The Experts below are selected from a list of 12072 Experts worldwide ranked by ideXlab platform

Jie Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Service differentiation-based Spectrum deFragmentation in mixed grid optical networks
    Optical Fiber Technology, 2020
    Co-Authors: Yongli Zhao, Jie Zhang
    Abstract:

    Abstract As the most promising candidate for upgrading today’s fixed-grid networks, the concept of flexible grid has been introduced into elastic optical networks (EONs), which enables on-demand Spectrum assignment and adaptive modulation formats. Considering the cost of network upgrade, it is practical and economical for network operators to adopt the gradual migration from fixed grid to flexible grid optical network. Thus, a mixed grid optical network is a typical network scenario in the near future where fixed grid technology coexists with flexible grid technology. Spectrum Fragmentation is regarded as a significant issue in flexible grid optical network. Compared with flexible grid, with heterogeneous spectral widths, more Spectrum Fragmentation is induced in mixed grid optical networks. Therefore, Spectrum Fragmentation in mixed grid optical network is actually much more challenging than flexible grid optical network. This paper first analyzes the resource allocation and proposes a novel Spectrum deFragmentation algorithm based on service differentiation in mixed grid optical networks. The performance of the proposed algorithm is evaluated in simulation with different traffic profiles. Simulation results verify that the proposed algorithm can effectively reduce the blocking probability by consolidating Spectrum Fragmentation in mixed grid optical networks.

  • OECC/PSC - Service Provisioning based on Association Rules Mining between Crosstalk and Fragmentization in Multi-core Elastic Optical Networks
    2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC), 2019
    Co-Authors: Qiuyan Yao, Hui Yang, Jie Zhang
    Abstract:

    We propose a service provisioning mechanism by mining association rules between crosstalk and Spectrum Fragmentation in elastic optical networks with multi-core fibers. Results indicate our scheme can reduce fragments, decrease blocking, and improve resource utilization.

  • Crosstalk-Aware Spectrum DeFragmentation Based on Spectrum Compactness in Space Division Multiplexing Enabled Elastic Optical Networks With Multicore Fiber
    IEEE Access, 2018
    Co-Authors: Yongli Zhao, Ruijie Zhu, Xinbo Wang, Jie Zhang
    Abstract:

    Achievable capacity of optical fiber is approaching its physical limitation in frequency domain. Space division multiplexing (SDM) technology can scale the network capacity using multi-core fiber and multi-mode fiber. In order to provide high-speed transmission services with fine granularities, SDM enabled elastic optical networks (SDM-EONs) become a promising candidate of future optical transport networks. However, since the Spectrum status in SDM-EONs becomes more complex with the introduction of spatial dimension, the issue of Spectrum Fragmentation will be more serious in SDM-EONs compared in simple EONs. To remedy the issue of Spectrum Fragmentation in SDM-EONs, we propose a crosstalk-aware Spectrum deFragmentation (CASD) algorithm based on a metric, i.e., Spectrum compactness (SC), which we define to measure the Spectrum status in the SDM-EONs. Simulation results show that the proposed CASD algorithm can achieve better performance than a benchmark algorithm in terms of blocking probability and Spectrum utilization. We also compare CASD algorithm with different SC thresholds in bandwidth blocking probability and Spectrum utilization. Among them, CASD algorithm with SC threshold of 50 performs the best. It can achieve low Spectrum moving times as well as low deFragmentation latency.

  • Multi-core virtual concatenation scheme considering inter-core crosstalk in spatial division multiplexing enabled elastic optical networks
    China Communications, 2017
    Co-Authors: Yongli Zhao, Ruijie Zhu, Chunhui Wang, Jie Zhang
    Abstract:

    Spatial division multiplexing enabled elastic optical networks (SDM-EONs) are the potential implementation form of future optical transport networks, because it can curve the physical limitation of achievable transmission capacity in single-mode fiber and single-core fiber. However, Spectrum Fragmentation issue becomes more serious in SDM-EONs compared with simple elastic optical networks (EONs) with single mode fiber or single core fiber. In this paper, multi-core virtual concatenation (MCVC) scheme is first proposed considering inter-core crosstalk to solve the Spectrum Fragmentation issue in SDM-EONs. Simulation results show that the proposed MCVC scheme can achieve better performance compared with the baseline scheme, i.e., single-core virtual concatenation (SCVC) scheme, in terms of blocking probability and Spectrum utilization.

