802.11g is a standard (official)

The Register's Wireless LAN Channel

The IEEE yesterday finally turned the 802.11g 54Mbps WLAN from a specification to a standard, giving the technology its official blessing.

Final ratification was something of a formality, the 802.11g spec. having barely changed since last year, and the final draft was passed unchanged last month.

Indeed, that the ratification was widely expected is shown by the large number of announcements issued by 802.11g product makers early this week, albeit released under non-disclosure agreements, just in case.

The ratification should now see the release of firmware updates to bring existing 802.11g products, of which there a plenty thanks to the stability of the spec. over the last six months or so, to bring them to full compliance with the standard.

The industry body that oversees 802.11 adherence, the Wi-Fi Alliance, will now begin 802.11g compatibility testing in earnest.

The 802.11g standard describes WLAN raw transmission rates of up to 54Mbps in the 2.4GHz band. Actual data rates, once network protocol overheads have been taken into account are around 20Mbps. Local network conditions may reduce that further, as will the presence of 802.11b nodes. 802.11g uses orthogonal frequency division multiplexing (OFDM) transmission modulation techniques whereas 802.11b uses complementary code keying (CCK). The new standard specifies full support for CCK to ensure backward compatibility.

Some 802.11g makers have their own techniques - such as Intersil's Nitro - for improving 802.11g performance in mixed-standard networks, but these are not part of the standard and will generally only work where networks contain 802.11g products from the same vendor.

802.11g has had a rocky ride since its inception three years ago. The first draft was fixed in November 2001, but development of the spec. was delayed over wrangling between parties favouring OFDM (led by Intersil) and others touting PBCC (Packet Binary Convolutional Coding) modulation, developed by Texas Instruments. The spec. didn't stabilise sufficiently for chip makers to feel safe offering product until last year, with commercial kit emerging late in 2002.

In addition to 802.11g, the IEEE ratified the 802.11f working practice standard. Dubbed the Inter Access Point Protocol, 802.11f ensures interoperability between access points from multiple vendors to enable client roaming. ®

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The Register's Wireless LAN Channel