On the estimation of doubly-selective fading channels

Coherent communications over doubly-selective fading channels are attracting increasing research interests because of the performance advantage over their noncoherent counterparts. In this paper, we use a simple windowing and de-widowing technique to improve the accuracy of existing basis expansion model (BEM) and develop a windowed least-squares (WLS) estimator for doubly-selective fading channels. Our designs can considerably improve the channel estimation performance. We also design the optimum pilot patten for the WLS estimator. Simulations are provided to corroborate our theoretical analysis.