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Asia-Pacific Conference on communications

作者： Da Wang Lin Bai Chen Chen Ye Jin Jinho Choi State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science Peking University Beijing China School of Electronic and Information Engineering Beihang University Beijing China School of Engineering Swansea University Swansea UK

ISBN: (纸本)9781467347266

Recently collaborative relay systems have been studied to increase the spectral efficiency and extend the range of wireless communications. In this paper, we consider the collaborative relay beamforming (CRBF) for multiuser systems. In the proposed method, we select base station (BS) antennas for each user and optimize their CRBF weights under two different types of power constraints, which are the total relay power constraint and individual relay power constraints, by exploiting the notion of the maximization of the worst-case received signal-to-interference-and-noise ratio (SINR). The optimization problem of the CRBF weights can be efficiently solved using a semidefinite relaxation (SDR) *** derive an iterative CRBF scheme to jointly select the BS antennas and optimize the CRBF weights to maximize the worst SINR among all users. Simulation results validate our theoretical analysis and demonstrate the tradeoffs between the number of BS antennas and the number of relays in the CRBF system.

关键词： Relays Signal to noise ratio Interference Antennas Vectors Array signal processing Collaboration

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Realistic simulation and experimental validation of adjacent-channel interference in planning of industrial wireless networks

Realistic simulation and experimental validation of adjacent...

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8th ACM Symposium on Performance Evaluation of Wireless Ad Hoc, Sensor, and Ubiquitous networks, PE-WASUN'11

作者： Chen, Feng Huegel, Bernd Dressler, Falko Industry Automation Division Siemens AG Germany Dept. of Computer Science University of Erlangen Computer Networks and Communication Systems Germany Institute of Computer Science University of Innsbruck Computer and Communication Systems Austria

ISBN: (纸本)9781450309004

Interference is among of the most critical issues in wireless communication, especially in industrial application fields. Even though interference is rather well understood today, there is a lack of validated simulation models integrated with common network simulators. We present an integrated simulation and planning toolkit that allows us to estimate adjacent channel interference among multiple wireless networks such as IEEE 802.11 WLANs. We performed an extensive set of lab experiments not only to validate the presented simulation model but also to come up with quick lookup tables to be used for industrial network planning. The developed simulation framework provides very accurate physical layer modeling that is of utmost importance for WiFi planning in automation facilities. Not limited to the IEEE 802.11 protocols, the proposed interference model can be easily adapted for coexistence planning of WLANs and the IEEE 802.15.4 based WPANs in the 2.4 GHz band. Copyright 2011 ACM.

关键词： Table lookup

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Power Allocation using Vickrey Auction and Sequential First-Price Auction Games for Physical Layer Security in Cognitive Relay networks

Power Allocation using Vickrey Auction and Sequential First-...

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IEEE International Conference on communications

作者： Tianyu Wang Lingyang Song Zhu Han Xiang Cheng Bingli Jiao The State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science Peking University Electrical and Computer Engineering Department University of Houston

ISBN: (纸本)9781457720529

We consider a cognitive radio network in which multiple pairs of secondary users (SUs) communicate by a one-way relay node over orthogonal channels with the existence of an eavesdropper close to the destination. The transmit power of the relay needs efficient distribution for maximizing the sum secrecy rate of the SU pairs, meanwhile satisfying the interference constraint at the single primary user (PU). Specifically, we introduce two multi-object auctions, i.e. the Vickrey auction and the sequential first-price auction, to perform this power allocation problem. We prove the existence and give the general form of the only equilibrium for each auction. We also propose two algorithms based on the equilibriums, respectively. From the simulation results, we see that the system secrecy rate curve of the Vickrey auction gradually coincides with that of the optimal allocation with increasing power units, while the sequential first-price auction reflects more fairness.

关键词： Relay networks power splitting Transmitter power Physical layer Interference constraints Privacy Sequential Cognitive radio optimal allocation Game theory relay

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Polypyrrole thin film sensor base surface plasmon resonance for detection of Cu(II) and Fe(III) in aqueous solution

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AIP Conference Proceedings 2012年第1期1482卷 200-204页

