Low complexity MIMO channel estimation for FEXT precompensation in vectored xDSL systems

Far-end Crosstalk (FEXT) is the major limiting factor in further increase of data rate in xDSL systems. Hopefully, FEXT can be easily removed by modelling transmission channel as MIMO channel and applying vectored transmission. Having the knowledge of MIMO channel transfer function, FEXT can be completely cancelled by appropriate pre-distortion of transmitted signals. Therefore, in the paper we propose low complexity MIMO channel estimator employing Set-Membership Adaptive Recursive Techniques (SMART) with additional DFT based interpolation. As it is shown, proposed method is very accurate enabling systems with FEXT pre-compensation to approach performance of the ones operating on FEXT free channel. It is also efficient in terms of required amount of training data.