Optex Corporation

Georgia Tech Research Corporation

Samsung Electronics Co., Ltd.

Calimetrics, Inc.

Electronics and Telecommunications Research Institute

At+t Corp.

Lsi Logic Corporation

Korea Advanced Institute of Science and Technology

Cambridge Enterprise Limited

Western Digital Corporation

Universidade Do Porto

Steven W McLaughlin

Jaehong Kim

Jeong-Seok Ha

Seung-Bum Suh

David C Lee

Dong-Ho Kim

Jonathan A Zingman

Demijan Klinc

John L Fan

John M Gerpheide

Dong Seung Kwon

Byung-Jae Kwak

Myeon-Kyun Cho

Robert L Cloke

Arthur Robert Calderbank

Steven Russel Spielman

Patrick J Lee

Aditya Ramamoorthy

Stephen E Ralph

David Warland

Terrence L Wong

Judith C Powelson

Yung-Cheng Lo

Jeongseok Ha

Russell Manning Mersereau

Ketan Mukund Patel

Ronald W Schafer

Yi Ling

Faramarz Fekri

Rajiv Laroia

Richard L Martin

Allen M Earman

Joao Francisco Cordeiro De Oliveira Barros

Laura L McPheters

Matthieu Bloch

Cenk Argon

Andrew Thangaraj

Miguel Raul Dias Rodrigues

Systems and methods of securely communicating from a sender device to a receiver device on a communication channel are disclosed. One disclosed method is for securely communicating from a sender device to a receiver device on a main channel when an eavesdropper device is listening on an eavesdropper channel. The main channel has an signal-to-noise ratio SNR, and the eavesdropper channel has a signal-to-noise ratio SNR. The method comprises encoding a message at a physical layer with a secure error correcting code (SECC) to produce an encoded message, and transmitting the encoded message on the main channel. The SECC has a set of defined characteristics such that when the eavesdropper device is more than a predetermined distance Z from the sender, at least a predefined fraction of the message is unreliable, where the predefined fraction of unreliable bits renders the eavesdropper unable to reliable decode messages on the main channel.

Systems and methods of secure coding for physical layer communication channels

A transmitter device (T) for secure communication includes: an encoder () configured to apply a non-systematic error correcting code (NS ECC) to a message, thus producing encoded bits with no clear message bits; and a transceiver () configured to transmit the encoded bits over a main channel to a receiver. A method for secure communication includes: encoding a message with an NS ECC to produce an encoded message carrying no message bits in the clear; and transmitting the encoded message over a main channel (). The NS ECC characteristics result in an eavesdropper channel error probability under a security threshold () and a main channel error probability over a reliability threshold (), whenever an eavesdropper () listening on an eavesdropper channel () is more than distance Z () from the transmitter. Unreliable bits in the encoded bits render the eavesdropper unable to reliably decode messages on the main channel.

Secure communication using non-systematic error control codes

Systems and methods for selecting a puncturing pattern for a low density parity check (LDPC) code are disclosed. One such method comprises: selecting a puncture pattern distribution for the LDPC code; calculating a security threshold and a reliability threshold for the LDPC, the LDPC having the selected puncture pattern distribution and also described by a degree distribution; storing the selected puncture pattern distribution responsive to a security gap for the LDPC being a lowest value encountered in any prior iterations; selecting another puncture pattern distribution for the LDPC code; and repeating the calculating, the storing, and the selecting another puncture pattern distribution steps.

Secure communication using error correction codes

Systems and methods of providing opportunistic security for physical communication channels are disclosed. One disclosed method is for opportunistic secure communication on a main channel between a sender device and a receiver device when an eavesdropper device is listening on an eavesdropper channel. This example method includes transmitting, in a first time period in which signal quality on the main channel is better than signal quality on the eavesdropper channel, symbols that are randomly selected from a set of symbols. The method also includes transmitting, in a second time period in which signal quality on the main channel is not better than signal quality on the eavesdropper channel, coding information associated with the randomly selected symbols. The method also includes reconciling the randomly selected symbols using the coding information.

Systems and methods for providing opportunistic security for physical communication channels

Disclosed is a method and apparatus for coding in a communication system. The coding method includes generating an information codeword vector from an information vector, generating a first vector in the information vector from an information part of a parity check matrix, generating a first parity codeword vector by performing an exclusive OR operation of the first vector and a second vector corresponding to a cyclically shifted version of the first vector, and generating a second parity codeword vector by performing an exclusive OR operation of the first vector, the first parity codeword vector, and a third vector. The third vector is a cyclically shifted version of a vector resulting from the exclusive OR operation of the first vector, the first parity codeword vector, and a fed-back third vector.

Apparatus and method for coding in communication system

In a communication system, a signal transmission apparatus includes an encoder for encoding an information vector into a low density parity check (LDPC) codeword with an LDPC coding scheme, and a puncturer for puncturing the LDPC codeword according to a coding rate using a puncturing scheme. A signal reception apparatus includes a '0' inserter for inserting '0' symbols in a received signal according to a coding rate used in a signal transmission apparatus, and a decoder for decoding the &#x2018;0&#x2019; symbol-inserted signal with a decoding scheme corresponding to a low density parity check (LDPC) coding scheme used in the signal transmission apparatus, thereby detecting an information vector.

