An Investigation of an Adaptive IIR Echo Canceller: Advantages and Problems

Most existing echo cancellers are designed with adaptive FIR digital filters. In this paper, a recently developed adaptive IIR filtering algorithm [32], [33] is used to implement an adaptive IIR echo canceller. The simplicity and the proved convergence of the algorithm make it attractive for this application. The advantages in using the adaptive IIR echo canceller are discussed as well as some remaining problems. Extensive computer simulations show that the IIR canceller performs better than the FIR canceller after convergence, although in general the IIR canceller converges more slowly. It is also observed that the order selection of the IIR canceller is crucial in achieving superior performance over FIR cancellers.