检索结果-内蒙古大学图书馆

Joint Spectrum, Precoding, and Phase Shifts Design for RIS-Aided multiuser MIMO THz Systems

IEEE TRANSACTIONS ON COMMUNICATIONS 2024年第8期72卷 5087-5101页

作者： Mehrabian, Ali Wong, Vincent W. S. Univ British Columbia Dept Elect & Comp Engn Vancouver BC V6T 1Z4 Canada

Terahertz (THz) wireless systems aim to support content-rich applications with ultra-high data rate. Due to high molecular absorption, THz signals experience severe path loss over long distance. To alleviate distance limitation, reconfigurable intelligent surface (RIS) can improve the coverage range. Adaptive sub-band bandwidth (ASB) allocation can mitigate absorption attenuation by allocating THz sub-bands with variable bandwidth to the users. However, in ASB allocation, since the bandwidth of sub-bands may not be known a priori, accurate channel estimation is challenging. To overcome this issue, in this paper, we propose a metapath-based heterogeneous graph-transformer network (MHGphormer) to bypass the channel estimation phase. We formulate a sum-rate maximization problem with quality-of-service (QoS) constraints in a RIS-aided multiuser multiple-input multiple-output (MU-MIMO) THz system to optimize the precoding, phase shifts, and ASB allocation. The proposed MHGphormer parameterizes the mapping from input (e.g., location information, users' minimum data rate) to the optimized system parameters via unsupervised learning. The proposed MHGphormer has the permutation invariance/equivariance property. It can be applied to systems with different number of users. Simulation results show that our proposed MHGphormer achieves a higher system sum-rate when compared with the homogeneous graph neural network, unsupervised deep neural network, and alternating optimization baseline algorithms.

关键词： Heterogeneous graph neural networks multiuser multiple-input multiple-output reconfigurable intelligent surface spectrum allocation terahertz communication Heterogeneous graph neural networks multiuser multiple-input multiple-output reconfigurable intelligent surface spectrum allocation terahertz communication

来源：评论

学校读者我要写书评

暂无评论

Robust transmission design for active IRS-aided multiuser MIMO cognitive radio systems with non-linear energy harvesting models

引用

TELECOMMUNICATION SYSTEMS 2024年第1期86卷 155-171页

作者： Quyet, Pham Van Kha, Ha Hoang Ho Chi Minh City Univ Technol HCMUT 268 Ly Thuong Kiet St Dist 10 Ho Chi Minh City Vietnam Vietnam Natl Univ Ho Chi Minh City Linh Trung Ward Ho Chi Minh City Vietnam

This paper studies a multiuser multiple-input multiple-output simultaneous wireless information and power transfer cognitive radio system with the aid of an active intelligent reflecting surface (IRS). Considering the scenario that nonlinear energy harvesting models and power splitting (PS) protocols are adopted at energy receivers and that channel state information (CSI) imperfections of the channels to the primary users (PUs) are taken into consideration, we aim at designing the secondary base station (SBS) transmit precoding matrices, the IRS reflection coefficient matrix, and the secondary user (SU) PS ratios. The design objective is to maximize the system sum-rate (SR) under the transmit power constraints at the SBS, amplification power constraints at the IRS, amplitude constraints on IRS reflection elements, robust interference power (IP) constraints at the PUs, and minimum harvested energy constraints at the SUs. The formulated optimization problem is intractable to directly solve since the design variables are nonlinearly coupled, the objective function and constraints are highly nonconvex, and robust IP constraints are semi-infinite. To tackle the mathematical challenges, we derive the amenable surrogate functions and constraints while to handle the semi-infinite robust IP constraints, we transform them into linear matrix inequalities. Then, to find optimized solutions to the considered design problem, we exploit alternating optimization frames to derive an efficient iterative algorithm (IA). The convergence and computational complexity of the developed IA are shown. Simulation results illustrate the performance gains of the designed problem and robustness of IP constraints against CSI imperfections. Additionally, the numerical results show that the active IRS-aided systems exhibit superior SR performance over the passive IRS-aided systems.