Apparatus and method for transmitting/receiving signal in a communication system

A channel encoding apparatus and method are provided in which part of the parity bits are set to erroneous bits, and full parity bits are created by correcting the erroneous bits using a channel decoding apparatus of a receiver in a communication system. In the channel encoding apparatus, in order to generate a coded bit stream by adding a parity bit stream to a message bit stream, a partial parity generator generates a partial parity bit stream as a part of the parity bit stream using the message bit stream, an erasure generator generates a bit stream having an erroneous value as the remaining part of the parity bit stream, and a decoder calculates the value of the parity bit stream by correcting the bit stream having the erroneous value using a parity-check matrix that determines the parity bit stream, the message bit stream, and the partial parity bit stream.

Channel encoding apparatus and method

A method for puncturing a low density parity check (LDPC) code that is decoded through a parity check matrix expressed by a factor graph including check nodes and bit nodes connected to the check nodes through edges. The method includes classifying the bit nodes mapped to a parity part of a codeword into hierarchical groups according to their decoding facilities when the bit nodes are punctured, determining puncturing order of the groups, and sequentially performing puncturing on the bit nodes from a bit node belonging to a corresponding group according to the puncturing order of the groups to acquire a codeword with a desired coding rate.

Method for puncturing an LDPC channel code

A system and method for enabling efficient error correction and encryption using wavelet transforms over finite fields. The system and method utilizes the combination of a channel encoder and channel decoder to correct errors to source data after transmission over a physical channel or storage in a storage medium. The channel encoder mathematically generates a set of wavelet coefficients by performing a combination of filtering and/or processing of a received message vector. The wavelet coefficients are then utilized by the channel encoder to cause its filters to transform message data into transmission data. The channel decoder receives the transmitted source data in the form of a code word/channel error combination and performs filtering to render a syndrome, representative of the channel error. Analysis of the syndrome is performed to determine the actual error, which is utilized to derive the actual source data.

System and method for enabling efficient error correction and encryption using wavelet transforms over finite fields

A system is described that includes a system for correcting modal dispersion and errors in an optical fiber system. The system includes a multisegment photodetector coupled to an end of an optical fiber for detecting optical signals exiting the optical fiber and for converting the optical signals to an electrical output, the multisegment photodetector including a plurality of photodetector regions configured such that one of the plurality of photodetectors regions intercepts a mode in a manner distinct from another of the plurality of photodetectors. The system also includes logic configured to receive a resultant signal output from the photodetector regions and provide forward error correction decoding of the resultant signal.

Spatially resolved equalization and forward error correction for multimode fiber links

A computer program product, apparatus, and method for correcting errors introduced into a set of data bits during transmission of the set of data bits over a channel includes determining a confidence measure for each data bit based only on the values of one or more of the data bits, each confidence measure representing the probability that the value of the corresponding data bit is correct; and changing the value of a given data bit when the confidence measure for the given data bit indicates that the value of the given data bit is not correct, thereby producing a corrected data bit.

Advanced forward error correction

A system and method are disclosed for reading a multilevel signal from an optical disc. The method includes reading a raw analog data signal from a disc using an optical detector and adjusting the amplitude of the raw analog data signal. A timing signal is recovered from the amplitude adjusted analog data signal and correction is made for amplitude modulation of the raw analog data signal by processing the raw analog data signal and the timing signal.

Method and apparatus for reading and writing a multilevel signal from an optical disc

A system and method for reading data to and writing data from multi-level (M-ary) partial response channels uses a trellis coder to encode an input bit stream sequence into a stream of multi-level data symbols. The data symbols are written to the partial response channel using any of a number of techniques. Preferably, the trellis coder anticipates the modulation transfer function of the partial response channel in encoding the data. Because the partial response channel has its own transfer function, the relationship between the data read from the channel and the actual input data bits is a function not only of the data encoder but also of the partial response channel. Therefore, a decoder specification used to implement the decoder takes into account the effect of the trellis encoder as well as the effect of the partial response channel.

Coding system and method for partial response channels

A storage system employs a method for encoding a sequence of input data blocks into a sequence of codewords. Each input data block includes a first predetermined number of bits (the data block length). Each codeword includes a second predetermined number of bits (the codeword length). The code rate, i.e., the ratio of the first number to the second number, is greater than &frac34;. The method is performed in a sampled-data channel in a storage system; and the channel includes a circuit the performance of which is adversely affected by an excessive run length of bits between occurrences of a predetermined influential pattern. Preferably, the influential pattern is a two-bit sequence of adjacent 1's, which favorably influences the performance of a timing recovery circuit. The method includes receiving the sequence of input data blocks and generating the sequence of codewords responsive to the received sequence of input data blocks. The sequence of codewords has a constraint on the maximum run length of bits between occurrences of the influential pattern, the maximum run length of bits being less than or equal to the codeword length.

Storage system employing high-rate code with constraint on run length between occurrences of an influential pattern

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Rochester, NY, United States of America

Steven W McLaughlin