A throughput improvement scheme for asymmetrical digital subscriber line (ADSL) transceivers

Echo cancellation technique enables full duplex transmission using the same transmission band and thereby increases the aggregate data throughput of a channel. This tutorial paper introduces high speed echo cancellation for Full Rate (ITU-T Recommendation G.992.1) and Splitterless (ITU-T Recommendation G.992.2, aliased G.Lite) ADSL Transceivers. Symmetric and multirate Asymmetric echo cancellation Transceiver structures based completely on time domain or frequency domain as well as both time and frequency domain echo cancellation have been analyzed using different algorithms for performance and computational complexity. Combined Time and Frequency Domain Echo Cancellation (TAFDEC) structure with the so called DMT algorithm appears to be most suitable to achieve lower complexity with better performance as compared to echo cancellation in either time or frequency domain using LMS algorithm.