In wireless mobile network signal transmitted by the transmitter towards receiver is vulnerable to many performance degrading factors like distortion, noise, fading, nonlinear distortion and so on because of physical nature of channel. To compensate these performance degrading factors, accurate prediction and estimation must be used for getting a optimized performance of the wireless mobile network. Number of Channel Estimation techniques have been developed. In this article, review of some of the channel estimation techniques have been done under many categories.