Estimation of Fading Coefficients in the Presence of Multipath Propagation

In order to get the information about multipath propagation, this communication presents two estimation methods for slowly varying fading coefficients. With known numbers of the far-field sources and multipaths from each far-field source, the fading coefficients in multipath propagation can be well estimated. The methods not only have low complexity but also have high performance, and the fading coefficients can be resolved directly without a searching procedure. Afterwards, we make an extension to further improve the estimation accuracy of both direction of arrival (DOA) and fading coefficients after obtaining their estimations. The Cramer-Rao bound (CRB) for this problem is also deduced. Simulation results demonstrate the effectiveness and efficiency of the proposed methods.