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Error exponents for two-hop Gaussian multiple source-destination relay channels

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science China(Information sciences) 2012年第2期55卷 348-359页

作者： DENG PanLiang1,3.LIU YuanAn1,3.XIE Gang2.3.WANG XiaoYu1,3.TANG BiHua1,3.& SUN JianFeng1,3.1school of Electronic Engineering,beijing {2. of {3. and telecommunications,beijing 100876,China 2.0} of Information and Communication Engineering,beijing {2. of {3. and telecommunications,beijing 100876,China 3.ey Laboratory of Universal Wireless Communication,Ministry of Education,beijing 100876,China 1. school of Electronic Engineering Beijing University of Posts and Telecommunications Beijing 100876 China3. Key Laboratory of Universal Wireless Communication Ministry of Education Beijing 100876 China2. School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

We investigate the two-hop multiple source-destination relay channels using the rate splitting trans-mission scheme where each source can split its message into private and public *** determine the system error probability via integrated exponent function under amplify-and-forward(AF)and decode-and-forward(DF)relay *** most significant difference between AF and DF system error probability evaluations lies in a minimized cut-set bound of transmission rate under the DF *** are many cases among transmission rate intervals for different system parameters(*** power)and it is extremely complex to derive the system error probability for the DF *** obtain a relatively simple result,which unifies various cases by a few *** results show that the system error probability decreases with the increase of the public ***,in order to draw deep insight into the reliability requirement of each source node in this network,we provide the error exponent region(EER)for different source nodes to show the trade-off of error probability among source nodes.

关键词： error exponent error exponent region rate splitting multiple source-destination relay channel

A class of discounted models for singular diffusion control

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Chinese science Bulletin 2000年第5期45卷 405-408页

作者： LIU Kunhui, QIN Mingda & LU Chuanlai1. College of sciences, Northern Jiaotong university, {2. 100044, China 2. Department of Mathematics and Mechanics, {2. university of science and Technology, {2. 100083..China 3. Department of Information Engineering, beijing university of posts and telecommunications, beijing 100876, China Correspondence should be addressed to Lu Chuanlai College of sciences Northern Jiaotong University Beijing China Department of Mathematics and Mechanics Beijing University of Science and Technology Beijing China Department of Information Engineering Beijing University of Posts and Telecommunications Beijing China

A kind of discounted problems for singular diffusion control have been studied. The drift and diffusion coefficients of state process are nonlinear. The class of models has been basically extended from a corresponding one established by Karatzes et al. before. By applying some analysis methods different from earlier works, the sufficient and necessary conditions of the existence of optimal control have been obtained. If an optimal control exists, it is a 'transient reflection' of state process for two lines.

关键词： stochastic control variational equation singular stochastic control.

Location based spectrum sensing performance analysis over fading channels in cognitive radio networks

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The Journal of China Universities of posts and telecommunications 2010年第5期17卷 26-31页

作者： YAO Hai-peng,ZHOU Zheng,SUN Xuan,LI Bin school of Information and Communication Engineering,beijing {2. of {3. and telecommunications,beijing 100876,China [a] school of Information Communication Engineering Beijing University of Posts telecommunications Beijing 100876 China

This paper analyzes the spectrum sensing performance over fading channel,in which a licensee and multiple unlicensed users coexist and operate in the licensed channel in a local *** overall average probabilities of detection and false alarm by jointly taking the fading and the locations of all secondary users into account are derived,and a statistical model of cumulate interference is *** on the cumulate interference,a closed-form expression of outage probability at the primary user’s receiver according to a specific distribution of the fading is ***,the sensing parameters so as to minimize the total spectrum sensing error and maximize the average opportunistic throughput are *** is noted that the overall average performance analysis and results here enable to benchmark the design of specific spectrum sensing algorithms.

关键词： spectrum sensing cognitive radio cumulate interference outage probability

Search recommendation model based on user search behavior and gradual forgetting collaborative filtering strategy

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The Journal of China Universities of posts and telecommunications 2010年第3期17卷 110-117页

作者： LIU Chuan-chang State Key Laboratory of Networking and Switching Technology, beijing university of posts and telecommunications, beijing 100876, China [a] State Key Laboratory of Networking Switching Technology Beijing University of Posts telecommunications Beijing 100876 China

The existing search engines are lack of the consideration of personalization and display the same search results for different users despite their differences in interesting and purpose. By analyzing user＇s dynamic search behavior, the paper introduces a new method of using a keyword query graph to express user＇s dynamic search behavior, and uses Bayesian network to construct the prior probability of keyword selection and the migration probability between keywords for each user. To reflect the dynamic changes of the user＇s preference, the paper introduces non-lineal gradual forgetting collaborative filtering strategy into the personalized search recommendation model. By calculating the similarity between each two users, the model can do the recommendation based on neighbors and be used to construct the personalized search engine.

