9 ms·

The reason the ISM bands look so "hot" or busy on a spectrum analyzer is exactly because they're a "free for all." It's a classic tragedy of the commons: everyo

by sinak 6y ago

The reason the ISM bands look so "hot" or busy on a spectrum analyzer is exactly because they're a "free for all." It's a classic tragedy of the commons: everyone keeps "shouting" at max volume to be heard and there's no coordination between operators and users of different services. Here's an example: in a typical apartment block, each resident runs their WiFi access point at full power. In any one apartment, there's a ton of interference from neighboring units. If everyone coordinated and reduced their WiFi power to just what was necessary to cover their unit, it would result in less interference and higher net data rates for everyone. But no one is incentivized to do take action unilaterally. LTE and 5G networks are very careful planned to limit intracell interference and handover zones between towers. This central planning maximizes the efficiency of the network. It allows your cell phone to connect to a tower 10km away if you're in a rural area, and results in higher spectral efficiency for the overall network by increasing signal-to-noise ratios for all users. With a more sensitive spectrum analyzer, you'll see that the cellular bands are actually extremely busy. In fact, macro networks are almost always at capacity during peak usage. However, all the devices are "speaking" at the lowest volume necessary to be heard.

Reason077 6y ago
> "If everyone coordinated and reduced their WiFi power to just what was necessary to cover their unit, it would result in less interference and higher net data rates for everyone. But no one is incentivized to do take action unilaterally." This is something that needs to be fixed in future WiFi specifications and enforced via device certification. You're lucky if a typical WiFi base station operator understands how to set channels, let alone adjust TX power levels. People expect to be able to plug in a base station and have it "just work", so coordinating with other nearby stations to optimize spectrum usage, minimize TX power, etc is something that needs to be automatic.
- jcelerier 6y ago
  > People expect to be able to plug in a base station and have it "just work", so coordinating with other nearby stations to optimize spectrum usage, minimize TX power, etc is something that needs to be automatic. ... isn't it ? my internet box is from something like 2014 and is able to choose the less used wifi band automatically.
  - danielheath 6y ago
    Can it choose to transmit quietly to avoid swamping nearby devices, or does it run the antenna at maximum transmit power?
  - reaperducer 6y ago
    It won't reduce its power to make nice with the neighbors.
    - alacombe 6y ago
      Power usage is based on the worse-case attenuation scenario, the last thing ISP want are call asking why wifi don't work good in the bedroom if the router is on the other side of the apartment / house. Thus transmitting at max allowable power is the best solution.
      - wtallis 6y ago
        > Thus transmitting at max allowable power is the best solution. Transmitting at the max allowable power is the selfish and dumb solution. It isn't the best solution, in a world with multiple overlapping WiFi networks. It isn't even a Nash equilibrium.
        pseudo0 6y ago
        Why do you think it isn't a Nash equilibrium? Any actor unilaterally choosing to transmit at lower power is going to experience worse signal quality, even if it's only marginally worse in some cases.
        wtallis 6y ago
        > Any actor unilaterally choosing to transmit at lower power is going to experience worse signal quality, even if it's only marginally worse in some cases. Yes, your received signal to noise ratio for that transmission will be somewhat decreased, and that might (or might not) hurt data throughput meaningfully. But it also means that your transmissions are causing less interference for your neighbor(s), and as a result your neighbor's equipment will not have to send as many retransmissions that potentially interfere with your own communications. It's a second-order effect, but also one that's proportional to how many neighbors you have in range that are trying to use the same slice of spectrum. So it's entirely possible that by unilaterally shouting less, you cause a significant reduction in wasted airtime that benefits both sides (though probably benefiting your neighbors more than you, depending on where your priorities lie between throughput and latency). It's not always a zero-sum game. In general (at least for WiFi), it's better to worry about airtime as the scarce resource rather than focusing on bytes per second. For fixed-rate wired networking, transmit time and bytes delivered are exactly proportional, but a variable-rate shared wireless medium decouples the two.
- londons_explore 6y ago
  Ummm... All WiFi devices adjust bitrate dynamically... For a given amount of data to be transmitted, adjusting bitrate up and freeing the channel quicker is equivalent to using a lower power for more time. Either way the disadvantages to other spectrum users are equal.
  - wtallis 6y ago
