The Federal Communications Commission (FCC) announced a publicly accessible database that will be a key step in U.S. trials of white space networking, leveraging spectrum previously occupied by analog T.V. channels. To be operated by Florida-based Spectrum Bridge starting Sept. 19, the database will be tested to ensure it can prevent unlicensed broadband devices from interfering with wireless microphones and vice versa, the agency says.

White space networking — sometimes also known as "WhiteFi" — will rely on radio spectrum that was previously reserved for TV stations. Because available frequencies vary from location to location, the technology will require access points and clients fitted with cognitive radio equipment, which can detect interference and automatically switch frequencies when they need to.

At the end of 2008, the FCC issued a ruling permitting the use of unlicensed devices in the "white spaces" vacated when analog television signals were switched off. The catch is, any new users are not allowed to interfere with any licensed incumbents, which may still include a few TV stations and also include wireless microphones.

Last November, therefore, the FCC approved the concept of databases that would identify incumbent users, including full- and low-power stations, that are entitled to interference protection. The databases, which will be privately owned and operated services, would tell white space devices which TV channels are vacant and may be used at their location.

Subsequently, as we reported in January, Google asked to become one of the white space database administrators. Its proposal to the FCC said it would "cooperate … to develop a process for databases to provide to one another, on a daily basis, information about registered cable TV headends, TV translator station receive sites, operating sites of wireless microphones and other low power auxiliary stations, and fixed white space devices."

We're not sure what the status of Google's proposal is, but the FCC announced Sept. 14 that the first white spaces database is now available for public testing. It will be operated by Lake Mary, Florida-based Spectrum Bridge, the agency added.

Details provided by the agency include the following:

• the public trial goes live at 8:30 a.m. EDT on Sept. 19, 2011, and ends on Nov. 2, 2011
• unlicensed TV-band devices are required to query the database to find a list of channels that are available for their operation
• devices are also required to provide their geographic location via a secure internet connection

Each white spaces database to be trialled will be tested for not less than 42 days to ensure that it is providing accurate results, the FCC says. Data entered during the trial will be treated as temporary experimental data and is not intended to be part of the permanent record, the agency adds.

Background

The FCC has been criticized in the past for its go-slow approach to testing white space networking. Meanwhile, trials are apparently already under way in the U.K., thanks to the Cambridge TV White Spaces Consortium, whose kick-off was announced in June.

Members of the Consortium include not only Spectrum Bridge, but also the BBC, BSkyB, BT, Cambridge Consultants, Microsoft, Nokia, Neul, and TTP. The group is exploiting a special multi-site license from U.K. regulator Ofcom to test white space (a.k.a. "WhiteFi") hotspots at local pubs, other leisure venues, and commercial and residential premises, according to Microsoft.

Microsoft said in June that the white space testing will involve streaming video and audio content from the BBC and BSkyB "to a range of mobile devices, including some from Nokia and Samsung." As far as we're aware, however, there are no relevant chipsets that actually fit inside phones. It appears mobile testing will initially take place via relatively large equipment wired to notebook computers.

Silicon Valley startup Adaptrum has demonstrated relevant prototypes — and was mentioned in a June 27 blog posting about the tests by a Microsoft vice president — but Neul has also created devices that could also be employed. In fact, the Cambridge, U.K. company claimed in late June that its "NeulNET" system (below) was the world's first production WhiteFi System.

The NeulNET devices
(Click to enlarge)

The NeulNET products include a basestation, equipped with a GPS receiver for accurate positioning, plus a 9 x 7.1 x 1.6-inch terminal, the latter battery-operable. Both devices are equipped with Ethernet ports, for connection to a Wi-Fi access point on the one hand and a notebook computer (or other client) on the other.

According to Neul, these devices are suitable for M2M applications, with data rates from 2kbps to 2Mbps, or for rural broadband, with speeds up to 16Mbps. The company says the open "Weightless" standard employed uses time division multiple access (TDMA) to divide up the available capacity on the downlink, and a combination of TDMA and frequency division multiple access (FDMA) on the uplink, allowing "up to one million terminals per basestation."

Neul says NeulNET is compatible with U.S., European, and Japanese TV channel assignments and can eliminate interference to wireless microphones. A proprietary technology cancels signals from distant TV transmitters, the company adds.

Neul was formed in 2010 by some of the founders of Cambridge Silicon Radio, which pioneered the development of single-chip Bluetooth transceivers in CMOS.

Further information 

Once the Spectrum Bridge trial is live on Sept. 19, it will be possible to use the company's website to determine locally available channels for white space networking or wireless microphones. The site also offers a registration procedure for both licensed and unlicensed wireless microphones.

Jonathan Angel can be reached at [email protected] and followed at www.twitter.com/gadgetsense.

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