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Beamforming and fronthaul compression design for intelligent reflecting surface aided cloud radio access networks Research Article

Yu ZHANG, Xuelu WU, Hong PENG, Caijun ZHONG, Xiaoming CHEN,yzhang@zjut.edu.cn,ph@zjut.edu.cn,caijunzhong@zju.edu.cn,chen_xiaoming@zju.edu.cn

Frontiers of Information Technology & Electronic Engineering 2022, Volume 23, Issue 1,   Pages 31-46 doi: 10.1631/FITEE.2100307

Abstract: Owing to the inherent central information processing and resource management ability, the is a promising network structure for an intelligent and simplified sixth-generation (6G) wireless network. Nevertheless, to further enhance the capacity and coverage, more radio remote heads (RRHs) as well as high-fidelity and low-latency fronthaul links are required, which may lead to high implementation cost. To address this issue, we propose to exploit the as an alternative way to enhance the C-RAN, which is a low-cost and energy-efficient option. Specifically, we consider the uplink transmission where multi-antenna users communicate with the baseband unit (BBU) pool through multi-antenna RRHs and multiple IRSs are deployed between the users and RRHs. RRHs can conduct either point-to-point (P2P) compression or Wyner-Ziv coding to compress the received signals, which are then forwarded to the BBU pool through fronthaul links. We investigate the joint design and optimization of user transmit beamformers, IRS passive beamformers, and noise covariance matrices to maximize the uplink sum rate subject to fronthaul capacity constraints under P2P compression and Wyner-Ziv coding. By exploiting the Arimoto-Blahut algorithm and semi-definite relaxation (SDR), we propose a successive convex approximation approach to solve non-convex problems, and two iterative algorithms corresponding to P2P compression and Wyner-Ziv coding are provided. Numerical results verify the performance gain brought about by deploying IRS in C-RAN and the superiority of the proposed joint design.

Keywords： Cloud radio access network (C-RAN)     Intelligent reflecting surface (IRS)     Transmit beamforming     Fronthaul compression    

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Beamforming techniques for massive MIMO systems in 5G: overview, classification, and trends for future research Review

Ehab ALI, Mahamod ISMAIL, Rosdiadee NORDIN, Nor Fadzilah ABDULAH

Frontiers of Information Technology & Electronic Engineering 2017, Volume 18, Issue 6,   Pages 753-772 doi: 10.1631/FITEE.1601817

Abstract: Massive multiple-input multiple-output (MIMO) systems combined with beamforming antenna array technologies are expected to play a key role in next-generation wireless communication systems (5G), which will be deployed in 2020 and beyond. The main objective of this review paper is to discuss the state-of-the-art research on the most favourable types of beamforming techniques that can be deployed in massive MIMO systems and to clarify the importance of beamforming techniques in massive MIMO systems for eliminating and resolving the many technical hitches that massive MIMO system implementation faces. Classifications of optimal beamforming techniques that are used in wireless communication systems are reviewed in detail to determine which techniques are more suitable for deployment in massive MIMO systems to improve system throughput and reduce intra- and inter-cell interference. To overcome the limitations in the literature, we have suggested an optimal beamforming technique that can provide the highest performance in massive MIMO systems, satisfying the requirements of next-generation wireless communication systems.

Keywords： Beamforming classifications     Massive MIMO     Hybrid beamforming     Millimetre-wave beamforming    

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On Differentiation Among Pilot Signals of Multiple Mobile Targets in Retro-Reflective Beamforming for Wireless Power Transmission Article

Xin Wang, Long Li, Tie Jun Cui, Mingyu Lu

Engineering 2023, Volume 30, Issue 11,   Pages 55-62 doi: 10.1016/j.eng.2023.08.010

Abstract:

An experimental study is conducted on several retro-reflective beamforming schemes for wireless power transmission to multiple wireless power receivers (referred to herein as "targets"). The experimental results demonstrate that, when multiple targets broadcast continuous-wave pilot signals at respective frequencies, a retro-reflective wireless power transmitter is capable of generating multiple wireless power beams aiming at the respective targets as long as the multiple pilot signals are explicitly separated from one another by the wireless power transmitter. However, various practical complications are identified when the pilot signals of multiple targets are not appropriately differentiated from each other by the wireless power transmitter. Specifically, when multiple pilot signals are considered to be carried by the same frequency, the wireless power transmission performance becomes heavily dependent on the interaction among the pilot signals, which is highly undesirable in practice. In conclusion, it is essential for a retro-reflective wireless power transmitter to explicitly discriminate multiple targets' pilot signals among each other.

