5G Speeds Just Aren't Good Enough: 6G and 16K Are Inevitable
5G is barely out of the blocks but the starting gun has already been fired on what comes next. Research has begun into wireless technology that may be branded 6G, and the U.S. wants a head start.
"I want 5G, and even 6G, technology in the United States as soon as possible. There is no reason that we should be lagging behind on... something that is so obviously the future."
President Trump’s tweets in February were much derided, but the sentiment that the country should lead in communications tech was a message the Federal Communications Commission clearly received. A month later, the FCC voted to legalize tests in the terahertz wave spectrum and to issue 10-year licenses for experiments for “6G, 7G, or whatever is next.”
“These way-up there airwaves represent the new frontier,” stated Jessica Rosenworcel, an FCC commissioner. “There is something undeniably cool about putting these stratospheric frequencies to use and converting their propagation challenges into opportunity.”
She added, “I fear our unwillingness to do so will balkanize spectrum and cut short the possibilities.”
In contrast to 5G, which uses wavelengths (between 30 and 300 gigahertz) measured in millimetres (mmWave), the wavelengths the FCC has put up for grabs are in the 95 gigahertz (GHz) to 3 terahertz (THz) range. The top end of that—from 300Ghz upwards—are submillimeter waves.
The higher the frequency, the shorter the wavelength, and the shorter the wavelength the more data can be transmitted. Like 5G, any signal in the Thz range will suffer from attenuation and interference which will likely need both extreme directional beaming and a density of antennae an order of magnitude greater than 5G.
If these challenges are overcome, one outcome is download speeds 1000 times faster than the mere gigabit speeds of 5G.
The Promise of 6G
Some observers have suggested that if 5G goes according to plan there will be no need for a 6G. Other predict that something like 6G might be needed to shore up the parts of 5G implementation that have yet to take root. Another school believes that the evolution of network technology is inevitable and that major leaps happen roughly every decade—so we’ll be due another by 2030.
“A new mobile generation appears every 10 years, and so 6G will emerge around 2030 to satisfy all the expectations not met with 5G, as well as new ones to be defined at a later stage,” explained Matti Latva-aho, the Academy Professor at the University of Oulu in Finland.
Latva-aho is leading the $284 million-funded 6Genesis project to develop the components needed for 6G systems by researching “distributed intelligent wireless computing, device and circuit technologies, and vertical applications and services.”
The ITU, part of the United Nations, has assigned a task group to the matter called Network 2030. The working assumption is that in a decade we’ll be dealing in terahertz radio frequencies.
The Chinese have gone public with one study. The Southeast University in Jiangsu Province joined in predictions that 6G technologies will go into commercial operation by 2030 noting that “6G competition has already begun among many enterprises.”
We’ve barely scratched the surface of 5G’s promised superhuman capabilities to drive autonomous cars and gift us media and entertainment applications like 8K live virtual reality, multi-player real-time AR gaming and even holographic lightfields.
According to NYU Professor Ted Rappaport, however, 5G won’t be good enough.
“The use of mmWave in 5G wireless communication will solve the spectrum shortage in current 4G cellular communication systems that operate at frequencies below 6 GHz,” he writes in a paper published by the IEEE. “The increasing number of new applications such as VR/AR, autonomous driving, internet of things (IoT), and wireless backhaul (as a replacement for labor-intensive installation of optical fiber), as well as newer applications that have not been conceived yet, will need even greater data rates and less latency than what 5G networks will offer.”
That finding may come as a shock to telcos wanting to monetize next-gen consumer apps tomorrow in order to pay back investment in today’s 5G infrastructure.
Rappaport’s paper is important for being the most widely quoted on the subject of 6G. His lengthy academic text has been reduced in press reports to mean that "6G will stream human brain-caliber AI to wireless devices."
That’s bad shorthand for his own explanation which is that terahertz frequencies will likely be the first wireless spectrum that can provide the real-time computations needed for wireless remoting of human cognition. In short, that is true AI.
Media reports could equally well have been headlined "6G will steam human brains via wireless devices," since the “out there” frequencies being explored are borderline radioactive.
