检索结果-内蒙古大学图书馆

IEEE PHOTONICS JOURNAL 2022年第1期14卷 1页

作者： Chen, Chen Zeng, Lin Zhong, Xin Fu, Shu Liu, Min Du, Pengfei Chongqing Univ Sch Microelect & Commun Engn Chongqing 400044 Peoples R China A STAR Singapore Inst Mfg Technol Singapore 138634 Singapore

In this paper, we propose an orthogonal frequency division multiplexing (OFDM)-based generalized optical quadrature spatial modulation (GOQSM) technique for multiple-input multiple-output optical wireless communication (MIMO-OWC) systems. Considering the error propagation and noise amplification effects when applying maximum likelihood and maximum ratio combining (ML-MRC)-based detection, we further propose a deep neural network (DNN)-aided detection for OFDM-based GOQSM systems. The proposed DNN-aided detection scheme performs the GOQSM detection in a joint manner, which can efficiently eliminate the adverse effects of both error propagation and noise amplification. The obtained simulation results successfully verify the superiority of the deep learning-aided OFDM-based GOQSM technique for high-speed MIMO-OWC systems.

关键词： Light emitting diodes Optical transmitters Optical modulation Modulation High-speed optical techniques Adaptive optics Spatial indexes Optical wireless communication orthogonal frequency division multiplexing multiple-input multiple-output deep neural network

来源：评论

学校读者我要写书评

暂无评论

High-isolation eight-element MIMO array for unbroken metal-rimmed smartphone applications

引用

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING 2022年第12期32卷 e23404-e23404页

作者： Ren, Aidi Yang, Lixia Huang, Zhixiang Yu, Hong-wei Chen, Qian Liu, Ying Anhui Univ Informat Mat & Intelligent Sensing Lab Anhui Prov Hefei 230601 Peoples R China China Elect Technol Corp Res Inst 38 Hefei Peoples R China Xidian Univ Natl Key Lab Antennas & Microwave Technol Xian Peoples R China

ABSTARCT In this paper, a high-isolation eight-unit multiple-input multiple-output (MIMO) array is proposed, which applies to future smartphones with unbroken metal frames. Two types of elements (inverted H-shaped slot antenna [IHSA] and modified top-loaded monopole [MTLM]) are adopted to realize low mutual coupling, and the detailed decoupling mechanism is also presented. The IHSA with a better-reduced ground effect is utilized, which contributes to suppressing mutual coupling. To further enhance isolation, the MTLM without ground clearance is exploited, which cannot excite the radiated mode of the IHSA. To mitigate the effects of an unbroken metal frame, a shorting strip is introduced, which not only improves the impedance matching but also reduces the profile of the MTLM. Ultimately, the proposed MIMO system integrated with an unbroken metal frame is constituted by four IHSAs and four MTLMs, which offers a measured isolation of more than 20 dB. What's more, the calculated envelop correlation coefficients (ECCs) are less than 0.013.

关键词： 5G communication high isolation multiple-input multiple-output unbroken metal frame

来源：评论

学校读者我要写书评

暂无评论

Over-the-Air Federated Learning Over MIMO Channels: A Sparse-Coded multiplexing Approach

引用

IEEE Transactions on Wireless Communications 2025年

作者： Zhong, Chenxi Yang, Huiyuan Yuan, Xiaojun University of Electronic Science and Technology of China National Key Laboratory of Wireless Communications Chengdu China

The communication bottleneck of over-the-air federated learning (OA-FL) lies in aggregating the gradients of local learning models. In this paper, we study the reduction of the communication overhead in the gradient aggregation by using the multiple-input multiple-output (MIMO) technique. We propose a novel sparse-coded multiplexing (SCoM) approach that employs sparse-coding compression and MIMO multiplexing to balance the communication overhead and the learning performance of the FL model. We derive an upper bound on the learning performance loss of the SCoM-based MIMO OA-FL scheme by quantitatively characterizing the gradient aggregation error. Based on the analysis results, we show that the optimal number of multiplexed data streams to minimize the upper bound on the FL learning performance loss is given by the minimum of the numbers of transmit and receive antennas. We then formulate an optimization problem for the design of precoding and post-processing matrices to minimize the gradient aggregation error. To solve this problem, we develop an efficient algorithm based on alternating optimization (AO) and Karush-Kuhn-Tucker (KKT) conditions, which effectively mitigates the impact of the gradient aggregation error. Numerical results demonstrate the superb performance of the proposed SCoM approach. © 2002-2012 IEEE.

