公开(公告)号：US20080089485A1

公开(公告)日：2008-04-17

申请号：US11865817

申请日：2007-10-02

Applicant: Patrick Duvaut ,  Amitkumar Mahadevan ,  Feng Ouyang

Inventor： Patrick Duvaut ,  Amitkumar Mahadevan ,  Feng Ouyang

IPC: H04M1/24

CPC classification number: H04M1/24

Abstract: Systems and methods for performing single-end line testing (SELT) are described. At least one embodiment includes a method for SELT to determine loop characteristics for a loop. The method for performing SELT comprises generating a test signal through a loop to be tested and receiving an echo response. The method further comprises subtracting predetermined near end echo response from the received echo to derive a far end echo response, performing time-dependent scaling on the far end echo response to compensate for loop attenuation, comparing the time-scaled far end echo response to a set of predefined templates, and providing an estimate of loop characteristics by identifying a matching template within the set of predefined templates, wherein the matching template contains information relating to loop characteristics comprising loop length and loop termination.

Abstract translation: 描述了执行单端线路测试（SELT）的系统和方法。 至少一个实施例包括用于SELT来确定循环的循环特性的方法。 用于执行SELT的方法包括通过要测试的环路产生测试信号并接收回波响应。 该方法还包括从接收到的回波中减去预定的近端回波响应以导出远端回波响应，对远端回波响应执行时间依赖的缩放以补偿环路衰减，将时间标度的远端回波响应与 一组预定义的模板，以及通过识别该组预定义模板内的匹配模板来提供循环特征的估计，其中该匹配模板包含与包括环路长度和环路终止的环路特性有关的信息。

公开(公告)号：US08767812B2

公开(公告)日：2014-07-01

申请号：US13081962

申请日：2011-04-07

Applicant: Lin Lin Li ,  Amitkumar Mahadevan

Inventor： Lin Lin Li ,  Amitkumar Mahadevan

IPC: H03H7/30

CPC classification number: H04L25/03044 ,  H04L25/022 ,  H04L2025/03681

Abstract: Various systems and methods are described for performing fractionally spaced time domain equalization (TEQ). One embodiment is a method implemented in a communication system for training a fractionally spaced time domain equalizer (TEQ). The method comprises performing an initialization phase, averaging a received signal in the system to reduce effects of noise in a channel, determining a channel estimate, and aligning an ideal reference signal with the received signal. The method further comprises updating a target response filter according to a non-integer multiple of a base sampling rate, determining an adaptation error based on useful information both inside and outside a Nyquist band of the TEQ, and updating the TEQ according to the adaptation error.

Abstract translation: 描述了用于执行分数间隔时域均衡（TEQ）的各种系统和方法。 一个实施例是在用于训练分数间隔的时域均衡器（TEQ）的通信系统中实现的方法。 该方法包括执行初始化阶段，对系统中的接收信号进行平均以减少信道中的噪声的影响，确定信道估计，以及使理想的参考信号与接收的信号对准。 该方法还包括根据基本采样率的非整数倍来更新目标响应滤波器，基于TEQ的奈奎斯特频带内部和外部的有用信息确定适配误差，以及根据自适应误差更新TEQ 。

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。

公开(公告)号：US07974181B2

公开(公告)日：2011-07-05

申请号：US12138731

申请日：2008-06-13

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

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

IPC: H04J11/00

CPC classification number: H04L27/2618

Abstract: Systems and methods for reducing the peak-to-average power 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 in the oversampled regime, using tones reserved for PAR reduction. A set of vectors corresponding to PAR tones is generated by processing out-of-phase symbols for each PAR tone to form a span matrix. The span matrix is used to find a best fit of a desired target signal to a time-domain compensation signal comprising only PAR tones.

Abstract translation: 用于降低发射机的峰均功率比（PAR）的系统和方法可以减少各种模拟组件所需的动态范围。 可以通过在过采样方案中应用时域补偿信号，使用保留给PAR减少的音调来减少PAR。 通过处理每个PAR色调的异相符号来生成对应于PAR色调的一组矢量以形成跨度矩阵。 跨度矩阵用于找到期望目标信号对仅包括PAR色调的时域补偿信号的最佳拟合。

公开(公告)号：US07957477B2

公开(公告)日：2011-06-07

申请号：US11845040

申请日：2007-08-25

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

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

IPC: H04L27/28

CPC classification number: H04B3/32 ,  H04L1/0042

Abstract: Systems and methods for off-diagonal MIMO precoders are described. At least one embodiment includes a method for precoding data for transmission in a discrete multi-tone (DMT) xDSL system to cancel self-induced far end crosstalk (self-FEXT) comprising: learning characteristics associated with a plurality of N users within the xDSL system to determine an initial off-diagonal multiple input multiple output (MIMO) precoder (ODMP) for a given tone frequency; and converging towards an optimum ODMP from the initial ODMP in order to cancel downstream self-FEXT for the plurality of N users, wherein the ODMP is represented as a zero diagonal matrix with only off-diagonal terms, and wherein the converging towards the optimum ODMP comprises: maximizing the channel capacity for the plurality of N users for the given tone frequency; and minimizing an increase in transmit power of the xDSL system relative to an original transmit power where a precoder is not active.

