Single carrier modulation technology for very high-speed digital subscriber line

This article gives an overview of very high-speed digital subscriber lines, including the main issues of VDSL system design, such as its basic architecture, applications, and data rates, as well as the technological challenges of practical implementation due to different loop plant realities and spectral compatibility considerations. Some specific characteristics of the VDSL transceiver startup procedure and high-level architecture, as well as a summary of first laboratory tests and field trials, are also presented. The article concentrates on VDSL implementations using single-carrier modulation, which integrates the well-known carrierless amplitude/phase modulation and quadrature amplitude modulation technologies. Currently, SCM technology is considered one of the main candidates for the VDSL standard in the United States and Europe, and internationally.