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International Conference on network Computing and Information Security (NCIS)

作者： Zhang Jian Zhu Qi Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and Telecommunications Nanjing China

Cognitive radio(CR) is a concept to improve the utilization of scarce spectrum resources in wireless communication, and orthogonal frequency division multiplexing (OFDM) is regarded as the best technology to match with the CR systems. In this paper, a new adaptive resource allocation algorithm for OFDM CR systems is presented. This algorithm solves the optimization problem based on maximize the total transmit bit rates of secondary users, on the one hand, the total transmit power of secondary users should below the transmit power constraint, on the other hand, the interference to primary users should under the maximum interference level, then allocate sub channels by an improved Hungarian Algorithm, and load bits and power by greedy algorithm. Simulation results show that the proposed algorithm can improve the system throughput comparing with some other sub optimal algorithms.

关键词： Interference Resource management OFDM Cognitive radio Optimization Barium

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Secret and reliable coding mechanism for noncoherent multisource network coding

Secret and reliable coding mechanism for noncoherent multiso...

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IEEE International Conference on communication Software and networks

作者： Chen, Siguang Wu, Meng Lu, Weifeng Jin, Yi College of Computer Science Nanjing University of Posts and Telecommunications Nanjing China College of Telecommunications and Information Engineering Nanjing Univ. of Posts and Telecommunications Nanjing China Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education China College of Informatics and Electronics Zhejiang Sci-Tech University Hangzhou China

ISBN: (纸本)9781612844855

This work considers the communication scenario where multiple sources transmit information to one or more receivers and these receivers request the information from all the sources. We construct a secret and reliable coding mechanism for noncoherent multisource network coding by extending the work [9, 10] to multisource case. Although the network scenario suffers from an adversary that can re-select the tapping links in different time slot and inject z erroneous packets into network, and the transmission links suffer from a packet erasures, our scheme can retrieve the original information secretly and accurately from the corrupt and deficient information. Meanwhile, the secret and reliable multisource network coding scheme can obtain an asymptotic achievable rate of k2z3. © 2011 IEEE.

关键词： network coding

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The bit error rate performance of MPSK over extended Rayleigh fading channel

The bit error rate performance of MPSK over extended Rayleig...

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IET International communication Conference on wireless Mobile and Computing, CCWMC 2011

作者： Li, Yingchun Tang, Sixuan Ge, Xiaoguang School of Communication and Information Engineering Key Lab of Specialty Fiber Optics and Optical Access Net Works Shanghai University Shanghai 200072 China Key Laboratory of Wireless Sensor Network and Communication Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences 865 Changning Road Shanghai 200050 China

ISBN: (纸本)9781849195058

In this paper, the symbol error rate performances of MPSK over extended slow Rayleigh fading channel are studied. Closed expression for MPSK signalling over non-frequency slow fading channels is derived. Since the classical Rayleigh fading channel is a special case of the extended Rayleigh fading channel where the inphase and quadrature components of the corresponding complex-valued Gaussian noise process are statistically independent, the derived expression can be verified by comparison with the results for the classical Rayleigh fading channel. The presented results are useful in studying the performance of digital modulation signals transmission over mobile fading channels.

关键词： Bit error rate

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The Failover Performance of Multimedia Transporting by SCTP

The Failover Performance of Multimedia Transporting by SCTP

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International Conference on wireless communications, networking and Mobile Computing (WiCom)

作者： Wen-Nai Wang Mei Peng Fang-Fang Tang Jing-Ling Zhu Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing University of Posts and Telecommunications Nanjing China Key Lab of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications) Ministry of Education Nanjing China School of Comm. and Inform. Engg. Nanjing Univ. Posts and Telecomm. China

The Stream Control Transmission Protocol (SCTP) which provides multihoming at transport layer has been extended recently for multimedia streaming and vertical handover. However, failure recover control is still in design to meet real-time multimedia services. In this paper, we investigate experimentally the performance of SCTP's failover and fail-recover relying on an open source platform. The result shows that in stream transporting by lksctp module, the failover completed time distributes within 63 to 70 seconds, and the fail-recover with 0 to 25 seconds. It is also found that fail-recover time is strongly correlated with SCTP Heartbeat events.

