University of Minnesota

Samsung Electronics Co., Ltd.

Dsp Group Limited

Regents of University of Mn

Jaekyun Moon

Jihoon Park

Younggyun Kim

Jun Young Lee

Barrett J Brickner

Jun Yeop Lee

Michael E Butenhoff

Paul C Edwards

Jaewook Lee

Travis Roger Oenning

Bernardo Rub

Hui Jin

Farshid R Rad

Barret J Brickner

An electronic MIMO-OFDM carrier frequency recovery method is disclosed. The method includes receiving a wirelessly propagated time-domain signal observation, estimating a data-channel vector from a latest observation vector by correcting for a phase rotation effect based on an initial estimate or an up-to-date estimate of a phase rotation term, removing an effect associated with the data-channel vector from the latest observation vector using the estimated data-channel vector to obtain an up-to-date estimate of the phase rotation term; and repeating those prior acts iteratively to allow for production of FFT input samples that are free or nearly free of carrier frequency and phase error.

High-bandwidth over-the-air signal processing

In general, the disclosure describes techniques for detecting and correcting single or multiple occurrences of data error patterns. This disclosure discusses the generation and application of high-rate error-pattern-correcting codes to correct single instances of targeted error patterns in codewords, and to further correct a significant portion of multiple instances of targeted error patterns, with the least redundancy. In accordance with the techniques, a lowest-degree generator polynomial may be constructed that targets a set of dominant error patterns that make up a very large percentage of all observed occurrences of errors. The lowest-degree generator polynomial produces distinct, non-overlapping syndrome sets for the target error patterns. The lowest-degree generator polynomial may be constructed such that no two error patterns within the list of dominant error patterns map to the same syndrome set, and the single occurrence and starting position of any of the target error patterns can be successfully identified.

Error detection and correction using error pattern correcting codes

In a method of detecting an error pattern in a codeword transmitted across a noisy communication channel, a codeword is detected. A syndrome is then generated by applying a generator polynomial to the codeword. The generator polynomial is adapted to produce a distinct syndrome set for each of 'L' (L&#x3e;1) different error patterns potentially introduced in the codeword during transmission across the communication channel. A type of an error pattern within the codeword is detected based on the syndrome or a shifted version of the syndrome, and then a start position of the error pattern within the codeword.

Error correction method and apparatus for predetermined error patterns

A method of constructing an effective generator polynomial for error correction by which a unique set of syndromes for each error event is produced is provided. The method includes preparing a set of dominant error events from the intersymbol interference characteristics of media; and generating a codeword from the data using a non-primitive generator polynomial that produces a unique syndrome set which completely specifies each dominant error event.

Method of detecting and correcting a prescribed set of error events based on error detecting code

An estimated current phase error is used to control the oscillation frequency of a voltage controlled oscillator used to control the timing of sampling operations performed by an analog to digital converter (ADC). The current phase error is calculated by a recursive computation using a previous phase error in order to eliminate noise effects from the current phase error.

Method and apparatus for controlling sampling of signals produced in relation to stored data

In an error correction method, a codeword is transmitted through a noisy communication channel and detected by a receiving device. An error detection code is then applied to the detected codeword to generate a syndrome. Where the syndrome is not all zero, the codeword is determined to contain some error. Accordingly, the method computes a set of potential error start positions for a plurality of error events based on a syndrome value corresponding to the syndrome. Next, a confidence value is computed for each of the plurality of error events at each of the potential error start positions in the refined set, and finally, a most likely error event in the detected codeword is corrected based on an error event and corresponding potential error start position having the highest confidence value.

Post-viterbi error correction method and apparatus

Apparatuses and methods for detecting error events in a codeword reproduced by perpendicular magnetic recording medium (PMR. The method includes: generating cyclic redundancy check (CRC) parity bits based on a generator polynomial for a source information sequence to be recorded on PMR medium and recording a codeword in which the generated CRC parity bits are added to the source information sequence; and reading the recorded codeword and an error event in the read codeword. It is possible to detect error events when a codeword recorded by PMR is read, using a small number of bits.

