Basis Expansion Model for Fast Time-Varying Channel Estimation in High Mobility Scenarios

In order to provide the users with reliable wireless communication service in high-speed mobility scenarios, we need to obtain channel state information by channel estimation. However, the wireless channel presents a characteristic of dynamic change in high-speed mobility environments. It will bring great challenge to channel estimation. Aiming at the high-speed railway communication system, the issue of the fast time-varying channel estimation is investigated in this paper. The impulse response of the fast time-varying channel is modeled as the product of the basis functions and the coefficients by introducing a basis expansion model (BEM). Meanwhile, the comb pilot clusters are inserted in frequency domain. The coefficients of basis functions are derived by the least-square estimation criterion so as to realize the estimation of the channel impulse response. Simulation results show that optimization generalized complex exponential BEM (OGCE-BEM) has the smallest normalized mean square error among the various types of BEMs.