关键词： Multimedia communication Streaming media Servers Switches Real time systems Protocols Heart beat

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Spectrum sensing for cognitive OFDM system using free probability theory

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Journal of Information and Computational Science 2011年第10期8卷 1847-1859页

作者： Wang, Lei Zheng, Baoyu Cui, Jingwu Meng, Qingmin Institute of Signal Processing and Transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China Key Lab. of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Ministry of Education China

Free probability theory as a main branch of random matrix theory is a valuable tool for describing the asymptotic behavior of multiple systems, especially for those with large random matrices. In this paper, by using free probability theory, a new spectrum sensing scheme for cognitive OFDM system is proposed, which shows how asymptotic free behavior of random matrices and the property of Wishart distribution can be used to assist spectrum sensing for cognitive radios in such scenario. Simulation results show that the proposed scheme has a better detection performance than the energy detection technique and the maximum-minimum eigenvalue scheme even for the case of a small sample of observations. © 2011 by Binary Information Press.

关键词： Cognitive radio

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A New Resource Allocation Algorithm in OFDM System

A New Resource Allocation Algorithm in OFDM System

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2011 International Conference on Computer Science and Information technology(ICCSIT 2011)

作者： Liu Xiaolan Yang Longxiang Liu Xu Jiangsu Key Lab of Wireless Communications Nanjing University of Posts and Telecommunications Key Lab of Broadband Wireless Communications and Sensor Network Technology (Nanjing University of Posts and Telecommunications) Ministry of EducationChina

ISBN: (纸本)9781612848334

In this paper, we present an improved power allocation algorithm that maximizes the total capacity in the OFDM system. The improved allocation algorithm is based on the existing water-filling algorithm. To reduce the computational complexity in calculating water-filling level and make up for the shortcomings of the equally distributed algorithm, we propose the improved allocation algorithm where some subcarriers adopt water-filling algorithm and others take equally distributed algorithm. Besides, we will introduce two parameters M and V in the equally distributed algorithm to increase the system performance. Simulation has been done to prove that our algorithm has the performance better to the existing water-filling algorithm and has the lower computational complexity than it. Our algorithm also can be used in actual systems.

关键词： OFDM power allocation water-filling algorithm equally distributed algorithm

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Wavelet-analysis based file-sharing P2P traffic prediction algorithm

International Journal of Digital Content Technology and its ...

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International Journal of Digital Content technology and its Applications 2011年第6期5卷 46-54页

作者： Wu, Min Wang, Ruchuan Han, Zhijie College of Computer Nanjing University of Posts and Telecommunications Nanjing Jiangsu 210003 China Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Nanjing Jiangsu 210003 China Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Ministry of Education Jiangsu Province Nanjing Jiangsu 210003 China

The increasing P2P network traffic on the Internet has leaded to the problem of network congestion. In the consequence of the diversification of the P2P business and protocol, research on the management of P2P traffic has many problems to resolve. Prediction of the P2P traffic is the kernel problem in the P2P traffic management. Based on the existed P2P traffic characters, this paper structures a P2P traffic model, gives a traffic prediction algorithm bases on wavelet-analysis, and proves the accuracy of the algorithm. Simulation experiment figures that the algorithm has a high prediction precision and a superior real-time performance.

