Last week, Federal Communications Commission (FCC (News - Alert)) took a critical step forward by announcing the start of the first trial of TV white spaces database. The limited public testing of Spectrum Bridge’s database system is intended to allow the public to access and test the system to ensure that it correctly identifies channels that are available for unlicensed TV band devices, properly registers those facilities entitled to protection, and provides protection to authorized services and registered facilities as specified in the rules.
Commission rules require that unlicensed TV band devices contact an authorized database system to obtain a list of channels that are available for their operation (i.e., channels not occupied by authorized radio services) at their individual locations and must operate only on those channels. The trial of the Spectrum (News - Alert) Bridge database system is scheduled to last for 45 days, ending November 2, 2011. Parties may participate in the trial by accessing Spectrum Bridge’s TV band database test facility here.
While a few years from now many American' laptops, smart phones, and other wireless devices will be able to get online using Super Wi-Fi as a new standard that promises to increase capacity, the bad news is that most people won't be able to use those airwaves to make long-range connections, reports MIT’s (News - Alert) Technology Review. According to MIT Technology Review, a new model for managing America's airwaves was unveiled on Monday as part of a plan by FCC chairman Julius Genachowski (News - Alert) to ease what he calls America's "spectrum crisis." As wireless devices proliferate, Genachowski has repeatedly said, the U.S. needs to free up more spectrum for modern uses, wrote MIT Technology Review.
The super Wi-Fi makes use of the vacant airwaves that lie between existing TV stations' frequencies, which are known as white spaces. However, the Technology Review report indicates that other applications, such as wireless microphones, already have some rights to those frequencies. Hence, it will allow someone who, for example, wants to use a wireless microphone for a musical in Reno, Nevada, to register where he needs to use those airwaves, wrote Technology Review reporter Scott Woolley. “New Super Wi-Fi devices can access that database and make sure not to send out interfering signals. If he doesn't register, he can't be assured of having that spectrum free,” Woolley wrote.
According to Jeff Schmidt, the director of engineering at Spectrum Bridge (News - Alert), which is overseeing the first white-space database, “Right now large parts of the spectrum go to waste because the license holder who controls them has no incentive to let other people use them, even when it doesn't need them. The old system was that [a company] got a chunk of spectrum and used it for its network." He added, "White spaces allow a bunch of dissimilar users to share spectrum efficiently."
The problem, as the database shows, is that the places where spectrum is in the shortest supply—cities where lots of people must share the same airwaves—are also the places with the most TV channels and thus the least available white space,” wrote Woolley.
Under government rules designed to protect local TV stations from harmful interference, high-power Super Wi-Fi signals (up to 4 watts), which can travel for miles, must give TV channels a wide berth, reports Woolley. However, unlike high power signals, low-power super Wi-Fi signals with <40 mW power face fewer restrictions, per Technology Review’s description.
The result is that bigger cities where Most Americans live, zero or one channel will be available for long-range use, even though some 48 potential channels are available for long-range Super Wi-Fi. In rural areas, the longer-range systems could prove a boon, but most of the spectrum will still be off-limits, Technology Review wrote.
.Ashok Bindra is a veteran writer and editor with more than 25 years of editorial experience covering RF/wireless technologies, semiconductors and power electronics. To read more of his articles, please visit his columnist page.
Edited by Rich Steeves