检索结果-内蒙古大学图书馆

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

作者： Ning Cao Ziyuan Zheng Wenpeng Jing Zhaoming Lu Xiangming Wen Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China Beijing Laboratory of Advanced Information Networks Beijing University of Posts and Telecommunications Beijing China

Low Earth Orbit (LEO) satellite communication (SatCom) is considered a promising solution to supplement terrestrial networks. However, line-of-sight (LoS) links between the satellite and terrestrial terminals are possibly blocked by objects on Earth (e.g., mountains, tall buildings, etc.), leading to communication interruptions. This paper introduces Reconfigurable Intelligent Surface (RIS) into the LEO SatCom system to extend satellite coverage in blockage scenarios. Specifically, in contrast to the signal transmission model under the far-field assumption in usual studies, we present a model combining the near-field and far-field of the RIS, which can characterize the operational differences of each reflecting element more accurately. Next, a user-received power maximization problem is formulated and we solve it by jointly optimizing the RIS phase shifts and orientation. Simulation results demonstrate the effectiveness of the proposed optimization algorithm. Remarkably, it is shown that the scheme based on the proposed algorithm can assist the satellite in extending its coverage and providing higher power than that before blockage occurs compared to the baseline schemes.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Atmospheric Ducting Effect in Wireless Communications:Challenges and Opportunities

引用

Journal of Communications and Information networks 2021年第2期6卷 101-109页

作者： Fangfang Liu Jiaxi Pan Xiangwei Zhou Geoffrey Ye Li Beijing Laboratory of Advanced Information Networks Beijing Key Laboratory of Network System Architecture and ConvergenceBeijing University of Posts and TelecommunicationsBeijing 100876China Louisiana State University Baton Rouge LA 70803USA Imperial College London London SW72AZU.K.

Atmospheric ducting has a significant impact on electromagnetic wave *** signals that are trapped and guided by the atmospheric duct can travel a much longer distance over the horizon with lower attenuation since the signal power does not spread isotropically through the *** ducting brings both challenges and opportunities to wireless *** one hand,the signals propagating in the atmospheric duct may interfere with a receiver far away as remote co-channel *** the other hand,a point-to-point link can be established directly through the atmospheric duct to enable beyond line-of-sight *** this article,the formation of the atmospheric duct and its effects on radio wave propagation are first *** solutions and standardization activities in the 3rd Generation Partnership Project(3GPP)to mitigate atmospheric duct induced remote interference are ***,the applications and design challenges of atmospheric duct enabled beyond line-of-sight communications are reviewed and future research directions are suggested.

关键词： atmospheric duct ducting channel modeling beyond line-of-sight remote interference management

来源：评论

学校读者我要写书评

暂无评论

An Energy-Efficient Beam Hopping Strategy in Interference Coexistence Satellite systems

An Energy-Efficient Beam Hopping Strategy in Interference Co...

引用

IEEE International Conference on Communications in China Workshops (ICCC)

作者： Hao Sun Wenpeng Jing Zhaoming Lu Xiangming Wen Wei Li Beijing Key Laboratory of Network System Architecture and Convergence Beijing Laboratory of Advanced Information Networks Beijing University of Posts and Telecommunications Beijing China Satellite Frequency and Orbit Resource Research Center The State Radio Monitoring Center Beijing China

ISBN: (数字)9798350377675

ISBN: (纸本)9798350377682

While beam hopping (BH) has revolutionized satel-lite communication by addressing non-uniform traffic demands and minimizing beam interference, existing research on multi-satellite BH scenarios often overlooks energy efficiency (EE) optimization. This can lead to increased operational costs and reduced satellite lifespans due to higher onboard energy consumption. In this paper, we propose a novel energy-efficient beam hopping strategy in the coexistence scenario of geosynchronous orbit (GSO) and non-geosynchronous orbit (NGSO) satellite systems. Specifically, the proposed strategy can both balance traffic load among NGSO satellites and avoid interference to GSO ground stations. A joint multi-satellite BH optimization problem is formulated to optimize a trade-off function between quality of service (QoS) and EE for the NGSO system. Then, the original problem is divided into the satellite-cell assignment, BH pattern design, and beam power allocation sub-problems and solved sequentially. The numerical results demonstrate the superiority of the proposed strategy in enhancing the QoS and EE of the NGSO system while effectively mitigating interference with the GSO system.