  • Crosstalk-aware cross-core virtual concatenation in spatial division multiplexing elastic optical networks
    Electronics Letters, 2016
    Co-Authors: Yongli Zhao, Jie Zhang
    Abstract:

    Spatial division multiplexing elastic optical networks (SDM-EONs) will become the most important form of future optical transport networks, because it can break the physical limit of achievable capacity in single-mode and single-core fibre. However, Spectrum Fragmentation issue becomes more serious in SDM-EONs compared with in single EON. Crosstalk-aware cross-core virtual concatenation (CCVC) scheme is first proposed to solve the Spectrum Fragmentation issue in SDM-EONs. Simulation results show that CCVC can achieve lower blocking probability and higher Spectrum utilisation compared with single-core virtual concatenation scheme.

Yongli Zhao - One of the best experts on this subject based on the ideXlab platform.

  • Service differentiation-based Spectrum deFragmentation in mixed grid optical networks
    Optical Fiber Technology, 2020
    Co-Authors: Yongli Zhao, Jie Zhang
    Abstract:

    Abstract As the most promising candidate for upgrading today’s fixed-grid networks, the concept of flexible grid has been introduced into elastic optical networks (EONs), which enables on-demand Spectrum assignment and adaptive modulation formats. Considering the cost of network upgrade, it is practical and economical for network operators to adopt the gradual migration from fixed grid to flexible grid optical network. Thus, a mixed grid optical network is a typical network scenario in the near future where fixed grid technology coexists with flexible grid technology. Spectrum Fragmentation is regarded as a significant issue in flexible grid optical network. Compared with flexible grid, with heterogeneous spectral widths, more Spectrum Fragmentation is induced in mixed grid optical networks. Therefore, Spectrum Fragmentation in mixed grid optical network is actually much more challenging than flexible grid optical network. This paper first analyzes the resource allocation and proposes a novel Spectrum deFragmentation algorithm based on service differentiation in mixed grid optical networks. The performance of the proposed algorithm is evaluated in simulation with different traffic profiles. Simulation results verify that the proposed algorithm can effectively reduce the blocking probability by consolidating Spectrum Fragmentation in mixed grid optical networks.

  • Crosstalk-Aware Spectrum DeFragmentation Based on Spectrum Compactness in Space Division Multiplexing Enabled Elastic Optical Networks With Multicore Fiber
    IEEE Access, 2018
    Co-Authors: Yongli Zhao, Ruijie Zhu, Xinbo Wang, Jie Zhang
    Abstract:

    Achievable capacity of optical fiber is approaching its physical limitation in frequency domain. Space division multiplexing (SDM) technology can scale the network capacity using multi-core fiber and multi-mode fiber. In order to provide high-speed transmission services with fine granularities, SDM enabled elastic optical networks (SDM-EONs) become a promising candidate of future optical transport networks. However, since the Spectrum status in SDM-EONs becomes more complex with the introduction of spatial dimension, the issue of Spectrum Fragmentation will be more serious in SDM-EONs compared in simple EONs. To remedy the issue of Spectrum Fragmentation in SDM-EONs, we propose a crosstalk-aware Spectrum deFragmentation (CASD) algorithm based on a metric, i.e., Spectrum compactness (SC), which we define to measure the Spectrum status in the SDM-EONs. Simulation results show that the proposed CASD algorithm can achieve better performance than a benchmark algorithm in terms of blocking probability and Spectrum utilization. We also compare CASD algorithm with different SC thresholds in bandwidth blocking probability and Spectrum utilization. Among them, CASD algorithm with SC threshold of 50 performs the best. It can achieve low Spectrum moving times as well as low deFragmentation latency.

  • Multi-core virtual concatenation scheme considering inter-core crosstalk in spatial division multiplexing enabled elastic optical networks
    China Communications, 2017
    Co-Authors: Yongli Zhao, Ruijie Zhu, Chunhui Wang, Jie Zhang
    Abstract:

    Spatial division multiplexing enabled elastic optical networks (SDM-EONs) are the potential implementation form of future optical transport networks, because it can curve the physical limitation of achievable transmission capacity in single-mode fiber and single-core fiber. However, Spectrum Fragmentation issue becomes more serious in SDM-EONs compared with simple elastic optical networks (EONs) with single mode fiber or single core fiber. In this paper, multi-core virtual concatenation (MCVC) scheme is first proposed considering inter-core crosstalk to solve the Spectrum Fragmentation issue in SDM-EONs. Simulation results show that the proposed MCVC scheme can achieve better performance compared with the baseline scheme, i.e., single-core virtual concatenation (SCVC) scheme, in terms of blocking probability and Spectrum utilization.

