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

414 points by homebrewer 5mo ago

WillPostForFood 5mo ago
I was on top of G, started to lose track after N.
Neywiny 5mo ago
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
Havoc 5mo ago
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
- anyfoo 5mo ago
  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 near radar, which intentionally causes you to get kicked off those channels and lose connection entirely.) And even then you might have to mess about a lot with positioning, because of reflections and generally multipath propagation. I'd say it's not worth the headache. I would love to lay down Ethernet cable, even if it was just cabling only suitable for 1 Gbps (for which there's no good reason to, might as well do 10 Gbps). But yeah, any mesh system worth its salt figures out the topology and absolutely favors wired links over WiFi for the back haul. Anything else wouldn't make any sense at all, there is basically no situation where you'd prefer an RF channel over a wire, unless the wire is maybe made of wet string.
  - walrus01 5mo ago
    > And yeah, you pretty much already have to have a visible line of sight to get anything even close to 1 Gbps If one considers that the higher speeds in 802.11ac and 802.11be require 256QAM modulation or better, this is completely expected (assuming 5 GHz band of course, which doesn't go through material very well at all). If you've sen a live eyeball chart of a 256QAM or 1024QAM constellation on test equipment for clear-air microwave link purposes, and seen how quickly it can degrade or get fuzzy if there's anything in the way of the link, it becomes more readily apparent. MCS levels 8 and onwards here: https://en.wikipedia.org/wiki/Wi-Fi_7 https://en.wikipedia.org/wiki/Wi-Fi_7 "Clean" eyeball example of 256QAM: https://www.everythingrf.com/community/what-is-256-qam-modulation https://www.everythingrf.com/community/what-is-256-qam-modul... examples of "fuzzy qam" in 16QAM, same principle applies to denser QAM https://www.researchgate.net/figure/Typical-eye-diagram-Symbols-1-to-10-000-from-a-random-16-QAM-sequence-Symbols-10-001-to_fig2_3316716 https://www.researchgate.net/figure/Typical-eye-diagram-Symb...
  - dnemmers 5mo ago
    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-adapter https://www.hp.com/us-en/shop/tech-takes/what-is-a-powerline...
    - martinald 5mo ago
      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.
    - izacus 5mo ago
      Powerline in practice does not come anywhere near performance of a good WiFI7 setup - even through walls WiFi tends to be more stable and faster outside special conditions (e.g. multiple floors or thick walls).
- walrus01 5mo ago
  how many spatial streams are you using (2x2, 3x3, etc) and are you using an 80 or 160 MHz channel? If you have a set of full capability 802.11be clients you'll see the best performance with a 3x3 AP and 160 MHz channels.
  - Havoc 5mo ago
    160hz channel & 2 spatial streams. It's unfortunately consumer grade tp-links so while they have actually been pretty good...you don't get a lot of knobs to tweak. Still need to try MLO at some stage and they're currently acting as a bridge so (i.e. wifi backhaul) so think it might get better once I've laid fiber backhaul between them
    - walrus01 5mo ago
      Would recommend one of the ubiquiti 3x3 802.11be APs for better performance. The U7 Pro or similar. The unifi controller software is a monolithic package you can install on a bare bones debian system. Wifi backhaul definitely also a problem as using any kind of wifi-to-wifi extender stuff will cut your throughput a lot, keep in mind that all 802.11.whatever is a half duplex medium.
      - Havoc 5mo ago
        >3x3 The ones I have seem to be 2x2...with backhaul on wifi the 1.3 I'm seeing is probably just 1 then. Aware of ubiquiti popularity in homelab circles. It's not for me tbh. I've been through a couple of iterations of wifi gear - including a mainland china no-english Xiaomi...that was an adventure. At this stage I don't think I'm tearing it out and buying new. "slow" gigabit internet on mobile device is an annoyance to my perfectionist side but I'll survive. And with a bit of luck adding fiber backhaul gets me above internet speed.
