WiFi Data Rates on NanoNote and SDW823 ??

Jörg Conradt conradt at tum.de
Thu Jan 6 17:39:51 EST 2011


Hi everyone!

Thanks for the initial replies to my question regarding data transmission rates.

> David:
>> That are feasable datarates due Spetec is a b/g card so in fact they
>> should be higher up to (54Mb/s) but I guess the SDIO  is the bottle
>> neck that is halfing the theorical data rate.
>> Some one correctme if I'm wrong.

Yes, in theory 802.11bg provides up to 54Mb/s; however, this theoretical maximum is never reached in practice. Typically (and under ideal circumstances) you can achieve about 1/2 of that. TCP is a protocol that corrects errors and re-sends data; so here the throughput shall even be lower than on UDP (which is a non-correcting protocol). The web page however states higher numbers for TCP than for UDP. 

Even more surprising: My high-end laptop with a build-in PCI-WiFi device typically achieves around 15-20 Mb/s; and PCI is much faster than SDIO. So I would expect a much smaller number for NanoNote & SDW823... 

That is why I am doubtful about the numbers provided by qi-hardware.



> jirka:
>> How is the best way to test? (with what command and what output you need)

I don't know of a program to test throughput; however, what you can easily do is copy a large file from/to your local network. So e.g. use "scp" to copy a large file (several 100 Mbytes, such as a CD image) from the NanoNote to your local PC over wireless. Most implementations of "scp" show the data rate during transfer; otherwise simply measure the time required for upload and download and divide the size of your file (in BITS) by the time required (in seconds).
Make sure you "scp" from/to your local network; otherwise the bottleneck in communication might be your internet service provider ;)
If you can't scp for a first test you can also download a large file through your web-browser's build-in download manager, etc...


Again: thanks for the feedback to far - and I sure hope someone who already owns a NanoNote+SDW823 can provide some rough numbers!

Thanks a lot!

	Jorg



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