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Absorption-Dominant mmwave EMI Shielding Films with Ultralow Reflection using Ferromagnetic Resonance Frequency Tunable M-Type Ferrites

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Nano-Micro Letters 2023年第6期15卷 1-23页

作者： Horim Lee Seung Han Ryu Suk Jin Kwon Jae Ryung Choi Sang‑bok Lee Byeongjin Park Composites Research Division Korea Institute of Materials Science797 ChangwondaeroSeongsan‑GuChangwonGyeongsangnam‑Do 51508Republic of Korea

Although there is a high demand for absorption-dominant electromagnetic interference(EMI) shielding materials for 5G millimeter-wave(mmwave) frequencies, most current shielding materials are based on reflection-dominant conductive materials. While there are few absorption-dominant shielding materials proposed with magnetic materials, their working frequencies are usually limited to under 30 GHz. In this study, a novel multi-band absorption-dominant EMI shielding film with M-type strontium ferrites and a conductive grid is proposed. This film shows ultralow EMI reflection of less than 5% in multiple mmwave frequency bands with sub-millimeter thicknesses, while shielding more than 99.9% of EMI. The ultralow reflection frequency bands are controllable by tuning the ferromagnetic resonance frequency of M-type strontium ferrites and composite layer geometries. Two examples of shielding films with ultralow reflection frequencies, one for 39 and 52 GHz 5G telecommunication bands and the other for 60 and 77 GHz autonomous radar bands, are presented. The remarkably low reflectance and thinness of the proposed films provide an important advancement toward the commercialization of EMI shielding materials for 5G mmwave applications.

关键词： 5G communication mmwave EMI shielding M-type ferrites

Beam Training and Tracking in mmwave Communication:A Survey

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China Communications 2024年第6期21卷 1-22页

作者： Wang Yi Wei Zhiqing Feng Zhiyong Yangtze Delta Region Institute(Quzhou) University of Electronic Science and Technology of ChinaQuzhou 324003China School of Information and Communication Engineering University of Electronic Science and Technology of ChinaChengdu 611731China Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and TelecommunicationsBeijing 100876China

Communicating on millimeter wave(mmwave)bands is ushering in a new epoch of mobile communication which provides the availability of 10 Gbps high data rate ***,mmwave links are easily prone to short transmission range communication because of the serious free space path loss and the blockage by *** overcome these challenges,highly directional beams are exploited to achieve robust links by hybrid *** aligning the transmitter and receiver beams,*** training,is vitally important to high data rate ***,it may cause huge overhead which has negative effects on initial access,handover,and ***,the mobility patterns of users are complicated and dynamic,which may cause tracking error and large tracking *** efficient beam tracking method has a positive effect on sustaining robust *** article provides an overview of the beam training and tracking technologies on mmwave bands and reveals the insights for future research in the 6th Generation(6G)mobile ***,some open research problems are proposed to realize fast,accurate,and robust beam training and *** hope that this survey provides guidelines for the researchers in the area of mmwave communications.

关键词： 6G beam tracking beam training beamforming mmwave

Improved Hybrid Beamforming for mmwave Multi-User Massive MIMO

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Computers, Materials & Continua 2021年第6期67卷 3057-3070页

作者： Ji-Sung Jung Won-Seok Lee Yeong-Rong Lee Jaeho Kim Hyoung-Kyu Song Department of Information and Communication Engineering and Convergence Engineering for Intelligent Drone Sejong UniversitySeoul05006Korea Department of Electrical Engineering Sejong UniversitySeoul05006Korea