关键词： Intelligent reflecting surfaces multiuser multiple-input multiple-output Simultaneous wireless information and power transfer Non-linear energy harvesting Robust design

来源：评论

学校读者我要写书评

暂无评论

A Framework for Energy Efficiency Optimization in IRS-Aided Hybrid MU-MIMO Systems

引用

IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2025年第3期43卷 883-898页

作者： Ju, Xin Liu, Heng Gong, Shiqi Xing, Chengwen Zhao, Nan Niyato, Dusit Beijing Inst Technol Sch Informat & Elect Beijing 100081 Peoples R China Beijing Inst Technol Sch Cyberspace Sci & Technol Beijing 100081 Peoples R China Dalian Univ Technol Sch Informat & Commun Engn Dalian 116024 Peoples R China Nanyang Technol Univ Coll Comp & Data Sci Singapore Singapore

Energy efficiency (EE) optimization has attracted significant research attention for implementing green communications. With cost-effective and low-power advantages, intelligent reflecting surface (IRS) and hybrid analog-digital transceiver have recently emerged as two promising technologies of next-generation green wireless systems. In this paper, we propose a comprehensive framework for EE optimization in four types of IRS-aided hybrid analog-digital multiuser multiple-input multiple-output communication systems, including the uplink (UL) systems under the sum power and box eigenvalue constraints as well as the per-radio-frequency chain power constraints (PRPCs), and the downlink (DL) systems under the sum power constraint and the PRPCs. This framework proposes a unified design methodology to these four considered systems by separating the optimization of analog and digital matrix variables. Specifically, for the UL EE maximization problems, we firstly propose a channel alignment based algorithm to separately optimize the analog precoders at users, the analog combiner at the base station and the IRS reflecting matrix, whose computational complexity is significantly reduced as compared with the traditional alternating optimization algorithm. Then, by introducing the auxiliary variables and exploiting the Karush-Kuhn-Tucker conditions based algorithm, the optimal digital precoders at users are obtained in closed forms. Furthermore, the intractable DL EE optimization can be equivalently transformed into its virtual UL counterpart using the DL-UL duality, leading to the general applicability of the proposed framework. Extensive simulations reveal that the proposed algorithm attains the almost identical EE performance to the traditional benchmarks with a lower computational complexity.

关键词： Optimization Radio frequency Analog-digital conversion Transceivers Ink Hybrid power systems Linear programming Approximation algorithms Massive MIMO Eigenvalues and eigenfunctions Energy efficiency duality hybrid analog-digital system intelligent reflecting surface multiuser multiple-input multiple-output

来源：评论

学校读者我要写书评

暂无评论

Designing an Improved multiuser MIMO Framework using Enhanced Transmission Adoptions 2

Designing an Improved Multiuser MIMO Framework using Enhance...

引用

2nd International Conference on Automation, Computing and Renewable Systems, ICACRS 2023

作者： Mallikarjun, M. Sai Kiran, M.P.V.N. Vivek, T. Kavitha Electronics and Communication Engineering Vel Tech Rangarajan Dr.Sagunthala R&D Institute of Science and Technology Chennai India

ISBN: (纸本)9798350340235

The design of multiuser multiple-input multiple-output systems are of utmost importance to meet the increasing demands of modern wireless communication networks. This abstract highlight the key elements of multiuser MIMO system design, underscoring its significance in optimizing data rates, spectral efficiency, and overall wireless communication performance. multiuser MIMO exploits spatial diversity and multiplexing gains to enhance the system capabilities. It tackles challenges such as interference management, resource allocation, and user scheduling through advanced techniques like Zero-Forcing Beamforming and Dirty Paper Coding along with Maximum Ratio Transmission (MRT) and Alamouti Coding. The role of Channel State Information (CSI) acquisition in design decisions is discussed, emphasizing the trade-offs between the amount of feedback required and system performance. Additionally, practical considerations, including hardware limitations and signal processing complexity, are examined. The abstract also delves into the application of multiuser MIMO in emerging technologies like 5G and beyond, where Massive MIMO and advanced techniques like beamforming play pivotal roles in shaping the future of wireless communication. © 2023 IEEE.

关键词： Channel State Information (CSI) acquisition Dirty Paper Coding multiuser multiple-input multiple-output Zero-Forcing Beamforming

来源：评论

学校读者我要写书评

暂无评论

Joint Receive Antenna Selection and Beamforming in RIS-Aided MIMO Systems 59

Joint Receive Antenna Selection and Beamforming in RIS-Aided...

引用

59th Annual IEEE International Conference on Communications (IEEE ICC)

作者： Ouyang, Chongjun Bereyhi, Ali Asaad, Saba Liu, Yuanwei Zhang, Xingqi Mueller, Ralf R. Univ Coll Dublin Dublin Ireland Univ Toronto Toronto ON Canada York Univ N York ON Canada Queen Mary Univ London London England Univ Alberta Edmonton AB Canada Friedrich Alexander Univ Erlangen Nurnberg Erlangen Germany

ISBN: (纸本)9781728190549

This work studies a low-complexity design for reconfigurable intelligent surface (RIS)-aided multiuser multiple-input multiple-output systems. The base station (BS) applies receive antenna selection to connect a subset of its antennas to the available radio frequency chains. For this setting, the BS switching network, uplink precoders, and RIS phase-shifts are jointly designed, such that the uplink sum-rate is maximized. The principle design problem reduces to an NP-hard mixed-integer optimization. We hence invoke the weighted minimum mean squared error technique and the penalty dual decomposition method to develop a tractable iterative algorithm that approximates the optimal design effectively. Our numerical investigations verify the efficiency of the proposed algorithm and its superior performance as compared with the benchmark.

