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    Frequency error estimation and frame synchronization in an OFDM system
    3.
    发明授权
    Frequency error estimation and frame synchronization in an OFDM system 失效
    OFDM系统中的频率误差估计和帧同步

    公开(公告)号：US07746760B2

    公开(公告)日：2010-06-29

    申请号：US10754796

    申请日：2004-01-08

    申请人： Rajiv Vijayan ,  Alok Kumar Gupta ,  Raghuraman Krishnamoorthi

    发明人： Rajiv Vijayan ,  Alok Kumar Gupta ,  Raghuraman Krishnamoorthi

    IPC分类号： H04J11/00 ,  H04J3/06

    CPC分类号： H04L27/2656 ,  H04L27/2657 ,  H04L27/2675

    摘要： Frequency error estimation and frame synchronization are performed at a receiver in an OFDM system based on a metric that is indicative of detected pilot power. The metric may be defined based on cross-correlation between two received symbols obtained in two OFDM symbol periods. For frequency error estimation, a metric value is computed for each of multiple hypothesized frequency errors. The hypothesized frequency error for the metric value with the largest magnitude is provided as the estimated frequency error. For frame synchronization, a correlation value is obtained for each OFDM symbol period by correlating metric values obtained for NC (e.g., most recent) OFDM symbol periods with NC expected values. The expected values are computed in a manner consistent with the manner in which the metric values are computed. Peak detection is performed on the correlation values obtained for different OFDM symbol periods to determine frame synchronization.

    摘要翻译： 基于指示检测到的导频功率的度量，在OFDM系统中的接收机处执行频率误差估计和帧同步。 可以基于在两个OFDM符号周期中获得的两个接收符号之间的互相关来定义度量。 对于频率误差估计，针对多个假设的频率误差中的每一个计算度量值。 提供具有最大幅度的度量值的假设频率误差作为估计的频率误差。 对于帧同步，通过将为NC（例如，最近的）OFDM符号周期获得的度量值与NC预期值相关联，获得每个OFDM符号周期的相关值。 以与计算度量值的方式一致的方式计算期望值。 对针对不同的OFDM符号周期获得的相关值执行峰值检测以确定帧同步。

    Dual-loop automatic frequency control for wireless communication
    4.
    发明授权
    Dual-loop automatic frequency control for wireless communication 有权
    双回路自动频率控制用于无线通信

    公开(公告)号：US08401503B2

    公开(公告)日：2013-03-19

    申请号：US11358996

    申请日：2006-02-21

    申请人： Seong Taek Chung ,  Vinay Murthy ,  Alok Kumar Gupta ,  Fuyun Ling

    发明人： Seong Taek Chung ,  Vinay Murthy ,  Alok Kumar Gupta ,  Fuyun Ling

    IPC分类号： H04B1/18

    CPC分类号： H03J7/04 ,  H03J1/0083

    摘要： Techniques for performing frequency control using dual-loop automatic frequency control (AFC) are described. The dual-loop AFC includes an inner loop that corrects short-term frequency variations (e.g., due to Doppler effect) and an outer loop that corrects long-term frequency variations (e.g., due to component tolerances and temperature variations). In one design, a first inner loop is implemented for frequency control of a first system (e.g., a broadcast system), a second inner loop is implemented for frequency control of a second system (e.g., a cellular system), and at least one outer loop is implemented for adjusting a reference frequency used to receive signals from the first and second systems. Each inner loop estimates and corrects the frequency error in an input signal for the associated system and may be enabled when receiving the input signal from the system. The reference frequency may be used for frequency downconversion, sampling and/or other purposes.

    摘要翻译： 描述了使用双回路自动频率控制（AFC）进行频率控制的技术。 双回路AFC包括校正短期频率变化（例如，由于多普勒效应引起的）的内部循环和校正长期频率变化（例如由于部件公差和温度变化）的外部回路。 在一种设计中，为第一系统（例如，广播系统）的频率控制实现第一内环，为第二系统（例如，蜂窝系统）的频率控制实现第二内环，并且至少一个 实现外部环路，用于调整用于从第一和第二系统接收信号的参考频率。 每个内循环估计和校正相关系统的输入信号中的频率误差，并且当从系统接收输入信号时可以使能频率误差。 参考频率可用于下变频，采样和/或其他目的。

    Automatic frequency control for a wireless communication system with multiple subcarriers
    5.
    发明授权
    Automatic frequency control for a wireless communication system with multiple subcarriers 有权
    具有多个子载波的无线通信系统的自动频率控制

