TV "White Space" Devices Go Nationwide

New action follows December roll-out to eastern states.

TV “white space” devices, which operate on an unlicensed basis in locally vacant TV spectrum, are now authorized nationwide. This is pretty fast, by Government standards; just last December the FCC okayed the first large-scale roll-out to seven eastern states plus Washington, D.C. The class of approved coordinators for the database these devices rely on to find open channels is growing much more slowly. Also growing slowly is the number of FCC-approved devices that can use the service; we count just five so far.

FCC Approves "White Space" Devices in Eastern U.S.

New systems must protect many other services from interference.

Fully four years after adopting rules for unlicensed TV Band Devices (TVBDs), also called “white space” systems, the FCC has authorized roll-out beyond the two small test areas previously approved. Touted by advocates as “Wi-Fi on steroids,” TVBDs can now boot up in New York, New Jersey, Pennsylvania, Delaware, Maryland, Washington DC, Virginia, and North Carolina.

The FCC expects to extend authorization nationwide by mid-January.

TVBDs are required to avoid causing interference to multiple services: broadcast TV; fixed broadcast auxiliary service links; receive sites for TV translators, low power TVs, Class A TVs, and multichannel video programming distributors; public safety and private land mobile; offshore radio telephone; radio astronomy; and “low power auxiliary service,” which includes licensed (and some unlicensed) wireless microphones. 

The complexity of the TVBD rules results from the need to ensure that all of these services can operate unharmed. In many metropolitan areas having multiple TV channels and heavy use of wireless microphones, vacant spectrum for TVBDs is already scarce. The FCC’s ongoing plans to consolidate TV broadcasters onto fewer channels, so as to free up more spectrum for wireless use, will only make things worse.

Simultaneously with the spread of TVBDs into the Middle Atlantic states, the FCC expanded its registration program for wireless microphones from those same states out to the rest of the country, keeping the wireless mic registrations a step ahead of the TVBD roll-out.

FCC Launches Nationwide Registration of Wireless Microphones

Registration is needed to protect qualifying events from interference caused by TV Band Devices

The FCC has expanded its registration program for wireless microphones from the Middle Atlantic states to the rest of the country.   Registration helps to protect qualifying wireless microphones that operate in vacant TV channels from interference caused by TV Band Devices (TVBDs), also called “white space” systems, that likewise use vacant TV slots.

When the FCC established rules for TVBDs, it required those devices to avoid interfering not only with TV stations, but also with several other categories of equipment operating on TV frequencies. The most populous of those, by far, are the wireless microphones that are ubiquitous in TV, stage, and film production.

Most wireless microphones used in TV and films are licensed by the FCC.  Most others – including those used in stage shows, churches, and the FCC meeting room – operated illegally until January 2010, when the FCC authorized low-power models on an unlicensed basis by waiver. (As it considers whether to make those rules permanent, the FCC recently sought to update the record on wireless microphone issues generally.)

Two TV channels in every market are closed to TVBDs, so as to leave room for wireless microphones. Licensed wireless microphones needing additional channels are entitled to interference protection from TVBDs. So are unlicensed microphones on other channels, but only if used for major sporting events, live theatrical productions and shows, and similar occasions that require more microphones than the set-aside channels can accommodate.

To implement protection, qualified events must register in the database that controls which frequencies TVBDs can use at each location. The FCC has authorized the operation of TVBDs in New York, New Jersey, Pennsylvania, Delaware, Maryland, Washington DC, Virginia, and North Carolina, and expects nationwide authorization by mid-January. Those who distribute or use wireless microphones should make sure any needed registrations are in place before TVBDs are deployed in their vicinity.

The details of the registration process are available here. The conditions and procedures are complex; and the FCC cautions that most uses of unlicensed wireless microphone do not qualify for registration. We recommend planning ahead.

Update: Revised "White Space" Rules To Take Effect June 18

Last month we reported on an FCC action that may mark the end of the decade-long “white space” proceeding authorizing the operation of some unlicensed devices in the broadcast television bands. The Commission’s Third Memorandum Opinion and Order (3rd MO&O), released in early April, disposed of a handful of petitions for reconsideration of the agency’s 2010 decision which had in turn tweaked technical “white space” specs adopted back in 2008. The 3rd MO&O has now been published in the Federal Register, which means that, barring any extraordinary intervening event (like the issuance of a stay – the approximate likelihood of which is pretty much zero), the rules as modified last month will take effect on June 18, 2012

FCC Adjusts "White Space" Rules

Minor changes may signal an end to almost a decade of rulemaking.

