Hi everyone,
Does anyone know if there is any source code available for OFDM type
standards like 802.11a/g/n?
I’d appreciate it if anybody knows.
Thanks a lot,
Mohsen
That code does implement an 802.11b receiver, and a transmitter that is
very similar to 802.11b (since the USRP is limited by the USB bandwidth
it can’t really do real 802.11b - without doing some of the work in the
FPGA at least). However, that’s all DSSS using a DBPSK/DQPSK modulation
scheme - not OFDM (or even the 5.5Mbps and 11Mbps CCK data rates).
Perhaps with the USRP2 - which will be able to do full-bandwidth
802.11b/g someone will start that (perhaps I will even contribute to
such work…).
Doug
The BBN code is implementation of 802.11b which uses DSSS in its
physical layer.
hamed
Quoting Dimitris S. [email protected]:
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On Sep 11, 2008, at 11:26 AM, Mohsen Baratvand wrote:
Guy, all I need to do is changing some parameters such as preamble,
LTF, STF, modulation and etc of the OFDM transmitter and then send a
predefined pattern to the OFDM receiver, then estimate the channel.
So I’m not gonna pass all the information and data to PC via the USB
link. Just sending some report to my PC.
It’s conceivable that by putting the modulation in the FPGA, you could
get 802.11a OFDM modulation to work using the USRP – just send the
data across the bus. But no one has written such a firmware image yet
- – feel free! (Disclaimer: I have no idea whether an 802.11a modulator
would fit into the small FPGA on USRP1, and haven’t tried).
If you want to do modulation in the host, which doesn’t involve FPGA
coding and might allow you to use some of the existing OFDM code,
you’re going to be limited by the bandwidth of the USB – 8 MHz isn’t
really enough. If you used 8-bit mode to get 16 MHz of bandwidth AND
used one of the low bitrate encodings, high-SNR packets MIGHT get
received by a good receiver. I don’t know enough about 802.11’s use of
OFDM to decide. Maybe Kyle or Tom has a comment here.
- -Dan
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Guy, all I need to do is changing some parameters such as preamble, LTF,
STF, modulation and etc of the OFDM transmitter and then send a
predefined
pattern to the OFDM receiver, then estimate the channel. So I’m not
gonna
pass all the information and data to PC via the USB link. Just sending
some
report to my PC.
On Thu, Sep 11, 2008 at 1:52 PM, Douglas G. <