A Research on Spectrum Defragmentation Algorithms in Elastic Optical Network

With the rapid development of mobile communication technology and the increasing requirements of mobile data services, elastic optical network (EON) which has better resource utilization and more flexible spectrum allocation is widely investigated. EON could support a transmission rate from Gbps to Tbps. It could also adjust modulation format according to different transmission distance so that it could make better utilization of spectrum resources. Owing to flexible grid, spectrum allocation should satisfy the criteria of spectrum consistency and spectrum continuity, which would lead to spectrum fragmentation and decrease the network performance. In this paper, the spectrum fragmentation problem in EON is investigated. Firstly, the reason of spectrum fragmentation problem is introduced. Then different Spectrum defragmentation algorithms are analyzed and compared in detail. Finally, the future development of spectrum defragmentation methods is prospected.