Will there be 6G?

Will we have 6G?

Whenever being asked this question, I always start my answer with the paraphrase of a quote from prof. Andy Sutton, “If we get 5G right, there will be no need for 6G” [1]. This is because I fully agree with that quote, although it doesn’t hold anymore, as we already have 5G and the research community works on 6G.

Introduction to the perspective of Next G’s

I’d like to make some points out of it which can be generalized towards whateverG happens next:

• There is a marketing aspect to it, from which there will always be nextG, because vendors need to sell nextG to the operators every now and then. Going further, the operators would like to sell the nextG service to the customers.
• From a technical standpoint, there could potentially be a “lastG” which doesn’t mean of course that this is the ultimate solution to all human problems. It means that it’s designed in such a way that every new technology which will happen in the future can be added to the “lastG” in a plug-and-play manner as we move to software-based solutions. This is, I assume, what prof. Sutton had in mind in his statement. The problem is that we have to make the “lastG” right, which is difficult when you have pressure and hype around the nextG. This requires so that you (here I mean 3GPP or whoever is standardizing the nextG system) have to do it fast, which more or less means that it probably will not be done “right”.
• From a historical standpoint, every odd generation provided the “new” type of service / big thing to the mobile communications (1G started „voice” in mobile communications, 3G started Internet access, 5G started native incorporation of verticals), while every even generation provided the “improved” solution for the services approached by the odd generation (2G provided good voice communication solution, 4G provided a good solution to Internet access). For that reason and by approximation, we will need 6G to fix the 5G flaws when first time approaching verticals.

Even and Odd G’s

To elaborate on the last point, Figure 1 shows the evolution of mobile wireless systems, emphasizing two aspects: first, key services, which those systems were designed to provide; second, a general assumption captured when designing them.

I would like to underline two conclusions that could be drawn from Fig. 1 [2]. Firstly, as already mentioned in the previous section, the odd generations provide (to date) an approach to new requirements, along with services that were not present before (e.g., 1G for mobile voice, 3G for mobile Internet access), while the even generations represent the evolution of the odd ones, “correcting” the design of the predecessors to properly deliver the main service. Secondly, until the 4^th Generation, the network was designed with a “single” design approach, also known as “one-size-fits-all”, because there was a single main service to address (e.g. voice or Internet access).

With the emerging 5^th Generation (along with the emerging Internet-of-Things (IoT) and new vertical markets, as well as ever-increasing need for capacity and throughput for broadband access) the perspective has changed. In the current situation, there is no single “killer application”, to be served by the system, but rather the system should be able to cover a multitude of services with diverging requirements. Those services, like high throughput mobile broadband (addressed by eMBB), through extremely low latency communications (with URLLC), down to low-end MTC (Machine-Type Communications) applications with very sporadic transmissions using several bytes (with mMTC), call for support of different connectivity approaches. Thus, the 5G system should be flexible enough to cover those requirements [3].

How 6G fits here?

Following the conclusions stated above, it can be said, that the 5^th Generation of mobile wireless systems is the “odd” version, approaching this collection of services for the first time. Whether there will be a need for 6G to “fix the 5G legacy mistakes” – time will tell – but one thing is certain. Without a new approach to the system design, it will be difficult to proceed, as 6G is expected to focus on further extending the service diversification. So in this context, the requirement, that there is no single application or service to focus the efforts on will hold [4][5].

References

• [1] https://www.fiercewireless.com/special-report/europe-accelerates-push-toward-a-5g-wireless-future
• [2] Disclaimer: this paragraph presents solely my viewpoint and is quite simplified (e.g. does not include all the intermediate steps with the GPRS and HSPA+, which make the transition points from 2G-to-3G and from 3G-to-4G respectively). Other ways of classification of the mobile system generations present in the industry typically consider higher speeds and lower latencies from generation to generation.
• [3] M. Rahnema, M. Dryjanski, “From LTE to LTE-Advanced Pro and 5G”, Artech House, 2017.
• [4] M. Dryjański, „A Hierarchical and Modular Resource Management in the Future Wireless Systems„, Ph.D Dissertation, June 2019
• [5] E. Calvanese Strinati et al., “6G: The Next Frontier: From Holographic Messaging to Artificial Intelligence Using Subterahertz and Visible Light Communication,” IEEE Vehic. Tech. Mag., vol. 14, no. 3, Sept. 2019

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