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Achievable Rate Analysis and Optimization of Double-RIS Assisted Spatially Correlated MIMO with Statistical CSI

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China communications 2025年第1期22卷 139-157页

作者： Xu Kaizhe Guo Jiajia Zhang Jun Jin Shi Ma Shaodan department of communications and Networking Xi’an Jiaotong-Liverpool UniversitySuzhou 215123China State Key Laboratory of Internet of Things for Smart City University of MacaoMacao SARChina Jiangsu Key Laboratory of Wireless communications Nanjing University of Posts and TelecommunicationsNanjing 210003China National Mobile communications Research Laboratory Southeast UniversityNanjing 210096China State Key Laboratory of Internet of Things for Smart City and the department of Electrical and Computer Engineering University of MacaoMacao SARChina

Reconfigurable intelligent surface(RIS)is a novel meta-material which can form a smart radio environment by dynamically altering reflection directions of the impinging electromagnetic *** the prior literature,the inter-RIS links which also contribute to the performance of the whole system are usually neglected when multiple RISs are *** this paper we investigate a general double-RIS assisted multiple-input multiple-output(MIMO)wireless communication system under spatially correlated non line-of-sight propagation channels,where the cooperation of the double RISs is also *** design objective is to maximize the achievable ergodic rate based on full statistical channel state information(CSI).Specifically,we firstly present a closedform asymptotic expression for the achievable ergodic rate by utilizing replica method from statistical *** a full statistical CSI-enabled optimal design is proposed which avoids high pilot training overhead compared to instantaneous CSI-enabled *** further reduce the signal processing overhead and lower the complexity for practical realization,a common-phase scheme is proposed to design the double *** results show that the derived asymptotic ergodic rate is quite accurate even for small-sized antenna *** the proposed optimization algorithm can achieve substantial gain at the expense of a low overhead and ***,the cooperative double-RIS assisted MIMO framework is proven to achieve superior ergodic rate performance and high communication reliability under harsh propagation environment.

关键词： common reflection pattern double RISs large system analysis MIMO replica method

Interferometric orbit determination for geostationary satellites

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Science China(Information Sciences) 2017年第6期60卷 22-32页

作者： Roger M.FUSTER Marc FERNNDEZ USóN Antoni BROQUETAS IBARS Remote Sensing Laboratory Department of Signal and Communications TheoryUniversitat Politècnica de Catalunya

Future Geo SAR missions are expected to provide higher resolution radar images featuring shorter revisit times by locating a radar payload on-board of a geostationary satellite. One of the main challenges in Geo SAR processing is accurately determining the satellite orbit to obtain a precise phase history, in order to properly focus the retrieved data. To tackle this challenge, a multiple baseline ground-based interferometer is proposed as a compact and reliable method to achieve an unprecedented accuracy. As a proof of concept, this paper presents the results obtained from a single baseline prototype, whose results can be extrapolated to a larger system, able to be used in future missions.

关键词： GeoSAR interferometry orbit determination geostationary SAR

Localizing base stations with measured data:a concatenated image-based deep learning approach

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Science China(Information Sciences) 2025年第2期68卷 385-386页

作者： Yang CHEN Ziyuan LIU Feng JIANG Hong SHEN Wei XU Mengyu LI Ritao CHENG National Mobile communications Research Laboratory Southeast University China Mobile Group Design Institute Co. Ltd.

Localization has become an indispensable function of modern cellular communication systems [1]. In a cloud radio access network(C-RAN), the remote radio head(RRH) is the actual signal transmitter, whose location can assist in wireless network layout optimization and wireless resource management. The measurement of the RRH location can only be done manually on-site due to the lack of global positioning systems(GPS) at the RRH side, which is thus not a cost-effective solution for the widely used C-RAN with a large number of RRH units.