关键词： multiuser multiple-input multiple-output receive antenna selection reconfigurable intelligent surfaces

来源：评论

学校读者我要写书评

暂无评论

Exploiting Lens Antenna Arrays in Uplink mmWave MU-MIMO Networks: Joint Beamforming Optimization

Exploiting Lens Antenna Arrays in Uplink mmWave MU-MIMO Netw...

引用

International Symposium on Wireless Communication Systems (ISWCS)

作者： Ouyang, Chongjun Xu, Hao Zang, Xujie Yang, Hongwen Beijing Univ Posts & Telecommun Sch Informat & Commun Engn Beijing 100876 Peoples R China

ISBN: (数字)9781665455442

ISBN: (纸本)9781665455442

This paper considers a lens antenna array-assisted millimeter wave (mmWave) multiuser multiple-input multiple-output (MU-MIMO) system. The base station's beam selection matrix and user terminals' phase-only beamformers are jointly designed with the aim of maximizing the uplink sum rate. In order to deal with the formulated mixed-integer optimization problem, a penalty dual decomposition (PDD)-based iterative algorithm is developed via capitalizing on the weighted minimum mean square error (WMMSE), block coordinate descent (BCD), and minorization-maximization (MM) techniques. Moreover, a low-complexity sequential optimization (SO)-based algorithm is proposed at the cost of a slight sum rate performance loss. Numerical results demonstrate that the proposed methods can achieve higher sum rates than state-of-the-art methods.

关键词： Beam selection millimeter wave multiuser multiple-input multiple-output phase-only beamforming

来源：评论

学校读者我要写书评

暂无评论

Is NOMA Efficient in Multi-Antenna Networks? A Critical Look at Next Generation multiple Access Techniques

IEEE OPEN JOURNAL OF THE COMMUNICATIONS SOCIETY

引用

IEEE OPEN JOURNAL OF THE COMMUNICATIONS SOCIETY 2021年 2卷 1310-1343页

作者： Clerckx, Bruno Mao, Yijie Schober, Robert Jorswieck, Eduard A. Love, David J. Yuan, Jinhong Hanzo, Lajos Li, Geoffrey Ye Larsson, Erik G. Caire, Giuseppe Imperial Coll London Dept Elect & Elect Engn London SW7 2AZ England Friedrich Alexander Univ Erlangen Nurnberg Inst Digital Commun D-91054 Erlangen Germany Tech Univ Carolo Wilhelmina Braunschweig Inst Commun Technol D-38106 Braunschweig Germany Purdue Univ Sch Elect & Comp Engn W Lafayette IN 47907 USA Univ New South Wales Sch Elect Engn & Telecommun Sydney NSW 2052 Australia Univ Southampton Sch Elect & Comp Sci Southampton SO17 1BJ Hants England Linkoping Univ Dept Elect Engn S-58183 Linkoping Sweden Tech Univ Berlin Fac Elect Engn & Comp Sci Commun & Informat Theory Grp D-10587 Berlin Germany

In the past few years, a large body of literature has been created on downlink Non-Orthogonal multiple Access (NOMA), employing superposition coding and Successive Interference Cancellation (SIC), in multi-antenna wireless networks. Furthermore, the benefits of NOMA over Orthogonal multiple Access (OMA) have been highlighted. In this paper, we take a critical and fresh look at the downlink Next Generation multiple Access (NGMA) literature. Instead of contrasting NOMA with OMA, we contrast NOMA with two other multiple access baselines. The first is conventional Multi-User Linear Precoding (MU-LP), as used in Space-Division multiple Access (SDMA) and multi-user multiple-input multiple-output (MIMO) in 4G and 5G. The second, called Rate-Splitting multiple Access (RSMA), is based on multi-antenna Rate-Splitting (RS). It is also a non-orthogonal transmission strategy relying on SIC developed in the past few years in parallel and independently from NOMA. We show that there is some confusion about the benefits of NOMA, and we dispel the associated misconceptions. First, we highlight why NOMA is inefficient in multi-antenna settings based on basic multiplexing gain analysis. We stress that the issue lies in how the NOMA literature, originally developed for single-antenna setups, has been hastily applied to multi-antenna setups, resulting in a misuse of spatial dimensions and therefore loss in multiplexing gains and rate. Second, we show that NOMA incurs a severe multiplexing gain loss despite an increased receiver complexity due to an inefficient use of SIC receivers. Third, we emphasize that much of the merits of NOMA are due to the constant comparison to OMA instead of comparing it to MU-LP and RS baselines. We then expose the pivotal design constraint that multi-antenna NOMA requires one user to fully decode the messages of the other users. This design constraint is responsible for the multiplexing gain erosion, rate and spectral efficiency loss, ineffectiveness to serve

