Penalty-Method Based Impairment-Aware Performance Of Elastic Optical Networks With Spectrum Conversion

In Elastic Optical Networks (EONs), fragmentation is a major bottleneck which affects the spectral efficiency significantly. Many defragmentation techniques have been proposed to tackle this issue and often, these schemes involve complex operations at the controllers and various sophisticated devices. Moreover, the amount of defragmentation achieved is also limited. In this regard, recently, spectrum conversion is gaining attention as a potential solution for the fragmentation issue in EONs. On the other hand, physical-layer impairments such as non-linear interference, amplified spontaneous emission (ASE) noise, beat noises due to coherent detection, etc. aggravate the fragmentation issue significantly. In this paper, we propose a novel impairment-aware routing and spectrum allocation (RSA) scheme with allowable spectrum conversion at intermediate nodes. We also propose a novel node architecture involving spectrum conversion with full switching flexibility. We first formulate a mixed integer linear program (MILP) optimization framework based on the proposed architecture in presence of impairments for a sample network and propose a penalty-method-based heuristic algorithm for realistic networks. Within our optimization framework, we ensure that a minimum end-to-end bit error rate (BER) for each demand is provisioned.