Re: [Discuss-gnuradio] MAC layer development and USRP2

[Charles Irick]

Thanks for the reply George. I'm still looking for a little more
information on this topic.

- What is PMT
- Why was m-block removed
- Has anyone measured latency with the USRP2 and GigE
- Is GigE alone not capable of handling MAC turnaround times or is
software to blame for this
- Is the scheduler the main issue in the way it handles i/o between blocks

Charles

On Sun, Mar 14, 2010 at 5:52 PM, George Nychis <address@hidden> wrote:
> Think of it this way...
>
> MAC *development* is severely limited by GNU Radio... it lacks the
> much-needed functionality to make information passing between the
> blocks rich, simple, and bi-directional.  Some of the  building blocks
> are in place (e.g., PMT), and the m-block was implemented to solve the
> rest of the problems, but was deprecated (maybe removed as of now?).
>
> MAC *performance* is limited by several things: 1) delay between GNU
> Radio and the USRP/USRP2, 2) signal processing delay (GNU Radio), and
> (3) jitter (e.g., unpredictable delay) ... (1) is reduced a little by
> USRP2 using GigE, but it's still not down to traditional MAC
> turnaround times (10s of us).  (2) benefits from Moore's law.  (3)
> kind of depends on whether you use realtime scheduling and how your
> data hits delays in queues mainly.
>
> All in all... still an open problem IMO.
>
> - George
>
>
> On Sun, Mar 14, 2010 at 5:06 PM, Charles Irick <address@hidden> wrote:
>> I've been reading some papers related to MAC layer development on the
>> USRP, but they seem to have tapered off with the USRP2. Does anyone
>> have any information about MAC layer and protocol development for the
>> USRP2. Has this been satisfied with things like timestamps and gigE?
>> Any current papers or web links related to USRP2 protocol level
>> development? Thanks.
>>
>> Charles
>>
>>
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>