vectoring

Vectoring is a method used to increase the data rate in xDSL technologies, primarily in VDSL2 and ADSL2+, which is why it is also referred to as VDSL2 vectoring. Vectoring and other methods used in dynamic spectrum management( DSM), such as line bonding or phantom operation, aim to reduce and compensate for the data rate limitations caused by extraneous and interfering signals, interference, crosstalk and near-end crosstalk on the DSL lines of the local loop( ULL).

All three methods, which are also combined together, are intended to increase the transmission rate of the existing copper twisted pairs and thus delay cost-intensive optical cabling for as long as possible. While some dynamic spectrum management methods reduce transmission power or change transmission frequencies for individual DSL lines, vectoring relies on compensation for far-end crosstalk( FEXT) and interference cancellation ( IFC) to improve the interference ratio.

VDSL2 specifications with vectoring

Vectoring is a method standardized by the International Telecommunication Union( ITU) under G.993.5 for reducing interference in the connection area on the copper twisted pair. It is a compensation technique in which a compensation signal is calculated during transmission, i.e., in real time, to filter out the high- frequency interference signals. With this method, VDSL2 in accordance with ITU-T G.993.5 Annex A achieves download data rates of 100 Mbit/s over a line length of 1,000 m, and even data rates of 250 Mbit/s over 500 m in accordance with G.993.5 Annex Q. The data rates for upload are 40 Mbit/s. In upload, the data rates are 40 Mbit/s.

The different levels of Dynamic Spectrum Management (DSM)

VDSL2 vectoring is supported by the Digital Subscriber Line Access Multiplexer( DSLAM) in the local exchange and a VDSL2 vectoring modem at the end user. It is used in FTTC, where fiber optic access technology can be used to supply many subscriber lines. Its implementation is considered to be not entirely unproblematic, since DSL lines from different operators can be located next to each other in subscriber lines, and vectoring involves every single DSL line. However, this would mean that the dynamic spectrum management of the vectoring operator would have to have access to the DSL lines of the competitors.

A further development of VDSL2 and vectoring is supervectoring, which achieves data rates of 300 Mbit/s downstream and 50 Mbit/s upstream.