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Found 60 papers, 24 papers with code
Unknown Interference Modeling for Rate Adaptation in Cell-Free Massive MIMO Networks
Co-channel interference poses a challenge in any wireless communication network where the time-frequency resources are reused over different geographical areas.
Wideband Channel Capacity Maximization With Beyond Diagonal RIS Reflection Matrices
We introduce a new algorithm designed to optimize the configuration of the BD-RIS to maximize wideband capacity.
Localization in Massive MIMO Networks: From Near-Field to Far-Field
Source localization is the process of estimating the location of signal sources based on the signals received at different antennas of an antenna array.
Parametric Near-Field Channel Estimation for Extremely Large Aperture Arrays
Accurate channel estimation is critical to fully exploit the beamforming gains when communicating with extremely large aperture arrays.
Nonlinear Distortion Radiated from Large Arrays and Active Reconfigurable Intelligent Surfaces
In this paper, we study the distortion created by nonlinear amplifiers in both ELAAs and active RIS.
A Novel Discrete Phase Shift Design for RIS-Assisted Multi-User MIMO
Reconfigurable intelligent surface (RIS) is a newly-emerged technology that might fundamentally change how wireless networks are operated.
Optimal Dual-Polarized Planar Arrays for Massive Capacity Over Point-to-Point MIMO Channels
We optimize the rank and condition number by identifying the optimal antenna spacing in dual-polarized planar antenna arrays with imperfect isolation.
Broad Beam Reflection for RIS-Assisted MIMO Systems with Planar Arrays
While reconfigurable intelligent surface (RIS)-aided user-specific beamforming has been vastly investigated, the aspect of utilizing RISs for assisting cell-specific transmission has been largely unattended.
A New Polar-Domain Dictionary Design for the Near-field Region of Extremely Large Aperture Arrays
However, when the BS is equipped with an extremely large aperture array, the Fraunhofer distance is huge, causing the UEs to be located in the radiative near-field region.
Dual-Polarized Reconfigurable Intelligent Surface Assisted Broad Beamforming
A reconfigurable intelligent surface (RIS) consists of a large number of low-cost elements that can control the propagation environment seen from a transmitter by intelligently applying phase shifts to impinging signals before reflection.
Energy Harvesting Maximization for Reconfigurable Intelligent Surfaces Using Amplitude Measurements
We prove the convergence of the proposed algorithm to the optimal value for the noiseless scenario.
Combating Inter-Operator Pilot Contamination in Reconfigurable Intelligent Surfaces Assisted Multi-Operator Networks
In this paper, we study a new kind of pilot contamination appearing in multi-operator reconfigurable intelligent surfaces (RIS) assisted networks, where multiple operators provide services to their respective served users.
Parametric Channel Estimation with Short Pilots in RIS-Assisted Near- and Far-Field Communications
This paper proposes a parametric maximum likelihood estimation (MLE) framework for jointly estimating the direct channel between the user and the base station (BS) and the line-of-sight channel between the user and the RIS, in both far-field and near-field scenarios.
Amplitude-Based Sequential Optimization of Energy Harvesting with Reconfigurable Intelligent Surfaces
We propose a sequential phase-alignment algorithm that maximizes the received power based on only power measurements.
Exploiting the Depth and Angular Domains for Massive Near-Field Spatial Multiplexing
This article presents the foundational properties of communication in the radiative near-field region and then exemplifies how these properties enable two unprecedented spatial multiplexing schemes: depth-domain multiplexing of multiple users and angular multiplexing of data streams to a single user.
Finite Beam Depth Analysis for Large Arrays
Furthermore, it is sufficient to characterize the BD for a broadside transmitter, as the beam pattern with a non-broadside transmitter can be approximated by that of a smaller/projected array with a broadside transmitter.
Impact of Pilot Contamination Between Operators With Interfering Reconfigurable Intelligent Surfaces
In this paper, we study the impact of pilot contamination in a system where two operators serve their respective users with the assistance of two wide-band reconfigurable intelligent surfaces (RIS), each belonging to a single operator.
A Bayesian Approach to Characterize Unknown Interference Power in Wireless Networks
The existence of unknown interference is a prevalent problem in wireless communication networks.
25 Years of Signal Processing Advances for Multiantenna Communications
In 1998, mobile phones were still in the process of becoming compact and affordable devices that could be widely utilized in both developed and developing countries.
A New Channel Subspace Characterization for Channel Estimation in RIS-Aided Communications
Reaping the benefits of RIS, however, relies on the accuracy of the channel estimation, which is a challenging task due to the large number of RIS elements.
Efficient LOS Channel Estimation for RIS-Aided Communications Under Non-Stationary Mobility
Reconfigurable intelligent surface (RIS) is a newly-emerged technology that, with its unique features, is considered to be a game changer for future wireless networks.
