There are many 802.11 protocols. Since 1997, 38 agreements have been officially adopted, and on average, more than 2 agreements have been issued every year. These agreements are very numerous.
We often hear that WIFI1/2/3/4/5/6 correspond to a version of the protocol, which means that a major supplement to the protocol is carried out, and a new communication technology is often introduced into the protocol.
For example, HR-DSSS of WIFI1 in 1999 increased the speed from 1Mbps/2Mbps to 5.5Mbps and 11Mbps.
WIFI2 introduces frequency division multiplexing technology to increase the speed to 54Mbps. But WIFI2 is basically not used, because it uses a brand-new frequency band, 5G, and the previous devices all work at 2.4G, which makes the new WIFI2 basically impossible to promote.
Later, WIFI3 in 2003 solved this problem. It was almost the same as WIFI2, except that the frequency band was changed back to 2.4G.
In 2009, WIFI4 introduced MIMO technology, which can work in both 2.4G and 5G frequency bands, and the speed can reach 600Mbps.
In 2013, WIFI5 introduced MU-MIMO technology, which only works in the 5G frequency band, and the speed can reach 6.9Gbps.
In 2019, WIFI6 introduced OFDMA technology, and the speed can reach 14Gbps.
Of course, 802.11 has many other supplementary protocols. These protocols are like small supplements to a larger version, such as 802.11e QoS protocol, 802.11i security protocol, 802.11k radio frequency management (Roaming auxiliary) protocol, and 802.11h radar coexistence protocol. These are still relatively large enhancements. There are also some unusual protocols, such as the 802.11w management frame encryption protocol. 802.11aa video multicast transmission reliability enhancement protocol. 802.11s mesh protocol. 802.11v WNM BSS switching and enhanced power saving protocol. 802.11r fast roaming protocol.
All these supplementary agreements can be classified into the following categories:
- Frequency band supplement
The 802.11aj-2018 Chinese military band protocol works in the 45G frequency band, providing a bandwidth of up to 1080MHz, and the rate can reach 15Gbps.
The 802.11ah-2016 ultra-low frequency band protocol works at 755MHz-928MHz to obtain greater transmission distance and lower energy consumption. It uses MIMO-OFDM technology with a bandwidth of 16MHz and a maximum rate of 347Mbps. This agreement is tailor-made for IOT.
802.11af-2014 TV white space agreement. Utilize unused VHF and UHF frequency bands.
The 802.11ad-2012 ultra-high throughput protocol utilizes the 60GHz frequency band
802.11y-2008 USA 3650-3700MHz frequency band
802.11j-2004 Japan 4.9GHz-5GHz protocol
2. Network enhancement
Connection enhancement:
The 802.11aq-2018 pre-association protocol allows APs to broadcast information to unconnected devices
802.11v-2011 (Wireless Network Mangement) (WNM). Fast BSS switching protocol.
802.11r-2008. Roaming is enhanced.
802.11k-2008. Radio measurement.
802.11h-2003. Radar coexistence agreement.
802.11d-2001. Added country information.
Security enhancement
802.11z-2010 TDLS
802.11w-2009 introduced PMF (Protected Management Frame)
802.11i-2004 defines WPA2 and RSN
3. Application enhancement
Video transmission enhancement:
The 802.11aa-2012 video transmission protocol introduces GCR and SCS mechanisms to enhance the reliability of broadcast packets, and refines the VI and VO queues.
Qos：
802.11ae-2012 Qos priority management frame protocol
802.11e-2005. Qos transfer protocol.
4. Network expansion
The 802.11ak-2018 Universal Link Protocol allows 802.11 networks and 802.3 networks to form a new 802.1Q network, providing VLAN or audio and video streaming services.
802.11s-2011 introduced the mesh network
Collaboration between 802.11u-2011 and external networks
802.11p-2010 car communication protocol
5. Improve network efficiency/capacity
The 802.11ai-2016 fast initial connection protocol introduces FILS, which allows APs to send 40-55bytes Discovery Frames at 6Mps speed and 20ms intervals, thereby reducing the need for STA proactive probes, reducing network usage, and improving the network The overall capacity.
6. Improve PHY rate
802.11 a/b/g/n/ac/ax defines the 6th generation WIFI. These protocols need to change the Radio layer, so hardware must be upgraded.
Ref:
https://wifiwizardofoz.com/802-11-standard-and-amendments/#:~:text=This%20article%20outlines%20the%20complete%20list%20of%20802.11,are%20revised%20and%20incorporated%20into%20a%20single%20document