作者： Amir R. Sadrolhosseini A. S. M. Noor Mohd Maarof Moksin Mahnaz M. Abdi Hassan Soleimani Ahmad Fauzi Abas Zainal Abdin Talib Center of Excellence for Wireless and Photonics Networks (WiPNet) Faculty of Engineering Universiti Putra Malaysia 43400UPM Serdang Malaysia Department of Computer and Communication Systems Engineering Faculty of Engineering Universiti Putra Malaysia 43400UPM Serdang Malaysia Department of Physics Faculty of Science Universiti Putra Malaysia 43400UPM Serdang Malaysia Department of Chemistry Faculty of Science Universiti Putra Malaysia 43400 Serdang Selangor Malaysia and Institute of Tropical Forestry and Forest Products (INTROP) Universiti Putra Malaysia Malaysia Fundamental and Applied Science Department Universiti Technology PETRONAS 31750 Sri Iskandar Malaysia Center of Excellence for Wireless and Photonics Networks (WiPNet) Faculty of Engineering Universiti Putra Malaysia 43400UPM Serdang Malaysia and Department of Computer and Communication Systems E Malaysia

In this study, the performance of surface plasmon resonance method incorporated with polypyrrole sensing layer was examined for detection of Cu (II) and Fe (III) ions in aqueous solutions. The polypyrrole was prepared by electro-oxidation method on a gold layer for the detecting low concentration ions (0.1, 1 5 10 20 ppm). The experiments carried out at room temperature, and each sample was flowed through the flow cell. A photodiode registered the SPR signals as the function of rotation angle and thickness of layers. For observing the association and dissociation processes, the experiments repeated more than ten times, and the sensorgrams were obtained. Furthermore, Langmuir model was utilized to describe the binding interactions of ions with the polypyrrole layer. The lower concentration detection limit was about 0.1 ppm and the terminal resonance angles were occurred after the 300 s. The sensor was also found to be more sensitive to the presence of Cu than Fe ions.

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Compact triplexer in two-dimensional hexagonal lattice photonic crystals

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Chinese Optics Letters 2011年第4期9卷 87-90页

作者：任宏亮马建平温浩覃亚丽吴哲夫胡卫生姜淳金耀辉 College of Information Engineering Zhejiang University of Technology College of Computer Science and Technology Zhejiang University of Technology State Key Laboratory of Advanced Optical Communication Systems and Networks Shanghai Jiao Tong University

We design a compact triplexer based on two-dimensional （2D） hexagonal lattice photonic crystals （PCs）. A folded directional coupler （FDC） is introduced in the triplexer beside the point-defect micro-cavities and line-defect waveguides. Because of the reflection feedback of the FDC, high channel drop efficiency can be realized and a compact size with the order of micrometers can be maintained. The proposed device is analyzed using the plane wave expansion method, and its transmission characteristics are calculated using the finite-difference time-domain method. The footprint of the triplexer is about 12 9 μm, and its extinction ratios are less than -20 dB for 1310 nm, approximately -20 dB for 1490 nm, and under -40 dB for 1550 nm, making it a potentially essential device in future fiber-to-the-home networks.

关键词： Crystal lattices Defects Fiber optic networks Finite difference time domain method Multiplexing equipment Optical waveguides Personal communication systems Time domain analysis Two dimensional

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Flexible playout adaptation for low delay AAC RTP communication

Flexible playout adaptation for low delay AAC RTP communicat...

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2011 3rd International Conference on communication systems and networks, COMSNETS 2011

作者： Issing, Jochen Reuschly, Stefan Dressler, Falko Färbery, Nikolaus Dept. Computer Science 7 Computer Networks and Communication Systems Friedrich-Alexander-University Erlangen Germany Multimedia Transport Group Fraunhofer Institute for Integrated Circuits Erlangen Germany

ISBN: (纸本)9781424489534

We present an integrated approach for flexible playout adaptation for high quality audio transmission over impaired network connections. The key concept of our framework is a continuous measurement of the transmission delay, the delay variation, and packet loss. Based on these measurements, the adaptive playout control employs audio time stretching using audio concealment and frame dropping techniques to keep the low delay requirements. In the literature, playout adaptation techniques have mainly been considered for voice over IP, using silence periods between talkspurts, or for high quality audio transmission over dedicated network links. To the best of our knowledge, our playout algorithm is the first achieving low delay high quality audio streaming over impaired network connections for both music and speech. We used a significant number of network traces to estimate the variation of the network quality in DSL, WLAN, UMTS and GPRS links and to update the parameters of our playout adaptation technique. Experimental results clearly indicate that our system provides very high accuracy for the desired accepted late loss rate and achieves a fast playout adaptation, even for rapidly changing network conditions. © 2011 IEEE.

关键词： Audio acoustics

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A preliminary study on ancestral voting algorithm for availability improvement of mutual exclusion in partitioned distributed systems

A preliminary study on ancestral voting algorithm for availa...