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Improved organs at risk segmentation based on modified U‐Net with self‐attention and consistency regularisation

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CAAI Transactions on Intelligence Technology 2024年第4期9卷 850-865页

作者： Maksym Manko Anton Popov Juan Manuel Gorriz Javier Ramirez Electronic Engineering department Igor Sikorsky Kyiv Polytechnic InstituteKyivUkraine department of signal theory Telematics and CommunicationsUniversity of GranadaGranadaSpain

Cancer is one of the leading causes of death in the world,with radiotherapy as one of the treatment *** planning starts with delineating the affected area from healthy organs,called organs at risk(OAR).A new approach to automatic OAR seg-mentation in the chest cavity in Computed Tomography(CT)images is *** proposed approach is based on the modified U‐Net architecture with the ResNet‐34 encoder,which is the baseline adopted in this *** new two‐branch CS‐SA U‐Net architecture is proposed,which consists of two parallel U‐Net models in which self‐attention blocks with cosine similarity as query‐key similarity function(CS‐SA)blocks are inserted between the encoder and decoder,which enabled the use of con-sistency *** proposed solution demonstrates state‐of‐the‐art performance for the problem of OAR segmentation in CT images on the publicly available SegTHOR benchmark dataset in terms of a Dice coefficient(oesophagus-0.8714,heart-0.9516,trachea-0.9286,aorta-0.9510)and Hausdorff distance(oesophagus-0.2541,heart-0.1514,trachea-0.1722,aorta-0.1114)and significantly outperforms the *** current approach is demonstrated to be viable for improving the quality of OAR segmentation for radiotherapy planning.

关键词： 3‐D computer vision deep learning deep neural networks image segmentation medical image processing object segmentation

Dynamic Collaborative Data Download in Heterogeneous Satellite Networks

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China communications 2025年第2期22卷 26-46页

作者： Wu Qi Li Xintong Zhu Lidong National Key Laboratory of Wireless communications University of Electronics of Science and Technology of ChinaChengdu 611731China

Low-earth-orbit(LEO)satellite network has become a critical component of the satelliteterrestrial integrated network(STIN)due to its superior signal quality and minimal communication ***,the highly dynamic nature of LEO satellites leads to limited and rapidly varying contact time between them and Earth stations(ESs),making it difficult to timely download massive communication and remote sensing data within the limited time *** address this challenge in heterogeneous satellite networks with coexisting geostationary-earth-orbit(GEO)and LEO satellites,this paper proposes a dynamic collaborative inter-satellite data download strategy to optimize the long-term weighted energy consumption and data downloads within the constraints of on-board power,backlog stability and time-varying ***,the Lyapunov optimization theory is applied to transform the long-term stochastic optimization problem,subject to time-varying contact time and on-board power constraints,into multiple deterministic single time slot problems,based on which online distributed algorithms are developed to enable each satellite to independently obtain the transmit power allocation and data processing decisions in ***,the simulation results demonstrate the superiority of the proposed scheme over benchmarks,e.g.,achieving asymptotic optimality of the weighted energy consumption and data downloads,while maintaining stability of the on-board backlog.

关键词： backlog stability data download heterogeneous satellite networks Lyapunov optimization power allocation

Coherent ONU based on 850 μm-long cavity-RSOA for next-generation ultra-dense access network

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Chinese Optics Letters 2016年第5期14卷 19-23页

作者： Guang Yong Chu Adolfo Lerín Iván N.Cano Victor Polo Josep Prat department of signal theory and communications Universitat Politècnica de Catalunya

In this Letter, an efficient bidirectional differential phase-shift keying （DPSK）--DPSK transmission for a ultra- dense wavelength division-multiplexed passive optical network is proposed. A single distributed feedback laser at the optical network unit （ONU） is used both as the local laser for downlink coherent detection and the optical carrier for uplink. Phase-shift keying is generated using a low-cost reflective semiconductor optical amplifier （RSOA） at the ONU. The RSOA chip has the bandwidth of 4.7 GHz at the maximum input power and bias current. For uplink transmission, the sensitivity of the RSOA chip reaches -48.2 dBm at the level of bit error rate = 10^-3 for back-to-back, and the penalty for 50 km transmission is less than 1 dB when using polarization diversity.

