Search Results for author: Octavia A. Dobre

Found 49 papers, 0 papers with code

Beamforming Optimization for Active RIS-Aided Multiuser Communications With Hardware Impairments

no code implementations16 Feb 2024 Zhangjie Peng, Zhibo Zhang, Cunhua Pan, Marco Di Renzo, Octavia A. Dobre, Jiangzhou Wang

Specifically, by exploiting the majorization-minimization approach, each subproblem is reformulated into a tractable surrogate problem, whose closed-form solutions are obtained by Lagrange dual decomposition approach and element-wise alternating sequential optimization method.

Semi-Passive Intelligent Reflecting Surface Enabled Sensing Systems

no code implementations5 Feb 2024 Qiaoyan Peng, Qingqing Wu, Wen Chen, Shaodan Ma, Ming-Min Zhao, Octavia A. Dobre

Towards this goal, we begin by deriving the CRB for the direction-of-arrival (DoA) estimation in closed-form and then theoretically analyze the IRS reflecting elements and sensors allocation design based on the CRB under the point target case with a single-antenna base station (BS).

Deep-Learning-Based Channel Estimation for IRS-Assisted ISAC System

no code implementations29 Jan 2024 Yu Liu, Ibrahim Al-Nahhal, Octavia A. Dobre, Fanggang Wang

A deep-learning framework is proposed to estimate the sensing and communication (S&C) channels in such a system.

Deep-Learning Channel Estimation for IRS-Assisted Integrated Sensing and Communication System

no code implementations29 Jan 2024 Yu Liu, Ibrahim Al-Nahhal, Octavia A. Dobre, Fanggang Wang

This problem is challenging due to the lack of signal processing capacity in passive IRS, as well as the presence of mutual interference between sensing and communication (SAC) signals in ISAC systems.

Extreme Learning Machine-based Channel Estimation in IRS-Assisted Multi-User ISAC System

no code implementations29 Jan 2024 Yu Liu, Ibrahim Al-Nahhal, Octavia A. Dobre, Fanggang Wang, Hyundong Shin

Multi-user integrated sensing and communication (ISAC) assisted by intelligent reflecting surface (IRS) has been recently investigated to provide a high spectral and energy efficiency transmission.

Efficient Neural Network

Large Language Model Enhanced Multi-Agent Systems for 6G Communications

no code implementations13 Dec 2023 Feibo Jiang, Li Dong, Yubo Peng, Kezhi Wang, Kun Yang, Cunhua Pan, Dusit Niyato, Octavia A. Dobre

The rapid development of the Large Language Model (LLM) presents huge opportunities for 6G communications, e. g., network optimization and management by allowing users to input task requirements to LLMs by nature language.

Language Modelling Large Language Model +2

Simultaneous Beam Training and Target Sensing in ISAC Systems with RIS

no code implementations25 Nov 2023 Kangjian Chen, Chenhao Qi, Octavia A. Dobre, Geoffrey Ye Li

Based on the SBTTS and PAOE schemes, we further compute the angle-of-arrival and angle-of-departure for the channels between the RIS and the UTs by exploiting the geometry relationship to accomplish the beam alignment of the ISAC system.

GNN-Based Beamforming for Sum-Rate Maximization in MU-MISO Networks

no code implementations7 Nov 2023 Yuhang Li, Yang Lu, Bo Ai, Octavia A. Dobre, Zhiguo Ding, Dusit Niyato

This paper studies the GNN-based learning approach for the sum-rate maximization in multiple-user multiple-input single-output (MU-MISO) networks subject to the users' individual data rate requirements and the power budget of the base station.

Liquid Crystal-Based RIS for VLC Transmitters: Performance Analysis, Challenges, and Opportunities

no code implementations18 Aug 2023 Sylvester Aboagye, Telex M. N. Ngatched, Alain R. Ndjiongue, Octavia A. Dobre, Hyundong Shin

This article presents a novel approach of using reconfigurable intelligent surfaces (RISs) in the transmitter of indoor visible light communication (VLC) systems to enhance data rate uniformity and maintain adequate illumination.

