Re: [Discuss-gnuradio] How do YOU packet detect?

[Richard Bell]

Ah, after re-reading the Header/Payload Demux docs, I noticed the trigger port is optional. The block will trigger on tags connected to the input stream.

What seems like the best strategy to me now is this:

1) Detect the header with a correlator and add a tag at the start

2) Feed the output of the correlator into the input port of the Header/Payload Demux block

3) Process the out header port and generate a message that feeds into the message port of the Header/Payload Demux block

4) The Header/Payload Demux block then releases the corresponding number of payload samples through the payload port.

I haven't touched messages before so this should be interesting. I welcome any feedback or common pitfalls to avoid.

Rich

On Wed, Mar 4, 2015 at 10:54 AM, Richard Bell <address@hidden> wrote:

No I haven't. I was hoping to keep this a self contained grc radio, because it makes my life easier. I will look at the benchmark scripts though.

Thanks,

Rich

On Wed, Mar 4, 2015 at 9:58 AM, Marc Newlin <address@hidden> wrote:

Have you looked at the narrowband example scripts? The benchmark_[rx|tx].py scripts support packetized QPSK. 

On Wed, Mar 4, 2015 at 11:54 AM, Richard Bell <address@hidden> wrote:

Hi all,

As the subject states, how have you detected packets in your packet based gnu radio SDR?

The only example I have come across is Tom's OFDM packet detect in the digital examples folder. There, he uses an OFDM specific block to generate the trigger signal for the Header/Payload demux.

My use case is very basic. I have a QPSK radio that I am using to measure the performance of different source codes. What I want to do is transmit a file (USRP N210) from the Tx and on the Rx dump the received signal into a file only after detection of the start of the file. I don't want a lot of garabage data before the file actually starts. To stop the dump, I would be happy detecting an end of file condition or using a smart preamble with the file length specified. Doesn't matter to me.

If you have any advice for my case, I would appreciate that.

v/r,

Rich

_______________________________________________
Discuss-gnuradio mailing list
address@hidden
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio