What is 802.11 and their friends.

WLAN(Wireless Lan) was invented in University of Hawaii, 1970, under the leadership of Professor Norman Abramson.The wireless network communicated using radios, without using phone lines making it easy to deploy over Hawaii islands.

Original WLAN hardware was used as an alternative to cabled network where cabling was impossible or difficult. The protocals of WLAN at that time was proprietary. Many companies and universities appealed to establish a set of protocals as industry protocals. In the end of the 1990s, IEEE 802.11(Wifi) came to satisfy the urgent need. Subsequent amendments such as 802.11a, 802.11b, 802.11g, 802.11n was published in the following years. Other proprietary protocals was then graduately replaced by 802.11 family.

The original 802.11 was ratified in 1997 specifies two raw data rates of 1 and 2 megabits persecond to be transmitted via radio.The frequency band was set at 2.4GHZ.

The 802.11a amendment was ratified in 1999 which uses the same core protocol as the 802.11 standard but the frequncy band is set at 5 GHz. The maximum raw data rate of 802.11a can achieve 54 Mbit/s.

The 802.11b amendment was ratified in 1999 also which has a maximum raw data rate of 11 Mbit/s and works at the frequence band of  2.4 GHz as same as the 802.11 legacy.

The 802.11g amendment was ratified in June 2003. This flavor uses the 2.4GHz band, too, but it can reach a maximum raw data rate of 54 Mbit/s. Because of its prominent performance, 802.11g standard swept the consumer world even before the standard was fully ratified.

The 802.11n amendment was ratified in 2009. The maximum raw data rate can achieve 300 Mbit/s, even 600 Mbit/s due to the intruction of MIMO(multiple-input multiple-output) technology.

Actually, when we say 802.11, it should be the base standard of 802.11 in1999. All subsequent released amendments are based on 802.11 in 1999. However, it is probably too academic to stick to this outside the working group that produces and developments the IEEE 802.11 family.

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