How do I perform a channel with probability?

I have made an binary sequnce called r.

When 0 is presented as input, I want the channel to generate an output of 0 with 0.975 and generate an output of 1 with 0.025 probability.

And 1 the other way around.

How can I code program this?

Answer 1

[Peng Li]

% simulate a sequence r
r   = [ones(100, 1); zeros(100, 1)];
ind = randperm(length(r));
r   = r(ind);

% randsrc generate a vector of 0 or 1 with probability 0.975 and 0.025, you
% sum up two randsrc results based on r is 0 or 1, if r == 1, switch the
% parameter of randsrc so that it generates 1 with prob 0.975
res = (r == 0) .* randsrc(length(r), 1, [0 1; 0.975 0.025]) + ...
    (r == 1) .* randsrc(length(r), 1, [1 0; 0.975 0.025]);