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function rmsEVM = hePlotEVMPerSubcarrier(eqDataSym,cfgRx,evmSubcarrierPlot,varargin)
% hePlotEVMPerSubcarrier Plots EVM per subcarrier for all spatial streams
%
% RMSEVM = hePlotEVMPerSubcarrier(EQDATASYM,CFGRX,EVMSUBCARRIERPLOT)
% plots EVM per subcarriers averaged over symbols for all spatial
% streams.
%
% RMSEVM is the EVM of EQDATASYM in decibels.
%
% EQDATASYM are the demodulated HE-Data field OFDM symbols for a user,
% specified as a Nsd-by-Nsym-by-Nss matrix of real or complex values,
% where Nsd is the number of data subcarriers in the HE-Data field and
% Nsym is the number of OFDM symbols, and Nss is the number of spatial
% streams.
%
% CFGRX is the format configuration object of type <a href="matlab:help('wlanHERecoveryConfig')">wlanHERecoveryConfig</a>,
% <a href="matlab:help('wlanHESUConfig')">wlanHESUConfig</a>, or <a href="matlab:help('wlanHETBConfig')">wlanHETBConfig</a>.
%
% EVMSUBCARRIERPLOT is a system object of type <a href="matlab:help('dsp.ArrayPlot')">dsp.ArrayPlot</a>.
%
% RMSEVM = hePlotEVMPerSubcarrier(...,USERIDX,NUMUSERS) displays user
% number and number of user information in the figure title.
% Copyright 2019-2020 The MathWorks, Inc.
[Nsd,~,Nss] = size(eqDataSym);
rmsEVMPerSC = zeros(Nsd,Nss);
if nargin == 5
userIdx = varargin{1};
numUsers = varargin{2};
elseif nargin == 4
userIdx = varargin{1};
numUsers = 1; % Number of users are unknown, prefix this to 1
end
EVM = comm.EVM;
EVM.ReferenceSignalSource = 'Estimated from reference constellation';
EVM.ReferenceConstellation = wlanReferenceSymbols(cfgRx);
for iss = 1:Nss
for isd = 1:Nsd
rmsEVMPerSC(isd,iss) = EVM(eqDataSym(isd,:,iss).');
release(EVM);
end
end
if isa(cfgRx,'wlanHERecoveryConfig')
ofdmInfo = wlanHEOFDMInfo('HE-Data',cfgRx.ChannelBandwidth,cfgRx.GuardInterval,[cfgRx.RUSize cfgRx.RUIndex]);
else
ofdmInfo = wlanHEOFDMInfo('HE-Data',cfgRx);
end
dataInd = ofdmInfo.ActiveFFTIndices(ofdmInfo.DataIndices);
Nfft = ofdmInfo.FFTLength;
evmFFT = nan(Nfft,Nss);
rmsEVM = 20*log10(rmsEVMPerSC/100);
evmFFT(dataInd,:) = rmsEVM;
evmSubcarrierPlot.XOffset = -Nfft/2;
str = cell(Nss,1);
for iss=1:Nss
str{iss} = sprintf('Spatial stream %d',iss);
end
evmSubcarrierPlot.ChannelNames = str;
if nargin>3
evmSubcarrierPlot.Name = sprintf('EVM per subcarrier, user#%d/%d',userIdx,numUsers);
else
evmSubcarrierPlot.Name = sprintf('EVM per subcarrier');
end
evmSubcarrierPlot(evmFFT)
evmSubcarrierPlot.show
release(evmSubcarrierPlot);
end