www.pudn.com > clipping_ccdf.rar > clipping_ccdf.m

%clipping technique 
%papr of the ofdm signals 
clear all; 
close all; 
 c1=128; 
 n1=200;  
 Fs=100; 
 MM=1:.1:10;    %CCDF的门限值 
 ccdf1=zeros(1,91); 
 ccdf2=zeros(1,91); 
 for i=1:n1; 
 x(:,1)=randsrc(c1,1,[+1 -1 +3 -3]); 
 x(:,2)=randsrc(c1,1,[+1 -1 +3 -3]); 
y1=squeeze(x); 
a=amodce(y1,Fs,'qam');    %qam modulated information 
y2=a.'; 
z1=[y2(1:c1/2),zeros(1,3*c1),y2(c1/2+1:c1)]; %4 oversample 
w1=ifft(z1);             
w1=w1*c1; 
x2=(abs(w1)).^2; 
m1=mean(x2); 
v1=max(x2); 
papr(i)=10*log10(v1/m1); 
y3=abs(w1); 
CR=1.4; 
A=CR*sqrt(2)*std(w1);       % CR=Amax/sqrt(Pin);  Pin:the input power of the ofdm signal before clipping  
w2=w1; 
for h=1:4*c1; 
    if y3(h)>A 
        w2(h)=A*w1(h)/y3(h); 
    end 
end  
x3=(abs(w2)).^2; 
m2=mean(x3); 
v2=max(x3); 
papr0(i)=10*log10(v2/m2); 
for j=1:91; 
    if papr(i)>MM(j); 
        ccdf1(j)=ccdf1(j)+1; 
    end 
    if papr0(i)>MM(j); 
        ccdf2(j)=ccdf2(j)+1; 
    end 
end 
end 
[c,d]=butter(6,0.5); 
w3=filter(c,d,w2); 
 
 
MM=1:.1:10; 
 ccdf0=ccdf1./n1; 
 ccdf3=ccdf2./n1; 
 semilogy(MM,ccdf0,'r-',MM,ccdf3,'b-'); 
 title('clipping的CCDF曲线比较') 
xlabel('papr(dB)'),ylabel('ccdf') 
legend('clipping前','clipping后',2)