OPTIMUM DESIGN OF THE HARD-SWITCHING DUAL SIGN ALGORITHM FOR ADAPTIVE ECHO CANCELLATION

A practical design Method is presented to optimize the hard-switching dual sign algorithm (HS-DSA), formed by the sign algorithm (SA) with a time switch for the step size, for the fastest convergence in adaptive echo cancellation. For the optimized HS-DSA, the two step sizes and the switching instant are optimally chosen to yield the most rapid convergence under fixed initial and desired residual echoes. Over the range of interest in practical applications, it is shown that the worst case initial residual echo can be used to estimate the optimum switching instant. As compared to previously known variants of the SA, the optimized HS-DSA gains improvements in convergence performance and retains the advantage of hardware simplicity. Computer simulations are employed to show the correctness and effectiveness of the algorithm.