Spectrum is like oil – a non-renewable, natural resource with a price that reflects its perceived scarcity. Hence the interest in "white spaces" (WS), which are the spectral equivalent of fracking and oil sands: The easy sources have been tapped, and now the technology, scarcity and market have reached the point where it makes sense to go after the difficult ones.

The TV bands are home to the best-known example of WS mining, but it's a mistake to assume that the WS market opportunity begins and ends there. That's one key finding in the new Heavy Reading 4G/LTE Insider, "TV White Space Spectrum for LTE: It's Free, but Not Cheap." In fact, for many of the vendors developing WS products, TVWS is a stepping stone to other WS markets.

One example is using TVWS technologies to enable Long Term Evolution self-organizing networks (LTE SON). Another example is using TVWS database technologies to shoehorn new commercial services alongside incumbent U.S. government users. "When you see companies like BAE, Rockwell Collins and Lockheed Martin interested in database-enabling technologies, it tells us that opportunities for the sharing of government spectrum are also driving that," says Mark Gibson, Comsearch director of business development.

It makes sense for those vendors to hedge their bets, because the market for TVWS is anything but certain. One reason is that in some applications TVWS will compete with cellular, Wi-Fi and DSL. Incumbency has its privileges, such as a big, global installed base and a big head start down the cost curve. On the plus side, some TVWS vendors say that the prices of their early base station and customer premises equipment (CPE) product runs are already competitive with established products such as Canopy. That should help them target wireless Internet service providers (WISPs), which could turn out to be one of the biggest TVWS opportunities.

In the cellular market, another challenge is operator mindsets. Huawei Technologies Co. Ltd. and InterDigital Inc. (Nasdaq: IDCC) are among a handful of vendors developing TVWS products that use LTE or Wi-Fi as the air interface. This design would enable operators to use TVWS spectrum with LTE-Advanced's carrier-aggregation feature. For example, an operator could combine one or more carriers from cellular spectrum and one or more from TVWS spectrum to deliver the amount of bandwidth that a particular application needs.

The catch is that many cellular operators are still deeply reluctant to 1) use an unlicensed technology to deliver service, even those that already use Wi-Fi offload, and 2) share spectrum with other users that have just as much right, or even more so, to be there. Positive experiences with Wi-Fi offload could make those skeptics receptive to using TVWS for aggregation, offload or both.

Although TVWS typically is perceived as primarily a rural solution, there are potential opportunities in urban and suburban areas, too. For example, TVWS hardware could turn out to be less expensive than the labor and materials for the wired link between the pedestal or pole and the residence – about $600 per home in the case of Verizon's FiOS, for example. "You will see this a way to provide middle-mile and last-mile connectivity," says John Malyar, chief architect for the TVWS database solution at Telcordia Technologies Inc.

The prospect of using TVWS as an access technology for cable, fiber and DSL is also an example of why just about everyone in telecom should keep an eye on this field. Sure, it's nascent and faces multiple hurdles to get to mainstream adoption. But there are already enough telecom giants and household names – Huawei, Google (Nasdaq: GOOG), Microsoft Corp. (Nasdaq: MSFT) and Telcordia – developing TVWS products to give it a decent shot.

And even if TVWS turns out to be a flash in the pan, it's still worth following today for its potential tomorrow in other applications, such as government spectrum. As long as there's a spectrum shortage – in other words, pretty much forever – there will be a market for technologies that promise to free up frequencies once considered too difficult to tap.

— Tim Kridel, Contributing Analyst, 4G/LTE Insider

This report,"TV White Space Spectrum for LTE: It's Free, but Not Cheap," is available as part of an annual subscription (6 issues per year) to Heavy Reading 4G/LTE Insider, priced at $1,595. Individual reports are available for $900. To subscribe, please visit: www.heavyreading.com/4glte.