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Question about Signal Correlation Detection for 11a RRS feed

  • Question

  • In the function "BB11ARxCarrierSense" of arx_cs.c

     if (iCorrelation > (iEnergy - (iEnergy >> 3)) && (iCorrelation > (signed)(pRxContextA->uiCSCorrThreshold)))
           {
                pRxContextA->__uHighEnergyCounter++;
                if (pRxContextA->__uHighEnergyCounter >= 3)
                {                
                    hr = BB11A_OK_POWER_DETECTED;
                    break;
                }
            }

    my questions as follows:

    1. what means "iCorrelation > (iEnergy - (iEnergy >> 3)"?

    2. why is it a judge condition for BB11A_OK_POWER_DETECTED?

    3. if I change it to "iCorrelation > (iEnergy - (iEnergy >> 2 or 4 or others)", can CarrierSense works correctly?

    Tuesday, September 25, 2012 8:02 AM

Answers

  • How to realize carrier sense is implementation dependent, not specified in 802.11 standard. Here we provide an sample implementation which works well in our experiments, but not necessary to be the optimal. You can modify it if you want and maybe you can get a better one. (If you get a better one in your experiment, please share it in the forum so that all the Sora users can benefit from it.)

    -Jiansong

    Thursday, October 11, 2012 4:12 AM