Is zero forcing Optimization technique or Equalization technique?
Zero-forcing is not an optimiziation technique and neither an equalization technique. It is simply one of several possible criteria to design (or optimize) an equalizer. A zero-forcing equalizer is designed to completely remove intersymbol interference, but does not take noise into account. Another, more practical criterion is the MSE (mean-square error) criterion, which results in an equalizer that minimizes intersymbol interference and reduces noise power at the same time.

I would suggest you consult one of the many good books on digital communication to learn more about this quite complex topic. Here are just two which I like:


Digital Communication by Lee and Messerschmitt
Digital Communications by Proakis