Given the fact that most experts recognize that 5G was over-hyped and is very unlikely to measure up to expectations for either its providers or its users, it’s no surprise that there’s interest in pushing its successor. At MWC there was a session on 6G, and this article described some of the views expressed. It’s worthwhile to take a look at the 6G situation, if for no other reason to lay out what we really need to be doing if we’re to create a useful next-gen mobile wireless technology.
The most insightful thing in the piece is the comment that “The projections are that the likes of you and I will only get 6G into our hot little hands from around 2030 onwards.” A Wikipedia article on 6G notes that “as of January 2023, there is no universally-accepted government or non-government standard for what qualifies as 6G technology.” Given that there was industry activity (the Alliance for Telecommunications Industry Solutions or ATIS) back in 2020, and that there’s almost a quarter-billion hits on “6G” on Google search, it seems that as we did with 5G, we’re getting the cart before the horse with 6G.
The article mentions some of the early-hype expectations: “100 times the capacity of 5G, with sub-millisecond latencies” The panel at MWC also talked about energy efficiency, more deployment scenarios including IoT and edge computing, better security, convergence of satellite and terrestrial networks, resilience, applications of AR/VR, better reception of cell signals in areas like tunnels and elevators, manufacturing robots, 3G mapping, metaverse, and so forth. If you combine these expectations with the reality points in the paragraph before, you can already see some interesting disconnects.
The most obvious problem is the classic “6G is a UFO” problem. It’s not landing in your yard for inspection, so you can assign it any properties you like. If we don’t have any agreed-on technology for 6G at this point, how do we know it will be a hundred times as fast as 5G? Can 6G radio waves travel faster than 5G or 4G? Obviously not, so how would 6G alone create sub-millisecond latency?
The next thing that should, at least, be obvious is that a lot of what we’re saying will come along through 6G was stuff we also promised with 5G, and clearly have not yet delivered. Why? Because a lot of things we promise for wireless standards are things that wireless standards can limit, but cannot create by themselves. In other words, what many standards (including 5G and the rational proposals on 6G) for wireless are doing is advancing communications so that it would not limit applications being contemplated, though not yet available. Will all the other barriers to those applications fall? We don’t know.
Those who’ve read my blogs know I’ve been pointing out that in order for many of the things we think 5G would enable to actually happen, we’d need an entire tech ecosystem to build up all the pieces. Edge computing, for example, doesn’t depend on 5G, it depends first and foremost on applications that drive enough value for the user and profit for the provider to create a business. That depends on broadening “provider” to mean not only the service provider, but the providers of critical facilitating technology to the service provider.
So what we’re saying here is that 6G is really aimed at advancing wireless communications so that it wouldn’t limit the growth of these new applications, not so that these new applications will suddenly burst on the scene. In order for the latter thing to happen, we’d have to see the entire application ecosystems emerge. The truth is that the real war for a rational next-gen wireless standard won’t be fought at the network level at all, it will be fought at the application software level. Maybe even more fundamentally, at the application targeting level, because what’s needed is some initiatives to determine where the application of things like low-latency computing could provide monetizable value.
Does this mean 5G and 6G are then so suppositional as to be essentially useless? No, surely not for 5G and very likely impossible for 6G as well. Why? Because there were, and will be, some learned and justified wireless service requirements mixed in with all the suppositional stuff. 5G hype said that it would increase user bandwidth by roughly ten to twenty times versus 4G LTE, and that it would increase total number of connected devices supported by ten times. The former, hasn’t proved to be true, and in any case there’s little you can do with a mobile device to exploit the higher theoretical speed. The latter is a significant benefit in controlling network costs, and thus service prices. We can expect that there will be 6G features that enhance the network’s economics and help build new business cases, but also things that will happen as a sort of insurance policy to protect the ability to support stuff we’ve not yet really thought of.
There’s a limit to be considered, though, even with respect to something like data capacity. Generally speaking, the amount of information (data) a wireless signal can carry is proportional to its frequency. To carry more, you have to use higher frequencies, which is why millimeter-wave signals can carry more data. The problem is that as frequencies go up, the radio network starts working more like radar, bouncing off things instead of going through them. That means that obstructions block the signals, and if you go high enough in frequency, even trees are a barrier. Some of the 6G hype, talking about terabit bandwidth, can be achieved only by raising frequencies to the point where they’d fail to penetrate almost anything, making them useless for practical cellular networks.
Why then are we having so many 6G discussions? Because “news” means “novelty”, not “truth.” Every tech publication, including this blog, has to consider the regular and awful question “What do we write about now?” There’s just so much that can be said about a given topic before it’s not “novel” and thus not “news”. More significantly, before people stop reading the stories, stop getting served the ads, and stop indirectly paying the sources. Not only that, there’s probably a thousand readers who might be interested in a claim of greater capacity, and almost none would want to read a story on mobile modulation.
The biggest problem with all of this is that it obscures the real, and useful, mission of keeping network and cellular standards ahead of the applications that would be connected. Absent some attention to the network issues, the network could be a barrier to investment in the very ecosystemic elements it depends on for long-term growth. Maybe we really do need 6G, a rational 6G. Whether we’ll get that may mean waiting until 2030 to see what emerges, I guess.