Re: Problems with Correlation Estimator in GNURadio

Hi!

Thanks for your reply.

While I'll work on installing and working with GRC 3.8, I was just
wondering will the over the air communication be bad enough to not even
receive a single correct packet? Is it to do with loop_bw for FLL, PFB
and Costas_Loop or the digital gain values (a multiply block for the
source signal) in RX? What is the logic behind setting of the loop_bw of
these blocks?

Thanks and Regards
SG

On 15/05/20 6:34 pm, Shruti Gupta wrote:
> Hi!
>
> I have been trying to use the packet communication examples under
> gr-digital in GNURadio(v 3.7.14.0) on ubuntu machines with LimeSDR
> Mini for over the air communication.  I am using the
> usrp_packet_tx.grc and uspr_packet_rx.grc  to transmit and receive
> BPSK modulated packets respectively. I have modified these examples
> for LimeSDR Mini by including LimeSDR source and sink blocks and
> setting up the parameters. Now, I am running TX on one machine and RX
> on another machine tuned to same frequency. However, when I keep the
> gain values for RX low since the distance between TX and RX is few
> feet and eliminating the possibility of RX saturation, the packets are
> not being detected, while for higher gain values packets get detected
> but the correlation start tags are tagged before the position of
> estimation tags. I am not too sure if that's how it is suppose to work.
>
> Moreover, even after being detected the packets are not decoded and I
> receive following message  on console:
>
> INFO: Parser returned #f
>
> I think this is due to either incorrect header decoding or incorrect
> packet detection which freezes the header/payload demux block in the
> flowgraph. Also, even for very few packets that are decoded, the
> header is incorrect so why does the packet even gets decoded? Is there
> a way to work around this problem? Can we use some other block for
> packet detection?
>
> Any suggestion or help is highly appreciated.
>
> Thanks in anticipation
> SG