Low power consumption routing and spectrum allocation in optical OFDM networks

We investigated the power consumption of the Bandwidth-Variable Optical Orthogonal Frequency Division Multiplexing (BV-OOFDM) transport networks. OFDM has been recently proposed as a modulation technique for optical networks due to its good spectral efficiency enabling elastic bandwidth transmissions compared with Wavelength Division Multiplexing (WDM). So far, the vast majority of research papers on Routing and Spectrum Allocation (RSA) problem in optical OFDM focus on increasing spectrum efficiency, however power consumption rather than spectral efficiency may eventually become a barrier to the continued growth of the Internet. In this paper, we introduce RSA problem from the viewpoint of network power consumption, which we formulate as Low Power Consumption RSA (LPC-RSA) problem. Different algorithms to solve the LPC-RSA problem are present. We start by presenting an optimal integer linear programming (ILP) RSA algorithm using decomposition method which breaks RSA into its two substituent subproblems, namely, (i) routing and (ii) spectrum allocation and solves them sequentially. For large networks, a heuristic algorithm is also proposed. Our results indicate that RSA with optimal objective of power consumption can have better power consumption and the same spectral efficiency solution compared with RSA with optimal objective of spectral efficiency, and the proposed heuristic algorithm yields close to the optimal solution in low running time.