Physical Layer Security for NOMA Systems: Requirements, Issues, and Recommendations

no code implementations10 Aug 2023 Saeid Pakravan, Jean-Yves Chouinard, Xingwang Li, Ming Zeng, Wanming Hao, Quoc-Viet Pham, Octavia A. Dobre

Nevertheless, from a security view-point, when multiple users are utilizing the same time-frequency resource, there may be concerns regarding keeping information confidential.

Deep Reinforcement Learning for RIS-Assisted FD Systems: Single or Distributed RIS?

no code implementations15 Aug 2022 Alice Faisal, Ibrahim Al-Nahhal, Octavia A. Dobre, Telex M. N. Ngatched

It is further shown that the proposed algorithm significantly improves the sum-rate compared to the non-optimized scenario in both single and distributed RIS deployment schemes.

reinforcement-learning Reinforcement Learning (RL)

Two-timescale Resource Allocation for Automated Networks in IIoT

no code implementations24 Mar 2022 Yanhua He, Yun Ren, Zhenyu Zhou, Shahid Mumtaz, Saba Al-Rubaye, Antonios Tsourdos, Octavia A. Dobre

The rapid technological advances of cellular technologies will revolutionize network automation in industrial internet of things (IIoT).

energy management Management +2

Federated Learning for Smart Healthcare: A Survey

no code implementations16 Nov 2021 Dinh C. Nguyen, Quoc-Viet Pham, Pubudu N. Pathirana, Ming Ding, Aruna Seneviratne, Zihuai Lin, Octavia A. Dobre, Won-Joo Hwang

Recent advances in communication technologies and Internet-of-Medical-Things have transformed smart healthcare enabled by artificial intelligence (AI).

Federated Learning Management

Hybrid-Layers Neural Network Architectures for Modeling the Self-Interference in Full-Duplex Systems

no code implementations18 Oct 2021 Mohamed Elsayed, Ahmad A. Aziz El-Banna, Octavia A. Dobre, Wanyi Shiu, Peiwei Wang

In contrast to the state-of-the-art NNs that employ dense or recurrent layers for SI modeling, the proposed NNs exploit, in a novel manner, a combination of different hidden layers (e. g., convolutional, recurrent, and/or dense) in order to model the SI with lower computational complexity than the polynomial and the state-of-the-art NN-based cancelers.

Perturbation Theory-Aided Learned Digital Back-Propagation Scheme for Optical Fiber Nonlinearity Compensation

no code implementations11 Oct 2021 Xiang Lin, Shenghang Luo, Sunish Kumar Orappanpara Soman, Octavia A. Dobre, Lutz Lampe, Deyuan Chang, Chuandong Li

The proposed scheme is evaluated by numerical simulations of a single carrier optical fiber communication system operating at 32 Gbaud with 64-quadrature amplitude modulation and 20*80 km transmission distance.

Deep Reinforcement Learning for Optimizing RIS-Assisted HD-FD Wireless Systems

no code implementations10 Oct 2021 Alice Faisal, Ibrahim Al-Nahhal, Octavia A. Dobre, Telex M. N. Ngatched

The complexity analysis and Monte Carlo simulations illustrate that the proposed DRL algorithm significantly improves the rate compared to the non-optimized scenario in both HD and FD operating modes using a single parameter setting.

reinforcement-learning Reinforcement Learning (RL)

Integration of Backscatter Communication with Multi-cell NOMA: A Spectral Efficiency Optimization under Imperfect SIC

no code implementations23 Sep 2021 Wali Ullah Khan, Eva Lagunas, Asad Mahmood, Zain Ali, Symeon Chatzinotas, Björn Ottersten, Octavia A. Dobre

This paper proposes a new optimization approach to enhance the spectral efficiency of nonorthogonal multiple access (NOMA)-BC network.

Deep Learning-based Time-varying Channel Estimation for RIS Assisted Communication

no code implementations12 Aug 2021 Meng Xu, Shun Zhang, Jianpeng Ma, Octavia A. Dobre

Reconfigurable intelligent surface (RIS) is considered as a revolutionary technology for future wireless communication networks.

