Re: [Discuss-gnuradio] The low performance of gr-ieee-802.11 running on b210 ????

Hi all.

I was reading about your implementation Siyu and i am trying to do the same (ieee802.11 over USRP B210 - intel i7) but i haven't been able to. Could you indicate me what you did. It would help me a lot.

I had overruns and i solved it by changing the transport parameters. I have the transceiver in only one pc. I run it and I try to do a ping but the ping just is received for the transceiver. It is not answered, then i don't achieved comunication.

If you could share me your .grc file would be great too, if you maybe modified some important parameteres or something in the flowgraph.

Thanks a lot.

Best regards,

Cristian

2017-05-09 16:37 GMT-05:00 Marcus Müller <marcus.mueller@ettus.com>:

Hi Siyu,

well, transceiver performance depends effectively on bit error rate of the underlying transport – and that error rate might be limited by noise, by interference, or by effects like clipping and saturation, overly large clock offset and much more. I'd say: add a time and a frequency sink to your receiver flow graph, and watch the statistics! Analyze what might be going wrong. In a first approach: Play with the TX and RX gains, carefully.

To be completely honest, how well that transceiver works is something no-one outside your lab can assess – you'll have to start diagnosing things yourself :)

Best regards,

Marcus

On 09.05.2017 22:11, zhan siyu wrote:

Hi all,

Recently, I bought two b210 usrps. And I just successfully setup the usrps to run the gr-ieee802.11, written by Bastian. I used 2 desktops connected to usrp and run the transceiver.py program. I can ping from one to the other. I 'm so excited as I finally made it. However, I used the iperf to test the throughput between two computers through the 802.11p. The result is too low, only around 120kb/s , as shown by the log of iperf server side. No overrun or underrun errors. The sample rate is 10M. The OS of my computers is ubuntu 16 and cpu is i7. Also, the %cpu is only 310% as shown by the top command. The distance between two usrps is about 0.5 meters.  Is the performance too low ? I think it should be much higher. But how can I improve it ? Where is the bottleneck ? 

Can anyone help me ? Thanks ahead.

Best Regards.

Siyu

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