公开(公告)号：US20020136317A1

公开(公告)日：2002-09-26

申请号：US10045810

申请日：2002-01-11

申请人： International Business Machines Corporation

发明人： Sedat Oelcer ,  Evangelos S. Eleftheriou

IPC分类号： H04L005/12

CPC分类号： H04L1/0057 ,  H04L1/007 ,  H04L27/3427

摘要： Methods, apparatus and systems for multilevel data communication comprises dividing a set of information bits to be transmitted into a first group and a second group; encoding the first group to generate a block code, selecting a subset of symbols in a constellation of symbols in dependence on the block code according to a Gray-coded mapping function, selecting a symbol within the subset in dependence on the second group according to a Gray-coded mapping function, and transmitting the selected symbol.

摘要翻译： 用于多电平数据通信的方法，装置和系统包括将要发送的一组信息比特划分成第一组和第二组; 编码所述第一组以生成块码，根据格雷编码映射函数，根据所述块码选择码元星座中的符号子集，根据所述第二组，根据所述第二组选择所述子集内的符号 灰色编码映射功能，并传输所选择的符号。

公开(公告)号：US20030037298A1

公开(公告)日：2003-02-20

申请号：US09902859

申请日：2001-07-11

申请人： International Business Machines Corporation

发明人： Evangelos Stavros Eleftheriou ,  Richard Leo Galbraith ,  Sedat Oelcer

IPC分类号： H03M013/00

CPC分类号： H04L1/0058 ,  G11B20/1833 ,  H03M13/1162 ,  H03M13/118 ,  H03M13/255

摘要： A method for low-density parity-check (LDPC) encoding of data comprises defining a first MnullN parity check matrix; generating, based on the first parity check matrix, a second parity check matrix having an MnullM triangular sub-matrix; and, mapping the data into an LDPC code word based on the second parity check matrix. The method is particularly useful for data communications applications, but may also be employed in other applications such as, for example, data storage.

摘要翻译： 用于数据的低密度奇偶校验（LDPC）编码的方法包括定义第一M×N奇偶校验矩阵; 基于所述第一奇偶校验矩阵生成具有M×M三角形子矩阵的第二奇偶校验矩阵; 以及基于第二奇偶校验矩阵将数据映射到LDPC码字。 该方法对于数据通信应用特别有用，但也可以用于其他应用中，例如数据存储。

公开(公告)号：US20030074626A1

公开(公告)日：2003-04-17

申请号：US10044624

申请日：2002-01-08

申请人： International Business Machines Corporation

发明人： Jon Coker ,  Ajay Dholakia ,  Evangelos S. Eleftheriou ,  Rick Galbraith ,  Thomas Mittelholzer ,  Sedat Oelcer

IPC分类号： H03M013/00

CPC分类号： H03M13/112 ,  H03M13/1117 ,  H03M13/1515 ,  H03M13/255 ,  H03M13/2906 ,  H03M13/6331 ,  H03M13/6583

摘要： A method for decoding Low Density Parity Check (LDPC) codes comprises executing a sum product algorithm to recover a set of information bits from an LDPC code represented as a bipartite graph of symbol nodes and check nodes, the sum product algorithm being responsive to input log likelihood ratios associated with the symbol nodes. The check nodes are updated by generating a set of forward difference metrics and a set of backward difference metrics in dependence on the ratios of logarithmic probabilities each associated with a corresponding symbol node of the LDPC code, updating each metric in the set of forward difference metrics in dependence on the absolute value of the log likelihood ratio associated with the symbol node and the absolute value of the previous metric in the set, updating each metric in the set of backward difference metrics in dependence on the absolute value of the log likelihood ratio associated with the symbol node and the absolute value of the previous metric in the set, and generating log likelihood ratios to be propagated back to each symbol node in dependence on the updated sets of forward and backward difference metrics.

摘要翻译： 用于解码低密度奇偶校验（LDPC）码的方法包括执行和积乘法算法以从表示为符号节点和校验节点的二分图的LDPC码中恢复一组信息比特，所述和积算法响应于输入日志 与符号节点相关联的似然比。 通过根据与LDPC码的对应符号节点相关联的对数概率的比率生成一组前向差分量度和一组后向差分度量来更新校验节点，更新该组前向差分度量中的每个度量 根据与符号节点相关联的对数似然比的绝对值和集合中先前度量的绝对值，根据相关联的对数似然比的绝对值来更新该组后向差分度量中的每个度量 符号节点和集合中先前度量的绝对值，并且根据更新的前向和后向差分度量集合，生成要传播回每个符号节点的对数似然比。

公开(公告)号：US20020136284A1

公开(公告)日：2002-09-26

申请号：US09814044

申请日：2001-03-21

申请人： International Business Machines Corporation

发明人： Gordon Taylor Davis ,  Jeffrey Haskell Derby ,  Evangelos Stavros Eleftheriou ,  Sedat Oelcer ,  Malcolm Scott Ware

IPC分类号： H04B001/38

CPC分类号： H04L25/028 ,  H04L27/2626 ,  H04M11/062 ,  Y02D50/44

摘要： A low power DSL modem transmitter, suitable for incorporation in integrated DSLAM server line cards, transmits full power physical frames which include a control channel and a data field when data is available for transmission and physical frames having only a control channel or a control channel and a low power synchronization field when data is not available for transmission. And a method for controlling the total power dissipated in the integrated DSLAM by selectively restricting the flow of data packets to the DSLs.

摘要翻译： 适用于集成DSLAM服务器线路卡的低功率DSL调制解调器发射机在数据可用于传输和仅具有控制信道或控制信道的物理帧的情况下传输包括控制信道和数据字段的全功率物理帧， 当数据不可用于传输时的低功率同步字段。 以及一种用于通过选择性地限制数据分组到DSL的流量来控制在集成DSLAM中消耗的总功率的方法。

公开(公告)号：US20020136283A1

公开(公告)日：2002-09-26

申请号：US09813558

申请日：2001-03-21

申请人： International Business Machines Corporation

发明人： Gordon Taylor Davis ,  Jeffrey Haskell Derby ,  Evangelos Stavros Eleftheriou ,  Sedat Oelcer ,  Malcolm Scott Ware

IPC分类号： H04B001/38 ,  H04L005/16

CPC分类号： H04L5/14 ,  H04L5/023

摘要： A shared digital subscriber line modem achieves reduced total power consumption and data security by generating and transmitting a physical data frame which includes a control channel and a data field to only the connected client modem associated with the intended recipient. A second physical frame which does not include the data field is generated and transmitted to all of the other connected client modems. This method results in a reduction in the power required and provides improved data security by preventing data access to non-addressed client modems.

摘要翻译： 共享数字用户线路调制解调器通过仅向与预期接收者相关联的连接的客户端调制解调器生成并发送包括控制信道和数据字段的物理数据帧来实现减少的总功耗和数据安全性。 不包括数据字段的第二物理帧被生成并发送到所有其他连接的客户端调制解调器。 这种方法导致所需功率的降低，并且通过防止数据访问未被寻址的客户端调制解调器来提供改进的数据安全性。