- kalleboo 5mo ago
  My house is built out of reinforced concrete, so wireless signals reach almost nowhere. I got Ethernet put into the living room and bedroom and put in 2.5 Gbps USB ethernet dongles on powered hubs, so when I plug into my phone/laptop to charge they get wired ethernet automatically.
KingMachiavelli 5mo ago
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.
- crims0n 5mo ago
  Surely some of that was need. When G was dominant from around 2004-2009 the theoretical maximum was 54mbps… most people were still on DSL or cable at the time, often capping out way below that.
- niobe 5mo ago
  I would agree with that. G to N was perhaps the most critical move in Wi-Fi because it included MIMO. You can think of this as unwanted signal echoes and reflections being switched from a liability to a benefit. Heck, I _still_ run WiFi-4 networks and they perform very well. WiFi-5 was an incremental upgrade, with many experimental features that barely used in practice. 802.11 is in general a vast swag of cool tricks, and when enough ideas are thrown at a wall, many do end up sticking, but for the most part the benefits are cumulative. MIMO being one major exception.
- dylan604 5mo ago
  Does any of it have to do with the spectrum becoming available? After 2.4GHz and 5GHz, I have no idea what else the latest/future gens of WiFi are using. As some tech like 2G is no longer in operation, that spectrum was opened up. There are other frequencies that have become available where operating the older equipment that used to operate there is a big no-no now. There was a frequency range used by old wireless microphone systems that are banned at locations. Just taking a swing at it, but I don't play that sport so probably a big whiff
  - ssl-3 5mo ago
    In regulatory regions where it is usable, Wifi 6 (802.11ax) added some 6GHz channels. Wifi 6e extended that to roughly the entire 6GHz band, for ~1GHz of contiguous RF bandwidth in that area alone. The "old" cellular bands aren't generally open, at least in the States. We tend to use them for newer licensed stuff in cellular-land instead of the old licensed stuff we used to do. (Old modulation techniques die out and get replaced, but licensed RF bandwidth is still licensed RF bandwidth.)
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ibatindev 5mo ago
Once again, IEEE 802.11ah -Wi-Fi HaLow-, completely forgotten. This one would be perfect for all the lights/sensors.
- walrus01 5mo ago
  Latest-gen zigbee stuff and zwave 800 seems to have already thoroughly occupied that niche for a great deal of home and office automation equipment.
- Avamander 5mo ago
  There aren't any usable chipsets with usable drivers for 802.11ah unfortunately.
anyfoo 5mo ago
> 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").
- wonnage 5mo ago
  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!
  - amluto 5mo ago
    Do you also think that f(x) = x^1 is exponential? How about f(x) = x^0?
    - anyfoo 5mo ago
      Kind of irrelevant, because you could also ask "Do you also think that f(x) = x^1 is polynomial? How about f(x) = x^0?" The distinction was clearly between polynomial (specifically quadratic) and exponential, leaving those trivial cases out.
    - Jaxan 5mo ago
      No. These are polynomials (in x).
  - anyfoo 5mo ago
    I'm actually not sure that they don't actually mean exponentially. There's something about not only increasing the distance, but potentially also the modulation (and thus the symbol rate) stepping down, which maybe in total causes the decline to be ~exponential? But it's not clear to me at all. That's why I ask, I have a hard time parsing it. But then again, the sentence uses the term "signal strength", not "throughput", so that would suggest quadratically. But I guess "signal strength" could be meant colloquially and mean more than just the raw signal power received by the antenna, here. It's all very fuzzy to me, as it stands.
