Wi-Fi operates in two unlicensed frequency bands: the 2.4 gigahertz (GHz) band and the 5 GHz band:
- The 2.4 GHz band is divided into between 11 and 14 channels. Because the entire band is only 79 megahertz (MHz) in width, there are only three non-overlapping channels.
- The 5 GHz band has up to 23 non-overlapping, 20-MHz channels, with different regulatory domains supporting a different number of channels. The FCC domains supports the maximum number of channels.
Currently, the vast majority of Wi-Fi usage is in the 2.4 GHz band; the 5 GHz band remains relatively uncluttered. But the latest Wi-Fi technology, 802.11ac, operates only in the 5 GHz band and use wider channels to boost data transmission speeds. That may be one of the reasons why Federal Communications Commission (FCC) chairman Julius Genachowski has announced plans to free up 195 MHz of wireless spectrum in the 5 GHz band to help increase Wi-Fi speeds and alleviate congestion in high-traffic areas. The new spectrum allocation is the largest block of unlicensed spectrum that has been made available for Wi-Fi expansion since 2003, and is expected to increase Wi-Fi capacity by at least 35 percent.
Some lawmakers have argued that increasing unlicensed spectrum is a waste of resources. They would rather see the government auction off as much spectrum as possible so that it can use the proceeds to help pay off the national debt or fill budget deficits.
In addition to this announcement, the FCC has taken steps in recent years to unleash the potential of next generation unlicensed spectrum, which will reside in lower frequencies than existing Wi-Fi. This enables wireless communications to travel longer distances, better penetrate barriers like walls and buildings, and provide improved coverage over hilly terrain.