75 citations · 167 across the 35 of their papers we have counts for
36 papers
Learning Energy-Efficient Modular Arrays under Hardware Non-linearities
Özlem Tuğfe Demir, Alva Kosasih
This paper investigates the joint optimization of power allocation and antenna activation in sparse extremely large aperture array systems operating under power amplifier non-linea…
Performance Evaluation of Movable Antenna Arrays in Wideband Multi-User MIMO Systems
Amna Irshad, Emil Björnson, Alva Kosasih +1
Future wireless networks are expected to support increasingly high data rates and user densities, motivating advanced multi-antenna architectures capable of adapting to dynamic pro…
Quantized Precoding for Maximizing Sum Rate in MU-MIMO Systems with Constrained Fronthaul
Yasaman Khorsandmanesh, Alva Kosasih, Emil Björnson +1
This paper studies a downlink multi-user multiple-input multiple-output (MU-MIMO) system, where the precoding matrix is computed at a baseband unit (BBU) and then transmitted to th…
Maximum A Posteriori Probability Channel Tracking with an Intelligent Transmitting Surface
Parisa Ramezani, Alva Kosasih, Emil Björnson
This paper considers an intelligent transmitting surface (ITS) integrated into a base station and develops a low-overhead maximum a posteriori (MAP) probability channel tracking me…
From Antenna Abundance to Antenna Intelligence in 6G Gigantic MIMO Systems
Emil Björnson, Amna Irshad, Özlem Tugfe Demir +3
Current cellular systems achieve high spectral efficiency through Massive MIMO, which leverages an abundance of antennas to create favorable propagation conditions for multiuser sp…
Optimizing Movable Antennas in Wideband Multi-User MIMO With Hardware Impairments
Amna Irshad, Emil Björnson, Alva Kosasih +1
Movable antennas represent an emerging field in telecommunication research and a potential approach to achieving higher data rates in multiple-input multiple-output (MIMO) communic…
Near-Field Beamfocusing, Localization, and Channel Estimation with Modular Linear Arrays
Alva Kosasih, Özlem Tuğfe Demir, Emil Björnson
This paper investigates how near-field beamfocusing can be achieved using a modular linear array (MLA), composed of multiple widely spaced uniform linear arrays (ULAs). The MLA arc…
Limited-Resolution Hybrid Analog-Digital Precoding Design Using MIMO Detection Methods
Parisa Ramezani, Alva Kosasih, Emil Björnson
While fully-digital precoding achieves superior performance in massive MIMO systems, it comes with significant drawbacks in terms of computational complexity and power consumption,…
Pre-Optimized Irregular Arrays versus Moveable Antennas in Multi-User MIMO Systems
Amna Irshad, Alva Kosasih, Vitaly Petrov +1
Massive multiple-input multiple-output (MIMO) systems exploit the spatial diversity achieved with an array of many antennas to perform spatial multiplexing of many users. Similar p…
A Novel Hybrid Precoder With Low-Resolution Phase Shifters and Fronthaul Capacity Limitation
Parisa Ramezani, Alva Kosasih, Emil Björnson
In massive MIMO systems, fully digital precoding offers high performance but has significant implementation complexity and energy consumption, particularly at millimeter frequencie…
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…
Achieving Beamfocusing via Two Separated Uniform Linear Arrays
Alva Kosasih, Özlem Tugfe Demir, Emil Björnson
This paper investigates coordinated beamforming using a modular linear array (MLA), composed of a pair of physically separated uniform linear arrays (ULAs), treated as sub-arrays.…
Graph Neural Network-based End-to-End Learning for Multi-User MIMO Systems
Hao Chang, Hoang Triet Vo, Alva Kosasih +2
End-to-end (E2E) learning has recently been proposed to jointly design the modulator and symbol detector by using deep neural networks (DNNs). However, existing schemes lack suffic…
An Efficient Modified MUSIC Algorithm for RIS-Assisted Near-Field Localization
Parisa Ramezani, Alva Kosasih, Emil Björnson
In this paper, we consider a single-anchor localization system assisted by a reconfigurable intelligent surface (RIS), where the objective is to localize multiple user equipments (…
Symbol-Level Precoding for Near-Field ISAC
Nithin Babu, Alva Kosasih, Christos Masouros +1
The forthcoming 6G and beyond wireless networks are anticipated to introduce new groundbreaking applications, such as Integrated Sensing and Communications (ISAC), potentially leve…
Spatial Frequencies and Degrees of Freedom: Their Roles in Near-Field Communications
Alva Kosasih, Özlem Tuğfe Demir, Nikolaos Kolomvakis +1
As wireless technology begins to utilize physically larger arrays and/or higher frequencies, the transmitter and receiver will reside in each other's radiative near field. This fac…
Enabling 6G Performance in the Upper Mid-Band by Transitioning From Massive to Gigantic MIMO
Emil Björnson, Ferdi Kara, Nikolaos Kolomvakis +3
The initial 6G networks will likely operate in the upper mid-band (7-24 GHz), which has decent propagation conditions but underwhelming new spectrum availability. In this paper, we…
Spatial Correlation Modeling and RS-LS Estimation of Near-Field Channels with Uniform Planar Arrays
Özlem Tuğfe Demir, Alva Kosasih, Emil Björnson
Extremely large aperture arrays (ELAAs) can offer massive spatial multiplexing gains in the radiative near-field region in beyond 5G systems. While near-field channel modeling for…
Accurate Direct Positioning in Distributed MIMO Using Delay-Doppler Channel Measurements
Benjamin J. B. Deutschmann, Christian Nelson, Mikael Henriksson +5
Distributed multiple-input multiple-output (D-MIMO) is a promising technology for simultaneous communication and positioning. However, phase synchronization between multiple access…
Parametric Near-Field Channel Estimation for Extremely Large Aperture Arrays
Alva Kosasih, Özlem Tuğfe Demir, Emil Björnson
Accurate channel estimation is critical to fully exploit the beamforming gains when communicating with extremely large aperture arrays. The propagation distances between the user a…
Nonlinear Distortion Radiated from Large Arrays and Active Reconfigurable Intelligent Surfaces
Nikolaos Kolomvakis, Alva Kosasih, Emil Björnson
Extremely large aperture arrays (ELAAs) and reconfigurable intelligent surfaces (RISs) are candidate enablers to realize connectivity goals for the sixth-generation (6G) wireless n…
Optimal Dual-Polarized Planar Arrays for Massive Capacity Over Point-to-Point MIMO Channels
Amna Irshad, Alva Kosasih, Emil Björnson +1
Future wireless networks must provide ever higher data rates. The available bandwidth increases roughly linearly as we increase the carrier frequency, but the range shrinks drastic…
Exploiting the Depth and Angular Domains for Massive Near-Field Spatial Multiplexing
Parisa Ramezani, Alva Kosasih, Amna Irshad +1
In this article, we present our vision for how extremely large aperture arrays (ELAAs), equipped with hundreds or thousands of antennas, can play a major role in future 6G networks…
Finite Beam Depth Analysis for Large Arrays
Alva Kosasih, Emil Björnson
Most wireless communication systems operate in the far-field region of antennas and antenna arrays, where waves are planar and beams have infinite depth. When antenna arrays become…