LMS implementatiom for echo cancelation ad co-channel interference supression

I am working on a project in which, based on the LMS adaptive algorithm, I
have to perform the following: echo cancelation and co-channel
interference supression. I have tried the inplementation of the algorithm
in Mathlab but for noise cancelation. For noise cancelation it was was
simple:

d = awgn(x, 22);// signal distorted by noise SNR is -22 dB
mu = 0.08;//step size
ha = adaptfilt.lms(20, mu);//the lms filter
[yy, ee] = filter(ha, x, d);//yy is the filtered signal

But how can I model the echo signal(for echo cancelation)?I know it is a
delayed and attenuated version of the initial signal but I need a
mathematical model.

If this correct?  d = x + x(n+delay)/attenuation factor.

As for co-channel interference supression i need more help.I am in dark on
this one.

Are you working on an ATSC TV receiver?

Adaptive Eq does not normally help against co-channel intereference
when the interfrerring signal is the same kind of signal as the
desired....But an adaptive EQ in an ATSC TV recevier can help against
co-channnel interference if the desired signal is a digital ATSC signal
and the interfererer is an NTSC analog TV signal.  This is because, in
this case,  the interference is concentrated in a few small frequency
ranges and the EQ filter can create notches at those frequencies.

Mark