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EXIT analysis of M-algorithm based MIMO detectors and LDPC code design optimization

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science in China(Series F) 2009年第12期52卷 2248-2258页

作者： YOU MingHou1,2. TAO XiaoFeng1,2. CUI QiMei1,2.& ZHANG Ping1,2.1 Wireless Technology Innovation Institute, beijing university of posts and telecommunications, beijing 100876, China 2.Key Laboratory of Universal Wireless Communications, ({2. {3. of posts and telecommunications), Ministry of Education, beijing 100876, China Wireless Technology Innovation Institute Beijing University of Posts and Telecommunications Beijing 100876 China Key Laboratory of Universal Wireless Communications (Beijing University of Posts and Telecommunications) Ministry of Education Beijing 100876 China

This paper investigates joint design and optimization of both low density parity check （LDPC） codes and M-algorithm based detectors including iterative tree search （ITS） and soft-output M-algorithm （SOMA） in multiple-input multiple-output （MIMO） systems via the tool of extrinsic information transfer （EXIT） charts. First, we present EXIT analysis for ITS and SOMA. We indicate that the extrinsic information transfer curves of ITS obtained by Monte Carlo simulations based on output log-likelihood rations are not true EXIT curves, and the explanation for such a phenomenon is given, while for SOMA, the true EXIT curves can be computed, enabling the code design. Then, we propose a new design rule and method for LDPC code degree profile optimization in MIMO systems. The algorithm can make the EXIT curves of the inner decoder and outer decoder match each other properly, and can easily attain the desired code with the target rate. Also, it can transform the optimization problem into a linear one, which is computationally simple. The significance of the proposed optimization approach is validated by the simulation results that the optimized codes perform much better than standard non-optimized ones when used together with SOMA detector.

关键词： MIMO systems iterative receiver LDPC codes code optimization EXIT charts M-algorithm

Construction of LDPC codes over GF(q) with modified progressive edge growth

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The Journal of China Universities of posts and telecommunications 2009年第5期16卷 103-106,113页

作者： CHEN Xin , MEN Ai-dong, YANG Bo, QUAN Zi-yi school of Information and Communication Engineering, beijing university of posts and telecommunications,{2., China [a]school of Information and Communication Engineering beijing university of {2. and {3. beijing 100876 China

A parity check matrix construction method for constructing a low-density parity-check （LDPC） codes over GF（q）（q〉2. based on the modified progressive edge growth （PEG） algorithm is introduced. First, the nonzero locations of the parity check matrix are selected using the PEG algorithm. Then the nonzero elements are defined by avoiding the definition of subcode. A proof is given to show the good minimum distance property of constructed GF（q）-LDPC codes. Simulations are also presented to illustrate the good error performance of the designed codes.

关键词： LDPC codes over GF(q) progressive edge growth large minimum distance

Experimental investigation of MIMO relay channels statistics and capacity based on wideband outdoor measurements at 2.3. GHz

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science China(Information sciences) 2011年第9期54卷 1945-1956页

作者： NIE Xin 1,2.ZHANG JianHua 1,2.LIU ZeMin 1 & ZHANG Ping 1,2.1 Key Laboratory of Universal Wireless Communications,Ministry of Education {3. university of {2. and {3.,{3. 100876,China 2.Wireless Technology Innovation Institute,{3. university of {2. and {3.,{3. 100876,China 1. Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China2. Wireless Technology Innovation Institute Beijing University of Posts and Telecommunications Beijing 100876 China

Relay,which serves to enhance the performance of future communication networks,is one of the most promising techniques for IMT-Advanced *** potential performance improvement of relay is investigated in this *** investigation consists of two *** the first step,to obtain a better understanding of the fundamental properties of relay channels,we conducted outdoor measurements at 2.3. GHz with 50 MHz bandwidth in a typical urban area of *** links constituting the relay transmission,i.e.,the link between base station and relay station,the link between relay station and mobile station and the link between base station and mobile station were measured by employing a real-time channel *** main factors that affect the MIMO channel capacity,i.e.,the channel gain and effective degrees of freedom,are *** cross-polarization discrimination was obtained by utilizing space-alternating generalized expectation-maximization *** channel parameters of the three links are statistically analyzed and *** the second step,based on the measured data,the performance of different relaying schemes,i.e.,amplify-and-forward and decode-and-forward,is *** impact of RS antenna configuration on the capacity is also *** measurement and evaluation results reveal that the relay can significantly improve the system coverage and performance.