关键词： ONU RSOA Coherent ONU based on 850 m-long cavity-RSOA for next-generation ultra-dense access network

Weak feedback self-mixing interference fringe slope discrimination method based on deep learning

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Optoelectronics Letters 2025年

作者： ZHAO Yan LIN Maohua DU Shengzhi TONG Jigang LIU Bin HAN Fangfang School of Electrical Engineering and Automation， Tianjin University of Technology Tianjin Key Laboratory for Control theory and Applications in Complicated Systems department of Electrical Engineering， Tshwane University of Technology

In order to identify the tilt direction of the self-mixing interference (SMI) signals under weak feedback regime interfered by noise， a deep learning method is proposed. The one-dimensional U-Net (1D U-Net) neural network can discriminate the direction of self-mixing fringes accurately and quickly. For experimental SMI signals， the 1D U-Net can be used for discriminant direction after a one-step normalization. Simulation and experimental results show that the proposed method is suitable for SMI signals with noise within the whole weak feedback regime， and can maintain a high discrimination accuracy for signals interfered by 5dB noise. Combined with fringe counting method， accurate and rapid SMI signal displacement reconstruction can be realized.

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Impact of Optical Hop Constraints on the IP/MPLS-over-WSON Networks CAPEX

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China communications 2015年第11期12卷 112-118页

作者： LIU Fengqing Jaume Comellas School of Opto-Electronic Engineering Nanjing University of Posts and Telecommunications Dept.of signal theory and communications Universitat Politècnica de Catalunya Barcelona

In this work,the impact of hop constraints on the CAPEX of multi-layer IP/MPLS over WSON networks is evaluated under different scenarios. By routing lightpaths with different number of transparent hops,the cost of networks varies significantly. This effect is thoroughly analyzed with a heuristic algorithm for different network topologies belonging to some European network operators. The main conclusion extracted is that limiting the transparent reach in such multi-layer networks can give a good tradeoff between CAPEX of IP/MPLS networks and WSON networks,and even lead to signifi cant savings in CAPEX when compared to longer lightpaths routing strategies.

关键词： IP/MPLS over WSON networks optical hop constraints CAPEX heuristics

signal acquisition of brain-computer interfaces:A medical-engineering crossover perspective review

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Fundamental Research 2025年第1期5卷 3-16页

作者： Yike Sun Xiaogang Chen Bingchuan Liu Liyan Liang Yijun Wang Shangkai Gao Xiaorong Gao department of Biomedical Engineering Tsinghua UniversityBeijing 100084China Institute of Biomedical Engineering Chinese Academy of Medical Sciences and Peking Union Medical CollegeTianjin 300192China Center for Intellectual Property and Innovation Development China Academy of Information and Communications TechnologyBeijing 100161China Institute of Semiconductors Chinese Academy of SciencesBeijing 100083China

Brain-computer interface(BCI)technology represents a burgeoning interdisciplinary domain that facilitates direct communication between individuals and external *** efficacy of BCI systems is largely contingent upon the progress in signal acquisition *** paper endeavors to provide an exhaustive synopsis of signal acquisition technologies within the realm of BCI by scrutinizing research publications from the last ten *** review synthesizes insights from both clinical and engineering viewpoints,delineating a comprehensive two-dimensional framework for understanding signal acquisition in *** delineate nine discrete categories of technologies,furnishing exemplars for each and delineating the salient challenges pertinent to these *** review furnishes researchers and practitioners with a broad-spectrum comprehension of the signal acquisition landscape in BCI,and deliberates on the paramount issues presently confronting the *** enhancements in BCI signal acquisition should focus on harmonizing a multitude of disciplinary *** equilibrium between signal fidelity,invasiveness,biocompatibility,and other pivotal considerations is *** doing so,we can propel BCI technology forward,bolstering its effectiveness,safety,and depend-ability,thereby contributing to an auspicious future for human-technology integration.

关键词： Brain-computer interface signal acquisition technologies Surgery Detection Human computer interaction