www.gusucode.com > wlan 源码程序 matlab案例代码 > wlan/EstimateSISOChannelUsingLLTFandSmoothingFilterExample.m

    %% Estimate SISO Channel Using L-LTF and Smoothing Filter

%%
% Create a VHT format configuration object. Generate a time-domain waveform
% for an 802.11ac VHT packet.
vht = wlanVHTConfig;
txWaveform = wlanWaveformGenerator([1;0;0;1],vht);
%%
% Multiply the transmitted VHT signal by 0.2 - 0.6i and pass it through an
% AWGN channel having a 10 dB SNR.
rxWaveform = awgn(txWaveform*complex(0.2,-0.6),10);
%%
% Extract the L-LTF from the received waveform. Demodulate the L-LTF.
idxLLTF = wlanFieldIndices(vht, 'L-LTF');
lltfDemodSig = wlanLLTFDemodulate(rxWaveform(idxLLTF(1):idxLLTF(2),:),vht);
%%
% Use the demodulated L-LTF signal to generate the channel estimate.
est = wlanLLTFChannelEstimate(lltfDemodSig,vht);
%%
% Plot the channel estimate.
scatterplot(est)
grid
%%
% The channel estimate is noisy, which may lead to inaccurate data
% recovery.
%%
% Estimate the channel again with the filter span set to 11.
est = wlanLLTFChannelEstimate(lltfDemodSig,vht,11);
scatterplot(est)
grid
%%
% The filtering provides a better channel estimate.