法人別リリース

NICT Develops World's First IEEE802.11af-compatible Baseband IC for TV White-space Wireless LAN Syst

NICT — Wed, 16 Dec 2015 15:00:55 +0900

TOKYO, Dec. 16, 2015 /Kyodo JBN/ --
National Institute of Information and Communications Technology of Japan (NICT)
NICT Develops World's First IEEE802.11af-compatible Baseband IC for TV White-space Wireless LAN Systems
- Downsized Device Driven by USB Power Realized at Low Cost, 1/10 of Level of Previous Gear -

The National Institute of Information and Communications Technology (NICT) has successfully developed the world's first baseband IC applicable to TV white-space wireless LAN (WLAN) systems. This prototype IC conforms to IEEE802.11af that is the international standard of the WLAN system in the TV white-space spectrum. In addition, NICT has successfully prototyped a card-type communication device in an all-in-one package including an antenna. This card-type device can be driven by USB power and operated by inserting it into the USB port of an off-the-shelf PC.

Among the achievements, NICT:
- Developed world's first baseband IC for TV white-space WLAN systems based on IEEE802.11af standard.

- Prototyped small-size communication device measuring 1/30 of size and weight, and consuming 1/15 of power in comparison with previous devices.

- Makes commercial deployment easy for white-space WLAN systems by cost reduction to 1/10 or less.

The prototype IC contributes to substantial size and cost reductions for communication devices and enables easy implementation in/with other communication devices as a general component, and thus commercial deployment of a TV white-space WLAN system is expected at low cost.

Background
From the viewpoint of effective use of limited spectrum resources, TV white-space (TVWS) utilization has been studied in various countries and regions due to its superior radiowave propagation characteristics. NICT has also contributed to the standardization of IEEE802.11af that defines specifications of WLAN systems in the TV band. Furthermore, NICT has developed box-type communication devices based on the IEEE802.11af standard and has been taking the lead to demonstrate the practicality of the TVWS communication technology.
On the other hand, the same convenience and simplicity as the traditional WiFi system are required for commercial deployment, and thus communication devices small in size and low in power consumption are strongly required as well as easy installation.

Achievements
NICT has successfully developed a baseband IC based on the IEEE802.11af standard. By replacing the FPGA for baseband signal processing with the new IC, it becomes easier to prototype downsized communication devices with low power consumption. In addition, it becomes easy to implement the IC in/with other communication devices as a general component. Further cost reduction is also expected for contribution to the commercial deployment of the white-space WLAN technology.
Furthermore, NICT has successfully prototyped card-type communication devices small in size and low in power consumption at low cost. The card-type device meets the BPSK and QPSK specifications of IEEE802.11af, enabling a maximum communication speed of about 2.6 Mbits/s by using two units of the device. Other main features of this prototype are as follows.
(1) By installing the baseband IC, downsizing to1/40, weight reduction to1/30 and power-saving to 1/15 are achieved in comparison with previously developed box-type devices. The prototyping expense is also reduced to less than 1/10.
(2) The transmission signal waveforms of the device meet legal TV white-space regulations in foreign countries, including the United Kingdom (Up to 100mW is available) and the United States (Up to 50mw is available).
(3) This device has a USB interface as is the case with the common card-type communication devices, and can be operated by USB power.
(4) Available in a simple, all-in-one package including an antenna.
(5) This device can be operated in both access point and station modes. By using multiple devices, it is easy to deploy a network of white-space WLAN systems.

These features enable easy installation in any location where user traffic is congested for effective load-balancing. In addition, superior propagation characteristics of the TV band have the potential to establish communication infrastructure in some regions with difficulties in the deployment of wired networks and to reduce the number of devices in comparison with conventional wireless networks.

Please visit the following URL
(http://www.nict.go.jp/en/press/2015/12/16-1.html)

Philippines Adopts NICT's TV White Space Database for Free Wi-Fi Project

NICT — Thu, 07 May 2015 15:00:31 +0900

TOKYO, May 7 /Kyodo JBN/ --
National Institute of Information and Communications Technology of Japan (NICT)
Philippines Adopts NICT's TV White Space Database for Free Wi-Fi Project
- Accelerating Project for Free Wi-Fi Internet Access at Public Places in Philippines -

The National Institute of Information and Communications Technology of Japan (NICT, President: Dr. Masao Sakauchi) and the Information and Communications Technology Office of the Philippines (ICTO (*1), Executive Director: Louis Napoleon C. Casambre) announced on May 7 that they have concluded a license agreement to provide NICT's TV White Space (*2) technologies for ICTO. ICTO is planning to deploy Free Wi-Fi Internet Access at Public Places (*3) in the Philippines and expecting the TV White Space as an effective frequency band for wireless networking at the project. NICT will further cooperate with ICTO in implementing the TV White Space technologies required for the project, based on the MOU between NICT and ICTO.

