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Wideband channel measurement at 2.6 GHz using slippage correlation and amplitude distortion correction algorithm

Advances in Information Sciences and Service Sciences 2012年第18期4卷 387-394页

作者： Zhao, Min Wu, Muqing Guo, Song Hu, Qian Beijing Key Laboratory of Network System Architecture Convergence Beijing University of Posts and Telecommunications Beijing 100876 China

The measurement and analysis of wideband mobile channel are the foundations of network coverage and wireless network optimization. An outdoor propagation measurement campaign in which the sounding signal is PN sequence at 2.6GHz has been performed in beijing recently, and the result shows that slippage correlation based on PN sequence is capable to probe the channel impulse response (CIR). However, considering the inter-path interference that affects the result, an amplitude distortion correction algorithm is proposed to eliminate inter-path interference and enhance the accuracy of channel parameters. Moreover, results including the effect of the correction algorithm are analyzed and compared with that of traditional algorithm.

关键词： Impulse response

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Microplastics in road sediment of typical urban districts of beijing: Characteristics and risk assessment

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Process Safety and Environmental Protection 2025年 198卷

作者： Gu, Yuyang Zhang, Xiaoran Liu, Junfeng Deng, Jie Zhang, Ziyang Tan, Chaohong Li, Haiyan Hu, Yuansheng Key Laboratory of Urban Stormwater System and Water Environment Ministry of Education Beijing University of Civil Engineering and Architecture Beijing102616 China Department of Water Conservancy and Civil Engineering Beijing Vocational College of Agriculture Beijing102442 China Thermo Fisher Scientific Beijing100102 China UCD Dooge Centre for Water Resources Research School of Civil Engineering University College Dublin Belfield DublinD04 V1W8 Ireland

Microplastics (MP) in urban areas threaten ecosystems, causing water and soil contamination, as well as health risks. This study analyzed MP in road sediments from five areas in Daxing District, beijing. MP abundance ranged from 2060 ± 1143 items/kg to 8680 ± 3098 items/kg, with business areas having the highest levels, followed by traffic, residential, leisure, and cultural/educational areas. These differences are likely due to human activities, urbanization, and traffic. Most MP were fragmented, with polypropylene (PP) (43 %–87 %) and polyethylene (PE) (5 %–33 %) being the most common polymers. Fragmentation characteristics varied, with cultural/educational areas showing the highest α values despite fewer large MP. Lower λ values (2.80–5.00) suggest a higher potential for MP to break down, possibly contributing to stormwater pollution. Multiple risk assessments indicate that traffic and residential areas were classified as risk class IV (moderate to high pollution), while other areas were classified as risk class III (moderate pollution), based on the Pollution Load Index (PLI). The Polymer Risk Index (PRI) identified 60 % of functional areas as highest risk (level V) due to the prevalence of high-risk polymers like PP and PE. Frequent street cleaning may not be sufficient to remove smaller MP particles, which can persist in the environment. In contrast, leisure areas, with lower human activity, have a reduced risk of MP contamination. These findings can inform effective control measures for MP pollution in urban road sediments. © 2025 The Institution of Chemical Engineers

关键词： Risk assessment

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Improving high speed railway measured channel parameters centered at 2.6 GHz with the de-noise application based on wavelet transform

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Journal of Information and Computational Science 2014年第1期11卷 161-169页

作者： Yu, Deshui Xu, Chunxiu Zhao, Min Wang, Qian Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing 100876 China

In a wireless communication system for the high speed railway, system design engineers must have a thorough understanding of the radio-propagation characteristics, which is the essential aspect of wireless network designing and optimization. The channel impulse response can be generated by using slippage correlation measurement. Generally, the influence of the additive white Gaussian noise and the imperfect autocorrelation function is neglected, which will reduce the accuracy of the channel impulse response and the validity of the channel model. This paper proposes on a method which can eliminate the influence of the additive white Gaussian noise and the imperfect autocorrelation function through discrete wavelet transform. This method can provide a reliable guarantee to extract more accurate channel parameters, such as power delay profile, excess delay, and amplitude gain. And the results of simulation turn out that the de-noising method is effective. 1548-7741/Copyright © 2014 Binary Information Press.

