公开(公告)号：US20090310658A1

公开(公告)日：2009-12-17

申请号：US12138657

申请日：2008-06-13

Applicant: Rahul Garg ,  Patrick Duvaut ,  Amitkumar Mahadevan ,  Harish Jethanandani

Inventor： Rahul Garg ,  Patrick Duvaut ,  Amitkumar Mahadevan ,  Harish Jethanandani

IPC: H04B1/38

CPC classification number: H04M11/062

Abstract: Systems and methods for reducing the peak-to-average ratio (PAR) at the transmitter can reduce the dynamic range required in various analog components. PAR can be reduced by applying a time-domain compensation signal which reduces the magnitude of peaks in the time-domain signal prior to transmission where the time-domain compensation signals use tones that are reserved for the purpose of reducing the PAR. The reservation of these reserved tones for PAR can be implemented by altering the typical startup procedures in a digital subscriber line (xDSL) system. The use of the reserved tones to reduce the PAR can be implemented using a low complexity algorithm or using an adaptive technique.

Abstract translation: 用于降低发射机峰值平均比（PAR）的系统和方法可以减少各种模拟组件所需的动态范围。 可以通过应用时域补偿信号来减小PAR，该时域补偿信号在时域补偿信号使用为了减少PAR的目的而被保留的音调的同时减小时域信号中的峰值的幅度。 可以通过改变数字用户线（xDSL）系统中的典型启动过程来实现用于PAR的这些保留音调的预留。 可以使用低复杂度算法或使用自适应技术来实现使用保留的音调来减少PAR。

公开(公告)号：US20090245340A1

公开(公告)日：2009-10-01

申请号：US12412191

申请日：2009-03-26

Applicant: Massimo Sorbara ,  Patrick Duvaut ,  Amitkumar Mahadevan ,  Laurent Francis Alloin

Inventor： Massimo Sorbara ,  Patrick Duvaut ,  Amitkumar Mahadevan ,  Laurent Francis Alloin

IPC: H04B17/00

CPC classification number: H04L1/0045 ,  H04L1/1671 ,  H04L1/243

Abstract: The measurement of far-end crosstalk (FEXT) in a Digital Subscriber Line communications is instrumental in the ability of using a multiple input multiple output (MIMO) pre-coder to cancel FEXT. A reliable robust back channel for transmission of error is instrumental to provide error samples for the proper operation of a MIMO pre-coder. Bins can be dedicated to insure bandwidth from the customer premises equipment (CPE) to the central office (CO). By increasing the margin used in the bins, robustness can be added to this back channel between the CPE and CO.

Abstract translation: 数字用户线路通信中远端串扰（FEXT）的测量有助于使用多输入多输出（MIMO）预编码器取消FEXT。 用于错误传输的可靠的鲁棒后置信道对于为MIMO预编码器的正确操作提供错误样本是有用的。 可以专门用于保护客户端设备（CPE）到中心局（CO）的带宽。 通过增加机箱中使用的余量，可以在CPE和CO之间的后向通道中增加鲁棒性。

公开(公告)号：US20090122855A1

公开(公告)日：2009-05-14

申请号：US12123925

申请日：2008-05-20

Applicant: Patrick Duvaut ,  Amitkumar Mahadevan ,  Pravesh Biyani ,  Shailendra Singh ,  Satyavardhan Maheshwari

Inventor： Patrick Duvaut ,  Amitkumar Mahadevan ,  Pravesh Biyani ,  Shailendra Singh ,  Satyavardhan Maheshwari

IPC: H04L27/01 ,  H04L27/06

CPC classification number: H04L25/03159 ,  H04B3/32 ,  H04L27/2601 ,  H04L2025/03426 ,  H04L2025/03522

Abstract: Systems and methods for mitigating the effects of self-FEXT within an xDSL system are described. At least one embodiment is a method for reducing self-induced far end crosstalk (self-FEXT) in a multiple input multiple output (MIMO) digital subscriber line (xDSL) system. The method comprises deriving an initial value for an off-diagonal multiple input multiple output canceller (ODMC) while the ODMC is inactive and while in data mode. The method further comprises activating the initial ODMC and converging towards an steady-state value for the ODMC by performing an adaptive algorithm to maximize the Shannon's capacity of the system and to reduce upstream self-FEXT. The method also comprises performing bit loading and updating a frequency domain equalizer (FEQ).

Abstract translation: 描述了在xDSL系统中减轻自身FEXT影响的系统和方法。 至少一个实施例是用于减少多输入多输出（MIMO）数字用户线（xDSL）系统中的自感应远端串扰（self-FEXT）的方法。 该方法包括：当ODMC处于非活动状态并处于数据模式时，得到非对角多输入多输出消除器（ODMC）的初始值。 该方法还包括通过执行自适应算法激活初始ODMC并朝向ODMC的稳态值收敛，以使香农的系统容量最大化并减少上游自FEXT。 该方法还包括执行比特加载和更新频域均衡器（FEQ）。

公开(公告)号：US20080298555A1

公开(公告)日：2008-12-04

申请号：US12044443

申请日：2008-03-07

Applicant: Patrick Duvaut ,  Amitkumar Mahadevan ,  Vaibhav Dinesh

Inventor： Patrick Duvaut ,  Amitkumar Mahadevan ,  Vaibhav Dinesh

IPC: H04M3/30

CPC classification number: H04M3/302 ,  H04M3/085

Abstract: Systems and methods for performing loop length estimation are described. One embodiment includes a method which comprises receiving an echo signal for a loop under test where the echo signal is a per-port calibrated echo response obtained using frequency domain reflectometry single-ended line testing (FDR-SELT). The method further comprises analyzing characteristics of the echo signal to perform a loop length estimation based on data relating to ripple frequency as a function of loop length.