    > For a given amount of data to be transmitted, adjusting bitrate up and freeing the channel quicker is equivalent to using a lower power for more time. It's not an exact equivalence. It is often possible to reduce transmit power without having to also significantly reduce bitrate. See eg. https://blog.linuxplumbersconf.org/2014/ocw/proposals/2439 https://blog.linuxplumbersconf.org/2014/ocw/proposals/2439
    - londons_explore 6y ago
      Shanon says that it is an exact equivalence, provided transmit power is >> thermal noise (it is)... If in real world devices that isn't the case, that's a shortcoming of the devices or protocol.
      - wtallis 6y ago
        Well, obviously in the real world, devices do not have unbounded transmit rates. But you can get pretty damn close to the transmitter. The Shannon limit isn't the only relevant limit, and is no reason to dismiss out of hand an entire class of optimizations that do help in the real world. (Also, even if your equipment is capable of hitting the Shannon limit, I'm not convinced that transmitting at the highest power level is going to be optimal for multi-party communications with geographically distributed APs and stations. The information channel between my neighbor's AP and his laptop is neither identical to nor completely separate from the information channel between my AP and my laptop.)
      - kortilla 6y ago
        > If in real world devices that isn't the case, that's a shortcoming of the devices or protocol Yes, welcome to the real world. There isn’t any protocol/hardware in use that scales up bandwidth with signal indefinitely.
- wtallis 6y ago
  The current situation is particularly disappointing when you realize that a lot of WiFi devices have been capable of adjusting TX power on a per-packet basis (per frame, really) at least as far back as 802.11n hardware. So your router should never be shouting at your laptop that's in the same room, even if it would use full transmit power to reach a device in the attic/basement/yard.
  - Talanes 6y ago
    >at least as far back as 802.11n hardware. This made me realize how long it's been since I actually bought a router. The last time I was shopping around, getting 802.11n significantly narrowed the options.
    - wtallis 6y ago
      I'm impressed. The only good router I have left from that era has several Ethernet ports burned out, and the rest have too little storage and RAM to accommodate a recent OS with features like IPv6 support. And those are purchases from an era where 802.11n support was a given but dual-band 802.11n support was still reserved for more high-end products.
- abestic9 6y ago
  For frequency use, this already happens with automatic channel selection for neighbours, and DFS for avoiding a regulated frequency as soon as a signature is detected. WiFi 6 presents more efficiency with at a higher layer with BSS coloring to mitigate crowded channels. But as you said, most consumer wireless access points are still shouting over each other by default and it needs to be in the specification because there's zero incentive for a manufacturer to "worsen" their RF performance. It's a pointless consumer market IMO, most people don't need a Wireless LAN. Mobile carriers already provide Internet access to thousands of devices with just a handful of radios over several city blocks, but pricing means many homes end up standing up their own emitters for exactly the same purpose. Now we see bickering like this over what should be a far better coordinated EM spectrum. Worth note, most business/enterprise gear, which typically gets installed professionally, usually defaults to adjusting TX power automatically because more often than not it benefits the RF environment.
  - kbar13 6y ago
    people very often need to setup their own WAP because cellular providers sell metered connections on the order of GB/month, whereas comcast (the most prevalent ISP in america) meters at TB/month. in addition, not every device currently has the radio / components necessary to receive cellular data also there's the limitation that cellular providers often don't allow tethering (or more generally data access outside of the device the sim card is slotted in)
    - abestic9 6y ago
      What I was getting at but forgot to include in my comment. Unfortunately it’s still a distant dream of mine that all carriers, fixed or mobile, would simply provide a dumb pipe billed based on max throughput and nothing more.
- bronco21016 6y ago
  ... and to make matters even worse the solutions being marketed for fixing a lot of these problems are... MORE ACCESS POINTS! Every time a friend tells me about getting a mesh system to cover dead zones in their place I cringe at the thought of more 2.4 GHz blasting everywhere. 99% of the time the problem can be solved by better placing their current access point, whether that means moving their ISP provided router/AP, or installing a standalone AP and disabling whatever they're currently using for WiFi. I don't really know the answer to fixing the issues but it seems to me it's not technical, it's better information about placing the devices. End users just want it to work but don't have the time to learn how to best do that. ISP installers are not incentivized to care either, install as cheap and quickly as possible and get out. Mesh definitely isn't the answer though. It's the anti-answer.