niobe 5mo ago
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.
- Onavo 5mo ago
  Well the newer WiFi standards on 6Ghz support a lot more channels. Not a perfect work around by any means but it does significantly reduce congestion.
  - niobe 5mo ago
    Yes, that helps quiet a lot in practice because in most places there's limited "frequency-domain" capacity (i.e. free channels) but plenty of "time-domain" capacity, (i.e. free air-time). So even if you are sharing a channel with 4 other APs and their users, everybody may subjectively feel the network is fast. When chopping up the time domain into nanoseconds there's just a lot of idle time available, even if clients are pulling down files at 600Mbps. But at a fundamental level, the channel space (~60 across all bands best case) is extremely limited but the potential growth in transmitters is unbounded. It's like a linear hack to an exponential problem. It seems to work at first, but under very high load conditions performance still degrades ever faster until it falls off a cliff. Then there's all sorts of complex dynamic behaviour like the hidden node problem to add to this, but it all boils down to needing air-time and SNR.
    - rayiner 5mo ago
      > But at a fundamental level, the channel space (~60 across all bands best case) is extremely limited but the potential growth in transmitters is unbounded. You’re overlooking the spatial dimension: https://en.wikipedia.org/wiki/Spatial_multiplexing https://en.wikipedia.org/wiki/Spatial_multiplexing
Normal_gaussian 5mo ago
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.
- bityard 5mo ago
  Interesting... I have a Netgear WAX218, one of the last cheap business-class APs I could find that don't require a cloud service to manage. WAY better than the pro-sumer wifi routers I was running before in access point mode. I'll have to look into Zyxel offerings a bit more when I'm ready to replace my Netgear.
- bjoli 5mo ago
  Inwas about to buy a pair of those, but then I saw the new mikrotik wifi 7 router (and probably upcoming access point) with thread radio. Now every other brand is dead to me.
  - ece 5mo ago
    What are the chances of a 3x3 or 4x4 router from them I wonder.
    - bjoli 5mo ago
      Slim to none, I would guess.
  - Normal_gaussian 5mo ago
    That is really interesting! (https://mikrotik.com/product/hap_be3_media https://mikrotik.com/product/hap_be3_media for others). Its coming in at a decent price as well.
- izacus 5mo ago
  What benefit does 4x4 give you? I haven't seen a single client station with more than 1x1 or 2x2. Do you have so many clients that transmit concurrently?
monk_grilla 5mo ago
Anyone know of a similarly excellent resource for understanding wired networking? CAT specifications, how to pick high quality switches/routers etc.?
- lake_trade 5mo ago
  Beej's guide will help you with understanding networking overall, I don't think it would help you choosing switches/routers specifically.
  - NooneAtAll3 5mo ago
    link?
blindriver 5mo ago
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.
- jauntywundrkind 5mo ago
  There's band steering. You absolutely do have control, if you opt to do so. On openwrt, DAWN or usteer can both help your APs to get sounding maps from clients and to tell them which AP to join. Looking at the sounding maps is very fun data to see: highly tecommend! The settings aren't the world's greatest but they are pretty good starts! https://github.com/berlin-open-wireless-lab/DAWN https://github.com/berlin-open-wireless-lab/DAWN https://openwrt.org/docs/guide-user/network/wifi/dawn https://openwrt.org/docs/guide-user/network/wifi/dawn Multiple APs are really nice because you can turn down the AP power, ideally, as you add more stations. Unfortunately I don't think you can tell a client to be quieter though; someone's laptop can be at 200mW tearing the hell out of the spectrum when everyone else is nicely conversing at 10-20mW.
  - toast0 5mo ago
