Crosstalk-aware Optimal Design For Multi-core Fiber Elastic Optical Networks

With the rapid development of Internet,high-bandwidth services such as big data,cloud computing,and video on demand are becoming more and more popular,which leads to explosive growth of Internet traffic.Traditional standard single-mode fiber(SSMF)-based wavelength division multiplexing(WDM)transmission systems approach its nonlinear Shannon capacity limit,and are unable to meet the demand of rapidly growing network services.To rapidly increase the capacity of optical networks,researchers have conducted extensive studies in two dimensions.In the first dimension,elastic optical networks(EON)with finer grid granularity and more flexible spectrum allocation were studied to enhance spectrum resource utilization.In the second dimension,space division multiplexing(SDM)technology,which transmits multiple independent optical signals in parallel in spatial channels,can increase the capacity of a transmission system several times compared to the traditional SSMF system.Among multiple SDM technologies,multi-core fiber(MCF)based SDM technology is considered most promising.Thus,by integrating the above two dimensions,multi-core fiber elastic optical network(MCF-EON)is considered the most promising architecture for enhancing optical network capacity.For MCF-EON,there have been many studies focusing on network resource optimization.However,few studies consider inter-core crosstalk of MCF,which can directly affect the establishment of lightpaths and their transmission capacities.Therefore,it is important to consider optimizing the inter-core crosstalk of MCF when allocating network resources.In this thesis,we focus on inter-core crosstalk-aware network optimization for MCF-EON,and the main research contents and novelties are as follows.(1)A more generalized inter-core crosstalk calculation model is considered.In existing studies,the model for inter-core crosstalk calculation only considers crosstalk between adjacent cores,and assumes equal distances between all adjacent cores.Actually,the intercore crosstalk also occurs between non-adjacent cores,even though they are much smaller.Moreover,in MCFs with different core layouts,the distances between different cores are also different.All these factors will lead to a large error in the traditional inter-core crosstalk calculation method.In view of this,this study will consider a more accurate inter-core crosstalk calculation model,which can be applied to MCFs with different types of core layout,and can also accurately calculate the inter-core crosstalk between non-adjacent cores.(2)MCF-EON optimal design based on signal counter-propagation in MCF cores.Recent studies demonstrated that signal counter-propagation in MCF cores can effectively reduce inter-core crosstalk.Considering this and noting increasing asymmetric bi-directional traffic demand,this study for the first time applies signal counter-propagation in MCF cores to MCF-EON and develops a crosstalk-aware network optimization scheme.For the routing,core and spectrum allocation(RSCA)problem in the context of bi-directionally asymmetric traffic demand in MCF-EON,an integer linear programming(ILP)optimization model is formulated and an efficient auxiliary-graph-based algorithm is developed.Simulation results show that the crosstalk-aware signal counter-propagation strategy can not only effectively reduce inter-core crosstalk,but also significantly improve network resource utilization.In addition,the proposed heuristic algorithm can achieve performance very close to the ILP optimization model,which confirms the efficiency of the proposed heuristic algorithm.(3)MCF-EON optimal design for scheduled lightpath demands.Most existing works on MCF-EON focused on static or dynamic lightpath demands.However,in the actual network scenario,scheduled lightpath demands,which have pre-determined earliest setup times,latest release times,and service durations,are also popular.Jointly considering the spatial,frequency,and time dimensions,this study looks into the routing,core,spectrum,and time allocation(RCSTA)problem for scheduled lightpath demands in MCF-EON.The RCSTA problem is formulated as an ILP optimization model,and an efficient auxiliarygraph-based algorithm is proposed to efficiently allocate network resources.Simulation results show that the proposed crosstalk-aware RCSTA scheme can effectively reduce the inter-core crosstalk while optimizing network resources,and the auxiliary-graph-based algorithm can perform very close to the ILP optimization model.(4)Optimal network design for SBPP-based MCF-EON.Because an MCF carries much more traffic demand than a traditional SSMF,network protection is even more important for MCF-EON.Among many network protection techniques,shared backup protection(SBPP)is considered one of the most promising techniques.In this study,to jointly optimize the inter-core crosstalk and network resources in an SBPP-based MCF-EON,an ILP optimization model is formulated and an efficient heuristic algorithm is proposed for the crosstalk-aware routing,spectrum,and core assignment(CA-RCSA)problem.Simulation results show that the proposed CA-RCSA scheme can effectively improve network resource utilization while reducing inter-core crosstalk.