Hello All,
I'm trying for discontinuous transmission of random packets
to
exhibit *two state markov model(ON and OFF cycles).The states for
markov
model are generated by predefined transition matrix. I utilized the *
benchmark_tx.py example in digital section ,which has discontinuous
transmission for every 5 packets.
Currently, I made little modifications to the code so that for ON state
random packets are transmitted and for the OFF state, time.sleep
function is
performed. The program runs fine for* small burst of packets (1,2 or 4
packets for ON cycle)* but, if I transmit big burst of packets(10,15 or
20
packets for ON cycle) then OFF cycle is completely dead which causes in
continuous transmission.
Questions:
1. * I assume the flow-graph is still active even during the OFF
cycle(data is still processing through the GNU blocks)??*
-
2. Is time.sleep() function is an appropriate way to use for
OFF
cycles in my model ?? If not can anyone suggest me better way to break
the
transmission using GNU blocks ??*
-
3. Is there anyway to control the transmission at python level
by
using single or multiple flowgraph model or suggestion to implement any
new
block ??? *
- Multiple flowgraph Approach* :
- I tried to provide a two flowgraph model for ON and OFF
cycles;I
switch between the two depending on the markov state. *
- I tried to provide a two flowgraph model for ON and OFF
ON cycle flow -graph:
- packet modulator --------> modulator ----------> ampl ----------->
usrp
sink*
*OFF cycle flow-graph *
- packet modulator --------> modulator ----------> ampl
----------->null
sink* -
-
- Does my problem has anything to do with in band timestamp of
packets ???
- Does my problem has anything to do with in band timestamp of
-
It would be great if someone guide if I’m wrong in understanding GNU
Radio
architecture.Thanks in advance.
*Model : USRP 1 + RFX 2400 *
OS : Ubuntu 9.0.4
Regards
Venkat V. Patcha
Research Assistant
Electrical Engineering
Louisiana State University