Abstract translation: 描述了用于执行环路长度估计的系统和方法。 一个实施例包括一种方法，其包括接收用于测试环路的回波信号，其中回波信号是使用频域反射测量单端线测试（FDR-SELT）获得的每端口校准的回波响应。 该方法还包括分析回波信号的特性，以便根据与纹波频率相关的数据作为循环长度的函数来执行环路长度估计。

公开(公告)号：US20080240368A1

公开(公告)日：2008-10-02

申请号：US12044489

申请日：2008-03-07

Applicant: Patrick Duvaut ,  Amitkumar Mahadevan ,  Vaibhav Dinesh

Inventor： Patrick Duvaut ,  Amitkumar Mahadevan ,  Vaibhav Dinesh

IPC: H04M3/08

CPC classification number: H04M3/302 ,  H04M3/085

Abstract: Systems and methods for performing bridge tap detection are described. One embodiment is a method which comprises receiving an echo signal for a loop under test where the echo signal is a per-port calibrated echo response obtained using frequency domain reflectometry single-ended line testing (FDR-SELT). The method further comprises analyzing the echo signal to determine whether differentiating features are present in the per-port calibrated echo signal in order to determine whether the loop under test is a bridge tapped loop.

Abstract translation: 描述了用于执行桥接抽头检测的系统和方法。 一个实施例是一种方法，其包括接收用于测试环路的回波信号，其中回波信号是使用频域反射测量单端线测试（FDR-SELT）获得的每端口校准的回波响应。 该方法还包括分析回波信号以确定在每端口校准的回波信号中是否存在微分特征，以便确定被测环路是否是桥接抽头循环。

公开(公告)号：US20060193400A1

公开(公告)日：2006-08-31

申请号：US10890134

申请日：2004-07-14

Applicant: Joel Morris ,  Ronald Holzloehner ,  Amitkumar Mahadevan ,  Curtis Menyuk ,  John Zweck

Inventor： Joel Morris ,  Ronald Holzloehner ,  Amitkumar Mahadevan ,  Curtis Menyuk ,  John Zweck

IPC: H04L27/06

CPC classification number: H04L1/203

Abstract: A dual adaptive importance-sampling system and method is provided that can estimate the probability of events by combining dual complementary importance-sampling simulations. The present invention exploits the ability to determine an optimal biased pdf using an iterative procedure that requires relatively little a priori knowledge of how to bias. Hence, the present invention is particularly suited for evaluating the BERs and/or WERs of coded communication and storage systems, and is generally applicable to arbitrarily chosen codes. When applied to coded communication and storage systems, the present invention provides a versatile technique for the fast and accurate estimation of BERs and WERs of FEC codes down to values of 10−20 or lower.

Abstract translation: 提供了一种双重自适应重要性抽样系统和方法，可以通过组合双重互补重要性抽样模拟来估计事件的概率。 本发明利用了使用迭代过程确定最佳偏差pdf的能力，该迭代过程需要相对较少的如何偏向的先验知识。 因此，本发明特别适用于评估编码的通信和存储系统的BER和/或WER，并且通常适用于任意选择的代码。 当应用于编码通信和存储系统时，本发明提供了一种通用技术，用于将FEC码的BER和WER的快速和准确估计降低到10至20或更低的值。

公开(公告)号：US08644127B2

公开(公告)日：2014-02-04

申请号：US12713482

申请日：2010-02-26

Applicant: Pravesh Biyani ,  Laurent Francis Alloin ,  Shankar Prakriya ,  Surendra Prasad ,  Amitkumar Mahadevan

Inventor： Pravesh Biyani ,  Laurent Francis Alloin ,  Shankar Prakriya ,  Surendra Prasad ,  Amitkumar Mahadevan

IPC: H04J1/12 ,  H04B3/32

CPC classification number: H04B3/32 ,  H04J1/12 ,  H04L2025/03414 ,  H04L2025/03426

Abstract: Systems and methods for partial self-FEXT (far-end crosstalk) are described. One method, among others, comprises determining one or more instantaneous characteristics of an input signal, wherein the one or more instantaneous characteristics comprise one or more of amplitude of the input signal and an energy level of the input signal. The method further comprises selecting one or more disturbers to cancel according to the one or more instantaneous characteristics, wherein selecting one or more disturbers is performed on a per-DMT (discrete multi-tone) symbol basis.

