Transcript
Copyright Lighting&Sound America September 2008 www.lightingandsoundamerica.com
TECHNICAL FOCUS: SOUND
The Trouble with White Space By: Mel Lambert
How a new government policy could alter the future of wireless technology in the performing arts—and not for the better Imminent RF changes being considered by the Federal Communications Commissions, following the transition to all-digital broadcasting, are going to have a profound impact on the performing arts, especially the availability of wireless frequencies used routinely for microphones, body packs, PLs, and intercoms. The new policy will remove not only an upper frequency band, but also make the use of the so-called White Space allocations a catch-as-catch-can process. Also affected are a wide range of broadcast operations that use wireless-based systems and communications devices during in-studio and remote productions, particularly large-scale sporting events.
On February 17, 2009, over-the-air analog TV within the United States will end, to be replaced with higher-efficiency digital transmissions, or DTV. A number of the channels currently being used for analog transmission will be re-allocated for other services. Two main factors affect this RF spectrum: an optimal frequency range currently being used by wireless microphones and related devices. The first is the so-called Digital Dividend, comprising the UHF frequency band between 698 and 806 MHz— Channels 52-69—which has been auctioned off to private companies, reserving a small segment for emergency use. While unused frequencies within this UHF band will remain available to wireless products, their future is uncertain. The second region is referred to as White Space, comprising discrete UHF frequency gaps below 698MHz— Channels 2-51—between the new DTV stations. While these frequency slices currently are not being auctioned or sold, September 2008 • Lighting&Sound America
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Why it’s happening
Congress might consider making them available for such applications as broadband, PDAs, cell phones, Wi-Fi networking systems, intercoms, and so on. And even though such devices represent a potential source of interference for wireless products used in live audio production, newsrooms,
allowed to operate in these White Space areas, possibly affecting digital TV signals, a major concern for terrestrial DTV broadcasters. A number of firms, including Microsoft, Dell, HP, Palm, Google, Philips, and TDK, have asked the FCC, the U.S. government agency responsible or licensing and regulating the RF spectrum, to authorize the use of unlicensed devices within White Space. (While the majority of spectrum space is licensed through auctions that generate large dollar revenues for the federal
Red bars indicate White Spaces that are currently safe areas for operation of wireless microphones.
sporting events, boardrooms, and other applications, several solutions are being proposed. The most exciting is that new consumer and commercial devices would have to automatically look for the presence of professional products using frequencies within that band, and avoid interfering with their operation. A major stumbling block has been that the majority of wireless operations are unlicensed, meaning that the FCC can hardly suggest that other users in a target frequency band desist from causing potential interference. Following the DTV transition, it is possible—even probable—that a variety of unlicensed consumer devices, as well as proposed Wi-Fi broadband services, may be
government, many organizations make a strong argument for an unlicensed model, claiming that the money otherwise used on licenses can be better invested in technical innovation.) The main opposition to the use of White Space for broadband comes from TV broadcasters, who, not unreasonably, are concerned that the use of such frequencies would create interference, and maybe hamper the transition to DTV. Although initial tests by the FCC’s Office of Engineering and Technology/OET of non-invasive systems for use within the White Space spectrum were unsuccessful, in late August the Commission put these prototype devices through another round of tests.
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In March, Google urged the FCC to allow White Space to be used for nationwide wireless Internet access. “The unique qualities of the TV White Space— unused spectrum, large amounts of bandwidth, and excellent propagation characteristics—offer a once-in-a-lifetime opportunity to provide ubiquitous wireless broadband access to all Americans,” wrote Richard Whitt, Google’s Washington telecom and media counsel, in a letter to the FCC. (It didn’t go unnoticed that Google fared badly in the FCC’s Digital Dividend auction, with the major frequencies going to Verizon Wireless and AT&T.) And the U.S. legislature has also
to TV stations. (Kerry introduced the same bill in the 109th Congress, but it was not acted on by the full Senate.) Separately, New Hampshire Senator John Sununu introduced the White Spaces Act of 2007 (S. 337), which would open White Space within 90 days of passage, or October 1, 2008, whichever comes first. This bill also considers the option of auctioning licenses for the spectrum. Contrary to such trends, Congressman Bobby Rush of Illinois introduced Interference Protection for Existing Television Band Devices Act of 2007 (H.R. 1320), which would require manufacturers of unlicensed devices to
causing interference to current users of the TV spectrum, including wireless microphones. Several solutions have been proposed, including Listen Before Talk, to check for existing RF traffic prior to transmitting; Geolocation/Database, or using a GPS receiver to check for broadcast-license assignments; and Local Beacon, or reception of a locally transmitted signal that identifies which TV channels may be used in the local area. (Many industry insiders consider that White Space legislation and such solutions will involve ongoing discussions between interested and impacted parties, and pass through multiple revisions prior to any bills being enacted.)
