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    Dual-loop automatic frequency control for wireless communication
    1.
    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
    2.
    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。

    Automatic frequency control for a wireless communication system with multiple subcarriers
    3.
    发明申请
    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：US20060215778A1

    公开(公告)日：2006-09-28

    申请号：US11372931

    申请日：2006-03-09

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

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

    IPC分类号： H04K1/10

    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，选择接收到的OFDM符号的可变数目的样本，以用于频率误差估计。

    Coarse timing/frame acquisition of OFDM system using time division multiplexed pilot symbol
    4.
    发明授权
    Coarse timing/frame acquisition of OFDM system using time division multiplexed pilot symbol 失效
    使用时分复用导频符号的OFDM系统的粗时序/帧采集

    公开(公告)号：US07756005B2

    公开(公告)日：2010-07-13

    申请号：US11371039

    申请日：2006-03-08

    申请人： Vinay Murthy ,  Alok Kumar Gupta

    发明人： Vinay Murthy ,  Alok Kumar Gupta

    IPC分类号： H04J11/00

    CPC分类号： H04L27/2656 ,  H04L27/2675

    摘要： Systems and methods are provided for processing Time Domain Multiplexing (TDM) symbols via delayed correlation in the time domain. In one embodiment, a method is provided for determining synchronization information in an Orthogonal Frequency Division Multiplexing (OFDM) broadcast. The method includes employing a time domain correlation to detect the start of an OFDM super frame and utilizing the time domain correlation to synchronize a receiver to the carrier frequency of the OFDM signal.

    摘要翻译： 提供了系统和方法，用于通过时域中的延迟相关来处理时域多路复用（TDM）符号。 在一个实施例中，提供了一种用于在正交频分复用（OFDM）广播中确定同步信息的方法。 该方法包括采用时域相关性来检测OFDM超帧的开始，并利用时域相关性使接收机与OFDM信号的载波频率同步。

    Coarse timing/frame acquisition in OFDM system using time division multiplexed pilot symbol
    5.
    发明申请
    Coarse timing/frame acquisition in OFDM system using time division multiplexed pilot symbol 失效
    使用时分多路复用导频符号的OFDM系统中的粗定时/帧采集

    公开(公告)号：US20060215538A1

    公开(公告)日：2006-09-28

    申请号：US11371039

    申请日：2006-03-08

    申请人： Vinay Murthy ,  Alok Kumar Gupta

    发明人： Vinay Murthy ,  Alok Kumar Gupta

    IPC分类号： H04J11/00 ,  H04J3/06

    CPC分类号： H04L27/2656 ,  H04L27/2675

    摘要： Systems and methods are provided for processing Time Domain Multiplexing (TDM) symbols via delayed correlation in the time domain. In one embodiment, a method is provided for determining synchronization information in an Orthogonal Frequency Division Multiplexing (OFDM) broadcast. The method includes employing a time domain correlation to detect the start of an OFDM super frame and utilizing the time domain correlation to synchronize a receiver to the carrier frequency of the OFDM signal.

    摘要翻译： 提供了系统和方法，用于通过时域中的延迟相关来处理时域多路复用（TDM）符号。 在一个实施例中，提供了一种用于在正交频分复用（OFDM）广播中确定同步信息的方法。 该方法包括采用时域相关性来检测OFDM超帧的开始，并利用时域相关性使接收机与OFDM信号的载波频率同步。

    Methods and apparatus for frequency tracking of a received signal
    6.
    发明授权
    Methods and apparatus for frequency tracking of a received signal 有权
    接收信号频率跟踪的方法和装置

    公开(公告)号：US07746963B2

    公开(公告)日：2010-06-29

    申请号：US11557921

    申请日：2006-11-08

    申请人： Seong Taek Chung ,  Krishna Kiran Mukkavilli ,  Vinay Murthy ,  Tao Tian

    发明人： Seong Taek Chung ,  Krishna Kiran Mukkavilli ,  Vinay Murthy ,  Tao Tian

    IPC分类号： H04L27/00

    CPC分类号： H04L27/2657 ,  H04L27/2675

    摘要： Methods and apparatus for frequency tracking of a received signal. In an aspect, a method is provided wherein the received signal comprises one or more symbols having a periodic structure. The method comprises receiving a plurality of samples of a selected symbol that comprises pilot signals scrambled with data and determining a window size and a periodicity factor. The method also comprises accumulating a correlation between samples in a first window and samples in a second window to produce an accumulated correlation value, wherein the first and second windows have a size and a separation based on the window size and the periodicity factor, respectively, and deriving a frequency error estimate based on the accumulated correlation value.

    摘要翻译： 接收信号频率跟踪的方法和装置。 在一方面，提供了一种方法，其中接收的信号包括具有周期性结构的一个或多个符号。 该方法包括：接收包含由数据加扰的导频信号和确定窗口大小和周期因子的所选符号的多个样本。 该方法还包括在第一窗口中累积样本之间的相关性并在第二窗口中采样以产生累加的相关值，其中第一和第二窗口分别具有基于窗口大小和周期性因子的大小和间隔， 以及基于所累积的相关值导出频率误差估计。