mirror of https://github.com/pvnis/srsRAN_4G.git
You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
44 lines
980 B
Matlab
44 lines
980 B
Matlab
function [ fs eps p_m w2] = find_pss( x, N_id_2, doplot, threshold)
|
|
if nargin == 2
|
|
doplot = false;
|
|
threshold = 0;
|
|
end
|
|
if nargin == 3
|
|
threshold = 0;
|
|
end
|
|
|
|
c=lte_pss_zc(N_id_2);
|
|
cc=[zeros(33,1); c; zeros(33,1)];
|
|
ccf=[0; cc(65:128); cc(2:64)];
|
|
ccf=conj(ifft(ccf));
|
|
|
|
w2=conv(x,ccf);
|
|
if (doplot)
|
|
%plot(10*log10(abs(w2)));%./mean(abs(w2))));
|
|
plot(abs(w2))
|
|
%axis([0 length(w2) 0 20])
|
|
end
|
|
[m i]=max(abs(w2));
|
|
fs=i-960;
|
|
p_m = m/mean(abs(w2));
|
|
|
|
if doplot
|
|
fprintf('Frame starts at %d, m=%g, p=%g, p/m=%g dB\n',fs, ...
|
|
mean(abs(w2)), m, 10*log10(m/mean(abs(w2))));
|
|
end
|
|
|
|
% Estimate PSS-aided CFO
|
|
if (i > 128 && i<length(x)&& p_m > threshold)
|
|
y=ccf.*x(i-128:i-1);
|
|
|
|
y0=y(1:64);
|
|
y1=y(65:length(y));
|
|
|
|
eps=angle(conj(sum(y0))*sum(y1))/pi;
|
|
else
|
|
eps = NaN;
|
|
fs = NaN;
|
|
end
|
|
end
|
|
|