Let's try to investigate the error messages you are receiving.
When
you run cdma_txrx.grc and you lower the SNR (the first slider) then the
receiver cannot anymore track/acquire the packet and a message appears
on the screen:
******* MESSAGE DEBUG PRINT ********
((packet_num . 711) (packet_len . 54))
************************************
******* MESSAGE DEBUG PRINT ********
((packet_num . 712) (packet_len . 54))
************************************
INFO: Detected an invalid packet at item 25668
******* MESSAGE DEBUG PRINT ********
#f
************************************
******* MESSAGE DEBUG PRINT ********
((packet_num . 714) (packet_len . 54))
************************************
******* MESSAGE DEBUG PRINT ********
((packet_num . 715) (packet_len . 54))
************************************
When the SNR is up again the receiver goes back to acquisition/tracking and recovers the remaining messages.
This is how the system is supposed to work.
BTW, the messages titled "******* MESSAGE DEBUG PRINT ********" are coming from the message debug block,
while the messages "INFO: Detected an invalid packet at item 25668" are coming from the packet_headerparser_b block.
------------
So far so good.
Now, if you want to run the cdma system with an actual usrp you should use the two SEPERATE files:
cdma_tx.grc and cdma_rx.grc
For this you can disable the fifo sink/source and enable the already present usrp blocks.
Suppose you do all these. Then you run the tx and the rx applications.
Now you are saying the what you see is a message like this:
Sgr::log :INFO: packet_headerparser_b0 - Detected an invalid packet at item 0
******* MESSAGE DEBUG PRINT ********
#f
************************************
Clearly the first line is coming from the block packet_headerparser_b0 and the other 3 from the message_debug block.
(why
is does the first log message have a different fromat than above? ie,
why does it start with "Sgr::log :"--I don't know ... )
Neither seems to be a surprise (according to the previous discussion).
So the question is why the application stops (DOES IT STOP?)
For this you have to help us a little bit.
Can you figure out which process/thread stops?
It is interesting that the error happens at the very first sample 0.
Can you run JUST the cdma_rx.py and report the messages you are seeing.
Also using a debugger can you identify the thread that hangs.
thanks