Keywords： Wireless power transmission     Microwave antenna array     Retro-reflective beamforming     Pilot signal     Multiple access    

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Correlated channelmodel-based securecommunications in dual-hopwireless communication networks Article

Zhen-hua YUAN, Chen CHEN, Xiang CHENG, Guo-cheng LV, Liu-qing YANG, Ye JIN

Frontiers of Information Technology & Electronic Engineering 2017, Volume 18, Issue 6,   Pages 796-807 doi: 10.1631/FITEE.1700023

Abstract: This article is focused on secure relay beamformer design with a correlated channel model in the relay-eavesdropper network. In this network, a single-antenna source-destination pair transmits secure information with the help of an amplify-and-forward (AF) relay equipped with multiple antennas, and the legitimate and eavesdropping channels are correlated. The relay cannot obtain the instantaneous channel state information (CSI) of the eavesdropper, and has only the knowledge of correlation information between the legitimate and eavesdropping channels. Depending on this information, we derive the conditional distribution of the eavesdropping channel. Two beamformers at the relay are studied for the approximate ergodic secrecy rate: (1) the generalized match-andforward (GMF) beamformer to maximize the legitimate channel rate, and (2) the general-rank beamformer (GRBF). In addition, one lower-bound-maximizing (LBM) beamformer at the relay is discussed for maximizing the lower bound of the ergodic secrecy rate. We find that the GMF beamformer is the optimal rank-one beamformer, that the GRBF is the iteratively optimal beamformer, and that the performance of the LBM beamformer for the ergodic secrecy rate gets close to that of the GRBF for the approximate secrecy rate. It can also be observed that when the relay has lower power or the channel gain of the second hop is low, the performance of the GMF beamformer surpasses that of the GRBF. Numerical results are presented to illustrate the beamformers’ performance.

Keywords： Physical layer security     Relay beamforming     Correlated channels     Ergodic secrecy rate    

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Joint cooperative beamforming and artificial noise design for secureAF relay networks with energy-harvesting eavesdroppers Article

He-hao NIU, Bang-ning ZHANG, Dao-xing GUO, Yu-zhen HUANG, Ming-yue LU

Frontiers of Information Technology & Electronic Engineering 2017, Volume 18, Issue 6,   Pages 850-862 doi: 10.1631/FITEE.1601832

Abstract: In this paper, we investigate physical layer security for simultaneous wireless information and power transfer in amplify-and-forward relay networks. We propose a joint robust cooperative beamforming and artificial noise scheme for secure communication and efficient wireless energy transfer. Specifically, by treating the energy receiver as a potential eavesdropper and assuming that only imperfect channel state information can be obtained, we formulate an optimization problem to maximize the worst-case secrecy rate between the source and the legitimate information receiver under both the power constraint at the relays and the wireless power harvest constraint at the energy receiver. Since such a problem is non-convex and hard to tackle, we propose a two-level optimization approach which involves a one-dimensional search and semidefinite relaxation. Simulation results show that the proposed robust scheme achieves better worst-case secrecy rate performance than other schemes.

Keywords： Simultaneous wireless information and power transfer     Physical layer security     Relay networks     Cooperative beamforming     Artificial noise    

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Millimeter-wave wireless communications for home network in fiber-to-the-room scenario

Chao He, Zhixiong Ren, Xiang Wang, Yan Zeng, Jian Fang, Debin Hou, Le Kuai, Rong Lu, Shilin Yang, Zhe Chen, Jixin Chen,charles.he@huawei.com,renzhixiong@huawei.com,eric.wangxiang@huawei.com,tony.zengyan@huawei.com,fangjian@srrc.org.cn,dbhou@seu.edu.cn,230159362@seu.edu.cn,ronglu@seu.edu.cn,yang_shilinnudt@163.com,zhechen@seu.edu.cn,jxchen@seu.edu.cn

Frontiers of Information Technology & Electronic Engineering 2021, Volume 22, Issue 4,   Pages 441-456 doi: 10.1631/FITEE.2000440

Abstract: Millimeter-wave (mmWave) technology has been well studied for both outdoor long-distance transmission and indoor short-range communication. In the recently emerging (FTTR) architecture in the of the fifth generation fixed networks (F5G), mmWave technology can be cascaded well to a new optical network terminal in the room to enable extremely high data rate communication (i.e., >10 Gb/s). In the FTTR+mmWave scenario, the rapid degradation of the mmWave signal in long-distance transmission and the significant loss against wall penetration are no longer the bottlenecks for real application. Moreover, the surrounding walls of every room provide excellent isolation to avoid interference and guarantee security. This paper provides insights and analysis for the new FTTR+mmWave architecture to improve the customer experience in future broadband services such as immersive audiovisual videos.

