Re: [Discuss-gnuradio] GRC 3.6 / 802.11 a/g test signal

[Bastian Bloessl]

Hi,

On 04 Oct 2014, at 15:50, Ernest Szczepaniak <address@hidden> wrote:

> Hello,
> 
> First of all, much love for your reply (it made my day).
> 
> So i started with sent frame [2]. And my receiver gives some nice results:
> 
> - found OFDM symbol
> - aquired time synchronization
> - Shmidl/Cox says that there is no frequency offset (so it is good for no 
> noise frame)
> - SIGNAL field is modulated with BPSK 6 Mbps (correct) and it says that:
>    - rest of the data is modulated with BPSK 6Mbps
>    - coderate is 1/2
>    - 1 bit per carrier
>    - 364 octets of data (is that correct?)
>    - reserved field, parity bit and tail bits seems to be fine.
> 
> Further MAC decoding says that:
> - descrambler initial state is [0 1 0 1 0 1 1] (correct?)
> - 16 zeros in SERVICE field (7 for desrcambler synchro and 9 reserved - seems 
> to be correct)
> - according to standard this is a PNC Selection (PNCS) frame type with retry 
> ([0 0 0 1] in frame type field) is that correct?


my decoder says:

new mac frame  (length 360)
=========================================
duration: 00 00
frame control: 00 08 (DATA)
Subtype: Data
seq nr: 0
mac 1: ff:ff:ff:ff:ff:ff
mac 2: 23:23:23:23:23:23
mac 3: ff:ff:ff:ff:ff:ff
Hello World!Hello World!Hello World!Hello World!Hello World!Hello World!Hello 
World!Hello World!Hello World!Hello World!Hello World!Hello World!Hello 
World!Hello World!Hello World!Hello World!Hello World!Hello World!Hello 
World!Hello World!Hello World!Hello World!Hello World!Hello World!Hello 
World!Hello World!Hello World!Hello World!

It does not contain a LLC, just a MAC header. It is BPSK 1/2 encoded. I guess 
the initial scrambler state was 0b0101010 (=42) and it is a data frame.

Best,
Bastian


> 
> Best,
> 
> Ernest
> 
> 
> 
> W dniu 2014-10-04 11:16, Bastian Bloessl pisze:
>> Hi,
>> 
>> you can use gr-ieee802-11 [1] to generate WiFi frames. Just start the TX 
>> flow graph and pipe the output to a file.
>> I uploaded a frame (IQ data, no noise) [2] for you that you can use to get 
>> started.
>> 
>> I don’t use Matlab, so i don’t know how to import the data, but you can 
>> display the IQ samples with
>> 
>> od -fw8 frame.bin
>> 
>> There is also a GNU Radio script [3] that might be helpful.
>> 
>> Hope it helps,
>> Bastian
>> 
>> 
>> [1] https://github.com/bastibl/gr-ieee802-11
>> [2] https://www.ccs-labs.org/~bloessl/frame.bin
>> [3] 
>> https://github.com/gnuradio/gnuradio/blob/master/gr-utils/octave/read_complex_binary.m
>> 
>> 
>> 
>> On 02 Oct 2014, at 17:25, Ernest Szczepaniak <address@hidden> wrote:
>> 
>>> Greetings engi's!
>>> 
>>> I'm currently working on my masters (802.11 wlan receiver with
>>> MATLAB/USRPN210). After creating all the important stuff ie:
>>> 
>>> -symbol finder
>>> -time synchronization
>>> -coarse and fine frequency compensation
>>> -symbol demodulator
>>> -deinterleaver
>>> -Viterbi decoder
>>> -descrambler etc.
>>> -MAC layer decoding
>>> 
>>> i'm looking for any tested 802.11 a/g IQ signal for further research
>>> becouse live samples captured by USRP seem to have incorrect result's
>>> (wrong frame type MAC field, random MAC adress, CRC, parity bits etc).
>>> 
>>> And here comes my 1st question.
>>> 
>>> Is there any place where i can get some real, tested IQ wlan signal i
>>> a/g standard and full description (rate, coded data, adresses, included
>>> MAC fields)? Tried with Agilent Signal Studio but files are saved in
>>> .wfm encrypted format :(
>>> 
>>> I also found GRC beacon frames transmitter, written in GRC
>>> 
>>> http://rrsg.ee.uct.ac.za/members/jwamicha/gr-wlan.tar.gz
>>> 
>>> but due to having GRC 3.7 (where 'gnuradio-core' was repleaced with
>>> 'gnurdaio-runtime') i can't simply compile this file becouse of an
>>> error:
>>> 
>>> ---------------------------------------------------------------------------
>>> 
>>> checking for GNURADIO_CORE... configure: error: Package requirements
>>> (gnuradio-core >= 3) were not met:
>>> 
>>> No package 'gnuradio-core' found
>>> 
>>> Consider adjusting the PKG_CONFIG_PATH environment variable if you
>>> installed software in a non-standard prefix.
>>> 
>>> Alternatively, you may set the environment variables
>>> GNURADIO_CORE_CFLAGS
>>> and GNURADIO_CORE_LIBS to avoid the need to call pkg-config.
>>> 
>>> ---------------------------------------------------------------------------
>>> It seems that those binaries arent compatible with my GRC version :(
>>> 
>>> Any helpful guy to install this library and send me IQ signal of this
>>> beacon frame? (in any MATLAB readable format - simple file sink in GRC).
>>> 
>>> Looking forward for any reply.
>>> 
>>> Thanks
>>> 
>>> 
>>> _______________________________________________
>>> Discuss-gnuradio mailing list
>>> address@hidden
>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>> 
>> --
>> Dipl.-Inform. Bastian Bloessl
>> Distributed Embedded Systems Group
>> University of Paderborn, Germany
>> http://www.ccs-labs.org/~bloessl/
>> 
>> 
>>