How do I modify this code in order to estimate the channel without using the pilot location?

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Hanojhan Rajahrajasingh 2022-10-24

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https://ww2.mathworks.cn/matlabcentral/answers/1833558-how-do-i-modify-this-code-in-order-to-estimate-the-channel-without-using-the-pilot-location

编辑： Hanojhan Rajahrajasingh 2022-10-24

function [H_MMSE] = MMSEesti(Y,Xp,pilot_loc,Nfft,Nps,h,SNR)
% MMSE channel estimation function
% Inputs:
% Y = Frequency-domain received signal
% Xp = Pilot signal
% pilot_loc = Pilot location
% Nfft = FFT size
% Nps = Pilot spacing
% h = Channel impulse response
% SNR = Signal-to-Noise Ratio[dB]
% output:
% H_MMSE = MMSE channel estimate
snr = 10.^(SNR*0.1); Np=Nfft/Nps; k=1:Np;
H_tilde = Y(1,pilot_loc(k))./Xp(k); % LS estimate Eq.(6.12) or (6.8)
k=0:length(h)-1; %k_ts = k*ts;
hh = h*h'; tmp = h.*conj(h).*k; %tmp = h.*conj(h).*k_ts;
r = sum(tmp)/hh; r2 = tmp*k.'/hh; %r2 = tmp*k_ts.’/hh;
tau_rms = sqrt(r2-r^2); % rms delay
df = 1/Nfft; %1/(ts*Nfft);
j2pi_tau_df = 1i*2*pi*tau_rms*df;
K1 = repmat([0:Nfft-1].',1,Np); K2 = repmat([0:Np-1],Nfft,1);
rf = 1./(1+j2pi_tau_df*Nps*(K1-K2)); % Eq.(6.17a)
K3 = repmat([0:Np-1].',1,Np); K4 = repmat([0:Np-1],Np,1);
rf2 = 1./(1+j2pi_tau_df*Nps*(K3-K4)); % Eq.(6.17a)
Rhp = rf;
Rpp = rf2 + eye(length(H_tilde),length(H_tilde))/snr; % Eq.(6.14)
H_MMSE = transpose(Rhp*inv(Rpp)*H_tilde.'); % MMSE estimate Eq.(6.15)
end