björnson
This paper considers signal detection in massive multiple-input multiple-output (MIMO) systems with general additive hardware impairments and one-bit quantization. First, we presen…
Large-Scale Fading Precoding for Maximizing the Product of SINRs
Özlem Tugfe Demir, Emil Björnson
This paper considers the large-scale fading precoding design for mitigating the pilot contamination in the downlink of multi-cell massive MIMO (multiple-input multiple-output) syst…
Max-Min Fair Wireless-Powered Cell-Free Massive MIMO for Uncorrelated Rician Fading Channels
Özlem Tuğfe Demir, Emil Björnson
This paper considers cell-free massive multiple-input multiple-output systems where the multiple-antenna access points (APs) assist the single-antenna user equipments (UEs) by wire…