关键词： Gaussian noise (electronic)

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EM wave propagation in non-uniform soil

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Information Technology Journal 2013年第19期12卷 5011-5016页

作者： Li, Li Dong, Na Chen, Jianya Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications 100876 Beijing China

As an emerging research field, Wireless Underground Sensor network (WUSN) is getting more and more focused these years because of its tremendous application benefit in agriculture, industry, military and so on. As the determinant of the performance of WUSN, the propagation characteristics of electromagnetic (EM) wave in the soil must be deeply investigated. Usually the soil is assumed ideal and uniform in existing works which results in a non-ignorable discrepancy to the reality of underground propagation. In this study, the propagation of EM wave in non-uniform soil is theoretically analyzed. Moreover, a novel simulation method for it based on Kriging interpolation and ADI-FDTD is proposed, based on which the propagation of 300 MHz EM wave in non-uniform soil is simulated and analyzed. The results expose the striking impact of non-homogeneity of the soil to the underground EM wave propagation performance which must be seriously taken into account when design and construct WUSNs. © 2013 Asian network for Scientific Information.

关键词： Electromagnetic waves

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Reduced frame set on wireless distorted video for quality assessment

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The Journal of China Universities of Posts and Telecommunications 2016年第4期23卷 77-82,100页

作者： Shao Hua Wen Xiangming Lu Zhaoming Chen Yawen Lu Jingyu Beijing Laboratory of Advanced Information Networks Beijing University of Posts and Telecommunications Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications

Objective video quality assessment methods often evaluate all the frames regardless of their importance. For wireless distorted videos, not every frame has the same contribution to the final overall quality due to the channel fading and interference, which may lead to the capacity variation in temporal. Besides, with the content similarity and error propagation pattern in temporal domain, it is possible to evaluate the overall quality with only part of the frames. In this paper, a demonstration is performed to show that the video quality can be evaluated with reduced frames set（RFS）, and a state transition model is proposed to extract the RFS. At last, a video quality assessment（VQA） method is carried out based on RFS. Compared with several state-of-the-art methods, our method can achieve a suitable accuracy with less frames to be processed.

关键词： VQA wireless distortion quality of experience

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Joint system consumption minimization and workload allocation in edge-core network

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The Journal of China Universities of Posts and Telecommunications 2018年第3期25卷 45-54页

作者： Wang Shaochun Lu Zhaoming Wen Xiangming Wang Luhan Ma Lu Beijing Laboratory of Advanced Information Networks Beijing University of Posts and Telecommunications Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications

The explosive increase of smart devices and mobile traffic results intolerable network latency and degraded service to the end-users. in heavy burden on backhaul and core network, As a complement to core network, edge network contributes to relieving network burden and improving user experience. To investigate the problem of optimizing the total consumption in an edge-core network, the system consumption minimization problem is fromulated, considering the energy consumption and delay. Given that the formulated problem is a mixed nonlinear integer programming （MNIP） , a low-complexity workload allocation algorithm is proposed based on interior-point method. The proposed algorithm has an extremely short running time in practice. Finally, simulation results show that edge network can significantly complement core network with much reduced backhaul energy consumption and delay.

关键词： edge network core network system consumption optimization workload allocation

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SWN: An SDN Based Framework for Carrier Grade WiFi networks

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China Communications 2016年第3期13卷 12-26页

作者： LEI Tao WEN Xiangming LU Zhaoming ZHAO Xing LI Yangchun ZHANG Biao Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing Laboratory of Advanced Information Networks Beijing University of Posts and Telecommunications

With the rapid growth of mobile data traffic and vast traffic offloaded from cellular network, Wi-Fi has been considered as an essential component to cope with the tremendous growth of mobile data traffic. Although operators have deployed a lot of carrier grade Wi-Fi networks, but there are still a multitude of arrears for nowadays Wi-Fi networks, such as supporting seamless handover between APs, automatic network access and unified authentication, etc. In this paper, we propose an SDN based carrier grade Wi-Fi network framework, namely SWN. The key conceptual contribution of SWN is a principled refactoring of Wi-Fi networks into control and data planes. The control plane has a centralized global view of the whole network, can perceive the underlying network state by network situation awareness(NAS) technique, and bundles the perceived information and network management operations into northbound Application Programming Interface(API) for upper applications. In the data plane, we construct software access point(SAP) to abstract the connection between user equipment(UE) and access point(AP). network operators can design network applications by utilizing these APIs and the SAP abstraction to configure and manage the whole network, which makes carrier grade Wi-Fi networks more flexible, user-friendly, and scalable.

