Adaptive Elastic Spectrum Allocation Based on Traffic Fluctuation Estimate in Flexible OFDM-based Optical Networks

A flexible orthogonal frequency-division multiplexing optical network enables to change bandwidth flexibly by changing the number of sub-carriers. We consider that users request to dynamically change the number of sub-carriers. In this context, the network resources can be used more efficiently. The dynamic bandwidth change needs a certain time. Service centric resource allocation must be considered in terms of waiting time to change the number of sub-carriers. If the user demands drastically increase such as a disaster priority telephone service, a waiting time for bandwidth changes is not tolerated because emergency is time-critical. This is caused by a chain-change of bandwidth such as a multiple-car pileup. This paper proposes a grouped elastic spectrum allocation scheme to satisfy the tolerable waiting time of the service in an optical fiber link. Spectrums are grouped to restrict a waiting time in the proposed scheme. In addition, the proposed scheme determines a margin bandwidth with neighbor spectrums to prevent frequent reallocation by estimating real traffic behavior. Numerical results show that a required bandwidth can be saved with satisfying waiting time constraints. Additionally measurement granularity is discussed.