Ikanos Communications, Inc.

Conexant Systems, Inc.

Brooktree Broadband Holding, Inc.

Julien D Pons

Patrick Duvaut

Massimo Sorbara

Amitkumar Mahadevan

Laurent Alloin

Laurent Pierrugues

Ravindra M Lambi

Oliver Moreno

Murli Mohan Rao

Yue-Peng Zheng

Ehud Langberg

William H Scholtz

Qasem Aldrubi

Hossein Dehghan-Fard

Siva Simanapalli

Karl Yick

Massimo Sobara

Vinod Venkatesan

Arnaud Charton

Laurent Francis Alloin

The present invention relates to methods and apparatuses for managing the time slots in time division duplex (TDD) frames in an xDSL system. According to certain aspects, power savings in a TDD system operating with vectoring may be achieved with sending of quiet symbols in time slots that do not have data and through the efficient configuration of time slots with data and/or idle symbols so as to limit the amount of processing by the vectoring engine within the DO portion of each TDD frame. In embodiments, a central controller in a DPU monitors the data buffers at the transmitter input on each line and computes an optimal configuration of the time slots in the DO portion of the TDD frame to achieve an optimal balance between performance and power dissipation.

Method and apparatus for managing processing in TDD frames to enable power dissipation reduction

According to certain aspects, the present invention improves upon the conventional TCAM scheme by allowing a traditional TCM scheme to be used while in RCM mode. In a RCM mode according to embodiments of the invention, the system uses traditional TCM+SNR margin (i.e. SNRM) with a receiver controlled bit allocation table (BAT) and tone ordering table (TOT). In a TCAM mode according to embodiments of the invention, the system uses uncoded hierarchical modulation similar to the modulation originally proposed for TCAM. According to certain aspects, the transmitter in RCM mode in embodiments of the invention can determine when line conditions require a switch to TCAM mode, and signal the transition to the receiver. Likewise, when in a TCAM mode according to embodiments of the invention, the receiver can request to switch back to RCM via a SRA mechanism, for example.

Method and apparatus for improving performance of transmit controlled adaptive modulation in xDSL and G.fast systems

The present invention is directed to methods and apparatuses for performing concurrent vectoring of systems having communications performed at different symbol rates. In embodiments, where a common binder includes different sub-groups of lines having corresponding different symbol rates, the invention includes methods and apparatuses for managing and concurrently vectoring all the lines of the different sub-groups.

Method and apparatus for performing multi-symbol rate vectoring

A system, method, and a computer readable medium having instructions thereupon for synchronized multi-user multi-carrier communications are provided. For example, a synchronized multi-user multi-carrier communication system includes a transmitter, a receiver communicatively coupled to the transmitter via a plurality of communication channels associated with multiple users, and a computing device, coupled to at least one of the transmitter and the receiver, comprising a memory device in communication with one or more processors. The one or more processors are configured to obtain noise samples for the plurality of communication channels, determine a coupling between carriers on the plurality of communication channels, determine a noise model for a carrier based upon the noise samples and the determined coupling, and store the noise model in the memory device.

System and method for improving spectral efficiency and profiling of crosstalk noise in synchronized multi user multi-carrier communications

A method implemented in a digital subscriber line (DSL) system is described for minimizing a misdetection probability at a far-end coded message receiver during transmission of a coded message. The method comprises jointly determining, at the far-end coded message receiver, a P matrix and a modulation scheme. The method further comprises encoding a message into a coded message with a systematic linear block code, the systematic linear block code having a generator matrix [I P], where I represents a linear block code component identity matrix and P represents the determined P matrix. The method also comprises modulating the encoded message to one or more tones forming a discrete multi-tone (DMT) symbol according to the determined modulation scheme.

Systems and methods for retransmission return channel error detection

Systems and methods for protecting DSL systems against impulse noise are provided. Disclosed herein are example embodiments of a retransmission technique located above the gamma interface (i.e., in the network processing layer). Such a retransmission technique can be combined with standard RS coding with standard erasure-decoding & triangular interleaving at the PMS-TC layer. Example embodiments of the technique involve using the RS code to protect against REIN noise, and using &#x3b3;-layer retransmission for protecting against error events not corrected by the RS code, e.g. a SHINE noise in the presence of REIN. Both techniques are used jointly in the case of combined REIN and SHINE noise.

