Are higher frequencies mobile's next frontier? The FCC wants to know

Some mobile researchers think future networks will reach into higher frequencies to keep up with traffic, and the FCC now wants to know how it might help to make that possible.

Most of the world’s cellular networks send calls and data traffic over frequencies below 6GHz. Growing demand is expected to put the squeeze on those spectrum bands in a few years, and one way out may be to start using largely untapped frequencies in so-called millimeter-wave bands. Though experts say most of those bands are still lightly used, unleashing smartphones and other mobile devices on them would require some regulatory changes.

To get ahead of that game, on Oct. 17 the U.S. Federal Communications Commission announced a Notice of Inquiry to ask what new high-frequency mobile technology might achieve and which bands might be best to use. New advances could make millimeter-wave radios part of 5G, the next generation of mobile communications, the FCC said in a news release. That generation is expected to reach the real world around 2020.

The agency wants input on frequencies above 24GHz, of which there are several being studied for mobile services. At a conference in April in New York, researchers discussed the use of various bands between 28GHz and 72GHz. Within that range, some frequencies are used today for applications such as targeted microwave links over rivers and other obstacles. One part of the 60GHz band is open to unlicensed uses such as WiGig and WirelessHD for fast in-room wireless. Some other countries, including China and South Korea, are already looking at using millimeter-wave bands for mobile.

Until recently, very high frequencies were considered useless for mobile because they couldn’t reach far enough or penetrate obstacles such as walls. But recent advances in antenna technology and computing power give millimeter-wave connections greater range, especially in dense urban environments. A team from New York University says it has sent millimeter-wave signals 200 meters on New York streets. That’s within the range at which some mobile operators are expected to place small cells to add capacity for urban users.

The FCC’s notice asks questions about technological developments, about the suitability of various high-frequency bands for mobile use, and about how those bands might be regulated for licensed or unlicensed use. Comments can be filed until Dec. 16, with a reply period following until Jan. 15.