4G is the past. 5G is rapidly becoming the present. 6G communication is the future. But what will it bring? Allow me to share my take.
November 6th 2020 saw what has become a routine successful rocket launch to space 1, delivering yet another bunch of 13 satellites into orbit. One of them is called Tianyan-5: dubbed to be the first 6G testing satellite.
Disclaimer: I am not an expert, just an excited enthusiast.
So wait just a minute. Aren’t we just figuring out 5G? Well, yes.. but we are figuring out its rollout. The standard itself is done. Work on 6G started earlier than you think: March 24, 2019 already saw a summit on 6G 2. So 6G is not science fiction. It’s just proof that science and progress waits for no man.
Let’s do a quick recap. 4G LTE has wavelengths of 10-40cm, with frequencies of up to 2Ghz. In layman’ terms: we can cram 10 or 20Mbps and the signal propagates quite well. It can reach 10km or further, and doesn’t mind obstacles that much.
5G must utilize multiple frequencies. The high range (30-300Ghz) is fantastic but its 1-10mm short waves degrade quite quickly and struggle to penetrate objects. A so called ‘mid band’ 5G (<6Ghz) is required to improve coverage (with less bandwidth). An an even lower band, 600-700Mhz to cover many square miles but only somewhat faster than 4G. So once more, in layman’s terms: the ‘best option’ will travel just a few hundred meters and would need a lot of towers. It can be very fast, but you are likelier to receive the lower bands. If you wish to read more about 5G, there’s an excellent white paper by Nokia 3 or a nice article at VB 4 for further reading.
Why even 6G?
6G? What is the point of further development? More speed? Well, sure, that’s always great. Some predict it to be able to reach into the terabits per second! But our planet is transitioning to a smart connected world of the internet-of-things (IOT). Our society is moving to be always-connected. In my humble opinion, the main benefit of 5G is not ‘the speed improvement’ but the fact that each tower can successfully serve thousands of connected devices. Thus we can move forward to making our cities smarter, more convenient and more efficient. While 5G should help us embrace IOT, 6G should elevate it to completely new, science-fiction-like level, In fact, the term connected things should make way for connected intelligence .
Key Research Areas
I want to briefly highlight several important research areas where a lot of time and effort will have to be spent.
When we talk about machine-to-machine communication, it is fast! Forget human scale. Latency (how long a signal takes to reach its destination) becomes very important. It is therefore one of the main pillars of research for 6G. 5G claims to cut latency times down to 1-10 milliseconds. This is somewhere between great and negligible for today. It will eventually become too slow when everything is connected. Imagine your message needs to travel through hundreds, thousands of ‘connected things’. Multiply your 10 milliseconds many times over, and you start to see the problem.
This naturally leads to the next research pillar: reliability. If we truly connect everything up: rely on machines running our homes, our transportation, our cities, we don’t want a network fault to bring down half the town. Only an utterly reliable solution is considerable.
The third key area of research I personally want to highlight is efficiency. Higher frequency waves need more energy. We want to produce more and more connected things. All of it needs power, and it must come from somewhere. I am really excited to live through the start of the green revolution. But what would happen if we drastically increased our electricity usage before catching up with the transition to green energy? Environmental impact is absolutely critical.
6G alone is not enough
Samsung has published a whitepaper 5 on their vision of the 6G communication era: hyper-connected experience in every corner of the world. A long, interesting paper that even I did not manage to read fully (happily there’s a summary in their newsroom 6), Many interesting topics are discussed, one of which I would also like to bring up.
There will be new advanced services in 6G era, which require a tremendous amount of real-time data processing, a hyper-fast data rate, and extremely low latency,
I am talking about mobile VR/AR, holographic displays, real-time in-depth health monitoring for an individual, a kind of cyber-realworld fusion that can often be found in science fiction. We will find ways to provide ultra low latency and ultra high network throughput. But if we lag behind in mobile computational capability? Or if don’t have a true revolution in battery technology? We would not be able to fully utilize 6G. How long would your IPhone 23 6G last with the lithium-ion battery of today?
6G communication In Space
Now, I don’t know if you’ve heard, but Nokia has been granted $14.1m by NASA to build 4G on the moon 7. It will eventually be expanded to 5G. So, VOIP on the moon. I think it’s a tipping point in our commitment to space. But why did China launch a 6G communication satellite into space 8? Well, it provides us with some special, favorable conditions to test things in. So why not test it there first? Honestly I don’t actually know! Maybe some of you can tell me more, or send me a link?
But then is 6G viable?
6G is expected to move into the terahertz frequency band. The wavelength is tiny. The challenges are enormous. A direct line of sight of a very narrow beam is a must. Forget obstacles. I mean research is looking into signal degradation due to water vapor absorption at 10 meter distance 9.
Fear not! Worldwide research is already ongoing how to solve these seemingly impossible challenges 10. Just don’t start saving up for that IPhone 23. 6G is not realistically expected to be commercially viable and available until 2030’s. We don’t even know what it will be, 3GPP 11 will decide that.