Evolution of IEEE 802.11
As Wi-Fi users, we should have heard about IEEE 802.11 more or less. But what does it exactly mean?
IEEE is the abbreviation of the Institute of Electrical and Electronics Engineers. 802 is a committee in the institute for networking standards, also known as the LMSC – LAN/MAN Standards Committee. The committee covers such a big family of standards that it needs to be divided into groups devoted to specific areas. Each group has its own number (the one following "802", separated by a dot), so 802.11 refers to the 11th group of committee 802, which develops the Medium Access Control (MAC) protocols and Physical Layer (PHY) specifications of wireless local area networks (WLANs). IEEE 802.11 has experienced several "amendments", as shown in Table 7.1.
Table 7.1. Generations of IEEE 802.11
| Version | Frequency Range (GHz) | Channel Bandwidth (MHz) | Rate (Mbit/s) | Modulation Method | Alias |
|---|---|---|---|---|---|
| 802.11a | 5 | 20 | 54 | OFDM1 | – |
| 802.11b | 2.4 | 22 | 11 | CCK2/DSSS3 | – |
| 802.11g | 2.4 | 20 | 54 | OFDM | – |
| 802.11n | 2.4, 5 | 20, 40 | 72-600 (MIMO4:4×4) | OFDM | Wi-Fi 4 |
| 802.11ac | 5 | 20, 40, 80, 80+80, 160 | 433-1733 (MIMO:4×4) | OFDM | Wi-Fi 5 |
| 802.11ax | 2.4, 5 | 20, 40, 80, 80+80, 160 | 60-2401 (MIMO:4×4) | OFDMA5 | Wi-Fi 6 |
OFDM: Orthogonal Frequency Division Multiplexing.
CCK: Complementary Code Keying.
DSSS: Direct Sequence Spread Spectrum.
MIMO: Multiple Input Multiple Output.
OFDMA: Orthogonal Frequency Division Multiple Access.