mirror of https://github.com/PentHertz/srsLTE.git
44 lines
980 B
Matlab
44 lines
980 B
Matlab
function [ fs eps p_m w2] = find_pss( x, N_id_2, doplot, threshold)
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if nargin == 2
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doplot = false;
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threshold = 0;
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end
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if nargin == 3
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threshold = 0;
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end
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c=lte_pss_zc(N_id_2);
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cc=[zeros(33,1); c; zeros(33,1)];
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ccf=[0; cc(65:128); cc(2:64)];
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ccf=conj(ifft(ccf));
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w2=conv(x,ccf);
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if (doplot)
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%plot(10*log10(abs(w2)));%./mean(abs(w2))));
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plot(abs(w2))
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%axis([0 length(w2) 0 20])
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end
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[m i]=max(abs(w2));
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fs=i-960;
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p_m = m/mean(abs(w2));
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if doplot
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fprintf('Frame starts at %d, m=%g, p=%g, p/m=%g dB\n',fs, ...
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mean(abs(w2)), m, 10*log10(m/mean(abs(w2))));
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end
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% Estimate PSS-aided CFO
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if (i > 128 && i<length(x)&& p_m > threshold)
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y=ccf.*x(i-128:i-1);
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y0=y(1:64);
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y1=y(65:length(y));
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eps=angle(conj(sum(y0))*sum(y1))/pi;
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else
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eps = NaN;
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fs = NaN;
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end
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end
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