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Novel disjoint path selection scheme based on link availability in ASON

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The Journal of China Universities of Posts and Telecommunications 2007年第3期14卷 70-73页

作者： WANG Xian-qing LU yue-ming ji yue-feng Key Laboratory of Optical Communication and Lightwave Technologies Ministry of Education Beijing University of Posts and TelecommunicationsBeijing 100876 China

Risk-disjoint routing is an efficient way to improve network survivability. In this article, a partial risk-disjoint routing algorithm based on link availability （PRDRA-LA） is proposed based on the complete risk-disjoint routing algorithm （CRDRA）. While calculating the protection path with PRDRA-LA, the links that share risks with the links in the working path are filtered by link availability. In addition, the risk disjoint degree between the protection path and the working path can be adjusted freely. Simulation results showed that when compared with CRDRA, routing connections with PRDRA-LA can achieve improved survivability while the number of connections that can be successfully routed over the current network is kept from serious decline.

关键词： automatically switched optical network risk- sharing links partial risk-disjoint routing algorithm based on link availability risk-disjoint degree

QoS multicast routing scheme using QGA in IP/DWDM networks

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The Journal of China Universities of Posts and Telecommunications 2008年第4期15卷 95-100页

作者： XING Huan-lai BAI Lin ji yue-feng Key Laboratory of Optical Communications and Lightwave Techno ogies Beijing University of Posts and Telecommunications Beijing 100876 China

This article studies multi-constraints least-cost multicast routing problem in internet protocol over dense wavelength division multiplexing （IP/DWDM） networks. To address this problem, an individual-difference-based quantum genetic algorithm （IDQGA） is proposed. This algorithm considers individual differences among chromosomes by introducing an adaptive rotation angle step determination scheme and a grouping-based quantum mutation operation. Simulations are conducted over network topologies. The results indicate that compared with other heuristic algorithms, IDQGA has better optimal performance on solving quality of service （QoS） multicast routing problem in IP/DWDM networks and is characterized by strong robustness, high success ratio and excellent capability on global searching.

关键词： IP-over-DWDM multicast QoS quantum genetic algorithm

Supporting multi-user real-time VBR video service using dynamic bandwidth management based on prediction

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The Journal of China Universities of Posts and Telecommunications 2009年第6期16卷 64-71页

作者： XU Zhi-yuan LI Hui LU yue-ming ji yue-feng Key Laboratory of Optical Communications and Lightwave Technologies Beijing University of Posts and Telecommunications Beijing 100876 China

Real-time variable bit rate（VBR） video is expected to take a significant portion of multimedia ***,plentiful challenges to VBR video service provision have been raised for its characteristic of high traffic *** support multi-user real-time VBR video transmission with high bandwidth utilization and satisfied quality of service（QoS）,this article proposes a practical dynamic bandwidth management *** scheme forecasts future media rate of VBR video by employing time-domain adaptive linear predictor and using media delivery index（MDI） as both QoS measurement and complementary management *** addition,to support multi-user application,an adjustment priorities classified strategy is also put ***,a test-bed based on this management scheme is *** experimental results demonstrate that the scheme proposed in this article is efficient with bandwidth utilization increased by 20%-60% compared to a fixed service rate and QoS guaranteed.

关键词： dynamic bandwidth management MDI QoS real-time time-domain adaptive linear predictor VBR video

Resources allocation in an Intserv/Diffserv integrated EPON system

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The Journal of China Universities of Posts and Telecommunications 2009年第3期16卷 108-113,121页

作者： LIU Qiong LI Hui ji yue-feng QIAO Yao-jun Key Laboratory of Optical Communications and Lightwave Technologies Beijing University of Posts and Telecommunications Beijing 100876 China

As one of the most promising next-generation access network （EPON） should pay more attention to its quality of service （QoS）, techniques, the user-oriented Ethernet passive optical network However, now the EPON adopts mostly differentiated services model （Diffserv） that only provides quality control on traffic aggregation, whereas, the quality of user session cannot be guaranteed when the network is overloaded with substantial connections. This article proposes to apply integrated services model （Intserv） in Diffserv-based EPON, which uses per-flow processing to guarantee QoS. In the simulation, a framework of combined Diffserv and Intserv model is employed in an EPON system, with a dynamic bandwidth allocation algorithm that adapts to it. The simulation results demonstrate that the EPON system with the combined models can provide more flexible, various control for user-oriented service quality.

关键词： QoS Intserv Diffserv resource reservation

The Gordon–Mollenauer Effect in 112 Gbit/s DP-QPSK Systems

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Chinese Physics Letters 2013年第8期30卷 70-73页

作者： QIAO Yao-Jun ZHOU ji QIAN Wen-Hui ji yue-feng State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and TelecommunicationsBeijing 100876

Gordon and Mollenauer(G-M)proposed in 1990 that the interplay between the nonlinear Kerr effect and amplified spontaneous emission noise can generate an enhanced level of noise and degrade the performance of optical phase-modulated *** systematically investigate the G-M effect in 112 Gbit/s coherent dual polarization quaternary phase shift keying(DP-QPSK)systems through comprehensive *** results show that in the presence or absence of inline dispersion compensation,the G-M effect will seriously damage the system *** of our important conclusions are listed as follows:with the increase in the input power into each span,the G-M effect is enhanced simultaneously;the smaller the span length,the stronger the G-M effect caused by more inter-span interaction;for non-zero dispersion-shifted fibers,different coefficient values will cause a similar amount of G-M effect penalty;by comparing the system performance with different dispersion compensation ratios,one can conclude that different residual dispersions of the same magnitude,no matter whether they are under-compensated or over-compensated,can derogate the overall system performance to a similar *** brief,the G-M effect cannot be *** also have a short discussion on how to reduce and compensate for the G-M effect in DP-QPSK systems.