关键词： MIMO relay channels IMT-Advanced frequency band channel characteristics relay performance evaluation

Coexistence of broadband power line communication systems

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The Journal of China Universities of posts and telecommunications 2009年第4期16卷 125-128页

作者： YANG Biao ,L Ying-hua,ZHANG Hong-xin school of Electronic Engineering,beijing {2. of {3. and telecommunications,beijing 100876,China [a]school of Electronic Engineering beijing university of {2. and {3. beijing 100876 China

Recent progress in home networks enhances the application of broadband power line communication （BPL） since it does not require any installation of new communication lines or outlets. However, high-density distribution of BPL devices may bring down the access quality. Besides, the electromagnetic field radiating from the power line may cause interference with other radio systems. Thus, the objective of this study is to investigate the impact of cumulative interference in BPL systems, especially focused on indoor environment. A 2.D model describing the BPL transmission activity is proposed. Based on transmission characteristics of the main networks, it takes into account the coexistence effect of the BPL devices. The maximum acceptable density of BPL devices and the radiation field are finally determined.

关键词： BPL coexistence effect radiating electromagnetic field

Multiparty simultaneous quantum identity authentication with secret sharing

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science China(Physics,Mechanics & Astronomy) 2008年第3期51卷 321-327页

作者： YANG YuGuang1,2.WEN QiaoYan3.& ZHANG Xing4,5 1 College of Computer science and Technology,beijing {2. of Technology,beijing 10002.,China 2.State Key Laboratory of Information Security (Graduate {2. of the Chinese Academy of sciences),beijing 100049,China 3.school of science,beijing {2. of posts and {12.,beijing 100876,China 4 Institute of Electronic Technology,Information Engineering {2.,Zhengzhou 450004,China 5 Trusted Computing Laboratory,beijing {2. of Technology,beijing 10002.,China College of Computer science Technology Beijing University of Technology Beijing 100022 China State Key Laboratory of Information Security [Graduate university of the Chinese Academy of sciences] Beijing 100049 China school of science Beijing University of Posts telecommunications Beijing 100876 China Institute of Electronic Technology Information Engineering University Zhengzhou 450004 China Trusted Computing Laboratory Beijing University of Technology Beijing 100022 China

Two multiparty simultaneous quantum identity authentication (MSQIA) protocols based on secret sharing are presented. All the users can be authenticated by a trusted third party (TTP) simultaneously. In the first protocol,the TTP shares a random key K with all the users using quantum secret sharing. The ith share acts as the authentication key of the ith user. When it is necessary to perform MSQIA,the TTP generates a random number R secretly and sends a sequence of single photons encoded with K and R to all the users. According to his share,each user performs the corresponding unitary operations on the single photon sequence sequentially. At last,the TTP can judge whether the impersonator exists. The sec-ond protocol is a modified version with a circular structure. The two protocols can be efficiently used for MSQIA in a network. They are feasible with current technol-ogy.

关键词： quantum identity authentication secret sharing quantum cryptography

Valiant load-balancing and regionalized routing scheme

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The Journal of China Universities of posts and telecommunications 2010年第3期17卷 78-84页

作者： YANG Fan , WANG Zhen-kai, CHEN Jian-ya, LIU Yun-jie school of Information and Communication Engineering, beijing university of posts and telecommunications,{2., China [b] school of Information Communication Engineering Beijing University of Posts telecommunications Beijing 100876 China

Valiant load-balancing （VLB） routing scheme has drawbacks of logical full mesh, intermediate nodes （networks） and single application of topology. To address these, the authors propose a novel routing scheme called regionalized VLB （R-VLB）. Based on ideas of VLB and regionalizing, R-VLB divides the nodes of backbone network into several regions whose topological structure is logical full mesh, and combines shortest-path routing scheme and VLB routing scheme. R-VLB also achieves logical local interconnection, non-central nodes （networks） and a wide range of application of topology. The relevant theoretical analysis and simulation results show that R-VLB achieve good throughput and failure performance close to that of VLB, and it even has better delay performance. R-VLB provides an idea for the application of VLB routing scheme.