Massive multiple input multiple output(MIMO)has become essential for the increase of capacity as the millimeter-wave(mmwave)communication is ***,hybrid beamforming systems have been studied since full-digital beamforming is impractical due to high cost and power consumption of the radio frequency(RF)*** paper proposes a hybrid beamforming scheme to improve the spectral efciency for multi-user MIMO(MU-MIMO)*** a frequency selective fading environment,hybrid beamforming schemes suffer from performance degradation since the analog precoder performs the same precoding for all *** mitigate performance degradation,this paper uses the average channel covariance matrix for all subcarriers and considers an iterative algorithm to design analog precoder using approximation *** analog precoder is iteratively updated for each column until it *** proposed scheme can reduce errors in the approximating process of the overall spectral *** scheme can be applied to fully-connected and partially-connected *** simulation results show that spectral efciency performance for the proposed scheme is better than the conventional *** proposed scheme can achieve similar performance with full-digital beamforming by using a sufciently large number of RF ***,this paper shows that the proposed scheme outperforms other schemes in the frequency selective fading *** performance improvement can be achieved in both structures.

关键词： Hybrid precoding massive MIMO MU-MIMO mmwave frequency selective fading

A Highly Efficient Algorithm for Phased-Array mmwave Massive MIMO Beamforming

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Computers, Materials & Continua 2021年第10期69卷 679-694页

作者： Ayman Abdulhadi Althuwayb Fazirulhisyam Hashim Jiun Terng Liew Imran Khan Jeong Woo Lee Emmanuel Ampoma Affum Abdeldjalil Ouahabi Sébastien Jacques Department of Electrical Engineering Jouf UniversitySakakaAljouf72388Kingdom of Saudi Arabia Department of Computer and Communication Systems Engineering Faculty of EngineeringUniversiti Putra Malaysia(UPM)Serdang43400Malaysia Department of Electrical Engineering University of Engineering and Technology PeshawarPakistan School of Electrical and Electronics Engineering Chung-Ang UniversitySeoul06974Korea Electrical and Electronic Department Kwame Nkrumah University of Science and TechnologyKumasiGhana UMR 1253 iBrainUniversitéde ToursINSERMToursFrance LIMPAF Laboratory Department of Computer ScienceUniversity of BouiraBouira10000Algeria University of Tours(France) GREMAN UMR 7347CNRSINSA Centre Val-de-LoireTours37100France

With the rapid development of the mobile internet and the internet of things(IoT),the fifth generation(5G)mobile communication system is seeing explosive growth in data *** addition,low-frequency spectrum resources are becoming increasingly scarce and there is now an urgent need to switch to higher frequency *** wave(mmwave)technology has several outstanding features—it is one of the most well-known 5G technologies and has the capacity to fulfil many of the requirements of future wireless ***,it has an abundant resource spectrum,which can significantly increase the communication rate of a mobile communication *** such,it is now considered a key technology for future mobile *** communication technology also has a more open network architecture;it can deliver varied services and be applied in many *** contrast,traditional,all-digital precoding systems have the drawbacks of high computational complexity and higher power *** paper examines the implementation of a new hybrid precoding system that significantly reduces both calculational complexity and energy *** primary idea is to generate several sub-channels with equal gain by dividing the channel by the geometric mean decomposition(GMD).In this process,the objective function of the spectral efficiency is derived,then the basic tracking principle and least square(LS)techniques are deployed to design the proposed hybrid *** results show that the proposed algorithm significantly improves system performance and reduces computational complexity by more than 45%compared to traditional algorithms.

关键词： 5G mmwave phased array algorithm antenna beamforming

Propagation Characterization and Analysis for 5G mmwave Through Field Experiments

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Computers, Materials & Continua 2021年第8期68卷 2249-2264页

作者： Faizan Qamar Mhd Nour Hindia Tharek Abd Rahman Rosilah Hassan Kaharudin Dimyati Quang Ngoc Nguyen Centre for Cyber Security Faculty of Information Science and TechnologyUniversiti Kebangsaan Malaysia(UKM)43600BangiSelangorMalaysia Department of Electrical Engineering Faculty of EngineeringUniversity of Malaya50603Kuala LumpurMalaysia Wireless Communication Centre Faculty of Electrical EngineeringUniversiti Teknologi Malaysia81310SkudaiJohorMalaysia Department of Computer Science and Communications Engineering Faculty of Science and EngineeringWaseda UniversityTokyo169-8050Japan

