Abstract-Orthogonalfrequency-division multiplexing (OFDM) is a modulation technology that has been widely adopted in many new and emerging broadband wireless and wireline communication systems. Due to its capability to transmit a high-speed data stream using multiple spectral-overlapped lower-speed subcarriers, OFDM technology offers superior advantages of high spectrum efficiency, robustness against inter-carrier and inter-symbol interference, adaptability to server channel conditions, etc. In recent years, there have been intensive studies on optical OFDM (O-OFDM) transmission technologies, and it is considered a promising technology for future ultra-high-speed optical transmission. Based on O-OFDM technology, a novel elastic optical network architecture with immense flexibility and scalability in spectrum allocation and data rate accommodation could be built to support diverse services and the rapid growth of Internet traffic in the future. In this paper, we present a comprehensive survey on OFDM-based elastic optical network technologies, including basic principles of OFDM, O-OFDM technologies, the architectures of OFDMbased elastic core optical networks, and related key enabling technologies. The main advantages and issues of OFDM-based elastic core optical networks that are under research are also discussed.

No abstract

No abstract

No abstract

We examine how datarate-adaptive transceivers can be used to follow the pronounced variations in requested bandwidth in core networks and therefore allow significant energy savings compared to static networks configured to support the peak traffic all the times. We investigate two schemes for datarate adaptation in optical transceivers: modulation-format adaptation and symbol-rate adaptation, and show how they yield comparable energy savings but through very different mechanisms. We quantify these energy savings with respect to static networks for the case of a European backbone network and find potential for up to 30% of savings when the two schemes are combined.