Joint delay and impulse response estimation using sliding RLS filters

Abstract

This paper considers the problem of joint time delay and impulse response estimation and its applications to, for example, echo cancellation for hybrid echos in telephone lines. The paper suggests a new algorithm based on considering the minimum mean-square error output of an RLS-type filter. The RLS filter is run for different possible test delays, and a hypothesis test is applied for each test delay to test if the true delay is within some interval around the test delay. It is shown that the algorithm has very low complexity (about the same as FTF-type filters), and the performance is investigated theoretically and through simulations. The algorithm can be used for a very low complexity echo canceller with convergence time almost as short as the echo bulk delay.