val_r.m

LDPC码的BP算法译码MATLAB程序

function[R]=val_R(Lq)
for j=1:length(Lq(:,1))
for i=1:length(Lq(1,:))                                            %确定符号
  if Lq(j,i)<=0                        
       sgn(j,i)=-1;
   else
       sgn(j,i)=1;
   end;       
end;
end;

Lq=abs(Lq);               %取绝对值

R(1,1)=-sgn(1,3)*sgn(1,8)*sgn(1,9)*min([Lq(1,3),Lq(1,8),Lq(1,9)]);
R(3,1)=-sgn(3,4)*sgn(3,5)*sgn(3,11)*min([Lq(3,4),Lq(3,5),Lq(3,11)]);
R(6,1)=-sgn(6,12)*sgn(6,13)*sgn(6,14)*min([Lq(6,12),Lq(6,13),Lq(6,14)]);

R(4,2)=-sgn(4,8)*sgn(4,11)*sgn(4,12)*min([Lq(4,8),Lq(4,11),Lq(4,12)]);
R(4,2)=-sgn(4,3)*sgn(4,7)*sgn(4,13)*min([Lq(4,3),Lq(4,7),Lq(4,13)]);
R(11,2)=-sgn(11,6)*sgn(11,18)*sgn(11,19)*min([Lq(11,6),Lq(11,18),Lq(11,19)]);

R(1,3)=-sgn(1,1)*sgn(1,8)*sgn(1,9)*min([Lq(1,1),Lq(1,8),Lq(1,9)]);
R(5,3)=-sgn(5,2)*sgn(5,7)*sgn(5,13)*min([Lq(5,2),Lq(5,7),Lq(5,13)]);
R(8,3)=-sgn(8,4)*sgn(8,10)*sgn(8,16)*min([Lq(8,4),Lq(8,10),Lq(8,16)]);

R(3,4)=-sgn(3,1)*sgn(3,5)*sgn(3,11)*min([Lq(3,1),Lq(3,5),Lq(3,11)]);
R(8,4)=-sgn(8,3)*sgn(8,10)*sgn(8,16)*min([Lq(8,3),Lq(8,10),Lq(8,16)]);
R(13,4)=-sgn(13,8)*sgn(13,19)*sgn(13,20)*min([Lq(13,8),Lq(13,19),Lq(13,20)]);

R(2,5)=-sgn(2,6)*sgn(2,7)*sgn(2,10)*min([Lq(2,6),Lq(2,7),Lq(2,10)]);
R(3,5)=-sgn(3,1)*sgn(3,4)*sgn(3,11)*min([Lq(3,1),Lq(3,4),Lq(3,11)]);
R(15,5)=-sgn(15,9)*sgn(15,17)*sgn(15,19)*min([Lq(15,9),Lq(15,17),Lq(15,19)]);

R(2,6)=-sgn(2,5)*sgn(2,7)*sgn(2,10)*min([Lq(2,5),Lq(2,7),Lq(2,10)]);
R(11,6)=-sgn(11,2)*sgn(11,18)*sgn(11,19)*min([Lq(11,2),Lq(11,18),Lq(11,19)]);
R(12,6)=-sgn(12,15)*sgn(12,17)*sgn(12,20)*min([Lq(12,15),Lq(12,17),Lq(12,20)]);

R(2,7)=-sgn(2,5)*sgn(2,6)*sgn(2,10)*min([Lq(2,5),Lq(2,6),Lq(2,10)]);
R(5,7)=-sgn(5,2)*sgn(5,3)*sgn(5,13)*min([Lq(5,2),Lq(5,3),Lq(5,13)]);
R(9,7)=-sgn(9,14)*sgn(9,16)*sgn(9,17)*min([Lq(9,14),Lq(9,16),Lq(9,17)]);

R(1,8)=-sgn(1,1)*sgn(1,3)*sgn(1,9)*min([Lq(1,1),Lq(1,3),Lq(1,9)]);
R(4,8)=-sgn(4,2)*sgn(4,11)*sgn(4,12)*min([Lq(4,2),Lq(4,11),Lq(4,12)]);
R(13,8)=-sgn(13,4)*sgn(13,19)*sgn(13,20)*min([Lq(13,4),Lq(13,19),Lq(13,20)]);%%

R(1,9)=-sgn(1,1)*sgn(1,3)*sgn(1,8)*min([Lq(1,1),Lq(1,3),Lq(1,8)]);
R(7,9)=-sgn(7,10)*sgn(7,12)*sgn(7,15)*min([Lq(7,10),Lq(7,12),Lq(7,15)]);
R(15,9)=-sgn(15,5)*sgn(15,17)*sgn(15,19)*min([Lq(15,5),Lq(15,17),Lq(15,19)]);

R(2,10)=-sgn(2,5)*sgn(2,6)*sgn(2,7)*min([Lq(2,5),Lq(2,6),Lq(2,7)]);
R(7,10)=-sgn(7,9)*sgn(7,12)*sgn(7,15)*min([Lq(7,9),Lq(7,12),Lq(7,15)]);
R(8,10)=-sgn(8,3)*sgn(8,4)*sgn(8,16)*min([Lq(8,3),Lq(8,4),Lq(8,16)]);