  - ipython 6y ago
    But it’s part of the answer isn’t it? As I understand it the answer in general is more, smaller access points each with less tx power. My wish would be that those mesh extensions wouldn’t then rebroadcast the signal at max 2.4ghz power but then you’d be pilloried by ignorant YouTube reviewers who rank solely on “how many bars at max distance” In most cases I feel your best position is in the ceiling at the center point of the house. I did that myself but at significant cost - fishing cat5 thru walls and ceilings and repositioning the incoming wires to the basement. 99.9% of users will never take that approach.
    - bronco21016 6y ago
      That could be true. However, it's better to use wired backhaul than more WiFi for the backhaul. Commercial locations do many access points with smaller broadcast area but use copper to bridge everything together. You're right about the location aspect though. 99% of people will not be bothered. How do we change that? The ISPs could be incentivized to do higher quality install work perhaps? I'm not sure what the answer is. The eruption in popularity of pro-sumer installs using gear like Ubiquiti gives me some hope that slowly people will see the way. I've installed UAPs at 5 homes now over the last 6-7 years. Zero support calls.
- oasisbob 6y ago
  What about 802.11h? In addition to defining DFS, it also provides for Transmit Power Control (TPC). I was under the impression that it's an FCC requirement for 5Ghz 802.11a Wifi devices. Here, it appears to be working as expected. I see messages like "Limiting TX power to 27 (30 - 3) dBm as advertised" in the kernel logs of my linux devices. Is TPC not well supported? edit: Whoops, I think TPC isn't really that interesting, and I'm confusing it with DTPC which is Cisco-proprietary.
- ajsnigrutin 6y ago
  But if your apartment is large, and you need coverage in your bathroom at the other side of it, you need more power.... this can't be automated, and manufacturers prefer higher range to users calls to support and helping them raise the power manually (especially when compared to an old AP, which had that range).
jefftk 6y ago
Yes! Compare a highway to a subway at rush hour. The road will be full of cars while the track will be empty most of the time, but the track will be carrying many more people per minute than the road due to more efficient allocation.
- wtallis 6y ago
  This analogy provides the argument for packet aggregation and maybe for for centralized packet scheduling (as on cell networks), but I don't see how it works for anything related to transmit power.
AnthonyMouse 6y ago
> The reason the ISM bands look so "hot" or busy on a spectrum analyzer is exactly because they're a "free for all." It's a classic tragedy of the commons: everyone keeps "shouting" at max volume to be heard and there's no coordination between operators and users of different services. This would be a lot more believable if the unlicensed spectrum wasn't already under low regulatory limits on power levels. You can always come up with some kind of system that will extract a little more efficiency out of things, but the reason most things use maximum power is that "maximum power" is already low enough that you can barely provide decent coverage from an access point on one side of your apartment to a device on the other. The reason the unlicensed spectrum is busy it that it's busy. Because there isn't enough of it. And the reason licensed spectrum isn't as busy is that incumbents buy more spectrum than they strictly need because it's a mechanism of excluding competitors.
- high_priest 6y ago
  There is an odd misconception in public, that "wireless" means full connection through two walls of rebar filled concrete... If you think that you can have pleasant, modern, net surfing experience without an AP in each room, then you can't say you know much about radio communications.
  - brokencode 6y ago
    Surfing the internet is a pretty low bar for WiFi networks, and has been easily passed for 10+ years. The fact is that wireless signals do penetrate walls, and putting an access point in every room would probably do more harm than good in terms of increasing interference.
  - posguy 6y ago
    WiMAX delivered a pleasant, modern experience without an AP in each room when that was operating at 2.5Ghz in the US, one tower would provide the coverage you describe for 2/3rds of a mile in any direction. Sadly, this 250+Mhz chunk of spectrum is now held by T-Mobile who uses only 40% to 60% of this spectrum for LTE and 5G coverage. There is plenty of spectrum left over to double the size of the 2.4Ghz ISM band used for WiFi, but the FCC has let Sprint/T-Mobile mispurpose this 2.5Ghz/2.6Ghz spectrum that was licensed for educational use only (explicitly for educational institutions to use for educational purposes like inter-building wireless links for campus TV stations).
grahamburger 6y ago
This is pretty much true, but with a catch - wifi is contention based. If two access points are close enough to hear each other's transmissions and they are operating on the same channel they will share that channel's bandwidth. Wifi was designed this way for exactly this reason, and it's probably why wifi still kind-of works even in large apartment buildings.
