Now that 5G is becoming widespread what can we expect from 6G? [Q&A]

The 5G rollout is continuing, but technology companies, academics, service providers, and even governments are already starting to look ahead to the next generation of mobile technology.

So, what is 6G and what benefits will it offer over earlier standards? We spoke to Roger Nichols, 6G program manager at Keysight Technologies, to find out.

BN: What does 6G offer compared to 5G and LTE?

RN: 4G's advanced air-interface and all-packet-switched network resulted in a practical high-performance mobile internet. 5G was designed to overcome the constraints of 4G to enable more flexible and efficient use of the network resources -- depending upon demand.

5G is a more flexible technology focused on enabling industries beyond entertainment and advertising to make full use of wireless technology. These include:

• Flexible network design -- matching resource use with instantaneous demand,
• Higher reliability and resilience,
• Higher security and privacy,
• Much lower latency,
• Flexible scaling for capacity.

These changes mean industries -- from manufacturing, to mining, to healthcare, and to finance will be making much fuller use of wireless as 5G matures -- and some of that transition has begun.

6G will continue the relentless advancement of increasing data rates. However, as with the 5G vs. 4G comparison, 6G's larger contributions will enable deeper integration in day-to-day use across society, such as:

• Further advancements in reliability, resilience, and security.
• A much more flexible/programmable network. 6G will build on 5G's move from a hardware- to a software-focused network. 6G will take that step further for real-time adjustments and programmability enabling real-time changes in capabilities, not just depending upon a service-level agreement between two entities but reprogramming the network real-time on a per-session basis.
• Further integration of communications and computing infrastructure from client -- to edge -- to cloud.
• Leveraging artificial intelligence to optimize all the above.

BN: Will 6G represent a major leap, as from 4G to 5G, or will it be a seamless transition?

RN: I continue to read criticism in the media that 5G is not meeting expectations and 6G is restating some or the same original goals set even in the early days of 4G. One example was peak data rates. 4G’s target was 1Gbps and 5G's target is 10 or even 20Gbps. Did 4G miss the mark? And why is 5G so disappointing?

There is a fuzzy border between 'difficult' and 'impossible' objectives. While some would suggest that 4G's 1Gbps or 5G's 10Gbps goals were not realistic; without aggressive objectives, the industry would not be where it is today. I use a 4G link for my home broadband which provides peak uplink data-rates of 70Mbps. In 2006, I was part of Agilent's introduction of the first 3G base-station emulation update supporting the earliest versions of High-Speed Down Downlink Packed Access (HSDPA) at over 3.2 Mbps. We thought this was an absurd (high) data-rate speed and it would perhaps never be used. It takes little time for us to become accustomed to a level of performance and we do not remember how crazy the original objective sounded. While 4G has little chance of a peak data rate of 1Gbps, few would argue that 4G is not a successful technology. Some 5G lab demonstrations are showing as high as 8Gbps downlink and we are only 3 years into commercialization. We may not get to 10Gbps or 20Gbps; but as Richard Bach said, "Strive for your limitations, and sure enough, they are yours."

While not all 6G technology candidates will make their way to mainstream, enough of them will, for us, have a mainstream system in the mid 2030's, which will become taken for granted before the end of the decade. The prospects of a much more flexible system, with capabilities that can scale on multiple dimensions, (speed, capacity, latency, coverage, resilience, security) must be taken seriously and aggressive goals are how we will get there. I am optimistic about most of the technologies being investigated and while they may not manifest as is in popular visions today, they will be used in ways we cannot foresee -- this happens in every generation.

BN: Where are we currently on the 6G roadmap?

RN: We can expect to see the first work in 3GPP specifications begin around 2025. An unofficial industry consensus suggests the first implementable 6G features will come in Release 21 sometime around 2028. That said, there are two additional things to keep in mind. First, 3GPP is not the only specifications body who will contribute to 6G. Changes will have to be made by Internet Engineering Task Force (IETF), several parts of European Telecommunications Standards Institute (ETSI), and O-RAN to name a few. For technology to be standardized, much work must be done to develop and prove out the innovations needed to realize the vision -- the list is long, and each item has many levels of complexity. Standardization cannot start until we have more confidence in our ability to realize the technologies required.

BN: What sort of things will we see being developed to take advantage of 6G?

RN: Innovation and development are happening across that entire list of technology I provided above. Some of it is obvious (like the press-releases and publicity associated with Sub-THz radio systems for higher data rates and sensing applications); and some of it is not so obvious either because it is in 'trade secret' territory or it is in less-tangible areas -- more difficult to communicate or show off.

BN: What challenges lie ahead and when can we expect to see a 6G rollout begin?

RN: 6G will resemble previous generations in encountering many of the same general challenges:

• Spectrum policy: Increasing spectrum use for terrestrial wireless means co-existence issues with incumbents. Every new band introduced for use in an industry with a rapid cadence has an impact on an industry with a slower one. Spectrum is finite and hence there will have to be much work to optimize spectrum use and even improve sharing technologies.
• Financial: Trade journals agree that 5G subscriber rates and coverage maps are evidence of 5G rolling out faster than 4G. Many forget that 4G was launched at the beginning of a global financial recession and 5G was launched during an economic boom. We read in the same trade journals that 5G is not meeting expectations. This paradox is characteristic of the profound investments needed to make these technologies available for mainstream use coupled with the hype cycle - expectations are often unrealistic, and the financial impacts of an aggressive launch are significant.
• Geopolitical impact: Governments have never been more closely involved in the advent of a new wireless generation. Many deem wireless as a key element of national security. The risk of bifurcation (or further split) of a wireless standard is real. Previous generations have taught us that dueling standards drives up cost.
• Societal: Communications technology consumes power and other global resources and often for the sake of entertainment and advertising. However, communications technology can also cause energy and other resources to be conserved. Finding the right balance will be essential to a sustainable industry.
• Security: The increased threat surface combined with the innovation and organization of malefactors means security, privacy, and resilience are more critical than ever. Government policy always lags technology and policy with respect to cybersecurity remains stalled in the 20th century. Without a better policy framework, the risks to privacy and security are real and governments need to up their game.

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