Stereophonic acoustic echo cancellation using lattice orthogonalization

Stereophonic teleconferencing provides more natural acoustic perception by virtue of its enhanced sound localization. Of paramount importance is stereo acoustic echo cancellation (SAEC) that poses a difficult challenge to low complexity adaptive algorithms to achieve acceptable AEC due, mainly, to the strong cross-correlation between the two-channel input signals. This paper proposes a transform domain two-channel lattice algorithm that inherently decorrelates the stereo signals. The algorithm, however, bears a high computational complexity for large filter orders, N. A low complexity O(4N) algorithm is developed based on employing the functionality of the two-channel lattice cell in the previous algorithm in a weighted subband scheme. The algorithm is capable of producing complete orthogonal subbands of the stereo signals, and also allows for a tradeoff between performance and complexity. The performance of the proposed algorithms is compared with other existing algorithms via simulations and using actual teleconferencing room impulse responses.