Expert System based on Wavelets and DELT Measurements for VDSL Systems

Dual-ended line testing (DELT) is a common capability in most current modems and can be used for digital subscriber line (DSL) qualification and monitoring purposes. In spite of that, this feature remains largely unexplored in the literature. This paper proposes a new method based on wavelets and DELT measurements for estimating the total length of the line under test and identification of bridged-taps, two important line parameters that affect the maximum bit rate reached by a DSL line. The proposed method was tested with measurements employing real twisted-pair cables and obtained reasonably accurate results for the analyzed cases.