What is the time reversal convolution Given a signal $r(t)$ which is a result of convolution between signal $x(t)$ and a channel $h(t)$ as below : 

$r(t) = h(t)*x(t); $   

what I know, the time reversal convolution can be process as follows : 
$y(t) = r(t)*h^*(-t) = h(t)*x(t)*h^H(-t);$ where * denote to the convolution and $h^H$ is the conjugate. I think that right and clear, but what does mean $h(-t)$.  is it all simply equals to $conv(r(t), -h(t))$ for example as below : 

x = randn(1,5);
h = randn(1,3);
r = conv(h,x);
y = conv(r,-h);


Is y is correct in the above example? however I think it should be continuous where the above example is discrete signal.
I believe that h(-t) means a "time-reversed" version of h(t). Your command: 'y = conv(r,-h);' computes the convolution of 'r' and negative 'h', and you don't want that. I think you want: 

y = conv(r,conj(fliplr(h)));