Abstract: Channel equalizers are used to reduce the Inter-Symbols Interference (ISI) arising from the delay spread or band-limitation of the channel by modifying the pulse shape, so that, it does not interfere with the nearby pulses. Major equalization techniques are linear equalization, Viterbi Maximum-Likelihood Sequence Estimation (MLSE) and Decision-Feedback Equalization (DFE). These receivers for frequency-selective channels can be easily extended to multiple antenna cases. Classical channel equalization methods such as the linear equalizer and the DFE are based on training sequences. There are some blind algorithms which avoid the use of training sequences. So that, led us to Maximum Likelihood Sequence Estimation (MLSE) is the best form of sequence exposure but is extremely complex and having the smallest probability of detecting the incorrect sequence.