    My experience with DAWN wasn't great. Some of my clients don't like the extensions you need, so I had to go back to no roaming extensions and just hoping clients make good decisions and tuning ap power levels to help. Might try it again though, I'd love for it to work. And I was also dealing with some baseline wifi instability that I think firmware updates has resolved.
  - blindriver 5mo ago
    Band steering doesn't work great. Neither does minimum RSSI. It's completely client-dependent and it's a headache. The best solution is to always minimize the number of APs you have with as little overlap as possible because of how unpredictable client behavior is. Like I said I have a very bad problem with line of sight APs are ignored for further away APs, and no amount of fiddling is helping.
Dylan16807 5mo ago
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.
- deleted 5mo ago
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oofabz 5mo ago
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.
dbcooper 5mo ago
Love this site for communicating the properties of WiFi protocols.
ece 5mo ago
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.
saejox 5mo ago
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
- abhinavk 5mo ago
  6(ax) works on 2.4GHz too.
mbesto 5mo ago
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.
- ipython 5mo ago
  At some point, you just can’t beat physics. For best results you need multiple aps anyway.
- myself248 5mo ago
  And 802.11ah, in 900MHz which has some hope of penetrating such walls, is still very scarce and the hardware fairly expensive. Otherwise you just have to run a wire through the wall and put an AP in the room. Your clients can still be wireless for the last few feet, which preserves the convenience of usage, just not the convenience of deployment.
  - mbesto 5mo ago
    This is basically my strategy.
jhoho 5mo ago
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.
- martinald 5mo ago
  Not sure if that's true really - its just 6GHz is a lot less congested in general (for now).
  - jhoho 5mo ago
    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-latency https://www.rtings.com/router/learn/research/wireless-latenc... https://www.zbtwifi.com/blogs/frontier-technology-news/wi-fi-7-vs-wi-fi-6e-real-world-performance-comparison https://www.zbtwifi.com/blogs/frontier-technology-news/wi-fi... https://www.cudy.com/en-benelux/blogs/news/6-ghz-vs-5-ghz-the-clear-winner-for-online-gaming https://www.cudy.com/en-benelux/blogs/news/6-ghz-vs-5-ghz-th...
AdityaAnuragi 5mo ago
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
- supertrope 5mo ago
  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/documents/ofdma_white_paper.pdf 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.
Scroll_Swe 5mo ago
WiFi is always a compromise. Wife factor maybe, but for now, cable.
skadge 5mo ago
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/d3f854f6111e8275ae54fca14bb0e9b9 https://gist.github.com/severin-lemaignan/d3f854f6111e8275ae...
peter_d_sherman 5mo ago
I like this table in the page very much: https://www.wiisfi.com/images/wifi-phy-table.jpg https://www.wiisfi.com/images/wifi-phy-table.jpg Basically, it shows how a different encoding scheme/modulation is used based on distance (1024-QAM 5/6 - BPSK 1/2) (https://en.wikipedia.org/wiki/Signal_modulation https://en.wikipedia.org/wiki/Signal_modulation), which is interesting! If we think about it, any WiFi adapter (in its most basic core functionality) is just the ability to send/receive radio at a specific frequency, and a modulation (send) and corresponding demodulation (receive) scheme on top of that. If the modulation/demodulation can be handled by a DSP, FPGA or fast-enough CPU, then all that's really required to create a WiFi device is that and the radio component, and then of course, there are devices like "Cantennas" that could give increased range, although loss of omnidirectionality is the trade-off there... Anyway, I never thought about the fact that different encoding methods are used relative to distance prior to reading this article (i.e., I learned something!) -- but it makes perfect sense now that I think about it!

