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Analytical Model of Non-dispersion-limited Transient Stimulated Raman Scattering in Single-mode Silica Fiber in WDM Optical Communication System

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Chinese Journal of Lasers 2000年第2期9卷 175-181页

作者： GONG Jiamin FANG Qiang LIU Juan WANG Yongchang (Insitute of Modern Physics, Xi' an Jiaotang university, Xi' an 710049, China Department of telecommunications, Xi' an Institute of posts and telecommunications, Xi' an 710061, China ) 西安交通大学陕西西安西安邮电学院陕西西安

The non-dispersion-limited analytic acutions of unidirectional N-channel transient stimulated Raman scattering (SRS) coupling wave equation which governing the propagation of the optical signals in single-mode (SM) silica fiber have been presented. Taking into account the SRS cross coupling among the N- channels, the analytic solutions are applicable to the system with arbitrary channel separation and input signal light power.

关键词： stimulated Raman scattering (SRS) wavelength division multiplexing (WDM) fused silica fiber Raman amplification Raman crosstalk

Soliton Propagation in Optical Fibers with Random Polarization Dispersion

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Chinese Journal of Lasers 1994年第1期B3卷 49-55页

作者： TANG Xiongyan YE Peida(Department of Radio Engineering,Beijing university,of posts and telecommunications,Beijing 100088, China) Beijing Univ of posts and Telecommunications Beijing China

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关键词： optical communication soliton transmission birefringent fiber polarization dispersion

Novel limited feedback scheme under the MIMO broadcast system

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The Journal of China Universities of posts and telecommunications 2009年第6期16卷 11-16页

作者： CHENG Tie-zheng,YUAN Chao-wei School of Information and Communication Engineering,Beijing university of posts and telecommunications,Beijing 100876,China [a] School of Information and Communication Engineering Beijing university of posts and telecommunications Beijing 100876 China

By deducing the distribution of the normalized channel covariance matrix,a novel limited feedback scheme is proposed under multiple users（MU） multiple-input multiple-output（MIMO） broadcast channel（BC） *** proposed scheme has advantages in three ***,it has no constraints on the number of users or ***,each user＇s feedback bits are independent of the number of receiving ***,the proposed scheme avoids the storage of large-size codebook on the *** results show that the performance of the proposed scheme is close to the perfect channel state information（CSI） case and it just needs a small number of feedback bits.

关键词： MIMO broadcast channel limited feedback normalized channel covariance

Synchronization of MIMO OFDM systems by perfect complete generalized complementary orthogonal loosely synchronous code groups

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The Journal of China Universities of posts and telecommunications 2009年第2期16卷 1-7页

作者： WANG Jian YANG Xun LI Dao-ben School of Information Engineering,Beijing university of posts and telecommunications,Beijing 100876,China [a]School of Information Engineering Beijing university of posts and telecommunications Beijing 100876 China

This article proposes a time/frequency synchronization algorithm in the multiple input multiple output （MIMO） systems, in which the perfect complete generalized complementary orthogonal loosely synchronous code groups are used as the synchronization sequence. The synchronization algorithm is divided into four stages： 1） synchronization in time domain by signal autocorrelation; 2） synchronization in frequency domain by fast Fourier transform （FFT）; 3） multipath dissociation using coherent detection and fine time synchronization; 4） fine frequency offset estimation by phase rotation. As per the perfect complete generalized complementary orthogonal loosely synchronous code groups, the cross-correlation and out-of-phase auto-correlation for any relative shift between any two codes is always zero. This ideal property makes the time/frequency synchronization algorithm simple and efficient. The simulation results show that even in the multipath fast fading channel with low signal noise ratio （SNR）, the MIMO system can get synchronized both in the time domain and frequency domain with high stability and reliability.

关键词： MIMO OFDM synchronization complementary orthogonal code loosely synchronous (LS) code

The influence of higher-order effects on the transmission performances of the ultra-short soliton pulses and its suppression method

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Science China(Information Sciences) 2010年第1期53卷 182-190页

作者： ZHU Bo & YANG XiangLin Institute of Optical Communication, Nanjing university of posts and telecommunications, Nanjing 210003, China 1. Institute of Optical Communication Nanjing University of Posts and Telecommunications Nanjing 210003 China

Under the condition of the higher order effects, a propagation equation is established to investigate the way to suppress the soliton self frequency shift and timing jitter in the picosecond and femtosecond soliton communication system using a combined control method of time domain and frequency domain. By the use of the variational approach, the evolution of the chirping Gaussian quasi-soliton pulse is analyzed in the presence of the effects including third order dispersion, intrapulse Raman scattering (IRS), and self steepening. Considering the soliton evolution properties and the mechanism of the timing jitter under the higher-order effects, the combined control method is adopted to eliminate the influence from Raman scattering and self-steepening. The soliton central frequency is stabilized and the timing jitter is suppressed effectively. A 160 Gb/s long-haul soliton transmission system is designed and its performance is numerically simulated. The simulation results are in good agreement with our theoretical analysis.