关键词： Energy consumption Satellites Interference Quality of service Telecommunication traffic Energy efficiency Orbits Resource management Optimization Satellite communications

来源：评论

学校读者我要写书评

暂无评论

Adversarial Samples Defense Strategy Based on Service Orchestration

Adversarial Samples Defense Strategy Based on Service Orches...

引用

International Conference on Computer and Communications (ICCC)

作者： Mengxin Zhang Xiaofeng Qiu Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

Deep neural networks (DNNs) are playing an increasingly significant role in the modern world. However, they are weak to adversarial samples that are generated by adding specially crafted perturbations. Most defenses against adversarial samples focused on refining the DNN models, which often sacrifice the performance and computational cost of models on benign samples. In this paper, we propose a manifold distance detection method to distinguish legitimate samples and adversarial samples by measuring the different distances on the manifold. The manifold distance detection method neither modifies the protected models nor requires knowledge of the process for generating adversarial samples. Inspired by the effectiveness of the manifold distance detection, we demonstrated a well-designed orchestrated defense strategy, named Manifold Distance Judge (MDJ), which selects the best image processing method that will effectively expand the manifold distance between legitimate and adversarial samples, and thus, enhances the performance of the following manifold distance detection method. Tests on the ImageNet dataset, the MDJ is effective against the most adversarial samples under white-box, gray-box, and black-box attack scenarios. We show empirically that the orchestration strategy MDJ is significantly better than Feature Squeezing on the recall rate. Meanwhile, MDJ achieves high detection rates against CW attack and DI-FGSM attack.

关键词： Manifolds Deep learning Computational modeling Perturbation methods Image processing Refining Neural networks

来源：评论

学校读者我要写书评

暂无评论

Fast Beam Switching Based on Machine Learning for MmWave Massive MIMO systems 3rd

Fast Beam Switching Based on Machine Learning for MmWave Mas...

引用

3rd EAI International Conference on Artificial Intelligence for Communications and networks, AICON 2021

作者： Chen, Kean Liu, Danpu He, Xingwen Beijing Laboratory of Advanced Information Networks Beijing China Beijing Key Laboratory of Network System Architecture and Convergence Beijing China Beijing University of Posts and Telecommunications Beijing100876 China

ISBN: (纸本)9783030901950

Millimeter wave (mmWave) and massive multiple-input-multiple-output (MIMO) systems are two key technologies for 5G. Beamforming based on massive MIMO can produce high directional beams with array gain, and thus effectively compensate for the high path loss of mmWave. As the number of antennas increases, the beams become increasingly narrow, resulting in large overhead and high latency in the initial access and handover of the beams. For high-speed mobile scenarios, beam switching becomes more challenging since the traversal search among a large number of beams cannot be completed in a short period of time. To address this problem, this paper proposes a method based on machine learning to predict the optimal Base Station (BS) and the optimal beam pair at the successive instant for the User Equipment (UE) in motion. More specifically, a Random Forest (RF) classification model is trained to learn the channel’s features in a multi-cell scenario, and complete the nonlinear modeling of the propagation environment. Furthermore, this model is used to predict the future optimal BS and the optimal beam pair for a moving UE based on the present UE’s location, BS beam index and RSRP value. The simulation results show that the prediction accuracy is greater than 90% in most situations, thus the latency and the consumption of signaling resources for beam switch is reduced significantly while the loss in spectral efficiency is little. © 2021, ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering.

关键词： Machine learning

来源：评论

学校读者我要写书评

暂无评论

Information Bottleneck Guided Joint Source-Channel Coding with HARQ

Information Bottleneck Guided Joint Source-Channel Coding wi...

