Per molti versi è quella che gli americani chiamano landmark decision, una decisione esemplare, destinata a contrassegnare, d’ora in poi, il territorio del regolatore dello spettro radio. La FCC americana dà il via libera a dispositivi radio che potranno condividere, senza licenza, lo stesso spettro assegnato a operatori che magari hanno pagato caro il diritto a utilizzare (fino a oggi in via esclusiva) le frequenze televisive UHF. Ora che il digitale terrestre televisivo è entrato in funzione anche negli USA, molte frequenze prima occupate dalle tv analogiche vengono lasciate libere. In questi inattesi “buchi” potranno operare le stazioni base del Wi-Fi, rendendo possibile la creazione di servizi di connettività Internet molto interessanti (a 800 MHz le onde radio penetrano meglio all’interno degli edifici e il Wi-Fi può diventare molto più accessibile. La chiamano già il Wi-Fi che ha preso gli steroidi.
I broadcaster non sono affatto contenti, perché oltre ai servizi televisivi su queste stesse frequenze operano i radiomicrofoni di cantanti e attori. Come evitare che questi dispositivi regolamentati non subiscano le interferenze delle future “base station” libere? E qui scatta il fattore davvero innovativo: la FCC imporrà l’uso di sofisticati algoritmi di “spectrum sensing” e di geolocalizzazione. In altre parole, le stazioni base “sapranno” se è possibile trasmettere o si deve cambiare canale. Un primo, importante esempio di radio cognitiva su larga scala. Saranno abbastanza sofisticati questi algoritmi? Solo l’esperienza diretta ce lo dirà.
FCC Approves White Spaces, ‘WiFi On Steroids’
by Wendy Davis, Tuesday, Nov 4, 2008
Kevin J. Martin of FCCIn a move expected to spur broadband growth, the Federal Communications Commission voted unanimously Tuesday to allow the unlicensed use of the white space spectrum.
“Opening the white spaces will allow for the creation of a WiFi on steroids,” FCC chair Kevin Martin said in a statement issued Tuesday. “It has the potential to improve wireless broadband connectivity and inspire an ever-widening array of new Internet based products and services for consumers.”
Some Web companies, including Google and Microsoft, backed the plan– as did broadband access advocates. They say that allowing white spaces to be used for Internet access will encourage companies to create new wireless broadband networks because the radio airwaves are powerful enough to transmit through walls and across large areas.
But TV broadcasters and other users of the spectrum condemned the proposal, arguing that allowing unlicensed devices on vacant radio airwaves will cause interference with TV signals or wireless microphones.
The FCC said Tuesday that new devices on the white space spectrum will not interfere with existing users. “The rules represent a careful first step to permit the operation of unlicensed devices in the TV white spaces and include numerous safeguards to protect incumbent services against harmful interference,” the agency said.
The agency said that it will require new devices to have geolocation and database access capabilities, or alternatively, spectrum-sensing capabilities, in order to prevent interference.
The FCC also said that current users of wireless microphones–including Broadway theaters and others that never obtained licenses –will be able to register their locations in a database. New devices with database capabilities will be able to communicate with the registry, which will tell the devices which portions of the radio airwaves can be used.
Backers of the plan cheered the FCC’s decision. “Today’s vote ushers in a new era of wireless broadband innovation,” Microsoft said in a statement. “Like other unlicensed facilities, which enabled popular technologies such as WiFi and Bluetooth, white spaces will make possible new and creative solutions to a range of broadband connectivity challenges.”
Opponents, including the National Association of Broadcasters, criticized the ruling. “While we appreciate the FCC’s attempt to address significant issues raised by broadcasters and others, every American who values interference-free TV should be concerned by today’s Commission vote,” the group said in a statement.
