Maximum likelihood estimation of time delays in multipath acoustic channel

This paper presents a solution to the problem of time delay estimation in multipath acoustic channel. Here the multipath acoustic channel output signal is modelled as a superposition of the delayed, attenuated, and filtered version of the stationary Gaussian stochastic input signal. A maximum likelihood (ML) estimator is developed for determining time delays in multipath acoustic channel in the presence of uncorrelated noise. Accuracy percentage (AP) performance measure has been introduced to characterize the performance of the estimators. The performance of the ML estimator is compared via computer simulation, using AP, with a generalized autocorrelation estimator (GAE) and AP(CRLB) which is obtained by expressing the CRLB in terms of probability. Simulation results show that the performance of the ML estimator is superior to the GAE and approaches to AP(CRLB). The robustness of the algorithm has also been studied via computer simulation. (C) 2009 Elsevier B.V. All rights reserved.