Brooktree Broadband Holding, Inc.

Globespan Virata Corporation

Globespan, Inc.

Globespan Technologies, Inc.

Ikanos Communications, Inc.

Conexant, Inc.

Globespan Semiconductor, Inc.

Conexant Systems, Inc.

William H Scholtz

Ehud Langberg

Shareq Rahman

Patrick Duvaut

Lujing Cai

Daniel Amrany

Xy Chen

James Zhang

Ben Chan

Laurent Pierrugues

Richard Gut

Oliver Moreno

Massimo Sorbara

Arnold Muralt

Julien D Pons

Marc R Delvaux

Albert Rapaport

Weimin Liu

Yan Wu

Feng Ouyang

Farooq Jabbar

Xiao Liu

Laurent Hendrichs

Xian-Ying Chen

A method and system are provided for preventing data loss in a VoIP system. In particular, during a VoIP call, it is determined whether incoming ringing on a POTS line causes an unacceptable level of signal loss or errors. If so, for subsequent VoIP calls, the CO handling calls to the POTS line is instructed to either answer each call with a busy signal or automatically forward calls to the POTS line to the VoIP line or other selected telephone. Calling returns to normal upon ending of the VoIP call. In this manner, incoming ringing on the POTS line does not result in call dropping or lengthy retraining processes.

Residential gateway for voice over internet protocol communications

Method and system for preventing data loss in a real-time computer system

Systems and methods for performing bit loading in a dual latency data transmission system. In a computer network, such as an XDSL-based network, carrier channels are allocated between two latency paths. Error sensitive information is transmitted over a latency path employing one or more forward error correction techniques. Latency sensitive information that is relatively more tolerant of errors is transmitted over the other latency path. Rather than employing the lowest coding gain for carrier channels having the two different latency paths, the highest coding gain for each path is used by applying different target S-N-R margins for carrier channels having different latency paths.

Systems and methods for improved bit loading for discrete multi-tone modulated multiple latency applications

A technique for improving multiple-channel multi-tone transmissions is disclosed. According to one particular embodiment, a method for transmitting data over at least two bonded channels is provided, wherein each of the at least two bonded channels comprises a plurality of tones. The method may comprise: transmitting a first symbol stream over a first tone in a first bonded channel and over a second tone in a second bonded channel, wherein the first tone is bonded to the second tone, and the transmissions over the first tone and the second tone are substantially in parallel; transmitting a second symbol stream over a third tone in the first bonded channel; and transmitting a third symbol stream over a fourth tone in the second bonded channel, wherein the third tone is bonded to the fourth tone, and the transmissions of the second symbol stream and the third symbol stream are substantially in parallel.

Technique for improving multiple-channel multi-tone transmissions

Disclosed herein are various techniques for multilevel channel coding. For a given binary word comprising a plurality of bits, the least-significant bit may be encoded by a boosted coding technique, such as turbo channel coding or low density parity check (LDPC) channel coding. A subset of the remaining bits of the binary word may be encoded using trellis coded modulation (TCM) coding. The results of the boosted channel coding and the TCM coding may be mapped to one or more symbols. The one or more symbols then may be transmitted to a receiver using transmission techniques well known to those skilled in the art. The present invention finds particular benefit in digital subscriber line (DSL)-based systems in accord with the ITU G.922.1 Recommendation and similar standards.

Multilevel channel coding in ADSL

Various embodiments for addressing the performance objectives of LDSL and examples of smart systems for LDSL are disclosed. An evaluation of the spectral compatibility of two LDSL modes based on two different downstream masks, identified herein as LDSL Wide and Narrow, is disclosed. Spectral compatibility is evaluated in accordance with existing rules. Other embodiments may further comprise determining features of upstream transmission.

Implementation of smart DSL for LDSL systems

A system and method for multiple inputs, multiple outputs (MIMO) PSD allocation in a DSL system is disclosed. In some embodiments, the method may comprise monitoring system performance by performing a multi-ended line test (MELT), processing the MELT and allocating PSD based on at least one of system coupling power and system traffic.

