CRAIG BIRKMAIER /
04.01.2008
Originally featured on BroadcastEngineering.com
The second time around

In his book, “Defining Vision: The Battle for the Future of Television,” reporter Joel Brinkley tells how the drive for advanced television has its roots in an FCC proposal from the '80s, which required broadcasters to share additional broadcast white spaces with the land mobile industry. In an effort to hang onto their precious frequencies — and inspired by Japanese HDTV experiments — the broadcasters struck a new plan.

They said they needed the underutilized spectrum space for HDTV. Brinkley's book describes the discussion that ensued at that NAB meeting in 1986. An unidentified participant in the meeting reportedly raised a concern, “Yeah, but what if we really get it?”

Wish granted

Ultimately broadcasters did get the opportunity to deliver HDTV to the masses. Rather than using two 6MHz channels, as broadcasters originally proposed, the DTV standard that was adopted by the FCC in 1997 loaned each broadcaster a second channel for the new digital service.

After a simulcast transition period — now scheduled to end Feb. 17, 2009 — broadcasters will return the spectrum used for NTSC broadcasts, and the TV bands will be compacted into channels 2 through 59, freeing up the 700MHz spectrum for new applications.

Auctions of the 700MHz spectrum ended in March. Based on the bidders, this spectrum will be used primarily for wireless telephony and data services, as well as TV broadcasts optimized for mobile and handheld devices.

Broadcasters got two more decades of virtually exclusive use of this beachfront spectrum. Channels 14 through 20 are still shared with land mobile services. Medical telemetry devices share several channels. And wireless microphones used by TV broadcasters and production companies operate in this spectrum. These are typically licensed applications, though many users never apply for those licenses.

So here we are 22 years later, and broadcasters are finally facing the end of the analog TV era. However, the debate over appropriate uses of the white spaces in the compacted broadcast TV spectrum (channels 2 through 59) still rages on.

It's like déjà vu

Several factors have historically contributed to the need for the broadcast white spaces. First and foremost, the use of high-powered TV transmitters on tall transmission towers cause signals from these transmitters to radiate into adjacent TV markets.

This is particularly true for geographic areas with high population density and multiple adjacent markets, such as the northeast corridor between Washington, D.C., and Boston, as well as in Southern California. Many channels cannot be used in adjacent markets because of interference considerations, and this legacy has been perpetuated with the new DTV service.

Second, the RF design of legacy analog TV receivers was limited in the early days of broadcasting. The lack of sensitivity in early TV tuners often required that several adjacent channels not be used to protect the one channel carrying a TV broadcast. Modern TV tuners offer improved sensitivity, as evidenced by the ATSC recommended practice A-74, which details minimum receiver performance guidelines.

And finally, the propagation properties of certain frequencies in the TV bands, and reserved use for other applications, such as radio astronomy (channel 37), require the designation of additional taboo channels.

Let's open up

In 2004, the FCC issued a notice of proposed rulemaking (NPRM) that would open up the white spaces for new uses. The commission proposed to classify unlicensed broadband devices to be used in the TV bands into two general functional categories.

The first category would consist of lower power personal/portable unlicensed devices, such as Wi-Fi cards in laptop computers or wireless in-home LANs. The second category would consist of higher power fixed/access unlicensed devices that are generally operated from a fixed location and may be used to provide a commercial service such as wireless broadband Internet access.

Unlicensed permission

In October 2006, the FCC issued a report and order and further notice of proposed rulemaking (FNPRM) for new uses of the white spaces. (See “Web links” on page 20.) This order authorizes the fixed/access unlicensed devices mentioned above. Service may begin Feb. 18, 2009. After the first NPRM was issued, the IEEE began work on a standard for these fixed point-to-multipoint systems. The IEEE 802.22 standard is currently going through the final phases of documentation and adoption. (See “Web links.”)

The FNPRM extended the opportunity for comments and testing of portable devices that would detect the availability of unused channels allowing their unlicensed use in the TV bands. Two such prototype devices were tested last year with mixed results. A second round of tests are currently underway with four prototypes.

Yea vs. nay

Predictably, the NAB and the MSTV strongly oppose the use of unlicensed portable devices in the TV bands. (See “Web links.”)

Several organizations are pushing for the unlicensed use of the white spaces. The New America Foundation has issued several reports and has filed comments with the FCC in response to the white spaces NPRM. (See “Web links.”) And several influential information technology companies have formed the White Spaces Coalition, promoting the unlicensed use of the white spaces and developing the prototype devices that the FCC is testing. Members of the coalition include Dell, Earthlink, Google, HP, Intel, Microsoft and Samsung.