关键词： multiple-input multiple-output multiplexing Over-the-air federated learning turbo compressed sensing

来源：评论

学校读者我要写书评

暂无评论

Physical Layer Security Optimization for MIMO Enabled Visible Light Communication Networks

Physical Layer Security Optimization for MIMO Enabled Visibl...

引用

IEEE Global Communications Conference (GLOBECOM)

作者： Xu, Zheng Chen, Ming Chen, Mingzhe Yang, Zhaohui Cang, Yihan Poor, H. Vincent Southeast Univ Natl Mobile Commun Res Lab Nanjing Peoples R China Southeast Univ Sch Cyber Sci & Engn Nanjing Peoples R China UCL Dept Elect & Elect Engn London England Princeton Univ Dept Elect & Comp Engn Princeton NJ 08544 USA

ISBN: (纸本)9781728181042

This paper investigates the optimization of physical layer security in multiple-input multiple-output (MIMO) enabled visible light communication (VLC) networks. In the considered model, one transmitter equipped with light-emitting diodes (LEDs) intends to send confidential messages to legitimate users while one eavesdropper attempts to eavesdrop on the communication between the transmitter and legitimate users. This security problem is formulated as an optimization problem whose goal is to minimize the sum mean-square-error (MSE) of all legitimate users while meeting the MSE requirement of the eavesdropper thus ensuring the security. To solve this problem, the original optimization problem is first transformed to a convex problem using successive convex approximation. An iterative algorithm with low complexity is proposed to solve this optimization problem. Simulation results show that the proposed algorithm can reduce the sum MSE of legitimate users by up to 40% compared to a conventional zero forcing scheme.

关键词： Physical layer security visible light communication multiple-input multiple-output transceiver design

来源：评论

学校读者我要写书评

暂无评论

Demonstration of 144-Gbps Photonics-Assisted THz Wireless Transmission at 500 GHz Enabled by Joint DBN Equalizer

引用

MICROMACHINES 2022年第10期13卷 1617-1617页

作者： Liu, Xiang Zhang, Jiao Gao, Shuang Tong, Weidong Wang, Yunwu Lei, Mingzheng Hua, Bingchang Cai, Yuancheng Zou, Yucong Zhu, Min Southeast Univ Natl Mobile Commun Res Lab Nanjing 210096 Peoples R China Purple Mt Labs Nanjing 211111 Peoples R China

The THz wireless transmission system based on photonics has been a promising candidate for further 6G communication, which can provide hundreds of Gbps or even Tbps data capacity. In this paper, 144-Gbps dual polarization quadrature-phase-shift-keying (DP-QPSK) signal generation and transmission over a 20-km SSMF and 3-m wireless 2 x 2 multiple-input multiple-output (MIMO) link at 500 GHz have been demonstrated. To further compensate for the linear and nonlinear distortions during the fiber-wireless transmission, a novel joint Deep Belief Network (J-DBN) equalizer is proposed. Our proposed J-DBN-based schemes are mainly optimized based upon the constant modulus algorithm (CMA) and direct-detection least mean square (DD-LMS) equalization. The results indicate that the J-DBN equalizer has better bit error rate (BER) performance in receiver sensitivity. In addition, the computational complexity of the J-DBN-based equalizer can be approximately 46% lower than that of conventional equalizers with similar performance. To our knowledge, this is the first time that a novel joint DBN equalizer has been proposed based on classical algorithms. It is a promising scheme to meet the demands of future fiber-wireless integration communication for low power consumption, low cost, and high capacity.

