flag.m

convolution coding program using viterabi algorithm

function [pun]= flag(data_soft_de, rate);
% generate the flag for Viterbi decoder dealing with the dummy zeros
l = length(data_soft_de);
if rate == 1
for i=1:l
pun(l) = 0;
end
elseif rate == 2
for i=1:l
if rem (i, 4) == 0
pun(i)=1;
else pun(i)=0;
end
end
elseif rate == 3
t1 = (l-rem(l,6))/6;
for i=0:t1-1
pun(6*(i)+1)=0;
pun(6*(i)+2)=0;
pun(6*(i)+3)=1;
pun(6*(i)+4)=0;
pun(6*(i)+5)=1;
pun(6*(i)+6)=0;
end
for j =( l - rem(l,6) ):l
pun(j)=0;
end
end