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Questions about demod11 RRS feed

  • Question

  •  Hi, everyone! I'm trying to use demod11 for offline test and the protocol I use is protocol 802.11a. But I have some questions.

     First, as I comprehend, TestMod11A reads one frame from input file, implenments OFDM modulation and then writes the modulated symbols to output file (***.tx). ConvertModFile2DumpFile converts tx file to rx signal file (***.dmp). If this rx signal file is obtained, I can call CsFrameDemod to demodulate the original data. Here, I have a question. If I reads several frames from input file, OFDM-modulate them and writes to output file, and then I convert the file to rx signal file, can I simply call CsFrameDemod to demodulated all these frames? I wonder after PrepareSigStream is called,  BB11ARxFrameDemod will separate these frames or not.

     Second, I have no idea what the segment codes below performs.

            // Possible the scan pointer wraps to the buffer header
            dReq = buffer_span(pbSPTemp, SoraRadioGetRxStreamPos(&RxStream), SoraRadioGetRxStreamSize(&RxStream)) * 28.0 / 40;
            dCost = TimerRead(&ti) * 1000;
            dRatio = dCost / dReq;

            printf("[noise]  req: %9.3fus  cost: %9.3fus \n", dReq, dCost);
            iNoiseCounter++;
            dNoiseAverage += dRatio;
            dNosieSD += dRatio * dRatio;
            dNoiseMax = (dNoiseMax >= dRatio)?dNoiseMax : dRatio;
            if (dRatio >= 0.8)
            {
                dNoiseAbove0_8Counter++;
                if (dRatio >= 1.0)
                {
                    dNoiseAboveCounter++;
                }
            }

     Waiting for your answer. Thanks.

    Saturday, June 30, 2012 3:34 AM

Answers

  • Hi ychm,
    Your understanding of TestMod11A, ConvertModFile2DumpFile and CsFrameDemod are generally correct. Currently demod11 tool does not support modulate multiple frames, so you can refine its implementation to achieve your goal. The conversion part and demodulation part are expected to support multiple frames in one file.

    About the code snippet, it is doing some statistics about noise period in the demodulation process. 'dReq' is the time occupied by a period of noise samples. 'dCost' is the time used to process them.
    Tuesday, July 10, 2012 2:55 AM
    Answerer

All replies

  • Hi ychm,
    Your understanding of TestMod11A, ConvertModFile2DumpFile and CsFrameDemod are generally correct. Currently demod11 tool does not support modulate multiple frames, so you can refine its implementation to achieve your goal. The conversion part and demodulation part are expected to support multiple frames in one file.

    About the code snippet, it is doing some statistics about noise period in the demodulation process. 'dReq' is the time occupied by a period of noise samples. 'dCost' is the time used to process them.
    Tuesday, July 10, 2012 2:55 AM
    Answerer
  • Thanks.
    Wednesday, July 11, 2012 1:36 AM