Systems and methods for protecting DSL systems against impulse noise

A multi-tone transceiver with a components forming a transmit path and a receive path configured to couple via a subscriber line to an opposing multi-tone transceiver for frequency division multiplexed multi-tone modulated communications therewith is disclosed. A noise margin channel identifier is configured to identify within a received tone set, discrete tones each associated with a corresponding one of at least two channels differing from one another in a relative noise margin of associated tones. A Viterbi decoder is responsive to the channel identification provided by the noise margin channel identifier to discretely decode each of the at least two channels; thereby improving the fidelity of the error correction provided by the Viterbi decoder by discretely processing the identified channels within the received set of tones.

Method and apparatus for forward error correction

Included are embodiments for retransmission in a digital subscriber line environment. At least one embodiment of a method includes framing data into transport frames, each transport frame carrying payload data that is viewed differently according to the computing layer in which it is transported; transporting the transport frames over a first computing layer, the payload data of each transport frame corresponding to an integer number Q of elementary cells of the first computing layer, an integer number of header bytes containing information specific to the transport frame, and an integer number of padding bytes; and transporting the transport frames over a second computing layer, the payload data content of each transport frame corresponding to payload data of an integer number M of elementary cells of the second computing layer.

Transport frame structure for retransmission in DSL

Included are embodiments for self protection. At least one embodiment includes Self-protection Unit for protecting a signal that includes a first receiving component configured to receive data, the received data being received as at least one frame and a subframing component configured to subframe at least a portion of the received data, wherein subframing includes converting the at least one into a plurality of subframes. Some embodiments include a subframe interleaver component configured to interleave at least a portion of the subframes.

Self-protection against non-stationary disturbances

A system and method for encoding information is disclosed. In one embodiment, information is encoded using a high protection code for the least significant bit and a low protection code for the next three most significant bits. The remaining bits are uncoded. The high protection code may be a turbo code and the low protection code may be a trellis coded modulation code. In this embodiment, the collection of bits is then mapped according to a diagonally shifted QAM constellation technique.

Hierarchical trellis coded modulation

Embodiments disclosed herein are configured for retransmission above the gamma (&#x3b3;) interface. At least one embodiment of a method includes receiving data from an Ethernet layer, the data being identified as eligible for retransmission or not eligible for retransmission; in response to a determination that the data is eligible for retransmission, storing a copy of at least a portion of the data in a retransmission queue; and transmitting the data across a gamma (&#x3b3;) interface to a packet transfer mode transmission convergence layer.

Retransmission above the gamma interface

Included are embodiments of method for method for computing metrics. At least one embodiment includes searching a MIMO detection tree, the detection tree configuration being formed by a plurality of nodes and a plurality of leaves connected via a plurality of branches, the computational complexity associated with computing a node metric decreases with the node depth in the tree configuration and providing an estimate on a transmitted signal.

Metric computation for lowering complexity of MIMO detection algorithms

Impulse noise from nearby or intense electrical sources can disrupt communications over digital subscriber lines. There are many methods to deal with errors produced by impulse noise sources. Forward error correction (FEC) codes such as Reed Solomon coding along with scrambling and interleaving are used to correct small errors. However, for larger errors, retransmission is favored. Retransmission can be applied at the Discrete Multi-tone symbol level thus eliminating the need to insert sequence identification into data transmission units, furthermore retransmission can also be employed to exploit the error correcting capabilities of the FEC codes. Finally, an impulse noise protection system can exploit impulse noise statistics to configure the redundancy in the FEC codes and to enable the use of blanking. Exemplary embodiments of systems described can cooperatively use impulse noise statistics to utilize retransmission, FEC and blanking to mitigate the effects of impulse noise.

Configurable impulse noise protection system and method based on impulse noise statistics

Various embodiments for mitigating impulse noise are disclosed that cooperatively use impulse noise statistics to utilize retransmission, forward error correction (FEC), and blanking to mitigate the effects of a wide variety of impulse noise sources.

Systems and methods for mitigating impulse noise

In accordance with some embodiments, a communication system is described that comprises a soft-output detector configured to receive a transmit signal and output reliability information regarding the received signal. In accordance with such embodiments, the detector comprises a symbol combiner configured to operate in both a repetition mode and a non-repetition mode, wherein repetition mode comprises receiving a plurality of signals for the transmit signal.

Growing community of inventors

Eatontown, NJ, United States of America

Julien D Pons