-- ICTO of the Philippines is planning to deploy free Wi-Fi Internet access at public places.
-- ICTO is focusing on utilization of TV White Space for the project.
-- Both have signed a license agreement to provide ICTO with NICT's TV White Space technology.

- Background

ICTO of the Philippines is promoting a project to deploy wireless network infrastructure to provide free Wi-Fi Internet access in public places all over the country. ICTO has decided to utilize White Spaces in the TV band for wireless networking in the project particularly for underserved and unserved areas. In utilizing TV White Space, it is crucial to operate equipment carefully so as not to interfere with TV broadcastings. To avoid such interference, the White Space Database (WSDB) (*4) is needed for analyzing available TV channels at each location. Meanwhile, NICT has been developing WSDBs which satisfy the regulations of some different countries around the world for the purpose of technical evaluations, since the WSDB is regarded as one of the essential technologies to utilize the TV White Space. In response to the request from ICTO, NICT signed an MOU with ICTO in March 2015. Since then, both have engaged a series of discussions aiming to exploit NICT's WSDB technologies for free Wi-Fi Internet access in public places.

- Achievements

NICT and ICTO have concluded a license agreement, providing ICTO with the WSDB developed by NICT. This WSDB stores all the TV broadcasting information and calculates the broadcasting areas, according to the geography of the Philippines. The WSDB is capable of listing up TV channels which are available for operating equipment at specified locations. In the future, it is expected that the equipment sends its location to the WSDB, the WSDB sends back available channels to the equipment, and the equipment automatically starts operation in the TV White Space. The Philippines has started terrestrial TV broadcasting services since February 2015 using the ISDB-T system developed in Japan. Accordingly, the WSDB also supports the radio propagation model for the ISDB-T system that is used in Japan to calculate TV broadcasting areas.

- Future perspectives

NICT will continuously cooperate with ICTO by providing TV White Space technologies required to conduct the ICTO's project based on the MOU between NICT and ICTO. For the use of TV White Space, it is necessary that systems should be operated carefully depending on the circumstances of each country. NICT will continue R&D on TV White Space technologies so that they are flexibly applicable to various requirements.

NOTE: ICTO is planning to demonstrate the WSDB at the Global Summit 2015 hosted by Dynamic Spectrum Alliance on May 6-8, 2015. For the details of the Global Summit 2015, please see the following URL: http://www.dynamicspectrumalliance.org/summit.html

Trials of TV White Space Communications at 40Mbps in Central London

NICT — Mon, 28 Jul 2014 15:00:09 +0900

TOKYO, July 28 /Kyodo JBN/ --
The National Institute of Information and Communications Technology
Trials of TV White Space Communications at 40Mbps in Central London
- with Qualified White Space Database under UK Ofcom Pilot -

-- Successfully deployed a 3.7 km link between two locations, and a broadband wireless communications link at more than 40 Mbps throughput, both in central London - a large city which has many TV broadcasters and many active wireless microphone users.
-- Information about available channels and maximum transmission power in each channel is provided by a database developed by NICT and has passed the qualification tests for the Ofcom's TV White Spaces Pilot.
-- Contributions to the development of white space communications regulations of the UK and other countries are expected

The National Institute of Information and Communications Technology (NICT, President: Dr. Masao Sakauchi) has successfully deployed the mobile broadband communications systems at more than 40 Mbps throughput, and has successfully established a 3.7km link between two locations within the framework of the TV White Spaces Pilot organized by Ofcom, the communications regulator of the UK. The trials of NICT systems have been deployed in central London, a big city which has many incumbents to be protected, for example TV broadcasters and active wireless microphone users. NICT has also successfully developed a white space database which passed the qualification tests to be included in the Ofcom's databases list. This database provides protection from interference to the incumbents by calculating and providing information about available channels and maximum transmission power in each channel to the white space systems. NICT's trials which deploys TV white space mobile broadband communications based on database information in a crowded city is the first of its kind. The experiences obtained during the trials are expected to contribute to the development of TV white spaces regulations in the UK as well as other countries in the world.

