Converting 4 QAM to 16 QAM - 16 QAM produces error when generating signal
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clear all close all clc T=10000; dB=40; % SNR value(dB)
N=12; Lh=5; M=2; % fractional (Ts/M)
h=randn(M,Lh+1)+sqrt(-1)*randn(M,Lh+1); for i=1:M, h(i,:)=h(i,:)/norm(h(i,:)); end
s=round(rand(1,T))*2-1; % QPSK or 4 QAM symbol sequence
s=s+sqrt(-1)*(round(rand(1,T))*2-1);
% Produce a noisy signal x=zeros(M,T); SNR=zeros(1,M); for i=1:M x(i,:)=filter(h(i,:),1,s); vn=randn(1,T)+sqrt(-1)*randn(1,T); vn=vn/norm(vn)*10^(-dB/20)*norm(x(i,:)); SNR(i)=20*log10(norm(x(i,:))/norm(vn)); x(i,:)=x(i,:)+vn; end SNR=SNR;
Lp=T-N; X=zeros((N+1)*M,Lp); for i=1:Lp for j=1:M X((j-1)*(N+1)+1:j*(N+1),i)=x(j, i+N:-1:i).'; end end
e=zeros(1,Lp); f=zeros((N+1)*M,1); f(N*M/2)=1; R2=2.0; mu=0.0012; for i=1:Lp e(i)=abs(f'*X(:,i))^2-R2; % Momentary error f=f-mu*2*e(i)*X(:,i)*X(:,i)'*f; % Equalizer update equation end
sb=f'*X;
figure
plot(s,'s');
grid,title('Gonderilen semboller'); xlabel('Reel'),ylabel('Sanal')
axis([-2 2 -2 2])
figure
plot(x,'o'); % kanal ve gürültü ile bozulmuþ alýnan sembollerin çizimi
grid, title('Alinan ornekler'); xlabel('Reel'), ylabel('Sanal')
figure
plot(sb,'o'); % denkleþtirilen sembollerin çizimi
grid, title('Denklestirilen Semboller'), xlabel('Reel'), ylabel('Sanal')
figure
plot(abs(e)/100); % show the convergence
%semilogy(abs(e)/100,'b-p');
grid, title('Kor Ogrenme Egrisi'), xlabel('Ogrenme Adimi'), ylabel('MSE')
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