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Viable technology for White Space operation
White Space exists in areas where DTV frequencies do not overlap, and are safe areas for wireless mics.
gotten in on the act. In an effort to accelerate the availability of broadband services—the proposed date to allow unlicensed devices to use White Space is February 17, 2009—Massachusetts Senator John Kerry introduced the Wireless Innovation Act of 2007 (S. 234), which directed the FCC to free up White Space frequencies within 180 days of enactment; a version of this bill has also been introduced in the House of Representatives (H.R. 1597) by Representative Jay Inslee of Washington. As the bill pointed out, in many markets, fewer than 50% of the available broadcast channels have been licensed September 2008 • Lighting&Sound America
demonstrate that products do not interfere with existing devices, such as wireless mics and monitoring systems. Interestingly, the bill also seeks to halt the deployment of fixed wireless devices, such as broadband services, to rural areas, until the DTV transition is complete. (The bill is asking that new portable devices not be allowed to use White Spaces until fixed devices have been operating for three years without causing interference.) The FCC and others remain adamant that adequate time be allowed to develop solutions that will permit unlicensed devices to operate without
The main problem, however, is that current R&D has not produced a foolproof technology. As Dennis Wharton, EVP of the National Association of Broadcasters/NAB, commented in response to the FCC’s action: “NAB has no quarrel with field tests. But, based upon multiple failures of unlicensed devices in laboratory testing thus far, we remain highly skeptical that this technology will ever work as advertised.” The association has lined up a number of heavy-hitter legislators on Capitol Hill to cast doubts on such unlicensed devices. The NAB is not alone in this debate. The Association of Maximum Service Television’s president, David Donovan, has a reputation as a stern critic of unlicensed devices. “We appreciate the commission’s efforts to continue testing these proposed unlicensed devices,” he commented in late spring. “Given their failure in the lab, it is important they undergo extensive and thorough testing. The risk of interference to consumers’ reception of free, over-the-air digital television is enormous. First, sensing does not work—it failed repeatedly in the lab. To suggest that sensing provides any form of protection for TV viewers is simply not credible. Moreover, none of the devices submitted to the FCC sensed wireless microphones. None!” Also casting their hats into the ring are a number of trade organizations,
including POLCOMM2008, the organization that coordinates wirelessmicrophone frequencies during Democratic and Republican National Conventions. Louis Libin, POLCOMM2008 chairman and president of Broad-Comm, offers that “these conventions would provide a perfect opportunity to conduct further testing regarding the efficacy of [such] devices…during an event that employs hundreds of wireless microphones and frequencies.” Daryl Friedman, vice president of advocacy and government relations for The Recording Academy (NARAS) says, “The commission should move with extreme caution before approving any new portable device operations in the TV band. We would be happy to help coordinate an FCC visit to the Lollapalooza Festival in Chicago on August 1.” And Don Lepore, producers of NBC’s Nashville Star, has invited the OET to visit The Music City: “To put it in its simplest form, the perception that there is significant fallow White Space in cities like Nashville is just wrong.” “We appreciate the commission’s efforts to continue testing these proposed unlicensed devices,” offers Donovan. “Given their failure in the lab, it is important that [such devices] undergo extensive and thorough testing. The risk of interference to consumers’ reception of free, over-the-air [DTV] is enormous.” The Wireless Innovation Alliance/WIA is adopting a different spin. “White Space technology works and, as a result, the FCC continues to move the process forward,” considers WIA spokesman Jake Ward. “The alliance includes computer companies pushing the FCC to allow the [use of such] devices. Given the extensive information gathered by the FCC, as well as the work done by the FCC, we expect the [commission] to move forward with their final order immediately after this round of testing,” he added.
The impact on live performance In the trenches, particularly among members of the Broadway community, there is consternation that the spectrum changes will dramatically impact the use
of wireless microphones, PLs, and IEM systems. “We are planning to use 70-80 RF channels for our Christmas productions,” explains Dan Gerhard, sound designer for a number of productions at New York’s Radio City
shows must coordinate with each other. We behave as good neighbors; they know what we use and we know what they use.” Sound Associates, based in Yonkers, New York, with offices in New York City
Mark Brunner: “Neither the beacon plan proposed by Google, nor the one submitted by Motorola, will provide solid protection for wireless microphone users. “These unacceptable proposals would pull the plug on wireless microphone users everywhere.”
Music Hall. “These are going to be difficult to replace. We are considering frequency-agile systems that can move around the spectrum looking for free channels.” For the planned Christmas show, Gehard will use 60-70 wireless mics, in addition to 12 IEMs and 12 PLs. And its location, close to UniversalNBC’s corporate headquarters at Rockefeller Center, poses challenges for Radio City Music Hall, says Tom Arrigoni, head audio engineer. “Frequency coordination with NBC is extremely important for us, just like the Broadway
and Atlanta, supplies a large number of wireless systems to the theatre and musicperformance communities. Sound Associates’ CEO, T. Richard Fitzgerald, also serves as technical advisor to the Microphone Interest Coalition/MIC, an industry pressure group. He considers Google’s proposal that White Space be used for nationwide Wi-Fi access to be far from a compromise, and should not be viewed as a solution for wireless microphones. “Google seems to suggest that microphone users should be grateful for such a generous offer,” he considers.