These organizations counter the assertions of the NAB, the MSTV and other companies that oppose the unlicensed use of the TV bands, claiming that it is imperative that the commission consider the enormous social and economic opportunity costs of accommodating the unnecessarily restrictive (and spectrally inefficient) recommendations of self-interested spectrum incumbents.

Love the one you're with

Obviously the debate over licensed vs. unlicensed uses of our scarce spectrum resources is steeped in history. It also has strong ties to the issue of government protection of the monopolies and oligopolies it has created via regulation of the telecommunications industries.

The breakup of AT&T serves as an excellent backdrop to the white spaces debate. Prior to the breakup of AT&T, the market for telephone devices was a monopoly for AT&T and its manufacturing subsidiaries.

The greatest effect of the breakup came from the regulations that allowed any company to manufacture and sell devices to connect to the telephone systems operated by the seven Baby Bells. This not only caused the price of a telephone to become extremely competitive, it also enabled a period of innovation, bringing a wide range of new telephones and services to market. Perhaps the most relevant parallel to the white spaces debate is the birth and proliferation of wireless telephone handsets using unlicensed spectrum.

The inbreeding of the Baby Bells inevitably led to their getting back together again, after consumers fell in love with cellular phones they can use anywhere. Unfortunately, not only did the Bells renew their matrimonial vows, they managed to create a new oligopoly in the image of Ma Bell.

Today, wireless service is sold with long-term contracts that subsidize wireless phones, which only work with one carrier. Service portability is virtually nonexistent, and the business model offered by all of the cellular carriers is based on controlling everything you do on their networks.

Preventing attachment

Google and others in the IT industry asked the FCC to impose restrictions on some of the 700MHz spectrum that is currently being auctioned. They asked for, and the FCC approved, regulations that allow any device to be attached to the networks that operate in the large C block of the spectrum auction. They also asked for, but did not get, the ability to force the successful bidders for the C block to sell bandwidth on their networks wholesale to potential competitors.

Google put up the performance bonds required to bid in the current spectrum auction. However, it appears that it dropped out of the bidding wars after it was clear that the FCC minimums were met. Apparently, what Google and the other White Space Coalition members really want is the ability to create a new marketplace for unlicensed devices in the TV band white spaces.

Moving targets

To be honest, the real value of the TV bands no longer lies in the ability to deliver TV to fixed receivers in the home. Its value is tightly coupled to legislation and regulations that allow broadcasters to seek compensation for their signals from the multichannel cable and DBS systems. Retransmission consent payments are becoming a significant contributor to bottom-line profits for TV broadcasters.

As a result, it appears that broadcasters are rekindling their romance with devices that use an antenna to pick up their DTV signals. The ATSC is currently evaluating technologies that will support mobile and handheld devices that require a more robust modulation standard than 8-VSB, which was designed and tested using the same methodology used by the FCC for the NTSC standard — an outside antenna on a 30ft mast.

The mobile standard is expected to be finalized this year, with the potential that mobile services could begin after the end of the DTV transition next year. The questions: What will these services be? And how can broadcasters create new revenue streams from them?

What we need

Duplication of the legacy free-to-air TV broadcast model for mobile devices does not appear to be a compelling application. Attempts to create a subscription multichannel service hold great interest among broadcasters, but the cellular phone system operators have had little luck selling subscription TV packages to their customers.

What is needed is a new business model that delivers bits to things that move — not another ISP that provides two-way Internet connectivity, but a system that pushes all kinds of services to mobile devices.

The ability to determine what services are available and to teach devices to capture bits of interest may depend on limited two-way connectivity. If the device is a cell phone or a Wi-Fi connected notebook computer or handheld, that back channel may already exist.

It would be far more desirable, however, to use the white spaces for this back channel. Fixed point-to-multipoint ISPs could provide cheap broadband links to the TV in the family room. Unlicensed portable devices could use the white spaces for the back channel and the mobile standard to deliver services, all in the same TV bands using a common tuner.

Perhaps the time has come for broadcasters to think differently the second time around. Broadcaster support for unlicensed devices that use the white spaces could lead to a whole new consumer love affair with broadcast TV.


Craig Birkmaier is a technology consultant at Pcube Labs.

Web links

Send questions and comments to: craig.birkmaier@penton.com



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