IEEE Communications Magazine • October 2010. 150. 0163-6804/10/$25.00 ...
sponsorship of the IEEE Communications Soci- ety [1]. The resulting IEEE 1901 ...
GOLDFISHER LAYOUT
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ITU STANDARDS
IEEE 1901 Access System: An Overview of Its Uniqueness and Motivation Shmuel Goldfisher, MainNet Communication Shinji Tanabe, Mitsubishi Electric Corporation
ABSTRACT In 2005 the IEEE P1901 Working Group began standardization activities for broadband over power line networks. The process is now in its final stages, and the latest P1901 draft standard is available for sale to the public. The standard is designed to meet both inhome multimedia and utility application requirements including smart grid. The utility requirements and the resulting features that support those requirements were clustered together and form the basis of what is referred to as the utility access cluster. This article explains the aspects of P1901 power line communication technologies designed to address the access cluster. The differences between access and in-home applications, including addressing methods, clock synchronization, smart repetition, quality of service, power saving, and other access unique mechanisms, are also explained.
INTRODUCTION
Disclaimer: The points of view expressed here are solely those of the authors, and in no way is it implied here that these points of view also are shared or supported by the IEEE P1901 work group.
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In June 2005 20 companies agreed to form the IEEE P1901 Working Group (WG) under the sponsorship of the IEEE Communications Society [1]. The resulting IEEE 1901 standard [2] is applicable to both in-home (IH) multimedia and utilities applications. Access networks usually cover large areas, may consist of hundreds or thousands of nodes, and are usually centrally controlled. There are two main types of access applications offered by utilities: broadband applications and utility applications. Typical broadband applications include providing Internet data access and voice over Internet Protocol (VoIP). Typical utility applications include controlling energy use (smart grid) and building/factory controls. Utility applications have been getting a lot of attention recently. For example, the IEEE established a dedicated portal for handling this hot topic [3]. There are two primary approaches for implementing utility applications over the power line network: • A narrowband power line communication (PLC) low-speed approach, for which some solutions are already available
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• A broadband PLC (BPL) approach such as the one developed by the IEEE P1901 Working Group. This article begins by explaining the preference for the broadband PLC approach over a more conventional narrowband PLC approach. Next, we cover the access network’s features and requirements (particularly utility systems) and compare them with those needed for IH systems. We then address some of the design differences in detail such as special addressing methods, clock synchronization, repetition, quality of service (QoS), power saving, and centralized time-division multiple access (TDMA) systems for large topology multihopping access systems.
WHY BROADBAND PLC IS NEEDED FOR LARGE-SCALE ACCESS SYSTEMS The main differences between narrowband (low-speed) and broadband (high-speed) PLC are their bandwidths and the carrier frequencies they use. Figure 1 shows a typical inverter noise spectrum that may be found on the power lines. Narrowband PLC typically uses carrier frequencies below the U.S. amplitude modulated (AM) band (
