Wireless transfer rates

[Monkey muppet]

Every so often the Wifi transer rates creaps up

11mbps > 54mbps > 108mbps > 125mbps

how high can they go and why???

 

[Matthias99]

First off, the highest official standard (802.11a/g) is ~54Mbps. The "108Mbps" and higher ones are manufacturer-specific standards that only work with their equipment, and if you read the fine print it's usually "only in optimal configurations" or something like that (ie, if the two devices are like three feet apart and sitting inside a faraday cage ).

They're limited by the bandwidth of the signal and the speed of the sending/receiving equipment. The bandwidth they're allowed to use is fixed by the FCC (although you could subdivide it into more channels with better equipment, but that would basically be a whole new spec and no longer under 802.11), so the limitation then becomes how fast the sender and receiver can communicate. 802.11g is basically a high-speed version of 802.11b (which is why it's backwards compatible). Products that claim to increase bandwidth beyond that are usually doing it by switching into some super-high-speed mode when they detect a compatible device on the other end.

 

[Sahakiel]

Compression.

 

[Monkey muppet]

Originally posted by: Sahakiel
Compression.

Which brings me back to the original question - what is preventing the speeds from increasing??

You state compression - yet the technologies behind this are always being developed

 

[elecrzy]

noise, dispersion, interference, distortion, etc(look up the terms if you don't know)

 

[MadMan2k]

Probably broadcast power, as regulated by the FCC (or whichever org does this).

 

[RaynorWolfcastle]

actually the 108 mbps products do this by bonding two 54mbps channels. The way 802.11b/g are designed is that there are two independant "channels" in the spectrum. I'm not positive about the way they worked this out, but you can probably vary the carrier frequency slightly and you can only fit in two channels in the allocated bandwidth for these devices. Usually these two channels are there so that you can use your Wifi network without interfering with your neighbour's network. This is why the 108mbps is a bad idea generally as it pollutes the entire spectrum in that range.

Getting back to your original question, "upgrading speeds" is a multifaceted problem. While more bandwidth always helps, it's also a matter of exploiting it in a cost-efficient manner. Better modulation schemes, more sophisticated antennas, more sensitive analog electronics, and several other things allow you to increase the speed. Once there is enough progress a new standard generally emerges and you get a boost in speed. I think that 802.11n is the next standard coming up and it will be 100 mbps or better without using this channel bonding hack.