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2016 International Conference on Applied Mechanics, Mechanical and Materials Engineering(AMMME 2016)

作者： Yan ZHEN Hai-jun WANG Qing-hai OU Ling-kang ZENG Jia-yong FENG State Grid Information & Telecommunication Co. Ltd.the Future of Science and Technology City National Grid Park Changping District Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications

In this paper, we provide a cost optimized algorithm to design a real-time data transmission network architecture and realize real-time monitoring of transmission line in smart grid. How to deliver this real-time data to the control center efficiently is a critical challenge to build an intelligent smart grid. We formulate a three-layer network structure that can provide cost effective data transmission by the meantime, the bandwidth, delay, and connectivity constraints can be well met. Furthermore, the optimal placement of the LTE transceivers is studied aiming at maximizing the bandwidth and minimizing the delay in information delivery. The results we present in the paper individually analyze the effect of variation in each of the constraint on the cost of the network while other constraints are assumed to take up average values. Our analysis shows that three-layer wireless network used in smart grids can solve the problem of real-time data transmission and reduce the overall cost of transmission line monitoring network by the algorithm proposed in this paper.

关键词： Smart grid Transmission line monitoring network design Optimal deployment algorithm

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Sparse Multi-User Detection for Non-Orthogonal Multiple Access in 5G systems

Sparse Multi-User Detection for Non-Orthogonal Multiple Acce...

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IEEE Annual International Symposium on Personal, Indoor, and Mobile Radio Communications

作者： Kesen He Yangqing Li Changchuan Yin Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781509032556

A key technology in the 5th generation (5G) wireless communications is non-orthogonal multiple access (NOMA) which can effectively support massive random access. Since in a 5G system the number of active users generally does not exceed 10% of the total number of users in practice, the main challenge for multi-user detection (MUD) is the joint detection of sparse active users and their data. To address this challenge, we propose a novel compressed sensing based NOMA (CS-NOMA) scheme which can be deployed in a CDMA or an OFDM system and does not have control signaling overhead and need no knowledge of the active state of users. In the proposed scheme, K users are multiplexed over N shared resources (K >> N). Then, a CS-based MUD is applied to the proposed CS-NOMA scheme. Simulation results show that, in the case that active users are sparse (e.g., 10%), the proposed scheme can achieve a superior performance even when the system loading is up to 300%.

关键词： Non-orthogonal multiple access Compressed sensing Sparse multi-user detection

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Channel transition monitoring based spectrum sensing in mobile cognitive radio networks 1

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10th International Conference on Cognitive Radio Oriented Wireless networks, CROWNCOM 2015

作者： Duan, Meimei Zeng, Zhimin Guo, Caili Liu, Fangfang Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing100876 China

ISBN: (数字)9783319245409

ISBN: (纸本)9783319245393

Spectrum sensing is a key technique for providing an opportunistic spectrum band in cognitive radio networks. The opportunistic spectrum is determined by the channel state. Mobility makes the problem of the traditional sensing mechanism more severe than in static scenarios. In this paper the channel transition monitoring based spectrum sensing mechanism is proposed. The proposed scheme not only reduces the influence of mobility on the current sensing mechanism, but also ensures reliability of the sensing and improves the spectrum efficiency. Our simulation results show that the proposed mechanism outperforms the traditional mechanism. Our method supplements the traditional sensing mechanism and enhances the efficiency of cognitive radio networks. © Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2015.

关键词： Cognitive radio

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Performance Analysis of Delayed Mobile Data Offloading With Multi-level Priority

Performance Analysis of Delayed Mobile Data Offloading With ...

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IEEE Annual International Symposium on Personal, Indoor, and Mobile Radio Communications

作者： Heng Xu Xiangming Wen Zhaoming Lu Zhiqun Hu Wenpeng Jing Kun Chen Beijing Laboratory of Advanced Information Networks Beijing Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing

ISBN: (纸本)9781509032556

WiFi offloading is a cost-effective and practical solution to alleviate the problem of highly congested cellular networks. Recent theoretical and experimental studies show that delayed WiFi offloading where traffic can be delayed to increase the chance of meeting WiFi can significantly improve offloading efficiency. Nevertheless, there is no exact analytic model to analyze the offloading benefits with different types of traffic. In this paper, we propose a preemptive priority queuing analytic model for delayed offloading with multi-level priority traffic and derive expressions for the average delay and offloading efficiency of traffic with different priorities as a function of the WiFi availability, deadlines, and other key parameters. At last, we validate the accuracy of our queuing model by simulation in different scenarios and clarify how to choose a suitable deadline for traffic of different priorities.

关键词： IEEE 802.11 Standard Analytical models Queueing analysis Mobile computing Cellular networks Data models

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Discretization of an square electromagneic cloak based on transformation optics 6

Discretization of an square electromagneic cloak based on tr...

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6th IEEE International Symposium on Microwave, Antenna, Propagation, and EMC Technologies, MAPE 2015

作者： Li, Deng Hong, Weijun Li, Shufang Zhu, Jianfeng Biao, Peng Feng, Botao Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China Department of Electronics Engineering Shenzhen University Shenzhen China

ISBN: (纸本)9781467374415

Existing discrete electromagnetic cloaks are often limited to circular shape and always based on one dimensional discretization of radius variable in cylindrical coordinates. In this paper, we proposed a two dimensional (2D) discrete square invisible cloak which really does not require any continuous constitutive material parameters. The discrete square cloak consists of several homogeneous blocks, and they are discretized from the original transform medium whose material parameters are often continuous spatial functions of both x and y variables in Cartesian coordinates. With proper design of numbers of blocks, we demonstrated the scattering properties of the proposed cloaking structure through rigorous analysis of the scattered electromagnetic fields. The proposed cloaking structure could be possibly realized, therefore may lead to a practical path to an experimental demonstration of electromagnetic cloaking. © 2015 IEEE.

