Analysis of an adaptive IIR filter for multipath time delay estimation

A novel adaptive recursive algorithm is proposed for estimating the interpath delay of a radiated signal in a multipath environment. Using LMS-type adaptation, the estimator is computationally efficient and it provides direct measurements of multipath gain and delay on a sample-by-sample basis. The convergence dynamics and variances of system parameters are derived. It is shown that the optimal performance of the estimator approaches the Cramér-Rao lower bound (CRLB) for high signal-to-noise ratio (SNR) conditions. Computer simulations have validated the capability of the method to track time-varying delays accurately.