Quality of transmission estimation in WDM and elastic optical networks accounting for space-spectrum dependencies

I. Sartzetakis, K. Christodoulopoulos, C.P. Tsekrekos, D. Syvridis, E. Varvarigos

Research output: Contribution to journalArticlepeer-review


We develop a framework for estimating the quality of transmission (QoT) of a new lightpath before it is established, as well as for calculating the expected degradation it will cause to existing lightpaths. The framework correlates the QoT metrics of established lightpaths, which are readily available from coherent optical receivers that can be extended to serve as optical performance monitors. Past similar studies used only space (routing) information and thus neglected spectrum, while they focused on oldgeneration noncoherent networks. The proposed framework accounts for correlation in both the space and spectrum domains and can be applied to both fixed-grid wavelength division multiplexing (WDM) and elastic optical networks. It is based on a graph transformation that exposes and models the interference between spectrum-neighboring channels. Our results indicate that our QoT estimates are very close to the actual performance data, that is, to having perfect knowledge of the physical layer. The proposed estimation framework is shown to provide up to 4 × 10-2 lower pre-forward error correction bit error ratio (BER) compared to theworst-case interference scenario,which overestimates the BER. The higher accuracy can be harvested when lightpaths are provisioned with low margins; our results showed up to 47% reduction in required regenerators, a substantial savings in equipment cost.

Original languageEnglish
Pages (from-to)676-688
Number of pages13
JournalJournal of Optical Communications and Networking
Issue number9
Early online date23 Aug 2016
Publication statusPublished - 1 Sept 2016


  • correlation
  • fixed grid and elastic optical networks
  • interference
  • network kriging
  • physical layer impairments
  • quality of transmission (QoT) estimation


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