Comment by motrm
4 years ago
This may not always be the case, fortunately! I recall the Broadcom Wi-Fi 7 chipset announcement[0] in April mentioned a dedicated scan core which may well offload the network searches to a separate part of the chip, freeing the AP connectivity core(s) from having to do other tasks for a second or two each minute.
Here's hoping it works as I understand it and other chipsets start doing similar things!
Supporting 802.11g means scans are send at 1Mbit. 802.11a bumps it to 6Mb/s, so not much better. This means that every time you want to send a beacon you have a pause equal to the duration it takes to send a packed at 1-6Mbit, not to mention scanning all the channels.
To do passive scanning you need to "be quiet" for sufficiently long to pick up beacons from other stations, so that is unlikely to help.
Because wifi is shared via time slicing don't you have to be quiet part of the time anyways?
Surely you can’t use the same antennae for two different operations at the same time…
The noise would be unsalvageable and you would lose packets, surely.
On different bands you can with basic filters. On the same band it would admittedly be tough (unless the band is super wide like the 6E band). It is done by radio repeaters for example but they do need big bulky filters, that kind of thing would not work on a laptop. But it is possible to transmit and receive on the same antenna at the same time, it's not a technical limitation. You just need a good enough filter.
I mean background scanning only has to be a read operation, shouldn't that make it simpler?
Also things these days often have multiple antennas.
Also for 2.4ghz I believe Bluetooth shares the same channels. I've noticed that my BT headphones reach longer in no-wifi/few wifi locations.