Mindspeed Technologies, Inc.

Solarflare Communications, Inc.

Marvell International Limited

Interstate Electronics Corporation

Conexant Systems, Inc.

William W Jones

George Zimmerman

Ragnar Hlynur Jonsson

Keith R Jones

Gilberto Isaac Sada Treviño

Sverrir Olafsson

Christopher Pagnanelli

Shrenik P Patravali

Chris Pagnanelli

Gavin D Parnaby

Gilberto Isaac Sada

Maurice M Reintjes

Gilberto Isaac Sada Trevi&ntilde;o

George A Zimmerman

George A Zimmermann

Christopher J Pagnanelli

Apparatus and methods spread input symbols for transmission in multiple dimensions. When input symbols are spread over time, frequency, and code space, the resulting symbols exhibit good immunity to interference. In one embodiment, a system with a multi-tone outer code/modulation and a direct sequence spread spectrum (DSSS) inner code/modulation provides good communications performance characteristics and can be efficiently implemented.

Multi-tone concatenated spread spectrum communications

A system includes converters, first modules, second modules, and a multiplexer. The converters receive an analog signal and a respective one of multiple clock signals. Each of the converters samples the analog signal based on a respective clock signal to generate a respective digital signal. Each of the clock signals is out-of-phase with other ones of the clock signals. The first modules receive the digital signals generated by the converters, remove bias offsets from the digital signals to generate first output signals, and output each of the first output signals on a multiple channels. The second modules receive the first output signals, and based on the first output signals, remove or equalize gain mismatch between the channels to generate second output signals. The multiplexer receives the second output signals, and generates an output based on the second output signals. The output is a digital representation of the analog signal.

Systems with bias offset and gain mismatch removal from parallel transmitted signals

A cancellation system is disclosed for processing incoming and outgoing signals in a transform domain to create a cancellation signal for reducing or removing unwanted interference. Data is ordered based on Good-Thomas indexing into a two dimensional array in a buffer. The two dimensional array may have lrows and lcolumns. From the buffer, the columns of data undergo a Winograd small transform. The rows of data undergo a Cooley-Tukey operation to complete the transform operation into the frequency domain. Multipliers scale the transformed data to generate a cancellation signal in the frequency domain. Inverse (Cooley-Tukey) and Winograd transforms perform inverse processing on the cancellation signal to return the cancellation signal or data to the time domain. Re-ordering the data and combination of the cancellation signal or data with incoming or outgoing signals achieve interference cancellation.

Frequency domain echo and next cancellation

A method and apparatus for compensating for gain offset, bias offset, and skew in a parallel processing environment is disclosed. The method and apparatus may be configured to compensate for mismatches between the sub-channel signals in a parallel ADC. This allows for accurate combination of the signals on the sub-channels. The method and apparatus may be utilized in a high speed data communication system having two or more channels, each of which are interleaved into two or more sub-channels. In one embodiment a DC loop processes signals on two or more sub-channels to account for and remove unwanted bias offset. In one embodiment a sub-channel gain mismatch compensation system (SCGMC) processes signals on two or more sub-channels to account for and remove unwanted gain offset. In one embodiment a skew compensation system, such as a parallel interpolator, processes signals on two or more sub-channels to remove unwanted skew across sub-channels.

Sub-channel distortion mitigation in parallel digital systems

A general-purpose Analog Signal Processing System (ASPS) is disclosed. An ASPS can be realized though an array of Configurable Integrator Blocks (CIBs). The CIBs can be identical to each other, and arranged in rows and columns. A CIB can merge multiplication, integration, and sample-and-hold functions into a single programmable circuit block. Within the ASPS, CIBs are interconnected in a manner that allows CIB inputs to be a combination of external signals and outputs of other CIBs, and allows CIB outputs to be combined to produce system (external) outputs or inputs to other CIBs. This networked architecture combined with the basic functionality of each CIB, enables implementation of a broad range of analog signal processing operations. The ASPS can be field programmable. The field programmability permits end users to be able to quickly and inexpensively fabricate customized analog integrated circuits.

