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Science china(information Sciences) 2011年第2期54卷 236-243页

作者： XU Kun, YIN Jie, NIU Jian, SUN XiaoQiang, WU Jian & LIN JinTong Key Laboratory of information Photonics and Optical communications, Ministry of Education, beijing university of {4. and Telecommunications, beijing 100876, china 1. Key Laboratory of information Photonics and Optical communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

We propose and experimentally demonstrate the heterodyne mixing and polarization diversity tech- niques in radio over fiber (ROF) systems with the advantages of high sensitivity and dispersion endurance. The generation of 2.5 Gb/s optical DPSK and PSK signals, fiber propagation and wireless transmission over 15 GHz subcarrier are illustrated with very low sensitivity of -26 and -32 dBm, respectively. Moreover, based on the wireless polarization diversity techniques, we successfully performed the transmission of 1.3 Gb/s uncompressed high definition television (HDTV) signals with high quality.

关键词： radio over fiber heterodyne mixing polarization diversity

Strain distribution and electronic structures of the InAs/GaAs quantum ring molecule in an applied electric field

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Science china(Physics,Mechanics & Astronomy) 2010年第9期53卷 1594-1599页

作者： JIA BoYong,YU ZhongYuan,LIU YuMin,YAO WenJie,YE Han & FENG Hao Key Laboratory of information Photonics and Optical communications(beijing university of {4. and Telecommunications),Ministry of Education,beijing 100876,china 1. Ministry of Education Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications) Beijing 100876 China

The strain distribution and electronic structures of the InAs/GaAs quantum ring molecule are calculated via the finite element *** our model,three identical InAs quantum rings are aligned vertically and embedded in the cubic GaAs *** the band edge modification induced by the strain,the electronic ground state and the dependence of ground state energy on geometric parameters of the quantum ring molecule are *** change of localization of the wavefunction resulting from the applied electric field along the growth direction is *** ground state energy decreases as the electric field intensity increases in a parabolic-like *** electric field changes the monotonic dependence of the energy level on the inter-ring distance into a non-monotonic ***,the electric field has no effect on the relationships between the energy level and other geometric parameters such as the inner radius and outer radius.

关键词： strain distribution electronic structure quantum ring molecule applied electric field

Cross layer scheduling for real-time traffic in multiuser MIMO-OFDMA systems

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The Journal of china Universities of posts and Telecommunications 2009年第3期16卷 24-29页

作者： SUN Qiao-yun,TIAN Hui,DONG Kun,ZHANG Ping Key Laboratory of Universal Wireless communications,Ministry of Education,beijing university of posts and Telecommunications,beijing 100876,china [a]Key Laboratory of Universal Wireless communications Ministry of Education beijing university of posts and Telecommunications beijing 100876 china

A novel cross layer scheduling algorithm is proposed for real-time （RT） traffic in multiuser downlink multiple-input multiple-output orthogonal frequency division multiple access （MIMO-OFDMA） wireless systems. The algorithm dynamically allocates resources in space, time and frequency domain based on channel state information （CSI）, users＇ quality of service （QoS） requirements and queue state information （QSI）. To provide higher data rate and spectrum efficiency, adaptive modulation and coding （AMC） is employed. The proposed algorithm can improve cell throughput and increase the number of users that can be supported while guaranteeing users＇ QoS requirements and fairness among all users. Simulation results indicate that the proposed algorithm can achieve superior performance.

关键词： MIMO-OFDMA cross layer QoS AMC

Threading dislocation density comparison between GaN grown on the patterned and conventional sapphire substrate by high resolution X-ray diffraction

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Science china(Physics,Mechanics & Astronomy) 2010年第3期53卷 465-468页

作者： ZHANG YuChao1, XING ZhiGang2, MA ZiGuang2, CHEN Yao2, DING GuoJian2, XU PeiQiang2, DONG ChenMing3, CHEN Hong2 & LE XiaoYun1 1 school of Physics and Nuclear Energy engineering, Beihang university, beijing 100190, {4. 2 Renewable Energy Laboratory, Institute of Physics, Chinese Academy of Sciences, beijing 100190, {4. 3 school of information and communication, Tianjin Polytechnic university, Tianjin 300160, {4. 1. school of Physics and Nuclear Energy engineering Beihang University Beijing 100190 China2. Renewable Energy Laboratory Institute of Physics Chinese Academy of Sciences Beijing 100190 China3. School of Information and Communication Tianjin Polytechnic University Tianjin 300160 China

