Hi everyone,
I want to implement a TDD system with three USRP2 and an IBM server with
three Ethernet cards. The scenario is one relay and two nodes exchange
data through the relay, I want them to transmit data in their fixed time
slot, it does not need to be too precise, about 100 milliseconds per
slot is OK. The question is:
- Can I achieve my goal with the current equipment?
- I want to use the time-stamp in UHD to precise control the time to
send and recv, but without external clock, does the UHD have to use the
external clock to get the time?
Thank you in advance!
–
Best regards,
Pan, Luyuan
On Sun, Apr 22, 2012 at 3:16 AM, Pan, Luyuan [email protected]
wrote:
Hi everyone,
I want to implement a TDD system with three USRP2 and an IBM server with
three Ethernet cards. The scenario is one relay and two nodes exchange data
through the relay, I want them to transmit data in their fixed time slot, it
does not need to be too precise, about 100 milliseconds per slot is OK. The
question is:
- Can I achieve my goal with the current equipment?
I’m pretty sure, yes. The 100 ms should be pretty easily achievable.
- I want to use the time-stamp in UHD to precise control the time to send
and recv, but without external clock, does the UHD have to use the external
clock to get the time?
No, you do not need an external clock for this. All time in the UHD
land is relative, so you should be able to say “send packet 100 ms
from now” without caring what absolute time ‘now’ is.
Tom
Hello,
Thank you so much for your reply. And I also read your presentation and
audio about “Stream tag” on the website of GnuRadio Conference 2011, I
want to know a few questions about it:
- I think you defined some auxiliary control information to make the
stream start or stop on desired time, but above the UHD/gr-uhd and has
nothing to do with UHD, did I misunderstand it?
- May I use the “stream tag” to achieve my goal of TDMA
system?(consider the precision andefficiency)
- If so, and as the time-stamp cannot get through the gr-uhd, whether
is it more convenient for me to use the “stream tag”? Or maybe I can
code in some higher level like python?
Any comment/suggestion is greatly appreciated, thank you~
–
Best regards,
Luyuan Pan
On 04/23/2012 08:14 AM, Nowlan, Sean wrote:
I don’t think you can do this from Python yet, but I could be wrong
about that.
Not yet, but here are the docs for it:
http://gnuradio.org/redmine/projects/gnuradio/wiki/BlocksCodingGuide#Stream-Tags
This branch has the python support:
https://github.com/guruofquality/gnuradio/tree/python_blocks2
-josh