Abstract translation: 描述了非对角MIMO预编码器的系统和方法。 至少一个实施例包括用于预编码用于在离散多音（DMT）xDSL系统中传输的数据以消除自感应远端串扰（self-FEXT）的方法，包括：与xDSL内的多个N个用户相关联的学习特征 系统确定用于给定音频的初始非对角多输入多输出（MIMO）预编码器（ODMP）; 并从最初的ODMP收敛到最佳的ODMP，以消除多个N个用户的下游自身FEXT，其中ODMP被表示为只有非对角项的零对角矩阵，并且其中朝向最佳ODMP 包括：使给定音调频率的多个N个用户的信道容量最大化; 并且最小化xDSL系统相对于预编码器不活动的原始发射功率的发射功率的增加。

公开(公告)号：US20100278328A1

公开(公告)日：2010-11-04

申请号：US12431878

申请日：2009-04-29

Applicant: Amitkumar Mahadevan ,  Patrick Duvaut ,  Laurent Francis Alloin

Inventor： Amitkumar Mahadevan ,  Patrick Duvaut ,  Laurent Francis Alloin

IPC: H04B3/32

CPC classification number: H04B3/32

Abstract: Systems and methods are described for selecting tones for far-end crosstalk (FEXT) mitigation. In particular, systems and methods are described for performing far-end crosstalk (FEXT) mitigation within a digital subscriber line (xDSL) system. One embodiment is a method that comprises determining a first set of function values relating to a per-tone signal-to-noise ratio (SNR) for a user among a plurality of users for a number of tones, wherein the number of tones is less than or equal to a total number of tones available for transmission. The method further comprises estimating coefficients for performing FEXT mitigation for the number of tones, performing FEXT mitigation on the number of tones based on the estimated coefficients, and performing FEXT mitigation on a selected group of tones from among the number of tones, wherein the selected group of tones is less than or equal to the number tones.

Abstract translation: 描述了用于选择用于远端串扰（FEXT）减轻的音调的系统和方法。 特别地，描述了用于在数字用户线（xDSL）系统内执行远端串扰（FEXT）减轻的系统和方法。 一个实施例是一种方法，其包括确定与多个用户之间的用户对于多个音调的用户的每音调信噪比（SNR）有关的第一功能值集合，其中，音调数量较少 超过或等于可用于传输的总音数。 该方法还包括估计用于对音调数执行FEXT减轻的系数，基于估计的系数对音调数执行FEXT减轻，以及从所选择的音数中对所选择的音调组执行FEXT减轻，其中所选择的 一组音调小于或等于数字音。

公开(公告)号：US20100061437A1

公开(公告)日：2010-03-11

申请号：US12348565

申请日：2009-01-05

Applicant: Hemant Samdani ,  Kunal Raheja ,  Rahul Garg ,  Amitkumar Mahadevan ,  Patrick Duvaut

Inventor： Hemant Samdani ,  Kunal Raheja ,  Rahul Garg ,  Amitkumar Mahadevan ,  Patrick Duvaut

IPC: H04B17/00

CPC classification number: H04B3/46

Abstract: Impulse noise from nearby or intense electrical sources can disrupt communications over digital subscriber lines (DSL). The characterization of the nature, timing and length of impulse noise sources present on a DSL loop is a critical first step in mitigating the effect of impulse noise on DSL communications. DSL standards provide histograms for impulse length and inter-arrival time of impulses. These histograms can be used to derive the nature, maximum frequency and other statistics related to impulse noise on a DSL line.

Abstract translation: 来自附近或强电场的脉冲噪声可能会扰乱通过数字用户线路（DSL）的通信。 存在于DSL环路上的脉冲噪声源的性质，时间和长度的表征是减轻脉冲噪声对DSL通信的影响的关键的第一步。 DSL标准提供脉冲长度和脉冲到达间隔时间的直方图。 这些直方图可用于导出与DSL线路上的脉冲噪声有关的性质，最大频率和其他统计。