The Channel Estimation in Mobile Wireless Systems is a technique used in estimating the time-varying channel from mobile user equipment (UE). This technique helps the mobile wireless systems to combat multipath propagation fading and Doppler shifts caused by user mobility. Channel Estimation significantly improves the performance of the mobile wireless communication systems where the channel changes over time, especially for 4G and Long Term Evolution (LTE) systems. The channel estimation helps mobile wireless systems to achieve high data rate, high capacity and reliable communication. There are different types of methods used in estimating the time-variant channel but this book explains the three common used methods in estimating the channel of Mobile Wireless Systems; Discrete Prolate Spheroidal Sequences (DPSS) or Slepian Basis Expansion, The European Union project Wireless World Initiative New Radio model (WINNER phase II) and Fourier Basis Expansion by testing, fitting of curves and investigating the Mean Square Error (MSE) using Least-Squares (LS) method.