Resumes
Resumes
Inkyu Lee Phones & Addresses
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Rolling Hills Estates, CA
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Scarsdale, NY
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20 Midland Ave, Kearny, NJ 07032 (201) 246-8306
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Newton Center, MA
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White Plains, NY
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Dobbs Ferry, NY
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Allentown, PA
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Palisades Park, NJ
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Palo Alto, CA
Publications
Us Patents
Generating Reliability Values For Iterative Decoding Of Block Codes
View pageUS Patent:
6421804, Jul 16, 2002
Filed:
Dec 20, 1999
Appl. No.:
09/468400
Inventors:
Inkyu Lee - Kearny NJ
Assignee:
Agere Systems Guardian Corp. - Miami Lakes FL
International Classification:
H03M 1329
US Classification:
714755, 714780
Abstract:
An iterative decoder arranges calculation of updated reliability values for a current iteration of an iterative decoder so as to reduce the number of comparison operations. The variables for the magnitude and sign of the updated reliability value are initialized. A search of the previous reliability values generates first and second minimum magnitude values for each row (if the iterative decoder is decoding in the horizontal direction) or column (if the iterative decoder is decoding in the vertical direction). A test determines whether the magnitude of the previous reliability value is greater than the first minimum magnitude value m. If so, the magnitude of the updated reliability value is set as the value m. Otherwise, the magnitude of the updated reliability value is set as the second minimum magnitude value m. The sign of the updated reliability value is tracked and assigned once the updated reliability value is set.
Iterative Decoding Of Concatenated Codes For Recording Systems
View pageUS Patent:
6516136, Feb 4, 2003
Filed:
Jul 6, 1999
Appl. No.:
09/347983
Inventors:
Inkyu Lee - Kearny NJ
Assignee:
Agere Systems Inc. - Allentown PA
International Classification:
H04N 576
US Classification:
386124, 386 46, 360 48, 36912401
Abstract:
A data recording system employs parallel iterative decoding of soft output samples representing encoded data read from a storage medium. The iterative decoder reads packets of data from a sector of the medium, each packet containing soft output samples representing data encoded with a concatenated code formed from N component codes, N a positive integer. The iterative decoder employs I decoding iterations, I a positive integer. Each packet has a length substantially equal to the sector length divided by N. For an exemplary magnetic recording system, encoded data read from a sector of a magnetic medium is partitioned into N packets of length 4096/N. The first packet is passed to the first component code decoder of a parallel iterative decoder. When the second packet is ready to be passed to the first component code decoder, the decoded output values of the first packet in the first decoder are passed to the second component code decoder. The second packet is then applied to the first component code decoder.
Iterative Decoding Of Data Packets Employing Decision Feedback Equalization
View pageUS Patent:
6570919, May 27, 2003
Filed:
Jul 30, 1999
Appl. No.:
09/363743
Inventors:
Inkyu Lee - Kearny NJ
Assignee:
Agere Systems Inc. - Allentown PA
International Classification:
H03K 508
US Classification:
375233, 375232
Abstract:
A data transmission system employs an iterative decoder that applies decision feedback equalization (DFE) to channel output samples of a packet of data. The iterative decoder receives a stream of channel output samples as packets that may, for example, be read from a sector of a recording medium. Each packet may represent user data encoded, for example, with a concatenated code formed from N component codes, N a positive integer. The iterative decoder employs I decoding iterations, I a positive integer. DFE employs two filters: a feedforward filter and a feedback filter. The feedforward filter, which may be a whitened-matched filter used for detection, shifts dispersed channel output energy into the current sample. The feedback filter cancels energy of trailing inter-symbol interference from previous symbols. In each iteration by the iterative decoder, the DFE is applied to channel output samples of a packet by filtering with the feedforward filter, and then filtering with the feedback filter to cancel interference energy in the current sample from previous samples.
Iterative Decoding With Post-Processing Of Detected Encoded Data
View pageUS Patent:
6581182, Jun 17, 2003
Filed:
May 15, 2000
Appl. No.:
09/570764
Inventors:
Inkyu Lee - Kearny NJ
Assignee:
Agere Systems Inc. - Allentown PA
International Classification:
H03M 1303
US Classification:
714795, 714780, 375262, 375341
Abstract:
An iterative decoder employs detection and post-processing of channel output samples to generate soft output vales for encoded data provided to the decoder for one or more iterations of decoding. The channel output samples account for user data encoded with concatenated codes. For one or more other iterations, the reliability values of the soft values of the prior iteration are updated, generating soft output data for the decoder for the current iteration of decoding. A detector may use a soft-output Viterbi algorithm (SOVA) to detect encoded data from channel output samples, and the SOVA algorithm may be implemented by a Viterbi algorithm generating hard decisions from the output channel samples followed by post-processing to generate and update reliability values for the soft-output values based on the hard decisions and output channel samples. In one implementation, generating soft-output values from output channel samples by a detector employs the full soft-output Viterbi algorithm (SOVA) during the first iteration. For subsequent iterations, the post-processor of the full SOVA algorithm is used without a Viterbi detector.