Keywords： 光纤到屋；毫米波；Q波段；云虚拟现实；家庭网络；波束成形；射频集成电路    

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Fundamentals and Processes of Fluid Pressure Forming Technology for Complex Thin-Walled Components Review

Shijian Yuan

Engineering 2021, Volume 7, Issue 3,   Pages 358-366 doi: 10.1016/j.eng.2020.08.014

Abstract:

A new generation of fluid pressure forming technology has been developed for the three typical structures of tubes, sheets, and shells, and hard-to-deform material components that are urgently needed for aerospace, aircraft, automobile, and high-speed train industries. In this paper, an overall review is introduced on the state of the art in fundamentals and processes for lower-pressure hydroforming of tubular components, double-sided pressure hydroforming of sheet components, die-less hydroforming of ellipsoidal shells, and dual hardening hot medium forming of hard-to-deform materials. Particular attention is paid to deformation behavior, stress state adjustment, defect prevention, and typical applications. In addition, future development directions of fluid pressure forming technology are discussed, including hyper lower-loading forming for ultra-large non-uniform components, precision forming for intermetallic compound and high-entropy alloy components, intelligent process and equipment, and precise finite element simulation of inhomogeneous and strong anisotropic thin shells.

Keywords： Fluid pressure forming     Hydroforming     Hot medium pressure forming     Thin-walled components     Stress state    

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Progress of Materials Processing and Solidification Technologies

Jie Wanqi

Strategic Study of CAE 2002, Volume 4, Issue 6,   Pages 1-4

Abstract:

By analyzing the progress of materials processing, the application and the importance of solidification technologies in the field are stressed. It is pointed out that the solidification technologies offer some new method´s for the preparation of advanced materials as well as powerful ways for improving the traditional materials processing, which is now on the way of optimizing the facts of shape forming, microstructure improving, consume reducing and environment protection. Some emerging research topics about solidification processing and the possible technological progresses are also predicated.

Keywords： materials     processing     solidification technology    

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A New Technology of Plastic Forming Plate by Laser Peening

Zhou Jianzhong,Zhang Xingquan,Wang Guanglong,Yang Chaojun,Zhang Yongkang

Strategic Study of CAE 2005, Volume 7, Issue 11,   Pages 94-97

Abstract:

Laser peening forming is an emerging modern process developed from laser shock strengthening. During a laser peening event, pressures well above the dynamic yield strength of the material are imparted to the target in a fraction of nanoseconds. The severity of the loading causes local plastic deformation which ultimately results in the development of the uneven residual stress along the thickness of plate, which pushes the plate to deform. Different parameters of laser can induce different residual stress which make plate achieve different shapes, so controlling technical parameters of laser peening can control the distribution of residual stress, indirectly controlling the deformation of plate to satisfy its design. Laser peening forming is a flexible technology, which can form tight radii in thick material with high accuracy and compressive stress into its surface to extend fatigue lifetime. In the end of the paper, the application prospect of technology is outlined.

Keywords： laser peening forming     plate     residual stress    

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Study on the experiment of hot stamping for front bumper

Guo Yihui,Ma Mingtu,Zhang Yisheng,Song Leifeng and Fang Gang

Strategic Study of CAE 2014, Volume 16, Issue 1,   Pages 76-80

Abstract:

Based on the front bumper of a commercial vehicle，the hot stamping mould was developed，and the hot stamping experiment was carried out. The laser scanning，microstructure， microhardness and mechanical properties of the components were detected. The results showed that the shape of the components meets the design requirements；the structure of components after hot stamping is martensite structure；the hardness of the components is more than HV400； the yield strength of the components is more than 1 000 MPa；the tensile strength of the components is more than 1 400 MPa；the elongation exceeds 10 %.