8K832d7tNmiQ 6y ago
You couldn't blame customers either, because you should consider that an average Joe doesn't have any time to think all about that and only know the bare basic of just plug-and-play. Furthermore, the IEEE spec itself has no standardised protocol to automatically adjust signal power between devices, which is an oversight in their side.
dheera 6y ago
> But no one is incentivized to do take action unilaterally. Maybe the FCC could incentivize people? Pay people $100/month to use Ethernet only. Hand out beamforming routers. Too many people are still stuck on b/g/n routers, which are a big part of the shouting culprit.
SulfurHexaFluri 6y ago
An alternative solution is to line the floors and roof of your apartment block in RF blocking material so only your wifi exists within it. Causes problems for phones not on the wifi network I guess but maybe its worth it.
shrewduser 6y ago
what if we started embedding wifi absorbing mesh into outer walls i wonder?
- hypertele-Xii 6y ago
  Looks to cost about USD 5..10 per m^2 [1]. Not a huge lot, maybe 500..1000 USD for all the walls of a small flat. There is the problem of also blocking cellular connectivity, though. [1] https://www.alibaba.com/showroom/faraday-cage-price.html https://www.alibaba.com/showroom/faraday-cage-price.html
bayindirh 6y ago
> Here's an example: in a typical apartment block, each resident runs their WiFi access point at full power. In any one apartment, there's a ton of interference from neighboring units. If everyone coordinated and reduced their WiFi power to just what was necessary to cover their unit, it would result in less interference and higher net data rates for everyone. But no one is incentivized to do take action unilaterally. There's a lot of assumptions here. First of all None of my wireless access points except a single range extender has transmission power settings. In that case, the setting is ganged for both 2.4GHz and 5GHz radios. So, I can't take this action unilaterally even if I want to do. Second, wall thicknesses and home geometries are very different across the world. Both my and my family's houses have very thick walls and tall storage units which effectively double the wall thickness so, with a relatively small house, I can't have reliable wireless everywhere at home even with two access points. I could increase coverage with more, less powerful access points but it needs recabling in a small, packed house which is not feasible. If I want to use range extenders with wireless repeating, trying to reduce wireless power becomes moot. This house runs on ADSL and the phone lines are at very strange places so both houses are effectively legacy systems with very small wiggle room. So, what's the solution?
- ghayes 6y ago
  FWIW, I don't think OP was necessarily saying that is a problem that needs a solution, so much as it's an explanation for the relative noise seen by GP. That said, it would be interesting to see coordination between access points in neighboring networks.
throwaway189262 6y ago
Eh it's debatable but I don't think this is entirely accurate. WiFi is very good at maintaining maximum transmission rates. High power is needed when doing stuff like QAM64 over the air. If wifi was louder than it needed to be, you wouldn't have to be mere feet away from the router to get maximum speed. Wifi bands are saturated because there's so little spectrum for a widely used service. Everyone has multiple wifi transmitter in their house yet there's only enough spectrum for three non-overlapping channels. Imagine there was enough spectrum for 30-40 wifi channels. There would be hardly any overlap and everybody would have better range. Maybe 500-1000 feet line of sight.
kalleboo 6y ago
> If everyone coordinated and reduced their WiFi power to just what was necessary to cover their unit, it would result in less interference and higher net data rates for everyone Our apartment is short and long, and the fiber comes in at one end. So of course we put the WiFi AP at the end of the apartment where the fiber comes in, and it needs to be at full power to reach the other end. Of course, now the person on the other side of the wall will be blasted with signal. A planned network from a provider would instead have 2-3 APs spread out through the middle of the apartment at a low power. But that costs 2-3 times more, plus now you have to drill through the walls to wire them (which we can't do as we're renting). There's a lot more difference between the usage of the ISM band and the licensed bands than "if everyone just lowered their power a bit it would be great". Since ISM band usage can't be planned to the same extent, it should have MORE spectrum than the planned bands, not less.
jjoonathan 6y ago
> This central planning maximizes the efficiency of the network. On one hand I see unused bandwidth*time, on the other I see applications that want to use more bandwidth and can't because of the obscene monetary cost. So no, the central planning clearly does not maximize efficiency. It does maximize the efficiency with which the telecom oligopoly removes the money from our wallets, though. I'll grant it that.

