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International Symposium on Wireless Communication systems (ISWCS)

作者： Tao Lei Xiangming Wen Zhaoming Lu Wenpeng Jing Biao Zhang Gang Cao Beijing Laboratory of Advanced Information Networks Beijing Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing Beijing Advanced Innovation Center for Future Internet Technology

This paper proposes a frame loss rate (FLR) and received signal strength indicator (RSSI) prediction based handoff management scheme to reduce the ping-pong effect caused by the purely RSSI based handoff decision schemes in IEEE 802.11 networks. The proposed scheme is performed by each mobile station (MS) in a decentralized manner. In the proposed scheme, the FLR information is used as handoff trigger criterion. To perceive the change trends of wireless link thus reducing the target AP selection time, the proposed scheme adopts polynomial regression-based RSSI prediction approach. The predicted RSSI together with FLR information is used for target access point (AP) selection. Moreover, we construct neighboring AP information list (NAIL) for MSs to store the above information. Therefore, the proposed scheme can also be called NAIL-based handoff management scheme. The results indicate that the proposed scheme can effectively reduce the invalid handoffs and avoid the ping-pong effect.

关键词： Wireless communication Nails Ad hoc networks Monitoring IEEE 802.11 Standard Received signal strength indicator Wireless LAN

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A modified Matérn hard core point process for modeling and analysis of dense IEEE 802.11 networks

A modified Matérn hard core point process for modeling and ...

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International Symposium on Wireless Communication systems (ISWCS)

作者： Tao Lei Xiangming Wen Zhaoming Lu Wenpeng Jing Kun Chen Xiaoguang Zhao Beijing Laboratory of Advanced Information Networks Beijing Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing Beijing Advanced Innovation Center for Future Internet Technology

ISBN: (纸本)9781509020621

Stochastic geometry is a powerful tool for modeling wireless networks employing various MAC protocols with random topologies. For wireless networks operating carrier sense multiple access/collision avoidance (CSMA/CA) protocol, there are distance constraints between simultaneous transmitters, and only one node is allowed to transmit within its carrier sensing range. Matérn hard core point process is generally used to model and analyze the performance of this type of networks, because it is a repulsive point process that also defines a minimum distance between any two points. However, the traditional Matérn HCPP has the defect of underestimating the intensity of concurrent transmission nodes, which will affect the accuracy of analysis results, when wireless nodes are densely deployed. In this paper, we propose a modified Matérn HCPP called TM-HCPP which can mitigate the intensity underestimation problem to model dense IEEE 802.11 networks. Then, we simulate the network coverage probability using the traditional Matérn HCPP and the proposed TM-HCPP, and compare the simulated results with the theoretical analyzed results. Simulation results validate the accuracy of the proposed TM-HCPP.

关键词： IEEE 802.11 Standard Interference Measurement Wireless networks Fading channels Geometry Protocols

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The Application of Regex in Advertisements Filtration and Performance Analysis

The Application of Regex in Advertisements Filtration and Pe...

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

作者： Jianshan Li Dazhong He Fang Liu Huan Wang Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China HAOHAN Data Technology Co. LTD. Beijing China

ISBN: (纸本)9781509007691

Regular expression has developed a lot since it was invented in 1950s. There are many application scenarios fitting to use regular expression, like string search, string match and so on. The reason why it is so popular is that regular expression has a powerful processing capability to deal with undecided format string. When it comes to advertisements filtration, the regular expression can work well due to the undecided format of URL (Uniform Resource Locator). In this paper, we study the fundamental algorithms of regex engine, then applicate regular expressions in advertisements filtration. In order to get a higher matching rate, we need to feed the regular match engine with a certain number of expressions. In this paper, we will study the performance of different regular matching libraries used in the scenery of advertisements filtration. This will be a basis to choose a proper regex library for other similar sceneries.

