Researchers hail long range Whitespace breakthrough

NICT and Hitachi Kokusai achieve "historic breakthrough" in long-range broadband communications in TV White Space.

Japan’s National Institute of Information and Communications Technology(NICT) and Hitachi Kokusai have said that they have successfully trialled long-range broadband communications in TV white space spectrum, achieving a “historic breakthrough”.

The trail was conducted using IEEE 802.22-based and IEEE 802.11af-based systems, with NICT and Hitachi observing 5.2 Mbps downstream and 4.5Mbps upstream data rates over a 12.7 km link between an 802.22-based base station and customer premises equipment.

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. A statement from the company said they demonstrated applications such as video monitoring of roads and cliffs and video telephony in a mountainous area where there was no wired or broadband wireless Internet connection available. The companies think these achievements demonstrate the feasibility of applying Whitespace technology to provide broadband services in rural areas and to support communications in case of disasters.

This trial was conducted under a contract of R&D for broadband access in white space that was entrusted to NICT and Hitachi Kokusai by the Ministry of Internal Affairs and Communications, Japan.

Trial results:
1. IEEE 802.22-based system successfully communicated over a 12.7-km stretch between the base station and customer premises equipment. Throughput was 5.2 Mbps in downstream and 4.5 Mbps in upstream.

2. Multihop network successfully constructed. The network is constructed using IEEE 802.22 wireless link and IEEE 802.11af wireless link. IEEE 802.22 is used for backbone link and IEEE 802.11af is used for expansion of service area. Wireless LAN, based on conventional IEEE 802.11b/g/n in 2.4 GHz band, is attached to IEEE 802.11af station through which conventional off-the-shelf devices are connected to the Internet. Using the devices, NICT and Hitachi Kokusai have demonstrated availability of web access and conversation via video telephone.

3. An original function has been 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.

Additional information about the trial will be presented at the Super WiFi Summit in Miami, Florida, from January 29 to 31, 2014.

WRAN is aimed at rural area broadband service and coverage within a radius of 10 km to 40 km.

White space is geographically or temporally unused licensed radio spectrum. Secondary utilisation of the spectrum is permitted subject to ensuring that there is a low probability of harmful interference to incumbent service.

IEEE standard 802.22 was standardised for wireless regional area network (WRAN) on July 2011. WRAN is aimed at rural area broadband service and coverage within a radius of 10 km to 40 km.

IEEE standard 802.11af is aimed at wireless LAN operation in white space. IEEE 802.11af draft standard will update and complete the standard by 2014.

Multihop network is a network configuration using relay terminal to connect terminals which cannot directly transmit. Some multihop networks use different systems among links. It can provide flexible network construction and easily satisfy respective specifications of links such as distance, transmission speed.