Analysis of on-line routing and spectrum allocation in spectrum-sliced optical networks

The orthogonal frequency division multiplexing (OFDM) technology provides an opportunity for efficient resource utilization in optical networks. It allows allocation of multiple sub-carriers to meet traffic demands of varying size. Utilizing OFDM technology, a spectrum efficient and scalable optical transport network called SLICE was proposed recently. The SLICE architecture enables sub-wavelength, super-wavelength resource allocation and multiple rate data traffic that results in efficient use of spectrum. However, the benefit is accompanied by additional complexities in resource allocation. In SLICE architecture, in order to minimize utilized spectrum, one has to solve the routing and spectrum allocation (RSA) problem, a generalization of the routing and wavelength allocation (RWA) problem. In this paper, we focus our attention to the on-line version of RSA problem and provide an algorithm for the ring network with a competitive ratio of min{O(log(d_max)), O(log(k))} where k is the total number of requests and d_max is the maximum demand in terms of the number of sub-carriers. Moreover, we provide a heuristic for the network with arbitrary topology and measure the effectiveness of the heuristic with extensive simulation.