Wi is Fi: Understanding Wi-Fi 4/5/6/6E/7/8 (802.11 n/AC/ax/be/bn) (opens in new tab)

An impressive attempt to summarise Wi-Fi which is a very deep topic. However I think the executive summary already missed the most critical thing about Wi-Fi:

only 1 transmitter at a time per channel - across all WLANs, yours and your neighbours, with no deterministic way to avoid collisions.

It's a shared medium and it's not even half duplex, unlike the dedicated full duplex you would typically get with an ethernet cable to a switch port.

The fact that Wi-Fi achieves what it does with this limitation, and how it co-ordinates the dance of multiple unknown clients using the same medium - and in the presence of other RF technologies to boot - is indeed an incredible technology story, but this achilles heel is the single most defining thing about Wi-Fi performance.

Very interesting reference article -- I've learn a lot!

In case someone is interested, I got Claude to create a small Linux tool that analyze the capabilities of your WiFi adapter + the current established Wifi link, and explain each of them based on wiisfi.com: https://gist.github.com/severin-lemaignan/d3f854f6111e8275ae...

I'd like to understand why the WiFi spec developed so slowly from G to N and finally to AC but now it's seems like a new version is released every other year yet many of the features/extensions are poorly implemented or have nearly 0 real world improvement.

> Wi-Fi signal strength decreases at an exponential rate as you move further away from a router.

This is surprising to me. I'd have guessed it decreases quadratically (i.e. due to the inverse square law), not exponentially.

The paragraph below seems to contain an explanation, but I don't really understand it (namely because I don't know what that percentage "Coverage" column actually means, or what we mean with "the total distance at each QAM step").

WiFi is always a compromise. Wife factor maybe, but for now, cable.

With Wi-Fi 6's OFDMA handling the hidden node problem better, does it actually make a noticeable difference in dense apartment buildings? Curious if anyone has measured this in practice

It seems the throughput has evolved over each spec but the reliability and distance hasn't, unless I'm mistaken? This is a big problem in place where concrete is used to build homes (e.g. the tropics) as the improvements to Wifi are basically not really relevant.

Anyone know of a similarly excellent resource for understanding wired networking? CAT specifications, how to pick high quality switches/routers etc.?

Today I set up a NWA210BE (Zyxel) to replace a unifi 6+ AP; I bought it second hand and my key metrics were: 4x4 MIMO, available used/discounted, current gen, fully functional standalone mode.

The 4x4 makes all the difference. Sitting in my car the 6+ would fight with my 4G for internet and cause maps to be super slow; now I'm off the property before its unusable.

I had intended to put APs in multiple rooms, but there doesn't seem like much point now.

While it already is a very deep discussion, like most it does not discuss the latency improvement that 6 GHz Wi-Fi brings. Afaik Wi-Fi 6E 6 GHz has a latency of 5 ms and less, while Wi-Fi 6 comes with about 10 ms at 5 GHz.

I recently got a Grandstream GWN7615 access point to add coverage on the other side of the house from the main router. It does not meet the minimum spec listed in this article but for more modest requirements I think it's an excellent value. You can get one for well under $100. It is WiFi 5, 3x3 MIMO, and you don't need any cloud account to manage it.

Nice detailed article!

Finding it increasingly difficult to avoid bottlenecks though. Even with wifi 7 I still get 1.3 on my mac and 0.5 on iphone. More than enough realistically, but upstream internet is 1.7 so tiny bit unfortunately

Think I'm just going to wire the place with 10 gig fiber

>The speed advantages that Access Points have over mesh systems will become much more obvious with Wi-Fi 7.

From what I've read mesh devices generally can detect when they've got wired backhaul so they can stay in mesh mode for the clean handovers while not relying on it for actually moving data

Good to see the subjective adjectives in the RF world are here too. Except they're not the same ordering, as EH is before UH for WiFi but after in RF

I hate how they did this big rebrand to simplify things and then immediately ruined it with 6e and 7.

Okay, we have wifi 6, now we're adding 6GHz. How do you know if you have 6GHz? You check if it says 6...e. And is wifi 7 an upgrade to that? Lol who knows, depends on the individual device specs. Check if it says tri-band, that will tell you it supports 6GHz... OR that it can support two simultaneous networks on one of the other frequencies.

Must wifi speed issues are actually obstacle issues. One concrete wall and wifi5/6/8 all dead. Only 4 survives. 2.4ghz is here to say

I was on top of G, started to lose track after N.

Love this site for communicating the properties of WiFi protocols.

Informative page, but the most common speeds with 2x2 MIMO probably were (in Mbps):

Far (QPSK) 4(20Mhz)/5(80Mhz)/6(160Mhz)/7(320Mhz): 28.8/130/288.23/576.47

Near (64QAM) 4(20Mhz)/5(80Mhz)/6(160Mhz)/7(320Mhz): 144.4/650/1,441.17/2,882.35

Not bad for throughput increases, though most of the increases come from more spectrum, and the reliability comes from more MIMO antennas/streams. I've had WiFi 4/5 2x2 routers and something tells me I won't see much more than what's listed above for 7. Buying a 4x4 does get you a generation of throughput in advance pretty much, if you need it.

Once again, IEEE 802.11ah -Wi-Fi HaLow-, completely forgotten. This one would be perfect for all the lights/sensors.

One thing that wasn't mentioned is that the more APs you have, the worst off your life gets. That's because the way clients connect to a particular AP is done client-side and you have no control over it or visibility. So, no matter how you fiddle with it, your client may connect to the AP that is 40 feet away and on another floor rather than the one that is 10 feet away with a perfect line of sight. And you won't know why. This is the problem I had with my house and had to decrease the number of APs to get over better reliability and performance.