GaN epifilms are grown on the patterned sapphire substrates (PSS) (0001) and the conventional sapphire substrates (CSS) (0001) by metal-organic chemical vapor deposition (MOCVD) using a novel two-step growth. High resolution X-ray diffraction (HR-XRD) is used to investigate the threading dislocation (TD) density of the GaN epifilms. The TD density is calculated from the ω-scans full width at half maximum (FWHM) results of HR-XRD. The edge dislocation destiny of GaN grown on the PSS is 2.7×108 cm-2, which is less than on the CSS. This is confirmed by the results of atomic force microscopy (AFM) measurement. The lower TD destiny indicates that the crystalline quality of the GaN epifilms grown on the PSS is improved compared to GaN epifilms grown on the CSS. The residual strains of GaN grown on the PSS and CSS are compared by Raman Scattering spectra. It is clearly seen that the residual strain in the GaN grown on PSS is lower than on the CSS.

关键词： GaN patterned sapphire substrate threading dislocation XRD

Dynamic call and connection admission control in automatically switched optical network for grid computing applications

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Science china(information Sciences) 2012年第2期55卷 419-432页

作者： LIU Lei,GUO HongXiang,HONG XiaoBin,WU Jian & LIN JinTong Key Laboratory of information Photonics and Optical communications,Ministry of Education,beijing university of {4. and Telecommunications,beijing 100876,china 1. Key Laboratory of information Photonics and Optical communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

In recent years,Grid computing applications are becoming more and more important to the scientific and business communities and are likely to open to the consumer market and widely develop in the near future,which is a great challenge brought by the potentially large number of Grid users(perhaps millions)and high frequency of their job *** switched optical network(ASON),which is a promising high capacity intelligent transport network infrastructure,has been already deployed in the world and regarded as a promising solution to foster the expansion of Grid computing from local area networks to wide area ***,by theoretical analysis and simulative evaluation of Grid job blocking in the distributed call and connection setup process of ASON,this paper verifies that ASON and the conventional admission control mechanism confront a problem in supporting future large-scale Grid *** order to address this issue,a novel dynamic call and connection admission control(DCCAC)scheme is proposed to improve the network performance and guarantee quality of service(QoS)of Grid *** scheme is applicable with complete network information,no network information and partial network *** results show that the DCCAC scheme can improve the efficiency of the network to a great ***,all the analysis and algorithms in this paper are based on ITU-T ASON recommendations,which make the DCCAC scheme more applicable in network engineering for future Grid computing.

关键词： automatically switched optical network(ASON) Grid computing blocking probability call admission control connection admission control

Multi-layer network architecture in support of end-to-end transparent optical connectivities

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Science china(information Sciences) 2011年第3期54卷 674-682页

作者： GUO HongXiang , WU Jian, HONG Xiao Bin & LIN Jin Tong Key Laboratory of information Photonics and Optical communications, Ministry of Education, beijing university of {4. and Telecommunications, beijing 100876, china 1. Key Laboratory of information Photonics and Optical communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

In order to effectively accommodate a wide variety of emerging and future applications with diverse requirements, an intelligent optical network capable of the rapid and resilient delivery of on-demand transparent transmission capacity is required. This paper investigates a multi-layer network architecture where a generalized multiple protocol label switching (GMPLS) controlled transparent wavelength switched optical network (WSON), as the transport core, collaborates with multiple client optical burst switching (OBS) networks distributed at the edge. Dynamic interworking mechanism as well as the related signaling/routing protocol ex- tensions for multi-QoS burst streams transmission among different OBS domains are proposed so as to provision an end-to-end (e2e) transparent optical connectivity with on-demand bandwidth to end-users. Moreover, the survivability of this transparent optical connectivity is also addressed. To validate the feasibility of this architecture, an integrated OBS/WSON network testbed was constructed, and stable e2e transparent connectivities were successfully demonstrated for an efficient multi-QoS burst streams transmission.

