Re: [Discuss-gnuradio] Transmitting a binary 'ones and zeroes' file for Bit Error Analysis

[Tom Rondeau]

rashi dixit wrote:
> Hello Everyone
>
> I am currently working on binary file transmission from one system to 
> another, but couldnt figure a way out yet.
>
> Using tx_voice.py when I send a binary file with just an arbitrary 
> stream of ones and zeroes, data is read and transmitted as packets 
> well. But unfortunately, on receival side on the retrieval of data, it 
> isnt written back into the file in the binary format as originally but 
> a combinations of bits are clubbed and expressed by incomprehensible 
> hashes and stars. So the data cant be deciphered.
>
> I tried using the GMSK modulation scheme. But the binary data chunks 
> are filtered out during transmission only....probably due to the 
> gaussian filter. Please check me out if I am wrong.
>
> Could anyone suggest a way for a ones and zeroes file to be 
> transmitted? My final aim is  to find the 'Bit error rate' of 
> transmission form one node to another.
>
> Also is there any way of comparing two binary files? I mean how should 
> one approach the bit error analysis keeping correlation in mind etc?
>
> Thanking you all
> Rashi Dixit

Rashi,

I'm not sue why you are using tx_voice.py for this. It seems to make 
more sense to use benchmark_tx.py and benchmark_rx.py in the /digital 
examples directory. This will modulate the bits with GMSK by default. 
Keep in mind, though, that you _want_ to modulate the data before 
transmitting it over the air.

The GNU Radio file sink/source write and read files as binary data, so 
the files will look like hashes and stars when viewed with a text 
editor. You can use gnuradio-core/src/utils/read_*_binary.m in 
Matlab/Octave to read these files.

However, I'm not sure you want to just compare the output file to the 
input file unless you also keep track of a packet number. If the header 
is missed or corrupted in the current implementation, the packet is 
completely dropped, which would completely screw up your calculations 
unless you can tell that a full packet has been lossed. Then, you have 
to decide how you want to handle the BER calculation due to one lost 
packet.

Tom