Packet Loss Rate/Bit Error Rate

GNU Radio
1

If someone has ever measured Quality of service of received data (using
any
modulation and daughter board but preferably RFX2400) in terms of packet
loss rate/Bit Error Rate (or any other metric) with USRP & GNU Radio
without
any error correction (ARQ,FEC) mechanism (but no problem if you have
with
error correction mechnism) then please share your results here.

Actually without and error correction mechanism, with FSK, I am getting
almost half of my data lost. I was thinking that it may be improved by
adding some error correction mechanism. Or this high data loss is
because of
some implementation errors…What do you say ???

Thaks

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2

kaleem ahmad wrote:

We have no idea what your actual setup is, so we have no clue whether or
not error correction will truly help you.

It’s like saying my computer crashed, and asking if a new hard drive
will help. Who knows, it all depends :slight_smile:

Some questions that might help:

  • are you using coax?

  • are you using antennas?

  • what kind of gain are you using?

  • what kind of physical conditions?

  • what bitrate are you using?

  • are you seeing underruns at your receiver?

  • George

3

I am using RFX2400 daughter boards,
VERT2450 antenna which I received with my USRP from ettus,
I have tried different bitrates from 40kbps - 100kbps but got same
results,
I am not observing any overrun or underrun,
I am working in office environment where I dont have any interference
(almost),
Gain = 0, but I have tried other values [0-20].

Thanks

George N. wrote:

error correction mechnism) then please share your results here.

  • George

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4

Actually without and error correction mechanism, with FSK, I am getting almost half of my data lost.

A 50% BER can be a sign that your bits aren’t making it through it
all. I would guess you have some issues other than just needing error
correction. I would check to make sure that there is not something
wrong with your set up.

Keep in mind that a receiver which randomly guesses bits should
achieve a BER of 40-60% because data of any kind ends up with a close
to equal distribution of high bits and low bits.

Jason

5

On Fri, Jul 25, 2008 at 09:45:55AM -0700, kaleem ahmad wrote:

I am using RFX2400 daughter boards,
VERT2450 antenna which I received with my USRP from ettus,
I have tried different bitrates from 40kbps - 100kbps but got same results,
I am not observing any overrun or underrun,
I am working in office environment where I dont have any interference
(almost),
Gain = 0, but I have tried other values [0-20].

Thanks

What version of GNU Radio are you using?

There is no FSK code in the trunk nor in the latest tarball. I
removed it long ago because the code that was there didn’t work and
there was no one maintaining it.

You can save yourself and the rest of us a lot of trouble by using the
latest code either from a tarball or the svn trunk. Since you appear
to be somewhat of a beginner, I suggest you start with a tarball:

http://gnuradio.org/trac/wiki/Download

Eric