R(3,11)=-sgn(3,1)*sgn(3,4)*sgn(3,5)*min([Lq(3,1),Lq(3,4),Lq(3,5)]);
R(4,11)=-sgn(4,2)*sgn(4,8)*sgn(4,12)*min([Lq(4,2),Lq(4,8),Lq(4,12)]);
R(10,11)=-sgn(10,14)*sgn(10,15)*sgn(10,18)*min([Lq(10,14),Lq(10,15),Lq(10,18)]);

R(4,12)=-sgn(4,2)*sgn(4,8)*sgn(4,11)*min([Lq(4,2),Lq(4,8),Lq(4,11)]);
R(6,12)=-sgn(6,1)*sgn(6,13)*sgn(6,14)*min([Lq(6,1),Lq(6,13),Lq(6,14)]);
R(7,12)=-sgn(7,9)*sgn(7,10)*sgn(7,15)*min([Lq(7,9),Lq(7,10),Lq(7,15)]);

R(5,13)=-sgn(5,2)*sgn(5,3)*sgn(5,7)*min([Lq(5,2),Lq(5,3),Lq(5,7)]);
R(6,13)=-sgn(6,1)*sgn(6,12)*sgn(6,14)*min([Lq(6,1),Lq(6,12),Lq(6,14)]);
R(14,13)=-sgn(14,16)*sgn(14,18)*sgn(14,20)*min([Lq(14,16),Lq(14,18),Lq(14,20)]);

R(6,14)=-sgn(6,1)*sgn(6,12)*sgn(6,13)*min([Lq(6,1),Lq(6,12),Lq(6,13)]);
R(9,14)=-sgn(9,7)*sgn(9,16)*sgn(9,17)*min([Lq(9,7),Lq(9,16),Lq(9,17)]);
R(10,14)=-sgn(10,11)*sgn(10,15)*sgn(10,18)*min([Lq(10,11),Lq(10,15),Lq(10,18)]);

R(7,15)=-sgn(7,9)*sgn(7,10)*sgn(7,12)*min([Lq(7,9),Lq(7,10),Lq(7,12)]);
R(10,15)=-sgn(10,11)*sgn(10,14)*sgn(10,18)*min([Lq(10,11),Lq(10,14),Lq(10,18)]);
R(12,15)=-sgn(12,6)*sgn(12,17)*sgn(12,20)*min([Lq(12,6),Lq(12,17),Lq(12,20)]);

R(8,16)=-sgn(8,3)*sgn(8,4)*sgn(8,10)*min([Lq(8,3),Lq(8,4),Lq(8,10)]);
R(9,16)=-sgn(9,7)*sgn(9,14)*sgn(9,17)*min([Lq(9,7),Lq(9,14),Lq(9,17)]);
R(14,16)=-sgn(14,13)*sgn(14,18)*sgn(14,20)*min([Lq(14,13),Lq(14,18),Lq(14,20)]);

R(9,17)=-sgn(9,7)*sgn(9,14)*sgn(9,16)*min([Lq(9,7),Lq(9,14),Lq(9,16)]);
R(12,17)=-sgn(12,6)*sgn(12,15)*sgn(12,20)*min([Lq(12,6),Lq(12,15),Lq(12,20)]);
R(15,17)=-sgn(15,5)*sgn(15,9)*sgn(15,19)*min([Lq(15,5),Lq(15,9),Lq(15,19)]);

R(10,18)=-sgn(10,11)*sgn(10,14)*sgn(10,15)*min([Lq(10,11),Lq(10,14),Lq(10,15)]);
R(11,18)=-sgn(11,2)*sgn(11,6)*sgn(11,19)*min([Lq(11,2),Lq(11,6),Lq(11,19)]);
R(14,18)=-sgn(14,13)*sgn(14,16)*sgn(14,20)*min([Lq(14,13),Lq(14,16),Lq(14,20)]);

R(11,19)=-sgn(11,2)*sgn(11,6)*sgn(11,18)*min([Lq(11,2),Lq(11,6),Lq(11,18)]);
R(13,19)=-sgn(13,4)*sgn(13,8)*sgn(13,20)*min([Lq(13,4),Lq(13,8),Lq(13,20)]);
R(15,19)=-sgn(15,5)*sgn(15,9)*sgn(15,17)*min([Lq(15,5),Lq(15,9),Lq(15,17)]);

R(12,20)=-sgn(12,6)*sgn(12,15)*sgn(12,17)*min([Lq(12,6),Lq(12,15),Lq(12,17)]);
R(13,20)=-sgn(13,4)*sgn(13,8)*sgn(13,19)*min([Lq(13,4),Lq(13,8),Lq(13,19)]);
R(14,20)=-sgn(14,13)*sgn(14,16)*sgn(14,18)*min([Lq(14,13),Lq(14,16),Lq(14,18)]);

R=-R;