Keywords： front bumper     hot stamping     mechanical properties    

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Development and formability analysis of TRIP seamless steel tube

Zhang Zicheng and Zhu Fuxian

Strategic Study of CAE 2014, Volume 16, Issue 2,   Pages 46-52

Abstract:

In the present study，the production technology of transformation induced plasticity（TRIP）steel was firstly introduced in the steel tube manufacture field. The TRIP steel tubes with a microstructure of ferrite，bainite，retained austenite and a little martensite were successfully fabricated with both of the two-stage heat treatment technique and continuous heat treatment technique using a cold drawn steel tube. The ring tensile test and cold bending process were carried out to study the formability of the newly developed TRIP seamless steel tube. The results showed that the TRIP seamless steel tubes have a good cold formability，and they are available to be used in the tube hydroforming process. In addition，the equipment of continuous heat treatment developed in the current study can be used to produce TRIP steel tube and it may serve as an important reference for the industrial production of TRIP steel tube.

Keywords： TRIP steel     heat treatment     formability     steel tube     microstructure    

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The lean forming technology for auto sheet metal

Lin Zhongqin,Li Shuhui,Wang Wurong,Lai Xinmin

Strategic Study of CAE 2009, Volume 11, Issue 11,   Pages 22-29

Abstract:

The lean forming technology for auto sheet metal has been proposed, which consists of a proper material selection method considering the forming characteristic, a hybrid optimization methodology for effective drawbead force design and an experiment platform with the control of variable blank holder force. Aiming at decreasing the forming sensitivity to variation in materials and process, a forming robust design methodology has been studied. The technical framework for auto sheet metal lean forming was constructed based on the idea of proper material selection, process optimization and robust control. Through more than 10 years of application in Baosteel and some automobile plants, 50 % market sharing has been targeted for Baosteel auto steel sheet, which effectively promotes the development of application technologies for home-made auto sheet metal.

Keywords： auto sheet metal     lean forming     proper material selection     process optimization     robust control    

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Three kinds of strength level of DP steel formability

Fang Gang,Ma Mingtu,Dongun Kim,Jin Qingsheng,Song Leifeng and Jiang Songwei

Strategic Study of CAE 2014, Volume 16, Issue 1,   Pages 66-70

Abstract:

For three different strength level， different thicknesses were systematically formability test，Comprehensive analysis of the mechanical properties of （dual- phase）DP steel，cupping performance，cold bending，forming limit. Studies show that：Elongation and the value of n for DP steel decreases with rising intensity level. Cupping test results show that the height of the cupping with the DP steels up strength level decreases，and increases with increasing thickness of the material. Duplex steel cold bending properties with increased material strength level decreases. Bulging under biaxial strain tests showed that DP steel has good formability. Based on mild steel FLD0 empirical formula can’t be directly applied to the DP steel.

Keywords： DP steel     formability     forming limits    

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Dot-shaped beamforming analysis of subarray-based sin-FDA Research Article

Bo Wang, Jun-wei Xie, Jing Zhang, Jia-ang Ge,wb_wangbo1991@163.com

Frontiers of Information Technology & Electronic Engineering 2019, Volume 20, Issue 10,   Pages 1429-1444 doi: 10.1631/FITEE.1800722

Abstract: Phased array (PA) radar is one of the most popular types of radar. In contrast to PA, the (FDA) is a potential solution to suppress range-related interference because of its time-range-angle-dependent beampattern. However, the range-angle coupling inherent in the FDA transmit beampattern may degrade the output signal-to-interference-plus-noise ratio (SINR). We propose a method based on the analyzed four subarray-based FDAs and subarray-based planar FDAs using a sinusoidally increasing frequency offset with elements transmitting at multiple frequencies. The numerical results show that the proposed approach outperforms the existing log-FDA with logarithmical frequency offset in transmit energy focus, sidelobe suppression, and array resolution. Comparative simulation results validate the effectiveness of the proposed method.

