Blind Crosstalk Channel Estimation for Multi-User Digital Subscriber Lines

Abstract-This paper presents a blind method for estimating both the insertion loss and crosstalk channel in multi-user Digital Subscriber Line (DSL) systems. Based on cyclostationary properties of Discrete Multi-tone (DMT) signal, we select appropriate cyclic suffix length of DMT signal in the transmitter side such that the receiver reserves the insertion loss channel information of the discussed line and crosstalk channels information from other lines on the chosen tone, while the insertion loss channel effects from other lines and the crosstalk effect on the current line from other users on the chosen tone are all zeros. Then the insertion loss and crosstalk channels can respectively be estimated from received data on each line. Computer simulation results based on real measured data verify that the proposed method can estimate both the insertion loss and crosstalk channels. Furthermore, compared to the previous works, the new method has lower estimation errors and is easy to be implemented.