Interest in 6G has picked up momentum in recent weeks, even more so after US President Donald Trump’s tweet saying American companies must step up their efforts towards it. Now the Federal Communications Commission (FCC) has created a new category of experimental licenses for use of frequencies between 95 GHz and 3 THz, and this week industry and academia are meeting at a ski resort in Finland to map out the first collaborative effort to draft a joint vision of what 6G might look like.

The FCC is keen to encourage development of new communications technologies and expedite the deployment of new services in the spectrum above 95 GHz. It said there are substantial opportunities for innovation in these frequencies, especially for data-intensive high-bandwidth applications and for imaging and sensing operations.

To enable access to this spectrum, the FCC’s Spectrum Horizons First Report and Order created a new category of experimental licenses with durations of up to 10 years to give innovators the flexibility to conduct experiments, and to more easily market equipment during the experimental period.

It also makes a total of 21.2 gigahertz of spectrum available for use by unlicensed devices. The Commission selected bands with propagation characteristics that will permit large numbers of unlicensed devices to use the spectrum, while limiting the potential for interference to existing governmental and scientific operations in the above-95 GHz bands, such as space research and atmospheric sensing.

Prior to this decision, the Commission had no rules for authorizing communications above 95 GHz, other than by amateur operators or through experiments of limited duration and scope. This spectrum has long been considered the outermost horizon of the usable spectrum range, but rapid advancements in radio technology have made these bands especially ripe for new development.

White Paper on 6G Vision

Professor Ari Pouttu, vice-director of the 6G Flagship program at the University of Oulu, whom we spoke to last September about their 6G research in Finland, said it typically takes 10 years from starting research to getting to market, and he expects this could be the case for 6G too. Last week he told us, “Industry is just starting to roll out 5G, so we expect standardization for 6G may probably happen around 2030. This will be around the time when 5G peaks, and 4G will probably only peak around 2025.” He said the first industry timeline for 6G was presented at the IEEE Globecom Summit in Abu Dhabi last December.

3GPP roadmap 6G timeline Timeline presented for 6G at the IEEE Globecom Summit in Abu Dhabi last December. (Source: Professor Ari Pouttu, University of Oulu)

He said the University of Oulu has organized the 6G Summit in Finland as part of a three-day IEEE conference in Lapland covering future networks beyond 5G, mmWave localization, ambient and quantum backscatter communications, integrated circuit design for terahertz applications, and future IoT connectivity. Pouttu said around 270 people were registered so far, with speakers from industry, operators, regulators, and academia.

“The expected outcome [of the summit] will be the first white paper on 6G. All the players around the globe will come together with us and think about what 6G might be; and then together we will try to come up with a white paper to define the first ideas towards 6G, roadmaps, use cases, requirements, spectrum allocation and so on.” He said they’ll have all the key players including from China, Korea and the US, including Huawei, China Mobile, China Telecom, Ericsson, Qualcomm, Samsung, ETRI and NTT DoCoMo.

“It is a global event inviting everyone who is willing to contribute to 6G. We are just a university group licensed to talk freely. What we need is the opinions of global companies and other research groups in the world, and gradually come to some kind of a consensus on what 6G might look like.”

The last day of the three-day conference this week will specifically address 6G visions and potential technologies. Speakers include Peter Vetter of Nokia Bell Labs, Wen Tong of Huawei, Magnus Frodigh of Ericsson, Juho Lee of Samsung, Takehiro Nakamura of NTT DoCoMo, Qi Bi of China Telecom, Guangyi Liu of ChinaMobile, Kwon Dong-Seung of ETRI, Bernard Barani of the European Commission as well as several academics from around the world.

IC Design for Terahertz Applications

One of the speakers, Ullrich R. Pfeiffer, who holds the high-frequency and communication technology chair at the University of Wuppertal, Germany, will present on integrated circuit design for terahertz applications, and radio front-ends for 100 Gbps and beyond. He’ll explore both the challenges and opportunities for emerging applications and circuits as we push towards terahertz frequencies and look at recent attempts to operate silicon technologies close to and beyond their transistor cut-off frequencies. Silicon BiCMOS process technologies have recently reached an fmax as high as 0.7 THz, which enables circuits to operate fundamentally up to about 300 GHz with reasonable RF circuit performance.

Beyond fmax, where transistors do not provide power gain, circuits may be operated sub-harmonically to further extend the operating region. At terahertz frequencies, on-chip antennas may be implemented with reasonably high efficiencies and very small area, eliminating the need for additional external components such as expensive waveguides or horn antennas.

Pfeiffer will cover fundamental and sub-harmonic RF circuit design methodologies, RF power generation techniques and their limitations at terahertz frequencies (>300GHz), terahertz circuit characterization methodologies, a summary of SiGe HBT terahertz benchmarking circuits and examples of 240GHz Tx/Rx chipsets for communication, a 240GHz radar transceiver, and heterodyne and direct detection circuits up to 1THz.

6G Standardization

There are already multiple programs around the world looking at various aspects of next-generation networks. Finland has allocated €251m over eight years for its 6G flagship program focused on supporting industry in bringing 5G to commercialization and to explore development of essential technology components that could be needed for 6G. China had already started researching next-generation (6G) mobile communications last year; the ITU has a focus group looking at backbone technologies for next-generation networks in 2030; and the Semiconductor Research Corporation has a Center for Converged Terahertz Communications and Sensing looking at technologies for future cellular infrastructure using hubs with massive spatial multiplexing, providing 1 to 100 Gb/s to the end user, and with 100 to 1,000 simultaneous independently modulated beams and aggregate hub capacities in the tens of Tb/s.

Professor Pouttu said that while 6G standardization will have new challenges in terms of materials and communications, it could also be the end of the smartphone as we know it, in terms of the way we consume data. New human-machine-interfaces are likely to transform this – for example, with printable electronics, you could have a conductive surface on the table, tap on the table, and have a newspaper or specific web site appear on the table. Or the same could be done on glass surfaces around the home or in buildings.

He also touched on possible changes in standardization. Specifically, groups like 3GPP and GSMA are driven by ICT companies and operators, and don’t fully take into account the many different vertical industries that next generation networks will impact. He commented, “Is it time to do this standardization somewhere else? Because the standardization group has to serve all the verticals, and currently there are no verticals inside 3GPP. It’s just ICT companies. 6G is going to have so many different facets, that it remains to be seen who can do this.”

6G

6G businesscases Potential business cases for 6G (Source: University of Oulu)