检索结果-内蒙古大学图书馆

Particle swarm optimization assisted B-spline neural network based predistorter design to enable transmit precoding for nonlinear MIMO downlink

引用

NEUROCOMPUTING 2021年 458卷 336-348页

作者： Chen, Sheng Ng, Soon Xin Khalaf, Emad Morfeq, Ali Alotaibi, Naif Univ Southampton Sch Elect & Comp Sci Southampton SO17 1BJ Hants England King Abdulaziz Univ Elect & Comp Engn Dept Fac Engn Jeddah 21589 Saudi Arabia

For the multiple-input multiple-output (MIMO) downlink employing high-order quadrature amplitude modulation signaling and with nonlinear high power amplifiers (HPAs) at base station transmitter, the existing precoding designs relying on the linear MIMO channel can no longer work. We propose an effi-cient and accurate predistorter design to enable transmit precoding for nonlinear MIMO downlink. Specifically, we obtain the closed-form least squares estimates of the nonlinear HPA's amplitude and phase response using two B-spline neural networks during training. The estimated HPA's phase response automatically yields the estimate of the predistorter's phase response. Based on the B-spline neural net-work estimate of the HPA's amplitude response, we construct a B-spline neural network model for the predistorter amplitude response, and we adopt a particle swarm optimization (PSO) algorithm to solve this highly nonlinear optimization problem. Using our accurate predistorter estimate to pre-compensate for the nonlinear distortions of the transmit HPAs, a standard full-digital transmit precoding design can readily be adopted to combat the MIMO channel interference. A simulation study is conducted to demonstrate the effectiveness of our proposed PSO assisted predistorter design. (c) 2021 Elsevier B.V. All rights reserved.

关键词： Particle swarm optimization B-spline neural network Nonlinear inversion Nonlinear high power amplifier Predistorter multi-input multi-output Downlink precoding

来源：评论

学校读者我要写书评

暂无评论

Swept-sine integration method for complex amplitude extraction of swept-sine signal

引用

JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY 2020年第12期34卷 4981-4988页

作者： Zheng, Wei Cui, Xuli Chen, Huaihai Zheng, Ronghui Nanjing Univ Aeronaut & Astronaut State Key Lab Mech & Control Mech Struct Nanjing Jiangsu Peoples R China BSH Elect Appliances Co Ltd Jiangsu Nanjing Jiangsu Peoples R China

Swept-sine vibration test plays a significant role in product validations. As its basic step, the accuracy and efficiency of complex amplitude (which includes the amplitude and phase information of swept-sine signal) extraction have an important impact on the performance of swept-sine vibration test. In order to improve the efficiency while ensuring its accuracy, a swept-sine integration method is proposed. The proposed swept-sine integration method, which is inspired by tracking filter method and tracking integration method, utilizes a weighted integral process to extract the complex amplitude. A numeral example is presented to compare the performance of the proposed method with several other methods for complex amplitude extraction which are also reviewed in this paper. By comparing the results of the numerical example, some light is shed on the strength of the method proposed. Afterwards, the swept-sine integration method is applied in a real test, further validating the appliance value of this method.

关键词： Complex amplitude extraction Hilbert transform multi-input multi-output Swept-sine vibration Tracking filter

来源：评论

学校读者我要写书评

暂无评论

Joint Frequency Offset and Channel Estimation for MIMO Systems in the Presence of Timing Error

引用

CIRCUITS SYSTEMS AND SIGNAL PROCESSING 2010年第2期29卷 275-293页

作者： Dong, Wei Li, Jiandong Lu, Zhuo Zhang, Wen Xidian Univ Broadband Wireless Commun Lab Inst Informat Sci State Key Lab Integrated Serv Networks Xian 710071 Peoples R China

This paper deals with the problem of joint frequency offset (FO) and channel estimation for multi-input multi-output (MIMO) systems in the presence of a timing error. Two equivalent signal models with FO and a timing error are given, and then a joint estimation method is derived. The proposed estimation method consists of two steps. Firstly, a maximum likelihood (ML) FO estimator is proposed based on the second signal model. Secondly, based on the FO estimate, we formulate the timing error and channel estimation as a problem of composite hypothesis testing according to the first signal model, and then solve the problem using a composite hypothesis testing approach. Simulation results are performed to show the effectiveness of the proposed method.

