Familiar with the term "white space?" If you’re a graphic designer, it’s a no-brainer. But if you’re a television broadcaster or manufacturer/user of wireless microphones, it’s fast becoming an expletive.
The consumer electronics industry has a strong interest in delivering "white space" wireless broadband communication devices to be used in the home to enable wireless media servers and stream everything from HDTV to music and still photos from PCs to HDTVs.
Not a bad idea, but there’s a fly in the ointment: The target frequencies for these white space products are already occupied, primarily by UHF television broadcasts, and secondarily by professional wireless microphones.
Starting in 2007, the FCC’s Office of Engineering Technology (OET) began testing so-called white space prototypes from Microsoft and Philips to see if they could actually scan for and detect activity on TV channels and quickly move to another unused frequency. The prototypes failed so miserably that one manufacturer ostensibly chalked the cause up to "power supply issues." However, a follow-up test produced essentially the same results.
Another round of tests commenced last month. This time, the FCC decided they would eschew the OET laboratories in favor of real world locations that included Patapsco Valley State Park in Elkridge, MD and the Thomas A. Dixon, Jr. Aircraft Observation Area at Baltimore-Washington International Airport, along with multiple private residences in the Baltimore and Washington DC metro area.
The highlight (or lowlight) of the tests took place on August 7 during an NFL pre-season game between the Buffalo Bills and Washington Redskins at FedEx Field in Landover, MD. According to news reports from the Sports Video Group (www.sportsvideo.org), the white space devices under test completely failed to detect existing analog and digital TV broadcasts on occupied UHF TV channels, and "… also failed to detect the presence of wireless microphones when switched on, an occurrence that takes place multiple times during any NFL game."
Oops! Either the manufacturers involved still haven’t figured out how to make their scanning receivers work correctly, or they hoped to repeat the same experiment and get different results. (Albert Einstein once defined that as insanity!) Either way, the odds don’t look good for the FCC to green-light white space operation any time soon.
The problem of shoehorning yet another low-power, unlicensed wireless service into an already-busy part of the RF spectrum will be aggravated by the coming DTV transition, when the core of TV channels in the UHF band shrinks to 14 through 51. Wireless audio manufacturers are trying to figure out whether they can continue to operate above 700 MHz post-transition, and have been testing for possible adjacent-channel interference from ATSC (digital) transmissions for some time now.
The Association for Maximum Service Television (MSTV) and the National Association of Broadcasters (NAB) have weighed in on the issue, urging that the FCC just say "no!" to white space manufacturers, perhaps steering them to another part of the RF spectrum where these products won’t have as much potential to create harmful interference.
With Microsoft, Philips, and other industry giants pushing back, this battle won’t end anytime soon. Home media networks are definitely one of the "next big things" and very few homes in the United States are already wired with LAN connections in every room. Retro installs of Cat5 wire and routers would be expensive and impractical, so wireless is the practical, cost-effective way to go.
The only question is; where will it go?