802.11a – the new Wireless Local Area Network standard of the future

A family of IEEE standards for wireless LANs was first introduced in 1997. The original 802.11 specification provides 1 or 2 Mbps transmission in the unlicensed 2.4GHz band using either a frequency hopping modulation (FHSS) technique or direct sequence spread spectrum (DSSS), also known as CDMA. Wi-Fi The 802.11b standard is rated at 11 Mbps in the 2.4GHz band, but delivers approximately 7 Mbps in practice. The Wireless Ethernet Compatibility Association (WECA) endorsed the DSSS 802.11b version, branding it "Wi-Fi" for Wireless Fidelity. Wi-Fi and 802.11b have thus become synonymous.

802.11a A faster 802.11a standard provides from 6 to 54 Mbps at 5GHz, but is not backward compatible with 802.11b. 802.11g A subsequent 802.11g standard provides up to 54 Mbps at 2.4GHz as well as backward compatibility with the slower 11b. Both 11a and 11g use Orthosonal Frequency Division Multiplex (OFDM) modulation to achieve the higher rates.

An 802.11 system works in two modes. In "infrastructure mode", wireless devices communicate to a wired LAN via access points. Each access point - and its wireless devices - is known as a Basic Service Set (BSS). An Extended Service Set (ESS) is two or more BSSs in the same subnet. RTX believes that the 802.11a will shortly be the dominant wireless LAN technology as the major teleoperators are pushing towards implementing 802.11a so they can utilise their DSL and CATV strategy.