414 points by homebrewer 5mo ago

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

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

Havoc 5mo ago

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

anyfoo 5mo ago
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 near radar, which intentionally causes you to get kicked off those channels and lose connection entirely.) And even then you might have to mess about a lot with positioning, because of reflections and generally multipath propagation. I'd say it's not worth the headache. I would love to lay down Ethernet cable, even if it was just cabling only suitable for 1 Gbps (for which there's no good reason to, might as well do 10 Gbps). But yeah, any mesh system worth its salt figures out the topology and absolutely favors wired links over WiFi for the back haul. Anything else wouldn't make any sense at all, there is basically no situation where you'd prefer an RF channel over a wire, unless the wire is maybe made of wet string.
- walrus01 5mo ago
  > And yeah, you pretty much already have to have a visible line of sight to get anything even close to 1 Gbps If one considers that the higher speeds in 802.11ac and 802.11be require 256QAM modulation or better, this is completely expected (assuming 5 GHz band of course, which doesn't go through material very well at all). If you've sen a live eyeball chart of a 256QAM or 1024QAM constellation on test equipment for clear-air microwave link purposes, and seen how quickly it can degrade or get fuzzy if there's anything in the way of the link, it becomes more readily apparent. MCS levels 8 and onwards here: https://en.wikipedia.org/wiki/Wi-Fi_7 https://en.wikipedia.org/wiki/Wi-Fi_7 "Clean" eyeball example of 256QAM: https://www.everythingrf.com/community/what-is-256-qam-modulation https://www.everythingrf.com/community/what-is-256-qam-modul... examples of "fuzzy qam" in 16QAM, same principle applies to denser QAM https://www.researchgate.net/figure/Typical-eye-diagram-Symbols-1-to-10-000-from-a-random-16-QAM-sequence-Symbols-10-001-to_fig2_3316716 https://www.researchgate.net/figure/Typical-eye-diagram-Symb...
- dnemmers 5mo ago
  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-adapter https://www.hp.com/us-en/shop/tech-takes/what-is-a-powerline...
  - martinald 5mo ago
    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.
  - izacus 5mo ago
    Powerline in practice does not come anywhere near performance of a good WiFI7 setup - even through walls WiFi tends to be more stable and faster outside special conditions (e.g. multiple floors or thick walls).
walrus01 5mo ago
how many spatial streams are you using (2x2, 3x3, etc) and are you using an 80 or 160 MHz channel? If you have a set of full capability 802.11be clients you'll see the best performance with a 3x3 AP and 160 MHz channels.
- Havoc 5mo ago
  160hz channel & 2 spatial streams. It's unfortunately consumer grade tp-links so while they have actually been pretty good...you don't get a lot of knobs to tweak. Still need to try MLO at some stage and they're currently acting as a bridge so (i.e. wifi backhaul) so think it might get better once I've laid fiber backhaul between them
  - walrus01 5mo ago
    Would recommend one of the ubiquiti 3x3 802.11be APs for better performance. The U7 Pro or similar. The unifi controller software is a monolithic package you can install on a bare bones debian system. Wifi backhaul definitely also a problem as using any kind of wifi-to-wifi extender stuff will cut your throughput a lot, keep in mind that all 802.11.whatever is a half duplex medium.
    - Havoc 5mo ago
      >3x3 The ones I have seem to be 2x2...with backhaul on wifi the 1.3 I'm seeing is probably just 1 then. Aware of ubiquiti popularity in homelab circles. It's not for me tbh. I've been through a couple of iterations of wifi gear - including a mainland china no-english Xiaomi...that was an adventure. At this stage I don't think I'm tearing it out and buying new. "slow" gigabit internet on mobile device is an annoyance to my perfectionist side but I'll survive. And with a bit of luck adding fiber backhaul gets me above internet speed.
kalleboo 5mo ago
My house is built out of reinforced concrete, so wireless signals reach almost nowhere. I got Ethernet put into the living room and bedroom and put in 2.5 Gbps USB ethernet dongles on powered hubs, so when I plug into my phone/laptop to charge they get wired ethernet automatically.

KingMachiavelli 5mo ago

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.

crims0n 5mo ago
Surely some of that was need. When G was dominant from around 2004-2009 the theoretical maximum was 54mbps… most people were still on DSL or cable at the time, often capping out way below that.
niobe 5mo ago
I would agree with that. G to N was perhaps the most critical move in Wi-Fi because it included MIMO. You can think of this as unwanted signal echoes and reflections being switched from a liability to a benefit. Heck, I _still_ run WiFi-4 networks and they perform very well. WiFi-5 was an incremental upgrade, with many experimental features that barely used in practice. 802.11 is in general a vast swag of cool tricks, and when enough ideas are thrown at a wall, many do end up sticking, but for the most part the benefits are cumulative. MIMO being one major exception.
dylan604 5mo ago
Does any of it have to do with the spectrum becoming available? After 2.4GHz and 5GHz, I have no idea what else the latest/future gens of WiFi are using. As some tech like 2G is no longer in operation, that spectrum was opened up. There are other frequencies that have become available where operating the older equipment that used to operate there is a big no-no now. There was a frequency range used by old wireless microphone systems that are banned at locations. Just taking a swing at it, but I don't play that sport so probably a big whiff
- ssl-3 5mo ago
  In regulatory regions where it is usable, Wifi 6 (802.11ax) added some 6GHz channels. Wifi 6e extended that to roughly the entire 6GHz band, for ~1GHz of contiguous RF bandwidth in that area alone. The "old" cellular bands aren't generally open, at least in the States. We tend to use them for newer licensed stuff in cellular-land instead of the old licensed stuff we used to do. (Old modulation techniques die out and get replaced, but licensed RF bandwidth is still licensed RF bandwidth.)

