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IEEE Conference on Vehicular Technology (VTC)

作者： Zhengfu Li Zhaoming Lu Xiangming Wen Wenpeng Jing Zhicai Zhang Fengchao Fu Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing

The explosive growth of mobile multimedia services has caused tremendous network traffic in wireless networks and a great part of the multimedia services are delay-sensitive. Therefore, it is important to design efficient radio resource allocation algorithms to increase network capacity and guarantee the delay QoS. In this paper, we study the power control problem in the downlink of two-tier femtocell networks with the consideration of the delay QoS provisioning. Specifically, we introduce the effective capacity (EC) as the network performance measure instead of the Shannon capacity to provide the statistical delay QoS provisioning. Then, the optimization problem is modeled as a non- cooperative game and the existence of Nash Equilibriums (NE) is investigated. However, in order to enhance the self-organization capacity of femtocells, based on non-cooperative game, we employ a Q-learning framework in which all of the femtocell base stations (FBSs) are considered as agents to achieve power allocation. Then a distributed Q-learning-based power control algorithm is proposed to make femtocell users (FUs) gain maximum EC. Numerical results show that the proposed algorithm can not only maintain the delay requirements of the delay-sensitive services, but also has a good convergence performance.

关键词： Delays Interference Quality of service Power control Femtocell networks Macrocell networks Resource management

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Wideband spectrum sensing based on coprime sampling

Wideband spectrum sensing based on coprime sampling

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International Conference on Telecommunications (ICT)

作者： Shiyu Ren Zhimin Zeng Caili Guo Xuekang Sun Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing

In wideband compressive spectrum sensing, when the number of occupied subbands in the monitored wideband increases, the existing compressive sensing approaches have to raise the sampling rate to maintain a desired sensing performance. What is worse, that will add computational complexity of the following signal reconstruction. To overcome this issue, this paper proposes a novel wideband spectrum sensing approach based on time-domain coprime sampling. Our approach first estimates the power spectrum of the wideband signal by employing the coprime sampling scheme, then performs detection via a subband-bin energy detector. The cornerstone of our approach is that we can generate a Nyquist space sampled autocorrelation from the sub-Nyquist samples by implementing the coprime sampling scheme. Demonstrated by the simulations, our proposed wideband sensing approach has a better performance under high compression ratio and a better robustness against noise compared with the orthogonal matching pursuit (OMP). Also it is illustrated that our approach has the advantage over computational complexity by analyzing. Considering the merits synthetically, the novel wideband sensing approach adapts better to a higher bandwidth by comparision.

关键词： Sensors Correlation Wideband Computational complexity Noise Estimation Time-domain analysis

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Temperature stability of magnetic field for periodic permanent-magnet focusing system

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Rare Metals 2014年第2期33卷 180-184页

作者： Li Li Jian-Ya Chen Yun-Jie Liu Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications

In this study, finite element analysis based on an Ansoft Maxwell software was used to reveal the temperature stability of a magnet ring and the equivalent structural periodic permanent-magnet（PPM） focusing system. It is found that with the temperature increasing, the decrease rate of magnetic induction peak（Bz）maxof single magnet ring is greater than that of remanence Brof magnet in the range from room temperature to 200 °C, however,the PPM focusing system do have the same temperature characteristics of permanent-magnet materials. It indicates that the magnetic temperature properties of the PPM system can be effectively controlled by adjusting the temperature properties of the magnets. Moreover, the higher permeability of the magnets indicates the less Hcb, giving rise to lower magnetic induction peak （Bz）′max： Finally, it should be noted that the magnetic orientation deviation angle θ（／15°） of permanent magnets has little effect on the focusing magnetic field of the PPM system at different temperatures and the temperature stability. The obtained results are beneficial to the design and selection of permanent magnets for PPM focusing system.

关键词： Periodic permanent-magnets focusing system Rare earth permanent magnets Finite element simulation Temperature stability Wireless underground sensor network

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Multi-access selection with attractor selection algorithm in heterogeneous network

Multi-access selection with attractor selection algorithm in...

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IEEE International Conference on Communications in China (ICCC)

作者： Huan Wu Xiangming Wen Zhaoming Lu Qi Pan Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781509002443

To solve the problems of heterogeneous wireless network, such as scarce spectrum resources, interference among radio resources and blindness area caused by excessive demands of mobile users, a novel system which integrates the power line carrier (PLC) and the wireless network (WN) with the attractor selection algorithms is proposed. Due to multi-selected paths being transmitted information according to the network environment, the robustness and stability of the integrated the PLC and the WN (IPWN) are improved. Moreover, to transmit the data packets in the different communication protocol of PLC and WN, the effective virtual layer (EVL) above the network layer is employed to convert protocol between the PLC and the WN by resealing the packet. Then, the attractor selection algorithm is employed to select the optimal path among the PLC or the WN adaptively according to the external conditions. Simulation results demonstrate that, comparing to the PLC and the WN, the packet delay of the IPWN is smaller with the increase of the packets, and the IPWN has strong robustness and stability.

关键词： Wireless networks Heterogeneous networks Bandwidth Protocols Mathematical model Multimedia communication

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Polarization Based Spectrum Sensing for Cognitive Radios in Presence of Arrival Angle

Polarization Based Spectrum Sensing for Cognitive Radios in ...

