OFDM

The 802.11a standard uses the same core protocol as the original standard and was the first of the 802.11 family to operate in the 5 GHz band. It uses a 52-subcarrier orthogonal frequency-division multiplexing (OFDM) with a maximum raw data rate of 54 Mbit/s, which typically yields a throughput in the mid-20 Mbit/s.

OFDM takes an RF channel, such as the 20 MHz channel often used in Wi-Fi, and instead of using a single carrier-frequency modulated by AM, FM, or other means, sets out a number of sub-carriers. 802.11ac used 52 data-carrying sub-carriers in a 20 MHz RF channel, while 802.11ax has 234.

Orthogonal frequency-division multiplexing is a method of data transmission where a single information stream is split among several closely spaced narrowband subchannel frequencies instead of a single Wideband channel frequency .

OFDM-based wireless LANs will be implemented in the 2.4GHz ISM band as well as the 5GHz band. OFDM WLANs provide very high data rates, resilience to multipath and extended operating range.