3 ms·

It's not an issue of SNR. Wifi isn't allowed to transmit when it detects another station is already transmitting - it has to wait for clean air. By reducing eve

by crote 3y ago

It's not an issue of SNR. Wifi isn't allowed to transmit when it detects another station is already transmitting - it has to wait for clean air. By reducing everyone's power level the competing transmitter disappears into the noise floor, freeing up air for you to transmit on. A weak-ish signal which can transmit 100% of of the time is better than a strong signal which can only transmit 5% of the time. In theory you could indeed all shout at once, but that breaks down when your conversation partner is way closer to the other shouter - no matter how loud you shout, your message will always be overpowered and will only get through when you wait until the other shouter is silent. That's why wifi chooses to listen first.

ssl-3 3y ago
It is a a simple issue of SNR. Even if we could somehow turn down all 2.4GHz transmitters (we cannot), that won't actually help -- it can never make things behave like 5GHz bands do. Relatedly, hypothetically increasing the transmit power of all 5GHz devices can never make it behave like 2.4GHz does. Walls will still attenuate the higher frequency more than the lower one, and this function of a wall is independent of transmission power. And Wifi devices are nowhere near as polite as you proclaim. They walk all over eachother all the time, for all kinds of reasons. (CCA improves this, but it isn't a magical antidote.) Furthermore, not all 2.4GHz transmitters are Wifi at all. There's (still) a ton of stuff in use on that ISM band, much of which has nothing at all to do with computers or Ethernet. A 2.4GHz video feed doesn't care about neighboring Wifi networks, for instance. It doesn't even have the ability to care. It just transmits video, using whatever modulation it uses to do that, without any regard at all for other users. There's a lot of reasons that 2.4GHz is completely trashed in many areas -- including such offenses as leaky microwave ovens. That's just how it is, and how it is likely to remain. Which sucks, but here we are anyway...

by crote 3y ago

ssl-3 3y ago

It is a a simple issue of SNR. Even if we could somehow turn down all 2.4GHz transmitters (we cannot), that won't actually help -- it can never make things behave like 5GHz bands do. Relatedly, hypothetically increasing the transmit power of all 5GHz devices can never make it behave like 2.4GHz does. Walls will still attenuate the higher frequency more than the lower one, and this function of a wall is independent of transmission power. And Wifi devices are nowhere near as polite as you proclaim. They walk all over eachother all the time, for all kinds of reasons. (CCA improves this, but it isn't a magical antidote.) Furthermore, not all 2.4GHz transmitters are Wifi at all. There's (still) a ton of stuff in use on that ISM band, much of which has nothing at all to do with computers or Ethernet. A 2.4GHz video feed doesn't care about neighboring Wifi networks, for instance. It doesn't even have the ability to care. It just transmits video, using whatever modulation it uses to do that, without any regard at all for other users. There's a lot of reasons that 2.4GHz is completely trashed in many areas -- including such offenses as leaky microwave ovens. That's just how it is, and how it is likely to remain. Which sucks, but here we are anyway...