In communication systems with high data rates, Intersymbol Interference (ISI) is a major problem (ISI).
I have read in books that one way to combat this problem is to use time domain equalizers (ZF, MMSE, DFE) at the receivers or frequency domain equalizers (ZF, MMSE).
I am just here to ask whether my understanding is correct.
- Are we using the equalizers to compensate for the channel impulse response (in case time domain) or channel transfer function (frequency domain equalizers) and therefore we are combating ISI?
- If yes, why is it that by compensating for the channel we are getting rid of ISI?
- In order to obtain this time domain filter or transfer function we should have estimated the channel before hand?
- Is the output of the equalizers are estimated symbols of what has been transmitted?
I would appreciate helping me out in this confusion of ideas maybe with an example.