The FCC voted to make 100 MHz of spectrum in the 5 GHz band available for unlicensed Wi-Fi use, giving a major shot in the arm to carriers and MSOs looking to push more data traffic to Wi-Fi.

The FCC voted 5-0 to adopt a First Report and Order that makes 100 MHz of the 5 GHz UNII-1 band "more useful for consumers and businesses, and reduce the potential for harmful interference to certain incumbent operations." At issue is the 5150-5250 MHz portion of the Unlicensed National Information Infrastructure (UNII) band, whose unlicensed use was restricted to lower wattage and indoor operations.

The order eliminates a rule that had prohibited outdoor operations in the band and also increases allowable power levels in the band. However, the FCC staff said that the order also protects incumbent users, most notably mobile satellite service, by placing technical limits on the amount of energy that can be directed up toward satellites. As another measure to protect incumbent users, the FCC is going to require companies to notify the commission if they are deploying more than 1,000 access points in the UNII-1 band.

After prodding from Congress and in conjunction with the National Telecommunication and Information Administration, the FCC had already explored wider use of Wi-Fi in the 5.35-5.47 GHz and 5.85-5.925 GHz bands. However, the FCC is now expanding Wi-Fi in the lower portion of the 5 GHz band, namely 5.15-5.25 GHz, using the 802.11ac standard.

In July 2013, the Department of Defense said the Pentagon does not need access to the 5.15-5.25 GHz band for telemetry, and acknowledged it could be made available for Wi-Fi use.

FCC Commissioner Jessica Rosenworcel praised the move and unlicensed wireless in general. Earlier this month she pushed for unlicensed spectrum in a speech before the WiFiForward coalition, a group of wireless and technology companies that are calling for more spectrum for Wi-Fi. Members of the new coalition include the Arris Group, Best Buy, Comcast, the Consumer Electronics Association, Google (NASDAQ:GOOG), Microsoft (NASDAQ:MSFT), Time Warner Cable, the National Cable & Telecommunications Association and others.

As the WiFiForward group notes, more and more traffic is expected to be offloaded from macro cellular networks to Wi-Fi networks in the years ahead. According to Cisco's latest Visual Networking Index Global Mobile Data Traffic Forecast report, 52 percent of global mobile traffic will be offloaded onto Wi-Fi and/or small cell networks by 2018, up from 45 percent in 2013.

Rosenworcel said freeing more spectrum for unlicensed use would create more opportunities for innovators. "This change is going to have real impact because we are doubling the unlicensed bandwidth in the 5 GHz band virtually overnight," she said at the FCC's open commission meeting.

FCC Chairman Tom Wheeler likened the move to turning "trash into treasure."

In a statement, the WiFiForward group praised the FCC "for crafting a thoughtful balance between the needs of incumbents and innovators to make sharing possible. The FCC's action will create a new environment for experimentation, new business models, and better Wi-Fi. The Commission's move today is an important achievement, and a good model for the work that the FCC and the technology community must do in other portions of the 5 GHz band and beyond to support the unlicensed economy."