Forum: GNU Radio Adding/recovering packet number using packet_utils python cl

Announcement (2017-05-07): www.ruby-forum.com is now read-only since I unfortunately do not have the time to support and maintain the forum any more. Please see rubyonrails.org/community and ruby-lang.org/en/community for other Rails- und Ruby-related community platforms.
Tarun T. (Guest)
on 2007-06-16 23:13
(Received via mailing list)
Hi,

I was wondering if we can add the packet number using current
packet_utils
python class.

When I look into the code, I see that we introduce the preamble, access
code, length of the packet, payoad with crc, and padding for usrp using
make_packet function. At the same time when I look into the pkt.py , I
see
that msg.to_string() is the whitened_payload_with_crc and msg.arg1() is
the
whitener_offset for unmake_packet function in packet_utils class.

Now, I understand that the preamble and access codes are removed by the
timing and frequncy sync blocks in the receiver (please correct me if I
am
wrong), but I could not understand where the packet length, attached
with
the transmitted packet, went or if it was present, how do I get that?

Well, if I add the packet sequence number in the transmitted packet, how
can
i recover the sequence number? is it possible with current packet_utils
python class or I need to write a new class for the same?

I would welcome any guidance over adding/recovering of packet sequence
number.

Thanks in advance.

~Tarun
UT Dallas
Dan H. (Guest)
on 2007-06-16 23:19
(Received via mailing list)
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Tarun T. wrote:
>
> Now, I understand that the preamble and access codes are removed by the
> timing and frequncy sync blocks in the receiver (please correct me if I am
> wrong), but I could not understand where the packet length, attached with
> the transmitted packet, went or if it was present, how do I get that?

A better way to put it is that the preamble is ignored altogether and
the access code is detected by the framer_sink, which then pulls off the
length field.

> Well, if I add the packet sequence number in the transmitted packet, how
> can
> i recover the sequence number? is it possible with current packet_utils
> python class or I need to write a new class for the same?

Why don't you just put the sequence number as part of the body of the
message and then you don't have to touch packet_utils?

- -Dan
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.7 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFGdDd1y9GYuuMoUJ4RAlR1AJwNcK5H5C5LckVfG7q8T3oi3dVG2QCggBf0
t94tNgy9vErHj0oB3zKK3L8=
=BHHj
-----END PGP SIGNATURE-----
This topic is locked and can not be replied to.