A low-complexity doubletalk detector for acoustic echo cancellers in packet-based telephony

This paper investigates a normalized cross-correlation-based doubletalk detector for acoustic echo cancellers. A novel low-complexity version is presented suitable for implementation on IP-enabled telephones employing LPC-based speech coders. In particular, the algorithm obtains a decorrelated input signal and decorrelation filter coefficients directly from the speech decoder. The proposed algorithm is implemented using ITU G.729, and simulation results are collected for a typical room. Calibration data are obtained and shown to be independent of the speech input signal. It is also shown that the proposed algorithm has the same performance as a full-complexity version employing the same decorrelation filter order.