Keywords： 频率分集阵列；子阵频率分集阵列；解耦；点状波束形成    

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Study on TA2 Sheet Metal Bending With Thermal Stress Induced by Laser and Its Mechanical Properties

Zhou Yijun,Zhang Yongkang,You Wenming,Yin Chen,Zhang Chengyang

Strategic Study of CAE 2007, Volume 9, Issue 10,   Pages 40-44

Abstract:

A 2. 5 kW CO2 laser,  a HVS-1000 Micro-hardness measuring instrument and an X-350A X-ray stress measuring instrument were adopted in the experiment where 0. 6mm-thickn sheet steel of TA2 was studied to evaluate the process parameters of bending with thermal stress induced by laser.  Bending angle was measured as the function of main processing parameters.  These processing parameters were arranged according to the theory of orthotropic experiment.  Distribution of residual stress on the surface and variation of micro-hardness on the cross section of samples were studied after forming.  The results show that these parameters bring different effects.  The number of passes ranks first,  followed by laser spot in terms of their effect on the bending angle,  with power of laser beam and scan speed being the last two factors.  Parameters of laser forming also have some influence on the distribution of residual stress on the surface of samples.  Certain regularity appears in the variation of micro-hardness on the cross section of samples.

Keywords： laser technology     thermal stress     sheet metal bending     residual stress     micro-hardness    

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Title Author Date Type Operation

Beamforming and fronthaul compression design for intelligent reflecting surface aided cloud radio access networks

Yu ZHANG, Xuelu WU, Hong PENG, Caijun ZHONG, Xiaoming CHEN,yzhang@zjut.edu.cn,ph@zjut.edu.cn,caijunzhong@zju.edu.cn,chen_xiaoming@zju.edu.cn

Journal Article

Beamforming techniques for massive MIMO systems in 5G: overview, classification, and trends for future research

Ehab ALI, Mahamod ISMAIL, Rosdiadee NORDIN, Nor Fadzilah ABDULAH

Journal Article

On Differentiation Among Pilot Signals of Multiple Mobile Targets in Retro-Reflective Beamforming for Wireless Power Transmission

Xin Wang, Long Li, Tie Jun Cui, Mingyu Lu

Journal Article

Correlated channelmodel-based securecommunications in dual-hopwireless communication networks

Zhen-hua YUAN, Chen CHEN, Xiang CHENG, Guo-cheng LV, Liu-qing YANG, Ye JIN

Journal Article

Joint cooperative beamforming and artificial noise design for secureAF relay networks with energy-harvesting eavesdroppers

He-hao NIU, Bang-ning ZHANG, Dao-xing GUO, Yu-zhen HUANG, Ming-yue LU

Journal Article

Millimeter-wave wireless communications for home network in fiber-to-the-room scenario

Chao He, Zhixiong Ren, Xiang Wang, Yan Zeng, Jian Fang, Debin Hou, Le Kuai, Rong Lu, Shilin Yang, Zhe Chen, Jixin Chen,charles.he@huawei.com,renzhixiong@huawei.com,eric.wangxiang@huawei.com,tony.zengyan@huawei.com,fangjian@srrc.org.cn,dbhou@seu.edu.cn,230159362@seu.edu.cn,ronglu@seu.edu.cn,yang_shilinnudt@163.com,zhechen@seu.edu.cn,jxchen@seu.edu.cn

Journal Article

Fundamentals and Processes of Fluid Pressure Forming Technology for Complex Thin-Walled Components

Shijian Yuan

Journal Article

Progress of Materials Processing and Solidification Technologies

Jie Wanqi

Journal Article

A New Technology of Plastic Forming Plate by Laser Peening

Zhou Jianzhong,Zhang Xingquan,Wang Guanglong,Yang Chaojun,Zhang Yongkang

Journal Article

Study on the experiment of hot stamping for front bumper

Guo Yihui,Ma Mingtu,Zhang Yisheng,Song Leifeng and Fang Gang

Journal Article

Development and formability analysis of TRIP seamless steel tube

Zhang Zicheng and Zhu Fuxian

Journal Article

The lean forming technology for auto sheet metal

Lin Zhongqin,Li Shuhui,Wang Wurong,Lai Xinmin

Journal Article

Three kinds of strength level of DP steel formability

Fang Gang,Ma Mingtu,Dongun Kim,Jin Qingsheng,Song Leifeng and Jiang Songwei

Journal Article

Dot-shaped beamforming analysis of subarray-based sin-FDA

Bo Wang, Jun-wei Xie, Jing Zhang, Jia-ang Ge,wb_wangbo1991@163.com

Journal Article

Study on TA2 Sheet Metal Bending With Thermal Stress Induced by Laser and Its Mechanical Properties

Zhou Yijun,Zhang Yongkang,You Wenming,Yin Chen,Zhang Chengyang

Journal Article