关键词： QPSK polarization dispersion

Load balance in hierarchical routing network

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The Journal of China Universities of Posts and Telecommunications 2009年第6期16卷 72-77页

作者： HUA Yi-qiang LIU Ai-bo LU yue-ming LI Hui ji yue-feng Key Laboratory of Information Photonics and Optical Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China Cisco Systems Inc. China Beijing 100022 China

In this article,the problem of load balance in hierarchical routing network is *** conventional shortest path first（SPF） algorithm over aggregated topology in hierarchical routing network may result in worse routing performance,a traffic sharing path selection algorithm and a variable weight scheme are put forward for hierarchical routing network,which can equilibrate the utilities of link resources and reduce the blocking probability of connections with the improvement on *** are conducted to evaluate proposed variable weight and traffics balance（VWTB） algorithm,which combines traffic sharing and variable *** the simulation results,it can be found that the proposed VWTB algorithm can balance the traffics and equilibrate the utilities of link resources significantly.

关键词： hierarchical routing load balance variable weight traffic sharing

Fiber Nonlinearity Post-Compensation by Optical Phase Conjugation for 40Gb/s CO-OFDM Systems

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Chinese Physics Letters 2011年第6期28卷 164-167页

作者： QIAO Yao-Jun LIU Xue-Jun ji yue-feng Key Laboratory of Information Photonics and Optical Communications(Ministry of Education) Beijing University of Posts and TelecommunicationsBeijing 100876

Fiber nonlinearity impairments in a 40-Gb/s coherent optical orthogonal frequency division multiplexing(CO-OFDM)system are post-compensated for by a new method of fiber nonlinearity post-compensation(FNPC).The FNPC located before the CO-OFDM receiver includes an optical phase conjugation(OPC)unit and a subsequent 80-km-high nonlinear fiber(HNLF)as a fiber nonlinearity *** OPC unit is based on a four wave mixing effect in a semiconductor optical *** fiber nonlinearity impairments in the transmission link are post-compensated for after OPC by transmission through the HNLF with a large nonlinearity *** results show that the nonlinear threshold(NLT)(for Q>10 dB)can be increased by about 2.5 dB and the maximum Q factor is increased by about 1.2 dB for the single−channel 40-Gb/s CO-OFDM system with periodic dispersion *** the 50-GHz channel spacing wavelength-division-multiplexing system,the NLT increases by 1.1 dB,equating to a 0.7 dB improvement for the maximum Q factor.

关键词： fiber amplifier nonlinearity

Shared p-cycles design for dual link failure restorability in optical WDM networks

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The Journal of China Universities of Posts and Telecommunications 2007年第3期14卷 74-78页

作者： XIE Zheng-cheng XING Jun-wei WU Li ji yue-feng Key Laboratory of Optical Communications and Lightwave Technologies Beijing University of Posts and Telecommunications Beijing 100876 China

Pre-configured cycles （p-cycles） can attain high capacity efficiency and fast protection switching times in wavelength division multiplexing （WDM） networks. This article proposes the weighted straddling link algorithm（WSLA） for generating a subset of all cycles that can guarantee 100% restorability in case of dual link failure, and give an integer linear programming（1LP） formulation that solves the shared p-cycles design problem minimizing the total spare capacities. Numerical result shows that our method can achieve 100% dual link failure restorability with acceptable spare capacity. The larger standard deviation of demand set and the larger node degree network, the better the shared p-cycles scheme performs.

关键词： dual link failure p-cycles WDM

Enhanced solutions for resource conflict in GMPLS controlled optical network

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The Journal of China Universities of Posts and Telecommunications 2008年第3期15卷 123-127页

作者： HUANG Zhi-tong HUA Yi-qiang LU yue-ming ji yue-feng, XU Da-xiong Key Laboratory of Optical Communications and Lightwave Technologies Beijing University of Posts and Telecommunications Beijing 100876 China

This article discusses the issue of resource conflict in the generalized multi-protocol label switching （GMPLS） controlled optical network. Based on the analysis of the current random rebuilding mechanism and its drawbacks, this article presents two enhanced solutions for improvement, namely, the priority-based resource allocation mechanism and the network management system （NMS） based sequential resource allocation mechanism. Experimental results show that the presented mechanisms perform better than the original random rebuilding solution in terms of the connection setup/recovery time and successful rate.

关键词： GMPLS automatically switched optical network (ASON) resource reservation protocol (RSVP) control plane resource conflict