function [p,Pd,Pmmse]=ss_pemmse(snrindb,R,PN1,PN2,PN3,PN4)
%本函數(shù)在一定的信噪比條件下測(cè)試出相應(yīng)的誤碼率，
%針對(duì)單用戶和傳統(tǒng)多用戶以及解相關(guān)器多用戶
%考慮到遠(yuǎn)近效應(yīng)的影響
%[p1,p,Pd,Pmmse]分別返回單用戶，傳統(tǒng)多用戶檢測(cè)
%解相關(guān)檢測(cè)，mmse檢測(cè)的誤碼率
Lc=31;
M=7;%干擾的幅度
w0=1;
%
%由給出的信噪比計(jì)算出實(shí)際的信噪比
snr=10^(snrindb/10);
%噪聲方差假設(shè)為1，信號(hào)的幅度也設(shè)為1
sgma=4;
%比特能量,定義噪聲功率=2*sgma^2
Eb=2*sgma^2*snr;
N01=2*sgma;
%碼片能量
E_chip=Eb/Lc;
%
S=inv(R);
%
N=10000;

numoferr=0;
numoferrofde=0;
numoferrmmse=0;
%
%
%產(chǎn)生10000個(gè)數(shù)據(jù)比特
for i=1:N,
    %
    %產(chǎn)生第一個(gè)用戶數(shù)據(jù)
    temp=rand;
    if (temp<0.5),
        data1=-1;
    else
        data1=1;
    end;
    %重復(fù)產(chǎn)生的比特
    for j=1:Lc,
        repeated_data1(j)=data1;
    end;
    %
    %產(chǎn)生第二個(gè)用戶數(shù)據(jù)
    temp=rand;
    if (temp<0.5),
        data2=-1;
    else
        data2=1;
    end;
    %重復(fù)產(chǎn)生的比特
    for j=1:Lc,
        repeated_data2(j)=data2;
    end;
    %
    %產(chǎn)生第三個(gè)用戶數(shù)據(jù)
    temp=rand;
    if (temp<0.5),
        data3=-1;
    else
        data3=1;
    end;
    %重復(fù)產(chǎn)生的比特
    for j=1:Lc,
        repeated_data3(j)=data3;
    end;
     %
    %產(chǎn)生第四個(gè)用戶數(shù)據(jù)
    temp=rand;
    if (temp<0.5),
        data4=-1;
    else
        data4=1;
    end;
    %重復(fù)產(chǎn)生的比特
    for j=1:Lc,
        repeated_data4(j)=data4;
    end;
    %
    %信號(hào)的幅度
    A1=0.5;
    A2=0.5;
    A3=0.5;
    A4=0.5;
    %
    %the matrix of the amplitude of signal
    A=[A1 0 0 0;0 A2 0 0;0 0 A3 0;0 0 0 A4];
    %發(fā)送信號(hào)為
    tran_seq1=A1*sqrt(E_chip)*repeated_data1.*PN1;
    tran_seq2=A2*sqrt(E_chip)*repeated_data2.*PN2;
    tran_seq3=A3*sqrt(E_chip)*repeated_data3.*PN3;
    tran_seq4=A4*sqrt(E_chip)*repeated_data3.*PN4;
    trans_sig=tran_seq1+tran_seq2+tran_seq3+tran_seq4;
     %
    %方差為sgma^2的gauss white noise
    noise=sgma*rand(1,Lc);
    %
    %干擾
    n=(i-1)*Lc+1:i*Lc;
    interference=0;%0.25*M*sin(w0*n);
    %
    N02=(0.25*M)^2/2;
    N0=(N01)/2;
    % %matrix of mmse
    %
    %the matrix of the amplitude of signal
    
    %
    A=[A1 0 0 0;0 A2 0 0;0 0 A3 0;0 0 0 A4];
    Lmmse=inv(R+sgma*inv(A)*inv(A));
    %the receive signal of the first user
    %
    nr=A1*(noise+interference);
    %
    %
    %接收信號(hào)
    
    rec_sig=trans_sig+nr;
   
    %the matrix of receive signal
    Y1= sum(rec_sig.*PN1)/Lc;
    Y2= sum(rec_sig.*PN2)/Lc;
    Y3= sum(rec_sig.*PN3)/Lc;
    Y4= sum(rec_sig.*PN4)/Lc;
    Y=[Y1 Y2 Y3 Y4]';
    %
   
    dataout1=[1 0 0 0]*(S*Y);
    datammse=[1 0 0 0]*(Lmmse*Y);
    %
    %
    %從接收信號(hào)中產(chǎn)生判決變量
    
    %multiusers
    temp=rec_sig.*PN1;
    decision_variable=sum(temp)/Lc;
    %multiusers of decorrelating detector
    dataout=dataout1;
    %
    %進(jìn)行判決
    
    %
    %multiusers detection
    if (decision_variable<0),
        decision=-1;
    else
        decision=1;
    end;
    %%multiusers of decorrelating detection
    if (dataout<0),
        decisionofde=-1;
    else
        decisionofde=1;
    end;
    %detection of mmse detector
    if (datammse<0),
        decisionmmse=-1;
    else
        decisionmmse=1;
    end;
    %I如果存在傳輸中的錯(cuò)誤，計(jì)算器累加操作
     
    %
    if (decision~=data1),
        numoferr=numoferr+1;
    end;
    %
    if (decisionofde~=data1),
        numoferrofde=numoferrofde+1;
    end;
    % 
    if (decisionmmse~=data1),
       numoferrmmse=numoferrmmse+1;
    end;
    %
end;
p=numoferr/N;
Pd=numoferrofde/N;
Pmmse=numoferrmmse/N;