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ibatindev 5mo ago

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

walrus01 5mo ago
Latest-gen zigbee stuff and zwave 800 seems to have already thoroughly occupied that niche for a great deal of home and office automation equipment.
Avamander 5mo ago
There aren't any usable chipsets with usable drivers for 802.11ah unfortunately.

anyfoo 5mo ago

> 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").

wonnage 5mo ago
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!
- amluto 5mo ago
  Do you also think that f(x) = x^1 is exponential? How about f(x) = x^0?
  - anyfoo 5mo ago
    Kind of irrelevant, because you could also ask "Do you also think that f(x) = x^1 is polynomial? How about f(x) = x^0?" The distinction was clearly between polynomial (specifically quadratic) and exponential, leaving those trivial cases out.
  - Jaxan 5mo ago
    No. These are polynomials (in x).
- anyfoo 5mo ago
  I'm actually not sure that they don't actually mean exponentially. There's something about not only increasing the distance, but potentially also the modulation (and thus the symbol rate) stepping down, which maybe in total causes the decline to be ~exponential? But it's not clear to me at all. That's why I ask, I have a hard time parsing it. But then again, the sentence uses the term "signal strength", not "throughput", so that would suggest quadratically. But I guess "signal strength" could be meant colloquially and mean more than just the raw signal power received by the antenna, here. It's all very fuzzy to me, as it stands.

niobe 5mo ago

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.

Onavo 5mo ago
Well the newer WiFi standards on 6Ghz support a lot more channels. Not a perfect work around by any means but it does significantly reduce congestion.
- niobe 5mo ago
  Yes, that helps quiet a lot in practice because in most places there's limited "frequency-domain" capacity (i.e. free channels) but plenty of "time-domain" capacity, (i.e. free air-time). So even if you are sharing a channel with 4 other APs and their users, everybody may subjectively feel the network is fast. When chopping up the time domain into nanoseconds there's just a lot of idle time available, even if clients are pulling down files at 600Mbps. But at a fundamental level, the channel space (~60 across all bands best case) is extremely limited but the potential growth in transmitters is unbounded. It's like a linear hack to an exponential problem. It seems to work at first, but under very high load conditions performance still degrades ever faster until it falls off a cliff. Then there's all sorts of complex dynamic behaviour like the hidden node problem to add to this, but it all boils down to needing air-time and SNR.
  - rayiner 5mo ago
    > But at a fundamental level, the channel space (~60 across all bands best case) is extremely limited but the potential growth in transmitters is unbounded. You’re overlooking the spatial dimension: https://en.wikipedia.org/wiki/Spatial_multiplexing https://en.wikipedia.org/wiki/Spatial_multiplexing

Normal_gaussian 5mo ago

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.

bityard 5mo ago
Interesting... I have a Netgear WAX218, one of the last cheap business-class APs I could find that don't require a cloud service to manage. WAY better than the pro-sumer wifi routers I was running before in access point mode. I'll have to look into Zyxel offerings a bit more when I'm ready to replace my Netgear.
bjoli 5mo ago
Inwas about to buy a pair of those, but then I saw the new mikrotik wifi 7 router (and probably upcoming access point) with thread radio. Now every other brand is dead to me.
- ece 5mo ago
  What are the chances of a 3x3 or 4x4 router from them I wonder.
  - bjoli 5mo ago
    Slim to none, I would guess.
- Normal_gaussian 5mo ago
  That is really interesting! (https://mikrotik.com/product/hap_be3_media https://mikrotik.com/product/hap_be3_media for others). Its coming in at a decent price as well.
izacus 5mo ago
What benefit does 4x4 give you? I haven't seen a single client station with more than 1x1 or 2x2. Do you have so many clients that transmit concurrently?

monk_grilla 5mo ago

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

lake_trade 5mo ago
Beej's guide will help you with understanding networking overall, I don't think it would help you choosing switches/routers specifically.
- NooneAtAll3 5mo ago
  link?

blindriver 5mo ago

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.

