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Wi-Fi Alliance introduces Wi-Fi 6

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Re: Wi-Fi Alliance introduces Wi-Fi 6

#41

Post by ericd »

jessriedel wrote: post #34
dev_dull wrote: post #29

From Wikipedi: > Though the nominal data rate is just 37% higher than IEEE 802.11ac, the new amendment is expected to achieve a 4× increase to user throughput due to more efficient spectrum utilization. >IEEE 802.11ax is due to be publicly released sometime in 2019.[2] Devices were presented at CES 2018 that showed a top speed of 11 Gbit/s.[3] Sounds good but with limited practical value while broadband speeds stay s…

I suspect for most WiFi users, the overwhelming need is more reliable and fast establishment of connection. I waste vastly more time trying to deal with flaky connections, reconnection after wake from sleep, and network priority issues than I do waiting in the rare cases the WiFi is limiting thd data transfer rate (rather than the wired connection). The timescales involved in making Wifi connections should be ms or l…

I've found Macs to be vastly better at this than my Linux/windows laptops, for some reason, to the point where I almost never wait for them to connect. Might just be some aggressive workarounds they've implemented, though.

Re: Wi-Fi Alliance introduces Wi-Fi 6

#42

Post by kalleboo »

forapurpose wrote: post #33
kbirkeland wrote: post #26

Earlier quoted context omitted.

The larger problem with the 2.4 GHz ISM band is the lack of non-overlapping channels along with only one station being able to transmit at a time per channel (in pre 802.11ax). There are only three non-overlapping 20 MHz channels in the 2.4 GHz unlicensed spectrum, where 5 GHz spectrum has about 21 (although some require active radar avoidance).

> The larger problem with the 2.4 GHz ISM band is ... only one station being able to transmit at a time per channel Is there any Wifi tech for which that isn't true, sans beam-shaping and other tech that effectively puts stations on different physical networks? How do 5 GHz technologies handle multiple simultaneous broadcasts on the same channel? How will 802.11ax do it? Signal processing? My impression, based on onl…

Maybe this?

https://en.wikipedia.org/wiki/IEEE_802.11ax#Technical_improv...

> Spatial frequency reuse

> Coloring enables devices to differentiate transmissions in their own network from transmissions in neighboring networks.

> Adaptive Power and Sensitivity Thresholds allows dynamically adjusting transmit power and signal detection threshold to increase spatial reuse.

> Without spatial reuse capabilities devices refuse transmitting concurrently to transmissions ongoing in other, neighboring networks. With coloring, a wireless transmission is marked at its very beginning helping surrounding devices to decide if a simultaneous use of the wireless medium is permissible or not. A station is allowed to consider the wireless medium as idle and start a new transmission even if the detected signal level from a neighboring network exceeds legacy signal detection threshold, provided that the transmit power for the new transmission is appropriately decreased.

Re: Wi-Fi Alliance introduces Wi-Fi 6

#43

Post by danggg »

joemi wrote: post #25

FINALLY. Confusing version numbering always annoys me, and wifi's "n", "ac", "g", etc version names (combined with the easy to get wrong "802.11") have been one of the biggest offenders for a while. When a version number is a marketable metric, it should not be confusing. Others notable offenders that jump to mind: the Xbox range (Xbox, Xbox 360, Xbox One, Xbox One X), iPhone SE and XR (since they break the pattern a…

It’s only you though... I find them very easy to follow.

Re: Wi-Fi Alliance introduces Wi-Fi 6

#44

Post by chrisweekly »

jessriedel wrote: post #34
dev_dull wrote: post #29

From Wikipedi: > Though the nominal data rate is just 37% higher than IEEE 802.11ac, the new amendment is expected to achieve a 4× increase to user throughput due to more efficient spectrum utilization. >IEEE 802.11ax is due to be publicly released sometime in 2019.[2] Devices were presented at CES 2018 that showed a top speed of 11 Gbit/s.[3] Sounds good but with limited practical value while broadband speeds stay s…

I suspect for most WiFi users, the overwhelming need is more reliable and fast establishment of connection. I waste vastly more time trying to deal with flaky connections, reconnection after wake from sleep, and network priority issues than I do waiting in the rare cases the WiFi is limiting thd data transfer rate (rather than the wired connection). The timescales involved in making Wifi connections should be ms or l…

THIS.

I've got good LTE signal in my neighborhood, and managed to convince AT&T's retention team to grant me 50GB/mo (whether or not I choose to tether my laptop, none of this "unlimited with tiny cap for hotspot usage" nonsense) ... I digress. I tend to turn my phone's wifi OFF, even when nominally in range of a trusted AP, to ensure a reliable connection. I'll take a steady 4-5 MBps over fragile and on-again/off-again 60MB anytime.

Re: Wi-Fi Alliance introduces Wi-Fi 6

#45

Post by chipperyman573 »

Gaelan wrote: post #16
kbenson wrote: post #10

Earlier quoted context omitted.

