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International Conference on Telecommunications (ICT)

作者： Fan Zhang Tao Luo Jianfeng Li Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China Beijing University of Posts and Telecommunications Beijing Beijing CN

In this paper, we propose an efficient multi-hop broadcast routing algorithm based on Real-time Traffic Estimation in vehicular ad-hoc networks (VANETs) including a novel relay node selection scheme and an efficient adaptive rebroadcast wait delay strategy. Firstly, we take the overall traffic information into consideration to select the relay node, which is different with the traditional scheme only considering the distance information. In order to obtain more accurate traffic information in the target road segment, we employ the real-time traffic estimates algorithm to predict the information. Furthermore, we also reduce the rebroadcast waiting just select only one rebroadcast node by considering many influence factors such as the traffic density and the vehicle information. Therefore, a weighted utility function (WUF) is formulated to comprehensively consider the effect of these factors. Furthermore, the value of WUF can also be utilized to determine the waiting time of the rebroadcast node to achieve the adaptive wait scheme. Finally, the timeout retransmission strategy is employed to improve the reliability of broadcast message transmission at the source node. Theoretical and simulation results demonstrate the effectiveness of the proposed algorithm in terms of the packet delay, data redundancy, effective permeability and network robustness, when compared with classical M-Flood and Slotted algorithms.

关键词： Vehicles Routing Delays Prediction algorithms Algorithm design and analysis Real-time systems Reliability

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Broadcasting based neighborhood cooperative caching for content centric ad hoc networks

Broadcasting based neighborhood cooperative caching for cont...

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IEEE International Conference on Communications in China (ICCC)

作者： Le Zhou Tiankui Zhang Xiaogeng Xu Zhimin Zeng Yinlong Liu Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China Institute of Information Engineering Beijing CA China

Content centric networking is a promising technology for data dissemination, which can be used in wireless ad hoc networks to cope with short-lived connectivity and dynamic topologies in wireless environments. Meanwhile, the broadcast nature of radio channel can be leveraged to improve the cooperative cache gain of content centric ad hoc networks. In this paper, a broadcasting based neighborhood cooperative caching (BNC) strategy is proposed. In BNC, a node selects caching node among its adjacent nodes and informs its caching node to cache the content while forwarding the data packet. By making best of the broadcast nature of radio channel, BNC achieves neighborhood cooperative caching without occupying extra wireless channel resource. In addition, the method of topology potential is exploited to make caching decision among adjacent nodes. Simulation results show that BNC can lead to better utilization of network cache space without deteriorating the network performances.

关键词： Topology Ad hoc networks network topology Cooperative caching Wireless communication Broadcasting Next generation networking

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Self-adaptive genetic algorithm for LTE backhaul network

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Journal of networks 2014年第3期9卷 682-688页

作者： Li, Li Song, Hui Chen, Jianya Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

Mobile communication evolution from 2G, 3G to LTE shows a broadband and IP-oriented trend and the architecture of LTE backhaul network turns to be flat. In order to fit these new features, layer 3 routing technology has to be adopted in backhaul network and needs to be modified to fit it. In this paper, a new algorithm, named Self-Adaptive Genetic Algorithm (SAGA), is proposed to meet the demand of providing a highly efficient and QoS guaranteed routing scheme for LTE backhaul network. It can be used in Open Shortest Path First protocol (OSPF) as the core path selection algorithm. It is based on traditional genetic algorithm(GA) but improves the population initialization process in it as well as proposes a new fitness calculation function for it. Simulation verifies it can balance not only the traffic of network but also the load of MME pools, which improves the utility efficiency of the whole network. © 2014 ACADEMY PUBLISHER.

关键词： Quality of service

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Generalized dominating set based cooperative caching for content centric ad hoc networks

Generalized dominating set based cooperative caching for con...

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IEEE International Conference on Communications in China (ICCC)

With the growth of smartphone users, peer-to-peer ad hoc networks has become a potent complementary to content dissemination. Content centric networking (CCN) has been demonstrated as a promising fundamental driver for ad hoc networks to enhance the content dissemination. However, most of the existing CCN caching strategies are designed with the assumption that users are located at the edge of the network, which are less effective when migrated to ad hoc networks. Additionally, the battery capacity and cache space of nodes in ad hoc networks are limited. Considering the aforementioned distinctions, a generalized dominating set based cooperative caching placement strategy (GDSC) is proposed. Accordingly, the analytical model of GDSC is developed and the expressions of miss probability, average round trip hops and power consumption are derived. The simulation results validate the effectiveness of the GDSC strategy for content centric ad hoc networks, and show that GDSC achieves better compromise between cache cost and content retrieval time with lower power consumption by selecting appropriate nodes to deploying caches in ad hoc networks.

关键词： Ad hoc networks Power demand network topology Cooperative caching Topology Servers Next generation networking

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A recyclable platform-tolerant RFID tag antenna with cross-plane loop-fed

A recyclable platform-tolerant RFID tag antenna with cross-p...

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International RF and Microwave Conference, RFM

作者： Weijun Hong Yang Fu Qing Chen Li Deng Xiong Xiong Beijing Key Lab. of Network System Architecture and Convergence Beijing Univ. of Posts and Telecommunications Beijing China

ISBN: (纸本)9781467381710

To avoid performance fluctuation of radio frequency identification (RFID) system while the tag is attached on objects with different materials, a platform-tolerant UHF RFID tag antenna with stable high gain is proposed in this paper. The antenna is composed of an upper layer feeding loop and a lower layer planar dipole. Inductively coupling approach is adopted to feed, so that large mutual inductance could be introduced into the incident impedance of antenna, which enables great match between RFID chip and antenna. The coupling feeding method can also significantly decrease the impact on antenna impedance due to the introduced parallel capacity between radiation plane and platform. The realized results show that the antenna has an impedance bandwidth (S112 plate of aluminum, paper, copper, glass and air to be the platform, during these experiments the antenna gain varies less than 1dB. Compared with other cavity backed antenna or AMC, EBG based antenna, the antenna proposed in this paper has higher gain with an extremely simple structure which performs significant advantage for mass production.