关键词： multi-input multi-output Frequency offset estimation Channel estimation Timing error

来源：评论

学校读者我要写书评

暂无评论

Hierarchical BEM Based Channel Estimation With Very Low Pilot Overhead for High Mobility MIMO-OFDM Systems

引用

IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2022年第10期71卷 10543-10558页

作者： Zhang, Yanfeng Zhu, Xu Liu, Yujie Jiang, Yufei Guan, Yong Liang Lau, Vincent K. N. Harbin Inst Technol Sch Elect & Informat Engn Shenzhen Peoples R China Nanyang Technol Univ Continental NTU Corp Lab Singapore 639798 Singapore Hong Kong Univ Sci & Technol Dept Elect & Comp Engn Hong Kong Peoples R China

Channel estimation for multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) systems is a challenging issue in high mobility scenarios due to prohibitive pilot overhead and complexity. In this paper, a hierarchical basis expansion model (BEM) based channel estimation scheme is proposed for doubly selective channels, which requires a low pilot overhead and computational complexity. A mixed-BEM is proposed for time-varying channels alongside a complex exponential-BEM (CE-BEM), resulting in very few unknown parameters required for channel estimation. Based on the hierarchical BEM structure, an analytical channel estimation model is derived. By employing the block-structured sparsity and a small number of mixed-BEM coefficients in the antenna-time-BEM domain, a low-complexity estimator is proposed to recover the mixed-BEM coefficients accurately. The lower bound on the mean square error (MSE) of channel estimation is derived to verify the effectiveness of the proposed scheme. Simulation results show that the proposed channel estimation scheme significantly outperforms the existing methods in terms of MSE of channel estimation and bit error rate, with much lower pilot overhead and computational complexity.

关键词： Channel estimation Symbols OFDM Estimation Doppler effect Computational modeling Time-domain analysis Channel estimation basis expansion model multi-input multi-output orthogonal frequency division multiplexing sparse recovery

来源：评论

学校读者我要写书评

暂无评论

MIMO-employed coherent photonic-radar (MIMO-Co-PHRAD) for detection and ranging

引用

WIRELESS NETWORKS 2021年第4期27卷 2549-2558页

作者： Sharma, Vishal Kbashi, Hani J. Sergeyev, Sergey Aston Univ Sch Engn & Appl Sci Birmingham B4 7ET W Midlands England

Recently, the photonics-radar technology comes out as an attractive candidate in the arena of smart autonomous transportation, surveillance, and navigation-related applications owing to provide wide-spectra to attain improved and precise radar-resolutions. On the other hand, microwave radars, due to limited bandwidth, are incapable of coping with the demands of next-generation radar technology. Moreover, the atmospheric fluctuations become more prominent at higher frequencies and affect the radar's performance significantly. Subsequently, the authors develop a 2 x 2 multi-input multi-output (MIMO) employed linear frequency-modulated continuous-wave coherent photonic-radar system (MIMO-Co-PHRAD) using OptiSystem (TM) and MATLAB (TM) to attain a prolonged detection-range with an enhanced visibility. The developed MIMO-Co-PHRAD is investigated with heterodyne- and homodyne-detection approaches under weak-to-strong regimes of the atmospheric fluctuations like Rain and Fog. A comparison is also drawn for both the demonstrated MIMO-equipped laser-driven coherent photonic-radar systems. The performance of both the developed MIMO-Co-PHRAD systems is evaluated by measuring the intensity of reflected-echoes, signal-to-noise ratio, and range-Doppler patterns. A contrast with the single-input single-output coherent photonic-radar (SISO-Co-PHRAD) is also established to validate the robustness of the demonstrated MIMO-Co-PHRAD.

