by Jörg Wiebusch
First of all, I would like to say in advance that I am definitely convicted: Wi-Fi 6 is more performant! Maybe different than most would expect, but definitely better. I would take up a colleague comparison here. It is not necessarily about pure speed, as for example with a highly tuned car that is incredibly fast on the highway, i.e. on the straight. It’s more about performance through efficiency. More like a perfectly tuned sports car – great cornering, high acceleration, efficient consumption – etc.
So it’s not about pure speed, but about performance through efficiency. Why is that? I would like to take up these questions below and present my view of things. I would like to briefly take up the previous standards and take a quick look at the features of Wi-Fi 6.
Probably now many of you may think, I have already heard that, read it, attended three webinars and also upgraded or renewed my infrastructure with the first available access points. If this is the case, you are theoretically already in possession of a highly efficient infrastructure. I hope that the access points have also been planned and installed accordingly so that the infrastructure does what it is supposed to do. And that’s what Wi-Fi 6 can really do better from my point of view: be more efficient! Efficiency through good planning, correct installation and assembly and also the correct setup. Here, too, I would like to take up my colleague’s comparison once again. Only the right chassis setting, the right engine management and the right tyres make the lap fast. Only the right interaction of many individual parts leads to success. Just like the sports car, the wrong setup can ruin the performance.
The different standards
Let’s take a closer look at the WLAN standard 802.11ax. What is the difference to the previous standard 802.11ac, the supposed “Gigabit WLAN”? Why should the standard be so much better? What does he do differently? At this point, I would like to review the various stages of development and work my way up from the traditional to the current standard. Interesting for those who want to briefly enter the history of technology and revel in a little nostalgia. So a quick trip back in time, then in high speed through the WLAN standards and then “back to the future” … oh sorry present.
I think many still know the “good, old, robust” WLAN according to 802.11b or .11g standard. 54Mbit/s gross data rates were the upper limit. At this point I will no longer mention the older standards, pure 11Mbit/s components should have really disappeared by now. I think a good comparison would be a Volvo 240 station wagon. Robust, not slow, gets everything, does its job to this day. Then came the standard 802.11n (now called Wi-Fi 4) with data rates up to 600Mbit/s (very theoretical – practically usually up to 300Mbit/s). Here we are already at a VW Passat, slightly larger engine, newer year of construction. Has already become more convenient, faster, quieter. Wi-Fi 4 was followed by fast WLAN with Wi-Fi 5 (802.11ac – the “Gigabit WLAN”). Theoretically, data rates of up to a fantastic 6.9 Gbit/s are possible here. But even here it was or will be practically no more than 400 or 800Mbit/s. I’ll say Audi S4 or Audi S6.
Now comes the new standard Wi-Fi 6. Let’s compare this one as well. Here we are theoretically already at a maximum of 9.6 Gbit/s, which in practice comes to a maximum of 573Mbit/s or 1147Mbit/s. M Power BMW? For example, M3 Touring. Any objections?
So it’s faster,…
Yes, now you can say: “See, it fits! Wi-Fi 6 makes everything faster”. You can argue like that but I would still be a little more cautious. “But that’s about 40 percent more data throughput (400 Mbit/s in Wi-Fi 5 to 573 Mbit/s in Wi-Fi 6 standard). That’s a lot more boom, isn’t it?” That’s right. However, I would like to put a small damper on the whole thing. Just because a truck has 800hp, it is still not faster than a VW Polo.
Expressed in pure numbers, this may well be true. Under certain circumstances, I can achieve these data rates. This includes high signal strengths, channel bonding and also a “clean” environment with regard to the frequency spectrum. Above all, the point of channel bonding is the decisive factor. The ever higher data rates were “bought” from standard to standard with the fact that more and more channels were bundled. For Wi-Fi 4, it was 40MHz channel bandwidth. Twice as much as in the old 802.11g standard (Wi-Fi 3). In the Wi-Fi 5 (802.11ac) it was already 80 and 160Mhz, as well as in the current Wi-Fi 6 standard. There are, of course, more technical details, but the main reason for the ever-increasing speeds lies in the bundled channels. Why these bundled channels are a bad idea in reality or why the upcoming extension Wi-Fi 6E promises us a decisive improvement here are actually already topics for the next blog entry. That goes beyond the scope at this point. Let’s just note here that in almost all infrastructures that come with more than a handful of access points, a channel bandwidth of more than 40Mhz (and only in certain cases) is unfortunate.