Time Series Time Series Analysis

Deep Learning Based Antenna-time Domain Channel Extrapolation for Hybrid mmWave Massive MIMO

no code implementations9 Aug 2021 Shunbo Zhang, Shun Zhang, Jianpeng Ma, Tian Liu, Octavia A. Dobre

We design a latent ordinary differential equation (ODE)-based network under the variational auto-encoder (VAE) framework to learn the mapping function from the partial uplink channels to the full downlink ones at the BS side.

Deep Reinforcement Learning for Intelligent Reflecting Surface-assisted D2D Communications

no code implementations6 Aug 2021 Khoi Khac Nguyen, Antonino Masaracchia, Cheng Yin, Long D. Nguyen, Octavia A. Dobre, Trung Q. Duong

In this paper, we propose a deep reinforcement learning (DRL) approach for solving the optimisation problem of the network's sum-rate in device-to-device (D2D) communications supported by an intelligent reflecting surface (IRS).

reinforcement-learning Reinforcement Learning (RL)

Cascaded Channel Estimation for RIS Assisted mmWave MIMO Transmissions

no code implementations19 Jun 2021 Yushan Liu, Shun Zhang, Feifei Gao, Jie Tang, Octavia A. Dobre

Channel estimation is challenging for the reconfigurable intelligence surface (RIS) assisted millimeter wave (mmWave) communications.

Deep Learning Based RIS Channel Extrapolation with Element-grouping

no code implementations14 May 2021 Shunbo Zhang, Shun Zhang, Feifei Gao, Jianpeng Ma, Octavia A. Dobre

Reconfigurable intelligent surface (RIS) is considered as a revolutionary technology for future wireless communication networks.

Coverage Characterization of STAR-RIS Networks: NOMA and OMA

no code implementations20 Apr 2021 Chenyu Wu, Yuanwei Liu, Xidong Mu, Xuemai Gu, Octavia A. Dobre

A sum coverage range maximization problem is formulated for both non-orthogonal multiple access (NOMA) and orthogonal multiple access (OMA), where the resource allocation at the access point and the transmission and reflection coefficients at the STAR-RIS are jointly optimized to satisfy the communication requirements of users.

Design of a Power Amplifying-RIS for Free-Space Optical Communication Systems

no code implementations8 Apr 2021 Alain R. Ndjiongue, Telex M. N. Ngatched, Octavia A. Dobre, Harald Haas

Leveraging on this capacity of a doped LC, we mitigate the double-attenuation faced by the transmitted signal.

Incremental Relaying for Power Line Communication: Performance Analysis and Power Allocation

no code implementations9 Mar 2021 Ankit Dubey, Chinmoy Kundu, Telex M. N. Ngatched, Octavia A. Dobre, Ranjan K. Mallik

By employing power allocation to minimize the outage probability, it is realized that the power should be allocated in accordance with the inter-node distances and channel parameters.

Deep Learning based Channel Extrapolation for Large-Scale Antenna Systems: Opportunities, Challenges and Solutions

no code implementations25 Feb 2021 Shun Zhang, Yushan Liu, Feifei Gao, Chengwen Xing, Jianping An, Octavia A. Dobre

With the depletion of spectrum, wireless communication systems turn to exploit large antenna arrays to achieve the degree of freedom in space domain, such as millimeter wave massive multi-input multioutput (MIMO), reconfigurable intelligent surface assisted communications and cell-free massive MIMO.

Information Theory Signal Processing Information Theory

Recurrent Neural Network Assisted Transmitter Selection for Secrecy in Cognitive Radio Network

no code implementations16 Feb 2021 Shalini Tripathi, Chinmoy Kundu, Octavia A. Dobre, Ankur Bansal, Mark F. Flanagan

In this paper, we apply the long short-term memory (LSTM), an advanced recurrent neural network based machine learning (ML) technique, to the problem of transmitter selection (TS) for secrecy in an underlay small-cell cognitive radio network with unreliable backhaul connections.

Performance Analysis of RIS-Based nT-FSO Link Over G-G Turbulence With Pointing Errors

no code implementations6 Feb 2021 Alain R. Ndjiongue, Telex M. N. Ngatched, Octavia A. Dobre, Ana G. Armada, Harald Haas

One of the main problems faced by communication systems is the presence of skip-zones in the targeted areas.

