Research On Fragment And Crosstalk Awared Resource Allocation In Space Division Multiplexing Elastic Optical Network(SDM-EON)

The elastic optical network adopts the orthogonal frequency division multiplexing technology to further divide the network spectrum resources into spectrum units with smaller granularity.The spectrum resources can be dynamically and effectively allocated according to the actual service requirements,so as to improve the utilization rate of network resources and service the purpose of transmission efficiency.The space division multiplexing technology can double the transmission capacity of the optical fiber by directly expanding the optical fiber in the spatial dimension.By combining the elastic optical network and the space division multiplexing technology,the space division multiplexing elastic optical network(SDM-EON)technology has become the best solution to transmit large-capacity data in the optical fiber and efficiently respond to dynamic business needs.Through theoretical comparison and modeling and simulation methods,this paper conducts a comprehensive and in-depth study on routing core and spectrum allocation,and spectrum fragmentation avoidance in spatial division multiplexing elastic optical networks.This paper first briefly describes the basic concepts,infrastructure,routing core and spectrum allocation(RCSA)issues,and key technologies such as inter-core crosstalk of SDM-EON.Aiming at the problem of spectrum allocation in SDM-EON,this paper proposes a load-balanced fragmentationaware RMCSA algorithm based on frequency spectrum allocation pattern.The core idea of this algorithm is to use a new load balancing algorithm in the routing and modulation allocation(RMA)stages.Different from common load balancing algorithms,the improved algorithm not only considers the length of the link,but also considers the spectrum occupancy status of the link in the weight of the link.In the phase of core and spectrum allocation(CSA),a new frequency slot allocation mode is introduced.Its core idea is to use super channel technology to support the same service request during spectrum allocation under the premise of suppressing inter-core crosstalk,that is,to allocate frequency slots to different cores.And for each frequency slot allocation mode,an evaluation method for the cost of CSA candidates is proposed,so as to evaluate the pros and cons of each CSA candidate.Theoretical analysis and simulation results show that compared with the AW-PF algorithm,the FALBR algorithm can achieve lower blocking rate and higher network resource utilization performance in CERNET,USNET and JPN networks.Aiming at the problem of spectrum fragmentation caused by the operation of the elastic optical network through space division multiplexing,the paper proposes the concept of time and space fragmentation metric(TSFM),and measures the degree of spectrum fragmentation of the link according to the size of the TSFM value.Different from the traditional spectrum fragmentation assessment scheme that only considers the current fragmentation situation on the link,the core idea of TSFM is to better and more accurately evaluate the fragmentation degree from the three dimensions of time dimension,space dimension and single fragment.Based on this,a time and space fragmentation crosstalk-aware RCSA algorithm is proposed in this paper.Theoretical analysis and simulation results show that compared with the RF-CA algorithm,the blocking rate and spectrum utilization performance in CERNET,USNET and JPN can be effectively improved.