Texas Instruments Corporation

International Business Machines Corporation

Siemens Information & Communication Networks, Inc.

Rolm Systems

Broadcom Corporation

Avago Technologies International Sales Pte. Limited

Siemens Rolin Communication Inc.

Siemens Rdm Communications Inc.

Michael Eugene Locke

Brian Robert Wiese

Daniel T Lai

Claude R Galand

Udayan Dasgupta

Zigang Yang

Jeffrey Mark Blohm

Thomas N Zogakis

Channamallesh G Hiremath

Kapil Gulati

Joseph F Khouri

Channamallesh Hiremath

Kevin Du

Umashanker S Iyer

Richard Glentworth Greenfield

Michael D Agah

Morteza Hagh-Panah

A source node may send a first data unit to a destination node. To send the first data unit, the source node may transmit a modulation pattern over a transmission medium. In some cases, particular data units may correspond to modulation patterns with features that cause errors in transmission. The source node may receive an indication of an error from the destination node. To avoid repeated errors the retransmission, coding circuitry at the source node may alter data within the first data unit to generate a retransmission data unit. The alteration may result in the retransmission data unit corresponding to a modulation pattern different from that of the first data unit. The new modulation pattern may lack the error causing features and reduce the chance of repeated errors.

Data unit retransmission

A method of synchronizing a time division duplex (TDD) multi-line, multi-carrier data communication system is provided. Synchronization is established using unique pseudo-random bit sequences (PRBS) from a common generator polynomial having different seed values. Due to low correlation of PRBS generated with different seed values, a remote unit can only synchronize to its intended signal effectively mitigating far-end and near-end crosstalk impact of large bandwidth very high speed digital subscriber lines (VDSL).

Method of synchronizing a communication system

A method of varying the power output of a transmitter. The method includes providing bit-loading information associated with each tone of multiple tones, where the multiple tones include a first set of tones. The method also includes producing, for transmission, on the first set of tones a first set of constellation symbols based upon the bit-loading information. The method also includes producing a second set of constellation symbols for transmission, where there is a difference of n bits between the bit size of the second bit sequence constellation symbol on each tone of the second set of tones and the bit-loading information associated with each tone of the first set of tones, and where n is an integer greater than or equal to 0.

Variable power communications including rapid switching between coding constellations of various sizes

A method of synchronizing a receiver with a transmitter. The method includes determining number of bits, j, for adjusting a bit stream, where the bit stream is generated from n tones and is dividable into codewords having a codeword length of N bytes, and the number of bits for adjusting the bit stream is determined based upon n and N. The method includes detecting a loss of synchronization indication. In response to detection of the loss of synchronization indication, the method includes adjusting the bit stream by j bits. The method includes determining whether synchronization has been regained. When synchronization has not been regained, the method includes adjusting the bit stream again by j bits. When synchronization has been regained, the method includes terminating adjustment of the bit stream.

Rapid re-synchronization of communication channels

A digital subscriber line (DSL) system that provides fast exit from an idle state includes a central office (CO) modem for communicating with a customer premises equipment (CPE) modem. Prior to entry into a low-power or idle state for the DSL link between the CO modem and the CPE modem, seamless rate adaptation is performed in order to improve the operating margin from that used in full-on operation, for example by selecting a reduced data rate. Transmission parameters, including data rate, and bits and gains, and corresponding to the improved operating margin are stored at the modems. Upon executing short initialization to return from the idle state, the stored transmission parameters are more likely to be adequate to meet current channel conditions, so the exchange of transmission parameters during short initialization is more likely to be avoided.

Optimized short initialization after low power mode for digital subscriber line (DSL) communications

A system and method for reordering tones of a DMT signal within a communication system is described. Cross tone correlated noise in a received signal is identified and rearranged such that tones with correlated noise are spread out throughout the received signal before being processed by a decoder such as, Viterbi decoder. In an embodiment, two tones with the most correlated noise are placed at each end of the sequence of tones presented to the Viterbi decoder. In some embodiment, the tones with correlated noise can be spread such that two adjacent tones with correlated noise have a minimum distance of at least three tones between them at the input to the Viterbi decoder. In other embodiment, tones in the received signal can be processed in various kinds of interleavers for reordering according to the interleaver scheme.

