Linearly Constrained Adaptive Echo Cancellation for Discrete Multitone Systems

Neda Ehtiati, Benoit Champagne
2007 2007 IEEE International Symposium on Signal Processing and Information Technology  
Achieving the full duplex transmission in digital sub-(or tones), and data are modulated and demodulated by the scriber lines (DSL) is possible by using echo cancellation methods. use of the inverse discrete Fourier transform (IDFT) and DFT Most of the methods available for echo cancellation, in DSL systems operations. In DMT-based systems, where we have access to based on the discrete multitone (DMT) modulation, deploy partial the presentation of the signal both in the time and frequency echo
more » ... ancellation in the time andfrequency domain. In these systems, the weights of the FIR filter emulating the echo in the time domain domain, the circular echo synthesis (CES) method, proposed are mapped from the frequency-domain adaptive echo weights. This by Ho et. al [2] , is used for emulating the echo. In this mapping can be regarded as a linear constraint on an extended weight method, the circular part of the echo is emulated and cancelled vector containing weights in the time and frequency domain, and efficiently in the frequency domain and the residual echo is echo cancellation can then be regarded as a linearly constrained optimization on this extended linear space. In this paper, linearly thecancell alsoaupdated in the tfier eingts dmain.Odheli constrained adaptive echo cancellation for DMT-based DSL systems the echo is also updated in the frequency domain. Other is proposed. Two approaches are introduced based on the adaptive methods for echo cancellation propose modifications to this algorithms by Frost and by Griffiths. The proposed structure provides echo canceller in order to lower the complexity and/or improve a unifying and flexible framework for echo cancellation in different the performance of the system. For instance in [3], Jones DSL systems. Furthermore, in the proposed method the proper choice has shown that the proper choice of the delay between the of the constraint can address the drifting problem in the presence of transmitted symbols and received symbols can reduce the the narrow band noise in the DSL systems. Keywords Echo cancellation, adaptive filtering, DMT modula-complexity of the system. In [4], Ysebaert et al. have added tion, DSL systems. double talk cancellation to the receiver, i.e. removing the effect of the far end signal, in order to improve the convergence of 978-1 -4244-1 835-0/07/$25.00 ©C2007 IEEE
doi:10.1109/isspit.2007.4458107 fatcat:rrntawgi2veffcavujevhfkzqu