Larger bandwidth channels: Bandwidth channels are part and parcel to spread-spectrum technology. Larger
channel sizes are beneficial, because they increase the rate at which data passes between two devices. 802.11n supports 20 MHz and 40 MHz channels. 802.11ac supports 20 MHz channels, 40 MHz channels, 80 MHz channels, and has optional support for 160 MHz channels.
More spatial streams: Spatial streaming is the magic behind MIMO technology, allowing multiple signals to be transmitted simultaneously from one device using different antennas. 802.11n can handle up to four streams where 802.11ac bumps the number up to eight streams.
MU-MIMO: Multi-user MIMO allows a single 802.11ac device to transmit independent data streams to multiple different stations at the same time.
Beamforming: Beamforming is now standard. Nanotechnology allows the antennas and controlling circuitry to focus the transmitted RF signal only where it is needed, unlike the
omnidirectional antennas people are used to.
