Millimeter wave researchers praise FCC's move to unleash more spectrum at higher bands

While not everyone got what they wished for in the FCC's proposed new rules for new high-band spectrum above 24 GHz, folks in the millimeter wave tech community are happy to see the U.S. move forward in laying the foundation for 5G wireless technology innovations.


The FCC is proposing new rules for four different bands of high-band spectrum above 24 GHz designed to lay the foundation for 5G networks in the U.S. The specific bands that will be studied include the 27.5 to 28.35 GHz, also known as the 28 GHz band; the 37 to 38.6 GHz band, also known as the 37 GHz band; from 38.6 to 40 GHz, known as the 39 GHz band; and the 64-71 GHz band.

Ted Rappaport, director of NYU Wireless, which has conducted pioneering measurements and channel model research at 28 GHz, 38 GHz, 60 GHz and 73 GHz, said he's pleased the FCC has made a move and made a move this quickly. NYU Wireless had lobbied for action via filings with the FCC, warning that in the global race to 5G, the U.S. was falling behind other nations in R&D aimed at the mainstream wireless technology sector. It called for timely action by the FCC to make mmWave spectrum available for commercial use.

While it would have been nice to have more bands allocated, particularly above 71 GHz, "I think this is a great start for 5G, and the fact that we have more unlicensed spectrum combined with more licensed spectrum for 28 and 37 and 39 GHz is great for the country," Rappaport told FierceWirelessTech.

Many people didn't believe the higher spectrum would ever be viable for mobile communications, yet NYU Wireless has been focused on millimeter wave research the last few years, proving to the world that it will work. Rappaport himself has been involved in millimeter wave technology research for two decades.

The FCC's ruling will benefit the worldwide wireless industry by letting people know -- a month before the ITU World Radiocommunication Conference meeting in Geneva -- that there will be massive bandwidth available at these frequencies soon in the United States, which is a big advantage for those who are planning their long-term spectrum investment and capital expenditures, not just for wireless but also for fiber and backhaul, according Rappaport.

Both Commissioners Ajit Pai and Michael O'Rielly said they wished the FCC had included more bands in the item, as they had proposed. Pai said he suggested "including 12,500 MHz of spectrum in the 24 GHz band, 32 GHz band, 42 GHz band and the 70 and 80 GHz bands. Unfortunately, the votes were not there, and the Notice does not propose moving forward on them. The Commission's decision to sit on literally thousands of megahertz of spectrum that could very well be used for licensed and unlicensed innovation is a lost opportunity. The Notice offers no persuasive reason for leaving these bands on the cutting room floor." Pai also said "we don't know which millimeter wave bands will prove to be viable homes for 5G or other wireless uses." 

Like Commissioner Pai, Rappaport would have liked to have seen the commission be bolder about the spectrum above 71 GHz, but "this is a great start," he said.

For mobile operators, the FCC's order should motivate them to gain access to fiber to the last mile because they now know that the wireless pipes are going to be much wider than today's cellular in the last few hundred meters of coverage, as that's what millimeter wave wireless will do. It will have somewhat shorter range in urban settings, but it will have much wider bandwidth, so carriers need to extend their networks closer to the last mile, he said.

Carriers generally get wider bandwidths as they go up in frequencies, and the new ruling could potentially provide channel bandwidths up to 200 MHz or more. Wider channel bandwidths mean higher data rates to the consumer.

Rappaport said millimeter wave frequencies will be more efficient because the antenna will be designed to be much more focused than it is today. That is, "you can think of beams of energy that only go in particular directions, and they'll avoid the kind of omnidirectional interference that we have in today's cell phone. We'll be able to get much better interference control," he said. "Those antennas will just be naturally more directional, like talking over megaphones. Every phone will have its own megaphone," rather than distributing RF all over at every angle.

For more:
- see this FCC release
- see this NYU Wireless release

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