关键词： Uniform resource locators Filtration Engines Libraries Google Impedance matching Internet

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Sampling Method in Traffic Logs Analyzing

Sampling Method in Traffic Logs Analyzing

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

作者： Hu Zhang Jun Liu Wenli Zhou Shuo Zhang Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China HAOHAN Data Technology Co. LTD. Beijing China

ISBN: (纸本)9781509007691

In this paper, we aim to quantify the amount of degradation and bias that sampling introduces with respect to the non-sampled traffic data taking into account different sampling rates, different sampling policies, different sampling population, and different analysis tasks. First, we analyze the impact of sampling on summation task. Second, we apply sampling method to aggregation by a particular dimension task. We find that the relative error of different keys in aggregation are very different which will greatly limit the effect of sampling method on data compression when the application has strict limit to maximum relative error. So we implement a novel reservoir sampling policy based on our application and furthermore optimize it by combine static sampling policy with reservoir sampling policy. The results demonstrate that the proposed method can effectively control the maximum relative error while maintain data compression rate comparable to existing static sampling methods. Finally we analyze the user loss rate as a function of sampling step under system sampling policy. Through deeply inspect the number of logs for each user, we find the reason why large user loss rate occurs. Our results can provide useful reference for quick approximate analysis using sampling method in traffic logs analyzing area.

关键词： Sampling methods Sociology IP networks Reservoirs Telecommunication traffic Degradation

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A Reliable MAC Protocol for Hybrid Wireless Sensor networks

A Reliable MAC Protocol for Hybrid Wireless Sensor Networks

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IEEE International Conference on Internet of Things

作者： Sijun Dou Danpu Liu Beijing Laboratory of Advanced Information Network Beijing University of Posts and Telecommunications P.R. China Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications P.R. China

ISBN: (纸本)9781509058815

The lifetime of Energy-harvesting Wireless Sensor networks (EH-WSNs) is ideally infinite. However, these networks are costly to implement, and unreliable due to unstable ambient energy. Consequently, Hybrid Wireless Sensor networks (HWSNs) consisting of Energy-harvesting Sensor Nodes (EHSNs) and Battery-powered Sensor Nodes (BPSNs) gain the spotlight Nevertheless, HWSNs confront the volatility of BPSNs that result in the unreliability of the whole network. In order to solve this issue, we design a reliable Hybrid MAC (H-MAC) protocol targeting HWSNs. The proposed protocol consists of two important mechanisms, i.e. Hybrid Polling and Hybrid Duty-cycle Scheduling. The former emphasizes on setting different polling transmission probabilities for BPSNs and EHSNs, while the latter on configuring different duty cycles. Both mechanisms are designed to suppress the energy dissipation of BPSNs by effectively utilizing the renewable energy of EHSNs, so that the stability of network can be guaranteed within its lifetime. Simulation results demonstrate that the average lifetime of BPSNs is significantly increased compared to the baseline protocols. Furthermore, the network transmission performance is also promoted.

关键词： EH-WSNs HWSNs EHSNs

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A fair listen-before-talk mechanism for LTE-U using a coalition formation approach

A fair listen-before-talk mechanism for LTE-U using a coalit...

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International Symposium on Wireless Communication systems (ISWCS)

作者： Wuqiong Ding Xiangming Wen Zhaoming Lu Wenpeng Jing Yan Zeng Beijing Key Laboratory of Network System Architecture and Convergence Beijing Advanced Innovation Center for Future Internet Technology Beijing Laboratory of Advanced Information Networks Beijing Beijing University of Posts and Telecommunications Beijing China

LTE on unlicensed bands (LTE-U), which is a promising way to meet the increasing mobile data demand, has attracted world-wide interests. However, the fair coexistence of LTE-U and WLAN is a critical issue to be solved. In this paper, we devise a semi-distributed channel access approach for LTE-U in dense deployed scenario to improve its capacity and achieve fair coexistence with WLAN. Specifically, the basic listen-before-talk (LBT) mechanism is employed to guarantee the fairness for WLAN, which is similar with the medium control access (MAC) protocol of WLAN. However, in order to decrease the high collision probability at heavy traffic load, a coalition strategy is introduced, in which the LTE-U base stations (BSs) would form into groups, and each group would contend for accessing the channel as one entity. This will effectively reduce the number of stations contending for accessing the channel and the collision probability as a result. In particular, in order to obtain the coalition solution, the cooperative game theory is introduced, and a low-complexity coalition formation algorithm is proposed based on the concept of recursive core in cooperative game. Simulation results verify the effectiveness of the proposed channel access approach, especially improving the LTE-U capacity and ensuring the fairness between LTE-U and WLAN.