关键词： Dipole antennas Impedance Antenna feeds RFID tags UHF antennas

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Energy Efficient Handover Algorithm in OFDMA systems

Energy Efficient Handover Algorithm in OFDMA Systems

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2015 IEEE International Conference on Computer and Communications(ICCC 2015)

作者： Kai Zhang Changchuan Yin Jin Xu Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications School of Information and Communication Engineering Beijing University of Posts and Telecommunications

Traditional handover algorithms are based on received signal strength indicator(RSSI) and traffic load intensity in orthogonal frequency division multiple access(OFDMA) systems, in order to guarantee all UEs' Quality of Service(QoS) and handover success ratio, a transceiver is activated even if there is only one low date rate activated user in its coverage area. In this paper, we propose an energy efficient handover algorithm combined coordinated multiplepoints(CoMP) with OFDMA in a cellular systems, energy efficiency is introduced into the handover algorithm as an important parameter. The idea of the design is to enable adjacent cells to shutdown partial transceivers in some timeslots in low traffic conditions by concentrating the activated edge UEs to less cells. All activated UEs are classified into edge users and center users according to their distance to base stations, the analysis indicates that there exist an optimal edge distance corresponding to the maximum energy efficiency under different load for the proposed algorithm. Furthermore, a practical and low-complexity scheme that only considers the edge users is put forward. The edge users are identified by the reference signal received power(RSRP). Simulation results show that it can obtain up to 60% energy reduction at low traffic scenario.

关键词： handover OFDMA systems energy efficiency

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Traffic and User Behavior Analysis of Online Mobile Games

Traffic and User Behavior Analysis of Online Mobile Games

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International Conference on Intelligent Human-Machine systems and Cybernetics, IHMSC

作者： Yuesen Xiong Jun Liu Zhenming Lei Luyin Chen Beijing Key Laboratory of Network System Architecture Convergence Beijing University of Posts and Telecommunications Beijing China HAOHAN Data Technology Co. LTD

ISBN: (纸本)9781479986477

Understanding user behavior of online mobile game user is quite important for online mobile game operators to improve user experience and increase revenue. In this paper, we present an approach to extract information of online mobile games from traffic records on network side and analyze user behavior based on the extracted information. Different from previous work, we use distributed computing platform including the Hadoop Distributed File system (HDFS) and the parallel processing software framework MapReduce. What's more, we analyze user behavior from four aspects: (i) activeness, (ii) diurnal variation, (iii) account distribution and (iv) version distribution. The analysis result based on the real data shows us some interesting conclusion that cann't be found before.

关键词： Games Land mobile radio Servers Internet Indexes Mobile computing

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Understanding How Users Change their Mobile Phones by Massive Data Analysis

Understanding How Users Change their Mobile Phones by Massiv...

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International Conference on Intelligent Human-Machine systems and Cybernetics, IHMSC

作者： Jun Liu Zhenming Lei Luyin Chen You Zhou Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China HAOHAN Data Technology Co. LTD

ISBN: (纸本)9781479986477

In the current highly competitive mobile phone market, understanding how users change their mobile phones is important for mobile network operators and phone manufactures, which is the focus of our study. In this paper, we analyze the user behavior of phone replacement from the perspective of users' economic conditions. We investigate and compare the migration of three major smartphone operating systems: iOS, Android and Windows Phone. In addition, we evaluate the customer loyalty of each operating system using the analytic hierarchy process (AHP) approach. This study is conducted based on the traffic data collected from a major cellular operator's network covering more than ten million users. The results demonstrate the relationships between users' phone replacement and economic conditions as well as the distinctions of customer loyalty among different operating systems.

关键词： Operating systems Economics Smart phones Mobile communication Monitoring Switches

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Research on WiFi User Dwell Time Distribution

Research on WiFi User Dwell Time Distribution

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Symposia and Workshops on Ubiquitous, Autonomic and Trusted Computing, UIC-ATC

作者： Jie Meng Yihong Hu Guochu Shou Zhigang Guo Junfei Huang Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Teleconnnunications Beijing China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Teleconnnunications Beijing China

ISBN: (纸本)9781467372121

In order to study the distribution law of human mobility time attribute and identify the individual identity according to the law, six months real data is collected in different scenarios through the Wireless-Data-Collection-Analysis-system developed by our laboratory. On the basis of AIC, we analyze the time distribution from the perspectives of wireless hotspot group users and individual users respectively. From the perspective of the group users, we verify that the users' daily cumulative dwell time meets the power-law distribution model. According to each user's average daily dwell time, we analyze the probability distribution of the average daily dwell time and conclude that it is consistent with the power-law with exponential cut off. From the angle of an individual user, we analyze the distribution of its daily dwell time in different time sections. The result shows that the daily dwell time probability distribution of the users who work on time is consistent with the multi-peak Gaussian distribution, and the moment of the highest peak point of different individuals are close. However, the distribution of the daily dwell time for those who do not need to work on time is related to the average daily dwell time. The shorter the average daily dwell time is, the better the distribution is in line with the long-tailed distribution.

关键词： Mobile communication Mathematical model Wireless communication Exponential distribution IEEE 802.11 Standard Mobile handsets Data models

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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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