Configurable analog signal processor

A method and apparatus for reducing crosstalk in a multi-channel communication system is disclosed. In one embodiment, outgoing signals in a multi-channel environment are manipulated into a transform domain, such as the frequency domain. Thereafter, the signals may be combined and modified based on a weighting variable to create a cancellation signal. Combined processing greatly reduces system complexity and increases processing speed. After processing in the transform domain, the cancellation signal undergoes further processing to return the cancellation signal into the time domain. The cancellation signal may then be combined with received signals to cancel crosstalk or echo. A method and apparatus for crosstalk cancellation in the analog domain and digital domain is also disclosed. Cancellation at least partially in the analog domain reduces the dynamic range requirements for digital to analog converters within the front-end processing system of a receiver and thereby reducing clipping and increasing operating speed.

Multiple channel interference cancellation

In one embodiment a communication device activation system is provided to restore activation of one or more communication devices that are in a powered-down mode to conserve power usage during a period of inactivity. The activation signal, also referred to as a warm start signal, comprises a sequence signal. A sequence generator generates a desired sequence signal. It is contemplated that one or more sequence signals may be selected for use by the activation system. The sequence signal may be generated or stored and retrieved. To resume communication, a wake-up sequence signal is generated and transmitted to a remote communication device. Upon receipt the received signal is filtered, correlated and analyzed. Analysis may compare one or more aspects of the signal to a threshold signal. If the signal is determined to comprise a wake-up signal, i.e. a request for communication, then a warm-start operation may occur. An acknowledgement signal may optionally be generated to acknowledge receipt of the signal. In one embodiment one or more sequence signals are utilized to monitor channel characteristics and adjust communication device settings accordingly. This may occur as part of the wake-up process.

Communication system activation

A method and apparatus for noise cancellation in a multi-channel communication system is disclosed. In one embodiment this system is configured to cancel FEXT on a victim channel utilizing the signals received on the other channels. The processing benefits gained by a receiver's other filters, such as for example, the FFE and DFE filters, is utilized when generating a FEXT cancellation signal. As a result, the complexity of the apparatus that generates the FEXT cancellation signal may be made less complex since part of the processing burden is performed by other filter apparatus. In one configuration pre-code FEXT cancellation occurs in that a pre-code FEXT filter generates one or more pre-code FEXT cancellation signals corresponding to each of the other channels. The pre-code FEXT cancellation signals are combined, prior to transmission, with the signals associated with each of the other channels, to thereby pre-cancel FEXT prior to transmission.

Method and apparatus for crosstalk mitigation

A method and apparatus for reducing crosstalk in a multi-channel communication system is disclosed. In one embodiment, outgoing signals in a multi-channel environment are manipulated into a transform domain, such as the frequency domain. Thereafter, the signals may be combined and modified based on a weighting variable to create a cancellation signal. Combined processing greatly reduces system complexity and increases processing speed. After processing in the transform domain, the cancellation signal undergoes further processing to return the cancellation signal into the time domain. The cancellation signal may then be combined with received signals to cancel crosstalk or echo. A method and apparatus for crosstalk cancellation in the analog domain and digital domain are also disclosed. Cancellation at least partially in the analog domain reduces the dynamic range requirements for digital to analog converters within the front-end processing system of a receiver and thereby reduces clipping and increases operating speed.

Mixed domain cancellation

A method and apparatus is disclosed to overcome the effects of intersymbol interference during data transmission. Overcoming the effects of intersymbol interference makes possible higher data transmission rates for a given error rate. In one embodiment a receiver processing system a first, second and third filter, such that the second and third filter comprise feedback filters. Filter coefficients are calculated to reduce the undesirable effects of the channel, such as intersymbol interference. A training process occurs to establish the first filter as a mixed phase filter and the third filter as minimum phase filter. The second filter is configured based on the transfer function of the channel and one or more coefficients may be set to a predetermined value.

Method and apparatus for channel equalization

Modem start-up delay reduced by measuring condition of communications line upon connection termination. Variation between termination and start-up line conditions determines if cold or warm start is required. Warm-start may use original condition descriptors. Condition represented by ambient noise, echo or spectral response of channel.

Growing community of inventors

Aliso Viejo, CA, United States of America

William W Jones