Feeds

Smart radios still too dumb

TV white space defies boffins

High performance access to file storage

More than three years ago, your reporter got a good taste of how miserable technology utopians can be.

It was at Intel's Developer Forum in San Francisco, and the debate was about liberating analog TV spectrum for exciting new digital uses. The analog switchover is slated for February 2009.

On behalf of Microsoft, Google, and Intel, the technology evangelists argued that smart radios were here, but the evil regulator the FCC wouldn't permit them to deploy the technologies. Broadcasters countered that these experimental new technologies caused interference with their signals (see Abolish Free TV - Intel).

In the hallways afterwards, one delegate and deregulation evangelist couldn't understand why the FCC couldn't just confiscate the spectrum from the TV broadcasters and be done with it?

"Why do the broadcasters need any spectrum at all?" she asked.

Because free TV is one of the few pleasures some Americans can afford, perhaps. A slightly less arrogant and more technically adept argument was advanced instead, which claimed that the space between allocated TV channels was "beachfront property". Instead, the regulator copped it - it was all the fault of the FCC's "command and control" outlook.

(The deregulation fanatics want a spectrum free-for-all and dream of the FCC being scrapped. The FCC is permitting fixed WSDs (white space devices) from 2009, but the industry wants mobile handheld WSDs to be permitted too.)

Now, agile radio has been tested and found to be not quite so agile as its proponents touted.

Hiss, crackle

At the end of July, the FCC's engineering office published two sets of results from a four month trial of agile radio equipment submitted by the "White Space Coalition", which includes Microsoft, Google, Intel, Dell, and HP.

"Depending on the effectiveness of shielding of a TV receiver's tuner, emissions within a broadcast white space (i.e., within an unused broadcast channel) could potentially cause co-channel interference to a TV receiver tuned to a digital cable channel that overlaps the spectrum of the white-space device emission," the FCC noted.

The lab found that the spectrum sensing of the equipment it tested couldn't detect the white space with sufficient accuracy.

For one prototype sensor, "the results of the bench test for determining the baseline minimum detection sensitivity demonstrates that the device will not meet the manufacturer-specified threshold of -114 dBm (or the IEEE 802.22 proposed threshold of -116 dBm for fixed devices) and in fact, fails to meet both of the thresholds by about 20 dB. The results of the field tests also demonstrate inconsistent performance", noted the FCC. The manufacturer may have misread the spec, it suggests. The sensor also failed to detect the presence of a wireless microphone at all.

A second prototype sensor performed to the 114 dBM but got confused when a second DTV channel was turned on - the manufacturer asked it be excluded from more real-world tests. This prototype also failed to pick up a wireless mic, except on the two lowest channels. Both were also severely hampered by the microphones themselves.

Tests of a prototype transmitter also demonstrated interference, and generated some skepticism from engineers whether the filtering required to avoid knocking out TV signals can be implemented in a real product.

So smart radios have a long way to go, and this white space looks less like a "beachfront property" and more like a Cambodian minefield.

Microsoft told the Washington Post today that it had given the FCC a successful demonstration last week - and insisted it will all work out in the end.

As soon as it's got the pesky physics sorted out. ®

High performance access to file storage

More from The Register

next story
A black box for your SUITCASE: Now your lost luggage can phone home – quite literally
Breakfast in London, lunch in NYC, and your clothes in Peru
Broadband Secretary of SHEEP sensationally quits Cabinet
Maria Miller finally resigns over expenses row
Skype pimps pro-level broadcast service
Playing Cat and Mouse with the media
Beat it, freetards! Dyn to shut down no-cost dynamic DNS next month
... but don't worry, charter members, you're still in 'for life'
EE dismisses DATA-BURNING glitch with Orange Mail app
Bug quietly slurps PAYG credit - yet EE denies it exists
Like Google, Comcast might roll its own mobile voice network
Says anything's possible if regulators approve merger with Time Warner
Turnbull leaves Australia's broadband blackspots in the dark
New Statement of Expectations to NBN Co offers get-out clauses for blackspot builds
Facebook claims 100 MEEELLION active users in India
Who needs China when you've got the next billion in your sights?
prev story

Whitepapers

Securing web applications made simple and scalable
In this whitepaper learn how automated security testing can provide a simple and scalable way to protect your web applications.
Five 3D headsets to be won!
We were so impressed by the Durovis Dive headset we’ve asked the company to give some away to Reg readers.
HP ArcSight ESM solution helps Finansbank
Based on their experience using HP ArcSight Enterprise Security Manager for IT security operations, Finansbank moved to HP ArcSight ESM for fraud management.
The benefits of software based PBX
Why you should break free from your proprietary PBX and how to leverage your existing server hardware.
Mobile application security study
Download this report to see the alarming realities regarding the sheer number of applications vulnerable to attack, as well as the most common and easily addressable vulnerability errors.