White Space Devices Fail Again As we go to press, this is the latest information, from ESTA’s Standards Watch: “The FCC tested prototypes of white space devices at the NFL pre-season game between the Washington Redskins and Buffalo Bills at Washington’s FedEx Field on August 9. Shure has issued a press release in which Mark Brunner, Shure's senior director, public and industry relations, says, ‘The FCC’s tests of prototype white space devices at FedEx field prior to Saturday’s game between the Redskins and the Bills conclusively show that spectrum sensing white space devices will cause harmful interference to wireless microphones during live events. Simply stated, the prototype devices were unable to consistently identify operating wireless microphones or distinguish occupied from unoccupied TV channels.’” “Motorola claims its geolocation-based technology works well for avoiding interference with existing spectrum holders, but the technology cannot avoid interfering with wireless microphones working in the TV broadcast band. The geolocation-based technology works by consulting a database that lists what licensed broadcasters are using what frequencies in what geographical areas. This, of course, does not work for identifying unlicensed, mobile RF devices such as wireless microphones.”
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“But the proposal…is pretty much like offering a starving man a few crumbs and a drawing of a sandwich.” Google’s proposal—similar to one submitted by Motorola—requires wireless microphone users to operate a “beacon” transmitter that White Space devices would monitor in order to prevent them from interfering with wireless transmissions. Google’s proposal also identifies a “safe harbor” of three DTV channels—36, 37, and 38—in which wireless devices can function without interference from White Space systems. (Other protections currently under evaluation by the FCC’s laboratory include
consumer devices and wireless technologies—even with safeguards— will create havoc for users and audiences of RF-based systems microphones; the company is urging the FCC to remain undistracted by efforts from Microsoft, Google, Motorola, and others to downplay the role of continued technical testing, particularly spectrum sensing. “Neither the beacon plan proposed by Google, nor the one submitted by Motorola, will provide solid protection for wireless microphone users,” states Mark Brunner, the firm’s senior director, global public relations. “These unacceptable
clock is ticking. “FCC Chairman [Kevin J.] Martin’s term ends with this current legislature. So, if we are to secure our RF spectrum space, we need to act quickly to lobby the FCC to make sure that the [Google and Motorola] proposals for beacon technology include a reliable, proven spectrum-sensing, which, to date, hasn’t been seen to work. We need to ensure that the FCC tests proposed White Space systems, both in the laboratory and the real world, and develops a viable solution. Otherwise, we face major headaches [while using wireless systems].”
Richard Fitzgerald: “If we are to secure our RF spectrum space, we need to act quickly to lobby the FCC to make sure that the [Google and Motorola] proposals for beacon technology include a reliable, proven spectrum-sensing, which, to date, hasn’t been seen to work. We need to ensure that the FCC tests proposed White Space systems both in the laboratory and the real world, and develops a viable solution. Otherwise, we face major headaches.”
intelligent spectrum-sensing technology embedded in portable devices.) MIC considers the safe harbor proposal to be seriously flawed, since Channel 37 is reserved for medical telemetry and radio astronomy use, while, in many cities, Channels 36 and 38 are being utilized by DTV stations. It also states that two channels of spectrum space will prove inadequate for a large theatrical or sporting production’s wireless needs. The coalition is not alone in its analysis. The wireless microphone manufacturer Shure Inc. considers that trying to use White Space for both
proposals would pull the plug on wireless microphone users everywhere.” In a recent FCC filing, Shure asserts that Motorola would have the FCC believe that its combined geo-location, disabling beacon, and spectrum-sensing plan “is a comprehensive approach” that would protect White Space incumbents like wireless microphone users. “But that couldn’t be further from the truth,” Brunner says. “None of these approaches is a practical or currently technically feasible solution to reliably protect wireless microphone users from damaging interference.” Fitzgerald is also concerned that the
As the sidebars attached to the article indicates, this is still very much a story in progress. We’ll revisit the issue in about six months to see what progress—if any—has been made.
Mel Lambert has been intimately involved with production industries on both sides of the Atlantic for more years than he cares to remember. He is now principal of Media&Marketing, a Los Angeles-based consulting service for the professional audio industry, and can be reached at
[email protected] or +1/818.753-9510.
Two Alternatives—Ultra-Wideband and STL Wireless Microphones At least one microphone manufacturer has developed a viable alternative. Audio-Technica recently introduced its SpectraPulse Ultra-Wideband wireless-microphone system that utilizes up to 14 simultaneous channels without RF competition, frequency hunting/coordination or infringing upon White Space issues. SpectraPulse is said to represent the first commercial sound implementation of UWB technology, which was recently licensed for commercial use by the FCC. Also, Sennheiser’s Evolution 3000/5000 Series wireless mics can be retuned to the exact frequency a user might need, and are available for operation in the STL 944-952 MHz band, a range unaffected by the DTV conversion.
September 2008 • Lighting&Sound America
