Comparing CDL channel results with NeoRadium

Using CDL-D profile, a delay spread of 10 ns, and UE velocity of 15 km/h:

% To save a new set of files, you need to set the saveFiles to true.
 
saveFiles = false;
outPath = fileparts(matlab.desktop.editor.getActiveFilename);
disp(outPath);
/Users/shahab/code/Fireball/OpenSource/onGithub/Tests/Wireless/NewProject/OnGitLab/neoradium/Playground/CompareWithMatlab/CDL/MatlabFiles
v = 15.0;                    % UE velocity in km/h
fc = 4e9;                    % carrier frequency in Hz
c = physconst('lightspeed'); % speed of light in m/s
fd = (v*1000/3600)/c*fc;     % UE max Doppler frequency in Hz
SR = 30720000;
 
cdl = nrCDLChannel;
cdl.SampleRate = SR;
cdl.DelayProfile = 'CDL-D';
cdl.DelaySpread = 10e-9;
cdl.CarrierFrequency = fc;
cdl.MaximumDopplerShift = fd;
cdl.AngleScaling = true;
cdl.MeanAngles = [130 70 80 110];
cdl.RandomStream = 'Global stream';             % Use this to be able to match the random numbers in python

Transmit antenna array is a 2 x 2 panel with 2 polarization angles. Receive antenna contains a single element antanna with 2 polarization angles. This means nt=8 and nr=2. The transmit antenna also has some orientation to exercise the code handling transformations between global and local coordinate systems.

cdl.TransmitAntennaArray.Size = [2 2 2 1 1];    % 2x2 antenna panel
cdl.TransmitAntennaArray.Element = '38.901';     % Make sure we are using 3GPP antennas. (Default is not 3GPP)
cdl.TransmitArrayOrientation = [10; 20; 30];    % Transmit antenna orientation bearing(α), downtilt(β), and slant(γ) angles in degrees
 
cdl.ReceiveAntennaArray.Size = [1 1 2 1 1];     % 1x1 antenna
cdl.ReceiveAntennaArray.Element = '38.901';     % Make sure we are using 3GPP antennas. (Default is not 3GPP)
cdl.ReceiveArrayOrientation = [180; 0; 0];     % Receive antenna orientation bearing(α), downtilt(β), and slant(γ) angles in degrees
 
curPath = fileparts(matlab.desktop.editor.getActiveFilename())
curPath = '/Users/shahab/code/Fireball/OpenSource/onGithub/Tests/Wireless/NewProject/OnGitLab/neoradium/Playground/CompareWithMatlab/CDL/MatlabFiles'

Create a random waveform.

cdlinfo = info(cdl);
T = SR * 1e-3;
Nt = cdlinfo.NumInputSignals;
 
if (saveFiles)
    txWaveform = complex(randn(T,Nt),randn(T,Nt));
    save(strcat(outPath,'/txWaveform.mat'),'txWaveform');
else
    txWaveform = load(strcat(outPath,'/txWaveform.mat')).txWaveform; % Read from file for reproducibility
end
txWaveform(201:204,3:4)
ans = 4×2 complex
  -1.4866 - 0.7976i   2.1968 - 0.0359i
   0.0656 + 0.7750i   0.4241 + 1.7407i
   0.0862 + 0.9547i   0.4668 + 1.7866i
  -0.8242 + 0.6706i   0.2277 + 1.1032i

Transmit the input waveform through the channel and get the signal received at the receiver.

rng(123);  % For Reproducibility
rxWaveform = cdl(txWaveform);
 
if (saveFiles)
    save(strcat(curPath,'/rxWaveform.mat'),'rxWaveform')
end
rxWaveform(201:204,2)
ans = 4×1 complex
   0.0125 - 0.0087i
   0.0055 + 0.0029i
  -0.0135 + 0.0006i
  -0.0056 + 0.0084i