clc
clear 
k=16;                              %用戶數為k
numbits=10000;                    %比特序列數
exno=2:1:20;                     %Eb/N0
BER=zeros(k,length(exno));        %PIC k個用戶的誤碼率
ber=zeros(k,length(exno));        %NOPIC k個用戶的誤碼率
BER1=zeros(1,length(exno));       %PIC的誤碼率
BER2=zeros(1,length(exno));       %NOPIC的誤碼率
bits_add=bitgene(k);              %產生擴頻碼

S=zeros(1,numbits*31/2);          %經過QPSK調制的信號
SS=zeros(k,numbits*31/2);         %QPSK調制與擴頻后的信號
S_out=zeros(k,numbits);
bits=zeros(k,numbits);            %產生的隨機信號
bits_double=zeros(k,numbits);     %對產生的隨機信號double
%%%%%%%%%%%%%%%%%%%%%%%%%%%%產生信號%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
for i=1:k
    bits(i,:)=Sbits(numbits);
    bits_double(i,:)=double(bits(i,:));
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%QPSK調制&&擴頻%%%%%%%%%%%%%%%%%%%%%%%%%%%
for x=1:k
    S_qpsk(x,:)=QPSK_mod(bits_double(x,:));
    SS(x,:)=cdma(S_qpsk(x,:),bits_add(x,:));
    S(1,:)=SS(x,:)+S(1,:);
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%加入噪聲%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
SNR=exno-10*log10(31/2);
output=Gnoise(S(1,:),SNR);
%%%%%%%%%%%%%%%%%%%%%%%%%%%PICMUD與解擴%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
for y=1:length(exno)
    [bits_out,S_out,r]=picmud(output(y,:),bits_add,k);   %bis_out為PIC的信號 S_out為NOPIC的信號,均為k行信號
    for z=1:k
        bits_qpskout(z,:)=DEQPSK(bits_out(z,:));
        S_qpskout(z,:)=DEQPSK(S_out(z,:));
        BER(z,y)=Error(bits_qpskout(z,:),bits_double(z,:));
        ber(z,y)=Error(S_qpskout(z,:),bits_double(z,:));
    end
end


                           
semilogy(exno,BER(1,:),'^k-');

hold on
semilogy(exno,ber(1,:),'+r-');
xlabel('Eb/No');
ylabel('BER');
title('單用戶匹配濾波與并行干擾刪除多用戶檢測誤碼率比較');
legend('一級PICMUD','匹配濾波');
grid on