Reduced complexity channel estimation for wireless communication systems

Abstract

Techniques to derive a channel estimate using substantially fewer number of complex multiplications than with a brute-force method to derive the same channel estimate. In one method, an intermediate vector B is initially derived based on K sub-vectors of a vector Ĥ for a channel frequency response estimate and at least two DFT sub-matrices for a DFT matrix {tilde over (W)}, where K>1. An intermediate matrix A for the DFT matrix {tilde over (W)} is also obtained. A least square channel impulse response estimate is then derived based on the intermediate vector B and the intermediate matrix A. In one implementation, the intermediate vector B is obtained by first computing DFTs of a matrix Ĥ, which is formed based on the vector Ĥ, to provide a matrix G. Inner products between the columns of a base DFT sub-matrix Wand the rows of the matrix Gare then computed to obtain the entries of the intermediate vector B.