Multiplex communications – Generalized orthogonal or special mathematical techniques – Fourier transform
Reexamination Certificate
1998-12-31
2001-07-17
Nguyen, Chau (Department: 2663)
Multiplex communications
Generalized orthogonal or special mathematical techniques
Fourier transform
C370S359000, C375S260000
Reexamination Certificate
active
06262972
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to digital communication trunks. More specifically, the present invention relates to a system and apparatus for increasing the effective communication bandwidth through such trunks.
BACKGROUND OF THE INVENTION
Several factors, including the wide adoption of the Internet and the convergence of various communication media have lead to a phenomenal growth in the amount communications bandwidth that is required in the world. While much effort is being expended at establishing new networks to provide the needed bandwidth, the cost of constructing such networks can be very high. Further, right of ways, cable paths or other physical requirements may not be readily available for deploying such new networks in some locations. Also, the costs of earlier, lower bandwidth networks may not yet have been fully recouped and a telecommunications carrier may thus have a strong economic disincentive to commence construction of a new network.
It is therefore desired to have a system and apparatus which can work with at least some part of an existing networking infrastructure but which can provide an increased effective bandwidth through the network.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a novel system and apparatus for providing an increase in effective bandwidth in a digital communication trunk.
According to a first aspect of the present invention, there is provided a digital communication trunk for transmitting digital data between two distal central offices each connected to a network segment by a digital discrete multitone end unit, comprising:
a digital interface to receive baseband digital information to be transmitted through said network segment;
a digital discrete multitone transmitter to receive said baseband digital information and to convert said baseband digital information into digital multitone information;
digital discrete multitone code to convert said digital multitone information into encoded analog information in a plurality of frequency bands;
a transmit line driver to convert said encoded analog information to predefined signal transmission levels for transmission on said network segment;
a receive line driver to amplify tone information received from said network segment to a predefined signal level;
a digital discrete multitone code to convert said encoded analog information from said receive line driver into digital multitone information; and
a digital discrete multitone receiver to receive said digital multitone information and to form baseband digital information therefrom, said digital interface outputting said formed baseband digital information.
The present invention also provides, where two or more network segments of a digital trunk are employed to connect the central offices, a digital discrete multitone repeater unit to connect the network segments. The digital discrete multitone repeater unit includes a pair of repeater functions, each repeater function comprising:
a receive line driver to amplify encoded analog information received from a network segment to a predefined signal level;
a digital discrete multitone code to convert said encoded analog information to digital multitone information;
a digital discrete multitone receiver to receive said digital multitone information and to form baseband digital information therefrom;
a digital discrete multitone transmitter to receive said baseband digital information and to convert said baseband digital information into digital multitone information;
a digital discrete multitone codec to convert said digital multitone information into analog tone information; and
a transmit line driver to convert said analog tone information to a predefined signal transmission level for transmission on another network segment.
The present invention allows telecommunication carriers to increase the effective bandwidth of existing digital communication trunk lines, such as T1 or E1 trunks, by replacing the repeaters in such trunks with digital discrete multitone repeaters and by providing each central office with a digital discrete multitone end unit. In one embodiment of the invention, the effective bandwidth of an existing T1 trunk can be increased fourfold, to T2 transmission rates, allowing T2 transmissions or four mutliplexed T1 transmissions to be achieved without requiring the replacement of T1 standard copper twisted pair infrastructure.
REFERENCES:
patent: 6137839 (2000-10-01), Mannering et al.
patent: 6144659 (2000-11-01), Nye et al.
Warrier, Padmanand. “DSP Solutions for Voiceband and ADSL Modems,” Application Report SPAA005. World Wide Broadband Access Group, Texas Instruments, Jun. 1998.
McGinn John D.
Ozkan Oguz
Wong Paul K.
Nguyen Chau
Northern Telecom Limited
Trinh D.
Zavis Katten Muchin
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