Holding-time- and impairment-aware shared spectrum allocation in mixed-line-rate elastic optical networks

Cross-phase modulation (XPM) is considered one of the key factors for the quality-of-transmission (QoT) degradation in elastic optical networks (EONs) with mixed line rates (MLRs). Based on the XPM consideration, this paper proposes a holding-time- and impairment-aware shared spectrum allocation scheme for EONs with MLRs to suppress call blocking in the network. The proposed scheme divides the entire spectrum resources into three exclusive partitioning zones and two shared partitioning zones; furthermore, two exclusive partitioning zones are separated by one shared partitioning zone. A lightpath request is considered as a longer holding-time lightpath request if the holding time of the request is greater than a specified threshold value defined by the network operator; otherwise, the request is considered a shorter holding-time lightpath request. The proposed scheme assigns shorter holding-time lightpath requests to the exclusive partitioning zones and longer holding-time lightpath requests to the shared partitioning zones. It is observed from simulation results that the proposed scheme outperforms the conventional scheme in terms of blocking probability and QoT estimation.