> Wi-Fi Alliance is naming the not-yet-complete IEEE 802.11ax standard as Wi-Fi 6, with ac being 5, and n being 4. One can guess then a is supposed to 1, b as 2, and g as 3, but this isn't mentioned anywhere I can see. Oh, I'm so happy it's a number that seems to correspond to something (as long as the next one is 7 or 8 or some integer slightly larger than 6). I look at wifi tech so rarely that I've mostly skipped a…

ac is later and presumably better. No idea if there are any trade offs

AC only supports 5gz, which has significantly worse range and is impacted much more by walls or other solid objects. But if there aren't a problem it's generally better

Re: Wi-Fi Alliance introduces Wi-Fi 6

#46

Post by mrb »

Really good whitepaper on WiFi 6 (802.11ax): https://www.cisco.com/c/dam/en/us/products/collateral/wirele... Also: http://www.ni.com/white-paper/53150/en/

Main differences with 802.11ac:

- denser subcarriers (or "tones") spacing; they are spaced by 78.125 kHz instead of 312.5 kHz, for example a 80 MHz channel now allows 980 data subcarriers, up from 234. That's a 4.19× improvement (4× higher density doesn't translate in exactly a 4× improvement because 11ac had a bit more "pilot" or "null" subcarriers not used for data.)

- new 1024QAM mode (encodes 10 bits per symbol, up from 8 bits with 256QAM). That's a 1.25× improvement.

- downside is that the symbol length had to be increased from 3.2 µs to 12.8 µs, and the symbol interval too from 0.4 µs to 0.8 µs. That's a 3.78× reduction in efficiency.

So the maximum data rate for a single stream on a 80 MHz channel increased by 4.19×1.25/3.78 = 1.39× between WiFi 5 and WiFi 6 (you can confirm it with published max data rate: 802.11ac = 433 Mbit/s, 802.11ax = 600 Mbit/s; and 600/433 = 1.39).

But the best feature of WiFi 6 is that different subcarriers can be concurrently used by different users, what they dubbed OFDMA (https://en.wikipedia.org/wiki/Orthogonal_frequency-division_...). This means that during the same 12.8 µs timeslot, even on a small channel like 20 MHz, you can have 9 concurrent users each assigned 26 subcarriers and each transmitting 26 different symbols (total of 234 symbols transmitted concurrently.) Whereas with WiFi 5, all subcarriers of the 20 MHz channel have to be used by the same user.

Re: Wi-Fi Alliance introduces Wi-Fi 6

#47

Post by [deleted] »

kevin_b_er wrote: post #3

Wi-Fi Alliance is naming the not-yet-complete IEEE 802.11ax standard as Wi-Fi 6, with ac being 5, and n being 4. One can guess then a is supposed to 1, b as 2, and g as 3, but this isn't mentioned anywhere I can see. As far as I can tell, all of these numbers are new. At least this naming is a good deal clearer than HDMI's confusing version and feature mix or USB's Speed names. What isn't clear is how much control th…

[deleted]

Re: Wi-Fi Alliance introduces Wi-Fi 6

#48

Post by WorldMaker »

cesarb wrote: post #17
rythie wrote: post #12

Earlier quoted context omitted.

> Wi-Fi Alliance is naming the not-yet-complete IEEE 802.11ax standard as Wi-Fi 6, with ac being 5, and n being 4. One can guess then a is supposed to 1, b as 2, and g as 3, but this isn't mentioned anywhere I can see. Most 802.11b and 802.11g devices didn't support 802.11a (due to it requiring 5Ghz), so I'm guessing version 1 is 802.11 and 802.11a isn't part of the version numbers.

I would put 802.11a as 3 together with 802.11g, since they have the same rates (and are basically the same tech in a different band, 802.11g feels like 802.11a ported to 2.4GHz plus some extra compatibility stuff).

It sounds like the Wi-Fi Alliance doesn't particularly care which one is 1, 2, and 3. They've only strongly defined 4 (n), 5 (ac), and 6 (ax). [1] It also sounds like they don't think enough devices are left in the wild of a, b, g, to worry about branding them.

The best description I've heard for 1-3 was to use roughly the consumer hardware adoption curve which was 1 (b), [briefly] 2 (a), 3 (g).

[1] https://www.wi-fi.org/discover-wi-fi

Re: Wi-Fi Alliance introduces Wi-Fi 6

#49

Post by WorldMaker »

colanderman wrote: post #11
kevin_b_er wrote: post #3

Wi-Fi Alliance is naming the not-yet-complete IEEE 802.11ax standard as Wi-Fi 6, with ac being 5, and n being 4. One can guess then a is supposed to 1, b as 2, and g as 3, but this isn't mentioned anywhere I can see. As far as I can tell, all of these numbers are new. At least this naming is a good deal clearer than HDMI's confusing version and feature mix or USB's Speed names. What isn't clear is how much control th…

Hm, I would expect 802.11-1997 to be 1. Is that 0? Or does it share a number with b, because they're the same technology? Or is it 1, and a and g share a number because they're the same technology? Or do a and b share a number because they were released simultaneously? (This is, of course, a Very Important Question.)

I think 802.11-1997 works as 0 in this case. The implication from the Wi-Fi Alliance seems to be they are counting consumer hardware generations, and there doesn't seem to have been much consumer hardware that was directly 802.11-1997 (it took b to get consumer adoption). Which is why the order I've heard that makes the most sense is 1 (b), 2 (a), 3 (g), because that was roughly the consumer hardwave waves, with the brief (a) hardware wave the fun out-of-order one.

Re: Wi-Fi Alliance introduces Wi-Fi 6

#50

Post by mrb »

chipperyman573 wrote: post #45
Gaelan wrote: post #16

Earlier quoted context omitted.

ac is later and presumably better. No idea if there are any trade offs

AC only supports 5gz, which has significantly worse range and is impacted much more by walls or other solid objects. But if there aren't a problem it's generally better

"AC only supports 5gz."

That's not an accurate statement. "802.11ac" denotes a set of features, and many of them apply to and benefit the 2.4 GHz band. For example 256QAM encoding boosts the max data rate by 20 or 33% on this band for, respectively, 20 and 40 MHz channels.

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