Time-multiplexed transmission on digital-subscriber lines synchronized to existing TCM-
US5991311A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 25, 1997 |
| Grant date | Nov 23, 1999 |
| Priority date | — |
| Expiry date | Oct 25, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q11/0435
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Pulp-insulated telephone cables common in Japan and other countries have higher cross-talk interference than plastic-insulated cables common in the United States. Deployment of newer xDSL systems in Japan has been limited by the high cross-talk interference in those pulp cables, especially the near-end cross-talk (NEXT) from ISDN services using time-compression multiplexing (TCM). A TCM-DSL that can share pulp-cable bundles with TCM ISDN lines eliminates the NEXT interference by synchronizing transmission and reception with the TCM ISDN equipment for the same cable bundle. The TCM-DSL line uses TCM that is synchronized with the ISDN transmit and receive windows so that the TCM-DSL is transmitting but not receiving when the ISDN modems at the same side are transmitting. When ISDN at the same side are receiving and not transmitting, NEXT interference does not exist. Thus higher-speed TCM-DSL data can be received during the ISDN receive windows with reduced interference. A passband modulation technique such as Carrierless-amplitude/phase modulation (CAP) with advanced signal processing techniques such as trellis encoding and pre-coding achieve higher data rates for TCM-DSL. The TCM-DS…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.