The effects of vectored DSL on network operations

摘要

The well-known benefit of vectored digital subscriber line (vectored DSL) is that it achieves data rates approaching 100 megabits per second (Mbps) by eliminating crosstalk noise, thus enabling the offering of high-end services on copper pairs. Such data rates compare favourably with the end-user data rates practically achievable in fibre-to-the-home (FTTH) or cable deployments, but with a substantially more modest capital investment as vectored DSL services are delivered over existing copper infrastructure. This paper studies the effects of deploying vectored DSL, and identifies benefits to the network operations processes of DSL service providers including line diagnostics and automatic line repair. It explains that properly deployed vectored DSL improves the accuracy of estimating the locations of cable faults and predicting data-rate performance through improved line diagnostic functions. It also shows how an automatic line repair function can prevent customer calls and technician dispatches by properly mitigating the effects of both impulsive and stationary noise sources. Automatic line repair can also achieve coexistence of vectored DSL with older DSL types sharing the same binder. The paper proceeds to discuss certain deployment issues such as the differences between deploying from a small node (ie DSL access multiplexer (DSLAM)) versus a large node of 100 pairs or more. The latter case can be more cost-effective, but requires additional functionality for ensuring that crosstalk among all pairs can be effectively cancelled. Finally, the choices for deploying vectored DSL in an unbundled environment are presented. It is explained that, in such cases, the benefits of vectored DSL are maximised when certain management functions are shared by all service providers with access to the node.