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

From: Ernest Szczepaniak
Subject: Re: [Discuss-gnuradio] GRC 3.6 / 802.11 a/g test signal
Date: Mon, 6 Oct 2014 01:33:07 -0700 (MST)

Hi, much appreciate for your reply Bastian.

I have succefully found your frame.bin signal, forwarded by my USRP
(generated in MATLAB, received with Windows Network Monitor and wlan card). 

You were right. It is Data frame, 232323:232323 Source MAC and FFFFFF:FFFFFF
Destination MAC. 

Still dunno what's wrong. 

Could you please check my methodology??

1st OFDM symbol is carrying a SIGNAL field - it is decoded correctly (i
checked all rates with your grc wlan script)  - no problem here. 

2nd OFDM symbol is carrying Data. Assuming BPSK 1/2, it should carry 16 bit
SERVICE field, and 8 bits from FRAME CONTROL field (together - 24 uncoded

And my algorythm goes as follows (for 2nd OFDM symbol):

- OFDM demodulation (to get 48 complex data points)
- BPSK demodulation (to get 48 coded bits)
- de-interleaving (1st and 2nd permutation)
- Viterbi decoding ([133 171 poly] to get 24 uncoded bits)
- descrambling 

and if its correct way, i should get 24 bits of data (16x0 and 8 bits
depending on FRAME CONTROL paylaod) right?


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