    公开(公告)号：US08009775B2

    公开(公告)日：2011-08-30

    申请号：US11372931

    申请日：2006-03-09

    申请人： Vinay Murthy ,  Alok Kumar Gupta ,  Seong Taek Chung ,  Fuyun Ling

    发明人： Vinay Murthy ,  Alok Kumar Gupta ,  Seong Taek Chung ,  Fuyun Ling

    IPC分类号： H04L27/06 ,  H04L7/00 ,  H04L27/00

    CPC分类号： G06F1/0353 ,  H04L5/0007 ,  H04L5/0048 ,  H04L27/2659 ,  H04L27/266 ,  H04L27/2662 ,  H04L27/2675 ,  H04L27/2678

    摘要： Techniques for performing frequency control in an OFDM system are described. In one aspect, frequency acquisition is performed based on a received pilot, and frequency tracking is performed based on received OFDM symbols. For frequency acquisition, an initial frequency error estimate may be derived based on the received pilot, and an automatic frequency control (AFC) loop may be initialized with the initial frequency error estimate. For frequency tracking, a frequency error estimate may be derived for each received OFDM symbol, and the AFC loop may be updated with the frequency error estimate. Frequency error in input samples is corrected by the AFC loop with the initial frequency error estimate as well as the frequency error estimate for each received OFDM symbol. In another aspect, a variable number of samples of a received OFDM symbol are selected, e.g., based on the received OFDM symbol timing, for use for frequency error estimation.

    摘要翻译： 描述在OFDM系统中执行频率控制的技术。 在一个方面，基于接收到的导频执行频率采集，并且基于接收的OFDM符号执行频率跟踪。 对于频率获取，可以基于接收到的导频来导出初始频率误差估计，并且可以利用初始频率误差估计来初始化自动频率控制（AFC）循环。 对于频率跟踪，可以针对每个接收的OFDM符号导出频率误差估计，并且可以用频率误差估计来更新AFC循环。 通过具有初始频率误差估计的AFC回路以及每个接收的OFDM符号的频率误差估计来校正输入采样中的频率误差。 在另一方面，例如基于所接收的OFDM符号定时，选择接收的OFDM符号的可变数目的样本，以用于频率误差估计。

    Coarse timing estimation system and methodology for wireless symbols
    6.
    发明授权
    Coarse timing estimation system and methodology for wireless symbols 有权
    无线符号的粗定时估计系统和方法

    公开(公告)号：US07860193B2

    公开(公告)日：2010-12-28

    申请号：US11020411

    申请日：2004-12-22

    申请人： Alok Kumar Gupta

    发明人： Alok Kumar Gupta

    IPC分类号： H04L27/06

    CPC分类号： H04L27/2665 ,  H04L27/2607 ,  H04L27/2662

    摘要： A system that facilitates obtaining a coarse estimation of a boundary of symbol with respect to time comprises a peak detector that detects a peak energy of an energy distribution output by a correlator, and an estimating component that adaptively estimates a boundary of the symbol based as a function of the detected peak energy. A parameter defined as a function of the magnitude to create a threshold value, the estimate obtained as a function of a comparison of the threshold with the energy distribution.

    摘要翻译： 有助于获得关于时间的符号边界的粗略估计的系统包括检测由相关器输出的能量分布的峰值能量的峰值检测器，以及估计部件，其自适应地将符号的边界估计为 检测到的峰值能量的功能。 定义为产生阈值的幅度的函数的参数，作为阈值与能量分布的比较的函数获得的估计。

    Heat treatment process for aluminum alloy sheet
    7.
    再颁专利
    Heat treatment process for aluminum alloy sheet 失效
    铝合金板材热处理工艺

    公开(公告)号：USRE36692E

    公开(公告)日：2000-05-16

    申请号：US113619

    申请日：1998-07-10

    申请人： Alok Kumar Gupta ,  Michael J. Wheeler ,  Michael Jackson Bull ,  Pierre Henri Marois

    发明人： Alok Kumar Gupta ,  Michael J. Wheeler ,  Michael Jackson Bull ,  Pierre Henri Marois

    IPC分类号： C22F1/00 ,  C22C21/02 ,  C22C21/06 ,  C22C21/08 ,  C22C21/14 ,  C22C21/16 ,  C22F1/04 ,  C22F1/043 ,  C22F1/05 ,  C22F1/057

    CPC分类号： C22F1/043 ,  C22C21/02 ,  C22C21/08 ,  C22C21/14 ,  C22C21/16 ,  C22F1/04 ,  C22F1/05 ,  C22F1/057

    摘要： A process of producing solution heat treated aluminum alloy sheet material comprises subjecting hot- or cold-rolled aluminum alloy sheet to solution heat treatment followed by quenching and, before substantial age hardening has taken place, subjecting the alloy sheet material to one or more subsequent heat treatments involving heating the material to a peak temperature in the range of 100.degree. to 300.degree. C. (preferably 130.degree.-270.degree. C.), holding the material at the peak temperature for a period of time less than about 1 minute, and cooling the alloy from the peak temperature to a temperature of 85.degree. C. or less. The sheet material treated in this way can be used for automotive panels and has good a good "paint bake response", i.e. an increase in yield strength from the T4 temper to the T8X temper upon painting and baking of the panels.