MIMO dynamic PSD allocation for DSL networks

An improved ADSL modem is presented. The ADSL modem in cooperation with a remote ADSL modem will exchange manufacturer identification information during initial DSL system training to establish a DSL communication link. The improved ADSL modem may comprise a memory device containing system parameters and operational algorithms previously determined to maximize DSL link performance between ADSL modems manufactured by different vendors. The improved ADSL modem is well suited for central office applications as it provides a solution for optimizing system performance that is transparent to remotely located ADSL modems. An ADSL modem in accordance with the present invention may comprise a digital signal processor and a memory device configured to store appropriate system parameters and operational algorithms that provide an optimized DSL communication link once applied during system initialization. The present invention also provides a method for optimizing DSL system performance. The method can be described by the following steps: supplying a default manufacturer identification for a remote modem at a master modem; applying appropriate system parameters and algorithms in response to the default manufacturer identification; initializing DSL system start-up training; receiving the actual manufacturer identification for the remote modem; determining if the current system parameters and algorithms are suitable for a DSL link with the actual manufacturer; adjusting training parameters and algorithms; restarting training when required; and establishing the DSL link.

System and method for optimizing digital subscriber line performance between transceivers from multiple manufacturers

The present invention provides a system and method for reducing power consumption by shaping the spectrum of a downstream signal. Incremental improvements in power consumption due to spectral shaping produces a noticeable reduction in the aggregate power consumed at a central office in asymmetric digital subscriber line (ADSL) systems.

System and method for reducing power consumption by spectral shaping of signals

Systems and methods for increasing data capacity in communication systems is presented. In one embodiment, line characteristics are determined, and a downstream bandwidth is adaptively allocated in response to the determined line characteristics. In this regard, the upstream and downstream bandwidths may be seen as adaptively changing as a function of line characteristics.

System and method for increasing data capacity in communication systems

The present invention is directed to a system and method that detects periods of no activity in the downstream data path of a DSL modem and reduces the transmit power in the output line driver to reduce power consumption in the modem. A preferred method is operative at the central office DSL modem and comprises detecting periods of no activity in the downstream data bins, reducing the transmit power in response to the inactivity on the communication link, detecting either upstream or downstream data, and performing a fast retrain of the modem to restore nominal power data transmission in the downstream direction. A variation of the preferred method uses a reduced point constellation encoding scheme to reduce power consumption. Broadly, the system of the present invention may be realized by a configurable transmit channel line driver and a digital signal processor.

System and method for reduced power consumption in digital subscriber line modems

A system and method for performing peak-to-average power ratio reduction in a transmitter using pulse amplitude modulation (PAM) encoding. Broadly, a transmitter is configured to perform active digital filtering to detect encoded data symbols that if uncorrected would lead to relatively high analog signal peaks in the data transmission. A prediction is made of the peak values that would be applied at the digital to analog converter (DAC) if the original output of the Tomlinson precoder was sent into the shaping filter. If the absolute value of the predicted peak value exceeds a threshold, a correction of a full 2L step is applied for one sample of the Tomlinson precoded stream. The correction step is applied in such a way as to reduce the resulting peak output. Two methods of predicting the peak values are presented. The first method segments the shaping filter into causal and non causal portions so that no extra delay is introduced. The second method uses a two-stage approach where a first pass provides symbols without correction, then corrected symbols are injected in a duplicate modulation filter (this implies an extra delay equal to the filter delay). A variation of the two-stage approach takes advantage of the linear aspects of the Tomlinson preceding.

System and method for peak to average power ratio reduction

A system and method are disclosed for synchronizing a predetermined repeated data sequence contained in a first data signal at a first sample rate with the same predetermined repeated data sequence contained in a second data signal at a second sample rate in a data communications device. The system preferably includes a digital signal processor operating pursuant to logic stored on a memory. The logic includes synchronization logic which reduces the first sample rate to a predetermined correlation sample rate using a first decimator, resulting in a first reduced data signal. The synchronization logic also reduces the second sample rate to the same predetermined correlation sample rate using a second decimator, resulting in a second reduced data signal. Finally, the synchronization logic determines a sequence offset between the predetermined repeated data sequence contained in the first reduced data signal and the predetermined repeated data sequence contained in the second reduced data signal using a correlator. This sequence offset is used to determine a time delay that is applied to the second data signal, thereby synchronizing the predetermined repeated data sequence contained in the first and second data sequences.

Growing community of inventors

Middletown, NJ, United States of America

William H Scholtz