关键词： Electromagnetic fields

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MAP Estimation of the Ricean K Factor

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Canadian Journal of Electrical and Computer Engineering 2015年第2期38卷 130-131页

作者： Beaulieu, Norman C. Chen, Yunfei School of Information and Communication Engineering Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing100876 China School of Engineering University of Warwick CoventryCV47AL United Kingdom

An estimator for the Ricean K factor is designed by approximating the maximum a posterior (MAP) probability. The performance of the approximate MAP estimator is examined. Numerical results show that the approximate MAP estimator outperforms the approximate maximum likelihood estimator. It also outperforms the best moment-based estimator at small sample sizes. © 2015 IEEE.

关键词： Maximum likelihood estimation

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Global and individual mobility pattern discovery based on hotspots

Global and individual mobility pattern discovery based on ho...

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IEEE International Conference on Communications, ICC 2015

作者： Yang, Jie Zhang, Xinyu Qiao, Yuanyuan Fadlullah, Zubair Kato, Nei Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China Graduate School of Information Sciences Tohoku University Sendai Japan

ISBN: (纸本)9781467364324

Data collected from the mobile Internet have the potential knowledge to provide important human mobility patterns. Understanding human mobility patterns is important to many location-based services, and could be used to predict users' behavior. In this paper, we concentrate on the issue of discovering human mobility patterns on both global and individual levels based on hotspots. We study the human mobility trajectories during 22 days for 3474 individuals collected at the core of a metropolitan Long Term Evolution (LTE) network in China. We employ a parameter-free method to detect hotspots, and demonstrate the effectiveness of our mobility pattern discovery algorithm by using the hotspots identified on both global and individual levels. We analyze the occurrence time distribution of these patterns and find that the global mobility patterns have higher occurrence probability in the morning, which indicates that people in a city tend to share the common commuting routes. For individual mobility patterns, there exists a strong spatiotemporal correlation property, implying that the individual mobility patterns have their own typical occurrence time depending on the pattern's context. © 2015 IEEE.

关键词： Hotspot LTE networks Mobility characteristic Mobility pattern discovery

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Energy efficient handover algorithm in OFDMA systems

Energy efficient handover algorithm in OFDMA systems

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IEEE International Conference on Computer and Communications, ICCC 2015

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

ISBN: (纸本)9781467381253

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 multiple-points (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. © 2015 IEEE.

关键词： Energy efficiency

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A printed dual-wideband magneto-electric dipole antenna and its MIMO system for WLAN and WiMAX applications

A printed dual-wideband magneto-electric dipole antenna and ...

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IEEE International Conference on Computational Electromagnetics (ICCEM)

作者： Botao Feng Jianfeng Zhu Li Deng Wenxing An Qingsheng Zeng College of Electronic Science and Technology Shenzhen University Shenzhen China Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China Department of Electronic Engineering Tsinghua University Beijing China School of EECS University of Ottawa Ontario Canada

A novel three-dimensional printed dual-wideband complementary antenna with a dual-layer bow-tie dipole structure is proposed for WLAN/WiMAX applications. By using dual-η-shaped feeding structure to feed the dual-layer U-shaped bow-tie dipole, dual-wideband and complementary characteristics can be obtained. In addition, its MIMO system with a defected ground which can obviously improve the diversity performance is also designed. The antenna element can offer an impedance bandwidth of 8.1% (2.38 GHz-2.58 GHz) with a stable gain of 4.3±0.5 dBi, and an impedance bandwidth of 60.3% (3.20 GHz- 5.96 GHz) with a gain of 7.5±1.7 dBi for the lower and upper bands, respectively. By tuning parameters further, its MIMO system can provide an impedance bandwidth of 97.9% (2.05 GHz-5.98 GHz). Therefore, it can be potentially suitable for WLAN/WiMAX and MIMO unidirectional communications.

关键词： WiMAX Patch antennas Dipole antennas Connectors Oils Irrigation

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Based QoE-perceptive network selection of video applications in WLAN

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Journal of Information and Computational Science 2015年第13期12卷 5109-5117页

作者： Zhang, Hongchun Lu, Zhaoming Hu, Zhiqun Wen, Xiangming Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

Wireless Local Area networks (WLAN) is becoming increasingly important. But it is difficult for users to select the best target network for connection in WLAN. For multimedia applications, Quality of Experience (QoE) is an essential measurement for network evaluation, and particularly video applications need the guarantee of QoE. However, many proposed schemes do not take QoE into account. Therefore, a novel network selection mechanism for video applications that takes QoE into consideration is proposed. Users detect the states of the channel and the resource utilization and calculate the Peak Signal to Noise Ratio (PSNR), then use the mapping model to obtain QoE. This mechanism uses QoE in candidate networks as an indicator to select the best target Access Point (AP) network. The simulation results illustrate that QoE of video applications satisfies users' requirement, and the network throughput is greatly improved. ©, 2015, Journal of Information and Computational Science. All right reserved.

关键词： Signal to noise ratio

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