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Self-attention reinforcement learning for multi-beam combining in mmW ave 3D-MIMO systems

Science China(information Sciences) 2023年第6期66卷 204-221页

作者： Yingzhi HUANG Zhaoyang ZHANG Jingze CHE Zhaohui YANG Qianqian YANG Kai-Kit WONG College of information Science and electronic engineering Zhejiang University department of electronic and Electrical engineering University College London

Machine learning(ML)has been empowering all aspects of the wireless communication system design, among which, the reinforcement learning(RL)-based approaches have attracted a lot of research attention since they can interact with the environment directly and learn from the collected experiences efficiently. In this paper, we propose a novel and efficient RL-based multi-beam combining scheme for future millimeter-wave(mmWave)three-dimensional(3D)multi-input multi-output(MIMO)communication systems. The proposed scheme does not require perfect channel state information(CSI)or precise user location information which both are generally difficult to obtain in practice, and well addresses the crucial challenge of computational complexity incurred by the extremely huge state and action spaces associated with multiple users, multiple paths, and multiple 3D beams. In particular, a self-attention deep deterministic policy gradient(DDPG)-based beam selection and combination framework is proposed to learn the 3D beamforming pattern without CSI adaptively. We aim to maximize the sum-rate of the mmWave 3D-MIMO system by optimizing the serving beam set and the corresponding combining weights for each user. To this end, the transformer is incorporated into the DDPG to obtain the global information of the input elements and capture the signal directions precisely, which leads to a near-optimal beamformer design. Simulation results verify the superiority of the proposed self-attention DDPG over conventional ML-based beamforming schemes in terms of sum-rate under various scenarios.

关键词： reinforcement learning (RL) deep deterministic policy gradient (DDPG) self-attention pre-coding/combining millimeter-wave (mmWave) multi-input multi-output (MIMO)

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Joint information transmission design for intelligent reflecting surface aided system with discrete phase shifts

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Science China(information Sciences) 2023年第3期66卷 253-262页

作者： Qin TAO Shuowen ZHANG Caijun ZHONG Yushu ZHANG College of information Science and electronic engineering Zhejiang University Department of Electronic and Information Engineering The Hong Kong Polytechnic University Aerospace information Research Institute Chinese Academy of Sciences

This paper studies the joint information transmission for an intelligent reflecting surface(IRS)aided single-input multiple-output(SIMO) communication system, where an IRS with discrete phase shifts aims to deliver its sensed information to the receiver, besides being a helper of the SIMO system. We first introduce the joint modulation strategy for delivering the information of the primary system and the IRS simultaneously. Specifically, the IRS modulates its information in both the received antenna index and the received signal phase; while the transmitter limits its signal phase in a small region to avoid aliasing. For the proposed strategy, we devise an IRS discrete phase shifts design to maximize the received signal power at the selected receive antenna. Then, we propose a receiver constellation design for the IRS’s and transmitter’s information to maximize the minimum Euclidean distance. Numerical results show that the proposed scheme is practical and competitive compared with several existing joint information transmission schemes.

关键词： IRS information transmission constellation design

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High voltage direct current transmission cables to help decarbonisation in Europe:Recent achievements and issues

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High Voltage 2022年第4期7卷 633-644页

作者： Giovanni Mazzanti department of Electrical Electronic and Information EngineeringUniversity of BolognaBolognaItaly

High Voltage Direct Current(HVDC)underground and submarine cables constitute an essential technology for the long-distance transmission of renewable electrical power with low losses,thereby fostering decarbonisation.In the past 2 decades,all this yielded a quasi-exponential rise of HVDC cable systems installed worldwide,but has also made the working conditions of HVDC cables harsher.In this paper,the contribution of HVDC cables to decarbonisation is tackled,with particular reference to the situation in Europe,and a few simple calculations showing in general terms the quantitative contribution provided by HVDC cable systems to decarbonisation are given.Then,the major issues towards long-lasting and reliable HVDC cable systems are summarised briefly,focussing-for the sake of brevity-on the influence of the main HVDC cable technologies,of cable laying environment and of duty service.Some hints are also provided at the chances given by multiterminal HVDC systems.