  • A Spectrum deFragmentation strategy for service differentiation consideration in elastic optical networks
    Optical Fiber Technology, 2017
    Co-Authors: Qiuyan Yao, Hui Yang, Ruijie Zhu, Hongyun Xiao, Chen Jie, Yingming Jiang, Huang Zhuoyao, Hongsuo Yan, Yongli Zhao
    Abstract:

    Abstract The Spectrum Fragmentation problem remains to be an open issue in elastic optical networks. In addition, the quality of service cannot be ignored during the transmission process. In this paper, we propose a novel Spectrum deFragmentation strategy considering the service differentiation, named SDSD, to improve the network performance in terms of the Spectrum resources utilization, blocking probability (BP), and the set-up time for the serving connections. The presented results show that the proposed scheme can allocate the Spectrum resources efficiently while decreasing the BP and connection set-up time. Moreover, the low grade services will be migrated preferentially during the phase of Spectrum deFragmentation, decreasing the number of migration.

  • Crosstalk-aware cross-core virtual concatenation in spatial division multiplexing elastic optical networks
    Electronics Letters, 2016
    Co-Authors: Yongli Zhao, Jie Zhang
    Abstract:

    Spatial division multiplexing elastic optical networks (SDM-EONs) will become the most important form of future optical transport networks, because it can break the physical limit of achievable capacity in single-mode and single-core fibre. However, Spectrum Fragmentation issue becomes more serious in SDM-EONs compared with in single EON. Crosstalk-aware cross-core virtual concatenation (CCVC) scheme is first proposed to solve the Spectrum Fragmentation issue in SDM-EONs. Simulation results show that CCVC can achieve lower blocking probability and higher Spectrum utilisation compared with single-core virtual concatenation scheme.

Fang Wang - One of the best experts on this subject based on the ideXlab platform.

  • Spectrum access strategies based on the ratio of throughput to Spectrum consumption in the context of Spectrum Fragmentation in distributed cognitive radio networks
    International Conference on Conceptual Structures, 2014
    Co-Authors: Shuai Zhang, Fang Wang
    Abstract:

    Because of the random presence of primary users in cognitive radio networks, the available Spectrums are fragmented with the size of each fragment varying from one channel to several channels. Due to the Spectrum Fragmentation, the cross-band interference between spectrally adjacent users is considered harmful in the distributed cognitive radio networks. To eliminate the interference, frequency guard-bands are inserted between Spectrum fragments. The guard-bands not used for transmission are considered as the Spectrum consumption. Accordingly, the achieved throughput is at the cost of the guard-bands consumption. Thus, to utilize the Spectrum fragments efficiently, the ratio of throughput to Spectrum consumption is defined for the dynamic Spectrum access problem. Therefore, under the conditions of prescribed user quality-of-service (QoS) requirements and the frequency agility limit, a novel mathematic model in which the ratio of throughput to Spectrum consumption is maximized is proposed in this paper, which is an integer programming problem. To this end, three Spectrum access strategies with lower complexities than the traditional exhaustive search are proposed. Simulation results show that the ratio can be used as the index whether the Spectrum fragments are effectively utilized. Meanwhile, the Spectrum consumption is mainly affected by the size of guard-band, number of fragments and available channels, so the ratios are varying with these factors. Moreover, as the different Spectrum utilizations of the four strategies, these factors also have significant influences on the performances of the strategies.

  • ICCS - Spectrum access strategies based on the ratio of throughput to Spectrum consumption in the context of Spectrum Fragmentation in distributed cognitive radio networks
    2014 IEEE International Conference on Communication Systems, 2014
    Co-Authors: Shuai Zhang, Fang Wang
    Abstract:

    Because of the random presence of primary users in cognitive radio networks, the available Spectrums are fragmented with the size of each fragment varying from one channel to several channels. Due to the Spectrum Fragmentation, the cross-band interference between spectrally adjacent users is considered harmful in the distributed cognitive radio networks. To eliminate the interference, frequency guard-bands are inserted between Spectrum fragments. The guard-bands not used for transmission are considered as the Spectrum consumption. Accordingly, the achieved throughput is at the cost of the guard-bands consumption. Thus, to utilize the Spectrum fragments efficiently, the ratio of throughput to Spectrum consumption is defined for the dynamic Spectrum access problem. Therefore, under the conditions of prescribed user quality-of-service (QoS) requirements and the frequency agility limit, a novel mathematic model in which the ratio of throughput to Spectrum consumption is maximized is proposed in this paper, which is an integer programming problem. To this end, three Spectrum access strategies with lower complexities than the traditional exhaustive search are proposed. Simulation results show that the ratio can be used as the index whether the Spectrum fragments are effectively utilized. Meanwhile, the Spectrum consumption is mainly affected by the size of guard-band, number of fragments and available channels, so the ratios are varying with these factors. Moreover, as the different Spectrum utilizations of the four strategies, these factors also have significant influences on the performances of the strategies.