Background
Using TV white spaces is being considered as one of the potential solutions to the high demands on multi-user support and high speed to broadband wireless communications systems. The Ofcom, an independent regulator and competition authority for the UK communications industries has started the TV White Spaces Pilot which provides an opportunity for the stakeholders to conduct tests with their systems and to provide feedbacks to the development of white space communications regulation. In order to join the pilot, the devices have to conform to a set of specifications determined by ETSI which make sure that they will not interfere to the incumbents in the TV bands, while the databases have to conform to a set of specifications determined by Ofcom which requires them to provide operational parameters to the devices. NICT joined the Ofcom's pilot as both device developer and database developer. Because of the intensive and dynamic use of the spectrum in a large city, it is a challenge that the database uses the most updated incumbents' information to calculate the operational parameters for the devices in real-time, and the devices regularly communicates with the database to exchange operational parameters.

Achievements
The antenna deployed at the roof of a building in Denmark Hill for the 3.7 km link establishment.
NICT has successfully established the 3.7 km wireless link between two locations, and has successfully achieved more than 40 Mbps throughput for broadband mobile systems in the TV bands. Both trials have been deployed in central London, a crowded city where the white space systems have to avoid interference to a large number of incumbents e.g. broadcasting users and PMSE (wireless microphone, in-ear monitor etc.) users. Using operational parameters provided by a database and successfully deploying mobile broadband communications system in a large city is the first trial of its kind. The details are as follows:

-- NICT has developed IEEE 802.11af-based system and established wireless connection between two locations separated by 3.7 km in central London. NICT has developed an LTE-based system and provided high throughput at more than 40 Mbps between a base station and a mobile terminal in central London. Both of the systems developed by NICT conform with the ETSI specifications which defines a strict level of unnecessary power emissions in neighboring channels.

-- NICT has implemented a TV white space database according to Ofcom's specifications. The database calculates and provides operational parameters to the white space systems by taking into account the dynamically changed information about spectrum usage of the incumbents
such as TV broadcastings and wireless microphones. The operational parameters include locations, occupied channels, transmission power and transmission.

Future prospects
Based on the experiences and the results obtained from the trials, NICT plans to improve the performance of the devices and the database. NICT also expects to contribute these experiences to the development of white space relevant regulations in other countries, as well as to transfer their white space technologies to the stakeholders.

The detailed information is on the web page
http://www.nict.go.jp/en/press/2014/07/24-1.html

Alleviating Overcapacity, Specially Developed Smartphone Utilizing TV Whitespace with LTE Technology

NICT — Mon, 24 Mar 2014 15:00:19 +0900

TOKYO, Mar. 24 /Kyodo JBN / --
The National Institute of Information and Communications Technology (NICT)
Alleviating Overcapacity, Specially Developed Smartphone Utilizing TV Whitespace with LTE Technology
-Invention of a pocket-sized and lightweight smartphone with LTE technology for efficient frequency utilization
-Capable of selecting and switching between an LTE system using TV whitespace and commercial LTE networks
-Developed to share the load burden of current mobile communications with TV whitespace, alleviating overcapacity

With the ever increasing number of devices on increasingly overloaded networks, practical ways to relieve mobile communication traffic while maintaining speed and efficiency are more relevant now than ever before. In response to this, the National Institute of Information and Communications Technology (NICT) has succeeded in developing a specially made smartphone that can operate in TV whitespace with LTE (Long Term Evolution) technology.

This new smartphone incorporates two SIM slots, one for the NICT-developed LTE system for TV whitespace and the other for commercial LTE networks. Using software, the phone selects and smoothly switches between the LTE systems, which are based on 3GPP standard release 8. Standby times are 290 hours for TV whitespace and 440 hours for normal LTE networks. The phone also features a talktime of more than 10 hours.

"The smartphone we developed realizes a TDD LTE system with an expanded frequency range to include bands from 470MHz to 710MHz," said Dr. Kentaro Ishizu, senior researcher of the whitespace project. "It's lightweight and handheld for portability, has the same functions as the latest products now on the market, and its standby and talktimes last long enough for commercial use."