The 5G network has been intensively investigated to realize the ongoing early deployment stage as an effort to match the exponential growth of the number of connected users and their increasing demands for high throughput,bandwidth with Quality of Service(QoS),and low *** that most of the spectrums below 6 GHz are nearly used up,it is not feasible to employ the traditional spectrum,which is currently in ***,a promising and highly feasible effort to satisfy this insufficient frequency spectrum is to acquire new frequency bands for next-generation mobile *** this end,the primary effort has been focused on utilizing the millimeter-wave(mmwave)as the most promising candidate for the frequency ***,though the mmwave frequency band can fulfill the desired bandwidth requirements,it has been demonstrated to endure several issues like scattering,atmospheric absorption,fading,and especially penetration losses compared to the existing sub-6 GHz frequency ***,it is fundamental to optimize the mmwave band propagation channel to facilitate the practical 5G implementation for the network ***,this study intends to investigate the outdoor channel characteristics of 26,28,36,and 38 GHz frequency bands for the communication infrastructure at the building to the ground floor in both Line of Sight(LOS)and Non-Line of Sight(NLOS)*** experimental campaign has studied the propagation path loss models such as Floating-Intercept(FI)and Close-In(CI)for the building to ground floor environment in LOS and NLOS *** findings obtained from the field experiments clearly show that the CI propagation model delivers much better performance in comparison with the FI model,thanks to its simple setup,accuracy,and precise function.

关键词： 5G mmwave propagation channel path loss channel characterization field experiment

Hybrid and Full-Digital Beamforming in mmwave Massive MIMO Systems: A Comparison Considering Low-Resolution ADCs

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China Communications 2019年第6期16卷 91-102页

作者： Wence Zhang Xiaoxuan Xia Yinkai Fu Xu Bao School of Computer Science and Communications Engineering Jiangsu UniversityZhenjiang 212013China National Mobile Communications Research Lab. Southeast UniversityNanjing 210089China

In a millimeter-wave(mmwave)Massive multiple-input multiple-output(MIMO)systems,full-digital beamforming(i.e.,connecting each antenna with a specific radio-frequency(RF)chain)becomes inefficient due to the hardware cost and power ***,hybrid analog and digital transceiver where the number of RF chains are much smaller than that of the antennas has drawn great research *** this work,we investigate the use of low-resolution analog-to-digital converters(ADCs)in the uplink of multi-user hybrid and full-digital mmwave Massive MIMO *** be specific,we compare the performance of full-digital minimum mean square error(MMSE)and hybrid MMSE beamforming in both sum rates and energy *** approximations of sum rates and energy efficiency are provided for both schemes,which captures the dominant *** analytical results show that full-digital beamforming outperforms hybrid beamforming in terms of sum rates and requires only a small portion(γ)of antennas used by hybrid beamforming to achieve the same sum *** given sufficient condition for full-digital beamforming to outperform hybrid beamforming in terms of energy ***,an algorithm is proposed to search for the optimal ADC resolution *** results demonstrate the correctness of the analysis.

关键词： hybrid massive MIMO mmwave MMSE low-resolution ADCs

Long-Range VNA-Based Channel Sounder: Design and Measurement Validation at mmwave and Sub-THz Frequency Bands

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China Communications 2022年第11期19卷 47-59页

作者： Mikkel Bengtson Yejian Lyu Wei Fan Department of Electronic Systems Aalborg UniversityAalborgØst 9220Denmark

