OFDM RX Script Recovery After Interference

GNU Radio
1

Hey list, another OFDM question.

I have this simple OFDM script I have used before and in between USRPs I
have VHF handheld radio I am using as an interferer (also have plenty of
attenuation, between USRPs it is about 30 dB and the handset is
attenuated
by 55 dB). So with interefering signal around -23 dBm in between the the
transmission 80 kHz channel which is at -32 dbm as according to my
handheld
Spectrum Analyzer, GNU Radio’s FFT plot on the RX side gives a
transmission
of -90 dB and an interference at -50 dB.

Whenever the handheld goes off, the receiver predictably loses the
transmitted message and freezes up or the scope goes blank. Depending on
the duration of the interference of the handheld (just a simple click of
the tx) usually causes the receiver to lock up and not receive/never
recover transmitted comms again.

So why does the RX never recover and how can this be mitigated? I am
still
learning OFDM so I am thinking this is related to the channel estimator,
is
my line of thinking correct?

Thanks for the help,

Jon

2

Thanks for responding. No, everything is from the master branch, other
than
I split the ofdm_loopback script into tx and rx scripts but the blocks
went
unchanged.

Jon

3

On 04/21/2014 09:02 PM, Jonathan F. wrote:

Whenever the handheld goes off, the receiver predictably loses the
transmitted message and freezes up or the scope goes blank. Depending on
the duration of the interference of the handheld (just a simple click of
the tx) usually causes the receiver to lock up and not receive/never
recover transmitted comms again.

So why does the RX never recover and how can this be mitigated? I am
still learning OFDM so I am thinking this is related to the channel
estimator, is my line of thinking correct?

The channel estimator holds no state, so I doubt that’s the problem. Are
you working off of master?

Martin