"By combining this smartphone with whitespace database-connected base stations (eND-B) we have already developed, we can increase LTE spectrum without causing interference with incumbent systems in the TV band, which means we can use the spectrum more efficiently and effectively," said Dr. Hiroshi Harada, director of NICT's Smart Wireless Laboratory. "We believe our development of this smartphone will contribute to the global development of LTE systems that utilize TV whitespace."

The detailed information is on the web page
http://www.nict.go.jp/en/press/2014/03/19-1.html

NICT, Hitachi Kokusai Electric Achieve Historic Breakthrough in Long-range Broadband Communications

NICT — Thu, 23 Jan 2014 14:02:20 +0900

TOKYO, Jan. 23 / Kyodo JBN/ --
The National Institute of Information and Communications Technology (NICT)
NICT, Hitachi Kokusai Electric Achieve Historic Breakthrough in Long-range Broadband Communications in TV White Space
The National Institute of Information and Communications Technology (NICT, President: Dr. Masao Sakauchi) and Hitachi Kokusai Electric Inc. (Hitachi Kokusai, President and Chief Executive Officer: Manabu Shinomoto) recently succeeded in the world's 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. They 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 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.

Background
Demand for broadband communication services has been growing in rapidly diffused information society. Unfortunately, the services have not sufficiently provided in many areas such as mountainous areas and remote islands. To provide the services, a wireless system is required as a cost effective service comparing to wired networking. The wireless system is also required for flexible and quick construction of network, when a disaster strikes and infrastructure is damaged. 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. In these circumstances, NICT and Hitachi Kokusai are developing IEEE 802.11af and IEEE 802.22 based wireless systems, respectively.

Achievement
NICT and Hitachi Kokusai had confirmed a success in long-range wireless communications by using IEEE 802.22 and IEEE 802.11af based systems in Tono City, Iwate Prefecture, Japan. They have observed following 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 is 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.

World's First Portable Tablet Terminal in TV White Spaces

NICT — Tue, 27 Aug 2013 14:01:12 +0900

TOKYO, Aug. 27 /Kyodo JBN/ --
National Institute of Information and Communications Technology (NICT)
World's First Portable Tablet Terminal in TV White Spaces
- High-speed Communication by Automatic Utilization of Available White Spaces -

The National Institute of Information and Communications Technology (NICT) has developed the world's first portable-size tablet terminal that enables IEEE802.11-based radio communication in TV bands (470-710 MHz). This tablet terminal utilizes a WLAN system for radio communication in TV bands with an inquiry in the white-space database developed by NICT. The original 2.4 GHz band of a WLAN system is also available and it is possible that the tablet terminal automatically selects the radio communication band according to data traffic, etc. through control by the network manager. The white-space utilization by portable devices achieves not only fixed-point communication but also mobile communication, and contributes to the further effective use of frequency resources.

Background
Due to the explosive growth of mobile portable devices such as smartphones and tablet terminals, communication traffic has been increasing and a frequency resource shortage problem has been aggravating. To solve this problem, utilization of TV white spaces is studied and the establishment of radio rules designed for TV white-space operation has been started in the U.S., the U.K., etc. NICT has contributed to standardization on various radio communication systems utilizing TV white spaces, and has developed stationary prototypes based on the standards. Although future TV white-space utilization by portable devices will contribute to the further effective use of frequency resources, it is difficult to miniaturize components and circuits for portable devices due to its lower operational frequency than existing WiFi or cellular bands and its relatively wide frequency range of 470-710 MHz. In addition, technology to avoid interference with TV broadcasts is necessary to be implemented in portable devices. On the other hand, propagation characteristic evaluation supposing practical operation is required for the feasibility study on TV white-space utilization.

Achievement
NICT developed the world's first portable-size Android tablet terminal that enables radio communication in TV bands. This tablet terminal is originally based on an off-the-shelf terminal and a frequency converter newly developed by NICT is implemented for utilizing TV white spaces. Radio communication in both TV and 2.4 GHz bands is available with an original WLAN system (IEEE802.11b/g) and Internet access is also possible through the white-space WLAN base station developed by NICT. In addition, this tablet terminal can operate in the frequency considered not to interfere with TV broadcasts according to calculation results provided by the white-space database developed by NICT, and can automatically select the optimal frequency according to data traffic, etc. through control by the network manager.

Some other functions are implemented in this tablet terminal as below.
1. A function to display the white-space availability of each channel and the terminal location on a map by acquiring information on primary users (TV broadcasters) from the white-space database.
2. A power control function for the different limitation of output power according to white-space status such as a location and time.

Future prospects
Mobile communication in TV white spaces has many subjects. For example, a white-space judging method for avoiding interference with TV broadcasts is required. NICT will evaluate the propagation characteristic using this tablet terminal and offer the information that contributes to a technical reference and a rule designed for TV white-space operation. Furthermore, NICT continues to the standardization activities of wireless communication systems utilizing TV white spaces and promotes the development of portable devices based on such standardized communication systems by applying elemental technologies implemented in this tablet terminal.

World's First TV White Space Prototype Based on IEEE 802.22 for Wireless Regional Area Network

NICT — Wed, 23 Jan 2013 16:00:32 +0900

TOKYO, Jan. 23 /Kyodo JBN/ --
National Institute of Information and Communications Technology (NICT)
World's First TV White Space Prototype Based on IEEE 802.22 for Wireless Regional Area Network
The National Institute of Information and Communications Technology (NICT), Hitachi Kokusai Electric Inc. and ISB Corporation have developed the world's first prototypes of base station (BS) and consumer premise equipment (CPE) based on the IEEE 802.22 standard operating in TV White Spaces (TVWS) (470 MHz - 710 MHz). The developed prototypes will provide broadband wireless access to underserved and unserved regional areas around the world as well as bringing reliable backup broadband communications in emergency, which will follow the worldwide trend of promoting the TVWS for wireless communication systems.

Background
From replacing the current analog television (TV) technology with digital television technology, some of the spectrum previously used by analog television become vacant referred to as TV White Space (TVWS). The Federal Communications Commission (FCC) in the United States, the Office of Communications (Ofcom) in the UK, and the Ministry of Internal Affairs and Communications in Japan have initiated opening up the TVWS to wireless communication systems for efficient reuse of the unused TV spectrum, which is based on non-interfering with broadcast incumbents' operation. The IEEE 802.22 Working Group has published the IEEE 802.22-2011 standard for TVWS broadband wireless access to regional areas where it is most needed and where the TV spectrum is least used. In particular, the IEEE 802.22 systems offer around 10 times the coverage of Wi-Fi as well as enable to provide reliable backup broadband communications in emergency. However, there is no TVWS systems based on the IEEE 802.22-2011 satisfying the FCC spectrum requirements.

Achievements
The NICT and Hitachi Kokusai Electric Inc. have developed the world's first prototype devices of base station (BS) and consumer premise equipment (CPE) verifying the physical layer (PHY) and the medium access control (MAC) layer design based on the IEEE 802.22 standard in the TVWS (470 MHz - 710 MHz). The PHY part developed by Hitachi Kokusai Electric Inc. (Note 1) allows the devices to use vacant TV bands over the frequency range from 470-710MHz, the MAC layer part developed by NICT provides a medium access method based on point-to-multipoint access with supporting the different QoS levels, and supports cognitive capabilities of interference estimation, geo-location and white space data base (WSDB) access over the IP. The WSDB (Note 2) (http://whitespacetech.isbcorp.com/) provided by ISB Corporation avoids interference to incumbents of TV broadcasters from automatically selecting the non-interfering TV band.

Future prospects
The NICT, Hitachi Kokusai Electric Inc. and ISB Corporation in the future will develop the enhanced technologies based on the IEEE 802.22 standard and also work closely with WhiteSpace Alliance (WSA) (Note 3) (www.whitespacealliance.org) to provide products for worldwide markets. The NICT, Hitachi Kokusai Electric Inc. and ISB Corporation will demonstrate the developed prototype devices at the Super WiFi Summit (Note 4) (www.superwifisummit.com) in Miami, Florida, from January 30 to February 1, 2013.

For more information about the prototype, please see the NICT press release at http://www.nict.go.jp/en/index.html or http://www2.nict.go.jp/wireless/smartlab/index.html .

Remarks
All standard organization, alliance, product, and service names that appear in this press release are trademarks or registered trademarks of their respective owners.