STAR-RISs: Simultaneous Transmitting and Reflecting Reconfigurable Intelligent Surfaces

no code implementations24 Jan 2021 Jiaqi Xu, Yuanwei Liu, Xidong Mu, Octavia A. Dobre

In this letter, simultaneous transmitting and reflecting reconfigurable intelligent surfaces (STAR-RISs) are studied.

Re-configurable Intelligent Surface-based VLC Receivers Using Tunable Liquid-crystals: The Concept

no code implementations7 Jan 2021 Alain R. Ndjiongue, Telex M. N. Ngatched, Octavia A. Dobre, Harald Haas

Visible light communication (VLC) enables access to huge unlicensed bandwidth, a higher security level, and no radio frequency interference.

Ordinary Differential Equation-based CNN for Channel Extrapolation over RIS-assisted Communication

no code implementations22 Dec 2020 Meng Xu, Shun Zhang, Caijun Zhong, Jianpeng Ma, Octavia A. Dobre

The reconfigurable intelligent surface (RIS) is considered as a promising new technology for reconfiguring wireless communication environments.

Information Theory Information Theory

Energy Efficiency Maximization in RIS-Aided Cell-Free Network with Limited Backhaul

no code implementations21 Dec 2020 Quang Nhat Le, Van-Dinh Nguyen, Octavia A. Dobre, Ruiqin Zhao

Integrating the reconfigurable intelligent surface in a cell-free (RIS-CF) network is an effective solution to improve the capacity and coverage of future wireless systems with low cost and power consumption.

Robotic Communications for 5G and Beyond: Challenges and Research Opportunities

no code implementations9 Dec 2020 Yuanwei Liu, Xiao Liu, Xinyu Gao, Xidong Mu, Xiangwei Zhou, Octavia A. Dobre, H. Vincent Poor

Furthermore, dynamic trajectory design and resource allocation for both indoor and outdoor robots are provided to verify the performance of robotic communications in the context of typical robotic application scenarios.

Robotics Systems and Control Signal Processing Systems and Control

Full-Duplex Non-Orthogonal Multiple Access Cooperative Overlay Spectrum-Sharing Networks with SWIPT

no code implementations19 Nov 2020 Quang Nhat Le, Animesh Yadav, Nam-Phong Nguyen, Octavia A. Dobre, Ruiqin Zhao

Numerical results show that FD, SWIPT, and NOMA techniques greatly boost the performance of cooperative spectrum-sharing network in terms of outage probability, system throughput, and sum rate compared to that of half-duplex NOMA and the conventional orthogonal multiple access-time division multiple access networks.

STS

Learning-Assisted User Clustering in Cell-Free Massive MIMO-NOMA Networks

no code implementations15 Nov 2020 Quang Nhat Le, Van-Dinh Nguyen, Nam-Phong Nguyen, Symeon Chatzinotas, Octavia A. Dobre, Ruiqin Zhao

To address this problem, we develop two efficient unsupervised machine learning (ML) based UC algorithms, namely k-means++ and improved k-means++, to effectively cluster users into disjoint clusters in cell-free massive multiple-input multiple-output (CFmMIMO) system.

Clustering Fairness

Low Complexity Neural Network Structures for Self-Interference Cancellation in Full-Duplex Radio

no code implementations23 Sep 2020 Mohamed Elsayed, Ahmad A. Aziz El-Banna, Octavia A. Dobre, Wanyi Shiu, Peiwei Wang

The core idea of these two structures is to mimic the non-linearity and memory effect introduced to the SI signal in order to achieve proper SI cancellation while exhibiting low computational complexity.

Towards the Use of Re-configurable Intelligent Surfaces in VLC Systems: Beam Steering

no code implementations15 Sep 2020 Alain R. Ndjiongue, Telex M. N. Ngatched, Octavia A. Dobre, Harald Haas

On the other hand, re-configurable intelligent surface (RIS) is a technology exploited in radio frequency to solve dead zones and loss of signal.

