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Question about Bbb_Spd.c RRS feed

  • Question

  • Hello all,

    Now I am using SORA to fulfill the function of spectrum sensing. I have seen that in the file bbb_spd.c, there is the function of calculate the signal's energy.

    But I have some problem:

    1)Why you set the threshold to 4000? or How to decide this value?

    2)I read the code and find that the calculate result is saved in pSpdContext->BlockEnergySum[0]. But it has no units. So I want to ask that what is the 4000's units?

    3)Before calculate the energy, SORA must get a rx block, which is defined as RxStream in SoraRadio.  Whether the RxStream update automatically? Or there is some manual command to set it?

    Thanks a lot.

     
    Monday, April 11, 2011 10:57 AM

All replies

  • 1)Why you set the threshold to 4000? or How to decide this value?

    This is ad hoc. You can modify to a better value in your environment.

    2)I read the code and find that the calculate result is saved in pSpdContext->BlockEnergySum[0]. But it has no units. So I want to ask that what is the 4000's units?

    The unit is actually Watt. :c) with a complicated unknown scale, determined by Rxgain setting and the hardware configuration. If you want the absolute value, you may need to calibrate it with some instrument.

    3)Before calculate the energy, SORA must get a rx block, which is defined as RxStream in SoraRadio.  Whether the RxStream update automatically? Or there is some manual command to set it?

    Sorry. I don't understand your questions actually. You should read through the RxStream to get updated values.

    - Kun

    Monday, April 11, 2011 2:41 PM
  • Hello Kun,

    Thanks for your answer.

    The unit is Watt. And I think that the calculated result is an relative value. For example, 4000 will be a ratio, not an absolute value.

    So I want to ask that when I calculate the energy 4000 in SORA, how can I get the absolute power value? 

    Thanks a lot.

    -Albert.

    Friday, April 15, 2011 6:07 AM