关键词： Wavelet analysis

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TWO-WAY DENOISE-AND-FORWARD network CODING OPPORTUNISTIC RELAYING AIMING AT MINIMIZING EUCLIDEAN DISTANCE IN MULTI-ACCESS PHASE

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Journal of Electronics(China) 2011年第4期28卷 433-443页

作者： Jia Xiangdong Yang Longxiang Shao Shixiang Wireless Communications Key Lab of Jiangsu Province Nanjing University of Posts and Telecommunications Nanjing 210003 China Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing University of Posts and Telecommunications Nanjing 210003 China College of Mathematics and Information Science Northwest Normal University Lanzhou 730070 China

To exploit the effect of modulation schemes on the best relay selection,a novel Jointing Modulation schemes max-min criterion(JM-max-min) is proposed firstly for Two-Way De-Noise-and-Forward(DNF) Opportunistic Relaying systems(TW-DNF-OR) by aiming at minimizing the Pairwise Error Probability(PEP) of Multi-Access(MA) phase which dominates the error per-formance of TW-DNF-OR due to the presence of MA *** proposed JM-max-min criterion integrates perfectly the minimum distances of constellations and the relay links ***,with the proposed JM-max-min criterion,we analyze the Symbol Error Probabilities(SEPs) of MA phase and BroadCast(BC) phase by using the approximated mathematics analysis,and present the corresponding closed-form expressions to *** numerical analysis shows,for a given modulations combination at both sources,the TW-DNF-OR systems with the proposed JM-max-min criterion outperform the one with the conventional max-min criterion.

关键词： Cooperative communications Opportunistic relaying network coding Max-min crite-rion

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COOPERATIVE WIDEBAND SPECTRUM SENSING BASED ON SEQUENTIAL COMPRESSED SENSING

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Journal of Electronics(China) 2011年第3期28卷 313-319页

作者： Gu Bin Yang Zhen Hu Haifeng Institute of Signal Processing and Transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing University of Posts and Telecommunications Nanjing 210003 China

Compressed sensing offers a new wideband spectrum sensing scheme in Cognitive Radio (CR). A major challenge of this scheme is how to determinate the required measurements while the signal sparsity is not known a priori. This paper presents a cooperative sensing scheme based on se-quential compressed sensing where sequential measurements are collected from the analog-to-information converters. A novel cooperative compressed sensing recovery algorithm named Simul-taneous Sparsity Adaptive Matching Pursuit (SSAMP) is utilized for sequential compressed sensing in order to estimate the reconstruction errors and determinate the minimal number of required meas-urements. Once the fusion center obtains enough measurements, the reconstruction spectrum sparse vectors are then used to make a decision on spectrum occupancy. Simulations corroborate the effec-tiveness of the estimation and sensing performance of our cooperative scheme. Meanwhile, the per-formance of SSAMP and Simultaneous Orthogonal Matching Pursuit (SOMP) is evaluated by Mean-Square estimation Errors (MSE) and sensing time.

关键词： Cognitive Radio (CR) Wideband spectrum sensing Sequential compressed sensing Matching pursuit

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Image-based position estimation and adaptive modulation coding in vehicular communication

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Journal of networks 2011年第12期6卷 1754-1759页

作者： Yang, Hao Meng, Qingmin Gu, Xiong Zheng, Baoyu School of Geography and Biological Information Key Lab of Broadband Wireless Communication and Sensor Network Tech. Ministry of Education Nanjing University of Posts and Telecommunications Nanjing 210003 China National Mobile Communications Research Lab Southeast University Nanjing 210096 China

Vehicle position estimation is a key technology for Inter-Vehicle communications, while template matching can be used to get information of vehicular position. In the paper, a simplified template matching, namely area-based template match is considered. A vehicular communication system designed for wireless data application is proposed where a camera is fixed in a vehicle which is served as a base station. By means of comparison between the outline area of vehicular image and reference templates, the base station can obtain the position estimation of the vehicle. The reference templates can be pre-calculated from a group of field experiment data. Based on supervised learning, we develop an image-based vehicle position estimation method and evaluate its effect on an adaptive coding modulation scheme. The computer simulation results show that in the wireless fading channel with the OFDM physical model, compared with fixed modulation coding scheme, the studied adaptive modulation and coding (AMC) scheme taking account of the position estimation can gain greater throughput. © 2011 ACADEMY PUBLISHER.

关键词： Orthogonal frequency division multiplexing

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