Chengying Wei - One of the best experts on this subject based on the ideXlab platform.

  • A Spectrum-efficient algorithm based on traffic splitting and merging transmission for anycast in inter-datacenter elastic optical networks
    Photonic Network Communications, 2018
    Co-Authors: Chengying Wei, Huanlin Liu, Xiong Cuilian, Yong Chen
    Abstract:

    Anycast is attracting much attention due to the need of scalable and cost-effective data delivery in inter-datacenter elastic optical networks. However, Spectrum Fragmentation degrades network’s performance and decreases probability of successful anycast delivery significantly. When the idle Spectrum block in elastic optical network is not enough to transmit the anycast request, Spectrum splitting with multi-path transmitting the anycast is an effective approach to improve the Spectrum Fragmentation utilization. For improving Spectrum utilization and reducing time delay between multiple paths, we propose a Spectrum-efficient algorithm based on traffic splitting and merging (Anycast_SA_TSM) transmission to avoid Spectrum Fragmentation and delay between multiple paths. In order to minimize the time delay between multiple paths, we design a modified scheme to select the multiple paths with minimal time delay to transmit the anycast. During the Spectrum allocation phase, a new Spectrum block allocation scheme, the exact fit or Fragmentation minimal, is put forward. Moreover, when an appropriate size of Spectrum block is found for the split anycast request, merging split sub-requests to a single path is activated for minimizing the additional guard bands and improving the Spectrum efficiency. Comparing with other two anycast algorithms, simulation results show that the proposed algorithm can get minimal time delay between split multiple paths, the minimal bandwidth blocking probability and the highest Spectrum utilization.

  • Fragmentation-Avoiding Spectrum Assignment Strategy Based on Spectrum Partition for Elastic Optical Networks
    IEEE Photonics Journal, 2017
    Co-Authors: Huanlin Liu, Yong Chen, Chengying Wei
    Abstract:

    A Fragmentation-avoiding Spectrum assignment strategy based on Spectrum partition is proposed, which is used to resolve the Spectrum Fragmentation problem in elastic optical networks. For alleviating Spectrum Fragmentation, a Spectrum partition policy, splitting the whole optical Spectrum into several dedicated partitions, is presented. Based on this, a joint first-last-fit Spectrum assignment policy is presented to enhance the probability of successful transmission of request and Spectrum efficiency, where each partition is first used to transmit requests with the same rate in the first-fit policy; and other partitions are used to search available Spectrum resources in the last-fit policy when there are no available Spectrum resources in the dedicated partition. Meanwhile, a partition selection formula is designed to minimize the interference of Spectrum resources during the last-fit Spectrum assignment. Moreover, a reconfiguration mechanism, moving requests that are not transmitted in their dedicated partition to their dedicated partition, is also studied. The simulation results indicate that the proposed algorithm can reduce the bandwidth blocking probability and improve Spectrum efficiency.

Ruijie Zhu - One of the best experts on this subject based on the ideXlab platform.

  • Time and Spectrum Fragmentation-aware virtual optical network embedding in elastic optical networks
    Optical Fiber Technology, 2020
    Co-Authors: Ruijie Zhu, Peisen Wang, Junling Yuan
    Abstract:

    Abstract Based on the concept of infrastructure as a service, optical network virtualization can improve the efficiency of network infrastructure by sharing the physical substrate network among different tenants and applications. The most important issue of optical network virtualization is how to handle the virtual optical network embedding (VONE) process, especially with the coexistence of the requests those can be reserved in advance (AR) and those require immediate reservation (IR). To address this issue, we investigate the time and Spectrum Fragmentation during the VONE process, which undermines the embedding success rate in elastic optical networks. A two-dimensional Fragmentation measurement is first proposed to evaluate the resource state. Then we design a Two-Dimensional Fragmentation Aware (TDFA) VONE algorithm, and a Fragmentation and Continuity Aware (FCA) VONE algorithm, which decreases the two-dimensional Fragmentation in the VONE process. Simulation results show that the proposed algorithms perform better than the baseline algorithm in blocking probability and Spectrum utilization issues.

