"Super Wi-Fi" Arrives In The U.S.
By Paul Kruczkowski, Editor
The first “Super Wi-Fi” network went live in Wilmington, NC, last Thursday, becoming the first FCC-approved network to use unlicensed “white spaces" between broadcast TV frequencies in the UHF and VHF bands. If approval for such networks expands nationwide, as expected, it would represent the most significant introduction of unlicensed spectrum in the U.S. since the FCC permitted transmission in the ISM bands in 1985. When the ISM spectrum was made available, RF designers gave us innovations like DECT cordless phones, baby monitors, Bluetooth, RFID, smart utility meters, ZigBee, and today’s 2.4 GHz Wi-Fi. The availability of white spaces spectrum could provide the RF design community with similar opportunities for growth and innovation. But what exactly is “Super Wi-Fi” technology? How did it come to be? And where is it headed?
This new network technology, dubbed “Super Wi-Fi” by FCC Chairman Julius Genachowski, is not Wi-Fi at all. It is actually a wireless regional area network (WRAN) technology defined by IEEE 802.22 and based on cognitive radio technology, where two-way radios adapt to network conditions to use spectrum efficiently and to avoid interfering with other licensed or unlicensed users. This approach enables sharing of the unused spectrum between broadcast TV channels while not interfering with TV broadcasters in a given area. White spaces networks offer longer range — measured in miles instead of feet — and its lower frequencies are able to penetrate vegetation and buildings and traverse rough terrain, unlike today’s 2.4 GHz Wi-Fi. The need for more unlicensed spectrum and the limitations of current wireless networks have fueled the development of white spaces network technology.
The FCC approved the unlicensed use of white spaces on November 4, 2008, and much like the opening of the ISM band in 1985, the white spaces decision stimulated a great deal of investment and innovation. In early 2009, a group of companies including Microsoft, Google, Dell, HP, Intel, Philips, Earthlink, and Samsung formed the White Spaces Coalition, with the common goal of providing high-speed Internet access to U. S. customers by gaining FCC approval for devices using white space. The FCC finalized its rules for the unlicensed use of white spaces in Memorandum Opinion and Order FCC 10-174 on September 23, 2010, providing specific requirements for developers to move forward with network equipment and trails.
The FCC order required authorized radios operating in white spaces to report their location to an authorized TV band database system, which would then return a list of authorized channels in the area, to prevent interference with licensed broadcast TV stations. Spectrum Bridge Inc. (SBI), a software company focused on spectrum management, developed a white spaces TV band database system and was also an important member of the Wireless Innovation Alliance (WIA) coalition, whose members deployed several trial white spaces networks. These trial networks covered applications including broadband wireless internet connectivity, public safety and video surveillance, control and monitoring of utilities, and smart grids.
On December 22, 2011, the FCC approved both the first white spaces radio and SBI’s TV database system, paving the way for Wilmington to launch the first approved TV white spaces network in the United States last week. Wilmington is now the proving ground for the first generation of radios and devices developed for white spaces frequencies. The city is currently demonstrating the network’s capabilities by providing broadband wireless Internet access at a city park and by monitoring a city garden with wireless security cameras, and it expects to expand those capabilities to public lighting, water quality monitors, and river water sensors in the future.
Additional white spaces networks are planned across the country. One anticipated application is to deliver “last-mile” broadband internet service to rural communities with low-density populations, many of which still rely on dialup Internet service. Even when fiber optic lines bring signal to rural communities, they often don’t reach out to remote individual homes or businesses. While rural terrain such as mountains, valleys, and dense vegetation render line-of-sight wireless solutions ineffective, white spaces network frequencies propagate longer distances, penetrate vegetation and buildings, and are less affected by rough terrain.
Now that white spaces networking is a reality in Wilmington, the economic incentive to develop approved devices for this spectrum is greater than ever. New concepts and technologies will emerge in white spaces radio design, as several companies have applied or plan to apply for FCC approval this year. Technology companies will continue to develop new chipsets to enable white spaces capabilities for industrial controllers, laptops, notebooks, and smartphones over the next year or two.
High demand for new spectrum should provide enough incentive to drive progress in white spaces networking. Advancing technology should resolve most of the technical issues that will be observed in early deployments. (For instance, initial network speeds may only be in the 1.5 to 3.1 Mb/s range, which is comparable to today’s 3G speeds but much slower than the 80 Mb/s expected by the White Space Coalition.) It may not be Wi-Fi, but I still see a bright future for white spaces.
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