World's Fastest
Satellite Internet Connection To 45 cm User Terminal Using "KIZUNA"
(WINDS)
(21 April 2008) The Japan Aerospace
Exploration Agency (JAXA) and National Institute of Information and
Communications Technology (NICT) performed a verification of regenerative
switching functions between an ultra small-size user terminal (45 cm-diameter
antenna) and a high-speed small ground station (1.2 m-diameter antenna) using
the onboard multi-beam antenna*1 of "KIZUNA," and confirmed that Internet
protocol (IP) communications with a transmission speed of 155 Mb/s (155 Mega
bit per second) were successfully performed.
The verification
was a part of the initial functional verification jointly conducted by JAXA and
NICT between March 28 and April 7, 2008. It is especially noteworthy that the
transmission speed of 155 Mb/s from a satellite to an ultra small-size user
terminal like the antenna of 45 cm in diameter is the fastest in the
world.
KIZUNA's operations entered the initial functional verification
phase on March 1, and the functions and performance of its onboard equipment
are currently being verified. The functions that have been verified so far
include the automatic tracking control of the multi-beam antenna and the output
of approximately 280 W from the multi-port amplifier.
JAXA will further
perform verification of KIZUNA's special features such as mutual connectivity
across multiple ground stations, transmission at 1.2 Gb/s (1.2 Giga bit per
second), and the functionality of the active phased array antenna.
An
ultra small-size user terminal with a 45 cm-diameter antenna was placed in
Okinawa and a high-speed small ground station with a 1.2 m-diameter antenna was
placed in Tohoku. Data was sent from the 45 cm antenna to KIZUNA at a
transmission speed of 1.5 Mb/s, then sent from KIZUNA to the 1.2 m antenna at a
speed of 155 Mb/s. Data was also sent in reverse, from the 1.2 m antenna to
KIZUNA at 155 Mb/s and then from KIZUNA to the 45 cm antenna at 155 Mb/s.
Throughout these transmissions, KIZUNA was in the regenerative switching
mode*2.
*1 KIZUNA is equipped with two multi-beam antennas, one for
Japan and neighbouring countries and another for the Asia-Pacific region. The
former covers Japan (nine areas total), Seoul, Beijing, and Shanghai. The
latter covers seven cities in the Asia-Pacific region.
*2 The
regenerative switching mode is the mode in which data sent from a ground
station to a satellite is demodulated in the satellite and sent to the
destination ground station. The regenerative switch onboard the satellite is
used for this process. Conventionally, data sent from a ground station had to
be sent to another ground station to be processed and then sent from the
satellite to the destination ground station. By equipping a regenerative switch
similar to a ground station, communication can take place with less redirecting
and therefore at greater speeds.
(source: JAXA)
