If you have a signal, x, then the matched filter's coefficients is given by time reverse of x, i.e., x(end:-1:1). If your signal is complex, you also need to to use complex conjugate. You can then use it just as an FIR filter. For example,
>> x = ones(10,1); >> b = x(end:-1:1); >> y = filter(b,1,x);
To elaborate on Honglei's answer. If the signal you are trying to design a matched filter for, is x, then --
>> b = x(end-1:1); >> y = filter(b,1,x);
You should already have x.
Hi You can try the model given here
Square Root raised Cosine - Matched filter implementation http://www.gaussianwaves.com/2011/04/square-root-raised-cosine-filter-matchedsplit-filter-implementation-2/