US 5,809,033 A · Use of modified line encoding and low signal-to-noise ratio based signal processing to extend range of digital data transmission over repeaterless two-wire telephone link

Abstract

The range of digital data communication services, such as a basic rate 2B1Q ISDN channel, to customer premises located beyond the industry standard achievable range of a two-wire loop can be extended by increasing the capacity of the ISDN line code from two information bits per symbol to three information bits per symbol, so as to reduce the effective symbol rate, which is error correction encoded to an effective 4B1H line code for defining a sixteen level PAM signal waveform, and employing enhanced low signal-to-noise ratio signal processing techniques in both the transmitter and receiver to accommodate the increased insertion loss of the two-wire line resulting from its extended length. Such enhanced low signal-to-noise ratio signal processing techniques include a Tomlinson precoder in the transmitter, and an adaptive linear equalizer and a module unit in the receiver.

Claims62

Dependent claims

A method for extending the distance for delivering digital communication signals to be transported over a transmission path between a first site and a second site, comprising the steps of:

(a) converting first digital communication signals, having a data rate and encoded at a first symbol rate as a first line code containing a first number of information bits per symbol, into second digital communication signals having said data rate and encoded at a second symbol rate different from said first symbol rate as a second line code containing a second number of information bits per symbol different from said first number of information bits per symbol of said first line code;
and
(b) processing said second digital communication signals for delivery over said transmission path to said second site.

A method for delivering basic rate integrated services digital network (ISDN) connectivity from a central office site to a remote site, comprising the steps of:

(a) receiving ISDN signals having a data rate from a central office communication device for delivery from said central office site to said remote site;
(b) processing said ISDN signals received in step (a) into non-basic rate formatted and modulated ISDN signals, having said data rate and a changed symbol rate corresponding to a number of information bits per symbol different from a number of bits per symbol of basic rate formatted and modulated ISDN signals, that provide extended range delivery at said changed symbol rate and said data rate over a single pair of wires from said central office site to said remote site;
(c) at said remote site, receiving said non-basic rate formatted and modulated ISDN signals that have been delivered over said single pair of wires at said data rate and said changed symbol rate from said central office site, and recovering information contained therein;
and
(d) forwarding said information recovered in step (c) to a customer site served by said remote site, using basic rate formatted and modulated ISDN signals.

2 more elements

Dependencies are inferred from the claim text.

Use of modified line encoding and low signal-to-noise ratio based signal processing to extend range of digital data transmission over repeaterless two-wire telephone link

Life of this patent

Use of modified line encoding and low signal-to-noise ratio based signal processing to extend range of digital data transmission over repeaterless two-wire telephone link

Life of this patent

Abstract

Claims62