97 lines
2.2 KiB
Mathematica
97 lines
2.2 KiB
Mathematica
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function [rxSignal,SyncErr] = rxSyncSC(rxSignal,WaveformPara,myFrameLen)
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SyncErr = 0;
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N = WaveformPara.N_FFT;
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L = WaveformPara.CP_Len;
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delay = 6000;
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c1 = WaveformPara.c1;
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c2 = WaveformPara.c2;
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preamble = WaveformPara.preamble;
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timing = estSymTiming(rxSignal,N,L);%%%%%%%%%
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tshift = delay+L+1-timing;
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if timing > WaveformPara.CP_Len+delay
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SyncErr=1;
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timing = delay+1;
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end
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rRemoveSTO = rxSignal(timing:end);%%%%%%%%%%%%%
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phi = estFFO(rRemoveSTO,N,L);%%%%%%%%%%%%
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rRemoveFFO = rRemoveSTO.*exp(-sqrt(-1)*2*pi*(1:length(rRemoveSTO))'*phi/N);
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gEst = estIFO(rRemoveFFO,N,L,c1,c2);%%%%%%%%%%%
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rRemoveIFO = rRemoveFFO.*exp(-sqrt(-1)*2*pi*(1:length(rRemoveFFO))'*(2*gEst)/N);
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fshift = phi+2*gEst;
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startWindow = length(preamble)-L+1;%%%%%%%%%%%%
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% endWindow = startWindow+WaveformPara.FrameLen-1;%
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endWindow = startWindow+myFrameLen-1;%
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rxSignal = rRemoveIFO(startWindow:endWindow);
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end
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%% APPENDIX
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function [timing,Mavg] = estSymTiming(r,N,L)
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P = zeros(length(r)-2*N/2+1,1);
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R = zeros(length(r)-2*N/2+1,1);
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M = zeros(length(P),1);
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for d = 1:length(M)
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P(d) = (r(d:d+N/2-1))'*r(d+N/2:d+N-1);
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R(d) = (r(d+N/2:d+N-1))'*r(d+N/2:d+N-1);
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M(d) = (abs(P(d)))^2/(R(d))^2;
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end
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movavgWindow = dsp.MovingAverage(L-1);
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Mavg = movavgWindow(M);
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Mavg = Mavg(L/2:end);
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[Mmax,timing] = max(Mavg);
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timing=183;
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figure
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plot(M)
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hold on;
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plot(Mavg)
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end
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function gEst = estIFO(rRemoveFFO,N,L,c1,c2)
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X = 1:2:N-1;
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v = sqrt(2)*c2(X)./c1(X);
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x1 = fft(rRemoveFFO(1:N))/sqrt(N);
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x2 = fft(rRemoveFFO(1+N+L:2*N+L))/sqrt(N);
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D = 2*(sum((abs(x2(X))).^2))^2;
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gNum = N/2;
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X1 = zeros(N,gNum);
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X2 = zeros(N,gNum);
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X1(:,1) = x1;
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X2(:,1) = x2;
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for i = 2:gNum
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X1(:,i) = [X1(3:end,i-1);X1(1:2,i-1)];
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X2(:,i) = [X2(3:end,i-1);X2(1:2,i-1)];
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end
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B = zeros(gNum,1);
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for i = 1:gNum
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B(i) = (abs(sum(...
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conj(X1(X,i)).*conj(v).*X2(X,i)...
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)))^2/D;
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end
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[Bmax,g] = max(B);
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G = [0:N/4-1,-N/4:-1];
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gEst = G(g);
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end
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function phi = estFFO(r,N,L)
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P = sum(conj(r(1:N/2)).*r(N/2+1:2*N/2));
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phi = angle(P)/pi;
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end
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