Method of detecting error event in codeword reproduced by perpendicular magnetic recording medium and apparatus using the same

Digital communication signals that encode information in the phase may be susceptible to phase error from many sources. A device corrects for carrier and sampling phase errors, as well as additive phase noise. A digital phase locked loop simultaneously tracks the carrier phase error and the sampling phase error, and corrects the signal in the frequency domain. The device may use the sampling phase error to advance or delay the sampling window used to convert the signal from the time domain to the frequency domain.

Digital phase locked loop

A method of analyzing soft symbol information in a communication system that transmits multiple independent data streams is disclosed. The method includes setting a trellis structure using a fixed spatial delay constraint, calculating a joint probability between a targeted symbol and a set of observation samples either recursively or nonrecursively, and approximating a likelihood function for a given branch by a single probability density function with mean and variance computed based on available soft information on past symbols relative to the branch that is being currently considered.

Low complexity soft demapping

A method of constructing an effective generator polynomial for error correction by which a unique set of syndromes for each error event is produced is provided. The method includes preparing a set of dominant error events from the intersymbol interference characteristics of media; and generating a codeword from the data using a non-primitive generator polynomial that produces a unique syndrome set which can completely specify each dominant error event.

A method of detecting an occurrence of an error event in data and an apparatus for the same are provided. The method includes: preparing an error detection code wherein syndrome sequences for dominant error events are all different; generating a codeword from source data using the error detection code; detecting the occurrence of the dominant error event in the codeword by checking a syndrome computed from the codeword; and determining a type and likely error starting positions of the occurred dominant error event using the syndrome sequences correspond to the syndrome.

Method of detecting occurrence of error event in data and apparatus for the same

An apparatus for dynamic diversity signal reception based upon receiver-side link quality assessments includes two or more antennae. At least one switch is connected to the two or more antennae. A dynamic diversity controller is connected to the at least one switch. The dynamic diversity controller includes a link quality assessor to assess link quality and generate a link characterization value. A diversity configuration selector, responsive to the link characterization value, selectively activates the at least one switch to implement a dynamic diversity configuration. The link quality assessor includes a signal strength analyzer, a modem detector, and/or a MAC layer analyzer to assess the received signal and generate the link characterization value.

Apparatus and method for dynamic diversity based upon receiver-side assessment of link quality

A method and an apparatus for encoding and decoding a modulation code are provided. The method includes: adding an error detection bit(s) to source information; performing k-constraint coding by inserting an error pattern that can be detected using an error detection code into a data stream that violates a k-constraint for a run length limited (RLL) code in a data stream comprising the error detection bit(s) and the source information, and recording the data stream after being k-constraint coded onto a recording medium; and reading the data stream recorded onto the recording medium and determining whether an error is present in the data stream.

Method and apparatus for encoding and decoding modulation code

Demodulation techniques for a wireless communication system make use of a decision feedback equalization (DFE) technique to mitigate the effects of multipath channel characteristics on receiver performance. The techniques may be particularly useful in the demodulation of complementary code keying (CCK) symbols. A demodulator that performs such techniques may include a time-variant or time-invariant matched filter, a feedback intersymbol interference (ISI) canceller, a transform unit, a phase rotation estimator and corrector, a pattern-dependent bias canceller, and a maximum picker for symbol decisions. The transform unit may include a bank of correlators, or alternatively a fast Walsh transform unit.

CCK demodulation via symbol decision feedback equalizer

Techniques are described for detecting error events in codewords detected from data signals transmitted via a communication system. The error events are detected with an error detection code that corresponds to one or more dominant error events for the communication system. The invention develops a class of error detection codes to detect specific error events of known types. In some embodiments, the communication system comprises a recording system. The error detection coding method may be used in conjunction with error correction processing to provide substantial performance gain compared to conventional parity-based post processing methods. For example, the error correction processing may include one or more correlation filters that correspond to the one or more dominant error events for the communication system. A correction module may correct the codeword based on a type of the detected error event and a location of the detected error event in the codeword.

Growing community of inventors

Plymouth, MN, United States of America

Jaekyun Moon