5 ms·

Agreed, but I don't know if anything can really be done for 2.4GHz at this point.

by skuhn 12y ago

jrockway 12y ago
Wifi's modulation schemes aren't the best for the real-world 2.4GHz spectrum. They work really well in the lab, and mildly well in the real world. Getting rid of Wifi and replacing it with something else could make unlicensed wireless networking more reliable. LTE-U seems like the way forward here, though it seems there are some industry barriers in the way. (If you make LTE chips and sell them all to cell phone carriers, and they tell you they don't like LTE-U, you probably won't be in a hurry to start selling LTE-U chipsets. Pure speculation.) That said, 5GHz Wifi does pretty well. There is a misconception that 5GHz doesn't go through walls, but that really has no scientific basis (2.4GHz and 5GHz radio signals are pretty much the same; 60GHz doesn't go through walls, but that's an order of magnitude higher frequency). The problem with 5GHz Wifi is that only some channels allow 2.4GHz-equivalent power levels, and access points are really dumb about auto-selecting them. So if you think 5GHz doesn't go through walls, try changing to a high-power channel. 149 is a good one to try, as it's high-power and has adjacent channels to steal for 80MHz 802.11ac. (The low channels are about 20x less powerful than the high channels. That's why people think 5GHz doesn't go through walls. Those low channels don't.)
- seanp2k2 12y ago
  Excellent tip re: power levels. FWIW though, if I'm reading this right, you can have high EIRP on most channels >= 52 : http://www.cisco.com/c/en/us/td/docs/wireless/access_point/channels/lwapp/reference/guide/lw_chp2/1140_chp.html http://www.cisco.com/c/en/us/td/docs/wireless/access_point/c... Little tidbits of knowledge like this are a big part of why I love HN. Now to go disable B/G on my home wifi and change the channel while wishing that home wifi routers shipped with low power-levels selected by default vs. the current situation of ISP-provided and out-of-the-box gear blasting out max power in every single apartment in my neighborhood, causing AirPlay to be unreliable across the living room.
- skuhn 12y ago
  That's interesting about the power levels per-channel. In my case, I actually WANT the not-going-through-walls experience. In an apartment (or hotel room), the goal is just to get as much coverage as you need, not to blanket three floors down. Smarter power level selection on APs (specifically consumer grade) would be nice. If all of your clients have acceptable signal strength, ratchet down, otherwise try ratching up, etc. If nothing else, it would be nice if manual control was possible (e.g. Apple removed transmit power selector from AirPort Utility). There's also the problem I mentioned with OS X (and possibly other clients) being biased towards 2.4GHz. I have to create separate SSIDs for 2.4 and 5 GHz at home, and some devices live on one and some on the other. Otherwise, I'll see occasional periods of really terrible performance with 2.4GHz, presumably because of interference (I can see 20+ SSIDs from my living room).
  - jrockway 12y ago
    Yes, clients are very bad about choosing the best connection for themselves. Access points can work around this by delaying probe responses on 2.4GHz relative to 5GHz, or by doing full-on band-steering (though it has to know that the target device is 5GHz-capable, which is hard). Really, WiFi is a mess, and it's up to the access point to restore sanity if possible. You're sort of doing that by hiding 2.4GHz under another SSID. (I do the same thing at home. I have a couple of devices that are 2.4GHz only. I can't wait until I can finally turn that off.)
spyder 12y ago
pCell (if it really works): http://www.cnet.com/news/is-pcell-the-holy-grail-of-wireless-networking/ http://www.cnet.com/news/is-pcell-the-holy-grail-of-wireless...

Agreed, but I don't know if anything can really be done for 2.4GHz at this point.

by skuhn 12y ago

Agreed, but I don't know if anything can really be done for 2.4GHz at this point.

Wifi's modulation schemes aren't the best for the real-world 2.4GHz spectrum. They work really well in the lab, and mildly well in the real world. Getting rid of Wifi and replacing it with something else could make unlicensed wireless networking more reliable. LTE-U seems like the way forward here, though it seems there are some industry barriers in the way. (If you make LTE chips and sell them all to cell phone carriers, and they tell you they don't like LTE-U, you probably won't be in a hurry to start selling LTE-U chipsets. Pure speculation.) That said, 5GHz Wifi does pretty well. There is a misconception that 5GHz doesn't go through walls, but that really has no scientific basis (2.4GHz and 5GHz radio signals are pretty much the same; 60GHz doesn't go through walls, but that's an order of magnitude higher frequency). The problem with 5GHz Wifi is that only some channels allow 2.4GHz-equivalent power levels, and access points are really dumb about auto-selecting them. So if you think 5GHz doesn't go through walls, try changing to a high-power channel. 149 is a good one to try, as it's high-power and has adjacent channels to steal for 80MHz 802.11ac. (The low channels are about 20x less powerful than the high channels. That's why people think 5GHz doesn't go through walls. Those low channels don't.)

seanp2k2 12y ago
Excellent tip re: power levels. FWIW though, if I'm reading this right, you can have high EIRP on most channels >= 52 : http://www.cisco.com/c/en/us/td/docs/wireless/access_point/channels/lwapp/reference/guide/lw_chp2/1140_chp.html http://www.cisco.com/c/en/us/td/docs/wireless/access_point/c... Little tidbits of knowledge like this are a big part of why I love HN. Now to go disable B/G on my home wifi and change the channel while wishing that home wifi routers shipped with low power-levels selected by default vs. the current situation of ISP-provided and out-of-the-box gear blasting out max power in every single apartment in my neighborhood, causing AirPlay to be unreliable across the living room.
skuhn 12y ago
That's interesting about the power levels per-channel. In my case, I actually WANT the not-going-through-walls experience. In an apartment (or hotel room), the goal is just to get as much coverage as you need, not to blanket three floors down. Smarter power level selection on APs (specifically consumer grade) would be nice. If all of your clients have acceptable signal strength, ratchet down, otherwise try ratching up, etc. If nothing else, it would be nice if manual control was possible (e.g. Apple removed transmit power selector from AirPort Utility). There's also the problem I mentioned with OS X (and possibly other clients) being biased towards 2.4GHz. I have to create separate SSIDs for 2.4 and 5 GHz at home, and some devices live on one and some on the other. Otherwise, I'll see occasional periods of really terrible performance with 2.4GHz, presumably because of interference (I can see 20+ SSIDs from my living room).
- jrockway 12y ago
  Yes, clients are very bad about choosing the best connection for themselves. Access points can work around this by delaying probe responses on 2.4GHz relative to 5GHz, or by doing full-on band-steering (though it has to know that the target device is 5GHz-capable, which is hard). Really, WiFi is a mess, and it's up to the access point to restore sanity if possible. You're sort of doing that by hiding 2.4GHz under another SSID. (I do the same thing at home. I have a couple of devices that are 2.4GHz only. I can't wait until I can finally turn that off.)

spyder 12y ago

pCell (if it really works): http://www.cnet.com/news/is-pcell-the-holy-grail-of-wireless-networking/ http://www.cnet.com/news/is-pcell-the-holy-grail-of-wireless...