关键词： search recommendation model search behavior expression keyword query graph gradual forgetting collaborative filtering

Construction of nonbinary quantum cyclic codes by using graph method

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science in China(Series F) 2005年第6期48卷 693-702页

作者： LIU Tailin1,2.3. WEN Qiaoyan1 & LIU Zihui4 1. school of science,{2.,{3., China 2. State Key Laboratory of Integrated Services Network, Xidian university, Xi’an 710071,China 3. Shandong Finance Institute, Jinan 2.0014, China 4. school of Mathematical sciences, Peking university, beijing 100871, China 1. school of science Beijing University of Posts and Telecommunications 100876 Beijing China 2. State Key Laboratory of Integrated Services Network Xidian University 710071 Xi’an China 3. Shandong Finance Institute 250014 Jinan China 4. school of Mathematical sciences Peking University 100871 Beijing China

Using the graph method proposed by Schlingemann and Werner, this paper introduces a technique to construct nonbinary quantum cyclic codes and provides a specific example. We also construct the quantum codes [[8, 2. 4]... 详细信息

关键词： nonbinary quantum stabilizer codes quantum cyclic codes

Fault management:analysis of fault location algorithm in optical network

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The Journal of China Universities of posts and telecommunications 2009年第4期16卷 23-28,97页

作者： ZHENG Yan-lei ,HUANG Shan-guo,ZHANG Xian,GU Wan-yi school of Telecommunication Engineering,beijing {2. of {3. and telecommunications,beijing 100876,China [a]school of Telecommunication Engineering beijing university of {2. and {3. beijing 100876 China

This article proposes a new fault location mechanism in optical network. In this mechanism, a network alarm packet format with time-stamp is introduced to implement fast restoration. In locating the fault, the existing schemes are usually complex and inaccessible when solving the multifailure location problem. For multifailures, the proposed mechanism using time-stamps is more efficient in locating the fault and decreasing computational complexity.

关键词： fault location alarming packet time-stamp optical network

Direct-sequence codes based blind synchronization algorithm for UWB systems

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The Journal of China Universities of posts and telecommunications 2009年第3期16卷 45-51页

作者： QIAO Yong-wei,L Tie-jun,REN Zhi-yuan school of Information Engineering,beijing {2. of {3. and telecommunications,beijing 100876,China [a]school of Information Engineering beijing university of {2. and {3. beijing 100876 China

A new blind （non-data-aided） synchronization algorithm based on direct-sequence （DS） codes is proposed for ultra-wideband （UWB） systems. The proposed approach fully exploits prior knowledge of DS codes and bypasses channel estimation. The real-time acquisition is achieved using integrating-and-dumping （I＆D） operation and DS codes matching filter. Because of pseudo randomicity and periodicity of DS codes, both the speed and the accuracy of synchronization are improved significantly. A lower bound on the acquisition probability of the proposed approach is also derived. Simulations confirm performance improvement of the proposed algorithm relative to existing alternatives in terms of acquisition probability, normalized mean square error （NMSE）, and bit error rate （BER）.

关键词： UWB systems synchronization DS codes

AODV routing overhead analysis based on link failure probability in MANET

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The Journal of China Universities of posts and telecommunications 2010年第5期17卷 109-115页

作者： ZHANG Qin-juan,WU Mu-qing,ZHEN Yan,SHANG Cui-li school of Telecommunication Engineering,beijing {2. of {3. and telecommunications,beijing 100876,China [a] school of Telecommunication Engineering Beijing University of Posts telecommunications Beijing 100876 China

This article puts forward an Ad-hoc on-demand distance vector routing （AODV） routing overhead analysis method in mobile Ad-hoc network （MANET）.Although multiple routing protocols have been proposed to improve the performance,scarcely any paper analyzed the routing overhead caused by routing setup and maintenance processes in mathematical *** overhead consumes part of network resources and limits the supported traffic in the *** on-demand routing protocols like AODV,the routing overhead depends on the link failure probability to a great *** article analyzes the collision probability caused by hidden-node problem and the impact on link failure *** chain and rectangle scenarios,it presents a mathematical analysis of the theoretical routing overhead of AODV protocol based on link failure *** on OPNET 14.5 platform match well with the theoretical derivation which confirms the effectiveness of the analysis method.

关键词： MANET saturate throughput AODV routing overhead

User-perceived e-mail service QoS parameters and measurement

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The Journal of China Universities of posts and telecommunications 2010年第3期17卷 85-90页

作者： LI Yong-zhi , LIU Feng, LEI Zhen-ming, CHEN Ling school of Information and Communication Engineering, beijing university of posts and telecommunications,{2., China [a] school of Information Communication Engineering Beijing University of Posts telecommunications Beijing 100876 China

A group of quality of service （QoS） parameters of electronic mail （e-mail） traffic are proposed from users＇ perspective. These parameters cover three fields： delay, throughput and usability. Concept and algorithm of each parameter are presented and its effect on user perceptions is described. In order to evaluate the effectiveness of these parameters, an active measurement system is implemented. Measured results show that the group of QoS parameters we proposed can be used to get a comprehensive view of user-perceived e-mail service QoS.

关键词： user perceptions e-mail service QoS active measurement