关键词： SWN carrier grade Wi-Finet works SDN seamless handover load balancing Hotspot 2.0 traffic offloading

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Design of in-network caching scheme in CCN based on grey relational analysis

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The Journal of China Universities of Posts and Telecommunications 2014年第2期21卷 1-8页

作者： CUI Xian-dong HUANG Tao LIU Jiang LI Li CHEN Jian-ya LIU Yun-jie State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Future Network Industry Innovation Center of China

In-network caching is one of the most important issues in content centric networking （CCN）, which may extremely influence the performance of the caching system. Although much work has been done for in-network caching scheme design in CCN, most of them have not addressed the multiple network attribute parameters jointly during caching algorithm design. Hence, to fill this gap, a new in-network caching based on grey relational analysis （GRA） is proposed. The authors firstly define two newly metric parameters named request influence degree （RID） and cache replacement rate, respectively. The RID indicates the importance of one node along the content delivery path from the view of the interest packets arriving The cache replacement rate is used to denote the caching load of the node. Then combining hops a request traveling from the users and the node traffic, four network attribute parameters are considered during the in-network caching algorithm design. Based on these four network parameters, a GRA based in-network caching algorithm is proposed, which can significantly improve the performance of CCN. Finally, extensive simulation based on ndnSIM is demonstrated that the GRA-based caching scheme can achieve the lower load in the source server and the less average hops than the existing the betweeness （Betw） scheme and the ALWAYS scheme.

关键词： CCN in-network caching request influence degree cache replacement rate grey relational analysis

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Timely traffic identification on P2P streaming media

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The Journal of China Universities of Posts and Telecommunications 2012年第2期19卷 67-73页

作者： YANG Jie YUAN Lun HE Yang CHEN Lu-ying Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication EngineeringBeijing University of Posts and TelecommunicationsBeijing 100876China

Since the year of 2006, peer-to-peer （P2P） streaming media service has been developing rapidly, the user scale and income scale achieve synchronous growth. However, while people enjoying the benefits of the distributed resources, a great deal of network bandwidth is consumed at the same time. Research on P2P streaming traffic characteristics and identification is essential to Internet service providers （ISPs） in terms of network planning and resource allocation. In this paper, we introduce the current common P2P traffic detection technology, and analyze the payload length distribution and payload length pattern in one flow of four popular P2P streaming media applications. Combining with the deep flow inspection and machine learning algorithm, a nearly real-time The experiments proved that this approach can achieve a high identification approach for P2P streaming media is proposed. accuracy with low false positives.

关键词： deep flow inspection machine learning payload length distribution traffic identification

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Dynamic recovery for survivable virtual network embedding

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The Journal of China Universities of Posts and Telecommunications 2014年第3期21卷 77-84页

作者： LU Bo HUANG Tao SUN Xiao-chuan CHEN Jian-ya LIU Yun-jie Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications School of Information Engineering Hebei United University

network virtualization is a promising way to overcome the current ossification of the Intemet. It is essential challenge to find effective, efficient and robust embedding algorithms for recovering virtual network. The virtual network mapping algorithm based on integer programming which was proposed months ago. But it did consider the faults of physical network resources, which is so called survivable virtual network embedding （VNE） problem. Previous strategies for enabling survivability in network virtualization focused on providing protection for the physical network or enhancing the virtual networks by providing backup physical resources in advance, and treated all the physical failures as link failures. In the article, a dynamic recovery method is proposed to solve the survivable virtual network embedding problem based on the integer programming VNE algorithm. The dynamic recovery method doesn＇t need to backup physical resources and it makes more substrate resources which can be used in the embedding. The dynamic recovery process will be activated only when physical failures occur. Different algorithms are used to recovery node and link failures. Simulations show that the method helps to recover almost all of physical failures by finding the substitute nodes and paths, and its performance is very close to that of pure VNE method without considering physical failures.

关键词： network virtualization integer programming survivable virtual network embedding dynamic recovery

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