关键词： high rate soliton communication higher-order nonlinearity Raman self-frequency shift transmission control stable transmission

Multi-function Device Based on Two Terahertz Optical Asymmetric Demutiplexers

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Chinese Journal of Lasers 1999年第5期8卷 3-5页

作者： HONG Xiaobin LIN Jintong(Optical Communication R & D Center, Beijing university of posts and telecommunications, Beijing 100876, China) 北京邮电大学光通信R&D中心北京 100876 北京邮电大学光通信R&D中心北京

A multi-function device based on two terahertz optical asymmeric demultiplexers (TOAD) is proposed, which can be used simultancously as demultiplexing, data regeneration,clock recovery and wavelength conversion unit. The device can work at an ultra-high speed optical time-division multiplexing (OTDM) system with relativey low speed components.

关键词： OTDM clock recovery phase-lock loop (PLL) terahertz optical asymmetric demultiplexer (TOAD) data regeneration wavelength conversion

Key technologies of new malicious code developments and defensive measures in communication networks

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The Journal of China Universities of posts and telecommunications 2010年第4期17卷 69-73页

作者： LI Peng,WANG Ru-chuan ,ZHANG Wei College of Computer,Nanjing university of posts and telecommunications,Nanjing 210003,China [a] College of Computer Nanjing University of Posts telecommunications Nanjing 210003 China

This article is focused on analyzing the key technologies of new malicious code and corresponding defensive measures in the large-scale communication networks. Based on description of the concepts and development of the malicious code, the article introduces the anti-analysis technology, splitting and inserting technology, hiding technology, polymorph virus technology, and auto production technology of the malicious code trends with intelligence, diversity and integration. Following that, it summarizes the security vulnerabilities of communication networks from four related layers aspects, according to the mechanisms of malicious code in the communication networks. Finally, it proposes rapid response disposition of malicious code attacks from four correlated steps： building up the network node monitoring system, suspicious code feature automation analysis and extraction, rapid active malicious code response technique for unknown malicious code, and malicious code attack immunity technique. As a result, it actively defenses against the unknown malicious code attacks and enhances the security performance of communication networks.

关键词： network security malicious code network attack and defense malicious code defense

Channel estimation in space and frequency domain for MIMO-OFDM systems

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The Journal of China Universities of posts and telecommunications 2009年第3期16卷 40-44页

作者： PAN Pei-sheng,ZHENG Bao-yu College of Communication and Information,Nanjing university of posts and telecommunications,Nanjing 210003,China [a]College of Communication and Information Nanjing university of posts and telecommunications Nanjing 210003 China

Multiple-input multiple-output （MIMO） systems can be combined with orthogonal frequency division multiplexing （OFDM） systems to improve the capacity and quality of wireless communications. In this article, a channel estimation technique in both space and frequency domain for MIMO-OFDM systems is proposed. It is shown that the proposed scheme with space-frequency pilot tones achieve optimal minimum mean square error （MMSE） channel estimation. Simulation results indicate that the proposed method achieves good performance.

关键词： channel estimation MIMO OFDM space frequency pilot tones

Resource scheduling scheme with QoS support in two-hop relay-enhanced OFDMA systems

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The Journal of China Universities of posts and telecommunications 2010年第4期17卷 26-30页

作者： LIU Wei ,JI Hong,LI Ting School of Information and Telecommunication Engineering,Beijing university of posts and telecommunications,Beijing 100876,China [a] School of Information Telecommunication Engineering Beijing University of Posts telecommunications Beijing 100876 China

As the system performance is obviously improved by introducing the concept of relay into the traditional orthogonal frequency division multiple access （OFDMA） systems, resource scheduling in relay-enhanced OFDMA systems is worthy of being studied carefully. To solve the optimization problem of achieving the maximum throughput while satisfying the quality of service （QoS） and guaranteeing the fairness of users, a novel resource scheduling scheme with QoS support for the downlink of two-hop relay-enhanced OFDMA systems is proposed. The proposed scheme, which is considered both in the first time sub-slot between direct link users and relay stations, and the second time sub-slot among relay link users, takes QoS support into consideration, as well as the system throughput and the fairness for users. Simulation results show that the proposed scheme has good performance in maximizing system throughput and guaranteeing the performance in the service delay and the data loss rate.

关键词： relay OFDMA QoS resource scheduling