by sinak 6y ago

Reason077 6y ago

> "If everyone coordinated and reduced their WiFi power to just what was necessary to cover their unit, it would result in less interference and higher net data rates for everyone. But no one is incentivized to do take action unilaterally." This is something that needs to be fixed in future WiFi specifications and enforced via device certification. You're lucky if a typical WiFi base station operator understands how to set channels, let alone adjust TX power levels. People expect to be able to plug in a base station and have it "just work", so coordinating with other nearby stations to optimize spectrum usage, minimize TX power, etc is something that needs to be automatic.

jcelerier 6y ago
> People expect to be able to plug in a base station and have it "just work", so coordinating with other nearby stations to optimize spectrum usage, minimize TX power, etc is something that needs to be automatic. ... isn't it ? my internet box is from something like 2014 and is able to choose the less used wifi band automatically.
- danielheath 6y ago
  Can it choose to transmit quietly to avoid swamping nearby devices, or does it run the antenna at maximum transmit power?
- reaperducer 6y ago
  It won't reduce its power to make nice with the neighbors.
  - alacombe 6y ago
    Power usage is based on the worse-case attenuation scenario, the last thing ISP want are call asking why wifi don't work good in the bedroom if the router is on the other side of the apartment / house. Thus transmitting at max allowable power is the best solution.
    - wtallis 6y ago
      > Thus transmitting at max allowable power is the best solution. Transmitting at the max allowable power is the selfish and dumb solution. It isn't the best solution, in a world with multiple overlapping WiFi networks. It isn't even a Nash equilibrium.
      - pseudo0 6y ago
        Why do you think it isn't a Nash equilibrium? Any actor unilaterally choosing to transmit at lower power is going to experience worse signal quality, even if it's only marginally worse in some cases.
        wtallis 6y ago
        > Any actor unilaterally choosing to transmit at lower power is going to experience worse signal quality, even if it's only marginally worse in some cases. Yes, your received signal to noise ratio for that transmission will be somewhat decreased, and that might (or might not) hurt data throughput meaningfully. But it also means that your transmissions are causing less interference for your neighbor(s), and as a result your neighbor's equipment will not have to send as many retransmissions that potentially interfere with your own communications. It's a second-order effect, but also one that's proportional to how many neighbors you have in range that are trying to use the same slice of spectrum. So it's entirely possible that by unilaterally shouting less, you cause a significant reduction in wasted airtime that benefits both sides (though probably benefiting your neighbors more than you, depending on where your priorities lie between throughput and latency). It's not always a zero-sum game. In general (at least for WiFi), it's better to worry about airtime as the scarce resource rather than focusing on bytes per second. For fixed-rate wired networking, transmit time and bytes delivered are exactly proportional, but a variable-rate shared wireless medium decouples the two.
londons_explore 6y ago
Ummm... All WiFi devices adjust bitrate dynamically... For a given amount of data to be transmitted, adjusting bitrate up and freeing the channel quicker is equivalent to using a lower power for more time. Either way the disadvantages to other spectrum users are equal.
- wtallis 6y ago
  > For a given amount of data to be transmitted, adjusting bitrate up and freeing the channel quicker is equivalent to using a lower power for more time. It's not an exact equivalence. It is often possible to reduce transmit power without having to also significantly reduce bitrate. See eg. https://blog.linuxplumbersconf.org/2014/ocw/proposals/2439 https://blog.linuxplumbersconf.org/2014/ocw/proposals/2439
  - londons_explore 6y ago
    Shanon says that it is an exact equivalence, provided transmit power is >> thermal noise (it is)... If in real world devices that isn't the case, that's a shortcoming of the devices or protocol.
    - wtallis 6y ago
      Well, obviously in the real world, devices do not have unbounded transmit rates. But you can get pretty damn close to the transmitter. The Shannon limit isn't the only relevant limit, and is no reason to dismiss out of hand an entire class of optimizations that do help in the real world. (Also, even if your equipment is capable of hitting the Shannon limit, I'm not convinced that transmitting at the highest power level is going to be optimal for multi-party communications with geographically distributed APs and stations. The information channel between my neighbor's AP and his laptop is neither identical to nor completely separate from the information channel between my AP and my laptop.)
    - kortilla 6y ago
      > If in real world devices that isn't the case, that's a shortcoming of the devices or protocol Yes, welcome to the real world. There isn’t any protocol/hardware in use that scales up bandwidth with signal indefinitely.
wtallis 6y ago
The current situation is particularly disappointing when you realize that a lot of WiFi devices have been capable of adjusting TX power on a per-packet basis (per frame, really) at least as far back as 802.11n hardware. So your router should never be shouting at your laptop that's in the same room, even if it would use full transmit power to reach a device in the attic/basement/yard.
