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8th IEEE MTT-S International Wireless Symposium (IWS) part of China Microwave Week

作者： Wang, Keyi Liao, Guisheng Xu, Jingwei Tong, Fei Lan, Lan Xidian Univ Natl Lab Radar Signal Proc Xian 710071 Peoples R China

ISBN: (纸本)9781665435277

In recent years, frequency diverse array (FDA) with multiple-input multiple-output (MIMO) technique, which is referred to as FDA-MIMO radar, has attracted extensive attentions due to its outstanding advantages of introducing additional controllable degrees-of-freedom (DOFs) in range dimension. For FDA-MIMO radar mounted on a moving platform, one big concern is clutter rank. This paper derives the analytical expression of clutter rank in FDA-MIMO radar with range ambiguity. The clutter rank is studied based on subspace transformation and the correlation of vectors in the transformed subspace is explored. Then the maximum resolvable number of range ambiguity can be determined. Simulation results have verified the effectiveness of the proposed method.

关键词： frequency diverse array multiple-input multiple-output clutter rank range ambiguity

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Gap Analysis of VLC-MIMO Capacity Lower Bound with Different Signal Distributions 17

Gap Analysis of VLC-MIMO Capacity Lower Bound with Different...

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17th IEEE International Wireless Communications and Mobile Computing Conference (IEEE IWCMC)

作者： Wang, Xiaoqian Liang, Xia Yuan, Yifei Dong, Jing Wang, Hanning Wang, Qixing China Mobile Res Inst Beijing Peoples R China

ISBN: (纸本)9781728186160

Visible light communication (VLC) multiple-input multiple-output (MIMO) technology is a promising technology in 6G. However, the existing capacity formulae for radio frequency (RF) cannot be directly used for VLC due to the constraints of transmitted signals and unique channel characteristics. In this paper, we make a comparison of different signal distribution. Firstly, we analyze the relationship between transmitted and received signals based on zonotopes model. Then the capacity gap between the truncated Gaussian distribution and uniform distribution is analyzed. Simulations show that the uniform distribution has a better performance than truncated Gaussian, which may promote new signal design for VLC.

关键词： 6G Visible Light Communication multiple-input multiple-output Zonotopes Lower Bound Truncated Gaussian Distribution Uniform Distribution

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Rapid Implementation and Demonstration of Radio Applications Using WISCANet 32

Rapid Implementation and Demonstration of Radio Applications...

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32nd IEEE Annual International Symposium on Personal, Indoor and Mobile Radio Communications (IEEE PIMRC)

作者： Holtom, Jacob Gubash, Gerard Herschfelt, Andrew Ma, Owen Standage-Beier, Wylie Yu, Hanguang Bliss, Daniel W. Arizona State Univ Ctr Wireless Informat Syst & Computat Architectur Tempe AZ 85281 USA

ISBN: (纸本)9781728175867

Implementing new RF applications has traditionally required significant time and expertise, even for relatively simple algorithms. Software-defined radios (SDRs) have recently enabled rapid implementation and validation of RF applications without specialized hardware or advanced programming skills. We further facilitate this rapid application development by constructing WISCANet - a diverse network of commercial SDRs with specialized control software. WISCANet automatically configures these SDRs and controls transmit and receive events with minimal user input. This allows users to rapidly implement over-the-air RF applications by simply defining the baseband processing chain in software. Furthermore, WISCANet emulates real-time operations, which allows users to test real-time applications without the usual complications such as processing speed or hardware limitations. In this paper, we present recent improvements to the WISCA Software-Defined Radio Network (SDR-N). These improvements include configurable and flexible multi-channel phase coherence and support for both MATLAB and Python applications. The open source release of this software may be found on GitHub at: https://***/WISCA

关键词： Software-defined radio software-defined radio network cognitive radio multiple-input multiple-output

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Two-Stage Channel Estimation for Semi-Passive RIS-Assisted Millimeter Wave Systems

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SENSORS 2022年第15期22卷 5908-5908页

作者： Peng, Chengzuo Deng, Honggui Xiao, Haoqi Qian, Yuyan Zhang, Wenjuan Zhang, Yinhao Cent South Univ Sch Phys & Elect Lushan South Rd Changsha 410083 Peoples R China

In a reconfigurable intelligent surface (RIS) assisted millimeter Wave (mmWave) communication system, the channel coefficient increases exponentially with the number of RIS elements which results in expensive pilot overhead. Most previous works have proposed some channel estimation algorithms for the estimation accuracy of cascaded channels, which have improved the estimation accuracy, but the pilot overhead is discouraging in the estimation process. To improve the channel estimation accuracy with reduced pilot overhead, we propose a two-stage channel estimation protocol by exploiting semi-passive elements and the coherent time difference of the channel, where the quasi-static channel between the base stations (BS) and RIS is estimated at the RIS, and the user (UE)-RIS time-varying channel is estimated at the BS. In the first stage, we formulate the BS-RIS channel estimation as a mathematical optimization problem by an iterative weighting method and then propose a gradient descent (GD)-based algorithm to solve it. In the second stage, we first transform the received the UE-RIS signal model into an equivalent parallel factor (PARAFAC) tensor model and estimate the UE-RIS channel by the least-squares (LS) algorithm. The simulation results show that the proposed method has better estimation accuracy than the LS, compression sensing (CS) and minimum mean square error (MMSE) methods with less pilot overhead, and the spectral efficiency is improved by at least 10.5% compared to the other three methods.

关键词： reconfigurable intelligent surface semi-passive channel estimation multiple-input multiple-output

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

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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

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Physical Layer Security Optimization for MIMO Enabled Visible Light Communication Networks

Physical Layer Security Optimization for MIMO Enabled Visibl...

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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

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Recent Trends in Coherent Free-Space Optical Communications 4

Recent Trends in Coherent Free-Space Optical Communications

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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

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

COMPACT RECONFIGURABLE POLARIZATION PLASMA SQUARE MICROSTRIP...

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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

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

IEEE PHOTONICS JOURNAL

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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

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

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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

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