关键词： multi-layer network transparent optical network OBS WSON GMPLS

Joint source channel VL coding/decoding for deep space communication networks based on a space trellis

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Science china(information Sciences) 2011年第9期54卷 1883-1894页

作者： WU WeiRen 1,TU Juan 2,TU GuoFang 1,GAO ShaoShuai 1 & ZHANG Can 1,3 1 school of information Science and engineering,Graduate university of Chinese Academy of Sciences,{4. 10004.,china 2 {4. Institute of Electronic System engineering,china Aerospace Science & Industry Corp.,{4. 100854.china 3 State Key Laboratory of information Security,Graduate university of Chinese Academy of Science,{4. 10004.,china 1. school of information Science and engineering Graduate University of Chinese Academy of Sciences Beijing 100049 China2. Beijing Institute of Electronic System Engineering China Aerospace Science & Industry Corp. Beijing 100854 China3. State Key Laboratory of Information Security Graduate University of Chinese Academy of Science Beijing 100049 China

This paper presents joint source channel variable length (VL) coding/decoding based on a space *** constructing a joint decoding plane trellis,better decoding performance can be achieved than by using the bit-level decoding ***,the plane trellis is complicated,which results in high decoding complexity for decoding VL turbo *** solve this problem,we construct a space trellis and design a low-complexity joint decoding algorithm with a variable length symbol-a posteriori probability (VLS-APP) algorithm in resource constrained deep space communication *** results show that the proposed approach reduces the decoding complexity by 10% compared with the plane trellis,and the gain of Eb/N0 is about 0.2 dB at SER=***,it provides substantial error protection for variable-length encoded image data.

关键词： joint coding/decoding VL turbo codes space trellis VLS-APP

Formation control for networked spacecraft in deep space:with or without communication delays and with switching topology

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Science china(information Sciences) 2011年第3期54卷 469-481页

作者： WANG Nan 1,2, ZHANG TianWu 2 & XU JieQiong 1 1 school of Aeronautic Science and engineering, beijing university of Aeronautics and Astronautics, beijing 100191, china 2 Department of Computer Science and engineering, Henan Institute of engineering, Zhengzhou 4.1191, china 1. school of Aeronautic Science and engineering Beijing University of Aeronautics and Astronautics Beijing 100191 China2. Department of Computer Science and Engineering Henan Institute of Engineering Zhengzhou 451191 China

In this paper, several formation controllers are developed with constant and variable connected communication topology for six-degree-of-freedom (6-DOF) networked spacecraft flying in deep space with constant and time-varying communication delays considered. In the control algorithm, any explicit leader does not exist in the formation team and it is required that each spacecraft communicate only with its neighbors and therefore the required communication loads of the whole formation is greatly reduced. The proposed control strategies allow that each spacecraft can track its desired position and attitude and simultaneously the whole group moves to the desired formation and obtain its desired relative attitudes with its neighbors. Simulation results demonstrate the effectiveness of the proposed controllers.

关键词： deep space graph theory formation control communication topology delays

Adaptive subcarrier and bit allocation based on ant colony optimization

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The Journal of china Universities of posts and Telecommunications 2010年第6期17卷 59-64页

作者： ZHAO Ying-hong,XU Xiao-dong,HAO Zhi-jie,TAO Xiao-feng Wireless Technology Innovation Institute,Key Laboratory of Universal Wireless communication,Ministry of Education,beijing university of posts and Telecommunications,beijing 100876,china [a] Wireless Technology Innovation Institute Key Laboratory of Universal Wireless Communication Ministry of Education Beijing University of Posts Telecommunications Beijing 100876 China

The problem of resource allocation in multiuser orthogonal frequency division multiplexing （OFDM） system is a combinatorial optimization problem,difficult to obtain optimal solutions in polynomial time. For the sake of reducing complexity,it can be solved either by relaxing constraints and making use of linear algorithms or by metaheuristic methods. In this paper,an algorithm based on ant colony optimization （ACO）,which is a typical algorithm of metaheuristic methods,is proposed for the problem,utilizing excellent search performance of ACO to obtain good solutions. In addition,a parameter is applied to balance the efficiency and fairness of resource allocation. Performance analysis between algorithms based on ACO and genetic algorithm （GA） is carried out,indicating that the proposed algorithm based on ACO outperforms traditional linear algorithms as well as GA in the system throughput with assurance of fairness simultaneously,being as a promising technology for OFDM resource allocation.

关键词： ACO OFDM GA

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