关键词： Terahertz-band multiple-input multiple-output polarization multiplexing seamless integration Deep Belief Network

来源：评论

学校读者我要写书评

暂无评论

Recent Trends in Coherent Free-Space Optical Communications 4

Recent Trends in Coherent Free-Space Optical Communications

引用

Conference on Metro and Data Center Optical Networks and Short-Reach Links IV

作者： Zhang, Chao Uyama, Kota Zhang, Zheyuan Jin, Lei Set, Sze Yun Yamashita, Shinji Glick, Madeleine Srivastava, Atul K. Akasaka, Youichi Univ Tokyo Res Ctr Adv Sci & Technol Meguro Ku 4-6-1 Komaba Tokyo 1538904 Japan

ISBN: (数字)9781510642607

ISBN: (纸本)9781510642607

Free-space optical communication is a line-of-sight wireless communication scheme, which is preferred for its number of prime advantages over radio frequency wireless communication, such as no spectrum licensing, large bandwidth, inherent security, electromagnetic compatibility/electromagnetic interference immunity etc. Moreover, free-space optical communication also benefits from low-cost installation and maintenance. It has been studied for the next generation access networks, inter-building connections, ground-to-unmanned aerial vehicle links, underwater communication applications, inter-satellite links, deep space links etc. Among various detection approaches utilized in free-space optical communication, coherent detection can achieve the best sensitivity in a bandwidth-limited condition, effectively demodulate optical multilevel coded signals to attain high spectral e i-ciency, offer excellent background noise rejection. However, such an attractive free-space optical communication suffer from waveform distortion, scintillation, phase fluctuations etc. after transmission in atmospheric channels. Its link losses are almost dependent on atmospheric effects and climatic conditions. In this article, we present an up-to-date survey on coherent free-space optical communication, the atmospheric turbulent effects especially the impacts of turbulence in free-space optical links, and countermeasures against such impairments.

关键词： 6G free-space optical communication atmospheric turbulence scintillation wavefront distortion coherent detection thresholding multiple-input multiple-output space-time block coding adaptive optics relay latency

来源：评论

学校读者我要写书评

暂无评论

COMPACT RECONFIGURABLE POLARIZATION PLASMA SQUARE MICROSTRIP PATCH MIMO ANTENNA FOR 5G WIRELESS APPLICATIONS 38

COMPACT RECONFIGURABLE POLARIZATION PLASMA SQUARE MICROSTRIP...

引用

38th National Radio Science Conference (NRSC)

作者： Elgiddawy, Sarah Malhat, Hend A. Zainud-Deen, Saber H. Ibrahim, Ahmed A. Hamed, Hisham Minia Univ Fac Engn Al Minya Egypt Menoufia Univ Fac Elect Engn Shibin Al Kawm Al Minufiyah Egypt Badr Univ Cairo Fac Engn & Technol Badr City Egypt

ISBN: (纸本)9781665418577

This paper proposes a reconfigurable polarization square microstrip patch antenna (SMSPA) using plasma and its multiple-input multiple-output (MIMO) for 5G wireless networks. The SMSPA has two square etched boxes with asymmetric length and positions from the SMSPA center along its diagonal. The single antenna has an overall size of 96 mm x 96 mm x 4.6 mm (0.78 lambda x 0.78 lambda x 0.0377 lambda). The two square boxes length and position are optimized for achieving minimum axial-ratio of 0.608 dB dB at 2.44 GHz. Four polarization cases are achieved, case (1) and case (2) for left-hand and right-hand circular polarization (CP), while case (3) and case (4) for linear polarization. The overall dimensions of the proposed 4-port (2X2) MIMO antenna are 160 mm x 160 mm x 4.6 mm. The proposed MIMO antenna layout guarantee compact size with spacing distance 0.25 lamda (30.5 mm) between MIMO elements with isolation higher than 22.44 dB and an envelope correlation coefficient ECC lower than 0.015 between elements.

关键词： Reconfigurable Antenna microstrip patch antenna Circular Polarization multiple-input multiple-output MIMO

来源：评论

学校读者我要写书评

暂无评论

Genetic Optimization of Liquid Crystal Matrix Based Interference Suppression for VLC MIMO Transmissions

IEEE PHOTONICS JOURNAL

引用

IEEE PHOTONICS JOURNAL 2022年第1期14卷 1页

作者： Krohn, Adrian Pachnicke, Stephan Hoeher, Peter Univ Kiel Commun D-24143 Kiel Germany Univ Kiel Informat & Coding D-24143 Kiel Germany

Optical channel decorrelation is a key aspect in designing a multi-user visible light communication system. As light-emitting diodes (LEDs) are commonly used for illumination and data transmission in such a system simultaneously, the interference between them is a major problem for suitable modulation schemes. We have proposed to position liquid-crystal (LC) matrix elements in front of the receivers in order to block unwanted light - so effectively acting as filter and reducing the interference. To do so, the appropriate pixels of the LC filter are switched either to a transmissive state or to an opaque state. The selection of the correct pixel patterns is a high-order optimization problem, which makes it challenging for classic algorithms. In this paper, we suggest applying a genetic optimization to find suitable pixel patterns. We combine this kind of receiver-side optimization with conventional convex precoding at the transmitter side in an iterative manner. The overall optimization goal is to maximize the sum rate over all users. To prove the effectiveness, we use a numeric ray-tracing simulation with different settings. Also we analyze the impact of the main parameters for the genetic algorithm.