Abstract translation: 描述了部分自FEXT（远端串扰）的系统和方法。 一种方法包括确定输入信号的一个或多个瞬时特性，其中一个或多个瞬时特性包括输入信号的幅度和输入信号的能级中的一个或多个。 该方法还包括根据一个或多个瞬时特性选择一个或多个干扰器来取消，其中，对每个DMT（离散多音调）符号进行选择一个或多个干扰器。

公开(公告)号：US08300771B2

公开(公告)日：2012-10-30

申请号：US12325541

申请日：2008-12-01

Applicant: Vaibhav Dinesh ,  Kunal Raheja ,  Amitkumar Mahadevan ,  Patrick Duvaut

Inventor： Vaibhav Dinesh ,  Kunal Raheja ,  Amitkumar Mahadevan ,  Patrick Duvaut

IPC: H04M1/24 ,  H04M3/08 ,  H04M3/22

CPC classification number: H04M3/302

Abstract: Disclosed are various embodiments for determining a state of loop termination. One embodiment comprises receiving an un-calibrated echo signal for the loop under test using frequency domain reflectometry single-ended line testing (FDR-SELT) and determining the state of loop termination based on phase of the un-calibrated echo signal. The step of determining the state of loop termination comprises determining whether the loop is terminated by an open termination or a short termination by correlating the phase of the echo signal with an expected phase of the echo signal derived from measurements taken at the same loop length for open and short terminations. For other embodiments, the amplitude of the un-calibrated echo signal is analyzed to determine whether the loop is terminated by a matched-impedance termination.

Abstract translation: 公开了用于确定环路终止状态的各种实施例。 一个实施例包括使用频域反射测试单端线测试（FDR-SELT）接收待测环路的未校准回波信号，并且基于未经校准的回波信号的相位确定环路终止状态。 确定环路终止状态的步骤包括通过将回波信号的相位与从在相同环路长度处获取的测量得到的回波信号的预期相位相关联来确定环路是否由开放终止或短终端终止， 开放和短暂终止。 对于其他实施例，分析未校准的回波信号的幅度，以确定环路是否由匹配阻抗终端终止。

公开(公告)号：US20120020418A1

公开(公告)日：2012-01-26

申请号：US13189095

申请日：2011-07-22

Applicant: Nicholas Philip Sands ,  Stephanie Felicia Pereira ,  Darren Bradley Hutchinson ,  Kevin D. Fisher ,  Amitkumar Mahadevan

Inventor： Nicholas Philip Sands ,  Stephanie Felicia Pereira ,  Darren Bradley Hutchinson ,  Kevin D. Fisher ,  Amitkumar Mahadevan

IPC: H04L27/00

CPC classification number: H04B3/32

Abstract: The memory storage, transmission and processing demands of a vectored DSL system are reduced by sampling a subset of DSL tones in the DSL tone range used in the vectored system. This data is smoothed (denoised) to further reduce the data's size, sacrificing some fidelity or precision as a result. Finally, lossless entropy coding or the like is performed to encode the FEXT cancellation data for storage and use. The resulting data is less likely to cause transmission bottlenecks in the vectored system, can be stored and used more efficiently for both on-chip and off-chip vectoring implementations, and can be readily updated in various ways.

Abstract translation: 矢量DSL系统的存储器存储，传输和处理需求通过在矢量系统中使用的DSL音调范围中采样DSL音调的子集来减少。 该数据被平滑（去噪），以进一步减少数据的大小，从而牺牲一些保真度或精度。 最后，执行无损熵编码等以对用于存储和使用的FEXT取消数据进行编码。 所得到的数据不太可能导致向量系统中的传输瓶颈，可以在片上和片外向量实现方面更有效地存储和使用，并且可以以各种方式容易地更新。

公开(公告)号：US20110200140A1

公开(公告)日：2011-08-18

申请号：US13091651

申请日：2011-04-21

Applicant: Patrick Duvaut ,  Amitkumar Mahadevan ,  Massimo Sorbara ,  Ehud Langberg

Inventor： Patrick Duvaut ,  Amitkumar Mahadevan ,  Massimo Sorbara ,  Ehud Langberg

IPC: H04L25/49

CPC classification number: H04B3/32 ,  H04L1/0042

Abstract: One embodiment is a method for precoding data for transmission in a discrete multi-tone (DMT) system to cancel self-induced far end crosstalk (self-FEXT). The method comprises learning, by the system, characteristics associated with a plurality of N users within a digital subscriber line (xDSL) system to determine an initial off-diagonal multiple input multiple output (MIMO) precoder (ODMP) for a given tone frequency and converging towards an ODMP from the initial ODMP to cancel self-FEXT for the plurality of N users, wherein the ODMP is represented as a zero diagonal matrix containing only off-diagonal terms.

Abstract translation: 一个实施例是用于在离散多音（DMT）系统中预编码用于传输的数据以消除自感应远端串扰（self-FEXT）的方法。 该方法包括通过系统学习与数字用户线（xDSL）系统内的多个N个用户相关联的特征，以确定给定音频的初始非对角多输入多输出（MIMO）预编码器（ODMP），以及 从初始ODMP收敛到ODMP以取消多个N个用户的自身FEXT，其中ODMP被表示为仅包含非对角项的零对角矩阵。