Research On Spectrum Resource Optimization Of Space Division Multiplexing Elastic Optical Networks

With the emergence of a large number of bandwidth-demand services,network traffic increases exponentially.The space division multiplexing elastic optical network based on multi-core fiber has become one of the effective methods to solve the capacity crisis by the superiority of its theoretically unlimited capacity and high resource utilization.However,the fragmentation issue in elastic optical networks always restricts the improvement of spectrum utilization,and the introduction of spatial dimension leads to the intensified impact of crosstalk issues on services.These two issues affect network performance together.The network environment becomes more complex since both crosstalk and fragmentation are related to spectrum resources.Measuring network resources by a single dimension cannot meet the needs of the current network environment.At the same time,the correlation between the crosstalk issue and the fragmentation issue makes it necessary to consider them comprehensively when optimizing the network.Therefore,how to measure the network environment through multiple dimensions and consider the crosstalk issue and the fragmentation issue has become the focus of the research field.In this context,focusing on how to comprehensively consider crosstalk and fragmentation,this thesis explores the correlation between crosstalk and fragmentation,and comprehensively improves the overall performance of the network by constructing a three-dimensional comprehensive measurement model.The research work and corresponding achievements of this thesis are as follows:Firstly,to solve the issue of low efficiency of spectrum resource allocation in the network due to crosstalk constraints,the thesis first describes the current state of network in detail by constructing a space-frequency-time three-dimensional crosstalk-fragmentation measurement model.On this basis,a resource allocation algorithm based on a crosstalk classification strategy is proposed to consider crosstalk and fragmentation.According to the state of the network in different periods,the priority of crosstalk and spectrum fragmentation in the resource allocation process is adjusted.The simulation results show that the proposed algorithm can reduce 12% and14% blocking probability and 8% and 10% crosstalk ratio in COST239(Ultra-High Capacity Optical Transmission Networks)and NSFNET(National Science Fund Network),respectively.Secondly,in order to solve the issue of inter-core crosstalk and spectrum fragmentation correlation,based on the three-dimensional comprehensive metric model,this thesis firstly proposes the crosstalk and fragmentation constraint mechanism,which abstracts the crosstalk issue and fragmentation issue into the influence on the spectrum.On this basis,a crosstalk fragmentation constraint algorithm is proposed to constrain the resource allocation process more strictly.Second,to alleviate the problem of low spectrum efficiency caused by strict constraints,blocking probability and crosstalk ratio can be reduced simultaneously by combining with multi-path routing.Simulation shows that the proposed algorithm can reduce about 7% and 9% blocking probability and 9%and 10% crosstalk ratio in the case of COST239 and NSFNET in medium load.