引用

2025 IEEE Wireless Communications and networking Conference, WCNC 2025

作者： Zhang, Haoxuan Sun, Lunan Guo, Caili Yang, Yang School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing Key Laboratory of Network System Architecture and Convergence Beijing100876 China School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing Laboratory of Advanced Information Networks Beijing100876 China

ISBN: (纸本)9798350368369

Deep joint source-channel coding (JSCC) with hybrid automatic repeat request (HARQ) for image transmission has attracted increasing attention due to its flexibility and high efficiency. Existing researches mainly focus on minimizing the distortion of mutiple retransmissions while ignoring the redundancy in retransmitted signal and such redundancy may lead bandwidth waste and reconstruction quality degradation. In this paper, we propose an information bottleneck (IB) guided deep JSCC with HARQ system (HARQ-IBJSC), which aims at improving the reconstruction quality by compressing the redundancy in retransmitted signal. In particular, we first design a new IB objective for deep JSCC with HARQ system, which simultaneously reduces redundancy in the retransmitted signal and minimizes image transmission distortion. Since the mutual information terms in the designed IB objective is intractable, we then derive a differentiable lower bound on the IB objective and use the bound as the loss function of HARQ-IBJSC. Experimental results show that the proposed HARQ-IBJSC system can increase PSNR by up to 1 dB. © 2025 IEEE.

关键词： Image coding

来源：评论

学校读者我要写书评

暂无评论

SINR-Adaptive and CBR-Controllable Semantic Cellular Communication Considering Imperfect CSI and Inter-Cell Co-channel Interference

引用

IEEE Transactions on Cognitive Communications and networking 2024年

作者： Niu, Haiwen Wang, Luhan Lu, Zhaoming Wu, Celimuge Wen, Xiangming Beijing University Of Posts And Telecommunications Beijing Key Laboratory Of Network System Architecture And Convergence Beijing Laboratory Of Advanced Information Networks Beijing100876 China The University Of Electro-Communications Meta-Networking Research Center 1-5-1 Chofugaoka Chofu-shi Tokyo182-8585 Japan

Deep learning (DL)-enabled semantic communications offer promising prospects for higher data transmission efficiency. However, most existing studies focus on point-to-point transmissions with perfect channel state information (CSI) and fixed channel bandwidth ratio (CBR). This paper investigates multi-point transmission in cellular networks with spectrum resource sharing and proposes a signal-to-interference plus noise ratio (SINR) adaptive and CBR-controllable semantic cellular communication system (SACC). In this system, we design a semantic encoder by a Transformer-convolutional neural network (CNN) mixture block to capture non-local and local latent image features simultaneously and a SINR-adaptive module based on the channel-spatial soft attention mechanism to scale image features according to SINR conditions. A model adaption strategy is proposed to handle varying inter-cell co-channel interference proportions under the same SINR. Additionally, a semantic-channel encoder-decoder forwarding paradigm, termed semantic translation, enables dynamic networking among intra-cell users. Extensive simulation results show that the proposed SACC achieves graceful degradation and better image reconstruction performance versus the current engineered "JPEG+LDPC+QAM"and DeepJSCC benchmarks across different wireless environments and CBRs. Furthermore, experimental results demonstrate substantial improvements in FLOPs, model sizes, and computing latency over the state-of-the-art ADJSCC and WITT with comparable performance. © 2015 IEEE.

关键词： Bandwidth

来源：评论

学校读者我要写书评

暂无评论

Performance Optimization for Task-Oriented Communications

Performance Optimization for Task-Oriented Communications

引用

IEEE International Conference on Communications (ICC)

作者： Chuanhong Liu Caili Guo Yang Yang Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing China Beijing Laboratory of Advanced Information Networks School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing China

ISBN: (数字)9781728190549

ISBN: (纸本)9781728190556

Task-oriented communication is a new paradigm that aims at providing efficient connectivity for accomplishing intelligent tasks rather than the reception of every transmitted bit. This paper proposes a deep learning-based task-oriented communication architecture for end-to-end (E2E) semantics transmission, where extracted semantics is compressed by the proposed adaptable semantic compression (ASC) method. However, accommodating multiple users in a delay-intolerant system poses a challenge. Higher compression ratios conserve channel re-sources but cause semantic distortion, while lower ratios demand more resources and may lead to transmission failure due to delay constraints. To address this, we optimize both compression ratio and resource allocation to maximize task success probability. Specifically, due to the nonconvexity of the problem, we propose a compression ratio and resource allocation (CRRA) algorithm that separates the problem into two subproblems and solving them iteratively. Simulation results show that the proposed algorithm can obtain at least 14.3% success gains over baseline algorithms.