Notes:
(1) The PHY part developed by Hitachi Kokusai Electric Inc. was conducted under a contract of R&D for broadband access in white space, organized by the Ministry of Internal Affairs and Communications, Japan.
(2) The WSDB provided by ISB Corporation is based on the technologies of WSDB by NICT (Press release: http://www.nict.go.jp/en/press/2012/06/07en-1.html). Based on the technologies, ISB Corporation newly developed a product that meets commercial requirement and is complied with U.S TVWS database requirements. (http://whitespacetech.isbcorp.com/)
(3) White Space Alliance (WSA) is an international alliance to promote the development, deployment and use of standards based products and services as a means of providing broadband capabilities via White Space spectrum. (http://www.whitespacealliance.org/)
(4) Super Wi-Fi Summit is an international event to create a wealth of new opportunities in the White Space spectrum for consumers, enterprises, service providers and device manufacturers. (http://www.mobilitytechzone.com/super-wifi/)

World's First TV White Space WiFi Prototype Based on IEEE 802.11af Draft Standard Developed

NICT — Wed, 17 Oct 2012 14:00:24 +0900

TOKYO, Oct. 17 /Kyodo JBN/ --
National Institute of Information and Communications Technology (NICT)
World's First TV White Space WiFi Prototype Based on IEEE 802.11af Draft Standard Developed
The National Institute of Information and Communications Technology (NICT), Japan, has developed the world's first WiFi prototype in the TV White Space (TVWS) (470 MHz~710 MHz) based on the IEEE 802.11af draft specification. IEEE 802.11af is currently the only task group (TG) under the IEEE 802.11 working group (WG) for WiFi technologies in the TVWS. The developed system is the first prototype that verifies the physical (PHY) and media access control (MAC) layer design of the draft specification, following the worldwide trend of prompting the TVWS for wireless communication systems.

Background
Recently, many countries are moving to replace the current analog television technology with digital television (DTV). For example, the Federal Communications Commission (FCC) in the United States derived the transition to DTV successfully on June 12, 2009. As a consequence, broadcasters would no longer use some parts of the radio spectrum currently used by analog TV technology. Regulators have undertaken initiatives to open up some of the currently unused broadcast TV spectrum between 54-698 MHz referred to as TV White Space to wireless communication systems. The Office of Communications (Ofcom) in the UK and regulators in many other countries are also following the same trend, encouraging organizations around the world to start efforts to prompt research and standardization activities.
IEEE 802.11af TG was formed in 2009 under IEEE 802.11 WG. The target is to define modifications to both the 802.11 PHY and MAC layers to meet the legal requirements for channel access and coexistence in the TVWS. The 802.11af has been closely following various regulations in order to prompt the WiFi technologies in TVWS worldwide. It is widely considered as one of the most promising technologies for the TVWS. In September 2012, the 802.11af released its first stable draft standard (Draft 2.0).
NICT is one of the most active contributors and leading parties of the 802.11af.

Achievements
The developed prototype is the world's first WiFi system in TVWS based on the IEEE 802.11af draft standard. It verifies the physical (PHY) and medium access control (MAC) layer design of the draft specification. One of the OFDM PHY modes that take a single 6 MHz TV channel to operate is implemented with transmission power of 20 dBm. The prototype has an interface and co-worked with White Space Data Base (WSDB) developed by NICT and the full MAC specification of the secured protocol is implemented for primary user (licensed TV broadcaster) protections. The prototype also has an interface and co-works with the Registered Location Secure Server (RLSS) that is defined in the 802.11af draft standard to avoid interference with other white space users (secondary users). NICT has developed the RLSS server. It is approved that the primary users and secondary users operating in the co-channels can be sufficiently protected.

Future prospects
There are many benefits of 802.11af systems compared with other current WiFi technologies. Firstly, in view of the fact that 802.11af systems operating the TVWS use frequencies below 1 GHz, it would allow for much longer distances to be achieved. Current WiFi systems use frequencies in the ISM bands -- the lowest band is 2.4 GHz and the signals are easily absorbed. Secondly, by operating in the TVWS, the usable spectrum is much broader than that of ISM bands when efficiently aggregated. Looking at these benefits, it is widely believed that 802.11af systems offer sufficient advantages to enable a broad market.

With the evolution of regulations regarding the TVWS worldwide, it is expected IEEE 802.11af may adapt to those regulation updates and complete the standard by 2014. We are now working on the next revision to implement the full PHY specification and new features come along with the regulatory updates. We are also looking for the opportunities for technical transfer.

For more information about the prototype, please visit the NICT press release at http://www.nict.go.jp/en/index.html or http://www2.nict.go.jp/wireless/smartlab/index.html .

Remarks
All standard organization, alliance, product, and service names that appear in this press release are trademarks or registered trademarks of their respective owners.