A DATA-DRIVEN MULTITONE ECHO CANCELER

A data-driven echo canceller for full-duplex data transmission with multitone modulation is presented. This multi-tone echo canceller (MTEC) is not impaired by eigenvalue-spread problems that are inherent in signal-driven echo cancellers-it has numerical performance and cancellation range that equals, and in most cases exceeds, that of data-driven echo cancellers used in data transmission with baseband or quadrature amplitude modulation. The method makes use of frequency-domain updating, but time-domain implementation of the canceller. It introduces no delay into the received signal path and presents no special difficulties for interframe interpolation between near-end echo, far-end echo, or far-end data signal. We also investigate fast initialization and the special case of far-end frequency offset in the echo signal.