Tensorcomm, Incorporated

Rambus Inc.

Iii Holdings 1, LLC

Anand P Narayan

Eric S Olson

John K Thomas

Prashant Jain

Michael Lee McCloud

Tommy Guess

Gagandeep Singh Lamba

Vijay Nagarajan

Louis L Scharf

David Meyer

Greg Graham

Brian Lee Roberts

Kenneth C Grobaski

Eric B Olson

The present invention provides systems and methods for parallel interference suppression. In one embodiment of the invention, a processing engine is used to substantially cancel a plurality of interfering signals within a received signal. The processing engine includes a plurality of matrix generators that are used to generate matrices, each matrix comprising elements of a unique interfering signal selected for cancellation. The processing engine also includes one or more processors that use the matrices to generate cancellation operators. A plurality of applicators applies the cancellation operators to parallel but not necessarily unique input signals to substantially cancel the interfering signals from the input signals. These input signals may include received signals, interference cancelled signals and/or PN codes.

Systems and methods for parallel signal cancellation

A receiver includes a first finger that receives a non-interference-cancelled signal and output first demodulated data, a first phase estimate, and a first PN code. The receiver also includes a second finger that selectively receives the non-interference-cancelled signal and a first interference-cancelled signal generated from the non-interference-cancelled signal based on the first phase estimate and the first PN code. The second finger also outputs second demodulated data.

A receiver employs low-rate processing to synthesize the effect of high-rate interference in a received multi-rate signal. Each high-rate subchannel is analyzed on its low-rate descendents to produce symbol estimates for each low-rate symbol interval. The symbol estimates are applied to low-rate descendent subchannels, which are then combined to synthesize the effects of the high-rate interference. An interference canceller processes the synthesized interference with the received signal for producing an interference-cancelled signal. Alternatively, analogous steps may be applied at high-rate to analyze, synthesize, and cancel the effects of low-rate interference in a multi-rate signal.

Interference cancellation in variable codelength systems for multi-access communication

A receiver in a CDMA system comprises a front end processor that generates a combined signal per source. A symbol estimator processes the combined signal to produce symbol estimates. An S-Matrix Generation module refines these symbol estimates based on the sub channel symbol estimates. An interference canceller is configured for cancelling interference from at least one of the plurality of received signals for producing at least one interference-cancelled signal.

Methods for estimation and interference suppression for signal processing

Methods for estimation and interference cancellation for signal processing

The present invention is directed to the selective provision of interference canceled signal streams to demodulating fingers in a communication receiver. According to the present invention, potential interferer signal paths are identified. Signal streams having one or more potential interferer signals removed or canceled are created, and a correlation is performed to determine whether the strength of a desired signal path increased as a result. If the correlation indicates that the strength of a desired signal path was increased by the signal cancellation, the interference canceled signal stream is provided to the demodulation finger assigned to track the desired signal path. If the correlation determines that the strength of the desired signal path did not increase as a result of performing interference cancellation, the raw or a different interference canceled signal stream is provided to the demodulation finger.

Method and apparatus for selectively applying interference cancellation in spread spectrum systems

A controller for advanced receivers configures a plurality of advanced receiver modules based on figures of merit computed on the input signal. The controller also selects the appropriate output signal based on figures of merit of either the input or the output signals. The controller decisions can also be made in a bursty manner, where only a subset of the decisions to be made are made at a given time, thereby limiting the processing load of the control processor.

Systems and methods for control of advanced receivers

Method and apparatus for interference suppression with efficient matrix inversion in a DS-CDMA system

Systems and methods for serial cancellation

An interference cancelling receiver combines data from multiple paths after aligning to transmitter timing, and uses either an equalizer or a Rake receiver to compute symbol estimates. Interference estimates are generated from the symbol estimates, and multiple interference estimates are combined after re-aligning the interference estimates to receiver timing. At least two segments of symbol estimates are computed for each segment of interference cancelled data. Various techniques may be employed for controlling the latency and sequencing of these operations, and the subsystems within the canceller may use different processing clock speeds.

Methods for managing alignment and latency in interference cancellation

A receiver in a CDMA system comprises a front end processor that generates a combined signal per source. A symbol estimator processes the combined signal to produce symbol estimates. An S-Matrix Generation module refines these symbol estimates based on the subchannel symbol estimates. An interference canceller is configured for cancelling interference from at least one of the plurality of received signals for producing at least one interference-cancelled signal.

The present invention is directed to an efficient method and apparatus for channel determination and interference vector construction in accordance with spread spectrum systems. Channel determination is performed using a first series of fast Walsh transform steps. The results of the first set of fast Walsh transform steps corresponding to valid communication system channels are compared to a threshold value. Results derived from the first set of fast Walsh transform steps are then passed through a second set of fast Walsh transform steps with the number of steps performed for a set of results determined by the symbol length associated with the channels from which the amplitude information was derived. The interference vectors thus obtained for each valid symbol length may then be combined to form a composite interference vector. The fast Walsh transform steps and other steps may be performed using shared hardware components or software modules.

Method and apparatus for channel amplitude estimation and interference vector construction

The present invention provides systems and methods for interference matrix construction. Such an interference matrix may be used to generate a cancellation operator that when applied to a signal may substantially remove selected interfering signals. In one embodiment of the invention, a system comprises an interference selector configured for selecting one or more interferers for interference cancellation. The system also comprises a matrix generator communicatively coupled to the interference selector and configured for receiving selected interferers from the interference selector. The matrix generator is also configured for generating a matrix having one or more vectors, wherein each vector comprises elements of at least one of the selected interferers. Such an interference matrix and the subsequent generation of the cancellation operator may advantageously provide interference cancellation to systems employing CDMA (e.g., such as cdmaOne and cdma2000), WCDMA, Broadband CDMA, UMTS and GPS signals.

Growing community of inventors

Boulder, CO, United States of America

Anand P Narayan