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How will wireless LAN equipment vendors use freed up TV white spaces?

The TV white spaces spectrum released by the FCC will lead to a new wave of wireless LAN equipment innovation with wireless LAN access points capable of operating in traditional Wi-FI frequencies as well as the new low-frequency white space spectrum, delivering long-range networking options to enterprises.

The FCC's decision to open up the so-called TV white spaces spectrum will spawn a new crop of enterprise wireless LAN products that use the unlicensed radio frequencies to enhance campus wireless LANs and enable affordable wireless metro area networks.

The FCC recently approved the public unlicensed use of the TV white spaces spectrum, a set of radio frequencies left open by the television industry's transition from analog to digital transmission. The 300 to 400 MHz of spectrum has low-frequency characteristics that offer distinct advantages over the 2.4 GHz and 5 GHz bands currently used in Wi-Fi technologies, including the ability to transmit more effectively through solid objects and send signals over longer distances.


Although the TV white spaces spectrum offers longer range transmission than existing Wi-FI spectrums, throughput of the new spectrum will remain on par with what 802.11n technology currently provides.

"There are already various experimental projects going on," said Greg Ennis, technical director of the Wi-Fi Alliance, the industry consortium that certifies Wi-Fi products for interoperability and ensures fidelity to standards. The IEEE 802.11af task group is already hashing out standard protocols for TV white spaces spectrum use and the Wi-Fi Alliance has a task group in place to start developing a certification program for products. The target ratification date for 802.11af is December 2011 but Ennis said that date might slip into the first half of 2012.

Wireless LAN access points will evolve with TV white spaces spectrum

Wireless LAN equipment vendors will likely develop access points with the capability to transmit both the current Wi-Fi bands (2.4 and 5 GHz) as well as the new TV white spaces spectrum, enabling them to reach longer range and penetrate more structures, Ennis said.

"Wi-Fi equipment can actually transmit at a variety of different data rates using a variety of different modulation techniques. Essentially the devices adjust themselves to the distance that they're trying to communicate and the airwave characteristics in the area in order to operate at the best modulation and data rate for the most robust signal in that situation," Ennis said.

So future laptops, smartphones and other Wi-Fi-enabled devices will be able to shift from the 2.4 and 5 GHz spectrum to the TV white spaces spectrum dynamically as users move about. Enterprises that have large campus networks will take advantage of the long range nature of TV white spaces.

Consider a hospital that has various medical diagnostic devices on Wi-Fi enabled carts in an asset tracking system. If a cart is accidentally locked in a basement room with poor Wi-Fi service in the 2.4 and 5 GHz bands, the signal from that cart could penetrate the thick floors and walls of the building and travel to a distant access point by automatically operating in the TV white spaces spectrum.

TV white spaces spectrum for backhaul within campus networks

Wireless backhaul will probably be the first class of enterprise products using the TV white space spectrum, according to Keerti Melkote, founder and CTO of Aruba Networks.

Enterprises that connect buildings with a service provider's wireline metro area connection, an expensive dark fibre connection or a microwave backhaul will instead be able to use specialized access points transmitting in the TV white spaces spectrum. This will offer enterprises tremendous early savings for backhauling large, multi-building campus networks.

TV white spaces for metro area networks and smart grids

Even with all of the enterprise potential, service providers may be the first to benefit from access to TV white spaces spectrum, Melkotte said. The spectrum's long-distance capability will allow service providers to build out lower-cost metro area networks using Wi-Fi technology. Mobile carriers will use these networks to offload data traffic from their cellular networks. In turn, enterprises will have the option to buy laptops and smartphones with the ability to communicate in the TV white spaces spectrum, allowing users to connect to metro area networks as easily as they connect to Wi-Fi hot spots.

And given the FCC's geolocation requirements, carriers, enterprises, consumers and equipment vendors should be able to share this unlicensed spectrum without conflict. All devices that use the TV white spaces spectrum will use a geolocation device, such as GPS, to share their location with a national database of TV white spaces devices. They will crosscheck their location to ensure that they aren't conflicting with any other nearby devices. Given the size of the white spaces spectrum, devices in conflict with each other can easily switch channels in order to coexist.

Smart grid vendors will also make extensive use of the TV white spaces spectrum, Melkotte said. Vendors will ultimately design smart meters for utility companies that can transmit in the white spaces spectrum. As a result, utilities will be able deploy smart grids using fewer access points and without necessarily relying on service providers to supply connectivity.

White spaces spectrum product timeline and pricing

It's not likely that the Wi-Fi Alliance will certify pre-standard technology as it did with 802.11n and other Wi-Fi technologies in the past, though that's not completely ruled out, Ennis said.

As for pricing, the volume of uptake will determine the ultimate cost of the new technology. It all boils down to economies of scale, Ennis said. For now, vendors will slowly incorporate white spaces capabilities into their access points. Given that TV white spaces technology will see adoption in wide area networks as well, the market could be huge.

Let us know what you think about the story; email: Shamus McGillicuddy, News Editor

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