2 Digital subscriber line VDSL2
2.11 Frequency plans for asymmetrical data transfers

Data transmission with asymmetric transfer rates are anticipated rather to domestic subscribers, where the transfer rate is in the downstream direction substantially higher than the transmission speed in the opposite direction.

However, with regard to the number of sub bands for the upstream direction, should VDSL2 connection in asymmetric transfer mode to achieve higher transmission rate than that of older ADSL connection.

Basic frequency plan 998 is further divided into:

- 998 - fundamental frequency plan with the usual alternating bands for the downstream and upstream taken from the first generation VDSL connections,
- 998E - frequency plan with the usual alternating bands for the downstream and upstream extended to 17 MHz, respectively up to 30 MHz,
- 998ADE - frequency plan designed for data transfer with significantly asymmetric speeds.

Example of 998ADE frequency plan parameters for each profile VDSL2 connections in Europe.
VDSL2 profile | The highest utilized subchannel | Upper limit frequency for downstream [MHz] | Upper limit frequency for upstream [MHz]
8a | 1971 | 8,5 | 5,2
8b | 1971 | 8,5 | 5,2
8c | 1971 | 8,5 | 5,2
8d | 1971 | 8,5 | 5,2
12a | 1971 | 8,5 | 12
12b | 1971 | 8,5 | 12
17a | 4095 | 17,664 | 12
30a | 2479 | 24890 | 30

Substitution each band in frequency plans for asymmetrical data transfers.