Crosstalk-Aware Spectrum Defragmentation Based on Spectrum Compactness in Space Division Multiplexing Enabled Elastic Optical Networks With Multicore Fiber

Achievable capacity of optical fiber is approaching its physical limitation in frequency domain. Space division multiplexing (SDM) technology can scale the network capacity using multi-core fiber and multi-mode fiber. In order to provide high-speed transmission services with fine granularities, SDM enabled elastic optical networks (SDM-EONs) become a promising candidate of future optical transport networks. However, since the spectrum status in SDM-EONs becomes more complex with the introduction of spatial dimension, the issue of spectrum fragmentation will be more serious in SDM-EONs compared in simple EONs. To remedy the issue of spectrum fragmentation in SDM-EONs, we propose a crosstalk-aware spectrum defragmentation (CASD) algorithm based on a metric, i.e., spectrum compactness (SC), which we define to measure the spectrum status in the SDM-EONs. Simulation results show that the proposed CASD algorithm can achieve better performance than a benchmark algorithm in terms of blocking probability and spectrum utilization. We also compare CASD algorithm with different SC thresholds in bandwidth blocking probability and spectrum utilization. Among them, CASD algorithm with SC threshold of 50 performs the best. It can achieve low spectrum moving times as well as low defragmentation latency.