How does supervectoring 35b work?

Supervectoring 35b enables DSL packages with speeds of up to 300 Mbit/s. But what lies behind this supervectoring and what does the 35b stand for?

A new DSL standard

○35b supervectoring is a further development of the VDSL standard. Alternative terms for it are VDSL Annex Q, Vectoring, and V Plus. The guide article about the DSL connection type includes a chronological list of the most important DSL standards and some general information on supervectoring.

So far these DSL profiles are used: 8a, 8b, 12a, 12b, 17a, 17b and 30a, with 17a the one used most by providers. These designations are defined by the frequency range used (0-8 MHz for the profiles starting with 8, 17 MHz for the one starting with 17, and so on). The fact that this technology is built on existing DSL architecture is a great advantage for network providers. So most of the data transmission can continue on the copper cable network. Only the distribution stations, known as DSLAMs (Digital Subscriber Line Access Multiplexer), need to be updated. From a single DSLAM source, network providers can offer v35 in parallel to ADSL, ADSL+, VDSL2 (for example DTAG 50 Mbit/s) and existing vectoring technology (100/40 Mbit/s). This allows for speeds of up to 300 Mbit/s over a short distance (up to 300 m to the DSLAM).

Download up to 300 Mbit/s

All forms of DSL require participants in a cable bundle to share bandwidth. The more people in a cable bundle who are supposed to receive high data rates at the same time, the less the bandwidth available for each user. A solution is known as ‘vectoring’. It reduces the mutual interference of adjacent copper twin wires within a cable. This procedure requires high processing power from the DSLAMs, since the system has to calculate the interference on every single copper twin wire in a bundle. During the process two signals are sent to the respective twin wire; the actual message signal and a counter signal, which is generated by the calculated interference. This practically eliminates interference signals caused by crosstalk. While this doesn't increase the speed of connections, it does allow a number of fast connections to be in the same cable bundle concurrently. This way a solid 100 Mbit/s can be achieved.

Supervectoring is the next step, using more frequency spectra than ever, to make even greater bandwidths and the latest vectoring technologies possible (300 Mbit/s download, 50 Mbit/s upload).