Modeling and analysis of crosstalk-avoided and crosstalk-aware approaches in spectrally-spatially elastic optical networks

Abstract

Inter-core crosstalk (Ic-Xt) and inter-mode crosstalk (Im-Xt) occur during the transmission of optical signals through multi-core multi-mode fibers in spectrally-spatially elastic optical networks (SS-EONs), which degrade the signal quality. Xt-Avoided (Xt-Av) and Xt-Aware (Xt-Aw) approaches, respectively, are used in SS-EONs for dealing with Ic-Xt and Im-Xt. From the network deployment perspective, network operators need to understand which approach, Xt-Av or Xt-Aw, is better in order to deal with Ic-Xt and Im-Xt in SS-EONs. To address the above issue, this paper models and analyzes Xt-Av and Xt-Aw approaches by considering Ic-Xt and Im-Xt simultaneously in SS-EONs. We formulate the optimization problems as the integer linear programming (ILP) problem for both Xt-Av and Xt-Aw approaches. When the ILP problems are intractable, we introduce heuristics for Xt-Av and Xt-Aw approaches. We compare ILP and heuristic approaches using Xt-Av and Xt-Aw in terms of the maximum allocated spectrum slot index, blocking ratio, and computation time. Numerical results indicate that the Xt-Aw approach for all Xt threshold values performs better than the Xt-Av approach in terms of resource utilization. At the same time, the Xt-Av approach has the advantage of using less computation time than the Xt-Aw approach. The analysis reveals that, in the Xt-Aw approach, the behavior of the maximum allocated spectrum slot index and blocking ratio on Xt threshold is reciprocal, and hence a suitable Xt threshold that enhances the network performances is required for network management.