关键词： Photonic-radar Coherent detection multi-input multi-output Fog Rain

来源：评论

学校读者我要写书评

暂无评论

An Efficient Hierarchical User Grouping and Successive Group Search Approximation Based Beam-Forming Method for IRS-Aided Millimeter-Wave Networks with NOMA

引用

WIRELESS PERSONAL COMMUNICATIONS 2024年第1期138卷 171-188页

作者： Ramakrishna, Alajangi Kumari, K. Karuna GITAM Dept EECE Visakhapatnam 530041 Andhra Pradesh India GITAM Visakhapatnam 530045 Andhra Pradesh India

The combination of non-orthogonal multiple access (NOMA) and intelligent reflective surface (IRS) is an efficient solution to significantly increase the energy efficiency of the wireless communication system. This paper considers a downlink IRS-based Millimeter wave (mmWave) massive multiple-input multiple-output (MIMO)-NOMA system. In this work, a two-layer hierarchical AGglomerative NESting- DIvisie ANAlysis Clustering Algorithm (AGNES-DIANA) user grouping (2L-HAD-UG) is proposed to group users. In the proposed 2L-HAD-UG, the first layer will use the AGNES algorithm to efficiently group the users into different clusters. After the first level of clustering, some user groups are larger than others, and perhaps some users with weakly correlated channels are assigned to the same groups. To address these concerns, the large user groups are divided into several smaller groups, and each user whose channels are weakly correlated is isolated as a separate group. In the second layer, the DIANA Hierarchical Clustering is used to divide the larger clusters based on the channel correlation value. After user grouping, a new joint active and passive beam-forming design problem is formulated to maximize the achievable rate of each user in each cluster under the Quality of Service (QoS) requirements of other users, the conditions of Successive Interference Cancellation (SIC) decoding rate, the constraints of IRS reflection components and the transmission power restrictions. The formulated optimization problem is solved by proposing a new Successive Chaotic Group Search Approximation (SCGSA) algorithm. With the proposed massive mmWave MIMO-NOMA system, the spectral efficiency, energy efficiency, and sum rate are achieved to 18.56 bits per second (bps)/Hertz (Hz), 57.56 bps/Hz/Watt (W) and 21.58 bps/Hz, respectively.

关键词： Massive mmWave Non-orthogonal multiple access multi-input multi-output User grouping Clustering Hybrid beam-forming Successive Chaotic group search approximation

来源：评论

学校读者我要写书评

暂无评论

An iterative LMI approach for H_∞ synthesis of multivariable PI/PD controllers for stable and unstable processes

引用

CHEMICAL ENGINEERING RESEARCH & DESIGN 2018年 132卷 606-615页

作者： Merrikh-Bayat, Farshad Univ Zanjan Dept Elect & Comp Engn Zanjan Iran

An iterative linear matrix inequality (LMI) approach for designing multi-input multi-output (MIMO) PI/PD controller for stable/unstable multivariable processes is proposed in this paper. For this purpose, the matrix gains of controller are calculated such that the closed-loop system be stable, and simultaneously, the infinity norm of the weighted sensitivity function is minimized. This problem is mathematically formulated using the well-known bounded real lemma (BRL). The matrix inequality of the BRL is nonlinear because of multiplication of the variable of Lyapunov equation and gains of controller. To remove this nonlinearity, first a solution to the Lyapunov LMI is calculated using some necessary-type LMIs developed for this purpose. Then, this solution is substituted in the BRL to arrive at an LMI whose solution determines the gains of a stabilizing MIMO PI/PD controller which also minimizes the infinity norm of the weighted sensitivity function. If the resulting controller was not satisfactory, one can use the proposed iterative algorithm to improve its performance. The proposed method is used for tuning MIMO PI/PD for four stable/unstable MIMO processes. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

关键词： Bounded real lemma H-infinity control PID tuning multivariable process multi-input multi-output

来源：评论

学校读者我要写书评

暂无评论

Hybrid Precoding Design for MIMO System With One-Bit ADC Receivers

引用

IEEE ACCESS 2018年 6卷 48478-48488页

作者： Hou, Qitong Wang, Rui Liu, Erwu Yan, Dongliang Tongji Univ Sch Elect & Informat Engn Shanghai 201804 Peoples R China Xidian Univ State Key Lab Integrated Serv Networks Xian 710071 Shaanxi Peoples R China

