An optimization framework for energy-efficient elastic optical transmission systems

The use of Orthogonal Frequency Division Multiplexing (OFDM) technology helps an optical transmission system to break the limitation of wavelength grids by Wavelength Division Multiplexing (WDM), in which a flexible and elastic transmission paradigm is created, so as to achieve better spectrum efficiency and flexibility of the fiber resources. This paper investigates a novel adaptive transmission strategy in OFDM based optical transmission systems, aiming to minimize the transmission cost for a bulk data transfer request in terms of energy consumption and bandwidth usage without violating the constraints on the transmission delay and bit error rate (BER) at the receiver. By considering nonlinear effects of Mach-Zehnder modulator (MZM) and amplified spontaneous emission (ASE) noise from optical amplifier, a novel analytical model for the BER expression is provided and the corresponding optimization problem is formulated. In particular, the proposed formulation is the first in the literature that considers the effect of Peak-to-Average Power Ratio (PAPR) on both electrical and optical domain signals. By adaptively choosing the number of subcarriers, modulation level, and coupled laser power, the transmission cost for a given request can be minimized.