What is IEEE 802.11b?
IEEE 802.11b-1999 or 802.11b, is an amendment to the IEEE 802.11 wireless networking that extends throughput up to 11 Mbit/s using the same 2.4 GHz band. A related amendment was incorporated into the IEEE 802.11-2007 standard. 802.11 is a set of IEEE standards that govern wireless networking transmission methods. They are commonly use today in their 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac and 802.11ax versions to provide wireless connectivity in the home, office and some commercial establishments. Wi-Fi is an unofficial retronym for 802.11b.
802.11b is use in a point-to-multipoint configuration, wherein an access point communicates via an omnidirectional antenna with mobile clients within the range of the access point. Typical range depends on the radio frequency environment, output power and sensitivity of the receiver. Allowable bandwidth is share across clients in discrete channels. A directional antenna focuses transmit and receive power into a smaller field which reduces interference and increases point-to-point range. Designers of such installations who wish to remain within the law must however be careful about legal limitations on effective radiated power.
Some 802.11b cards operate at 11 Mbit/s, but scale back to 5.5, then to 2, then to 1 Mbit/s (also known as Adaptive Rate Selection) in order to decrease the rate of re-broadcasts that result from errors.
Channel | Center Frequency | Frequency Data |
1 | 2.412 GHz | 5 MHz |
2 | 2.417 GHz | 5 MHz |
3 | 2.422 GHz | 5 MHz |
4 | 2.427 GHz | 5 MHz |
5 | 2.432 GHz | 5 MHz |
6 | 2.437 GHz | 5 MHz |
7 | 2.443 GHz | 5 MHz |
8 | 2.447 GHz | 5 MHz |
9 | 2.452 GHz | 5 MHz |
10 | 2.457 GHz | 5 MHz |
11 | 2.462 GHz | 5 MHz |
12 | 2.467 GHz | 5 MHz |
13 | 2.472 GHz | 5 MHz |
14 | 2.484 GHz | 5 MHz |
Note: Channel 14 is only allowed in Japan, Channels 12 & 13 are allowed in most parts of the world.
Learn about IEEE 802.11
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