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Cooperative HARQ protocol and diversity analysis of systems with multiple incremental relays

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The Journal of China Universities of posts and telecommunications 2009年第5期16卷 8-13页

作者： FAN Bin , WANG Wen-bo, LIN Yi-cheng, ZHENG Kan Wireless Signal Processing and Network Lab, Key Laboratory of Universal Wireless Communication, Ministry of Education, beijing university of posts and telecommunications, beijing 100876, China [a]Wireless Signal Processing and Network Lab Key Laboratory of Universal Wireless Communication Ministry of Education beijing university of posts and telecommunications beijing 100876 China

Wireless networks contain an inherent distributed spatial diversity that can be exploited by relays. Relay networks can take advantage of the broadcast-oriented nature of wireless transmission, but require more radio resource to transmit data for their multi-hop traits. Fortunately, incremental relaying technique, which can choose direct or multi-hop transmission adaptively, can efficiently utilize resource. In this article, the incremental transmission with amplify-and-forward （AF） relays is focused on. A practical hybrid-automatic retransmission request （HARQ） protocol is designed, and the related optimal relay selection strategy is proposed. To analyze the cooperative diversity of system with the proposed protocol, the capacity lower bound is deduced. Simulation and analytical results indicate that by adopting the optimal relay selection strategy, the system with the proposed HARQ protocol can achieve an order of cooperative diversity that equals the aggregated number of the relay and source nodes.

关键词： cooperative HARQ AF incremental relay diversity gain

VCO clock synchronization loop combined with dispersion equalization in optical coherent receivers

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The Journal of China Universities of posts and telecommunications 2010年第5期17卷 122-128页

作者： FAN Yang-yang,CHEN Xue,ZHOU Xian,ZHOU Wei-qin,ZHU Hai,LI Zhi-yu Key Laboratory of Information Photonics and Optical Communications,Ministry of Education,beijing university of posts and telecommunications,beijing 100876,China [a] Key Laboratory of Information Photonics Optical Communications Ministry of Education Beijing University of Posts telecommunications Beijing 100876 China

In optical coherent receivers,the timing error detector （TED） in synchronization loop can not work normally when signal is distorted by large *** paper proposes a novel clock synchronization scheme which adds a butterfly-structured adaptive equalizer to the loop to fulfill synchronizations,equalizations and polarization de-multiplexing of two polarization states simultaneously under the control of single voltage-controlled oscillator （VCO）.Simulink simulation demonstrates the rationality and the feasibility of the combined loop with single VCO.

关键词： optical coherent receiver synchronization dispersion equalization

Pruning Redundant Alarm Correlation Patterns

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The Journal of China Universities of posts and telecommunications 2002年第2期9卷 45-48页

作者： CHEN Yue, LIN Qi ning, TU Zhi yun (Business Management school, beijing university of posts and telecommunications, beijing 100876, P.R.China) Business Management school Beijing University of Posts and Telecommunications Beijing 100876 P.R.China

Efficient methods exist for discovering association rules fromlarge collections of data. The number of discovered rules can,however, be so large. At the same time it is well known that manydiscovered associations are redundant or minor variations of *** existence may simply be due to chance rather than truecorrelation. Thus, those spurious and insignificant rules should beremoved. In this paper, we propose a novel technique to over- Comethis problem. The technique firstly introduces the newconcept-structure rule cover, and then present a Quantitative methodto prune redundant correlation patterns. The user can now obtain acomplete picture of the do- Main without being overwhelmed by a hugenumber of rules.

关键词： alarm correlation structural rule cover correlation logic minimumsupport

Identifying online traffic based on property of TCP flow

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The Journal of China Universities of posts and telecommunications 2009年第3期16卷 84-88页

作者： HONG Min-huo,GU Ren-tao,WANG Hong-xiang,SUN Yong-mei,JI Yue-feng Key Laboratory of Optical Communications and Lightwave Technologies,beijing university of posts and telecommunications,beijing 100876,China [a]Key Laboratory of Optical Communications and Lightwave Technologies beijing university of posts and telecommunications beijing 100876 China

Classification of network traffic using port-based or payload-based analysis is becoming increasingly difficult when many applications use dynamic port numbers, masquerading techniques, and encryption to avoid detection. In this article, an approach is presented for online traffic classification relying on the observation of the first n packets of a transmission control protocol （TCP） connection. Its key idea is to utilize the properties of the observed first ten packets of a TCP connection and Bayesian network method to build a classifier. This classifier can classify TCP flows dynamically as packets pass through it by deciding whether a TCP flow belongs to a given application. The experimental results show that the proposed approach performs well in online Internet traffic classification and that it is superior to naive Bayesian method.

关键词： network traffic classification inter-arrival time TCP flow Bayesian network

A Distributed Intranet/Web Solution to Integrated Management of Access Networks

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The Journal of China Universities of posts and telecommunications 2002年第1期9卷 35-39页

作者： LIU Ting, SHOU Guo chu, GUO Zhi gang (Continuing Education school, beijing university of posts and telecommunications, beijing 100876, P.R. China) Continuing Education school Beijing University of Posts and Telecommunications Beijing 100876 P.R. China

In this article, we describe the present situation of accessnetwork management, enumerate a few prob- lems during the developmentof network management systems, then put forward a distributedIntranet/Web solution named iMAN to the integrated management ofaccess networks, present its architecture and protocol stack, and de-scribe its application in practice.