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IEEE Conference on Vehicular Technology (VTC)

作者： Xiaoyu Yuan Caili Guo Shuo Chen Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781479980895

Due to the presence of arrival angle, which can reduce the received energy of primary signal and then degrade the performance of polarization detectors, we propose polarization information based spectrum sensing methods considering arrival angle in this paper. Using the generalized likelihood ratio test (GLRT) paradigm, we derive two algorithms with different statistical prior information and finally propose a blind Polarization and Arrival angle Eigenvalue Detection (PAED), which is the optimal polarization algorithm in the presence of arrival angle. Our results show that the proposed PAED method exhibits better performance than other existing techniques, particularly when the number of samples is small, which is critical in vehicular applications.

关键词： Detectors Maximum likelihood estimation Noise Covariance matrices Eigenvalues and eigenfunctions Cognitive radio

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A Real-Time network Traffic Anomaly Detection system Based on Storm

A Real-Time Network Traffic Anomaly Detection System Based o...

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

作者： Gang He Cheng Tan Dechen Yu Xiaochun Wu Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781479986477

In recent years, with more and more people shopping, chatting and video online, the Internet is playing a more and more important role in human's daily life. Since the Internet is so close to our lives, it contains so much personal information that will cause a lot of troubles or even losses when divulged. So it's necessary and urgent to find a efficient way to detect the abnormal network behavior. In this paper, we present a new detection method based on compound session. In contrast to previous methods, our approach is based on the cloud computing platform and the cluster system, using Hadoop Distributed File system (HDFS) to analysis and using Twitter Storm to make real-time network anomaly detection come true.

关键词： Real-time systems Storms Telecommunication traffic Fasteners Downlink Monitoring Uplink

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Analysis of network User Virtual Identity Based on Hadoop

Analysis of Network User Virtual Identity Based on Hadoop

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

作者： Gang He Wenlong Qiu Dechen Yu Xiaochun Wu Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781479986477

With the development of the Internet and the explosive growth of business data, there are massive network User Virtual Identities (NUVIs) on Internet when network user accessing different applications. Compared with previous methods, we will propose an algorithm to analyze which NUVIs belong to the same person. What's more, our approach is based on the cloud computing platform and the cluster system, including the Hadoop Distributed File system (HDFS) and the parallel processing software framework MapReduce.

关键词： Monitoring Cloud computing Computational modeling Programming Parallel processing Merging

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User association based on Cobb-Douglas function in HetNets with hybrid energy sources

User association based on Cobb-Douglas function in HetNets w...

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IEEE International Conference on Communications in China (ICCC)

作者： Hongzhang Xu Tiankui Zhang Zhimin Zeng Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

In the wireless cellular networks, energy harvesting is a promising green technology to utilize the renewable energy obtained from the environment. Terminals can utilize the renewable energy to save on-grid power and reduce carbon emissions. This paper investigates the user association problem in heterogeneous networks with hybrid energy sources, where all the BSs are powered by on-grid power and renewable energy. The Cobb-Douglas production function is first introduced to formulate a user association problem under a flow-level traffic model, where the weight can be changed to achieve different tradeoffs. Then a low complexity distributed algorithm implemented by user and base station side is proposed, which can converge to the global optimal solution. Simulation results demonstrate that the proposed algorithm can utilize the renewable energy efficiently, and enable flexible tradeoffs by adjusting the weight value.

关键词： Power demand Renewable energy sources Green products Production Wireless communication convergence Energy harvesting

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Compressed spectrum sensing based on correlation of spectrum occupation states between sensing periods

Compressed spectrum sensing based on correlation of spectrum...

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MILCOM, Military Communications Conference

作者： Yanbo Wang Caili Guo Xuekang Sun Chunyan Feng Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

In order to reduce sampling costs and computational complexity in the signal reconstruction process of existing compressed spectrum sensing (CSS), we propose a novel two-step compressed spectrum sensing (TS-CSS) scheme exploiting correlation of occupation states between sensing periods. At the first step of TS-CSS, we detect busy sub-channels of last sensing period to find the sub-channels that are still busy in current sensing period. In this way, part of supports of received signal is known and the remainder of the signal is a sparser signal than the original. Then the second step adjusts number of samples collected in the compressive sampling process according to number of unknown supports. By doing so, overall sampling rate and computational complexity are minimized. Compared with traditional one step compressed spectrum sensing (OS-CSS) scheme, our TS-CSS needs fewer samples and lower computations to yield an accurate sensing outcome. Valid simulation is conducted in the work.

关键词： Sensors Radio frequency Wideband Correlation Cascading style sheets Computational complexity Frequency response

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Enterprise network Status Analysis Using Hadoop and Lucene

Enterprise Network Status Analysis Using Hadoop and Lucene

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

作者： Gang He Yijian Xiao Decheng Yu Xiaochun Wu Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781479986477

The present work introduces an improved approach of analyzing and storing status data of enterprise network. Raw data collected was pre-processed with Hadoop, the famous open-source distribute computing framework. After the pre-process procedure, an open-source information retrieval software library, Lucene, is introduced to do the following data indexing and analyzing job in this research. With the help of these outstanding tools, we managed to find out some valuable status information using approaches proposed in this paper. It will do a great good to the administration and management of enterprise network.

关键词： Indexing Bandwidth Open source software Distributed databases Real-time systems Data analysis

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