As long as the channel impulse response is less than the duration of
the cyclical prefix, there should be no inter-symbol interference. In
this case the receiver need only remove the cyclical prefix samples and
conduct an FFT for demodulation of the symbol.

Should this not be the case as is usually expected, the receiver needs
to compensate by creating a time-domain equalizer (TEQ) at the front
end. In truth, the purpose of the TEQ is to create an overall shortened
impulse response when placed in series with the actual channel that
ordinarily has a impuse response longer than the CP.

There are any number of methods of computing the TEQ, all with various
tradeoffs.

Good luck.

-V