关键词： Wireless LAN Games Interference IEEE 802.11 Standard Throughput Signal to noise ratio Mobile communication

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An improved dbf processor with a large receiving antenna for echoes separation in spaceborne SAR

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Progress In Electromagnetics Research C 2016年 67卷 49-57页

作者： Mo, Hongbo Xu, Wei Zeng, Zhimin School of Information and Communication Engineering Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing100876 China Spaceborne Microwave Remote Sensing System Department Institute of Electronics Chinese Academy of Sciences Beijing100190 China

Digital beamforming (DBF) on receive in elevation with a large receiving antenna will be widely adopted in future spaceborne synthetic aperture radar (SAR) missions to improve system performances. Furthermore, DBF can be used to separate echoes corresponding to different sub-pulses in some novel spaceborne SAR imaging modes. This paper proposes an improved DBF processor with a large receiving antenna for separating echoes. The proposed DBF processor includes three important parts: multiples sharp receiving beam generation, range compression and null steering. Compared with the conventional DBF processor in spaceborne SAR, the proposed DBF processor can separate echoes with better performances. Simulation results on point targets demonstrate validity of the proposed DBF processor. © 2016, Electromagnetics Academy. All rights reserved.

关键词： Receiving antennas

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Software Defined Multi-OLT Passive Optical network For Flexible Traffic Allocation

Software Defined Multi-OLT Passive Optical Network For Flexi...

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International Symposium on Optoelectronic Technology and Application 2016(OTA 2016)——Conf.15 Optical Communication and Optical network

作者： SHIZONG Zhang RENTAO Gu YUEFENG Ji JIAWEI Zhang HUI Li Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication EngineeringBeijing University of Posts and Telecommunications State Key Lab of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications

With the rapid growth of 4G mobile network and vehicular network services,mobile terminal users have increasing demand on data sharing among different radio remote units(RRUs) and roadside units(RSUs)

ISBN: (纸本)9781510607743

关键词： Passive optical network Software defined networking Bandwidth optimization Passive optical networks access network wavelengths Traffic core network control surfaces Building construction architecture bandwidth on demand Bandwidth

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A 3-D Polarization Quadrature Amplitude Modulation Method and Constellation Mapping

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China Communications 2015年第10期12卷 16-26页

作者： SUN Xuehong ZHANG Haiying ZENG Zhimin GUO Caili Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication EngineeringBeijing University of Posts and Telecommunications Key Laboratory of Intelligent Sensing for Desert Information School of Physics Electrical EngineeringNingxia University

As a new three-dimensional(3-D)modulation,Polarization Quadrature Amplitude Modulation(PQAM) can be regarded as the combination of Pulse amplitude modulation(PAM) and Quadrature Amplitude Modulation(QAM) *** can better improve the digital communication efficiency and reduce the Symbol error rate(SER) of the system than one-dimensional or two-dimensional modulation *** to design a feasible constellation is the most concerned problem of PQAM *** paper first studies the relationship between the SER theoretical value of PQAM and the distribution of M and N,proposes a new M,N allocation ***,a new and straightforward design method of constructing higher-level 3-D signal constellations,which can be matched with the PQAM,and the constellation can divided into three different structures according to the ary for ***,the simulation results show that:in PQAM system,the modulation scheme and the constellation mapping scheme are proposed in this paper which can effectively reduce the system SER and improve the anti-noise performance of the system.

关键词： polarization quadrature amplitude modulation minimum euclidean distance symbol error probability 3-D constellation

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QoS-priority based load balancing algorithm for LTE systems with mixed users

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The Journal of China Universities of Posts and Telecommunications 2015年第3期22卷 9-17页

作者： Chuai Gang Meng Fanfan Sun Li School of Information and Communication Engineering Beijing University of Posts and Telecommunications Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and Telecommunications Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications

Focusing on the load balancing problem among multi-cells in long term evolution （LTE） networks with mixed users, a new multi-objective optimization modeling strategy, which integrates the guaranteed bit rate （GBR） and the best effort （BE） users, was proposed. In consideration of quality of service （QoS） priorities of different users, a decomposition method was presented to solve the original model. Derivations such as applying Lagrange multiplier method, sub-optimal solutions for mixed users were deduced. Based on derived solutions, including resource allocation schemes, a practical multi-objective load balancing algorithm jointly dealing with mixed users was given. Simulation shows a significant improvement of GBR users＇ satisfaction level and BE users＇ throughput in LTE networks by using the proposed algorithm.

关键词： long term evolution system quality of service mixed users multi-objective optimization load balancing resource allocation

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