But how is it that Wi-Fi 6 is faster, better, more efficient? Why, then, is this standard constantly talking about more performance and “better, faster, higher, further”? Is this all just a marketing gimmick to sell new hardware? Well, with the last statement you are never completely wrong if you want to annoy the corresponding manufacturer. I am happy to give the answer to this question at the end. First of all, the little technical tricks with which this succeeds.
A little more technology
Let’s start with physics. Very overdrawn, but the difference between the two standards Wi-Fi 5 (802.11ac) and Wi-Fi 6 (802.11ax) is due to this. With Wi-Fi 6, changes and improvements are made to both Layer 1 (physics) and Layer 2 (MAC Layer). In the case of 802.11ac, this was technically referred to as VHT (Very High Throughput), while Wi-Fi 6 called this combination HE (High Efficency). That brings us closer to the matter.
While the 802.11ac standard was primarily dedicated to increasing speed, the current standard tries to use the medium (frequency spectrum) more efficiently. There are all the technical details like 1024QAM, OFDMA as modulation, BSS colouring, TWT (Target Wake Time), resource units and so on. In depth, I don’t want to elaborate on them. Again, this would be a separate topic (so slowly the ideas fill up).
In general, with the new coding method (1024QAM) significantly more symbols can be encoded in the radio wave than in the previous standard. Of course, this in itself ensures faster transmission – or rather more data in the same time. But this also requires better quality, higher quality radio modules to encode and decode these symbols. This in combination with BSS colouring alone ensures better performance. How?
In simplified terms, BSS Colouring allows the identification of the same radio cells (with the same channel) with different IDs (the colour). Wi-Fi 6 radio modules allow higher tolerances as to when a client is allowed to broadcast (as part of the medium access procedure). The radio modules can therefore identify the radio cells based on the BSS Colour and communicate with them, although another radio cell (with the same channel) is also nearby. Thus, clients and access points can communicate better with the new standard (more sensitive radio modules) and the tolerance when a client is allowed to broadcast is reduced (more access to the medium). If I now add the new modulation OFMDA, with which several clients can be addressed simultaneously in one (original) channel (in parallel via the resource units already mentioned) and add the TWT (the Power Save behavior of the clients), then I can use the medium much more efficiently. And if I can use something more efficiently (the medium), then my infrastructure will also be more performant. Here I pick up the chassis, brakes, tires and tuning again. The lap gets faster. Whereby I have to admit that especially the topic of BSS Colouring and ALSO OFDMA actually rather ensure that I can now drive on the previously 3-lane motorway with nine cars next to each other (if the cars fit together – i.e. the WLAN clients).
So faster or more efficient?
As mentioned, I would like to take this point to protect the manufacturers a little. A lot of marketing doesn’t mean that there aren’t quite meaningful extensions. I definitely take this point for granted with the new Wi-Fi 6 access points. The standard fits very well into the IT lifecycle and also offers enough arguments to sensibly replace in parts (or migrate smoothly) or maybe even replace in one step the existing infrastructures of older generations.
Is it fair to say that the marketing departments and also the general opinion that the new standard is “faster” are right? You can certainly see it that way . However, one should understand that this is not due to pure data throughput, but to the functioning of the new standard.
After all this “pros and cons” I would like to finally dissolve. Does Wi-Fi 6 increase performance or efficiency? Yes, definitely – and both. Wi-Fi 6 is not necessarily faster, but with a proper design, it is more efficient and therefore more performant. From my point of view, there are several reasons for this and I subscribe to both points. The standard is much more efficient and thus increases the performance of your WLAN infrastructure if all points are neatly coordinated. This applies to the planning, the hardware, the conception, as well as the configuration and above all the clients. In other words, I can drive fast, really fast, but I can also handle obstacles better, overtake better with tight corners and in heavy traffic.
Thus, in the end, both are correct. However, from my point of view, a little different than you might expect at first. Only if everything is neatly coordinated with each other, I get performance through the effective use of the resources available to me. Only the appropriate planning and the right design lead to success!