System and method for tone ordering in discrete multi-tone (DMT) modems

A receiver architecture featuring a decimation filter and a bypass around said decimation filter is disclosed along with a method for optimizing said receiver's sampling phase and programmable gain amplifier. Said method utilizes said receiver architecture to modify said receiver's receive path to simplify optimizations.

Communications receiver architectures and algorithms permitting hardware adjustments for optimizing performance

Modem selection of Reed-Solomon codeword configuration to maximize error-corrected data rate given channel analysis. A lookup table of maximal codeword size given parity bytes and channel MSE allows precomputation.

Error-corrected codeword configuration and method

Method for preventing a facsimile server from looping back on itself, the method including the steps of: (a) transmitting fax server identifier information during fax transmission setup; (b) analyzing the fax server identifier information to determine whether the fax server identifier information is the same as that of the fax server that is placing the call; and (c) if the fax server identifier information is the same, dropping the call, otherwise, continuing the call. In a preferred embodiment, the fax identifier information is transmitted in the NSF command of the facsimile communication protocol.

Fax overflow loopback prevention

A system and a method are provided for detecting a type of a received signal. The system includes a processor (32) and two receivers (24, 26). Both receivers (24, 26) are coupled to the processor (32). The first receiver (26) is capable of receiving a first signal type, and the second receiver (24) is capable of receiving a second signal type. An algorithm (30), coupled to the second receiver (24), is used for distinguishing between the first signal type and the second signal type. The algorithm (30) is used after the first receiver (26) begins storing the signal as a first signal type, and after the second receiver (24) begins storing the signal as a second signal type. At least one of the two signal types is retained.

System and method for detecting types of signals in messaging systems

The reliability of call transfer in a PBX can be improved by verifying the availability of a destination port before a transfer is attempted. The incoming call is routed to an alternate line after the interrogation occurs. Once the availability of the desired facility is confirmed, the call can be picked up by the destination port.

Voice/data transfer method and apparatus utilizing an alternate line

By testing a received signal for power, frequency content, and stability, one can measurably improve DTMF signal detection and identification performance in voice store and forward systems. The algorithms described here have been found to be especially useful in minimizing talk-off. Further, the approach improves the performance with acoustic-type generators and minimizes transhybrid loss.

DTMF detection for voice processing equipment

Apparatus for detecting and identifying DTMF signals in connection with a voice store and forward equipment (VSF) and for preventing talk-off, whether generated by the VSF or by a user of the VSF. In particular, the apparatus for use in connection with an interface which receives an analog signal from and applies an analog signal to a telephone line, the apparatus including: (a) detection means, responsive to an analog signal received from the interface, for detecting DTMF signals in the received analog signal and for generating DTMF indication signals in response thereto; (b) means for storing a representation of the received analog signal and at least some of the DTMF indication signals and for applying at least some of the DTMF indication signals to a decision means; and (c) means for retrieving a representation of an output analog signal and a representation of output DTMF indication signals and for applying them to the decision means; wherein the decision means is means for applying the output analog signal to the interface.

DTMF signal detection apparatus

The detection of DTMF tones is improved in a three-step process: first testing even-numbered samples; then testing odd-numbered samples, and finally testing for tone quality (time interval and frequency stability).

Multifrequency detection

A method for dividing a message into a plurality of message blocks and storing each of the plurality of message blocks on separate units within a distributed data storage system. Facilities for retrieving the information from the distributed data storage system and recreating the original message for replay are also provided. If a unit within the distributed data storage system fails, then a degredated version of the original message is recreated from the remaining units and their stored message blocks.

Growing community of inventors

Santa Clara, CA, United States of America

Michael Eugene Locke