Cell-Free Massive MIMO in O-RAN: Energy-Aware Joint Orchestration of Cloud, Fronthaul, and Radio Resources
In this paper, we explore the performance and power consumption of cell-free massive MIMO technology in comparison with traditional small-cell systems, in the virtualized O-RAN architecture.
Soft Handover Procedures in mmWave Cell-Free Massive MIMO Networks
The algorithms provide a systematic procedure for initial access and update of the serving APs and assigned pilot sequence to each UE.
Optimized Precoding for MU-MIMO With Fronthaul Quantization
We also propose a heuristic low-complexity approach to quantized precoding.
Energy-Efficient Cell-Free Massive MIMO Through Sparse Large-Scale Fading Processing
In this paper, we propose a sparse distributed processing design for CF mMIMO, where the AP-UE association and long-term signal processing coefficients are jointly optimized.
Channel Estimation under Hardware Impairments: Bayesian Methods versus Deep Learning
This paper considers the impact of general hardware impairments in a multiple-antenna base station and user equipments on the uplink performance.
Exploiting Array Geometry for Reduced-Subspace Channel Estimation in RIS-Aided Communications
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 $N$ reflecting elements are configured properly.
Cell-Free Massive MIMO in Virtualized CRAN: How to Minimize the Total Network Power?
This paper proposes a new cell-free architecture that can be implemented on top of a virtualized cloud radio access network (V-CRAN).
Quantisation-aware Precoding for MU-MIMO with Limited-capacity Fronthaul
Base stations in 5G and beyond use advanced antenna systems (AASs), where multiple passive antenna elements and radio units are integrated into a single box.
Learning-Based Downlink Power Allocation in Cell-Free Massive MIMO Systems
Further, we develop a clustered DNN model where the LSF parameters of a small number of APs, forming a cluster within a relatively large network, are used to jointly approximate the power coefficients of the cluster.
Learning to Perform Downlink Channel Estimation in Massive MIMO Systems
The second one is a deep-learning-based approach that uses a neural network to identify a mapping between the available information and the effective channel gain.
Electromagnetic Interference in RIS-Aided Communications
The model is used to show that electromagnetic interference has a non-negligible impact on communication performance, especially when the size of the RIS grows large.
Configuring an Intelligent Reflecting Surface for Wireless Communications
The IEEE Signal Processing Society is proud to announce the eighth edition of the Signal Processing Cup: an exciting challenge to control a wireless propagation environment using an intelligent reflecting surface.
Reconfigurable Intelligent Surfaces: A Signal Processing Perspective With Wireless Applications
We will provide the formulas and derivations that are required to understand and analyze RIS-aided systems using signal processing, and exemplify how they can be utilized for improved communication, localization, and sensing.
Near- and Far-Field Communications with Large Intelligent Surfaces
This paper studies the uplink spectral efficiency (SE) achieved by two single-antenna user equipments (UEs) communicating with a Large Intelligent Surface (LIS), defined as a planar array consisting of $N$ antennas that each has area $A$.
Deep Learning-based Phase Reconfiguration for Intelligent Reflecting Surfaces
Intelligent reflecting surfaces (IRSs), consisting of reconfigurable metamaterials, have recently attracted attention as a promising cost-effective technology that can bring new features to wireless communications.
Structured Massive Access for Scalable Cell-Free Massive MIMO Systems
However, there are still many unsolved practical issues in cell-free massive MIMO systems, whereof scalable massive access implementation is one of the most vital.
The Bussgang Decomposition of Non-Linear Systems: Basic Theory and MIMO Extensions
The Bussgang decomposition is a popular tool for analyzing the performance of systems that involve such non-linear components.
Joint Power Control and LSFD for Wireless-Powered Cell-Free Massive MIMO
The single-antenna user equipments (UEs) utilize the energy harvested in the downlink to transmit uplink pilot and information signals to the multiple-antenna access points (APs).
Information Theory Signal Processing Information Theory
Power Scaling Laws and Near-Field Behaviors of Massive MIMO and Intelligent Reflecting Surfaces
In this paper, we use a deterministic propagation model for a planar array of arbitrary size, to demonstrate that the mentioned SNR behaviors, and associated power scaling laws, only apply in the far-field.
Information Theory Signal Processing Information Theory
Two Applications of Deep Learning in the Physical Layer of Communication Systems
Deep learning has proved itself to be a powerful tool to develop data-driven signal processing algorithms for challenging engineering problems.
Impact of Backward Crosstalk in 2x2 MIMO Transmitters on NMSE and Spectral Efficiency
We consider backward crosstalk in 2 x 2 transmitters, which is caused by crosstalk from the outputs of the transmitter to the inputs or by the combination of output crosstalk and impedance mismatch.
