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Official
press release on PLC issue in Japan, from Ministry of Public Management, Home
Affairs, Posts and Telecommunications (English)
Internet: http://www.soumu.go.jp/joho_tsusin/eng/Releases/Telecommunications/news020809_3.html
Summary: English summary of
statement from the Japanese Ministry of Public Management, Home Affairs, Posts
and Telecommunications. Japanese
original tetxt is available from the Internet URL above.
Author: MPHPT
Japan's
Government Concluded That It is not suitable to allow HF band for PLC (English)
Internet: http://www.jarl.or.jp/English/4_Library/A-4-1_News/jn0208.htm)
Summary: On April 30, 2002, the Ministry's study group on
PLC held its first public hearing with JARL, Association of Radio Industries
and Business, and others. At the meeting, the results of collaborated field
tests, which were held in January, 2002, were reported. The tests included
monitoring leakage of electric waves from power lines -- specifically in cases
of providing Internet access via power lines to homes. In this way, JARL
actively cooperated with the group. As a result, MPHPT's study group officially
announced in its fifth meeting on July 31 that it is too early to allow PLC
between 2 MHz and 30 MHz due to hazardous effects on HF users. This news was
reported by major newspapers including Yomiuri, Asahi and Mainichi, as well as
the major financial daily, Nihon Keizai Shimbun.
Author: JARL
Campaign Against
Power Line Communications Operating in the HF Bands (English)
Internet: http://www.qsl.net/jh5esm/PLC/JARLcampaignPLCe.pdf
Summary: This paper gives a
tutorial of PLC and presents summaries of the interference level from
measurements made of several access PLC field tests in Japan. Japan has chosen
not to allow access PLC at this time.
Author: JARL, Cosy MUTO,
JH5ESM
Campaign Against
Power Line Communications Operating in the HF Bands (Japanese)
Internet: http://www.qsl.net/jh5esm/PLC/JARLcampaignPLCj.pdf
Summary: This paper gives a
tutorial of PLC and presents summaries of the interference level from
measurements made of several access PLC field tests in Japan. Japan has chosen
not to allow access PLC at this time.
Author: JARL, Cosy MUTO,
JH5ESM
7th International
Symposium on Power Line Communications and Its Applications (ISPLC2003)
(English)
Internet: http://www.darc.de/referate/evm/plc/isplc2003.html
Summary: This is a
short summary of the symposium written by Cosy MUTO, JH5ESM.
Author: JARL, Cosy
MUTO, JH5ESM
On Radio
Interference Assessments of Access PLC System
Internet: http://www.qsl.net/jh5esm/PLC/isplc2003/isplc2003a2-3.pdf
Summary: Access PLC system is considered one of
the "last mile" solutions. However, HF PLCs using overhead distribution would
be an interference source to radio communications services and scientific
observations in this band. This paper describes assessment test results in
Japan. One of them is carried out as a part of government's investigation. Bad
LCL characteristics of mains results large amount of radio interference, and
thus the deregulation in Japan is shelved.
Authors: Cosy MUTO, Norikazu
MORI and Toshiyuki KONDOH
Note: Presented at the
ISPLC2003 Symposium.
On
Radio Interference Assessments of Access PLC System -- Presentation Material
Internet: http://www.qsl.net/jh5esm/PLC/isplc2003/isplc2003a2-3presentation.pdf
Summary: This file is the
presentation material from the above paper.
Authors: Cosy MUTO, Norikazu
MORI and Toshiyuki KONDOH
The following 2 papers were also presented at the ISPLC2003 Symposium:
Interference
measurements in HF and UHF bands caused by extension of power line
communication bandwidth for astronomical purpose
Internet: http://www.qsl.net/jh5esm/PLC/isplc2003/isplc2003a7-1.pdf
Summary: Power line
communication (PLC) system which extends the available frequency bandwidth up
to 30 MHz has been proposed in Japan. The electromagnetic interference problems
on PLC had been investigated by the PLC study group organized by the Ministry
of Public Management Home Affaires, Post and Telecommunications (MPHPT). The
study group held collaborated field experiments of the PLC facility and we
measured interferences caused by the PLC facility in the HF and UHF bands in
order to evaluate the inflences of the expansion of PLC bandwidth on radio
astronomical observations. In the field experiment, two sets of PLC modems (SS
and OFDM) were tested as an access system. During the PLC modems were on, the
HF spectra observed showed strong increase of the noise-floor level, and it was
found that the PLC noise exceeded the level of galactic noise by more than 30
dB. In UHF band, spurious emission around 327 MHz was identified. In both HF
and UHF band, the interferences exceeded the limit of harmful interference
level for radiop astronomical observation which is given in Recommendation
ITU-R TA769-1. Safety distances where the Recommendation was satisfied are
estimated to be 219 km and 12 km at 9.2 MHz and 327 MHz, respectively. PLC
seems to be a harmful interference source for the radio astronomical
observation in both HF and UHF bands.
Authors:
F.Tsuchiya, H.Misawa, T.Nakajo, I.Tomizawa, J.Nakajima, M.Ohishi, M.Tokumaru,
T.Ono and A.Morioka
Sharing
studies between the radio astronomy telescopes and the power line communication
systems in the HF region
Internet:
http://www.qsl.net/jh5esm/PLC/isplc2003/isplc2003a7-4.pdf
Summary:
Radio Astronomy has frequency allocations in 13.36-13.41 MHz and
25.55-25.67 MHz on a primary basis worldwide.
These bands are extensively used by radio astronomers to observe
electromagnetic waves emitted by the Sun, the Jupiter and other large, gaseous
planets in the solar system. The powers from a single PLC system in the above
radio astronomy bands are --33 dBW and --29.2 dBW respectively and therefore the
PLC sytems seem to be a harmful interference source for the radio astronomical
observation in the HF band. It is necessary to keep an adequate separation
distance to avoid harmful inteference to the radio astronomy telescope, and we
calculated the separation distance based on the free-propagation method. We
obtained a value of 424 km. If the PLC
system is widely deployed, it is sure that the interference level increase
greatly and the separation distance will become much larger. Thus it was
recognized that it is quite difficult to share frequencies with the PLC systems
and radio astronomy telescopes, at least, in Japan, and that a new technology
to dramatically reduce leaked emissions from the power lines are crucial for
the PLC systems to coexist with other radiocommunications services.
Authors:
by M.Ohishi, J.Nakajima and M.Tokumaru
Other JARL PLC Web Pages (Japanese)
