Signal transmission using counter-propagation nowadays is adopted to enhance resource utilization in spectrally-spatially elastic optical networks (SS-EONs), where inter-mode and inter-core crosstalks always degrade signal quality and become bottlenecks for high transport capacity. In this paper, we propose BPRIA for the first time, a Bi-Partitioning-based crosstalk-avoided Resource Identification and Allocation scheme in SS-EONs to enhance resource utilization while suppressing both inter-mode and inter-core crosstalks. We introduce a bi-partitioning optimization problem with vertex elimination to maximize the number of non-adjacent cores and modes in each partition of the bipartite graph; two distinct sets of cores and modes are used in a counter-propagation manner for lightpath allocation. The optimization problem is formulated as an integer linear programming (ILP) problem, and we prove that the optimization problem is NP-complete. An algorithm for core-mode-spectrum allocation is developed considering two distinct sets of cores and modes obtained by ILP to serve lightpath requests while avoiding inter-mode and inter-core crosstalks. For dynamic scenarios, we present core-mode-spectrum allocation. Numerical results reveal that the blocking probability is reduced by BPRIA in SS-EONs, and it enhances traffic admissibility in the network.

Fragmentation with crosstalks is the major obstacle in spectrally-spatially elastic optical networks, which suppresses resource utilization while degrading the quality-of-transmission. To overcome this issue, this article proposes, for the first time, a proactive fragmentation management scheme based on batch processing while satisfying both inter-core and inter-mode crosstalks to enhance resource utilization. The proposed scheme adopts a batch processing method to create batches of lightpath requests received within a time threshold to utilize spectrum resources effectively. In batch processing, lightpath requests are prioritized based on the number of links in their routes and required slots. To maintain fairness in batch processing, when any request is rejected, the proposed scheme triggers a procedure that gives an equal opportunity to all arriving requests within the threshold, irrespective of numbers of hops and requested capacities, for allocation. We formulate the static batch processing of lightpath requests (SBPLR) as an integer linear programming (ILP) problem. We prove that SBPLR is an NP-Complete problem. We introduce a heuristic solution when ILP is intractable. To serve lightpath requests in each batch while avoiding inter-core and inter-mode crosstalks, we develop a core-mode-spectrum allocation algorithm. We present a dynamic batch processing based fragmentation management approach. Numerical results indicate that the proposed scheme outperforms the benchmark schemes.

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.