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Faster, Stronger 802.11b
stoney27 writes: "Looks like U.S. Robotics has doubled the speed of 802.11b plus increased the range. See link on MacCentral." You'll need upgraded equipment at both the base-station and computer ends to get a boost in speed, but they claim compatibility with standard 802.11b.
Double the bandwidth! Does that mean I have to use two pringle cans as antennas? Once I pop, the file transfers don't stop!
I design user interfaces for a free network management application,
... when you post all your stories twice.
my other sig is a 500 page novel
Of course. We've just doubled the bandwidth, now we can read all Slashdot stories twice.
So we poor .EU people (where 802.11a is not allowed as the 5.4 GHz band is not free) can get a speed bump as well? I only wonder at what range the 22Mbps will work? 50m? 25m?
These chips double 802.11b speeds by functioning full duplex. The drawback however, is that this requires category 5 air.
;)
Not all offices and homes fulfill this requirement. Location plays an important role: in the city you'll most likely not be able to communicate full duplex. In suburbs you'll have a fair chance if you're not too close to the city. In rural area's you'll most probably always have full duplex.
You can communicate at 22 Mbps over short distances using category 4 air, but when the peers are more than a few meters apart, category 5 air becomes a must.
Just something you might want to know before you buy these things..
Note: since this story seems a duplicate, I'll just duplicate my reply as well..
All of the 22Mbps 802.11 hardware coming out is based on the Texas Instruments ACX100 chip. TI was proffering this (their own) standard to become 802.11g, but lost out in the end. The chip is indeed fully backwards compatible with 802.11b.
There are going to be others putting out HW based on the ACX100 as well, Linksys for one. So well see how many people jump on the the bandwagon before 802.llg gets into the market.
The operating range for HW based on this chip will be larger. This is because the device can get a full 11Mbps signal with a signal to noise ratio half that of current HW. This means that at 11Mbps the range will be significantly larger. However at 22Mbps the range should be about the same as, perhaps slightly better than, current 802.11b systems.
The system uses the same channels as 802.11b and AFAIK doesn't use up more channels than 802.11b (ie 3 orthogonal channels in the US).
The chip is also all CMOS so power consumption should be somewhat better than todays 802.11 stuff as well.
That's all I know, hope this illuminates the issue...
Since this whole article/discussion is irrelevant anyway, let's all take a look at yahoo's great pic of the day, for some unintentional humor instead.
Shutting down free speech with violence isn't fighting fascism. It IS fascism!
11g is really 11a-style OFDM at 2.4 Ghz rather than the 5 Ghz band. There would be two (at least) 11g modes: a compatibility mode whereby OFDM packets and legacy 11b CCK packets coexist, and one which is "pure" OFDM at 2.4 Ghz.
... and these differences are quite small if you have a good 11a radio with a good antenna.
The compatibility mode adds a huge overhead to each transmitted packet. An 11g transmitter in this mode must first complete a legacy 11b RTS/CTS operation on the air which, if successful, is followed by the actual packet. Even if the actual packet were transmitted at nearly infinite bandwidth, the effective bandwidth you'd see on a connection would be quite low - think 10 Mb/s on average. That's not exactly chopped liver and its way better than legacy 11b, but it's definitely not 54 Mb/s.
There are suprisingly large differences between 11a products, even those using the exact same vlsi chips. There are two primary reasons: differences in choice of output power amplifier (or lack thereof) and differences in choice of antenna. You can deduce some of what's going on by looking at power and sensitivity ratings in manufacturers product specs. By the way, this also a great way to distinguish between 11b products as well.
Second generation 11a products have much better receiver sensitivity and output power than the first generation versions. And they do transmit through walls... although not concrete or metal or mirrors or some ceramics.
The main reason why 11b can reach farther than 11a in some situations is that 11b can ratchet down to 1 Mb/s whereas 11a is defined for rates from 54 down to 6 Mb/s (11g is identical to 11a in this regard). The difference in SNR and sensitivity needed at a receiver to pick out the 11a or 11g signal accounts for nearly all of the differences in range
Thus, 11g will have the same power, SNR, and receiver sensitivity challenges as 11a in the 5 Ghz band, but will also have a small boost in signal propagation efficiency in the lower band.
Don't get bamboozled by the hype about compatibility with 11b. Compatibility for sharing the channel does not imply that the radio properties of 11g are the same as 11b.
Most vendors are busy bringing out 11a+b base stations and NIC cards. 11g in compatibility mode looks like a nightmare, whereas 11g in "pure" mode looks like 3 more channels of high performance OFDM if you have an 11a radio that can tune to both the 5Ghz and 2.4 Ghz bands. Aside from the higher-power outdoor channels at 5.8, this provides 11 channels for OFDM (8 at 5 Ghz plus 3). And this means that a group of base stations in an AP-dense environment will certainly be able to find a clear channel.
I didn't say much about the PBCC-based 22 Mb/s products. PBCC is actually a clever design but is likely going to be overshadowed by OFDM at 5 Ghz (11a) and OFDM at 2.4 Ghz (11g variants).
15 minutes ago, I brought home a new Zyxel 316 Wireless starter kit. I just figured I check slashdot before I configured it, and now its obsolete. Great.
Wow. This post looks familiar.
Oh yeah, because I originally posted it here.
Only there, it had my name as the author of the post...
A hint: Please include credit for the original content if you are going to repost a comment. Otherwise it is called plagarism.