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Thursday, January 23, 2014
NICT, Hitachi Kokusai Electric Achieve Long-range Broadband
Communication Using The White Space
The National Institute of Information and Communications Technology (NICT) and Hitachi Kokusai recently succeeded in the first field trial in which long-range broadband communications in the TV white space was confirmed by using IEEE 802.22-based and IEEE 802.11af-based systems.
In the trial, NICT and Hitachi Kokusai observed successful
downstream and upstream data transmission at 12.7 km distance
between IEEE 802.22-based base station and customer premises
equipment, at speeds of 5.2 Mbps and 4.5Mbps, respectively.
In addition, NICT and Hitachi Kokusai constructed a multihop
network by using IEEE 802.22 as a backbone link and IEEE
802.11af, which is connected to it, to expand its connection
area. Wireless LAN, based on conventional IEEE 802.11b/g/n in
2.4 GHz band, was attached to IEEE 802.11af station through
which conventional off-the-shelf devices were connected to the
Internet. Using the devices, NICT and Hitachi Kokusai
demonstrated availability of web access and conversation via
An original function has been also developed based on IEEE
802.22 to operate in multiple channels. With two discontinuous
TV channels to operate at the same time, they have succeeded
in achieving throughput of 15.5 Mbps in downstream and 9.0
Mbps in upstream over 6.3 km.
Demand for broadband communication services in mountainous
areas and remote islands have been problematic. To provide the
services, a wireless system is required as a cost effective
service comparing to wired networking. White space in TV band
(470-710 MHz, in Japan) is expected for long-range
communication whereas a legacy system using higher frequency
such as wireless LAN and cellular systems cover shorter range,
since lower frequency has generally low impact on distance
decay toward obstacles.
The Japanese scientists demonstrated some applications such as
video monitoring of roads and cliffs and video telephone in a
mountainous area where there is no wired Internet connection
available or broadband wireless Internet connection.
These achievements show feasibility of broadband services in
rural areas and supporting communications in case of