It's promising to use Software-Defined Networking(SDN) and Network Functions Virtualization(NFV) to integrate satellite and terrestrial networks. To construct network service function chains in such a multi-domain...It's promising to use Software-Defined Networking(SDN) and Network Functions Virtualization(NFV) to integrate satellite and terrestrial networks. To construct network service function chains in such a multi-domain environment, we propose a horizontal-based Multi-domain Service Function Chaining(Md-SFC) orchestration framework. In this framework, multi-domain orchestrators can coordinate with each other to guarantee the end-to-end service quality. Intra-domain orchestrators also coordinate SDN controllers and NFV management components to implement intra-domain service function chains. Based on this, we further propose a heuristic SFC mapping algorithm with a cooperative inter-domain path calculation method to map service function chains to infrastructures. In this method, master multi-domain orchestrator and intra-domain orchestrators coordinate to select proper inter-domain links. We compare the cooperative method with a naive uncooperative way that domains' topology information is provided to the master multi-domain orchestrator and it calculates the shortest inter-domain path between intra-domain service function chains directly. Simulation results demonstrate that our solution is feasible. It is able to construct end-to-end performance guaranteed service function chain by horizontal-based cooperation. The cooperative inter-domain path calculation method decreasesthe mapping load for the master orchestrator and gets the same end-to-end performance.展开更多
Owing to the potential for intercell cochannel interference mitigation and significant spectral efficiency improvement, coordinating transmission techniques by multiple radio access points have recently attracted a lo...Owing to the potential for intercell cochannel interference mitigation and significant spectral efficiency improvement, coordinating transmission techniques by multiple radio access points have recently attracted a lot of attention. In this paper, the system structure and mathematical signal model based on clustered structure are presented for multipoint coordinating downlink transmission, the clustered supercell configurations with static/dynamic approaches are discussed, and then optimal precod- ing design is provided for an accepted level of scheduling complexity and reduced signaling over- head. Some simulation results are given to evaluate the performance of different cell-clustering approaches, and to show that a clustered supercell size of 7 is a reasonable choice for clustered coordination with the given transmit power and the reduced feedback.展开更多
In Elastic Optical Networks(EONs)with flexible bandwidth allocation,the blocking probability is high because of spectral contention.Similar to the functionality of wavelength conversion in Wavelength-Division-Multiple...In Elastic Optical Networks(EONs)with flexible bandwidth allocation,the blocking probability is high because of spectral contention.Similar to the functionality of wavelength conversion in Wavelength-Division-Multiplexing(WDM)networks,waveband conversion has been proposed to solve spectral contention in EONs.In this paper,we discuss the design of node architectures for an EON with waveband conversion.Four node architectures with shared Tuneable Waveband Converters(TWBCs)are proposed,and their blocking performances are evaluated by simulation.Simulation results show that the blocking probability of a node is significantly improved by waveband conversion.The sharing efficiency of waveband converters is also investigated.Simulation results show that at the same blocking rate,the node architecture with converters shared per node can save more than 20% waveband converters compared with that of the one with converters shared per link.展开更多
基金supported by National High Technology of China ("863 program") under Grant No. 2015AA015702NSAF under Grant No.U1530118+1 种基金NSFC under Grant No.61602030National Basic Research Program of China ("973 program")under Grant No. 2013CB329101
文摘It's promising to use Software-Defined Networking(SDN) and Network Functions Virtualization(NFV) to integrate satellite and terrestrial networks. To construct network service function chains in such a multi-domain environment, we propose a horizontal-based Multi-domain Service Function Chaining(Md-SFC) orchestration framework. In this framework, multi-domain orchestrators can coordinate with each other to guarantee the end-to-end service quality. Intra-domain orchestrators also coordinate SDN controllers and NFV management components to implement intra-domain service function chains. Based on this, we further propose a heuristic SFC mapping algorithm with a cooperative inter-domain path calculation method to map service function chains to infrastructures. In this method, master multi-domain orchestrator and intra-domain orchestrators coordinate to select proper inter-domain links. We compare the cooperative method with a naive uncooperative way that domains' topology information is provided to the master multi-domain orchestrator and it calculates the shortest inter-domain path between intra-domain service function chains directly. Simulation results demonstrate that our solution is feasible. It is able to construct end-to-end performance guaranteed service function chain by horizontal-based cooperation. The cooperative inter-domain path calculation method decreasesthe mapping load for the master orchestrator and gets the same end-to-end performance.
文摘Owing to the potential for intercell cochannel interference mitigation and significant spectral efficiency improvement, coordinating transmission techniques by multiple radio access points have recently attracted a lot of attention. In this paper, the system structure and mathematical signal model based on clustered structure are presented for multipoint coordinating downlink transmission, the clustered supercell configurations with static/dynamic approaches are discussed, and then optimal precod- ing design is provided for an accepted level of scheduling complexity and reduced signaling over- head. Some simulation results are given to evaluate the performance of different cell-clustering approaches, and to show that a clustered supercell size of 7 is a reasonable choice for clustered coordination with the given transmit power and the reduced feedback.
基金supported by the National Key Basic Research Program of China (973 Program) under Grants No. 2010CB328201,No.2010CB328202the National Natural Science Foundation of China under Grants No. 60907030,No. 61275071,No. 60736003,No. 60931160439the National High Technical Research and Development Program of China (863 Program)under Grant No. 2011AA01A106
文摘In Elastic Optical Networks(EONs)with flexible bandwidth allocation,the blocking probability is high because of spectral contention.Similar to the functionality of wavelength conversion in Wavelength-Division-Multiplexing(WDM)networks,waveband conversion has been proposed to solve spectral contention in EONs.In this paper,we discuss the design of node architectures for an EON with waveband conversion.Four node architectures with shared Tuneable Waveband Converters(TWBCs)are proposed,and their blocking performances are evaluated by simulation.Simulation results show that the blocking probability of a node is significantly improved by waveband conversion.The sharing efficiency of waveband converters is also investigated.Simulation results show that at the same blocking rate,the node architecture with converters shared per node can save more than 20% waveband converters compared with that of the one with converters shared per link.
