The National Cable & Telecommunications Association gave the Federal Communications Commission a laundry list of reasons why it doesn't think the commission should allow mobile, or fixed, wireless devices in the so-called TV white spaces until it resolves key interference issues.
While broadcasters have only been lobbying hard against mobile unlicensed devices, the NCTA said current proposals for fixed licensed devices don't pass muster, either, and could create interference to cable systems.
The trade group pointed out that the devices could interfere with reception of distant TV signals at cable headends, for example, which, it argued, are more susceptible to interference from the devices, arguing that such interference could "wipe out" programming to an entire community.
It also argued that allowing the powerful transmitters needed for fixed devices would threaten cable signals.
"The proposals for unlicensed personal and portable devices and for fixed licensed use of the TV bands have the potential to seriously degrade service for cable-television viewers," the NCTA argued in a letter to the FCC. "Rather than spawning innovative services with no harm to others, as white-spaces proponents have touted, the operation of TV-band devices could only confuse consumers and undermine existing innovative cable services.”
But while the NCTA advised the FCC that no proposal fills the bill, in case the commission goes ahead and approves the devices, it wants it to do the following:
• 1) Restrict the operation of portable devices to a maximum of 10 megawatts and prohibit transmissions in the VHF channels given the high probability of direct pickup interference to TV receivers.
• 2) Prohibit operations, at a minimum, on channels 2-4.
• 3) Restrict the operation of fixed devices to at least 400 feet from the external walls of residential buildings.
• 4) Prohibit operation of fixed devices in VHF channels.
• 5) Require spectrum coordination before operation of portable devices on channels adjacent to those being received at headends.
• 6) Of the suggested methods by which fixed and portable devices might automatically determine channel availability, it appears that auto-location (GPS or equivalent), combined with regular access to a reliable database containing geographically indexed lists of available channels, has the potential to provide the flexibility and reliability required to protect headend reception.
The FCC has been testing the use of unlicensed mobile devices both in the lab and in the field.
The agency already expressed a preference for allowing the devices so long as they do not interfere with the digital-TV pictures that will be the new standard for TV distribution.