Adaptive echo cancellation in cellular networks

The miscalculation of the delay between the near end and the far end sections of the echo canceller is one of the main causes of the uncancelled echo in voice communications often heard during international, long distance, and digital wireless calls. Also, in mobile communications, the channel is not stationary, which results in variation of the delay between the near end and the far end sections of the echo canceller. In this work an LMS-based algorithm based on smooth transition bands (at the end of the near end and at the beginning of the far end sections) is proposed to overcome the above problem. Transient and steady-state behavior and convergence conditions are studied. A comparison of the new algorithm with that using the sharp transition is also given. Simulation results show great improvement of performance of the proposed scheme over the used ones.