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

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

#81

Post by p_j_w »

KingMachiavelli wrote: post #4

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.

802.11ax introduced some changes that have real world effects: subcarrier spacing was decreased by a factor of 4. Symbol length was increased by the same factor, but that means receiver sensitivity requirements are looser for the same data rate. So, for the same signal strength you can get a higher data rate. I’ve personally seen this effect on my own phones and laptops: I get consistently higher throughput on ax networks than I do on ac.

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

#83

Post by martinald »

jhoho wrote: post #82

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.

Not sure if that's true really - its just 6GHz is a lot less congested in general (for now).

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

#84

Post by martinald »

dnemmers wrote: post #30
anyfoo wrote: post #5

Earlier quoted context omitted.

Due to boring circumstances outside of my control, I have to use WiFi for the most part, so I've got quite some experience with making it run optimally (or rather, as optimally as I managed to, not as optimally as I would like it to). And yeah, you pretty much already have to have a visible line of sight to get anything even close to 1 Gbps. And still be on channels with little interference. (DFS helps if you're not…

Have you thought about using powerline devices? I’ve successfully used them in place where running my own cable wasn’t a possibility, and WiFi wasn’t cutting it. https://www.hp.com/us-en/shop/tech-takes/what-is-a-powerline...

Powerline is in my experience vastly worse than WiFi in nearly all cases. It's slow, suffers from bad jitter/interference (often worse than WiFi) and the chips run so hot (especially the last gen ones, AV2000 iirc - I believe they don't sell them any more because they overheat and fail, or at least 2/2 of the ones I had did this).

Even with many walls I was getting 300-400mbit/sec on WiFi vs 100mbit/sec on powerline.

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

#86

Post by Marsymars »

Normal_gaussian wrote: post #28

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 ther…

> The 4x4 makes all the difference.

I've stuck with my Eero Pro 6 because it has 4x4 at 5GHz and the Pro 6E and 7 trade that for 2x2 at both 5GHz and 6GHz. The Max 7 has 4x4 on both 5Ghz and 6Ghz, but for a 3-pack for my house, the current pricing on amazon.ca is $2300, compared to the $650 I paid for the Pro 6 3-pack. (And the Pro 6 seems to have notably lower power draw than the Max 7.)

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

#87

Post by jhoho »

martinald wrote: post #83
jhoho wrote: post #82

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.

Not sure if that's true really - its just 6GHz is a lot less congested in general (for now).

I struggle to find good resources on this topic. The few I found indeed attribute the lower latency of more recent Wi-Fi generations to techniques like MLA and OFDMA, not necessarily the frequency (which makes sense, of course). The cudy link makes it look like channel congestion is a factor, too. https://www.rtings.com/router/learn/research/wireless-latenc... https://www.zbtwifi.com/blogs/frontier-technology-news/wi-fi... https://www.cudy.com/en-benelux/blogs/news/6-ghz-vs-5-ghz-th...

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

#88

Post by supertrope »

AdityaAnuragi wrote: post #85

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

Qualcomm did a test with extreme levels of traffic. As in 20 simultaneous video chat sessions. https://www.qualcomm.com/content/dam/qcomm-martech/dm-assets...

For contention between nearby Wi-Fi networks the BSS coloring feature is more directly relevant.

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

#89

Post by BrandoElFollito »

wonnage wrote: post #13
anyfoo wrote: post #12

> 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…

yeah, it's pretty common to refer to x^2 as exponential colloquially since there's A. an exponent B. a single term for all values (vs. quadratic, cubic, quartic...) But you're technically correct!

> it's pretty common to refer to x^2 as exponential colloquially since there's A. an exponent B. a single term for all values (vs. quadratic, cubic, quartic...)

Where is it pretty common? I have never heard that (outside of being a mistake)

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

#90

Post by supertrope »

blindriver wrote: post #32

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 kno…

If a device can still hear a farther away AP at say -62 dBm it’s not going to start searching. Searching has a cost in lower speeds and higher latency due time spent tuning to other channels. It’s only done if the current signal weakens. Decrease AP transmit power until each room only has one AP signal at -67dBm or louder. https://support.apple.com/guide/deployment/wi-fi-roaming-sup... Intel Wi-Fi cards have a roaming aggressiveness setting.
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