wlanLLTFNoiseEstimate

Create a configuration object for a high-throughput packet. Set an initial signal-to-noise ratio of 10 dB.

cfg = wlanHTConfig;
snr = 10;

Extract the OFDM information of the L-LTF in the configuration. Change the signal-to-noise ratio to remove the noise contribution from the null subcarriers.

ofdmInfo = wlanHTOFDMInfo("L-LTF",cfg);
snrValue = snr-10*log10(ofdmInfo.FFTLength/ofdmInfo.NumTones);

Extract the field indices that correspond to the L-LTF.

indLLTF = wlanFieldIndices(cfg,"L-LTF");

Generate a time-domain waveform for the configuration.

tx = wlanWaveformGenerator([1;0;0;1],cfg);

Perform the noise estimate for 100 separate noise realizations.

noiseEst = zeros(1,100);
for i = 1:100
rx = awgn(tx,snrValue);
rxLLTF = rx(indLLTF(1):indLLTF(2));
rxSym = wlanLLTFDemodulate(rxLLTF,cfg);
noiseEst(i) = wlanLLTFNoiseEstimate(rxSym);
end

Display the average value of the noise estimate, in dB.

disp(10*log10(mean(noiseEst)))

  -10.0690