%hold on;
clear all;
N=100000;
num=128;


d4s=zeros(1,12*5+1);
for i=1:2:N
   for j=1:2*num
      if randn<0
        s0(j)=1;
      else
        s0(j)=0;
      end
   end
   for k=1:2*num              
       if randn<0
        s1(k)=1;
      else
        s1(k)=0;
      end
   end
L=length(s0);

%equivalent sequence
b0=2*s0-1;
b1=2*s1-1;

%specify the phases of codes sequence
j=1;
for k=1:2:L
   x1(j)=b0(k)+b0(k+1)*sqrt(-1);
   j=j+1;
end
j=1;
for k=1:2:L
   x2(j)=b1(k)+b1(k+1)*sqrt(-1);
   j=j+1;
end

%STBC
for i=1:num
    x11(i)=-x2(i)';
    x22(i)=x1(i)';
end

   point=num;
   out_T1=sqrt(point)*sqrt(point)*ifft(x1,point);
   out_T2=sqrt(point)*sqrt(point)*ifft(x2,point);
   max_P1=(max(abs(out_T1)))^2;
   max_P2=(max(abs(out_T2)))^2;
   papr1=max_P1/(2*num);
   papr2=max_P2/(2*num);
   papr=max(papr1,papr2);
   

    k=1;
    for pap0=0:1/5:12
      if papr>10^(pap0/10)
         d4s(k)=d4s(k)+1;
      end
      k=k+1;
    end
end   
d4s=(d4s*2)/N;
pap0=0:1/5:12;

axis([5 12 10.^(-4) 1])
semilogy(pap0,d4s,'b');
xlabel('PAR0(dB)')
ylabel('Prob[PARlow>PAR0]')