  • Crosstalk-Aware Spectrum DeFragmentation Based on Spectrum Compactness in Space Division Multiplexing Enabled Elastic Optical Networks With Multicore Fiber
    IEEE Access, 2018
    Co-Authors: Yongli Zhao, Ruijie Zhu, Xinbo Wang, Jie Zhang
    Abstract:

    Achievable capacity of optical fiber is approaching its physical limitation in frequency domain. Space division multiplexing (SDM) technology can scale the network capacity using multi-core fiber and multi-mode fiber. In order to provide high-speed transmission services with fine granularities, SDM enabled elastic optical networks (SDM-EONs) become a promising candidate of future optical transport networks. However, since the Spectrum status in SDM-EONs becomes more complex with the introduction of spatial dimension, the issue of Spectrum Fragmentation will be more serious in SDM-EONs compared in simple EONs. To remedy the issue of Spectrum Fragmentation in SDM-EONs, we propose a crosstalk-aware Spectrum deFragmentation (CASD) algorithm based on a metric, i.e., Spectrum compactness (SC), which we define to measure the Spectrum status in the SDM-EONs. Simulation results show that the proposed CASD algorithm can achieve better performance than a benchmark algorithm in terms of blocking probability and Spectrum utilization. We also compare CASD algorithm with different SC thresholds in bandwidth blocking probability and Spectrum utilization. Among them, CASD algorithm with SC threshold of 50 performs the best. It can achieve low Spectrum moving times as well as low deFragmentation latency.

  • Multi-core virtual concatenation scheme considering inter-core crosstalk in spatial division multiplexing enabled elastic optical networks
    China Communications, 2017
    Co-Authors: Yongli Zhao, Ruijie Zhu, Chunhui Wang, Jie Zhang
    Abstract:

    Spatial division multiplexing enabled elastic optical networks (SDM-EONs) are the potential implementation form of future optical transport networks, because it can curve the physical limitation of achievable transmission capacity in single-mode fiber and single-core fiber. However, Spectrum Fragmentation issue becomes more serious in SDM-EONs compared with simple elastic optical networks (EONs) with single mode fiber or single core fiber. In this paper, multi-core virtual concatenation (MCVC) scheme is first proposed considering inter-core crosstalk to solve the Spectrum Fragmentation issue in SDM-EONs. Simulation results show that the proposed MCVC scheme can achieve better performance compared with the baseline scheme, i.e., single-core virtual concatenation (SCVC) scheme, in terms of blocking probability and Spectrum utilization.

  • A Spectrum deFragmentation strategy for service differentiation consideration in elastic optical networks
    Optical Fiber Technology, 2017
    Co-Authors: Qiuyan Yao, Hui Yang, Ruijie Zhu, Hongyun Xiao, Chen Jie, Yingming Jiang, Huang Zhuoyao, Hongsuo Yan, Yongli Zhao
    Abstract:

    Abstract The Spectrum Fragmentation problem remains to be an open issue in elastic optical networks. In addition, the quality of service cannot be ignored during the transmission process. In this paper, we propose a novel Spectrum deFragmentation strategy considering the service differentiation, named SDSD, to improve the network performance in terms of the Spectrum resources utilization, blocking probability (BP), and the set-up time for the serving connections. The presented results show that the proposed scheme can allocate the Spectrum resources efficiently while decreasing the BP and connection set-up time. Moreover, the low grade services will be migrated preferentially during the phase of Spectrum deFragmentation, decreasing the number of migration.

  • Dynamic time and Spectrum Fragmentation-aware service provisioning in elastic optical networks with multi-path routing
    Optical Fiber Technology, 2016
    Co-Authors: Ruijie Zhu, Hui Yang, Jie Zhang, Yongli Zhao, Ashkan Yousefpour, Nannan Wang, Jason P. Jue
    Abstract:

    Abstract In this paper, we propose a multi-path Fragmentation-aware routing, modulation and Spectrum assignment algorithm (RMSA) for advance reservation (AR) and immediate reservation (IR) requests in elastic optical networks. Immediate reservation requests should be provided with service immediately, while advance reservation requests have specific starting times and holding times. As lightpaths are set up and torn down, Fragmentation may occur in both Spectrum and time domains. To decrease the two-dimensional Fragmentation and to solve the problem of resource scarcity, we propose splitting requests into different parts and transferring these parts along one or more paths utilizing sliceable bandwidth variable transponders. We first introduce a model to solve the problem and propose a two-dimensional Fragmentation occurrence measurement in Spectrum and time domains. Then we propose a multi-path Fragmentation-aware RMSA algorithm (MPFA). Simulation results show that MPFA can achieve better performance than existing algorithms in terms of blocking probability and Spectrum utilization.