Analytical Evaluation of the Role of Estimation and Quantization Errors in Downstream Vectored VDSL Systems

The authors investigate the effect of non idealities in the diagonalizing precoder vectoring technique used for cancellation of the far-end crosstalk in downstream VDSL networks. By using analytical formulas, they estimate the average bit rate achievable as a function of both relative and absolute estimation errors. Several numerical examples are provided, in different scenarios and operation conditions. Results are presented covering an important aspect for practical applications: the transmitted power required to achieve a target bit rate, as a function of the line length. Finally, they provide some results on the impact of a smart quantization law, which limits the performance loss.