r3_4bldpc.m

generate LDPC systemetic metrix

%base model matrix for Rate 3/4B LDPC code represented in wimax802.16
Hbm=[-1 81 -1 28 -1 -1 14 25 17 -1 -1 85 29 52 78 95 22 92  0  0 -1 -1 -1 -1
     42 -1 14 68 32 -1 -1 -1 -1 70 43 11 36 40 33 57 38 24 -1  0  0 -1 -1 -1
     -1 -1 20 -1 -1 63 39 -1 70 67 -1 38  4 72 47 29 60  5 80 -1  0  0 -1 -1
     64  2 -1 -1 63 -1 -1  3 51 -1 81 15 94  9 85 36 14 19 -1 -1 -1  0  0 -1
     -1 53 60 80 -1 26 75 -1 -1 -1 -1 86 77  1  3 72 60 25 -1 -1 -1 -1  0  0
     77 -1 -1 -1 15 28 -1 35 -1 72 30 68 85 84 26 64 11 89  0 -1 -1 -1 -1  0];
 R=3/4;%code rate
 cols=1152;% system matrix H's columns
 %cols=1152;% system matrix H's columns
 rows=cols*(1-R);% system matrix H's rows
 z=cols/24;%code length n=1152
 H=sparse(rows,cols,0);%system matrix m by n
 for r=1:24*(1-R)
     for c=1:24
         hr=1+(r-1)*z;
         hc=1+(c-1)*z;
         if Hbm(r,c)>=0
              H(hr:hr+z-1,hc:hc+z-1)=circshift(eye(z),[0,Hbm(r,c)]);
         end
     end
 end
 save irregular.mat H;