The FCC has released yet another decision in its long-running effort to implement rules allowing unlicensed “white space” devices in the television bands. The latest revision does not represent any wholesale changes, but will make it easier for some devices to operate.

White space devices (TV Band Devices or TVBDs, in the FCC’s nomenclature) rely on the fact that every location has some TV spectrum not being used. Those vacant frequencies typically show up as white spaces on a map of spectrum occupancy – hence the name. Technical studies show that properly controlled unlicensed devices can use these channels without causing interference to TV operation and other authorized users, including wireless microphones.

Following a Notice of Inquiry late in 2002, and a 2004 Notice of Proposed Rulemaking, the FCC first adopted rules allowing white space devices in 2006, but left the technical specifics for a later date. Those came in 2008, and then in 2010 the FCC responded to petitions for reconsideration with a number of revisions. Now the FCC has addressed petitions for reconsideration of the 2010 order.

The rules categorize each white space device as either fixed or mobile. A fixed device must have its location either professionally programmed in or determined by an on-board GPS device, and is subject to limits on operating power, antenna height, and antenna gain limits. Before operating, it must query a database of available spectrum for its location. A mobile device may similarly use GPS to determine its location and then query a database (Mode II devices); alternatively, it can contact another white space device that will in turn query the database (Mode I devices). The FCC has so far approved ten private companies to administer the databases, of which two have completed testing to the FCC’s satisfaction.

In its recent order disposing of the petitions for reconsiderations, the Commission provided the following changes and clarifications:

 Antenna Height. The 2010 rules limited fixed device antenna heights to a maximum of 30 meters above ground, and the height above the average terrain (HAAT) to no more than 76 meters. Several parties requested reconsideration of this restriction, particularly the HAAT portion. (According to one, the majority of the state of West Virginia would have been off-limits.) The FCC now allows fixed white space devices to have antennas up to 250 meters above average terrain, although still no more than 30 meters above ground level. At the same time, the FCC revised the separation distances between fixed white space devices and television contours to allow for the greater HAAT, but left unchanged the separations for wireless microphones and the exclusion zones around MVPD, LPTV, and BAS receive sites.  A device that provides database information to Mode I portable devices must comply with the previous HAAT limitations, so as to keep the Mode I device from straying too far from a known location.

Out-of-Band Emissions: The 2010 rules limited out-of-band emissions to 72.8 dB below the device’s highest in-band emissions. Now the out-of-band emissions are relaxed to 72.8 dB below the maximum power allowed within the 6 MHz bandwidth. The new order also cuts back the required occupied bandwidth from 6 MHz to 5.5 MHz, so as to ease the roll-off at the channel edges, and slightly increases the allowable power spectral density so as to leave total power unchanged.

Channel 52 Protection:  As part of the transition to digital television, the FCC auctioned former TV channels 52 and above for wireless use. The wireless companies have long sought restrictions on channel 51 TV operation to protect their frequencies just above, and similarly requested limits on white space devices on channel 51. The FCC refused, partly on procedural grounds, and partly on the principle that white space devices, being unlicensed, are already required to protect licensed wireless operations.

Classes of Devices: The FCC rejected a new class of white space device, similar to “Mode II” but for indoor use only, without GPS capabilities. The FCC feared these could be easily moved without updating their locations, thus creating interference. It also found the new class to be largely unnecessary, as Mode I portable devices may operate without geolocation (although they must query a Mode II or fixed device periodically).

Confidentiality of Database Information: The FCC makes publicly available all information required to be included in the databases that white spaces devices must search before operating.  A cable association asked the FCC to withhold certain data, including coordinates of cable headends and towers, claiming this type of equipment was “critical infrastructure” that could be subject to terrorist attack. The FCC disagreed with the premise and refused the rule change.

Finally, the FCC clarified two points. It emphasized that LPTV, television translator, and Class A television stations will have their receive sites protected based on the coordinates available in the existing CDBS database. The FCC will create a new web interface so that broadcasters can update the information. Second, the recent order corrects the coordinates of certain radio astronomy sites, which must be included in white spaces databases and protected by white spaces devices.

Most of the rule changes will take effect 30 days after publication in the Federal Register. Revisions to the filing of receive site information and entry of other information into the white spaces databases require OMB sign-off, and will probably take a few months longer.   Check back here for updates.

So far all of these rules control only a limited deployment in Wilmington, NC. But with the rules approaching final form, and more databases coming on line, white space devices may finally take the big step from PowerPoint to reality.