Central momdom based on user communications system

Abstract

A method of coordinating very high speed bi-directional data transmissions between a central unit and a plurality of remote units over distinct twisted pair transmission lines that share a binder is described. Specifically, periodic synchronized upstream and downstream communication periods are provided that do not overlap with one another. The upstream and downstream communication periods for allof the wires that share a binder are synchronized. With this arrangement, all of the very high speed transmissions within the same binder are synchronized and time division duplexed such that downstream communications are not transmitted at times that overlap with the transmission of upstream communications. In some embodiments, quiet periods are provided to separate the upstream and downstream communication periods. The described invention may be used in conjunction with a wide variety of modulation schemes, including both multi-carrier and single carrier transmission schemes. It is backwards compatible with existing systems and has particular advantages in very high performance systems.

Description

[0001] This application is a divisional application of a Chinese patent application with an application date of June 19, 1996, an application number of 96195391.8, and a title of "Time Division Multiplexing High Speed ​​Data Transmission System and Method". technical field [0002] This invention relates to very high speed bidirectional digital data transmission systems. In particular, time division multiplexed data transmission schemes suitable for transmission over bundled transmission lines, such as subscriber lines, are disclosed. Background technique [0003] The Alliance for Telecommunications Solutions (ATIS), an organization accredited by the ANSI (American National Standards Institute) standards group, recently finalized a Discrete Multitone-based standard for digital data transmission over Asymmetric Digital Subscriber Line (ADSL). This standard is primarily used to transmit video data over ordinary telephone lines, although it can be used in other applications as ...

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Problems solved by technology

[0008] However, both of the above methods have potential disadvantages

Most notably, in applications with relatively long loops, high frequency signals are significantly attenuated, which makes the transmission more sensitive to noise and prevents the permissible transmission rate, indeed the upstream signal is transmitted at a higher frequency In the system, there is a risk of completely losing the uplink signal, which is not allowed

In asymmetric applications, there is also a greater risk of narrowband noise significantly degrading system performance

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