TDMA Engine Error

GNU Radio
1

I am trying to use the attached three files (posted by John M. in
an
earlier post
http://lists.gnu.org/archive/html/discuss-gnuradio/2013-02/msg00050.html
)
to work on TDMA in Gnuradio. The only difference is that I am using
GPSDO
kit, instead of external PPS/REF Clock. When I run tdma_radio.grc, I get
the following error. Could someone please comment how can I fix the
issue?

linux; GNU C++ version 4.6.3; Boost_104601; UHD_003.005.000-26-gb65a3924

– Opening a USRP2/N-Series device…
– Current recv frame size: 1472 bytes
– Current send frame size: 1472 bytes

UHD Warning:
The recv buffer could not be resized sufficiently.
Target sock buff size: 50000000 bytes.
Actual sock buff size: 1000000 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.rmem_max=50000000

UHD Warning:
The recv buffer could not be resized sufficiently.
Target sock buff size: 50000000 bytes.
Actual sock buff size: 1000000 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.rmem_max=50000000

UHD Warning:
The send buffer could not be resized sufficiently.
Target sock buff size: 1048576 bytes.
Actual sock buff size: 1000000 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=1048576
– Detecting internal GPSDO… Found a Jackson Labs GPS
– found
– Setting references to the internal GPSDO
– Initializing time to the internal GPSDO
– 1) catch time transition at pps edge
– 2) set times next pps (synchronously)
– 1) catch time transition at pps edge
– 2) set times next pps (synchronously)
Traceback (most recent call last):
File “/home/s/tdm/tdma_radio.py”, line 255, in
tb = tdma_radio(ampl=options.ampl, radio_addr=options.radio_addr,
args=options.args, rate=options.rate, tx_gain=options.tx_gain,
rx_gain=options.rx_gain, rx_freq=options.rx_freq,
samp_per_sym=options.samp_per_sym,
max_arq_attempts=options.max_arq_attempts,
guard_interval=options.guard_interval, arq_timeout=options.arq_timeout,
num_slots=options.num_slots, slot_interval=options.slot_interval,
initial_slot=options.initial_slot, dest_addr=options.dest_addr,
lead_limit=options.lead_limit, port=options.port, freq=options.freq)
File “/home/s/tdm/tdma_radio.py”, line 70, in init
freq=freq,
File “/home/s/.grc_gnuradio/tdma_hier.py”, line 76, in init
self.tdma_engine =
precog.tdma_engine(initial_slot,slot_interval,guard_interval,number_of_slots,lead_limit,link_speed)
File “/usr/local/lib/python2.7/dist-packages/precog/tdma_engine.py”,
line
100, in init
self.set_tag_propagation_policy(extras_swig.TPP_DONT)
NameError: global name ‘extras_swig’ is not defined

I have Extras installed. Thanks

–

Best Regards,

Sam

2

File “/home/s/tdm/tdma_radio.py”, line 70, in init
freq=freq,
File “/home/s/.grc_gnuradio/tdma_hier.py”, line 76, in init
self.tdma_engine =

precog.tdma_engine(initial_slot,slot_interval,guard_interval,number_of_slots,lead_limit,link_speed)

File “/usr/local/lib/python2.7/dist-packages/precog/tdma_engine.py”, line
100, in init
self.set_tag_propagation_policy(extras_swig.TPP_DONT)
NameError: global name ‘extras_swig’ is not defined

Looks like an import got removed from that file, but I dont think its
needed.

try changing this trouble line to

self.set_tag_propagation_policy(gnuradio.extras.TPP_DONT)

Or if that doesnt work

from gnuradio import extras
self.set_tag_propagation_policy(extras.TPP_DONT)

-josh

3

On Fri, Apr 26, 2013 at 10:15 AM, Josh B. [email protected] wrote:

self.set_tag_propagation_policy(extras_swig.TPP_DONT)

Or if that doesnt work

from gnuradio import extras
self.set_tag_propagation_policy(extras.TPP_DONT)

-josh

Thanks that solved the problem. tdma_radio.grc ran without any error
with
output as follows:

UHD Warning:
The send buffer could not be resized sufficiently.
Target sock buff size: 1048576 bytes.
Actual sock buff size: 1000000 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=1048576
– 1) catch time transition at pps edge
– 2) set times next pps (synchronously)
– 1) catch time transition at pps edge
– 2) set times next pps (synchronously)

gr_fir_fff: using SSE

How can I use tdma_engine in my following FSK flow graph;

TX Flow graph:
File source —> Packet Encoder —> pack to unpack/chunks to symbol →
upsample by 8—> Freq Mod—> USRP

Lets say USRP sampling rate is 500k.

I want USRP to transmit for 1 second and then wait for 2 second (in
these
two seconds two other same type of transmitters would transmit)and this
process should continue. Can I do that? Where should I place this
“tdma_engine” block. And what would be the values for its parameters?

Thanks for the time.

–

Best Regards,

Sam

4

On Mon, Apr 29, 2013 at 12:53 PM, Sam mite [email protected]
wrote:

File “/usr/local/lib/python2.7/dist-packages/precog/tdma_engine.py”,

Thanks that solved the problem. tdma_radio.grc ran without any error with
– 2) set times next pps (synchronously)
Lets say USRP sampling rate is 500k.
Best Regards,

Sam

Any thoughts or comments on this, please. Anyone done this before?

–

Best Regards,

Sam