As Rappaport acknowledges, “Ionizing radiation, which includes ultraviolet, x-rays, galactic radiation, and gamma-rays, is dangerous since it is known to … lead to cancer.”
Some of these fears surround mobile phone use today, but the professor is optimistic a workaround can be found.
Science Fact or Fiction?
Perhaps just as speculative are potential applications for 6G. The short wavelengths at mmWave and THz will allow massive spatial multiplexing in hub and backhaul communications, as well as incredibly accurate sensing and imaging.
“The ultra-high data rates will enable super-fast download speeds for computer communication, autonomous vehicles, robotic controls, high definition holographic gaming, entertainment, video conferencing, and high-speed wireless data distribution in data centers,” says Rappaport.
In addition to the extremely high data rates, there are promising applications for future systems “that are likely to evolve in 6G networks and beyond." These fall into categories like wireless cognition, sensing, imaging, wireless communication, and localization or positioning.
One example is the opening up of a new dimension of wireless, that enables future wireless devices to do “wireless reality sensing” and gather a map or view of any location, leading to detailed 3D maps of the world created on-the-fly and uploaded and shared in the cloud by future devices.
It would make mobile game developer Niantic’s attempt at global real-time augmented reality location mapping look so last century. It would supercharge attempts by Magic Leap to superimpose a dimensional internet on the world around us.
As exciting as that all is, it might as well be science fiction.
Telcos have got to deal with the now which include early days rollout in select urban areas of 5G networks, the main use case for which on the consumer side is nothing more exotic than enhanced broadband.
“I think there will be a 6G but we have no way of knowing what it is,” says Kester Mann, director of consumer and connectivity at analyst CCS Insight. “The media and communications industry will always have visionaries wanting to look into future, and there has to be a focus on where you put future investment and R&D. But you could argue that the evolution of 4G has an awful long way to go. There’s plenty of room for 4G growth and it could perform many tasks and services that perhaps haven’t been invented yet, so all talk of 6G is more than a little premature.”
The noise about 6G overshadows the prosaic development of 5G and is analogous to a situation in the broadcast industry with UHD.
With 4K UHD still limited in distribution even in mature media economies like the U.K., and with many broadcasters worldwide (including some in the U.K.) yet to transition to HD, the increasing chatter around 8K UHD seems a distraction.
8K production kit is coming to market. For example, Blackmagic Design’s entire NAB 2019 messaging was around 8K. But this heavy metal—dedicated black box hardware working in SDI—is at opposite ends to the leaner flexi-workflow possibilities of IP which has barely got to grips with 4K UHD live production.
Certainly, 8K has its place as a recording format where the greater data overhead can help render higher quality visual effects or deliver more information to the final image for cinematographers wanting to mix resolution, aspect ratios, and sensor size.
The format will also find a home in live production for techniques such as region of interest—extracting 4K or HD images from a panoramic one.
At NAB, the 8K Association was formed to promote the format’s introduction. Its members include Hisense, Panasonic, Samsung Electronics, and TCL Electronics, and, in truth, it is display manufacturers that have the most to gain from pressing the 8K button so early.
Spanish-based Japanese-owned streaming movie service Rakuten TV plans to add 8K content to its catalogue by the end of the year and has announced partnerships with TV-makers Samsung, LG, Philips, and Hisense. There’s no sense of how much bandwidth that will require of home users and no mention of any 8K content. Though some of the latest TV displays do come with an HD or 4K auto-upscaling function to 8K.
Naysayers to 8K, as well as mobile operators suggesting that HD HDR is sufficient for video over 5G, argue that the human eye is blind to pixel resolution beyond 4K (especially on small screens).
That’s beside the point. The tech will be proved, use cases will be found, and the price per bit will come down. What’s more, other academic research suggests that our brains can, in fact, resolve more information beyond the retina.
“We need to envisage 16K and 32K—there will be certain applications for that,” Professor Kyoung-Min Lee from Seoul’s National University told lifestyle magazine EFTM. “But the limitation is infinite.”
You can bet Japanese broadcaster NHK already has 16K in its labs.
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