Energy-efficient impairment-constrained 3R regenerator placement in optical networks

In this paper, we study the energy-efficient impairment-constrained regenerator placement (EIRP) problem with the objective of minimizing the total energy consumption in optical networks with mixed line rates. The destination of each path is guaranteed to receive the data correctly from the source based on the regenerator placement. We first provide the problem definition of EIRP and show that the EIRP problem is NP-complete. We then formulate the problem as a mixed integer linear program (MILP) and give results for small scale problems. Two heuristic approaches, named high line rate first (HLRF) and reroute only (RO), are presented. Numerical results show that HLRF achieves good results in both large and small scale problems, and that HLRF achieves higher energy efficiency than RO.