Ever-increasing bandwidth demands associated with mobile backhaul, content-rich services and the convergence of residential and business access will drive the need for next-generation passive optical networks (NG-PONs) in the long term. At the same time, there is a growing interest in reducing the energy consumption and the associated cost of the access network. In this paper, we consider a deployment scenario in a major city to assess the energy efficiency of various PON solutions from a telecom operator's perspective. We compare five nextgeneration technologies to a baseline GPON deployment offering similar bandwidths and Quality of Service (QoS) for best-effort high speed connectivity services. We follow two approaches: first, we consider a fixed split ratio (1:64) in an existing Optical Distribution Network (ODN); next, we consider an upgraded ODN with an optimized split ratio for the specific bandwidth and QoS values.For medium bandwidth demands, our results show that legacy PONs can be upgraded to 10G PON without any ODN modification. For future applications that may require access rates up to 1 Gb/s, NG-PON2 technologies with higher split ratios and increased reach become more interesting systems, offering the potential for both increased energy efficiency and node consolidation. Keywords: energy consumption, next-generation passive optical networks, split ratio
INTRODUCTIONFiber-based gigabit passive optical networks (G/E PONs) are currently being deployed by operators in several countries, offering much higher bandwidths than traditional copper-based access networks. Deployments of 10 Gb/s capable PONs (XG-PON1) are expected in the next couple of years. In the long term, exponential bandwidth demand growth due to the rise of new video services (such as ultra High Definition and 3D formats) in all flavors (VoD, Peer to Peer) and the potential convergence of wireless and wireline access will necessitate the deployment of even faster next-generation PONs beyond 10 Gb/s, referred to as NG-PON2s [1]. Due to rising energy prices and the growing awareness of climate change, energy efficiency will be an important factor to take into consideration when analyzing the operational expenditures and carbon footprint of the different NG-PON2 technologies [1]. In this paper, we assess the energy efficiency of G/E PON, 10G PON and four NG-PON2 candidates. Our analysis focuses on the power consumption at the Central Offices (COs) of the network provider. For a general analysis of power saving strategies in home networks and in a PON Optical Network Unit (ONU), we refer to [2], where energy efficiency improvement options in hardware design and virtualization are discussed.In this work, we analyze how energy efficiency at the CO is affected by the chosen network deployment and by user demand. We consider a deployment scenario in a major European city to get a more realistic estimation than a purely component-based analysis, taking into account the implications of technology-dependent physical reach over a target ar...