Texas Instruments Corporation

3Com Corporation

Yaqi Cheng

Michael Oliver Polley

Song Wu

Adam M Chellali

Walter Y Chen

Tod David Wolf

Ching-Yu Hung

Donald Phillip Shaver

Richard G C Williams

A Joseph Mueller

John R Rosenlof

Dennis G Mannering

Yaser M Ibrahim

Warren L Franz

A multi-line ADSL modem () and network () whereby the multi-line ADSL modem () has connections to several ADSL modems () at a central office (CO) () through a master loop (), shared loops (), and/or broadcast loops (). The master loop () provides the basic connection between the multi-line ADSL modem () and the CO modem () at the central office () while maintaining regular telephone service. The shared loops allow the multi-line ADSL modem to share the transmission capacity with other modems. The multi-line ADSL modem is able to receive broadcast data from the central office where several loops are configured as a broadcast loop for downstream transmission only, but which can also be configured for upstream communication transmission only or in combination with downstream transmission to provide bi-directional broadband communications.

Multi-line ADSL modem

A multi-client ADSL modem network () that can be configured for a home or office network when multiple ADSL client modems () are installed in different communication terminals (). One ADSL modem () at a central office () coordinates the remote multi-client modems () for communication over a single twisted pair loop carrier phone line (), allowing the connected modems () to communicate not only with the CO modem (), but also with each other by sharing frames, tones, or by code division techniques on upstream channels. The CO modem () operates as a network hub and/or arbitrator, and facilitates one ADSL modem to become the master modem and maintain a superframe. The present invention provides home network ADSL service without extra wiring or equipment, thus providing a low cost approach for home networking of ADSL service.

Multi-client ADSL modem

A system and method for providing a local area network utilizing discrete multitone transceivers includes at least two discrete multitone transceivers each of which may be capable of communicating with the central office and with other discrete multitone transceivers in communication with the local area network. The local area network utilizes a set of carriers coordinated between the first discrete multitone transceiver and the second discrete multitone transceiver providing a communication link between the first discrete multitone transceiver and the second discrete multitone transceiver.

System and method for providing a local area network utilizing remote transceivers

A method and apparatus for reducing peak-to-average power ratio in a discrete multi-tone signal. A shaping signal is generated and added to a discrete multi-tone signal to be transmitted. The shaping signal includes tones that are outside a transmission band assigned to the discrete multi-tone signal to be transmitted. One or more filters may be used to suppress the shaping function after digital-to-analog conversion has been performed. Alternatively, echo cancellation may be performed to cancel feedback tones associated with the transmit signal and shaping signal that may occur on the receive path of a discrete multi-tone transceiver. The peak-to-average power ratio reduction method and apparatus may be used in an ADSL modem in one embodiment.

Method and apparatus for reducing peak-to-average power ratio in a discrete multi-tone signal

A decimated and interleaved multiplication table for finite fields as is useful in Reed-Solomon encoding computations. The generator polynomial coefficients determine the multiplication table content and ordering.

Error coding structure and method

A DMT device having an analog front end for receiving an analog signal, a converter for converting the analog signal to a digital signal, a FFT for converting the digital signal from the time domain to the frequency domain and feeding the digital signal to a frequency domain equalizer having variable coefficients for flattening the converted digital signal. The frequency domain equalizer includes a gain corrector coupled to the FFT to compensate the channel frequency rolloff and make each tone approximately the same amplitude before phase rotation and a phase rotator portion responsive to the output of the gain corrector to track small channel variation. Also included is circuitry for updating the coefficients of the frequency domain equalizer, preferably in the form of a slicer for controlling the frequency domain equalizer by feeding back an error signal thereto. The error signal is preferably fed back to the phase rotator portion of the frequency domain equalizer.

MDSL DMT architecture

In a splitterless Digital Subscriber Line (DSL) modem , a receiver architecture ( ) that permits monitoring of harmonics within the upstream channel of a DSL connection. The receiver ( ) can detect the harmonics by monitoring the harmonics in some empty tones or specified tones. A threshold can be set to differ the normal noise power and harmonics power in those empty or specified tones. When a POTS device ( ) coupled to same wire line pair ( ) as the DSL modem ( ) goes off-hook, the DSL modem ( ) can switch from the normal state to an off-hook state in which the harmonics are reduced to minimum by transmitting only the upper sub-band tones of the upstream transmission channel at reduced power levels.

Splitterless modem using harmonics reduction

A splitterless DSL modem (,) with an integrated off-hook detector (,) prevents data loss and/or disconnections as a voiceband device (,) coupled to the same transmission line (,) transition between steady states. The splitterless DSL modem (,) include a DSP (,), an interface (,) to a twisted pair wire line (,), signal converters (,), and various filters (,). The off-hook detector circuit (,) can be coupled to the interface (,) on the analog side of the DSL modem (,) or on the digital side of the signal converters (,).

Splitterless modem with integrated off-hook detector

A programmable logic device (,) as may be used in a communication system device such as a digital subscriber line modem (,) to perform Reed-Solomon decoding upon a received frame of digital values is disclosed. The programmable logic device (,) may be implemented as a DSP (,) or a general purpose microprocessor, for example. According to one disclosed embodiment of the invention, a group of look-up tables (,) are arranged, each look-up table (,) associated with one of the possible power values of a finite field, number up to twice the number of correctable errors. The contents of each entry (SYN) of the look-up tables (,) correspond to the finite field (e.g., Galois field) multiplication of a primitive element raised to an index power with a character of the finite field alphabet. Galois field multiplications (,) in syndrome accumulation may now be performed with a single table look-up operation. According to other disclosed embodiments of the invention, look-up tables (,) are similarly arranged to contain the contents of finite field (e.g., Galois field) multiplication products for use in a Chien search procedure. In a single-thread version of the disclosed Chien search procedure, a subset of the same look-up tables (,) as used in syndrome accumulation may be utilized.

Efficient look-up table methods for Reed-Solomon decoding

A system for digitizing voiceband signals at the remote terminal (,) of a Digital Subscriber Line (DSL) connection and embedding the digitized voiceband component into an active DSL data stream using a DSL modem (,). Voiceband transmissions between the remote terminal (,) and the central office call switching equipment (,) occur in the analog domain when the DSL modem (,) is OFF and in the digital domain when the DSL modem (,) is ON with the digital voiceband signals transmitted over a DSL link. Preferably, the remote terminal (,) can drive a real analog telephone (,) by providing battery feed, ring-trip detection, off-hook detection and ringing generation (,) In-house 4-wire lines pairs (,) are configured between the modem, telephones and computer or home network to permit all digital transmission from the subscriber to the central office.

System and method of transmitting voice over digital subscriber line

A method to estimate the bit loading on each tone of a DMT digital subscriber loop system is disclosed. A generic bit-mapping table is given for different sizes of constellations to save memory space.

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Smyrna, GA, United States of America

Yaqi Cheng