- Talanes 6y ago
  >at least as far back as 802.11n hardware. This made me realize how long it's been since I actually bought a router. The last time I was shopping around, getting 802.11n significantly narrowed the options.
  - wtallis 6y ago
    I'm impressed. The only good router I have left from that era has several Ethernet ports burned out, and the rest have too little storage and RAM to accommodate a recent OS with features like IPv6 support. And those are purchases from an era where 802.11n support was a given but dual-band 802.11n support was still reserved for more high-end products.
abestic9 6y ago
For frequency use, this already happens with automatic channel selection for neighbours, and DFS for avoiding a regulated frequency as soon as a signature is detected. WiFi 6 presents more efficiency with at a higher layer with BSS coloring to mitigate crowded channels. But as you said, most consumer wireless access points are still shouting over each other by default and it needs to be in the specification because there's zero incentive for a manufacturer to "worsen" their RF performance. It's a pointless consumer market IMO, most people don't need a Wireless LAN. Mobile carriers already provide Internet access to thousands of devices with just a handful of radios over several city blocks, but pricing means many homes end up standing up their own emitters for exactly the same purpose. Now we see bickering like this over what should be a far better coordinated EM spectrum. Worth note, most business/enterprise gear, which typically gets installed professionally, usually defaults to adjusting TX power automatically because more often than not it benefits the RF environment.
- kbar13 6y ago
  people very often need to setup their own WAP because cellular providers sell metered connections on the order of GB/month, whereas comcast (the most prevalent ISP in america) meters at TB/month. in addition, not every device currently has the radio / components necessary to receive cellular data also there's the limitation that cellular providers often don't allow tethering (or more generally data access outside of the device the sim card is slotted in)
  - abestic9 6y ago
    What I was getting at but forgot to include in my comment. Unfortunately it’s still a distant dream of mine that all carriers, fixed or mobile, would simply provide a dumb pipe billed based on max throughput and nothing more.
bronco21016 6y ago
... and to make matters even worse the solutions being marketed for fixing a lot of these problems are... MORE ACCESS POINTS! Every time a friend tells me about getting a mesh system to cover dead zones in their place I cringe at the thought of more 2.4 GHz blasting everywhere. 99% of the time the problem can be solved by better placing their current access point, whether that means moving their ISP provided router/AP, or installing a standalone AP and disabling whatever they're currently using for WiFi. I don't really know the answer to fixing the issues but it seems to me it's not technical, it's better information about placing the devices. End users just want it to work but don't have the time to learn how to best do that. ISP installers are not incentivized to care either, install as cheap and quickly as possible and get out. Mesh definitely isn't the answer though. It's the anti-answer.
- ipython 6y ago
  But it’s part of the answer isn’t it? As I understand it the answer in general is more, smaller access points each with less tx power. My wish would be that those mesh extensions wouldn’t then rebroadcast the signal at max 2.4ghz power but then you’d be pilloried by ignorant YouTube reviewers who rank solely on “how many bars at max distance” In most cases I feel your best position is in the ceiling at the center point of the house. I did that myself but at significant cost - fishing cat5 thru walls and ceilings and repositioning the incoming wires to the basement. 99.9% of users will never take that approach.
  - bronco21016 6y ago
    That could be true. However, it's better to use wired backhaul than more WiFi for the backhaul. Commercial locations do many access points with smaller broadcast area but use copper to bridge everything together. You're right about the location aspect though. 99% of people will not be bothered. How do we change that? The ISPs could be incentivized to do higher quality install work perhaps? I'm not sure what the answer is. The eruption in popularity of pro-sumer installs using gear like Ubiquiti gives me some hope that slowly people will see the way. I've installed UAPs at 5 homes now over the last 6-7 years. Zero support calls.
oasisbob 6y ago
What about 802.11h? In addition to defining DFS, it also provides for Transmit Power Control (TPC). I was under the impression that it's an FCC requirement for 5Ghz 802.11a Wifi devices. Here, it appears to be working as expected. I see messages like "Limiting TX power to 27 (30 - 3) dBm as advertised" in the kernel logs of my linux devices. Is TPC not well supported? edit: Whoops, I think TPC isn't really that interesting, and I'm confusing it with DTPC which is Cisco-proprietary.
ajsnigrutin 6y ago
But if your apartment is large, and you need coverage in your bathroom at the other side of it, you need more power.... this can't be automated, and manufacturers prefer higher range to users calls to support and helping them raise the power manually (especially when compared to an old AP, which had that range).

