There are many 802.11 wireless networking standards. These standards are managed by the IEEE LAN/MAN Standards Committee (IEEE 802). These standards are constantly being updated over time. If a device is 802.11 compliant it means the device has gone through interoperability testing. A Wi-Fi trademark on the device box indicates the device has gone through interoperability testing and should be able to interoperate with all devices that have gone through the same testing.
802.11a
- First of the 802.11 wireless standards
- Operates in the 5Ghz frequency
- Less prone to interference from other devices that use the same frequency range
- Greater throughput than 802.11b, with speeds up to 54Mbps with theoretical range of 150 feet.
- Only dual band 802.11n and 802ac are backwards compatible with 802.11a
- Not commonly seen today.
802.11b
- Introduced at the same time as 802.11a
- With a throughput of up to 11 Mbps, it is slower than 802.11a.
- Maximum range of 300 feet which is a greater range than 802.11a.
- Uses the popular 2.4Ghz band so more likely to run into interference from other wireless devices like baby monitors, cordless phones, microwave ovens, and Bluetooth
802.11g
- Takes the best of 802.11a and 802.11b
- Up to 54 Mbps
- Range of up to 300 feet.
- Uses 2.4GHz frequency so it’s backward compatible with 802.11b devices. But this also means its still likely to run into interference from other wireless devices.
802.11n
- Implements MIMO (multiple input multiple output) where devices can make multiple simultaneous connections.
- Throughput of up to 600 Mbps
- Operates at 2.4 GHz and/or 5 GHz frequency
802.11ac
- 5 GHz
- Improves upon 802.11n by allowing up to 8 MIMO streams (compared to 4 streams in 802.11n)
- MU-MIMO: Gives WAP the ability to broadcast to multiple users simultaneously
- Up to 7 Gb/s throughput
Frequencies
802.11 technology operates on 2 frequency bands: 2.4 GHz and 5 GHz. Some 802.11 wireless standards use either of the bands and some, like 802.11n use both bands.
- 2.4Ghz
- More popular so it’s more likely to run into interference from other wireless devices such as baby monitors, cordless phones, microwave ovens, and Bluetooth
- 5Ghz
- Less prone to interference
Channels
If so desired, you can choose which channel of frequency to use. Channels are a grouping of frequencies which are assigned numbers by the IEEE. For example, Channel 1 is a 20 megahertz block of frequencies in the 2.4 GHz range, centered around 2412 megahertz. Some channels overlap with eachother. For example, channel 1 and channel 2 in the 2.4 GHz range slightly overlap. You want to choose channels that don’t overlap, so choosing channel 1, channel 6, or channel 11 would be ideal to prevent overlap.
The 2.4 GHz includes 14 channels, but only 1-11 are used in North America. But other places, like Japan, use all 14. Every channel is a different sub-frequency range through which communication is done.
Bandwidth
Bandwidth refers to the amount of frequency in use. 20 MHz, 40 MHz, 80 MHz, 160 MHz are common bandwidths.
- 802.11a uses a 20 MHz bandwidth
- 802.11b uses a 22 MHz bandwidth
- 802.11g uses a 20 MHz bandwidth
- 802.11n has the option of a 20 MHz or 40 MHz bandwidth (the 40 MHz bandwidth is 2 contiguous 20 MHz bonded channels)
- In 2.4 GHz, a 40 MHz channel uses much of the available bandwidth
- 802.11ac uses
- 40 MHz for 802.11n stations
- 80 MHz for 802.11 ac stations
- 160 MHz optional
| Standard | 802.11a | 802.11b | 802.11g | 802.11n | 802.11ac |
| Max Throughput | 54 Mbps | 11 Mbps | 54 Mbps | 100+ Mbps | 1+ Gbps |
| Max Range | 150 feet | 300 feet | 300 feet | 300+ feet | 300+ feet |
| Frequency | 5 GHz | 2.4 GHz | 2.4 GHz | 2.4 and 5 GHz | 5 GHz |
| Security | SSID, MAC filtering, WEP, WPA, WPA2 | SSID, MAC filtering, WEP, WPA, WPA2 | SSID, MAC filtering, WEP, WPA, WPA2 | SSID, MAC filtering, WEP, WPA, WPA2 | SSID, MAC filtering, WEP, WPA, WPA2 |
| Compatibility | 802.11a | 802.11b | 802.11b, 802.11g | 802.11b, 802.11g, 802.11n, 802.11a (in some cases) | 802.11a, 802.11b, 802.11g, 802.11n |
| Communication mode | Ad hoc or infrastructure | Ad hoc or infrastructure | Ad hoc or infrastructure | Ad hoc or infrastructure | Ad hoc or infrastructure |
| Description | 8 available channels, less prone to interference than 802.11b and 802.11g | 14 channels available in 2.4GHz. 3 non overlapping channels | Improved security enhancements. 14 channels available in 2.4Ghz. 3 non overlapping channels. | Same as 8082.11g but adds 5 GHz band that 802.11a uses. 802.11n can also make use of multiple antennas (MIMO) to increase its range and speed | Expands on 802.11n by adding streams, bandwidth, and higher speed in the 5 GHz band. Uses MU-MIMO and beamforming antenna technology to optimize wireless connections. |