jauntywundrkind 5mo ago
There's band steering. You absolutely do have control, if you opt to do so. On openwrt, DAWN or usteer can both help your APs to get sounding maps from clients and to tell them which AP to join. Looking at the sounding maps is very fun data to see: highly tecommend! The settings aren't the world's greatest but they are pretty good starts! https://github.com/berlin-open-wireless-lab/DAWN https://github.com/berlin-open-wireless-lab/DAWN https://openwrt.org/docs/guide-user/network/wifi/dawn https://openwrt.org/docs/guide-user/network/wifi/dawn Multiple APs are really nice because you can turn down the AP power, ideally, as you add more stations. Unfortunately I don't think you can tell a client to be quieter though; someone's laptop can be at 200mW tearing the hell out of the spectrum when everyone else is nicely conversing at 10-20mW.
- toast0 5mo ago
  My experience with DAWN wasn't great. Some of my clients don't like the extensions you need, so I had to go back to no roaming extensions and just hoping clients make good decisions and tuning ap power levels to help. Might try it again though, I'd love for it to work. And I was also dealing with some baseline wifi instability that I think firmware updates has resolved.
- blindriver 5mo ago
  Band steering doesn't work great. Neither does minimum RSSI. It's completely client-dependent and it's a headache. The best solution is to always minimize the number of APs you have with as little overlap as possible because of how unpredictable client behavior is. Like I said I have a very bad problem with line of sight APs are ignored for further away APs, and no amount of fiddling is helping.

Dylan16807 5mo ago

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.

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oofabz 5mo ago

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.

dbcooper 5mo ago

Love this site for communicating the properties of WiFi protocols.

ece 5mo ago

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.

saejox 5mo ago

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

abhinavk 5mo ago
6(ax) works on 2.4GHz too.

mbesto 5mo ago

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.

ipython 5mo ago
At some point, you just can’t beat physics. For best results you need multiple aps anyway.
myself248 5mo ago
And 802.11ah, in 900MHz which has some hope of penetrating such walls, is still very scarce and the hardware fairly expensive. Otherwise you just have to run a wire through the wall and put an AP in the room. Your clients can still be wireless for the last few feet, which preserves the convenience of usage, just not the convenience of deployment.
- mbesto 5mo ago
  This is basically my strategy.

jhoho 5mo ago

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.

martinald 5mo ago
Not sure if that's true really - its just 6GHz is a lot less congested in general (for now).
- jhoho 5mo ago
  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-latency https://www.rtings.com/router/learn/research/wireless-latenc... https://www.zbtwifi.com/blogs/frontier-technology-news/wi-fi-7-vs-wi-fi-6e-real-world-performance-comparison https://www.zbtwifi.com/blogs/frontier-technology-news/wi-fi... https://www.cudy.com/en-benelux/blogs/news/6-ghz-vs-5-ghz-the-clear-winner-for-online-gaming https://www.cudy.com/en-benelux/blogs/news/6-ghz-vs-5-ghz-th...

AdityaAnuragi 5mo ago

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

supertrope 5mo ago
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/documents/ofdma_white_paper.pdf 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.

Scroll_Swe 5mo ago

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

skadge 5mo ago

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/d3f854f6111e8275ae54fca14bb0e9b9 https://gist.github.com/severin-lemaignan/d3f854f6111e8275ae...

peter_d_sherman 5mo ago

I like this table in the page very much: https://www.wiisfi.com/images/wifi-phy-table.jpg https://www.wiisfi.com/images/wifi-phy-table.jpg Basically, it shows how a different encoding scheme/modulation is used based on distance (1024-QAM 5/6 - BPSK 1/2) (https://en.wikipedia.org/wiki/Signal_modulation https://en.wikipedia.org/wiki/Signal_modulation), which is interesting! If we think about it, any WiFi adapter (in its most basic core functionality) is just the ability to send/receive radio at a specific frequency, and a modulation (send) and corresponding demodulation (receive) scheme on top of that. If the modulation/demodulation can be handled by a DSP, FPGA or fast-enough CPU, then all that's really required to create a WiFi device is that and the radio component, and then of course, there are devices like "Cantennas" that could give increased range, although loss of omnidirectionality is the trade-off there... Anyway, I never thought about the fact that different encoding methods are used relative to distance prior to reading this article (i.e., I learned something!) -- but it makes perfect sense now that I think about it!