this post was submitted on 11 Mar 2024
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Technology

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[–] [email protected] 32 points 8 months ago (4 children)

Sounds like bad WiFi design not building design.

[–] [email protected] 52 points 8 months ago (2 children)

I could imagine that those concave metal roof sheets reflect the electromagnetic waves all over the place, causing tons of interference...

[–] [email protected] 8 points 8 months ago (1 children)

Are they not equipped to deal with that? You'd think large metal surfaces are pretty common, so it'd be a bigger issue if so.

[–] [email protected] 9 points 8 months ago (1 children)

Well, straight metal surfaces are a whole different story from concave metal surfaces.
The former causes interference in a line in one specific direction, with roughly the width and height of said metal surface.
Concave metal surfaces on the other hand, can easily blast a whole room, depending on how concave they are.

And I'm a bit out of my water here, but I believe, modern WiFi does try to

  1. direct its EM-waves towards the recipient, rather than send in all directions.
  2. adjust the strength of its signal, so that it reaches the specific recipient and not that much more beyond that.
  3. resolve multipath issues, so where a recipient can be reached in two or more ways, e.g. directly and through a reflecting metal surface. It can attempt to do so with 1) and 2).

But yeah, ultimately this can't be an exact science. Recipients move around. Interferences move around. You still need additional EM-waves to advertise yourself as WiFi to disconnected devices. A reflecting interference may be situated behind a recipient, where you do need to send signals to.

And of course, no one expects ~~the Spanish Inquisition~~ Google's house of mirrors, where any misdirected EM-wave will interfere with everything else in the room. That just ramps up any imperfections in WiFi by a lot...

[–] [email protected] 1 points 8 months ago

This design looks like you could get more than one roof segment involved, too, especially if there's a lot of traffic. I didn't know that they actually manage spacial relationships like that, but I guess it makes sense. I suppose that's why the extra antennas on some models.

In theory, a radio reflection off something non-flat can be a treated a bit like an extra point source. My curved tea kettle won't mess with wi-fi, because a reflection off it just looks like a straight but lossy path that's the sum of the distances involved. If something's a wavelength across weirder things can happen, of course, but wi-fi is in relatively short bands for the most part, and there's more than one so it can just switch if it's in a dead spot. A wi-fi signal will also be modulated pretty fast, though, so now you have to think in frequency space as well, I'm not sure how that works.

Google's hipster building is on a scale that's very different from a kettle, but at least as complex geometrically, so maybe that's where the gap in access point design lies. They expect small distortions and big perfect reflections.

[–] [email protected] 7 points 8 months ago

Yeah I'm thinking that's most likely the problem.

[–] [email protected] 20 points 8 months ago (2 children)

Bad building layout could cause multipath issues though.

[–] [email protected] 16 points 8 months ago* (last edited 8 months ago) (1 children)

Shit where I work the cell service is terrible inside the building but the moment you walk outside the building it's perfect

Our building has a wavy metal roof and wavy metal siding

Edit: Spleling

[–] [email protected] 12 points 8 months ago

LoL mroe spleling.

[–] [email protected] 2 points 8 months ago

This is what mimo uses to speed things up.

[–] [email protected] 4 points 8 months ago

Yeah, whoever designed radio waves wasn't thinking about the potential for creative architecture!

[–] [email protected] 2 points 8 months ago

To put it more descriptively, when you do industrial scale WiFi, you're supposed to design out the network during the blueprint stage, then go through with a signal analyzer to map out the radio properties when it's time to install the telecom

You can put an access point in every room or every 30 feet, and tune them to work seamlessly without interference. You can do the same with cell signals too. They even make cables that are also the antenna - they're cut with gaps in the shielding, so you can get perfect coverage inside an iron maze if you wanted to

It's all just a matter of cost... It's not cheap, but a few million dollars is just a line item at that scale