Which IEEE 802.11 standard was the first to utilize OFDM?

The first IEEE 802.11 standard to utilize Orthogonal Frequency-Division Multiplexing (OFDM) is IEEE 802.11a. OFDM is a digital modulation technique that divides a signal into multiple smaller sub-signals that are transmitted simultaneously at different frequencies. This approach improves resistance to multipath interference and enhances data rate and capacity.

IEEE 802.11a was introduced to support high-speed wireless communication in the 5 GHz band, allowing for greater data rates and improved performance in environments with higher interference. It can achieve rates up to 54 Mbps. The use of OFDM in this standard marked a significant advancement in wireless networking technology compared to its predecessors, which employed different modulation methods like Direct Sequence Spread Spectrum (DSSS).

In the context of the other standards, IEEE 802.11b uses DSSS and operates primarily in the 2.4 GHz band. Meanwhile, IEEE 802.11g also utilizes OFDM but was developed later as a way to maintain compatibility with 802.11b while offering higher speeds. IEEE 802.11n further builds on these developments with Multiple Input Multiple Output (MIMO) technology but came after the initial implementation of OFDM in 802.11a