Re: [Discuss-gnuradio] Packet Encoder-Decoder

[John Malsbury]

Jeff, Tom,

The packet framer/deframer is mostly identical to the stream-based one in GNU Radio proper.  It's not a bad starting point, but a more general implementation that could be configured for a variety of applications, codes, and frame formats would be very interesting.  I think this would be a substantial project that could probably stand on its own. GSoC?

As far as gr-mac is concerned, I'm happy to put in some time and accept contributions on the project so we can get it merged.  Is this task-force worthy?   Something we should just discuss on another mailing list thread?  Or is there a better way to proceed?

-John

On Thu, Oct 9, 2014 at 7:23 AM, Tom Rondeau <address@hidden> wrote:

On Wed, Oct 8, 2014 at 7:25 PM, Jeff Long <address@hidden> wrote:

Hi Thanasis,

1. The flow you showed could not have worked because Packet Decoder takes unpacked bytes. The graph should be:

File Source -> Encoder -> Packed-to-Unpacked -> Decoder -> File Sink

2. The payload length defaults to 512 if you leave it at 0, so a short file won't fill a packet.

Encoder:
1 Sample/Symbol, 1 Bit/Symbol, Payload length 1

Packed-to-Unpacked:
1 Bit/Chunk, MSB

That worked for me.

General question for others ... the encoder/decoder are part of GRC and haven't had any substantial work in a long time. Is this code meant to be used, or should people look at other blocks, or gr-mac?

- Jeff

Yes, the encoder/decoder pair are quite old and meant as examples as much as anything; definitely not the definitive way to do this.

gr-mac is a good place to look for alternatives. I really hope to see us fix up some of the gr-mac code and merge as much as possible back into GNU Radio. And when I say fix up, I mean that they way they've done stuff inside there was based off the legacy code they pulled it from, so there's some mix of stream, stream tags, and pdu stuff in there that could be smoothed out. But they were solving the general problem of getting the mac to work. I'd love to see things cleaned up a bit now.

Tom

 

On 10/08/2014 06:26 PM, Charles Alberton Herdt wrote:

I am seeing the same problem here while running some tests.
Anyone else has any thoughts?

Running gnuradio 3.7.5, installed with the build-gnuradio script on
Ubuntu 14.04.

Gnuradio

On Tue, Oct 7, 2014 at 6:18 AM, Thanasis Balafoutis
<address@hidden <mailto:address@hidden>> wrote:

    Hi,
    In the followning basic setup:
    File Source (Byte) ----> Packet Encoder (Byte) -----> File Sink (byte)

    My input file is just a "Hello World" message
    If the Repeat property of my file source is set to "No" the File
    Sink remains empty Why? Do I have buffering issues?
    If I set Repeat="yes" file sink seems to work, But when I insert a
    Packet Decoder:

    File Source ----> Packet Encoder ----->Packet Decoder -----> File Sink

    The output file is empty again!

    Thanks

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    Discuss-gnuradio mailing list
    address@hidden <mailto:address@hiddenorg>
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