关键词： cable submarine thereby

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Multichannel adaptive signal detection: basic theory and literature review

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Science China(information Sciences) 2022年第2期65卷 5-44页

作者： Weijian LIU Jun LIU Chengpeng HAO Yongchan GAO Yong-Liang WANG Wuhan electronic information Institute department of electronic engineering and information Science University of Science and Technology of China State Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences School of electronic engineering Xidian University

Multichannel adaptive signal detection uses test and training data jointly to form an adaptive detector to determine whether a target exists. The resulting adaptive detectors typically possess constant false alarm rate(CFAR) properties; thus, no additional CFAR processing is required. In addition, a filtering process is also not required because the filtering function is embedded in the adaptive detector. Adaptive detection typically exhibits better detection performance than the filtering-then-CFAR detection technique.It has been approximately 35 years since the first multichannel adaptive detector was proposed by Kelly in 1986. However, there are few overview articles on this topic. Thus, in this study, we present a tutorial overview of multichannel adaptive signal detection with an emphasis on the Gaussian background. We discuss the main design criteria for adaptive detectors, investigate the relationship between adaptive detection and filtering-then-CFAR detection techniques, investigate the relationship between adaptive detectors and adaptive filters, summarize typical adaptive detectors, present numerical examples, provide a comprehensive literature review, and discuss potential future research tracks.

关键词： constant false alarm rate multichannel signal signal mismatch statistical distribution subspace signal

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Speed Regulation Method Using Genetic Algorithm for Dual Three-phase Permanent Magnet Synchronous Motors

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CES Transactions on Electrical Machines and Systems 2023年第2期7卷 171-178页

作者： Xiuhong Jiang Yuying Wang Jiarui Dong the department of School of electronic information engineering Shenyang Aerospace UniversityShenyang110136China

Dual three-phase Permanent Magnet Synchronous Motor(DTP-PMSM)is a nonlinear,strongly coupled,high-order multivariable system.In today’s application scenarios,it is difficult for traditional PI controllers to meet the requirements of fast response,high accuracy and good robustness.In order to improve the performance of DTP-PMSM speed regulation system,a control strategy of PI controller based on genetic algorithm is proposed.Firstly,the basic mathematical model of DTP-PMSM is established,and the PI parameters of DTP-PMSM speed regulation system are optimized by genetic algorithm,and the modeling and simulation experiments of DTP-PMSM control system are carried out by MATLAB/SIMULINK.The simulation results show that,compared with the traditional PI control,the proposed algorithm significantly improves the performance of the control system,and the speed output overshoot of the GA-PI speed control system is smaller.The anti-interference ability is stronger,and the torque and double three-phase current output fluctuations are smaller.

关键词： Dual three-phase permanent magnet synchronous motor Genetic algorithm PI control Speed regulation

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Image Blind Deblurring Using an Adaptive Patch Prior

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Tsinghua Science and Technology 2019年第2期24卷 238-248页

作者： Yongde Guo Hongbing Ma department of electronic engineering Tsinghua University department of electronic engineering Tsinghua University College of information Science and engineering Xinjiang University

Image blind deblurring uses an estimated blur kernel to obtain an optimal restored original image with sharp features from a degraded image with blur and noise artifacts. This method, however, functions on the premise that the kernel is estimated accurately. In this work, we propose an adaptive patch prior for improving the accuracy of kernel estimation. Our proposed prior is based on local patch statistics and can rebuild low-level features,such as edges, corners, and junctions, to guide edge and texture sharpening for blur estimation. Our prior is a nonparametric model, and its adaptive computation relies on internal patch information. Moreover, heuristic filters and external image knowledge are not used in our prior. Our method for the reconstruction of salient step edges in a blurry patch can reduce noise and over-sharpening artifacts. Experiments on two popular datasets and natural images demonstrate that the kernel estimation performance of our method is superior to that of other state-of-the-art methods.

关键词： blind deblurring adaptive patch prior kernel estimation low-level features internal patch information

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Achievement of Interference Alignment in General Underlay Cognitive Radio Networks: Scenario Classification and Adaptive Spectrum Sharing

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China Communications 2018年第6期15卷 98-108页

作者： Mei Rong Department of Electronic and Information Engineering Chang'an University

Interference alignment(IA) is suitable for cognitive radio networks(CRNs).However, in IA spectrum sharing(SS) process of general underlay CRNs, transmit power of cognitive radio transmitters usually should be reduced to satisfy interference constraint of primary user(PU), which may lead to low signalto-noise-ratio at cognitive radio receivers(CRRs). Consequently, sum rate of cognitive users(CUs) may fall short of the theoretical maximum through IA. To solve this problem,we propose an adaptive IA SS method for general distributed multi-user multi-antenna CRNs. The relationship between interference and noise power at each CRR is analyzed according to channel state information, interference requirement of PU, and power budget of CUs. Based on the analysis, scenarios of the CRN are classified into 4 cases, and corresponding IA SS algorithms are properly designed. Transmit power adjustment, CU access control and adjusted spatial projection are used to realize IA among CUs. Compared with existing methods, the proposed method is more general because of breaking the restriction that CUs can only transmit on the idle sub-channels. Moreover, in comparison to other five IA SS methods applicable in general CRN, the proposed method leads to improved achievable sum rate of CUs while guarantees transmission of PU.

关键词：收音机干扰光谱分类网络排列空间设计 CRN

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Mobile Jammer-Aided Secure UAV Communications via Trajectory Design and Power Control

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China Communications 2018年第8期15卷 141-151页

作者： An Li Wenjing Zhang department of electronic information engineering Nanchang University

To further promote the achievable average secrecy rate for UAV-ground communications, a UAV-aided mobile jamming strategy was proposed in this paper. Specifically, an additional cooperative UAV is employed as a mobile jammer to transmit the jamming signal to help keep the source UAV closer to the ground destination, thus establishing more favorable legitimate link and enhancing the secrecy performance. We aimed to maximize the achievable secrecy rate by jointly optimizing the trajectories and transmit power of both source UAV and jammer UAV. To solve the considered non-convex optimization problem, we presented a block coordinate descent based iterative algorithm to address a sequence of approximated convex problems for the optimized parameter block by block to find a local optimal solution. Numerical results verify that the proposed algorithm can achieve significant secrecy rate gain compared to all the benchmark schemes.

关键词：轨道设计 UAV 通讯 jammer 安全拥挤控制联合优化

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A Broad Learning-Driven Network Traffic Analysis System Based on Fog Computing Paradigm

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China Communications 2020年第2期17卷 1-13页

作者： Xiting Peng Kaoru Ota Mianxiong Dong department of information and electronic engineering Muroran Institute of Technology

The development of communication technologies which support traffic-intensive applications presents new challenges in designing a real-time traffic analysis architecture and an accurate method that suitable for a wide variety of traffic types.Current traffic analysis methods are executed on the cloud,which needs to upload the traffic data.Fog computing is a more promising way to save bandwidth resources by offloading these tasks to the fog nodes.However,traffic analysis models based on traditional machine learning need to retrain all traffic data when updating the trained model,which are not suitable for fog computing due to the poor computing power.In this study,we design a novel fog computing based traffic analysis system using broad learning.For one thing,fog computing can provide a distributed architecture for saving the bandwidth resources.For another,we use the broad learning to incrementally train the traffic data,which is more suitable for fog computing because it can support incremental updates of models without retraining all data.We implement our system on the Raspberry Pi,and experimental results show that we have a 98%probability to accurately identify these traffic data.Moreover,our method has a faster training speed compared with Convolutional Neural Network(CNN).

关键词： traffic analysis fog computing broad learning radio access networks

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Time and energy efficient data collection via UAV

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Science China(information Sciences) 2022年第8期65卷 182-196页

作者： Tianhao WANG Xiaowei PANG Jie TANG Nan ZHAO Xiuyin ZHANG Xianbin WANG School of information and Communication engineering Dalian University of Technology department of Electrical and Computer engineering Western University School of electronic and information engineering South China University of Technology

Using unmanned aerial vehicles(UAVs) for data collection has emerged as a promising technique to achieve both time-and energy-efficient data gathering while keeping data fresh. In this study, two schemes are proposed for flight cycle minimization and energy efficiency maximization to collect data from ground sensors. We first minimize the flight cycle by jointly optimizing the wake-up scheduling of sensors, the trajectory,and the time slot, which is a mixed-integer non-convex problem and difficult to solve directly. To this end,we propose an iterative algorithm based on block coordinate descent and successive convex approximation to decouple the original non-convex problem into two sub-problems and the constraints are turned to be convex approximately. Furthermore, the energy efficiency is maximized since the limited energy is a critical issue in UAV communication systems. We approximate the two subproblems as convex optimizations by introducing slack variables and applying SCA. The approximate energy efficiency is a fractional expression, and we use Dinkelbach’s method to solve it. Numerical results show that the flight cycle is minimized in the first scheme with the data requirement satisfied, while in the second scheme, the energy efficiency is maximized with the trade-off between the transmission data and the propulsion power consumption.

关键词： data collection energy efficiency maximization time minimization trajectory optimization unmanned aerial vehicle (UAV)

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