关键词： Power measurement Communication systems Simulation Semantics Collaboration Distortion Delays

来源：评论

学校读者我要写书评

暂无评论

WiLink: Link Selection-Based 3D Human Pose Estimation Using Commodity Wi-Fi

WiLink: Link Selection-Based 3D Human Pose Estimation Using ...

引用

IEEE Conference on Wireless Communications and networking

作者： Liming Wang Lingchao Guo Zhaoming Lu Xiangming Wen Shuang Zhou Beijing Key Laboratory of Network System Architecture and Convergence Beijing Laboratory of Advanced Information Networks Beijing University of Posts and Telecommunications Beijing China China Academy of Information and Communications Technology Beijing China

Previous works have verified the feasibility of WiFi-based human pose estimation (HPE). However, their crucial limitations lie in requiring favorable placement of Wi-Fi devices and only sensing human poses in a small area. To address these issues, we propose WiLink, a Wi-Fi-based 3D HPE system that selectively uses several existing Wi-Fi links to achieve accurate HPE everywhere indoors. We find that the Channel State Information (CSI) fluctuations caused by human pose changes over different Wi-Fi links are various. According to the effectiveness of Wi-Fi links for human pose sensing, we classify the links as Noise-Dominated Links, Most-Effective Links and Redundant Links. Then we propose a Dynamic Link Selection (DLS) mechanism to adaptively select Most-Effective Links for HPE. This process maximizes the importance and minimizes the redundancy of the selected links. Finally, we feed the CSI samples corresponding to Most-Effective Links into a neural network to estimate human poses. Intensive experiments are conducted, and the results show that WiLink achieves a good performance in the scenario with multiple available Wi-Fi links.

关键词： Training Three-dimensional displays Fluctuations Pose estimation Redundancy Neural networks Sensors

来源：评论

学校读者我要写书评

暂无评论

Towards Expanding Precise Timing for Collaborative Its with Deterministic Communications in 6G

Towards Expanding Precise Timing for Collaborative Its with ...

引用

IEEE Conference on Wireless Communications and networking

作者： Hongxing Li Haotian Li Qianhan Gao Guochu Shou Yaqiong Liu Zhigang Guo Yihong Hu State Key Laboratory of Networking and Switching Technology School of Computer Science (National Pilot Software Engineering School) Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing China

ISBN: (数字)9798350368369

ISBN: (纸本)9798350368376

The demand for precise timing continues to grow with the rapid development of smart cities, where intelligent transportation emerges as a critical application heavily dependent on accurate time distribution. Deterministic communication is anticipated to be a defining feature of nextgeneration mobile networks (6G), enabling end-to-end timecritical applications, and unlocking new possibilities for achieving end-to-end precise time synchronization as well. To cope with the challenge of delivering precise time synchronization across broader areas at a lower cost, this paper proposes a method to achieve end-to-end precise time synchronization by leveraging the deterministic characteristics of communication networks. Specially, the proposed approach adopts the Software-Defined networking (SDN) paradigm to implement deterministic networking for the seamless integration of Time-Sensitive networking (TSN) and cellular networks. Furthermore, to mitigate the impact of wireless channel uncertainties on synchronization accuracy, we propose a network delay measurement mechanism based on the principle of time redundancy, designed to reduce end-to-end network delay variation. Experimental results validate the effectiveness of the proposed method, demonstrating its capability to constrain the end-to-end relative time error of wired and wireless converged networks to the microsecond scale, without necessitating modifications to the existing network infrastructure.

关键词： 6G mobile communication Wireless communication Cellular networks Uncertainty Accuracy Measurement uncertainty Transportation Delays Synchronization Software defined networking

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：