Re: [Discuss-gnuradio] How to reconfigure automatically the channel used to received data in USRPs

[Lebowski80]

Ok, thank you for your advice, I will try with interprocess communication.

Regards


Nick Foster-4 wrote:
> 
> Short answer: You cannot open a new USRP instance to reconfigure an
> already-running USRP instance. You must reconfigure the existing instance.
> 
> The best advice I can give is that only one flowgraph can be operational
> per
> USRP device. In your setup, USRP#1 will run a single flowgraph with a
> source
> and/or sink, USRP#2 will run a single flowgraph with a source and/or sink,
> and USRP#3 will run a single flowgraph with a source and/or sink. If you
> wish to change the parameters of USRP#2 while it is running, rather than
> try
> to open a new USRP device in your benchmark_rxr.py flowgraph, use any of
> the
> standard interprocess communication methods to talk to your
> already-running
> USRP#2 script and reconfigure it as necessary.
> 
> --n
> 
> On Wed, Sep 7, 2011 at 9:31 AM, Lebowski80 <address@hidden>
> wrote:
> 
>>
>> Hello Nick,
>>
>> What do you mean? Actually I'm running RX and TX in two different
>> flowgraphs
>> on USRP1, the first one in usrp_spectrum_sense.py to look for a free
>> channel
>> (so the RX). In this script I also run benchmark_tx.py by the command p =
>> Popen('python benchmark_tx.py', shell =  True), then my second flowgrapgh
>> (the TX).
>>
>> My problem is that on USRP2 I want to reconfigure the RX channel by
>> python
>> (RX channel = 2484 MHz in the script benchmark_rx.py and RX channel =
>> channel received by USRP1 in the script benchamrk_rxr.py run by
>> benchmark_rx.py with the command p = Popen('python benchmark_rxr.py',
>> shell
>> =  True)).
>>
>> So I'm wondering if there exists the possibility to reconfigure the
>> parameters of a script in the same USRP (i.e. RX frequency channel) while
>> it
>> is running and if this is not possible what do people mean with "USRP
>> reconfigurability?"
>>
>> I really need an answer to understand the potentiality of my hardware,
>> thanks a lot!
>>
>> Regards
>>
>>
>>
>> Nick Foster-4 wrote:
>> >
>> > On Wed, Sep 7, 2011 at 3:27 AM, Lebowski80 <address@hidden>
>> > wrote:
>> >
>> >>
>> >> Hello everyone,
>> >>
>> >> Before to explain my problem I give some technical information about
>> my
>> >> hardaware. I'm using USRPs v1 and the boards integrated are XCVR2450
>> >> Transceivers.
>> >>
>> >> I'm using the script usrp_spectrum_sense.py in a USRP (called USRP1)
>> to
>> >> make
>> >> sensing in the ISM band, after a few seconds it sends to another USRP
>> >> (Called USRP2) a free sensed channel on the central frequency 2484
>> MHz.
>> >> USRP2 listens to the channel 2484 MHz through the script
>> benchmark_rx.py
>> >> and
>> >> it can properly receive the free ISM channel sent by USRP1. Then, I
>> want
>> >> to
>> >> use the USRP2 to receive data from another USRP (called USRP3) that
>> uses
>> >> the
>> >> script benchmark_tx.py.
>> >>
>> >> In the script benchmark_rx.py (used by USRP2) that listens to channel
>> >> 2484
>> >> MHz I want to run another script that I called benchmark_rxr.py that
>> >> waits
>> >> for data sent by USRP3 to be received in the free ISM channel sent by
>> >> USRP1.
>> >>
>> >> Relevant line of the code in the script benchmark_rx.py is attached
>> >> below:
>> >>
>> >> p = Popen('python benchmark_rxr.py', shell =  True)
>> >>
>> >> While this is the error that I get:
>> >>
>> >> usrp_open_interface:usb_claim_interface: failed interface 2
>> >> could not claim interface 2: Device or resource busy
>> >> usrp_basic_rx: can't open rx interface
>> >> Traceback (most recent call last):
>> >>  File "benchmark_rxr.py", line 153, in <module>
>> >>    main()
>> >>  File "benchmark_rxr.py", line 138, in main
>> >>    tb = my_top_block(demods[options.modulation],
>> >> mods[options.modulation],
>> >> rx_callback, options)
>> >>  File "benchmark_rxr.py", line 46, in __init__
>> >>    self.rxpath = usrp_receive_path.usrp_receive_path(demodulator,
>> >> rx_callback, options)
>> >>  File
>> "/opt/gnuradio/gnuradio-examples/python/usrp/usrp_receive_path.py",
>> >> line 65, in __init__
>> >>    self._setup_usrp_source(options)
>> >>  File
>> "/opt/gnuradio/gnuradio-examples/python/usrp/usrp_receive_path.py",
>> >> line 78, in _setup_usrp_source
>> >>    self.u = usrp_options.create_usrp_source(options)
>> >>  File
>> "/usr/local/lib/python2.6/dist-packages/gnuradio/usrp_options.py",
>> >> line 88, in create_usrp_source
>> >>    gain=options.rx_gain,
>> >>  File
>> >>
>> >>
>> "/usr/local/lib/python2.6/dist-packages/gnuradio/blks2impl/generic_usrp.py",
>> >> line 138, in __init__
>> >>    _generic_usrp_base.__init__(self, **kwargs)
>> >>  File
>> >>
>> >>
>> "/usr/local/lib/python2.6/dist-packages/gnuradio/blks2impl/generic_usrp.py",
>> >> line 63, in __init__
>> >>    except: raise Exception, 'Failed to automatically setup a usrp
>> >> device.'
>> >> Exception: Failed to automatically setup a usrp device.
>> >>
>> >> I read different post with this problem such as "Full duplex and half
>> >> duplex
>> >> does not work" and "help: cannot send after transport endpoint
>> shutdown"
>> >> but
>> >> I could not solve the problem yet. I need to close the reception in
>> 2484
>> >> MHz
>> >> channel for a new reception in another channel in USRP2. The only way
>> to
>> >> do
>> >> that seems to close the port manually (i.e. pressing ctrl+c) but I
>> want
>> >> to
>> >> do that by code. I tried different things before the line "p =
>> >> Popen('python
>> >> benchmark_rxr.py', shell =  True)" such as "id_process = os.getpid()"
>> and
>> >> "os.killpg(id_process, 2)", or by "tb.lock()" and "tb.unlock" and so
>> on,
>> >> but
>> >> nothing helped me, I keep obtaining the same error. I don't know what
>> to
>> >> do
>> >> else, can I change by code reception frequency in USRP2? Any advice
>> will
>> >> be
>> >> welcome, thanks a lot!
>> >>
>> >
>> > You need to run both RX and TX in the same flowgraph. You can't open
>> them
>> > in
>> > separate flowgraphs.
>> >
>> > --n
>> >
>> >
>> >
>> >>
>> >> Regards
>> >>
>> >>
>> >> --
>> >> View this message in context:
>> >>
>> http://old.nabble.com/How-to-reconfigure-automatically-the-channel-used-to-received-data-in-USRPs-tp32414957p32414957.html
>> >> Sent from the GnuRadio mailing list archive at Nabble.com.
>> >>
>> >>
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