While 5G is still very much a work in progress, industry thoughts are already turning towards the next generation of mobile connectivity: 6G.
Historically, there’s been a 10-year gap between one generational leap in mobile technology and another, and if specifications for 6G are locked down as early as next year that means a target date of 2030 for commercial rollout.
While discussions about the successor to 5G are serious and growing in number, the substance of a 6G network remains vague.
The Next Generation Mobile Networks (NGMN) Alliance is taking a very high-level view of the status of 6G. This group includes T-Mobile, BT, NTT Docomo, Orange, KPN, China Mobile, Telefonica, Vodafone, and Canada’s Bell (but not AT&T or Verizon).
NGMN’s framework for building a 6G network sets out “the imperative to satisfy three fundamental needs facing the society at large, and the telecoms industry specifically,” namely: the need to address societal objectives at large, notably the UN’s Sustainable Development Goals; the need to satisfy customer requirements by offering new services and capabilities, supported by evolving technologies in a cost-effective manner; and the need to make the planning, deployment, operations, management, and performance of the mobile operator’s networks increasingly more efficient.
As one can see, these needs are so broad they could apply to 5G, AI, VR, Blockchain, or virtually any emerging technology.
The sustainability goal is a key focus of the NGMN. “This includes energy efficiency and adoption of green technologies and green energy, towards carbon neutrality, for this decade and beyond, and should be a fundamental design consideration for 6G,” it states. This can only succeed with a holistic approach by the entire ecosystem, including global standards, ecosystem design, service footprint, metering and monitoring, and deployment strategies.
READ MORE: 6G Drivers and Vision (NGMN)
The NGMN goes on to say that it expects 6G “in its novelty and capabilities” to meet the three drivers it outlined, “and, in addition, break new frontiers with respect to environmental impact, societal benefits, users, scenarios, players, value creation and spectrum,” to drive new business models, “and potential new paradigms unknown today…. We also require features of 6G to be introduced in a way that enhances trustworthiness, security and resilience.”
One of its members, Japan’s NTT Docomo, has gone further in a paper outlining what to expect of 6G that 5G cannot.
This includes high-fidelity mobile holograms, any camera to any device anywhere, completely cable-free video production, and the possibility of replicating physical entities, including people, objects, systems, and places in a virtual world. If you’ve heard that before then you’ll be thinking “metaverse,” with 6G perhaps ushering in the processing power and speed to deliver real-time online interactivity.
READ MORE: DOCOMO 6G White Paper (NTT Docomo)
6G connectivity is envisaged to deliver peak data rates of the order of terabits per-second together with sub-millisecond latency in the sub-terahertz and terahertz ranges.
These peak rates are unlikely to be delivered over wide areas but might be useful for some use cases in localized areas. As such, there is interest in the potential use of frequencies in the sub-terahertz and terahertz ranges to provide the bandwidth to deliver these peak data rates and to enable the intensive use of spectrum within localized areas.
This encompass spectrum between 90GHz and 300GHz, which is between millimeter-wave and infrared. For more information on that, visit the Brave Research Project, a collaborative research project investigating new PHY-Layer technologies to reach beyond-5G data rates and capacities.
READ MORE: Sub-THz frequencies (Brave Research Project)
According to consultants Analysys Mason, the characteristics of sub-terahertz/terahertz frequencies are very different from those of the bands used today for wide-area, contiguous coverage in mobile networks. Potential use of sub-terahertz frequencies in 6G therefore raises fundamental questions in terms of usage environments, use cases, network topologies, and devices, the consultant advises.
“It remains unknown how sub-terahertz frequencies might be deployed together with the spectrum and architecture used in today’s mobile networks. This will be the subject of further research, industry debate and standardization over the coming years.”
READ MORE: The terahertz frequencies that are expected in the 6G era offer both opportunities and challenges (Analysys Mason)
A key consideration for 6G lies in how the network architecture used in 4G and 5G mobile networks today might evolve to address future traffic volumes, while also catering for the new use cases that might emerge with 6G.
It will be challenging to integrate terahertz frequencies into existing mobile network architecture since terahertz communication only occurs over short ranges (of the order of 100 meters) and therefore communications will be limited to “line of sight,” explains Analysys Mason, pointing to how much this will cost.
“Such dense infrastructure, or even a move to user-centric, ‘no cell’ architecture, does not appear to be commercially viable for providing contiguous coverage given the level investment required, and hence would be limited to localized deployments.”
Other key infrastructure is needed as well. RedSharkNews lists these as antenna technologies, an evolution of duplex technology, an overhaul of network topology, spectrum sharing, the still nebulous promise of AI, split computing (i.e. utilizing computing resources in the edge and further into the cloud), and high-precision networks. These are all name-checked and backed by different organizations.
READ MORE: Coming up next: 6G (RedSharkNews)
Low Earth Orbit satellites of the type being built by Amazon and SpaceX could also take advantage of 6G.
“Satellite is one of the key ways that 6G could be differentiated from 5G from the start,” says RedSharkNews. “That was always terrestrial network first, satellite considerations second. Flip that around, or at least balance it, and you could potentially accelerate the rollout and make it more uniform at the same time.”
Some observers point out that the timeframe for advancing a new generation mobile network has come from 15 years to eight years, hence the optimistic scenarios of a 2030 6G deadline.
“6G will emerge around 2030 to satisfy the expectations not met with 5G, as well as the new ones fusing AI inspired applications in every field of society with ubiquitous wireless connectivity,” states University of Oulu, a Finnish development program reporting to the International Telecommunication Union (ITU).
Others are more skeptical and a long timeframe feels about right when you consider that operators have barely scratched the surface of making their money back on 5G.
But then why stop there? There is already chatter about 7G, including this prediction from Technology Trend:
“We will have actual mass-market adoption of 5G by 2025. We should expect 6G in the 2035 timeframe and 7G in the 2045 timeframe.”