combiner.m

stbc for flat rayleigh fading channel

function S=combiner(Nr,H,rec)

if(Nr==1)
    S1=rec(1,1)*conj(H(1,1))+conj(rec(1,2))*H(1,2); % rec(receving antenna , time slot),H(receiving antenna,transmiting antenna)
    S2=rec(1,1)*conj(H(1,2))-conj(rec(1,2))*H(1,1);
    S=[S1 S2]/2;
elseif(Nr==2)
    S1=rec(1,1)*conj(H(1,1))+rec(2,1)*conj(H(2,1))+conj(rec(1,2))*H(1,2)+conj(rec(2,2))*H(2,2); % rec(receving antenna , time slot),H(receiving antenna,transmiting antenna)
    S2=rec(1,1)*conj(H(1,2))+rec(2,1)*conj(H(2,2))-conj(rec(1,2))*H(1,1)-conj(rec(2,2))*H(2,1);
    S=[S1 S2]/4;
elseif(Nr==4)
    S1=rec(1,1)*conj(H(1,1))+rec(2,1)*conj(H(2,1))+rec(3,1)*conj(H(3,1))+rec(4,1)*conj(H(4,1))...   % rec(receive antenna,time slot)
      +rec(1,2)*conj(H(1,2))+rec(2,2)*conj(H(2,2))+rec(3,2)*conj(H(3,2))+rec(4,2)*conj(H(4,2))...   % H(receive antenna,transmit antenna)
      +rec(1,3)*conj(H(1,3))+rec(2,3)*conj(H(2,3))+rec(3,3)*conj(H(3,3))+rec(4,3)*conj(H(4,3))...
      +rec(1,4)*conj(H(1,4))+rec(2,4)*conj(H(2,4))+rec(3,4)*conj(H(3,4))+rec(4,4)*conj(H(4,4))...
      +conj(rec(1,5))*(H(1,1))+conj(rec(2,5))*(H(2,1))+conj(rec(3,5))*(H(3,1))+conj(rec(4,1))*(H(4,1))...   
      +conj(rec(1,6))*(H(1,2))+conj(rec(2,6))*(H(2,2))+conj(rec(3,6))*(H(3,2))+conj(rec(4,2))*(H(4,2))...
      +conj(rec(1,7))*(H(1,3))+conj(rec(2,7))*(H(2,3))+conj(rec(3,7))*(H(3,3))+conj(rec(4,3))*(H(4,3))...
      +conj(rec(1,8))*(H(1,4))+conj(rec(2,8))*(H(2,4))+conj(rec(3,8))*(H(3,4))+conj(rec(4,4))*(H(4,4));
    S2=rec(1,1)*conj(H(1,2))+rec(2,1)*conj(H(2,2))+rec(3,1)*conj(H(3,2))+rec(4,1)*conj(H(4,2))...   % rec(receive antenna,time slot)
      -rec(1,2)*conj(H(1,1))-rec(2,2)*conj(H(2,1))-rec(3,2)*conj(H(3,1))-rec(4,2)*conj(H(4,1))...   % H(receive antenna,transmit antenna)
      -rec(1,3)*conj(H(1,4))-rec(2,3)*conj(H(2,4))-rec(3,3)*conj(H(3,4))-rec(4,3)*conj(H(4,4))...
      +rec(1,4)*conj(H(1,3))+rec(2,4)*conj(H(2,3))+rec(3,4)*conj(H(3,3))+rec(4,4)*conj(H(4,3))...
      +conj(rec(1,5))*(H(1,2))+conj(rec(2,5))*(H(2,2))+conj(rec(3,5))*(H(3,2))+conj(rec(4,1))*(H(4,2))...   
      -conj(rec(1,6))*(H(1,1))-conj(rec(2,6))*(H(2,1))-conj(rec(3,6))*(H(3,1))-conj(rec(4,2))*(H(4,1))...
      -conj(rec(1,7))*(H(1,4))-conj(rec(2,7))*(H(2,4))-conj(rec(3,7))*(H(3,4))-conj(rec(4,3))*(H(4,4))...
      +conj(rec(1,8))*(H(1,3))+conj(rec(2,8))*(H(2,3))+conj(rec(3,8))*(H(3,3))+conj(rec(4,4))*(H(4,3));
    S3=rec(1,1)*conj(H(1,3))+rec(2,1)*conj(H(2,3))+rec(3,3)*conj(H(3,3))+rec(4,3)*conj(H(4,3))...   % rec(receive antenna,time slot)
      +rec(1,2)*conj(H(1,4))+rec(2,2)*conj(H(2,4))+rec(3,4)*conj(H(3,4))+rec(4,4)*conj(H(4,4))...   % H(receive antenna,transmit antenna)
      -rec(1,3)*conj(H(1,1))-rec(2,3)*conj(H(2,1))-rec(3,1)*conj(H(3,1))-rec(4,1)*conj(H(4,1))...
      -rec(1,4)*conj(H(1,2))-rec(2,4)*conj(H(2,2))-rec(3,2)*conj(H(3,2))-rec(4,2)*conj(H(4,2))...
      +conj(rec(1,5))*(H(1,3))+conj(rec(2,5))*(H(2,3))+conj(rec(3,5))*(H(3,3))+conj(rec(4,1))*(H(4,3))...   
      +conj(rec(1,6))*(H(1,4))+conj(rec(2,6))*(H(2,4))+conj(rec(3,6))*(H(3,4))+conj(rec(4,2))*(H(4,4))...
      -conj(rec(1,7))*(H(1,1))-conj(rec(2,7))*(H(2,1))-conj(rec(3,7))*(H(3,1))-conj(rec(4,3))*(H(4,1))...
      -conj(rec(1,8))*(H(1,2))-conj(rec(2,8))*(H(2,2))-conj(rec(3,8))*(H(3,2))-conj(rec(4,4))*(H(4,2));
    S4=rec(1,1)*conj(H(1,4))+rec(2,1)*conj(H(2,4))+rec(3,1)*conj(H(3,4))+rec(4,1)*conj(H(4,4))...   % rec(receive antenna,time slot)
      -rec(1,2)*conj(H(1,3))-rec(2,2)*conj(H(2,3))-rec(3,2)*conj(H(3,3))-rec(4,2)*conj(H(4,3))...   % H(receive antenna,transmit antenna)
      +rec(1,3)*conj(H(1,2))+rec(2,3)*conj(H(2,2))+rec(3,3)*conj(H(3,2))+rec(4,3)*conj(H(4,2))...
      -rec(1,4)*conj(H(1,1))-rec(2,4)*conj(H(2,1))-rec(3,4)*conj(H(3,1))-rec(4,4)*conj(H(4,1))...
      +conj(rec(1,5))*(H(1,4))+conj(rec(2,5))*(H(2,4))+conj(rec(3,5))*(H(3,4))+conj(rec(4,1))*(H(4,4))...   
      -conj(rec(1,6))*(H(1,3))-conj(rec(2,6))*(H(2,3))-conj(rec(3,6))*(H(3,3))-conj(rec(4,2))*(H(4,3))...
      +conj(rec(1,7))*(H(1,2))+conj(rec(2,7))*(H(2,2))+conj(rec(3,7))*(H(3,2))+conj(rec(4,3))*(H(4,2))...
      -conj(rec(1,8))*(H(1,1))-conj(rec(2,8))*(H(2,1))-conj(rec(3,8))*(H(3,1))-conj(rec(4,4))*(H(4,1));
  S=[S1 S2 S3 S4]/32;
end