PHY, the physical layer of IEEE 802.11, has the following history of technology development and technical standards:
IEEE 802 (1997)
Modulation technology: infrared transmission of FHSS and DSSS
Operating frequency band: operating in the 2.4GHz frequency band (2.42.4835GHz, 83.5MHZ in total, divided into 13 channels (5MHZ between adjacent channels), each channel accounting for 22MHz. When the channels are used simultaneously, there are three non-overlapping channels [1 6 11 or 2 7 12 or 3 8 13])
Transmission rate: At this time, the transmission rate is relatively slow and the data is relatively limited. It can only be used for data access services, and the maximum transmission rate is 2 Mbps.
Compatibility: not compatible.
IEEE 802.11a (1999)
Modulation technology: officially introduced (OFDM) technology, namely orthogonal frequency division multiplexing (OFDM).
Operating frequency band: at this time, it operates in the 5.8GHz frequency band (5.725G5.85GHz, 125MHz in total, divided into five channels, each channel accounts for 20MHz, and adjacent channels do not overlap each other, that is, when the channels are used at the same time, these five channels do not overlap each other).
Transmission rate: when the transmission rate increases, it is 54, 48, 36, 24, 18, 12, 9, and 6. The units in this range are Mbps.
Compatibility: not compatible.
IEEE 802.11b (1999)
Modulation technology: expand IEEE 802.11 DSSS mode and adopt the CCK modulation method
Operating frequency band: 2.4GHz
Transmission rate: support different rates of 11 Mbps, 4.5 Mbps, 2 Mbps, and 1 Mbps
Compatibility: Start downward compatibility with IEEE 802.11
IEEE 802.11g (2003)
Modulation technology: introducing orthogonal frequency division multiplexing (OFDM) technology
Operating frequency band: 2.4GHz
Transmission rate: realize the maximum data transmission rate of 54 Mbps
Compatibility: Compatible with IEEE 802.11/IEEE 802.11b
IEEE 802.11n (2009)
Modulation technology: introducing orthogonal frequency division multiplexing (OFDM) technology + multiple input/multiple outputs (MIMO) technologies
Operating frequency band: 2.4G or 5.8GHz
Transmission rate: data transmission speed can be up to 300~600Mbps
Compatibility: Compatible with IEEE 802.11/IEEE 802.11b/IEEE 802.11a
The above is the historical process of the IEEE802 protocol, which is not difficult to find. This protocol includes both 2.4G and 5G frequency bands. Moreover, with the development of history and the constant revision of the protocol, the rate is developing upwards. At present, the theoretical maximum speed of the 2.4G band can reach 300Mbps, and the maximum speed recording of the 5G band can reach 866Mbps.
Summary: The protocols supported by 2.4GWiFi are: 11, 11b, 11g, and 11n.
The protocols supported by 5GWiFi are 11a, 11n, and 11ac.
The above is the knowledge explanation of WLAN Physical Layer PHY brought to you by Shenzhen Haidiwei Optoelectronics Technology Co., Ltd. Shenzhen Haidiwei Optoelectronics Technology Co., Ltd. is a manufacturer specializing in optical communication equipment products