Dual Transform Domain Echo Canceller for Discrete Multitone Systems

In communication systems where full-duplex transmission is required, digital echo cancellers are employed to cancel echo by means of adaptive filtering. In order to reduce the computational complexity of these cancellers, the structure of the Toeplitz matrix containing the transmitted signal is usually exploited to transform the time domain signals and perform the emulation and adaptive update in a more convenient domain (e.g. frequency domain). In this paper, we consider a general decomposition of the Toeplitz matrix and examine the effect of different components of the decomposition on the computational complexity and convergence behaviour of the canceller. Based on this general decomposition, a new dual transform domain canceller is proposed which has improved convergence compared to the current echo cancellers and also does not require the transmission of dummy data on the unused tones.