Motorola Corporation

Terence L Johnson

Michael R May

Matthew A Pendleton

Peter R Molnar

Howard E Levin

Mathew A Rybicki

Jeffrey P Gleason

Carlos A Greaves

Albert H Higashi

Sujit Sudhaman

Jody H Everett

John M Porter

Robin Wiprud

Jean-Louis Dolmeta

In the present invention, an ADSL system (,) identifies good bin as a bin capable of successfully transmitting data to a destination. A bad bin is identified as a carrier that is not capable of successfully transmitting data to the destination. A marginal bin is identified as a carrier that may be capable of transmitting data to the destination. The power to a bad bin is reduced and allocated to the marginal or good bin(s) to allow an increased bit rate. In another embodiment, the power to marginal bin is reduced and allocated to the good bin(s).

Method for allocating data and power in a discrete, multi-tone communication system

An equalizer (106, 146) for use in systems such as an asymmetric digital subscriber line (ADSL) transceiver (5) reduces the number of calculations required for updating the equalizer coefficients. The equalizer (106, 146) takes advantage of the substantially symmetrical phase and amplitude distortion of the signal constellation, which causes both the amplitude and the phase relationship of the calculated error term for each constellation point to be equal. Instead of performing a full complex multiplication, the equalizer (106, 146) uses some but not all of the product terms between the real and imaginary components of the calculated error term and the conjugate of the received data estimate in the coefficient update calculation. The result is then scaled to account for the missing terms. The resulting equalizer (106, 146) requires fewer calculations for coefficient updating.

Method and apparatus for equallization in an asymmetric digital

A communications system 10 having an Asymmetric Digital Subscriber Line (ADSL) transceiver (24) is provided which may be configured either as a central office or a remote terminal in a system. The transceiver (24) operates in a listen/report idle state to report line activity to a host processor (22) prior to being configured as a central office or remote terminal. The host processor configures the transceiver (24) as a central office, remote terminal, or as otherwise specified based on the line activity.

Apparatus and method for auto-configuring a communication system

A transceiver (5) for an asymmetric communication system such as asymmetric digital subscriber line (ADSL) includes a configuration register (71) defining operation at either a central office (CO) or a remote terminal (RT). The configuration register (71) includes a control bit (72) for selecting either CO or RT mode. The transceiver (5) includes a signal processing module (70) configured according to the state of the control bit (72). For example, a digital interface (70) converts transmit data into transmit symbols and converts received symbols into receive data. The digital interface (70) uses a large memory (158) as a buffer in the transmit path and a small memory (160) as a buffer in the receive path in CO mode. In RT mode, the digital interface (70) uses the small memory (160) in the transmit path and the large memory (158) in the receive path. The selective configuration allows a single integrated circuit to be used in both CO and RT equipment.

Single-chip software configurable transceiver for asymmetric

A host processor (22) in a communication system (10) identifies a level of program visibility for reporting predetermined activation state changes, and signals a communications transceiver (24) to begin an initialization process. The communications transceiver (24) begins executing a series of states (51-55, 61-64) for initializing the communication system (10). A determination is made by the transceiver (24) whether a state change has occurred. A state change is identified and reported to a host processor (22) based on the program visibility select level.

Transceiver and method for reporting state transitions in a

A symbol generator (804) generates a time-domain discrete multi-tone symbol (810). A magnitude comparator (812) compares the magnitude of the time-domain discrete multi-tone symbol (810) with a magnitude threshold. When the magnitude of the time-domain discrete multi-tone symbol (810) compares unfavorably to the magnitude threshold, a magnitude adjusting symbol (816) is added to the time-domain discrete multi-tone symbol (810) such that the magnitude of the time-domain discrete multi-tone symbol (810) is reduced, thereby reducing the peak-to-average requirements (PAR).

Method and apparatus for reducing peak-to-average requirements in

A flexible asymmetrical digital subscriber line (ADSL) transmitter is able to operate simultaneously with integrated services digital network (ISDN) terminal equipment (TE) using a common telephone line (18). The ADSL transmitter changes the frequency content of a frequency-encoded ADSL signal (104) so that its frequency content does not overlap the frequency content of the ISDN TE signal. A corresponding ADSL receiver located within a central office (CO) adapts to the changed frequency content, allowing the ADSL signal to be transmitted over the telephone line without substantial loss of signal integrity. In one embodiment, an ADSL transmitter (100) converts ADSL symbols making up the frequency-encoded ADSL signal (104) into a corresponding time domain signal. The transmitter (100) then interpolates the time domain signal and high pass filters the interpolated signal. This high pass filtered signal is then converted to analog form, bandpass filtered, and driven onto the telephone line (18).

Flexible asymmetrical digital subscriber line ADSL transmitter, remote

An ADSL receiver (200) receives an upstream modified ADSL signal and an ISDN signal from a remote terminal (32) on a twisted-pair copper wire (18). An ADSL transmitter (100) of the remote terminal (32) transmits the ADSL signal in a frequency range above an ISDN frequency range so that the ADSL signal does not overlap the frequency range of the ISDN signal. In one embodiment, the ADSL receiver (200) includes a band pass filter (201), an analog-to-digital converter (203), a decimator (205), a fast Fourier transform (210), and a digital signal processor (212). The decimator (205) converts the ADSL signal back to base band, thus allowing an ADSL signal source to simultaneously utilize the telephone line with an ISDN signal source, without significantly reducing ADSL throughput.

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Austin, TX, United States of America

Terence L Johnson