Abstract:
Predeployment of regenerators in a selected
subset of network nodes allows service providers to
achieve rapid provisioning of traffic demands, high utilization,
and reduced network operational costs, while still
guaranteeing lightpath quality of transmission. Enabled
by bandwidth-variable transceivers in flexible-grid optical
networks, optical channel bandwidths are no longer fixed
but constantly changing according to real-time communication
requirements. Consequently, the data-rate-variable
traffic together with other new network features introduced
by flexible-grid networks will render the regenerator
allocation very difficult due to the complicated network
states. In this paper, we investigate how to allocate regenerators
robustly in flexible-grid optical networks to combat
physical-layer impairments when the data rates of traffic
demands are random variables. The Gaussian noise model
and a modified statistical network assessment process
framework are used to characterize the probabilistic distributions
of physical-layer impairments for each demand,
based on which a heuristic algorithm is proposed to select
a set of regenerator sites with minimum blocking probabilities.
Our method achieves the same blocking probabilities
with on average 10% less regenerator sites compared with
the greedy constrained-routing regenerator allocation
method, and obtains blocking probabilities two orders of
magnitude lower than that of the routing and reach method
with the same number of regenerator sites.
