1 files changed, 131 insertions, 0 deletions
diff --git a/emu-radio/lte-emulator/fading-traces/fading_trace_generator.m b/emu-radio/lte-emulator/fading-traces/fading_trace_generator.m
new file mode 100644
index 00000000..abae5b28
--- /dev/null
+++ b/emu-radio/lte-emulator/fading-traces/fading_trace_generator.m
@@ -0,0 +1,131 @@
+clear all;
+close all;
+
+c = 3e8; 
+% Excess taps delay (according to 3GPP TS 36.104 Annex B.2)
+delays_pedestrianEPA = [0 30e-9 70e-9 90e-9 120e-9 190e-9 410e-9];
+delays_vehicularEVA = [0 30e-9 150e-9 310e-9 370e-9 710e-9 1090e-9 1730e-9 2510e-9];
+delays_urbanETU = [0 50e-9 120e-9 200e-9 230e-9 500e-9 1600e-9 2300e-9 5000e-9];
+Td = 100/c;
+
+% Realtive power of taps (according to 3GPP TS 36.104 Annex B.2)
+power_pedestrianEPA = [0.0 -1.0 -2.0 -3.0 -8.0 -17.2 -20.8];
+power_vehicularEVA = [0.0 -1.5 -1.4 -3.6 -0.6 -9.1 -7.0 -12.0 -16.9];
+power_urbanETU = [-1.0 -1.0 -1.0 0.0 0.0 0.0 -3.0 -5.0 -7.0];
+
+
+% DL EARFCN=500
+% fc = 2160e6; %
+
+% UL  EARFCN=18100
+fc = 1930e6;
+
+lambda = c/fc;
+v_km_h = 3.0;  % speed of mobile node
+v_m_s = v_km_h / 3.6;
+fd = v_m_s / lambda; % doppler shift
+
+
+
+
+% when working with an FFT, the normalized frequency w is
+% w = 2 * pi * (f/fs) * t
+% hence the max normalized frequency w=2*pi corresponds to f = fs,
+% hence fs is also the max frequecy of our PowerSpectralDensity
+fs = 20e6; 
+
+% sampling period must be determined corresponding to the sampling
+% frequency, because of the properties of an FFT
+% in other words, if ts = 1/fs, then the samples of the FFT will be
+% spaced by fs (which is what we want)
+ts = 1/fs; % sampling period (i.e., 1 subframe duration)
+
+
+% create the channel object
+c = rayleighchan(ts, fd, delays_pedestrianEPA, power_pedestrianEPA);
+%c = rayleighchan(ts, fd, delays_vehicularEVA, power_vehicularEVA);
+%c = rayleighchan(ts, fd, delays_urbanETU, power_urbanETU);
+%c.StorePathGains = 1;
+c.ResetBeforeFiltering = 0;
+c.NormalizePathGains = 1;
+
+TTI = 0.001;
+
+% number of samples of one channel realization
+numSamples = TTI / ts;
+
+% total trace duration in s
+traceDuration = 10.0;
+
+numRBs = 100;
+
+sig = zeros(numSamples, 1); % Signal
+sig(1) = 1; % dirac impulse
+
+[psdsig,F] = pwelch(sig,[],[],numRBs,fs,'twosided');     
+
+for ii=1:round((traceDuration/TTI))
+        
+    % y is the frequency response of the channel
+    y = filter(c,sig);   
+    
+%     [Pxx,F] = PWELCH(X,WINDOW,NOVERLAP,NFFT,Fs) returns a PSD computed as
+%     a function of physical frequency (Hz).  Fs is the sampling frequency
+%     specified in Hz.  If Fs is empty, it defaults to 1 Hz.
+%  
+%     F is the vector of frequencies at which the PSD is estimated and has
+%     units of Hz.  For real signals, F spans the interval [0,Fs/2] when NFFT
+%     is even and [0,Fs/2) when NFFT is odd.  For complex signals, F always
+%     spans the interval [0,Fs).
+
+
+    [psdy,F] = pwelch(y,[],[],numRBs,fs);      
+    
+    %% the gain in frequency is obtained by dividing the psd of the received signal
+    %% by the psd of the original signal. Note that the psd of the original
+    %% signal is constant in frequency (since the transform of a delta is a
+    %% constant)
+    ppssdd(:,ii) = psdy ./ psdsig;  
+    
+
+    % this to plot
+    %   figure;
+    %    PWELCH(y,[],[],numRBs,fs);
+
+    % alternative plot
+    %figure;
+    %plot(F, 10.*log10(ppssdd(:,ii)));
+end
+
+surf(10.*log10(ppssdd));
+title ('Fading Pedestrian EPA 3kmph');
+%title ('Fading Vehicular EVA 60kmph');
+%title('Fading Urban ETU 0 kmph');
+%title('Fading Urban ETU 3 kmph');
+%title('Fading Urban ETU 30 kmph');
+tag = 'EPA_3kmph';
+%tag = 'EVA_60kmph';
+%tag = 'ETU_0kmph';
+%tag = 'ETU_3kmph';
+%tag = 'ETU_30kmph';
+ylabel ('RB index');
+xlabel ('time [ms]');
+zlabel ('Amplitude [dB]');
+
+%FILE GENERATION
+TAG = upper(tag);
+len = round((traceDuration/TTI));
+
+file = fopen(strcat('fading_trace_',tag,'.fad'),'at');   
+
+        
+for j=1:numRBs
+    for s=1:len
+        fprintf(file, '%g ',10.*log10(ppssdd(j, s)));
+
+    end
+    fprintf(file, '\n');
+end
+
+fclose(file);
+