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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."
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?
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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
The approved standard is tentative. The group will meet again next year to approve the real standard. This isn't coming to market for some time yet. register article
On the plus side, it will be usable in many countries rather than just North America like 802.11a (which is in a different spectrum) and it should be easier to share the RF section with 802.11b.
On the down side, it is in the same spectrum with 802.11b so you won't be bringing it up in parallel without interference and possible slow downs.
I haven't seen any predicted comparisons for cost, real world bandwidth vs. distance numbers or watts/byte numbers. These will be critical for determining which standard wins acceptance in various markets. No, I'm just kidding. The marketing departments of the manufacturers will choose which we use. I am guessing 'g' because it is later in the alphabet and clearly must be more advanced, but 'a' has that whole letter-grade thing going for it. Could go either way.
802.11c
802.11d
802.11e
802.11f
802.11h is already under development!
Disclaimer: I really don't know what any of this stuff is, I just searched on google.
The man who trades freedom for security does not deserve nor will he ever receive either. - Benjamin Franklin
FWIW, Atheros claims that 802.11a works up to 225 feet and provides more bandwidth than 802.11b at any range. Take it with a grain of salt since Atheros makes 802.11a chips, but it's still worth a read.
I believe that you are both right. There are bands for
both licensed and unlicensed. I belive there are 8(?) unlicensed bands, and 3(?) licensed. I don't have a reference handy, and don't feel like looking it up. Perhaps someone knows the exact numbers? Oh, and this would only apply in the US. Just as with current 802.11b, different countries reserve different numbers of frequencies.
I've sometimes wondered what kind of effect it would have on these wireless networks if I put up a 1500 Watt omnidirectional propagation beacon on 2.4 GHz. I have an FCC license that authorizes me to use the 2390-2450 MHz frequency band. If I remember correctly, Part 15 devices must accept interference from licensed users and may not cause interference to licensed users.
Mea navis aericumbens anguillis abundat
This is true in the US, but strangely enough there are other countries in the world - many of them (e.g. Europe) have only licensed spectrum at 5 GHz. Please remember that the US != The World....
.11g. 802.11a uses 5 GHz. Neither uses 900 MHz, of course.
802.11b uses 2.4 GHz, as does