Deep Learning Based Antenna Selection for Channel Extrapolation in FDD Massive MIMO

no code implementations3 Sep 2020 Yindi Yang, Shun Zhang, Feifei Gao, Chao Xu, Jianpeng Ma, Octavia A. Dobre

In massive multiple-input multiple-output (MIMO) systems, the large number of antennas would bring a great challenge for the acquisition of the accurate channel state information, especially in the frequency division duplex mode.

On the Complexity Reduction of Uplink Sparse Code Multiple Access for Spatial Modulation

no code implementations17 Aug 2020 Ibrahim Al-Nahhal, Octavia A. Dobre, Salama Ikki

The first algorithm is referred to as successive user detection (SUD), while the second algorithm is the modified version of SUD, namely modified SUD (MSUD).

Rate-Splitting Multiple Access: Unifying NOMA and SDMA in MISO VLC Channels

no code implementations24 Jul 2020 Shimaa Naser, Lina Bariah, Wael Jaafar, Sami Muhaidat, Paschalis C. Sofotasios, Mahmoud Al-Qutayri, Octavia A. Dobre

Then, we introduce rate-splitting multiple access (RSMA), which was initially proposed for RF systems and discuss its potentials in VLC systems.

Large Intelligent Surface Assisted Non-Orthogonal Multiple Access: Performance Analysis

no code implementations19 Jul 2020 Lina Bariah, Sami Muhaidat, Paschalis C. Sofotasios, Faissal El Bouanani, Octavia A. Dobre, Walaa Hamouda

Specifically, we consider a downlink NOMA system, in which data transmission between a base station (BS) and $L$ NOMA users is assisted by an LIS comprising $M$ reflective elements.

A Novel Heap-based Pilot Assignment for Full Duplex Cell-Free Massive MIMO with Zero-Forcing

no code implementations8 Jul 2020 Hieu V. Nguyen, Van-Dinh Nguyen, Octavia A. Dobre, Shree Krishna Sharma, Symeon Chatzinotas, Björn Ottersten, Oh-Soon Shin

This paper investigates the combined benefits of full-duplex (FD) and cell-free massive multiple-input multipleoutput (CF-mMIMO), where a large number of distributed access points (APs) having FD capability simultaneously serve numerous uplink and downlink user equipments (UEs) on the same time-frequency resources.

Robust Design

Spectral-Energy Efficiency Trade-off-based Beamforming Design for MISO Non-Orthogonal Multiple Access Systems

no code implementations19 Jun 2020 Haitham Al-Obiedollah, Kanapathippillai Cumanan, Jeyarajan Thiyagalingam, Jie Tang, Alister G. Burr, Zhiguo Ding, Octavia A. Dobre

In particular, we formulate a joint SE-EE based design as a multi-objective optimization (MOO) problem to achieve a good tradeoff between the two performance metrics.

A Prospective Look: Key Enabling Technologies, Applications and Open Research Topics in 6G Networks

no code implementations9 Apr 2020 Lina Bariah, Lina Mohjazi, Sami Muhaidat, Paschalis C. Sofotasios, Gunes Karabulut Kurt, Halim Yanikomeroglu, Octavia A. Dobre

To accommodate the stringent requirements of their prospective applications, which are data-driven and defined by extremely low-latency, ultra-reliable, fast and seamless wireless connectivity, research initiatives are currently focusing on a progressive roadmap towards the sixth generation (6G) networks.

Fiber Nonlinearity Mitigation via the Parzen Window Classifier for Dispersion Managed and Unmanaged Links

no code implementations17 Sep 2019 Abdelkerim Amari, Xiang Lin, Octavia A. Dobre, Ramachandran Venkatesan, Alex Alvarado

Machine learning techniques have recently received significant attention as promising approaches to deal with the optical channel impairments, and in particular, the nonlinear effects.

BIG-bench Machine Learning

A Machine Learning-Based Detection Technique for Optical Fiber Nonlinearity Mitigation

no code implementations27 Feb 2019 Abdelkerim Amari, Xiang Lin, Octavia A. Dobre, Ramachandran Venkatesan, Alex Alvarado

In this case, digital back propagation compensates for the deterministic nonlinearity and the Parzen window deals with the stochastic nonlinear signal-noise interactions, which are not taken into account by digital back propagation.

BIG-bench Machine Learning General Classification

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