关键词： routing scheme VLB topology backbone network

Lifetime maximization of cooperative networks with mean channel gain information

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The Journal of China Universities of posts and telecommunications 2009年第4期16卷 98-103页

作者： YANG Chang-qing,WANG Wen-bo,ZHAO Shuang,PENG Mu-gen school of Information and Communication Engineering,beijing {2. of {3. and telecommunications,beijing 100876,China [a]school of Information and Communication Engineering beijing university of {2. and {3. beijing 100876 China

A simple but effective relay-selection and power-allocation scheme is proposed to maximize the lifetime of decode-and-forward （DF） cooperative networks under the constraint that only the mean channel gain information is available at the transmitters. The new scheme takes both channel state information （CSI） and residual energy information （REI） into consideration. To evaluate the performance of the proposed scheme, three typical relay-selection and power-allocation schemes, i.e., maximum residual energy （MRE）, minimum transmit power （MTP） and equal transmit power （ETP） are considered. Simulation results show that the proposed scheme outperforms the MRE and the MTP in lifetime duration and outage probability, while needing much less signal overhead compared with the ETP.

关键词： cooperative commtmication lifetime relay selection power allocation Rayleigh fading

Asymptotic performance of amplify-and-forward MIMO relaying with transmit antenna selection

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science China(Information sciences) 2010年第12期53卷 2631-2641页

作者： CAO Lei ,YANG DaCheng,YANG HongWen,FENG Chao & ZHANG Xin school of Information and Communication,beijing {2. of {3. and telecommunications,beijing 100876,China 1. school of Information and Communication Beijing University of Posts and Telecommunications Beijing 100876 China

This paper proposes two schemes,TAS-SD&RD and TAS-SR&RD,in which transmit antenna selection(TAS) strategies are combined with amplify-and-forward(AF) protocol in MIMO relaying scenario considering the destination has only limited channel state information(CSI) of the source-to-relay channel,and analyzes asymptotic performance of the two *** source,destination,and relay are equipped with multiple antennas,denoted by N S,N D,and N R,***,the paper derives the asymptotic outage probability and symbol error rate(SER) of the proposed schemes in the cooperative AF MIMO relaying *** analyses in high SNR regime lead to the conclusion that TAS-SD&RD and TAS-SR&RD can achieve full diversity order,N S N D + N R min{N S,N D },in some antenna configurations of the cooperative *** results that confirm our analyses are also presented in the paper.

关键词： cooperative amplify-and-forward(AF) multiple-input multiple-output(MIMO) relaying transmit antenna selection(TAS)

Research on user-aware QoS based Web services composition

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The Journal of China Universities of posts and telecommunications 2009年第5期16卷 125-130页

作者： LIU Feng , LEI Zhen-ming Key Laboratory of Information Processing and Intelligent Technology, beijing university of posts and telecommunications, beijing 100876, China [a]Key Laboratory of Information Processing and Intelligent Technology beijing university of {2. and {3. beijing 100876 China

To improve user experience of composite Web services, a user-aware quality of service （QoS） based Web services composition model is proposed. Under such model, a Web services selection method based on quantum genetic algorithm is proposed. This algorithm uses quantum bit encoding, dynamic step-length quantum gate angle adjustment, neighborhood service search and dynamic punishment strategy to expand search scope and speed up convergence. Simulation experiment shows that this algorithm is more efficient than other existing algorithms in Web services selection.

关键词： Web services composition user awareness quality of service quantum genetic algorithm