% adaptiveMMSE(LMS)多用戶檢測（非盲），同步信號
clc
clear
fbconnection=[0 1 0 0 1]; % fbconnection為m序列的一個本原多項式
mseq=m_sequence(fbconnection); % 產生m序列
fbconnection1=[0 0 1 0 1];
fbconnection2=[0 1 1 1 1]; % fbconnection1,fbconnenction2為m序列的一對優先對
goldseq=gold_seq(fbconnection1,fbconnection2); % 產生gold序列
N=2^length(fbconnection)-1; % N為gold序列長度，即為擴頻倍數（擴頻增益）
ind1=find(mseq==0);
mseq(ind1)=-1; % 極性變換
ind2=find(goldseq==0);
goldseq(ind2)=-1;% 極性變換
% goldseq=1/sqrt(31)*goldseq;

bit_number=2000; % bit_number為用戶數據長度
K=6; % K為DS-CDMA信號中用戶個數

ABer=zeros(1,13);
ReN=500;
figure
for rei=1:ReN;
    
    data=zeros(K,bit_number);
    for i=1:K
        data(i,:)=randsrc(1,bit_number);
    end % 產生K*bit_number的用戶混合矩陣
    u=1*1e-1;
   
    
         SNR=-2:10;
         n1=length(SNR);
         Ber=zeros(1,length(SNR));
         j=1;
         a=SNR(1);
         b=SNR(n1);

         power1=0;% 假設第一個用戶為期望用戶，發射功率為0dB，其他用戶為干擾用戶，干擾功率為InterpowerdB,
         Interpower=[4 4 4 4 4];
        % Interpower=rand(1,K-1)*10;
        % Interpower=floor(Interpower)+1;
         Power=[power1,Interpower];
         A=zeros(1,K);
        for k=1:K
             A(k)=sqrt(10^(Power(k)/10));
        end
    
        s1=goldseq(1,:)';
         for snr=a:b
             r=zeros(N,bit_number);
            for k=1:K  
                 r1=zeros(N,bit_number);
r1=goldseq(k,:)'*data(k,:);
                 r1=awgn(r1,snr);
                r=r+A(k)*r1;
            end	
    
            e=zeros(1,bit_number);
            y1=zeros(1,bit_number);
            x=zeros(N,1);
            for i=1:100
                 y1(i)=sign(x'*r(:,i)); 
                 e(i)=data(1,i)-y1(i);;
                x=x+u*e(i)*r(:,i);
            end

            for i=101:bit_number
                y1(i)=sign(x'*r(:,i));
                e(i)=data(1,i)-y1(i);
            end
            [number,ber]=symerr(y1,data(1,:));
            Ber(j)=ber;
             j=j+1;
    
         end
         ABer=Ber+ABer;
   
        SNR=a:b;
        semilogy(SNR,Ber,':*');
        hold on;
        u=u*10;
    end
Ber=ABer/ReN;
semilogy(SNR,Ber,'r-^');
title('同步DS-CDMA信號的線性MMSE(LMS算法)多用戶檢測');
xlabel('SNR(dB)');
ylabel('BER');
grid on