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 vectoris initially derived based on K sub-vectors of a vector {circumflex over ()} for a channel frequency response estimate and at least two DFT sub-matrices for a DFT matrix {tilde over ()}, where K>1. An intermediate matrixfor the DFT matrix {tilde over ()} is also obtained. A least square channel impulse response estimate is then derived based on the intermediate vectorand the intermediate matrix. In one implementation, the intermediate vectoris obtained by first computing DFTs of a matrix, which is formed based on the vector {circumflex over ()}, to provide a matrix. Inner products between the columns of a base DFT sub-matrixand the rows of the matrixare then computed to obtain the entries of the intermediate vector.