With the increasing demand for high bandwidth wireless communication systems,and with a congested spectrum in the sub-6 GHz frequency bands,researchers have been looking into exploration of millimeter wave(mmwave)and sub-terahertz(subTHz)frequency *** modeling is essential for system design and performance evaluation of new wireless communication *** channel modeling relies on reliable measured channel data,which is collected by high-fidelity channel ***,it is of importance to understand to which extent channel parameters are frequency dependent in typical deployment scenario(including both indoor short-range and outdoor long-range scenarios).To achieve this purpose,this paper presents a stateof-art long-range 28 GHz and 300 GHz VNA-based channel sounder using optical cable solutions,which can support a measurement range up to 300 m and 600 m in principle,*** design,development and validation of the long-range channel sounders at mmwave and sub-THz bands are reported,with a focus on their system principle,link budget,and backto-back ***,a measurement campaign in an indoor corridor is performed using the developed 300 GHz system and 28 GHz channel sounding *** measured channels at the 28 GHz and 300 GHz channels are shown to be highly sparse and specular.A higher number of Multi Path Components(MPC)are observed for the 28 GHz system,while the same main MPC are observed for both systems.

关键词： mmwave channel sounding sub-THz radio propagation beyond 5G communications

Sparse array of sub-surface aided blockage-free multi-user mmwave communication systems

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Digital Communications and Networks 2020年第3期6卷 292-303页

作者： Weicong Chen Xi Yang Shi Jin Pingping Xu National Mobile Communications Research Laboratory Southeast UniversityNanjing210096P.R.China

Recently,Reconfigurable Intelligent Surfaces(RISs)have drawn intensive attention in the realization of the smart radio ***,existing works mainly consider the RIS as a whole uniform plane,which may be unrealistic to be installed on the facade of buildings when the RIS is extremely *** contrast,this paper investigates a practical Sparse Array of Sub-surface(SAoS)deployment of the RIS for uplink multi-user millimeter Wave(mmwave)communication systems,in which the Mobile Stations(MSs)are distributed in the blind coverage area due to the *** order to exploit the benefits of the sparse deployment,the correlation of the effective channel is firstly *** the approximation and lower bounds of the ergodic spectral efficiency are derived under frequency and spatial multiplexing scenarios,*** on the autocorrelation of the effective channel,we obtain an optimal reflect coefficient design as well as the deployment guidelines of RIS ***,the RIS tile scheduling algorithms are also *** results show that the ergodic spectral efficiency approximation matches well with the Monte Carlo result under frequency multiplexing scenarios,and the lower bound is tight under spatial multiplexing scenarios only when the effective channel is strongly *** the basis of the RIS tile scheduling algorithm and the reflect coefficient design,the system performance can be significantly improved under frequency multiplexing *** the other hand,by deploying more sparse RIS tiles,we can increase the multiplexing gain under spatial multiplexing scenarios.

关键词： Sparse array Reconfigurable intelligent surface Multi-user Blockage-free mmwave

Hybrid Beamforming Design for Uplink mmwave Systems with a Predefined Low-Resolution Codebook

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Journal of Communications and Information Networks 2019年第3期4卷 1-8页

作者： Chao Han Jiaxing Wang Jingchao Wang Lin Bai School of Electronic and Information Engineering Beihang UniversityBeijing 100191China Peng Cheng Laboratory Shenzhen 518055China School of Cyber Science and Technology Beihang UniversityBeijing 100191China Beijing Laboratory for General Aviation Technology Beihang UniversityBeijing 100191China

In millimeter wave(mmwave)systems,desirable spectral efficiency can be realized by the hybrid beamformer in which a large sized analog beamformer and a small sized baseband digital beamformer are cascade-connected together to reduce the system ***,most of works focus on the beamforming(or combining)method design with an impractical analog beamformer where the infinite-resolution phase shifts(PSs)are *** this paper,a more practical hybrid beamformer with low-resolution PSs is considered and the hybrid receiver beamforming method under the multiuser uplink communication circumstance is *** the system performance is mainly constrained by the interuser interference,we propose a novel two-stage hybrid receiver beamforming against the inter-user interference with comparable computational complexity than that of the recently presented ***,to enhance the performance of systems with many users,we propose a novel multiuser selection algorithm by exploiting the multiuser diversity ***,from the simulation results,we can verify the superiority of the proposed method over the comparing method in error probability and spectrum efficiency.

关键词： mmwave hybrid beamformer detection multiuser selection error probability