Chapter · Wi-Fi
Sharing the air
Taking turns on one channel with a random backoff, stations that cannot hear each other, and the trade between a robust rate and a fast one.
- 07Sharing airtime5 minStations on one channel take turns. Each listens, waits a short gap, counts down a random backoff that freezes while the air is busy, and learns of a collision only when no acknowledgement comes back.
- 08When stations cannot hear each other4 minTwo stations can both reach an access point without hearing each other, and their frames meet at the access point. RTS and CTS ask the others to wait, and a much stronger frame can still get through.
- 09Robust versus fast4 minEach Wi-Fi frame goes out at a rate chosen for the signal, from slow and robust to fast and fragile. A slow station holds the air longer for every frame, and a link rate is never the speed of a download.
Start at 07 and read down — the order is the order things get easier in. Or take the one with your part in it; every article stands on its own, and links back to whatever it needs.