Module d'émetteur de Wifi de module de Cansec TA3220SSA-F IoT Wifi transparent à la commande

Years ago, 802.11n introduced some exciting technologies that brought massive speed boosts over 802.11b and g. 802.11ac does something similar compared with 802.11n. For example, whereas 802.11n had support for four spatial streams (4×4 MIMO) and a channel width of 40MHz, 802.11ac can utilize eight spatial streams and has channels up to 80MHz wide — which can then be combined to make 160MHz channels. Even if everything else remained the same (and it doesn’t), this means 802.11ac has 8x160MHz of spectral bandwidth to play with, vs. 4x40MHz — a huge difference that allows it to squeeze vast amounts of data across the airwaves.

To boost throughput further, 802.11ac also introduces 256-QAM modulation (up from 64-QAM in 802.11n), which basically squeezes 256 different signals over the same frequency by shifting and twisting each into a slightly different phase. In theory, that quadruples the spectral efficiency of 802.11ac over 802.11n. Spectral efficiency is a measure of how well a given wireless protocol or multiplexing technique uses the bandwidth available to it. In the 5GHz band, where channels are fairly wide (20MHz+), spectral efficiency isn’t so important. In cellular bands, though, channels are often only 5MHz wide, which makes spectral efficiency very important.