802.11g Approved By IEEE 54 mb/s on 2.4 gigahertz

wavecentral writes "IEEE just approved the 802.11g as the new standard in a vote late Thursday. This enables data transfer rates of up to 54 megabits per sec and works on the 2.4 gigahertz band that 802.11b uses. This in turn makes it compatable and operable between the offical standard." Ewann also writes: "By mid-2002 we should be seeing products based on this technology. Unlike 5 GHz 802.11a, 802.11g is backwards compatible with the huge installed base of 802.11b products. Cool stuff if you want to wirelessly stream video and music in your home. More info on 0211-planet."

Comments

Article on eetimes

[morcheeba]

more info at eetimes

The final proposal calls for two mandatory modulation/access schemes of complementary code keying (CCK) used in 802.11b and the newly allowed orthogonal frequency division multiplexing (OFDM) used in the 5-GHz 802.11a standard. As an option, however, the 802.11g proposal allows for the inclusion of Intersil's original CCK-OFDM scheme, which supports rates of 6 to 54 Mbits/s, and of TI's PBCC-22 (packet binary convolutional coding) method, which supports rates up to 33 Mbits/s.

Three possible coding schemes? This will either drive the price up (to support all three), or lead to incompatibilities when only portions of the spec are implemented. I'd love to find out more... is there some negiotiation in the protocol too see what coding methods are supported?

Not just backwards compatibility

[90XDoubleSide]

802.11a has very short range, which is why Apple did not implement it in its new AirPort products, but chose to wait out for 802.11g, which will offer the same range and backwards-compatibility. As was mentioned, the products probably won't be available until mid-2002. From an ITWorld article: "The range supported from access point to client in an 11M-bit/sec network is about 300 feet. The shorter, wider radio waves in a 5GHz 802.11a LAN, while offering more capacity, transmit only about 90 feet."

Countering interference

[Walter Bell]

One of my co-workers has been following 802.11g through the standards approval process and he said that 802.11g is designed to "fall back" to using a part of the spectrum reserved specifically for this protocol if the rest of the available frequencies are congested. Although this will help little if there are several wireless networks in a dense area (cf. downtown Chicago), it will help a lot for networks like my home 802.11b setup, which starts dropping packets when somebody fires up the microwave, cordless phone, or X-10 video transmitter. These devices should not interfere with the reserved area of spectrum and thus a moderate level of network performance will be maintained.

It just goes to show that sometimes when the FCC serves the interests of their large corporate customers (who undoubtedly begged for the reserved 802.11g frequencies for obvious business reasons), consumers benefit. Not usually, but sometimes.

~wally