The IEEE developed the 802.11 standard for wireless local area networks (WLANs). There are four specifications including 802.11, 802.11a, 802.11b, and 802.11g. Each 802.11 standard operates in a different GHz range and/or offers a different speed. 802.11 applies to wireless LANs and provides 1 or 2 Mbps transmission in the 2.4 GHz band using either frequency hopping spread spectrum (FHSS) or direct sequence spread spectrum (DSSS).
The 802.11a specification operates in the unlicensed 5GHz range and offers data speeds up to 54Mbps. The 5GHz range is not yet crowded so it offers advantages in speed over the 802.11b specification which uses the more crowded 2.4GHz range (which can interfere with cordless phones, microwaves, etc.). However, the range and speed of 802.11a are inversely related, which means that 802.11a offers a smaller, more targeted footprint than other 802.11 technologies. 802.11a uses a modulation scheme known as orthogonal frequency-division multiplexing (OFDM) versus the FHSS or DSSS. Most 802.11a products are not compatible with 802.11b or 802.11g products (although this is changing).
The 802.11b standard operates in the 2.4GHz range and offers a data speeds up to 11Mbps. 802.11b is the de facto standard for WiFi services because of its ubiquity in the market and low price (although 802.11g will soon become the prevailing standard). While slower than 802.11a, 802.11b is still as fast as 10BaseT Ethernet service. 802.11b uses direct sequence spread spectrum (DSSS) and complementary code keying (CCK) modulation. 802.11b was certified by the IEEE in 1999.
802.11g was approved on June 11, 2003 and offers data speeds up to 54Mbps and operates in the 2.4GHz and 5GHz range making it backward compatible with 802.11b. Even before the IEEE approval, it was clear the 802.11g would become the standard for WiFi services and leading manufacturers started to release products in early 2003. 802.11g uses OFDM modulation but, for backward compatibility with 802.11b, it also supports complementary code keying (CCK) modulation.
With all the current 802.11 wireless standards, there are questions about security, speed, range, interference, and price. FierceWiFi covers these issues and more, focusing on the business of 802.11 and the growth of the WLAN industry.
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