An Overview of WLAN: System Requirements and Practical Devices for Mobile WiFi

WLAN systems today operate in the unlicensed 2.4 and 5 GHz bands and have benefited from the rapid evolution of the 802.11 standard – from 802.11b in 1999 offering CCK modulation with 20 MHz channel bandwidth (BW) at 2.4 GHz, to 802.11ac in 2012 featuring OFDM, MIMO, 80 MHz BW, 256 QAM, both at 2.4 and 5 GHz.