An efficient multichannel line echo canceler algorithm for PSTN and VoIP/VoDSL applications

This paper proposes an efficient multichannel line echo canceler algorithm with interchannel distribution of computations. A limited number of coefficient adaptations are distributed among channels depending on the degree of convergence and the input signal power to achieve up to 50% reduction of total computations. Coefficient adaptations are more frequently performed in the channels where convergence is behind others and there is a sufficient input power. As the index to the degree of convergence, an averaged sum of squared coefficients is used. Its gradient weighted with the input signal power is evaluated for interchannel distribution of coefficient adaptations. Simulation results with white Gaussian signals and speech signals demonstrate good convergence. The efficiency of coefficient adaptations is improved by 30% over the conventional algorithm. The computational savings can be used to accommodate more channels on the same chip, or to cover a longer echo-path with additional delays by codecs and/or ATM cell assembly/disassembly. It is also promising for analog interface in IAD and SOHO routers for VoIP/VoDSL applications.