[USRP-users] Measurement of throughput and delay during USRP transmission

Marcus Müller marcus.mueller at ettus.com
Wed Apr 22 06:37:30 EDT 2015


Dear Jaehoon,

the troughput doesn't need measuring -- it's simply the sampling rate
you set!
If your system can't keep up with that sampling rate, you will see "O"
and/or "U" errors.

Delay is a bit of a more complicated thing to measure, but what about this:

You make a loopback from TX to RX (include attenuator!);

you use a flow graph that simply looks like this

file_source(precomputed noise file, a few seconds long; repeat=false)
--> usrp_sink
usrp_source --> file_sink(measurement)

then you open the generated Python file and add (assuming your sink has
the name usrp_sink0, and your source usrp_source0; this might be
different for you!):

usrp_source0.set_time_now(uhd.time_spec(0))
timestamp = uhd.time_spec(2.0)
usrp_source0.set_start_time(timestamp)
usrp_sink0.set_start_time(timestamp)

before the line that contains tb.start().

Afterwards, you just correlate your measurement with your precomputed
noise file; the maximum correlation will mark your delay.

Notice that this value will depend on various factors -- sampling rate,
frequency, bandwidth... and you will need to measure this for all
configurations you want to have calibrated.

Best regards,
Marcus

On 04/22/2015 12:27 PM, 이재훈 via USRP-users wrote:
>
> Dear list
>
>  
>
>  
>
> Hi, I need to measure the throughput and transmission delay between Tx
> and Rx USRP.
>
>  
>
> How can I measure that values?  
>
>  
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> I want to other GRC references codes concerning throughput and delay.
>
>  
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> Thanks
>
>  
>
> Jaehoon
>
>  
>
>
>
> _______________________________________________
> USRP-users mailing list
> USRP-users at lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

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