In October, the Federal Communications Commission asked for input on potential uses and technology requirements for high-frequency wireless spectrum in bands above 24 GHz. Most wireless uses today use frequencies below 6 GHz. The FCC set a Jan. 15 deadline for responses, and dozen of organizations laid out insights for suitable uses of the high-frequency bands, some of them general and others very specific.
In addition to futuristic technology scenarios, many companies pressed the FCC to consider high-frequency wireless uses in cooperation with the global technology community and not in a vacuum, so that a common worldwide approach evolves.
Some disagreements have already emerged, including one over whether the FCC should license high frequency spectrum for use by individual network operators or leave such bands unlicensed.
The CTIA, the trade group representing U.S. wireless carriers, urged the FCC to issue exclusive licenses for use of the high frequency spectrum bands "as much as practicable." Google, meanwhile, argued that "the high-frequency bands are especially suitable for shared and unlicensed use."
Higher frequency bands have shorter wavelengths and typically have not been used for many cellular wireless transmissions because they require sending a signal in a straight line (line-of-sight) and don't easily penetrate walls and trees.
However, recent advanced antennas and technologies under development to shape radio waves with hardware and software make it possible to send signals over high frequencies that can reach 200 yards at speeds of up to 10 Gbps, according to several filings. That speed is 1,000 times faster than the typical 10 Mbps downlink on an LTE smartphone today.
That kind of wireless throughput will require cramming many more antennas into smartphones and other handsets, several companies said in their comments to the FCC. But it will also be useful for connecting smart devices to one another, including sensors in cars, along streets and throughout businesses and homes.
There isn't a widely agreed upon definition of 5G or an actual 5G standard. The most ambitious uses include wireless augmented reality, virtual reality, 3D and quick access to a worker's cloud-connected office via wireless. The International Telecommunications Union, an agency of the United Nations, is holding a World Radio Communication Conference in Geneva in November that will help establish international spectrum and technology requirements for 5G for 2020 and beyond.
Hoping to get an early start, the FCC has set Feb. 17 as the deadline for making what it calls "reply" comments in addition to the initial comments that were due Jan. 15. The FCC is actively encouraging reply comments from citizens of all types, not just large companies. Comments can be made by going to the FCC website and clicking on item 14-177 and filling in the short comment form. All comments will be made public.
Google, in its filing, said high-frequency bands could be "useful for offering broadband access via airborne platforms such as high-altitude balloons or unmanned vehicles, where deployment of terrestrial networks is uneconomic." Qualcomm, in its filing, introduced the idea of connecting drones, robots and industrial machines for 5G services "that are not even imaginable today."
Several of the companies have already conducted 5G lab tests. Samsung, in a 94-page filing, said it has already performed a 5G network test with wireless transmissions of 7.5 Gbps, and included a YouTube video link depicting the test from October.
Even though many vendors are talking about 100-to-250 yard range from a handset to an antenna in a cellular configuration, Samsung said it also has conducted a line-of-sight test in the high frequency range covering a distance of about one mile.
Samsung also projected ways that many thousands of wireless base stations in major cities such as New York could be connected to satellites to expand coverage.
Given the number of FCC filings and the wide variety of technologies and uses for high frequency bands given by the vendors, it's difficult to predict how the FCC will respond, said Jack Gold, an analyst at J. Gold Associates. The high frequency bands will also be fertile ground for plenty of competition among equipment and service providers.
"Many new services could come into being if the flexibility is there to allow them without having to go through years of review by a licensing agency," Gold said. Given the physics involved, multiple high frequency band users could operate "very close to each other using the same channel without interference," Gold said. "That significantly expands the amount of bandwidth available."
Gold also predicted that whatever the FCC decides won't be universally shared by other licensing bodies around the globe. This lack of agreement could make things complicated for world travelers who want to take advantage of 5G smartphone capabilities in the U.S., and find those features may not work in other countries.
Gartner analyst Akshay Sharma said that in-building wireless coverage is more difficult with high frequencies, which don't penetrate walls easily. As a result, vendors will need to hand off signals from multiple radios operating in concert as Samsung is doing with trials of 64 antennas on a single device in the 28-GHz band.
Small wall-mounted cellular base stations (often called small cells) inside of buildings can also use higher frequencies, but Sharma said small cells operating at high frequencies that are mounted on lamp posts or the sides of buildings may be better used for mobile backhaul to carry signals to fast fiber-optic connections outdoors.