关键词： multiple antennas downlink non-orthogonal multiple access superposition coding rate-splitting multiple access broadcast channel multiuser linear precoding multiuser multiple-input multiple-output space division multiple access next generation multiple access

来源：评论

学校读者我要写书评

暂无评论

On the Performance of Distortion-Aware Linear Receivers in Uplink Massive MIMO Systems 16

On the Performance of Distortion-Aware Linear Receivers in U...

引用

16th International Symposium on Wireless Communication Systems (ISWCS)

作者： Aghdam, Sina Rezaei Eriksson, Thomas Chalmers Univ Technol Dept Elect Engn Gothenburg Sweden

ISBN: (纸本)9781728125275

We consider the uplink of a single-cell multi-user multiple-input multiple-output (MU-MIMO) system in presence of nonlinear distortion at the users and the base station. Assuming orthogonal frequency-division multiplexing (OFDM) transmission, we leverage Bussgang's theorem to derive an equivalent linear model and we formulate a distortion-aware linear minimum mean squared error (LMMSE)-based receiver. The accuracy of the proposed equivalent linear model is verified via numerical experiments. Furthermore, our results reveal that the distortion-aware LMMSE receiver can compensate in part for the performance loss due to nonlinear distortion over MU-MIMO-OFDM uplink system.

关键词： multiuser multiple-input multiple-output uplink nonlinear power amplifier hardware impairments Bussgang's theorem and linear receiver

来源：评论

学校读者我要写书评

暂无评论

Linear precoding design for cognitive multiuser MIMO systems using a leakage-based approach

引用

INTERNATIONAL JOURNAL OF EMBEDDED SYSTEMS 2013年第3期5卷 158-165页

作者： Sun, Chuiqiang Ge, Jianhua Li, Jing Shi, Xiaoye Bao, Xinxin Xidian Univ State Key Lab Integrated Serv Networks 2 Taibai South Rd Xian 710071 Shaanxi Peoples R China

In this paper, we develop linear precoding schemes for cognitive radio (CR) multiuser multiple-input multiple-output (MU-MIMO) downlink systems. A secondary user base station (SBS) with multiple secondary users (SUs) sharing the primary user (PU) spectrum is considered. In the proposed scheme, the block diagonalisation (BD) algorithm is adopted to remove the co-channel interference from the SBS to the PU completely, and the matching weighted signal-to-leakage-and-noise ratio (SLNR) maximisation algorithm is proposed to mitigate interference between SUs. We also discuss the cases where the SBS has only partial channel information and the channel estimation with errors, respectively. The proposed scheme does not require a strict restriction on the number of transmit and receive antennas. Simulation results show that the proposed scheme can achieve high sum rate throughput with affordable complexity.

关键词： cognitive radio multiuser multiple-input multiple-output MU-MIMO block diagonalisation signal-to-leakage-and-noise ratio SLNR

来源：评论

学校读者我要写书评

暂无评论

Per-layer transmit and receive filters design for Tomlinson-Harashima precoding in multiuser MIMO systems

引用

中国科学：信息科学（英文版） 2012年第4期55卷 839-849页

作者： HUANG Min CHEN Xiang ZHOU ShiDong WANG Jing Department of Electronic Engineering Research Institute of Information TechnologyNational Laboratory for Information Science and Technology Tsinghua UniversityBeijing 100084 China

In this paper, the per-layer design for Tomlinson-Harashima precoding (THP) in the downlink of multiuser multiple-input multiple-output (MIMO) systems is investigated. In these systems, the number of the receivers is equal to that of the transmit antennas. Based on the criterion of maximum system sum-capacity, we study two per-layer joint transmit and receive filters design schemes with receive antenna beamforming (RAB) and receive antenna selection (RAS), respectively. Moreover, the differences of the equivalent channel gains and capacities between these two schemes are analyzed theoretically. Simulation results show that by these per-layer schemes, the system sum-rate is improved significantly with respect to the per-user processing scheme.

关键词： Tomlinson-Harashima precoding multiuser multiple-input multiple-output per-layer joint transmit and receive filters design

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：