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International Conference on computers and Computing, ICCC'11

作者： Zarafshan, Faraneh Karimi, Abbas Al-Haddad, S.A.R. Saripan, M. Iqbal Subramaniam, Shamala Department of Computer and Communication Systems Engineering Faculty of Engineering UPM Malaysia Department of Computer Engineering Faculty of Engineering IAU-Arak Branch Iran Department of Communication Technology and Networks Faculty of Computer Science and IT UPM Malaysia

ISBN: (纸本)9781618040008

Mutual exclusion as one of the main problems associated with distributed systems requires that at any time t, only one site can access the common copies of file f. As a result of node or link failures, distributed system may be partitioned into two or more groups of nodes which cannot communicate each other anymore;meanwhile they must be able to update their copies of file f consistently, in order to keep the system up. Voting algorithms are the main solutions presented to maintain mutual exclusion in case of distributed system partitioning. So far several techniques have been presented to increase the availability of mutual exclusion in partitioned distributed systems. In this paper a new dynamic voting approach called as ancestral voting is presented to increase the availability of distributed system. Our analyses show that this algorithm can maintain mutual exclusion and increase the availability of distributed system between 2.86% and 59.83% in comparison with previous algorithms. Furthermore, it is very simple and does not need many calculations.

关键词： Availability

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Energy-Efficient Radio Resource and Power Allocation for Device-to-Device communication Underlaying Cellular networks

Energy-Efficient Radio Resource and Power Allocation for Dev...

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International Conference on Wireless communications and Signal Processing

作者： Feiran Wang Chen Xu Lingyang Song Zhu Han Baoxian Zhang State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science Peking University Beijing China Electrical and Computer Engineering Department University of Houston Houston USA Graduate University of Chinese Academy of Sciences Beijing China

ISBN: (纸本)9781467358309

Device-to-device (D2D) communication underlaying cellular networks brings significant benefits to resource utilization, improving user's throughput and extending battery life of user equipments. However, the allocation of radio resources and power to D2D communication needs elaborate coordination, as D2D communication causes interference to cellular networks. In this paper, we propose a novel joint radio resource and power allocation scheme to improve the performance of the system in the uplink period. Energy efficiency is considered as our optimization objective since devices are handheld equipments with limited battery life. We formulate the the allocation problem as a reverse iterative combinatorial auction game. In the auction, radio resources occupied by cellular users are considered as bidders competing for D2D packages and their corresponding transmit power. We propose an algorithm to solve the allocation problem as an auction game. We also perform numerical simulations to prove the efficacy of the proposed algorithm.

关键词： Energy-Efficient Radio Resource

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Feedback compression for time-correlated MIMO block-fading channels using huffman coding

Feedback compression for time-correlated MIMO block-fading c...

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2011 IEEE 13th International Conference on communication Technology, ICCT 2011

作者： Xu, Chen Zhang, Leiming Song, Lingyang Zhao, Yuping Jiao, Bingli State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electrical Engineering and Computer Science Peking University Beijing 100871 China

ISBN: (纸本)9781612843070

In this paper, we investigate feedback compression for a general multiple-input multiple-output (MIMO) system over time-correlated Rayleigh block-fading channels. With a channel state transition graph characterized by Markov chain, we first compress channel state information (CSI) feedback through Huffman coding. We then propose a threshold based approach by neglecting the states with small transition probabilities with slight performance loss to further reduce the feedback rate. Finally, we study the relationship between the channel ergodic capacity and feedback rate with water-filling precoding. Analysis and simulation show that the feedback rate can be significantly reduced by the proposed algorithms. © 2011 IEEE.

关键词： MIMO systems

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The Investigation on the 1.53 μm Photoluminescence of Magnetron-Sputtered Er0.2Re1.8Si2O7 (Re=Yb, Y) Thin Films

The Investigation on the 1.53 μm Photoluminescence of Magne...

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Symposium on Photonics and Optoelectronics

作者： Wang, Bing Yuan, Ge Wang, Lei Guo, Ruimin Wang, Xingjun Zhou, Zhiping State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science Peking University Beijing 100871 China

The photoluminescence (PL) and decay time at 1.53μm of sputtered Er 0.2Re1.8Si2O7 (Re=Yb, Y) thin films were investigated. The enhancement of the PL at 974nm pumping in the Er 0.2Re1.8Si2O7 film was demonstrated comp... 详细信息

ISBN: (纸本)9781424465545

关键词： Photoluminescence

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