    摘要翻译： 制备固溶热处理的铝合金板材的方法包括将热轧或冷轧铝合金板材进行固溶热处理，然后淬火，并且在大量时效硬化之前，对合金板材进行一个或多个随后的热处理 包括将材料加热到100℃至300℃（优选130℃-270℃）的峰值温度的处理，将材料保持在峰值温度下时间小于约1分钟，以及 将合金从峰值温度冷却至85℃以下的温度。 以这种方式处理的片材可以用于汽车面板，并且具有良好的“烤漆响应”，即在面漆的涂漆和烘烤时从T4回火到T8X回火的屈服强度的增加。

    Heat treatment process for aluminum alloy sheet
    9.
    发明授权
    Heat treatment process for aluminum alloy sheet 失效
    铝合金板材热处理工艺

    公开(公告)号：US5728241A

    公开(公告)日：1998-03-17

    申请号：US764983

    申请日：1996-12-13

    申请人： Alok Kumar Gupta ,  Michael J. Wheeler ,  Michael J. Bull ,  Pierre H. Marois

    发明人： Alok Kumar Gupta ,  Michael J. Wheeler ,  Michael J. Bull ,  Pierre H. Marois

    IPC分类号： C22F1/00 ,  C22C21/02 ,  C22C21/06 ,  C22C21/08 ,  C22C21/14 ,  C22C21/16 ,  C22F1/04 ,  C22F1/043 ,  C22F1/05 ,  C22F1/057

    CPC分类号： C22F1/043 ,  C22C21/02 ,  C22C21/08 ,  C22C21/14 ,  C22C21/16 ,  C22F1/04 ,  C22F1/05 ,  C22F1/057

    摘要： A process of producing solution heat treated aluminum alloy sheet material comprises subjecting hot- or cold-rolled aluminum alloy sheet to solution heat treatment followed by quenching and, before substantial age hardening has taken place, subjecting the alloy sheet material to one or more subsequent heat treatments involving heating the material to a peak temperature in the range of 100.degree. to 300.degree. C. (preferably 130.degree.-270.degree. C.), holding the material at the peak temperature for a period of time less than about 1 minute, and cooling the alloy from the peak temperature to a temperature of 85.degree. C. or less. The sheet material treated in this way can by used for automotive panels and has good a good "paint bake response", i.e. an increase in yield strength from the T4 temper to the T8X temper upon painting and baking of the panels.

    摘要翻译： 制备固溶热处理的铝合金板材的方法包括将热轧或冷轧铝合金板材进行固溶热处理，然后淬火，并且在大量时效硬化之前，对合金板材进行一个或多个随后的热处理 包括将材料加热到100℃至300℃（优选130℃-270℃）的峰值温度的处理，将材料保持在峰值温度下时间小于约1分钟，以及 将合金从峰值温度冷却至85℃以下的温度。 以这种方式处理的片材可以用于汽车面板，并且具有良好的“烤漆响应”，即在面漆的涂漆和烘烤时从T4回火到T8X回火的屈服强度的增加。

    Frame synchronization and initial symbol timing acquisition system and method
    10.
    发明授权
    Frame synchronization and initial symbol timing acquisition system and method 失效
    帧同步和初始符号定时采集系统及方法

    公开(公告)号：US08433005B2

    公开(公告)日：2013-04-30

    申请号：US11020413

    申请日：2004-12-22

    申请人： Alok Kumar Gupta

    发明人： Alok Kumar Gupta

    IPC分类号： H04L27/06 ,  H04L7/04 ,  H04J3/06

    CPC分类号： H04L27/2656 ,  H04L27/2657 ,  H04L27/2662 ,  H04L27/2675

    摘要： A robust initial frame detection and symbol synchronization system and methodology are provided. In particular, a first pilot is employed in conjunction with three acquisition stages. In the first stage, an attempt is made to observe the leading edge of the correlation curve associated with the first pilot symbol. In the second stage, a determination is made as to whether a leading edge was detected in the first stage by attempting to observe a flat portion and/or trailing edge of the correlation curve. Furthermore, during this second stage, a frequency loop can be updated to account for frequency offset. The third stage is for observing the trailing edge of the curve if it was not already observed in stage two. Upon detection and confirmation of receipt of the first pilot, a second pilot can subsequently be employed to acquire fine symbol timing.

    摘要翻译： 提供了鲁棒的初始帧检测和符号同步系统和方法。 特别地，与三个采集阶段结合使用第一飞行员。 在第一阶段，尝试观察与第一导频符号相关联的相关曲线的前沿。 在第二阶段中，通过尝试观察相关曲线的平坦部分和/或后缘来确定在第一阶段中是否检测到前缘。 此外，在该第二阶段期间，可以更新频率环以考虑频率偏移。 如果在第二阶段没有观察到，则第三阶段用于观察曲线的后缘。 在检测并确认接收到第一导频时，随后可以采用第二导频来获取精细符号定时。