jefftk 6y ago

Yes! Compare a highway to a subway at rush hour. The road will be full of cars while the track will be empty most of the time, but the track will be carrying many more people per minute than the road due to more efficient allocation.

wtallis 6y ago
This analogy provides the argument for packet aggregation and maybe for for centralized packet scheduling (as on cell networks), but I don't see how it works for anything related to transmit power.

AnthonyMouse 6y ago

> The reason the ISM bands look so "hot" or busy on a spectrum analyzer is exactly because they're a "free for all." It's a classic tragedy of the commons: everyone keeps "shouting" at max volume to be heard and there's no coordination between operators and users of different services. This would be a lot more believable if the unlicensed spectrum wasn't already under low regulatory limits on power levels. You can always come up with some kind of system that will extract a little more efficiency out of things, but the reason most things use maximum power is that "maximum power" is already low enough that you can barely provide decent coverage from an access point on one side of your apartment to a device on the other. The reason the unlicensed spectrum is busy it that it's busy. Because there isn't enough of it. And the reason licensed spectrum isn't as busy is that incumbents buy more spectrum than they strictly need because it's a mechanism of excluding competitors.

high_priest 6y ago
There is an odd misconception in public, that "wireless" means full connection through two walls of rebar filled concrete... If you think that you can have pleasant, modern, net surfing experience without an AP in each room, then you can't say you know much about radio communications.
- brokencode 6y ago
  Surfing the internet is a pretty low bar for WiFi networks, and has been easily passed for 10+ years. The fact is that wireless signals do penetrate walls, and putting an access point in every room would probably do more harm than good in terms of increasing interference.
- posguy 6y ago
  WiMAX delivered a pleasant, modern experience without an AP in each room when that was operating at 2.5Ghz in the US, one tower would provide the coverage you describe for 2/3rds of a mile in any direction. Sadly, this 250+Mhz chunk of spectrum is now held by T-Mobile who uses only 40% to 60% of this spectrum for LTE and 5G coverage. There is plenty of spectrum left over to double the size of the 2.4Ghz ISM band used for WiFi, but the FCC has let Sprint/T-Mobile mispurpose this 2.5Ghz/2.6Ghz spectrum that was licensed for educational use only (explicitly for educational institutions to use for educational purposes like inter-building wireless links for campus TV stations).

grahamburger 6y ago

This is pretty much true, but with a catch - wifi is contention based. If two access points are close enough to hear each other's transmissions and they are operating on the same channel they will share that channel's bandwidth. Wifi was designed this way for exactly this reason, and it's probably why wifi still kind-of works even in large apartment buildings.