When wireless transmission is performed over the bandwidth in the order of a gigahertz, high-resolution analog-to-digital converters (ADCs), and the large number of radio frequency chains significantly increase the power consumption. To address this issue, one promising technique is to use low-resolution, even one-bit ADCs. Another promising technique is to apply a hybrid precoding architecture to reduce the number of RF chains. In this paper, we propose to combine those techniques to reduce the hardware costs in multi-input multi-output system. Our objective is to optimize the hybrid precoder with the aim of increasing the achievable rate. To this end, we first derive an expression for the achievable rate in flat fading channels based on the Bussgang theorem, which is able to reformulate the nonlinear quantitative process as a linear function with identical first- and second-order statistics. To solve the non-convex hybrid precoding design problem, we treat the hybrid precoding design as a matrix factorization problem, which can be solved with an efficient alternating minimization algorithm. That is, we solve the digital precoder and the analog precoder in an alternative way in two separate subproblems. To find the optimal precoder in the first subproblem, we first prove the optimal structure of the digital precoding matrix. With it, we transfer the digital precoding design to a power allocation problem, the closed-form solution of which is then optimally found by using Karush-Kuhn-Tucker conditions. In the second subproblem, due to the non-convex modulus-norm constraint, it is challenging to directly solve the analog precoder. To resolve this problem, we propose to optimize the phases in the analog precoding matrix and adopt the subgradient algorithm to find the local optimal solution. Our simulation results show that the proposed hybrid precoding design effectively improves the achievable rates.

关键词： multi-input multi-output analog-to-digital converter one-bit quantization hybrid precoding alternating minimization

来源：评论

学校读者我要写书评

暂无评论

Optimization of Energy Consumption in the MEC-Assisted multi-User FD-SWIPT System

引用

IEEE ACCESS 2020年 8卷 21345-21354页

作者： Fu, Jiafei Hua, Jingyu Wen, Jiangang Chen, Hao Lu, Weidang Li, Jiamin Zhejiang Gongshang Univ Sch Informat & Elect Engn Hangzhou 310018 Peoples R China Zhejiang Univ Technol Coll Informat Engn Hangzhou 310023 Peoples R China Southeast Univ Natl Commun Res Lab Nanjing 210096 Peoples R China

That alleviating the heavy computing task, improving spectral efficiency and prolonging battery lifetime have been the key design challenges in Internet of Things (IoT) and intelligent connected vehicles (ICV). This paper studies the optimization of communication, computation and energy resource to minimize the energy consumption in the mobile terminal, where some superior technologies are included, such as Full-Duplex (FD), Simultaneous Wireless Information and Power Transfer (SWIPT), Mobile-Edge Computing (MEC) and multi-input multi-output (MIMO). In this model, the MEC-assisted Base station (BS) works in FD mode, then it can transmit and receive signals in the same frequency and time. Moreover, the mobile devices offload some computation tasks to the BS and complete local computations at the same time. Besides, the mobile device harvests the energy from the BS to support its energy consumption. And, our target is to minimize the energy consumption of mobile devices. Since the problem is non-convex, we propose an iterative solving algorithm including a multi-step optimization. First, we obtain the closed-form solution of the CPU frequency. And then, we transform the remain problem into a convex one to solve it by the interior point algorithm. Finally, we obtain the approximate solution by multiple iterations. Simulation results show that the proposed algorithm is superior to the compared schemes.

关键词： Mobile-edge computing simultaneous wireless information and power transfer multi-input multi-output full-duplex multi-step iteration vehicular communications

来源：评论

学校读者我要写书评

暂无评论

THE DESIGN OF A LTE/MIMO ANTENNA WITH HIGH ISOLATION USING A DECOUPLING NETWORK

引用

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2014年第9期56卷 2187-2191页

作者： Baek, Jisoo Choi, Jaehoon Hanyang Univ Dept Elect & Comp Engn Seoul 133791 South Korea

A multi-input multi-output (MIMO) antenna with high isolation using a decoupling network for long term evolution (LTE) services is proposed. To improve the isolation, a decoupling network consisting of two sections of a transmission line is placed at the center of two radiating elements. The isolation was enhanced by approximately 23 dB comparing to that without a decoupling network. The fabricated MIMO antenna satisfies a 6-dB return loss requirement and the envelope correlation coefficient is maintained below 0.4 over the LTE band 13 ranging from 746 to 787 MHz. The proposed antenna shows a low specific absorption rate value to meet regulations over the frequency band of interest. (C) 2014 Wiley Periodicals, Inc.

关键词： decoupling network isolation multi-input multi-output long term evolution mobile antennas

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：