A Survey on OFDM-Based Elastic Core Optical Networking <s> 6) Energy Efficiency <s> Nowadays, energy related problems are becoming a key environmental, social and political issue because the demand for energy and power resources grows continuously. A decoupling of economic growth and energy consumption becomes a very important goal that can be achieved only by increasing the energy efficiency of new technologies and processes, i.e., the ability to provide a higher performance by consuming less energy. Communication networks play a significant role as the crucial part of the information and communication technologies. An adequate and future-ready communication network infrastructure has become one of the most important strategic goals of any government, region, and municipality, because a high-capacity and efficient network leads to an accelerated development of both business and society. This paper aims to give an overview on possible potentials of new technologies for implementing energy-efficient network elements. It identifies main energy-related issues in high-performance network elements and tries to draw attention to some promising approaches for implementing low-consuming components and networks. Various aspects related to applications and services that can make use of the energy-efficient and high-performance global networks are discussed. Some thoughts about possible implications on energy productivity, economy, and society can also be found. <s> BIB001 </s> A Survey on OFDM-Based Elastic Core Optical Networking <s> 6) Energy Efficiency <s> The sustained growth of data traffic volume calls for an introduction of an efficient and scalable transport platform for links of 100 Gb/s and beyond in the future optical network. In this article, after briefly reviewing the existing major technology options, we propose a novel, spectrum- efficient, and scalable optical transport network architecture called SLICE. The SLICE architecture enables sub-wavelength, superwavelength, and multiple-rate data traffic accommodation in a highly spectrum-efficient manner, thereby providing a fractional bandwidth service. Dynamic bandwidth variation of elastic optical paths provides network operators with new business opportunities offering cost-effective and highly available connectivity services through time-dependent bandwidth sharing, energy-efficient network operation, and highly survivable restoration with bandwidth squeezing. We also discuss an optical orthogonal frequency-division multiplexing-based flexible-rate transponder and a bandwidth-variable wavelength cross-connect as the enabling technologies of SLICE concept. Finally, we present the performance evaluation and technical challenges that arise in this new network architecture. <s> BIB002
Energy consumption and efficiency are becoming major concerns for network operators, as it is of significant importance to build communication networks that enables future energy savings to relax the issues related to the climate change, as well as to scale network architectures supporting rapid growth of traffic demands BIB001 . The elastic nature of an OFDM-based network provides efficient packing of user traffic demands, and ensures high resource utilization on each OFDM link. This helps to reduce the energy consumption in the network, as less transponders and amplifiers are used compared with a traditional WDM network. Moreover, in a dynamic traffic scenario where the network load is changing with time, the capacity of an elastic optical path supporting the traffic can change dynamically according to the load, by adjusting the number of subcarriers. Therefore, the data-rate/bandwidth variable transponder can support energy-efficient operations by turning on/off different subcarriers, and adapting its energy consumption according to the amount of traffic to be transported. Also, the optical pump power of the optical amplifiers on the route could be increased or reduced to the appropriate level for supporting the client traffic. These operations will reduce the overall energy consumption of the network BIB002 . Numerical studies on the energy efficiency of an OFDMbased elastic optical network are expected, and more research work is needed on the design of bit-rate/bandwidth-variable transponders and RSA schemes to support the energy-efficient operations.