关键词： Intranet/Web access network network management iMAN

Combining Digital Watermarks with Two-Color Bitmap Image

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The Journal of China Universities of posts and telecommunications 2000年第Z1期 31-35页

作者： SAAD A Amer, YANG Yi-xian (Information Security Center, beijing university of posts and telecommunications, beijing 100876, P.R. China)

A technology for combining digital watermarks with two-color bitmap image based on the threshold watermarking method is presented. Our technology doesn’t add any thing to the digital media, but combines the watermarks in two-color bitmap image by looking for some characteristic values in the bitmap and uses the relationship between the watermarks and the characteristic values to prove the copyright protection. The choice of the characteristic values depends on the choice of a cryptographic key known by the owner of the bitmap. The benefit of using a cryptographic key is to combine the watermarks with the bitmap in a high secure way.

关键词： digital watermarks information hiding copyright protection

A New Analytical Model for TCP Reno with Bursts Error Considered

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The Journal of China Universities of posts and telecommunications 2003年第4期10卷 17-22页

作者： DENG Jian-min,JI Hong,YUE Guang-xin,YIN Chang-chuan(school of Telecommunication Engineering, beijing university of posts and telecommunications, beijing 100876,P.R. China) school of Telecommunication Engineering Beijing University of Posts and Telecommunications 北京 100876

In this paper, we present a new analytical model for TCP Reno, and thismethod can also be used in other versions of TCP. The first order two-state Markovian model is usedto describe the wireless link, so as to deal with the burst error in wireless links very well. Thetimeout mechanism of TCP is also considered and a geometric method describes the exponential growthof TCP timeout. Also this method is effective for the study of the growth of TCP transmissionwindow. Analytical results indicate that this model is effective.

关键词： TCP reno markovian model renewal theory throughput

Novel resource allocation algorithms for multiuser downlink MIMO-OFDMA of FuTURE B3G systems

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Progress in Natural science:Materials International 2009年第9期19卷 1141-1146页

作者： Qiaoyun Sun, Hui Tian *, Shuang Wang, Kun Dong, Ping Zhang Key Laboratory of Universal Wireless Communication, Ministry of Education, Wireless Technology Innovation Institute, beijing university of posts & telecommunications, {4., China [a]Key Laboratory of Universal Wireless Communication Ministry of Education Wireless Technology Innovation Institute Beijing University of Posts & Telecommunications Beijing 100876 China

In this paper, subcarrier and power allocation problems for multiuser downlink MIMO-OFDMA of the FuTURE B3G TDD system are investigated. For the reciprocity of the TDD channel, the channel state information can be employed at the transmitter, thus eigen beamforming can be implemented efficiently. With the goal of minimizing the total transmit power under the condition that the QoS requirement of each user can be guaranteed, a novel dynamic resource allocation scheme is proposed to exploit the multiuser diversity gain. The proposed algorithm involves adaptive subcarrier allocation, adaptive modulation and eigen beamforming and achieves significant improvement in overall system performance. Based on the proposed scheme, a modified bit and power allocation is developed. The modified scheme reduces the computational complexity at little expense of system performance. Numerical simulations show that the proposed algorithm and the modified scheme can decrease the total transmit power effectively.

关键词： Adaptive modulation and coding Dynamic resource allocation Eigen beamforming MIMO–OFDMA

The band structures of BSb and B_xGa_(1-x)Sb alloys

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science China(Physics,Mechanics & Astronomy) 2009年第6期52卷 843-847页

作者： XIONG DePing1, ZHOU ShouLi2, WANG Qi3, LUO Li1, HUANG YongQing3 & REN XiaoMin3 1 school of Physics and Optoelectronic Engineering, Guangdong university of Technology, Guangzhou 510006, China 2 College of Information Engineering, Zhejiang university of Technology, Hangzhou 310032, China 3 Key Laboratory of Optical Communication and Lightwave Technologies Ministry of Education, beijing university of posts and telecommunications, {4., China 1. school of Physics and Optoelectronic Engineering Guangdong University of Technology Guangzhou 510006 China 2. College of Information Engineering Zhejiang University of Technology Hangzhou 310032 China 3. Key Laboratory of Optical Communication and Lightwave Technologies Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

The band structures of BSb and BxGa1-xSb alloys are studied using first-principles calculations in the generalized gradient approximation. By SQS-8 supercells to model a random alloy, the direct transition energy-gap (Γ15v- Γ1c) bowing of 3.0 eV is obtained for BxGa1-xSb alloys in x = 0-50%, in x = 0-11% the energy-gap is the band-gap and increases by 7 meV/%B with boron composition increasing; by SQS-16 supercells the bowing parameter is about 1.9 eV in x = 0-12.5%. The formation enthalpies of mixing, ΔH, are calculated for BxGa1-xAs and BxGa1-xSb alloys. A comparison of enthalpies indicates that BxGa1-xSb films with boron composition of 7% may be possible.

关键词： band-gap bowing parameter boride alloys