Re: [Discuss-gnuradio] precise transmit scheduling: GNUradio state-of-the-art?

[Chris Albertson]

Have you looked into real-time versions of the Linux kernel?
I've used real-time Linux to control devices at the microsecond
level. (We were generating pluses directly control a CCD
chip and move charge on the chip.)

I think you are going to have to find a way to combine gnuradio
and one of the real-time linux systems.  

Real time Linux is pretty easy to use. This has more info
and Google will turn up even more. 
http://www.linuxdevices.com/articles/AT4503827066.html




--- Brad Karp <address@hidden> wrote:

> [Re-sending, as prior post appeared not to hit the list...]
> 
> Greetings, all.
> 
> I should preface this question by confessing that I'm new to the USRP
> hardware and the gnuradio software. My students and I have only just
> started hacking on 4 USRPs with 2.4 GHz daughterboards here in
> lab. We'd like to use the platform to build a MAC protocol prototype.
> 
> As I know has been widely discussed in the gnuradio community,
> link-layer acknowledgements require fairly precise timing of
> transmissions. For example, the receiver of a data packet must delay
> a
> very short interval before sending an ACK for the packet received
> (e.g., on the order of 50 us).
> 
> My question:
> 
> What's the state of the art in precise scheduling of transmissions
> for
> gnuradio? I'm looking for building blocks I can use that will allow
> fairly precise scheduling of packet transmissions despite the 10 ms
> process scheduling granularity of Linux.
> 
> I've seen in the archives of this list that BBN's work on m-blocks
> appears at least partly motivated by precise scheduling of
> transmissions. And other list traffic suggests that m-blocks are
> being more broadly adopted; e.g., mail from Eric Blossom suggesting
> that he was enhancing the m-block code further, perhaps with the
> eventual goal of merging m-blocks into the core gnuradio
> distribution.
> 
> Is the m-block implementation in a state where my students and I
> could
> use the code to schedule packet transmissions in the MAC protocol
> we're implementing?
> 
> Are there other implementations of precise packet transmit scheduling
> anyone can point me to?
> 
> Many thanks,
> -Brad
> 
> 
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> 


Chris Albertson
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  Office: 310-336-5189  address@hidden
  KG6OMK/AG


 
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