Routing and Spectrum Allocation in Spectrum-sliced Elastic Optical Path Networks

The Spectrum-sliced Elastic Optical Path (SLICE) networks adopt the Orthogonal Frequency Division Multiplexing (OFDM) technology to offer flexible and elastic band-width allocation. The OFDM technology enables both sub-wavelength and super-wavelength traffic accommodation by allocating appropriate number of sub-carriers while providing high signal quality and mitigating various impairments. To accommodate traffic demands in SLICE networks, one fundamental problem is to establish spectrum paths by allocating sub-carriers along the corresponding routes, which is referred to as the routing and spectrum allocation (RSA) problem. The optimal RSA problem is NP-Hard and different from the traditional routing and wavelength assignment (RWA) problem in WDM networks. In this work, we model the RSA problem using a set of proposed Integer Linear Programming (ILP) formulations to achieve different optimization objectives. We also present new approaches to analyze the lower/upper bounds for the sub-carrier number in a SLICE network. Two efficient heuristic algorithms are also studied in our simulation under different optimization goals.