Method And Apparatus For Extracting Reliability Information From Partial Response Channels
View pageUS Patent:
6587987, Jul 1, 2003
Filed:
Jul 7, 2000
Appl. No.:
09/611887
Inventors:
Bane V. Vasic - Allentown PA
Inkyu Lee - Kearny NJ
Jeffrey L. Sonntag - Allentown PA
Inkyu Lee - Kearny NJ
Jeffrey L. Sonntag - Allentown PA
Assignee:
Lucent Technologies Inc. - Murray Hill NJ
International Classification:
H03M 1300
US Classification:
714780
Abstract:
The present invention is a method and system for generating soft outputs by taking advantage of the fact that, in PR channels, there exists a set of error event sequences that occurs more often than others. This results in a soft output extractor with significantly lower complexity than the prior art SOVA system. Minimum distance error event sequences are identified and soft information or bit reliabilities are extracted from the PR channel based on the identified sequences. The soft information is then used by an iterative error control decoder correct errors more efficiently.
Interative Decoding Based On Dominant Error Events
View pageUS Patent:
6691263, Feb 10, 2004
Filed:
May 3, 2001
Appl. No.:
09/847953
Inventors:
Bane V. Vasic - Tucson AZ
Jeffrey L. Sonntag - Portland OR
Inkyu Lee - Kearny NJ
Jeffrey L. Sonntag - Portland OR
Inkyu Lee - Kearny NJ
Assignee:
Agere Systems Inc. - Allentown PA
International Classification:
H03M 1341
US Classification:
714709, 714780, 714794
Abstract:
An iterative decoding system for intersymbol interference (ISI) channels has a module for extracting bit reliabilities from a partial response (PR) channel, an iterative decoder, and a module for updating the bit reliabilities. A transmitter parses a data sequence into blocks that are encoded to generate a sequence of codewords. By encoding, a correlation among the bits of each codeword output to the PR channel is created. A maximum likelihood sequence detector (MLSD) in the receiver produces estimates of transmitted bits from samples of the output from the PR channel. The MLSD detector has a priori knowledge of typical error events that can occur during transmission through the channel. Along with the bit estimates, at each time instant the MLSD detector generates set of error event likelihoods. These error event likelihoods are then converted into bit reliabilities that, together with estimates for the transmitted bits, are used to recalculate the bit reliabilities using the knowledge of the relation between bits within a codeword. The iterative decoder uses this soft input information (bit reliabilities and bit estimates) for each iteration of decoding to improve i) the estimate of the bit reliabilities, ii) the decisions of what bit has been transmitted, and iii) calculations for the error event likelihoods for the next iteration.
Generating Log-Likelihood Values In A Maximum A Posteriori Processor
View pageUS Patent:
6760883, Jul 6, 2004
Filed:
Sep 13, 2001
Appl. No.:
09/951660
Inventors:
Inkyu Lee - Kearny NJ
Assignee:
Agere Systems Inc. - Allentown PA
International Classification:
H03M 1303
US Classification:
714794, 714792, 714781
Abstract:
A maximum a posteriori (MAP) detector/decoder employs an algorithm that computes log-likelihood value with an a posteriori probability (APP) value employing a number N of previous state sequences greater than or equal to two (N 2). By defining the APP with more previous state sequences, the set of values may be calculated for a current state and then reduced. After generating the reduced set of values, the full set of values may be generated for calculation of log-likelihood values. By calculating a set of values that may be decimated by, for example, N, the amount of memory required to store the values used in subsequent computations is reduced.
Reduced Complexity Receiver For Space-Time- Bit-Interleaved Coded Modulation
View pageUS Patent:
7095812, Aug 22, 2006
Filed:
Jun 24, 2002
Appl. No.:
10/178922
Inventors:
Albert Chan - Cambridge MA, US
Inkyu Lee - Kearny NJ, US
Carl-Erik Wilhelm Sundberg - Chatham NJ, US
Inkyu Lee - Kearny NJ, US
Carl-Erik Wilhelm Sundberg - Chatham NJ, US
Assignee:
Agere Systems Inc. - Allentown PA
International Classification:
H03D 1/00
H04L 27/06
H04L 27/06
US Classification:
375341, 375262, 714786
Abstract:
A system employs space-time coding characterized at the transmitter by bit-interleaved coded modulation (BICM) combined with modulating several streams of the BICM encoded data for transmission over two or more antennas. Space-time coding techniques improve transmission efficiency in radio channels by using multiple transmit and/or receive antennas and coordination of the signaling over these antennas. Bit-interleaved coded modulation provides good diversity gain with higher-order modulation schemes that employ binary convolutional codes. A receiver demodulates the received signals and applies multi-input, multi-output (MIMO) demapping to estimate the BICM encoded bitstream. After deinterleaving of the BICM encoded bitstream, maximum a posteriori (MAP) decoding is applied to the resulting bit stream to generate soft output values. By applying well-known turbo-decoding principles to iteratively demap and decode, the overall receiver performance is significantly improved. The MIMO demapping and MAP decoding processes exchange likelihood information to improve the bit error rate performance over several iterations of demapping/decoding.