8K832d7tNmiQ 6y ago

You couldn't blame customers either, because you should consider that an average Joe doesn't have any time to think all about that and only know the bare basic of just plug-and-play. Furthermore, the IEEE spec itself has no standardised protocol to automatically adjust signal power between devices, which is an oversight in their side.

dheera 6y ago

> But no one is incentivized to do take action unilaterally. Maybe the FCC could incentivize people? Pay people $100/month to use Ethernet only. Hand out beamforming routers. Too many people are still stuck on b/g/n routers, which are a big part of the shouting culprit.

SulfurHexaFluri 6y ago

An alternative solution is to line the floors and roof of your apartment block in RF blocking material so only your wifi exists within it. Causes problems for phones not on the wifi network I guess but maybe its worth it.

shrewduser 6y ago

what if we started embedding wifi absorbing mesh into outer walls i wonder?

hypertele-Xii 6y ago
Looks to cost about USD 5..10 per m^2 [1]. Not a huge lot, maybe 500..1000 USD for all the walls of a small flat. There is the problem of also blocking cellular connectivity, though. [1] https://www.alibaba.com/showroom/faraday-cage-price.html https://www.alibaba.com/showroom/faraday-cage-price.html

bayindirh 6y ago

> Here's an example: in a typical apartment block, each resident runs their WiFi access point at full power. In any one apartment, there's a ton of interference from neighboring units. If everyone coordinated and reduced their WiFi power to just what was necessary to cover their unit, it would result in less interference and higher net data rates for everyone. But no one is incentivized to do take action unilaterally. There's a lot of assumptions here. First of all None of my wireless access points except a single range extender has transmission power settings. In that case, the setting is ganged for both 2.4GHz and 5GHz radios. So, I can't take this action unilaterally even if I want to do. Second, wall thicknesses and home geometries are very different across the world. Both my and my family's houses have very thick walls and tall storage units which effectively double the wall thickness so, with a relatively small house, I can't have reliable wireless everywhere at home even with two access points. I could increase coverage with more, less powerful access points but it needs recabling in a small, packed house which is not feasible. If I want to use range extenders with wireless repeating, trying to reduce wireless power becomes moot. This house runs on ADSL and the phone lines are at very strange places so both houses are effectively legacy systems with very small wiggle room. So, what's the solution?

ghayes 6y ago
FWIW, I don't think OP was necessarily saying that is a problem that needs a solution, so much as it's an explanation for the relative noise seen by GP. That said, it would be interesting to see coordination between access points in neighboring networks.

throwaway189262 6y ago

Eh it's debatable but I don't think this is entirely accurate. WiFi is very good at maintaining maximum transmission rates. High power is needed when doing stuff like QAM64 over the air. If wifi was louder than it needed to be, you wouldn't have to be mere feet away from the router to get maximum speed. Wifi bands are saturated because there's so little spectrum for a widely used service. Everyone has multiple wifi transmitter in their house yet there's only enough spectrum for three non-overlapping channels. Imagine there was enough spectrum for 30-40 wifi channels. There would be hardly any overlap and everybody would have better range. Maybe 500-1000 feet line of sight.

kalleboo 6y ago

> If everyone coordinated and reduced their WiFi power to just what was necessary to cover their unit, it would result in less interference and higher net data rates for everyone Our apartment is short and long, and the fiber comes in at one end. So of course we put the WiFi AP at the end of the apartment where the fiber comes in, and it needs to be at full power to reach the other end. Of course, now the person on the other side of the wall will be blasted with signal. A planned network from a provider would instead have 2-3 APs spread out through the middle of the apartment at a low power. But that costs 2-3 times more, plus now you have to drill through the walls to wire them (which we can't do as we're renting). There's a lot more difference between the usage of the ISM band and the licensed bands than "if everyone just lowered their power a bit it would be great". Since ISM band usage can't be planned to the same extent, it should have MORE spectrum than the planned bands, not less.

jjoonathan 6y ago

> This central planning maximizes the efficiency of the network. On one hand I see unused bandwidth*time, on the other I see applications that want to use more bandwidth and can't because of the obscene monetary cost. So no, the central planning clearly does not maximize efficiency. It does maximize the efficiency with which the telecom oligopoly removes the money from our wallets, though. I'll grant it that.