NEW YORK — Governments around the world must agree to release spectrum in harmonized millimeter wave bands for 5G cellular services, according to a leading researcher in the field. The US has taken some, but not enough, steps in this direction, said Theodore Rappaport, director of NYU Wireless here.
“To keep cost down, and get adoption rates to be very high, it will be better for the industry to have common frequency bands to use with the same chipset,” Rappaport said in an interview with EE Times.
Korea, China, and Japan are being “very aggressive” in leading the charge to 5G. NTT Docomo in Japan is expecting 5G standardization in 2016 and, in May, announced trials of “emerging 5G mobile communications technologies” with Alcatel-Lucent, Ericsson, Fujitsu, NEC, Nokia, and Samsung. They aim to exploit frequency bands above 6 GHz with very high system capacity per unit area, as well as prove radio technologies to support M2M services.
Meanwhile, the European Union’s 5G Infrastructure Public Private Partnership is also making inroads in exploring 5G.
“As a US citizen, my concern is that the federal policy is ignoring the opportunity to build the technical talent and to get the investment needed to ensure that the US plays a role in the massively broadband future,” said Rappaport. “I think millimeter wave could [have]... bandwidth and capability so far beyond what we’ve seen in wireless... But without a spectrum policy that focuses on supporting and encouraging such products, we’ll be left behind.”
Frequency allocations in the United States.
(Source: NYU Wireless)
The US isn’t completely ignoring the need for regulations around 5G. Michael Ha, deputy chief of the FCC's Policy and Rules Division, said at the Brooklyn Summit the commission has issued a notice of inquiry on millimeter wave feasibility for cellular with a focus on frequencies less than 95 GHz. Ha speculated on changes in licensing models, and he suggested the FCC might consider a sharing model with incumbents.
Separately, researchers need to solve the issue of getting masses of data and users to base stations in a very inexpensive way. Backhaul is one of the biggest costs for carriers, Rappaport noted, and the millimeter wave spectrum may provide backhaul in addition to alleviating user congestion. The use of frequency agile receivers and transmitters may be key, he said.
Rappaport also sees fiber playing a large role connecting base stations and networks. In addition, antennas capable of millimeter wave transmissions should be able to act collectively and steer traffic intelligently. Smart repeaters paired with frequency agile receivers and transmitters will add to the intelligent system.
Samsung is already researching this field. At the IEEE International Microwave Symposium in June, the company presented a paper describing its use of 16 antennas on the edge of a Galaxy Note circuit board to create an adaptive array.
“I’ve known for a long time that you can make high-gain adaptive arrays at millimeter wave frequencies that fit in the palm of your hand,” Rappaport said. “So when you combine the idea of smart antennas in the handset with huge bandwidth at these frequencies it becomes clear you can take wireless to a whole new regime that’s never existed...
“The cellular and WiFi markets are so competitive and the advancements that are being put into silicon so remarkable that there’s already sort of a moat around breaking into that field. However, millimeter-wave technologies bring a whole new set of challenges where some new entrants will be able to make a stand -- but it’s going to be tough.”
— Jessica Lipsky, Associate Editor, EE Times