关键词： Optimization Precoding Receivers Genetics Lighting Reflection Light sources Visible light communication optical communication free-space optical communication multiple-input multiple-output

来源：评论

学校读者我要写书评

暂无评论

A Low-Complexity Algorithm for a Reinforcement Learning-Based Channel Estimator for MIMO Systems

引用

SENSORS 2022年第12期22卷 4379-4379页

作者： Kim, Tae-Kyoung Min, Moonsik Gachon Univ Dept Elect Engn Seongnam 13120 South Korea Kyungpook Natl Univ Sch Elect Engn Daegu 41566 South Korea Kyungpook Natl Univ Sch Elect & Elect Engn Daegu 41566 South Korea

This paper proposes a low-complexity algorithm for a reinforcement learning-based channel estimator for multiple-input multiple-output systems. The proposed channel estimator utilizes detected symbols to reduce the channel estimation error. However, the detected data symbols may include errors at the receiver owing to the characteristics of the wireless channels. Thus, the detected data symbols are selectively used as additional pilot symbols. To this end, a Markov decision process (MDP) problem is defined to optimize the selection of the detected data symbols. Subsequently, a reinforcement learning algorithm is developed to solve the MDP problem with computational efficiency. The developed algorithm derives the optimal policy in a closed form by introducing backup samples and data subblocks, to reduce latency and complexity. Simulations are conducted, and the results show that the proposed channel estimator significantly reduces the minimum-mean square error of the channel estimates, thus improving the block error rate compared to the conventional channel estimation.

关键词： multiple-input multiple-output channel estimation Markov decision process reinforcement learning

来源：评论

学校读者我要写书评

暂无评论

An electrically small 4-port self-decoupled MIMO antenna pairs operating in n78 5G NR band for smartphone applications

引用

AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 2022年 145卷

作者： Moses, Abi T. Zerith Moses, Nesasudha Janapala, Doondi Kumar Karunya Inst Technol & Sci Dept Elect & Commun Engn Coimbatore India

In this article, a 4-port electrically small multiple-input multiple-output (MIMO) antenna system functioning in 5G n78 band for the future smartphone implementation is recommended. The system includes two antenna pairs that are positioned in the exact centers of the vertical edges of the smartphone system. The overall size of each antenna pair is only 23.5 x 5.2 mm2. The reduction is size is obtained by connecting the two radiators, and the antenna pair is excited by coaxial feeding technique. A very good and acceptable isolation amid the antenna elements are accomplished by inserting a T-shaped structure, and is further enhanced with the addition of a reflector at the backside of the radiator. The self-isolated MIMO system operates in the n78 sub-6 GHz band (3.4-3.6 GHz) of the 5G Frequency Range 1 (FR1), with worst case isolation of -17.5 dB between the antennas in the same block in the entire band of operation. The evolution analysis to acquire the proposed structure and parametric study of some ideal parameters are carried out to get a superior insight of the operating principle of the proposed structure. Various MIMO diversity parameters such as Envelope Correlation Coefficient (ECC), Channel Capacity Loss (CCL), Total Active Reflection Coefficient (TARC), Diversity Gain (DG), and Mean Effective Gain (MEG) of the MIMO system are measured and compared with the calculated values. The ECC value is <0.009 in the whole essential operating band, the poorest being between Ant.1 and Ant. 2. A model of the designed smartphone MIMO system is fabricated and experimentally verified, with acceptable coherence between the simulated and the measured results. The MIMO system has a total efficiency and peak gain over 74% and 4.53 dBi correspondingly in the complete operating bandwidth, making it a suitable contender for the future 5G smartphone application. Likewise, the effect of user hand on the S-Parameters and antenna pattern are studied and acceptable results are obtained

关键词： Self-decoupled multiple-input multiple-output Isolation Smartphone User-hand impact n78 band

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：