Abstract:
According to one embodiment of the present invention, a method for transmitting information is disclosed. The method for transmitting information comprises: a step of taking, as an input, an information bit; a step of encoding the information bit to generate a codeword having a length of 48 bits, using a first generating matrix in which the size of a column is the same as the length of the information bit, the number of the rows is 24, and the value of the symbol which is an element of the matrix is 0 or 1; and a step of modulating the thus-generated codeword and transmitting the modulated codeword. The first generating matrix is generated by making perforations in 8 rows from among the original generating matrix which has 32 rows. The step of generating a codeword having a length of 48 bits involves generating the codeword by using a 24-bit codeword generated by the first generating matrix two times.
Abstract:
The invention relates to a method for recovery of lost data and for correction of corrupted data transmitted from a sending device (10) to a receiver device (12), the method comprising the steps: Encoding the data by an encoder (14) connected to the sending device ( 10) Transmitting the data from the sending device (10) to the receiver device (12) via a transmitting device (18) and Decoding the data by a decoder ( 16) connected to the receiver device ( 12), whereby lost and/or corrupted data is recovered during decoding is conducted by solving the system of equations of a parity check matrix H. A transmitted codeword is divided on the receiver side into a correctly received part and a missing part and the equation holds: Formula (1). The matrix Formula (a) is manipulated so that its lower part contains only zero entries leading to the equation Formula (2). Formula (b) corresponds to some unknown codeword symbols and x' K corresponds to known codeword symbols. Formula (a) is the part of the parity check matrix H corresponding to the missing part of the codeword Formula (c) and H K is the part of the parity check matrix H corresponding to the correctly received part of the codeword x K . The method further comprises the following method steps: Multiplying correctly received symbols x' K with the corresponding part H' K , whereby this multiplication yields in a syndrome s', Checking the lower b-a rows of the syndrome s' for non-zero entries, whereby a row vector e is generated containing 1 if a non-zero entry is found, otherwise zero. The method is characterized by the following method steps for correcting a single erroneous symbol in the transmitted codeword : If all non-zero entries of s" are the same, checking which columns of H" K as lower part of H' K are equal to the vector e, whereby if exactly one column of the part Η' K is identified the corresponding erroneous symbol in the codeword is identified and the erroneous symbol in the codeword is corrected by subtraction of the identified non-zero value from the erroneous symbol, whereby in case of a single error all non-zero entries in the b-a lower rows of the syndrome s' are equal.
Abstract:
k input bits are encoded according to a code with which is associated a m x n=m+k parity check matrix H. The resulting codeword is punctured, with n' bits. The punctured codeword is exported to a corrupting medium such as a communication channel or a memory. A representation of the punctured codeword is imported from the corrupting medium and is decoded using a matrix H' that is smaller than H. For example, H' is m'=m~(n-n ') x n' and is derived by merging selected rows of H. Alternatively, H has at most m rows and fewer than n columns but more than n' columns. Alternatively, H has fewer than m'=m-(n-n') rows and fewer than n' columns.
Abstract:
A method implemented in a digital subscriber line (DSL) system is described for minimizing a misdetection probability at a far-end coded message receiver during transmission of a coded message. The method comprises jointly determining, at the far-end coded message receiver, a P matrix and a modulation scheme. The method further comprises encoding a message into a coded message with a systematic linear block code, the systematic linear block code having a generator matrix [I P], where I represents a linear block code component identity matrix and P represents the determined P matrix. The method also comprises modulating the encoded message to one or more tones forming a discrete multi-tone (DMT) symbol according to the determined modulation scheme.
Abstract:
Techniques to support low density parity check (LDPC) encoding and decoding are described. In an aspect, LDPC encoding and decoding of packets of varying sizes may be supported with a set of base parity check matrices of different dimensions and a set of lifting values of different powers of two. A base parity check matrix G of dimension m B Œn B may be used to encode a packet of k B =n B -m B information bits to obtain a codeword of n B code bits. This base parity check matrix may be "lifted" by a lifting value of L to obtain a lifted parity check matrix H of dimension L⋅m B ŒL⋅n B . The lifted parity check matrix may be used to encode a packet of up to L⋅k B information bits to obtain a codeword of L⋅n B code bits. A wide range of packet sizes may be supported with the set of base parity check matrices and the set of lifting values.
Abstract translation:描述了支持低密度奇偶校验(LDPC)编码和解码的技术。 在一方面,可以用不同维度的一组基本奇偶校验矩阵和两个不同功率的提升值的集合来支持不同大小的分组的LDPC编码和解码。 可以使用尺寸为m B的基本奇偶校验矩阵G来编码k B = N B B的分组, / SUBB信息比特,以获得n个比特码的码字。 该基本奇偶校验矩阵可以通过提升值L“提升”,以获得尺寸为L·m B·B·H B B的提升奇偶校验矩阵H. 提升的奇偶校验矩阵可以用于编码高达L·k个B信息比特的分组,以获得L·n个B个码比特的码字。 可以使用一组基本奇偶校验矩阵和提升值集来支持大范围的分组大小。
Abstract:
A decoder (100) for decoding a noisy received word to obtain an estimate of a transmitted word, the noisy received word being based on an encoding rule enabling at least a first and a second parity-check criterion. The decoder (100) comprises the first decoder (110) for decoding the noisy received word based on the first parity-check criterion and to obtain a first estimate of the transmitted code and a second decoder (120) for decoding the noisy transmitted word based on the second parity-check criterion and to obtain a second estimate of the transmitted word or for modifying a noisy received word according to an automorphism of the encoding rule to obtain a modified received word and for decoding the modified received word based on the first parity-check criterion and to obtain the second estimate of the transmitted word. The decoder (100) further comprises a selector (130) for selecting the first or the second estimate of the transmitted word as the estimate of the transmitted word based on the noisy received word.
Abstract:
In an encoder for encoding symbols of data using a computing device having memory constraints, a method of performing a transformation comprising loading a source block into memory of the computing device, performing an intermediate transformation of less than all of the source block, then replacing a part of the source block with intermediate results in the memory and then completing the transformation such that output symbols stored in the memory form a set of encoded symbols. A decoder can perform decoding steps in an order that allows for use of substantially the same memory for storing the received data and the decoded source block, performing as in-place transformations. Using an in-place transformation, a large portion of memory set aside for received data can be overwritten as that received data is transformed into decoded source data without requiring a similar sized large portion of memory for the decoded source data.