High Speed Power Line Communication Technology

1 ISSN 1345-3041. Mar. 2005 High Speed Power line Communication Technology ADVANCE. Mar. 2005 / Vol. 109. MITSUBISHI ELECTRIC. High Speed Power line Communication Technology Cover Story CONTENTS. The access-type PLC network system is designed to form an access network by using already-existing MV Technical Reports and LV Power lines, and provides end-users with Internet-access and VoIP services. The PLC access-type network system consists of MV. by Akira Horiguchi (medium-voltage) nodes that are equipped with an interface with a backbone optical network, CPE. (Customer Premises Equipment), and REPs (repeaters) Perspective on Power line Communication .

2 2. that relay signals between MV nodes and CPE. by Tadashi Matsuzaki and Shinji Tanabe The figure shows MV (medium-voltage) nodes REP, and CPE. The user can have high- Speed Internet access World Trends in Power line Communication ..5. or use high- Speed digital services such as image downloading and video streaming by connecting a by Yoshinori Mizugai and Masahiro Oya personal computer to an Ethernet or a USB interface of the CPE, and thus accessing his/her ISP (Internet High Speed PLC for Access Network service provider). At the same time, VoIP service can be by Sawako Ojima and Yasuaki Hori subscribed to by connecting an analog telephone set to the CPE's telephone interface.

3 PLC Network Management by Toshinobu Akitomi and Takeo Kikuchi Editorial-Chief Yoshikazu Mishima Power System Technology for Power line Communication System ..15. Editorial Advisors by Tetsuro Shimomura and Hiromu Okamoto Chisato Kobayashi Koji Kuwahara Inductive Coupling Unit and Bypass Tool for Power line Keizo Hama Kazuo Seo by Yuichiro Murata and Toru Kimura Yukio Kurohata Hiroshi Hasegawa Hiroshi Muramatsu Masato Fujiwara R&D P. Report Fuminobu Hidani Hiroshi Yamaki An Introduction to the Low-Density Parity-Check ..21. Kiyohide Tsutsumi by Wataru Matsumoto Osamu Matsumoto Hiromasa Nakagawa Vol. 109 Feature Articles Editor Technical Highlight Tetsuro Shimomura Distribution Network Analysis and Service Provisioning Editorial Inquiries Support Keizo Hama by Masashi Kitayama and Junichi Abe Corporate Total Productivity Management & Environmental Programs Fax 03-3218-2465.

4 Product Inquiries PLC Marketing Section Information & Communication Marketing Dept. Power Systems Marketing Division MITSUBISHI ELECTRIC CORPORATION. FAX 03-3218-2761. Mitsubishi Electric Advance is published on line quarterly (in March, June, September, and December) by Mitsubishi Electric Corporation. Copyright 2005 by Mitsubishi Electric Corporation; all rights reserved. Printed in Japan. TECHNICAL REPORTS. Overview Author: Akira Horiguchi*. The widespread use of broadband Communication , has been encaged worldwide as a basic infrastructure of information Communication for society. Several Communication means are available e. g. cable television (CATV), ADSL or high- Speed PLC.

5 Some countries have few fixed telephone lines, while in others CATV is rare. Therefore, ADSL or CATV alone cannot support the proliferation of broadband access. In contrast, high- Speed PLC Technology uses existing Power lines for Communication and so obviates the need for stringing new Communication cables and is a viable means of increasing broadband access. Communication using Power lines has a long history; indeed, the idea has been around since the beginning of the twentieth century. In the 1980s, very low- Speed PLC systems were used for controlling electronic equipment such as light dimmers. However, since the characteristics for Power lines to serve as a communications means have not been defined and because the characteristics of Power lines will change when Power equipment and household electrical appliances are connected to them, PLC systems are still not widely used.

6 In spite of such problems, high- Speed PLC is becoming economically viable due to advances in analog circuit Technology , digital signal-processing Technology , and large-scale integration (LSI) Technology . In recent years, PLC. systems operating at up to 200 Mbps have been announced, and R&D is currently underway to increase the Speed further. In the future IT society, network access will be available anywhere and to everyone. It is firmly believed that high- Speed PLC will contribute toward achieving such objective. *Public-Use e-solution Center Mitsubishi Electric ADVANCE March 2005 1. TECHNICAL REPORTS. Perspective on Power line Communication Authors: Tadashi Matsuzaki* and Shinji Tanabe**.

7 Power line Communication (PLC) is a type of which is also adopted by cellular phones and similar Communication using Power line in which modulated equipment for CDMA (Code Division Multiple Access), radio-frequency signals are transmitted. Thanks to and OFDM (Orthogonal Frequency Division Multiplex- recent advances in digital communications Technology , ing) which is also used by ADSL and digital broadcast- it is becoming possible to achieve communications ing. In the case of high Speed PLC, many chipmakers speeds in excess of 100 Mbps. The potential imple- are adopting OFDM. OFDM is a method whereby each mentation of PLC, with the main focus on Internet ac- carrier is placed in such a manner that its bandwidth cess, is being studied in various European and Asian overlaps those of adjacent carriers by exploiting or- countries as well as in the United States, and huge thogonality.

8 Since this method permits the use of a few markets have begun forming. hundred to a few thousand carriers simultaneously within a limited bandwidth, its frequency utilization 1. Power line Network efficiency is very high and transfer rates ranging from Power lines assume a wide variety of network to- several tens to several hundreds of Mbps are possible. pologies because their length, number of branches, Furthermore, flexible bandwidth utilization is also possi- Power line equipment such as connected capacitor ble, for example, through changing the number of bits bank are vary from area to area, country to country. to be allotted to each individual carrier, depending on They were not originally intended for use of data net- the condition of transmission paths and avoiding par- working as broadband media, thus no particular re- ticular carriers on a selective basis to ensure peaceful quirements were not considered.

9 As for materials of coexistence with pre-existing communications bands. electric wire there are differences between those used An overview of OFDM Technology is shown in Fig. 1. for distribution lines and in home line respectively, as Transmission loss well as differences among countries. Compounding the Narrow-band noise characteristics problems, in many cases, noise is produced by equip- ment connected to Power line , meaning the sig- nal-transmission characteristics of Power lines for ra- dio-frequency vary according to location, as well as time. When the characteristics of Power lines are seen from the perspective of communications on a fre- MHz or more Bit allocation 30 MHz or less quency-band basis, Bands below 2 MHz present ad- Bands not in use adjustment verse conditions due to reasons of high noise and low A large number of communications carriers (1,000 or more) are accommodated in available frequency bands.

10 High- Speed communications are carried out in an impedance and difficult to achieve high Speed commu- adaptive manner in accordance with noise and loss characteristics. nication. On the other hand, the 2-to-30-MHz range is, Fig. 1 OFDM Technology with a relatively low level of noise, and possible to use as a broadband media, even though signal transmis- In addition, as an important Technology for use on sions suffer losses in this range. the physical layer, there is coupling circuitry with which to inject/extract signals to/from Power lines. In the case 2. PLC Communications Technology of Power distribution and branch lines, Technology Generally speaking, communications functionality exists enabling the installation of PLC modems without is defined using a layered model.