Channel Estimation in Massive MIMO under Hardware Non-Linearities: Bayesian Methods versus Deep Learning
First, Bussgang decomposition-based effective channels and distortion characteristics are analytically derived and the spectral efficiency (SE) achieved by several receivers are explored for third-order non-linearities.
Information Theory Signal Processing Information Theory
Optimizing Information Freshness in a Multiple Access Channel with Heterogeneous Devices
We formulate an optimization problem that aims at minimizing the average age of information (AoI) of the EH node subject to the queue stability condition of the grid-connected node.
Information Theory Networking and Internet Architecture Information Theory
Scalable Cell-Free Massive MIMO Systems
The main challenge is to achieve the benefits of cell-free operation in a practically feasible way, with computational complexity and fronthaul requirements that are scalable to large networks with many users.
Information Theory Signal Processing Information Theory
Intelligent Reflecting Surface vs. Decode-and-Forward: How Large Surfaces Are Needed to Beat Relaying?
The rate and energy efficiency of wireless channels can be improved by deploying software-controlled metasurfaces to reflect signals from the source to the destination, especially when the direct path is weak.
Information Theory Information Theory
Making Cell-Free Massive MIMO Competitive With MMSE Processing and Centralized Implementation
Cell-free Massive MIMO is considered as a promising technology for satisfying the increasing number of users and high rate expectations in beyond-5G networks.
Information Theory Signal Processing Information Theory
Power Control in Cellular Massive MIMO with Varying User Activity: A Deep Learning Solution
We first consider the sum spectral efficiency (SE) optimization problem for systems with a dynamically varying number of active users.
Information Theory Information Theory
How Energy-Efficient Can a Wireless Communication System Become?
Is this roughly as energy-efficient future systems (5G and beyond) can become, or are we still far from the physical limits?
Information Theory Information Theory
Hardware Distortion Correlation Has Negligible Impact on UL Massive MIMO Spectral Efficiency
To determine when this approximation is accurate, basic properties of distortion correlation are first uncovered.
Information Theory Information Theory
Large-Scale-Fading Decoding in Cellular Massive MIMO Systems with Spatially Correlated Channels
The numerical results show that both data power control and LSFD improves the sum SE performance over single-layer decoding multi-cell Massive MIMO systems.
Information Theory Information Theory
Massive MIMO in Sub-6 GHz and mmWave: Physical, Practical, and Use-Case Differences
The use of base stations (BSs) and access points (APs) with a large number of antennas, called Massive MIMO (multiple-input multiple-output), is a key technology for increasing the capacity of 5G networks and beyond.
Information Theory Information Theory
Massive MIMO has Unlimited Capacity
The capacity of cellular networks can be improved by the unprecedented array gain and spatial multiplexing offered by Massive MIMO.
Information Theory Information Theory
A Random Access Protocol for Pilot Allocation in Crowded Massive MIMO Systems
The Massive MIMO (multiple-input multiple-output) technology has great potential to manage the rapid growth of wireless data traffic.
Information Theory Networking and Internet Architecture Information Theory
Optimal Multiuser Transmit Beamforming: A Difficult Problem with a Simple Solution Structure
A high signal power is achieved by transmitting the same data signal from all antennas, but with different amplitudes and phases, such that the signal components add coherently at the user.
Information Theory Information Theory
Optimal Design of Energy-Efficient Multi-User MIMO Systems: Is Massive MIMO the Answer?
Numerical and analytical results show that the maximal EE is achieved by a massive MIMO setup wherein hundreds of antennas are deployed to serve a relatively large number of users using ZF processing.
Information Theory Networking and Internet Architecture Information Theory
A New Look at Dual-Hop Relaying: Performance Limits with Hardware Impairments
Such approximations make sense in low-rate systems, but can lead to very misleading results when analyzing future high-rate systems.
Information Theory Information Theory
Massive MIMO Systems with Non-Ideal Hardware: Energy Efficiency, Estimation, and Capacity Limits
The use of large-scale antenna arrays can bring substantial improvements in energy and/or spectral efficiency to wireless systems due to the greatly improved spatial resolution and array gain.
Information Theory Information Theory
Capacity Limits and Multiplexing Gains of MIMO Channels with Transceiver Impairments
The capacity of ideal MIMO channels has a high-SNR slope that equals the minimum of the number of transmit and receive antennas.
Information Theory Information Theory
Receive Combining vs. Multi-Stream Multiplexing in Downlink Systems with Multi-Antenna Users
Analytic results are derived to show how user selection, spatial correlation, heterogeneous user conditions, and imperfect channel acquisition (quantization or estimation errors) affect the performance when sending the maximal number of streams or one stream per scheduled user---the two extremes in data stream allocation.
Information Theory Information Theory
