Broadcom Corporation

International Business Machines Corporation

Gottfried Ungerboeck

Thomas J Kolze

Bruce Joseph Currivan

Nabil R Yousef

Scott R Powell

Ba-Zhong Shen

Daniel Harvey Howard

Pierre R Chevillat

Arthur J Carlson

Francois Bernard Dolivo

Dietrich G Maiwald

Oscar Ernesto Agazzi

Giovanni Cherubini

Pieter Vorenkamp

Sedat Oelcer

Kevin Tunghai Chan

Alain R Blanc

Keshab K Parhi

Myles H Wakayama

Lin He

Christian Lutkemeyer

Thomas D Howell

Jeyhan Karaoguz

Kelly Brian Cameron

Malcolm Scott Ware

Hau Thien Tran

Kevin Brown

Jean-Claude Abbiate

Jack T Murray

Sylvie Gohl-Roux

Istvan Peter Csajka

Hans P Kaeser

Ba-Zong Shen

A method, system and computer program product to adjust transfer rates on conductors in a multi-conductor cable comprising monitoring signals received on each conductor, determining a Signal to Noise Ratio (SNR) for each conductor and adjusting a transfer rate on one or more conductors based on the corresponding SNR. In an embodiment the multi-conductor cable is a twisted pair Ethernet cable. The method further comprises determining whether a conductor is transmitting at an optimal transfer rate as a function of its SNR, calculating an optimal transfer rate for each conductor as a function of its SNR and periodically measuring a change in SNR on each conductor. If the change in SNR is greater than a predetermined threshold, then the transfer rate is re-calculated for the conductors requiring transfer rate adjustment as a function of SNR.

Dynamic adjustment of transfer characteristics as a function of channel characteristics

Signal processing under attenuated transmission conditions. Within an orthogonal signal space, the number of orthogonal signals that are used to transmit information from a transmitter to a receiver is reduced and the transmitted power of each of the now remaining orthogonal signals is modified; this may involve increasing the power of all of the remaining orthogonal signals equally or alternatively modifying them individually. The same modulation used before the reduction may also be used afterwards; within communication systems having multiple transmitter-receiver paths, this will ensure that the communication system's throughput and efficiency will remain unchanged even when one (or more) transmitter-receiver paths are highly attenuated. In addition, robust mode operation is provided for ranging and registering of transmitter devices when entering the communication system. In addition, the unused orthogonal signals may be employed to support interference cancellation of those orthogonal signals that are used to transmit information.

Signal processing under attenuated transmission conditions

Certain aspects for the start-up procedure of transceivers supporting higher data rates over twisted-pair copper cabling are provided for 10 Gbit/sec Ethernet links (10GBASE-T). During a PMA (physical medium attachment) training period of the start-up procedure, long PMA training frames are exchanged periodically between link partners. A significant portion of each PMA training frame consists of known pseudo random sequences simultaneously transmitted over four wire pairs. PMA training frames include an InfoField for exchanging parameters and control information between link partners. For example, the InfoField's payload comprises fields for indicating current transmit power backoff (PBO), next PBO, requested PBO, transition count, control information, and for communicating precoder coefficients. Information in InfoFields is repeated and is not necessary that a link partner decodes every InfoField. For example, by occasionally reading the transition count, a link partner can determine when a change in transmit PBO and/or a state transition is to occur.

Method and system for 10GBASE-T start-up

A method and apparatus is disclosed to map a sequence of data to Quadrature Amplitude Modulation (QAM) constellation symbols. The method and apparatus encodes only a portion of the sequence of data and leaves a remaining portion of the sequence of data unencoded. The encoded portion of the sequence of data and the remaining unencoded portion of the sequence of data are then mapped into modulation symbols of the QAM constellation. The encoded portion of the sequence of data selects subsets of the QAM constellation, and the remaining unencoded portion of the sequence of data determines a specific modulation symbol within each subset of the QAM constellation.

Low density parity check (LDPC) encoded higher order modulation

Various systems and methods related to equalization precoding in a communications channel are disclosed. In one implementation precoding is performed on signals transmitted over an optical channel. In one implementation precoding and decoding operations are performed in parallel to facilitate high speed processing in relatively low cost circuits. Initialization of the precoders may be realized by transmitting information related to the characteristics of the channel between transceiver pairs.

System and method for high speed communications using digital signal processing

A communication system performs burst noise cancellation. A transmitter produces and transmits a spread signal that comprises at least one known-value symbol spread by a plurality of non data-carrying orthogonal codes and data symbols spread by at least one data-carrying orthogonal code. The transmitter transmits the spread signal across a communication link that introduces burst noise. A burst noise detector determines burst noise affected chips of the orthogonal codes. A weight computation functional block calculates a plurality of complex-valued combining weights based upon the burst noise affected chips. A vector de-spreader and a linear combiner operate in combination to use the plurality of non data-carrying orthogonal codes, the at least one data-carrying orthogonal code, and the plurality of complex-valued combining weights to de-spread the received spread signal to produce the data symbols with the burst noise substantially removed.

Cancellation of burst noise in a communication system with application to S-CDMA

A two-stage block synchronization and scrambling module includes a synchronization PRNG module, a scramble PRNG module, a summing module, and a storage module. The synchronization PRNG module is clocked once per N+1 bit PCS frame (N arbitrary) to produce a synchronization bit and a pseudo-random starting state for the scramble PRNG. The scramble PRNG module is clocked N times per PCS frame to produce a cipher stream starting with a pseudo-random state from the synchronization PRNG. The summing module is operably coupled to sum the cipher stream and a PCS frame payload to produce scrambled payload. The storage module is operably coupled to store the scrambled payload with the synchronization bit. Synchronization bits from successive frames are a running bit-serial representation of the synchronization PRNG state and are used by the receiver to synchronize with the transmit scrambler.

Two-stage block synchronization and scrambling

A method for modulating a sequence of data symbols such that the transmit signal exhibits spectral redundancy. Null symbols are inserted in the sequence of data symbols such that a specified pattern of K data symbols and N&#x2212;K null symbols is formed in every period of N symbols in the modulated sequence, N and K being positive integers and K being smaller than N.

Subdimensional single-carrier modulation

In a communication system, Huffman coding techniques are used to obtain shaping gains for an improvement in data transmission rates. More particularly, a novel method of Huffman shaping is described that achieves a shaping gain of greater than 1 dB. The shaping gain results in a higher data rate transmission in a communication system where transmitted power is constrained.

System and method for Huffman shaping in a data communication system

Various systems and methods related to equalization precoding in a communications channel are disclosed. In one implementation preceding is performed on signals transmitted over an optical channel. In one implementation preceding and decoding operations are performed in parallel to facilitate high speed processing in relatively low cost circuits. Initialization of the precoders may be realized by transmitting information related to the characteristics of the channel between transceiver pairs.

Growing community of inventors

Langnau a.A., Switzerland

Gottfried Ungerboeck