Priority-Based Inter-Core and Inter-Mode Crosstalk-Avoided Resource Allocation for Spectrally-Spatially Elastic Optical Networks

Spectrally-spatially elastic optical networks (SS-EONs) have been considered nowadays to overcome the physical barrier and enhance the transport capacity, where enhancing spectrum utilization while satisfying inter-core and inter-mode crosstalks is always challenging. This paper proposes a priority-based crosstalk-avoided core, mode and spectrum allocation scheme in SS-EONs, which enhances resource utilization while satisfying both constraints of inter-core crosstalk and inter-mode crosstalk. The proposed scheme creates different groups of cores and modes and assigns a priority to each of them. Core and mode are selected for serving lightpath requests based on their priority order. We define an optimization problem for routing, modulation assignment, spectrum, core, and mode allocation (RA-SCMA) in SS-EONs considering both constraints of inter-core crosstalk and inter-mode crosstalk simultaneously. The optimization problem is formulated as an integer linear programming problem. We prove that the decision version of RA-SCMA is NP-complete. We present crosstalk-avoided core-mode-spectrum allocation considering a dynamic scenario. Numerical results indicate that the proposed scheme reduces the blocking probability in SS-EONs and allows up to 40% increased traffic loads by utilizing the crosstalk-avoided unutilized slots compared to the conventional scheme that adopts a core-mode-spectrum first fit policy.