Vol. 17, No. 2; May 2004

New Developments with PLC in Japan

The Japan Amateur Radio League (JARL) is cautiously watching new developments concerning the commercialization of Power Line Communications (PLC), while continuing to carry out joint experiments with a high speed power line communication promoters' alliance to reduce potential interference to radio communications.

PLC is known as broadband over power line (BPL) in some parts of the world. The Japanese Ministry of Public Management, Home Affairs, Posts and Telecommunications (MPHPT) two years ago inaugurated the Power Line Communications Study Group. JARL became a member of its working group of field tests and took part in various demonstration tests. Among the members of the working group were NHK (Japan Broadcasting Corporation) and a sub-committee on Radio Astronomy Frequencies, as these organizations' activities are deeply related to HF bands. The Ministry's Study Group announced the following conclusion in August 2002:

"In the light of modems under development and the current situation over power lines, it is likely that power line communications equipment will become a source of harmful interference with radio communications including air traffic control and short-wave broadcasting, making it difficult to expand frequency ranges for use. In view of possible future development of technology designed to reduce leaked electric field strength in modems for PLC and power lines, it is necessary to continue research and development. Therefore, a system should be established to permit the construction and use of equipment for research and development, or demonstration tests."

Please refer to JARL News of August 2002:

On the basis of the above conclusion, "a system to permit the construction and use of equipment for research and development, or demonstration tests" MPHPT announced the overview of an experimental system for PLC in January 2004 as follows:

(1) Conditions for permission of PLC equipment for experiments. Equipment can be used to corroborate technology designed to reduce electromagnetic radiation leakage from power lines. The frequency range should be between 2 MHz and 30 MHz.

(2) Measures to prevent interference. Those entities planning to install experimental equipment should set targets for electromagnetic radiation leakage from power lines and provide technical reasoning that interference can be prevented. They should notify neighboring residents of experiment plans in advance. If interference occurs, they must suspend experiments immediately and find the causes, and must not resume experiments until they confirm that interference will never occur.

(3) Announcement of experiments Those entities planning to conduct experiments should release their names and contact address, place of installation and frequency ranges for use on the homepage of the Ministry of Public Management, Home Affairs, Posts and Telecommunications.

In a press release dated March 10, 2004 headlined "Kyushu Electric Power Co. given the green light for high-speed power line carrier communications equipment, the first in Japan," the Kyushu Regional Bureau of Telecommunications announced that it gave experimental permission to the establishment of high-speed PLC equipment, effective the same day. A similar permission for PLC equipment was given to Mitsubishi Electric, Line Co. and Matsushita Electric Industrial Co. by the Kinki Bureau on March 12 and 19; to Tokyo Electric Power Company by the Kanto Bureau; and to Mitsubishi Electric Corp. by the Hokkaido Bureau.

How JARL will handle new developments
JARL has sounded the alarm bell regarding potential interference from PLC. For example, we have conducted joint experiments with ARIB (Association of Radio Industries and Businesses) and taken part in demonstration tests of the Association on Power-Line Carrier Communications Equipment. The Committee on Electromagnetic Environment of JARL has played a leading role in these experiments with the cooperation from many JARL members and manufacturers which belong to JAIA (Japan Amateur Radio Industries Association). The committee has testified to HF interference caused by PLC. The results had a strong impact on the conclusion the association announced in August 2002.

Moves to new experiments
The high speed power line communication promoters' alliance, "PLC-J" was inaugurated in March 2003 with a view to co-existence between PLC high speed technology and existing systems, and to the early commercialization of PLC in Japan. Its secretariat is located in ARIB with members totaling 26 as of April, 2004. PLC-J says that it is necessary to carry out joint experiments with amateur radio and radio wave astronomy quarters in order to develop interference restricting technology and study how coexistence with existing radio systems should be pursued. In November 2003, JARL held an initial meeting with PLC-J. Subsequent meetings took place in February and March 2004. Discussions were focused on: the committee on electromagnetic environment to represent the JARL side in joint experiments; study of measuring methods in anechoic chambers (rooms made to absorb any radio waves entering the room from the outside world) and fields; and how to evaluate experiments in fields on the basis of the results to be obtained in radio wave darkrooms. JARL has held consultations with PLC-J purely out of concern to see the development of technology designed to restrict interference which has tremendous adverse effects on the operation of HF amateur radio.

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The Japan Amateur Radio League, Inc.