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    Adaptive time-filtering for channel estimation in OFDM system
    11.
    发明授权
    Adaptive time-filtering for channel estimation in OFDM system 有权
    OFDM系统中信道估计的自适应时间滤波

    公开(公告)号：US08442160B2

    公开(公告)日：2013-05-14

    申请号：US12939118

    申请日：2010-11-03

    Applicant: Linbo Li ,  Ashok Mantravadi ,  Fuyun Ling ,  Krishna Kiran Mukkavilli

    Inventor： Linbo Li ,  Ashok Mantravadi ,  Fuyun Ling ,  Krishna Kiran Mukkavilli

    IPC: H04L27/06

    CPC classification number: H04L25/0232 ,  H04L25/022

    Abstract: Time filtering channel estimates in a wireless communication system, such as an Orthogonal Frequency Division Multiplex (OFDM) system, can be used to improve the quality of channel estimates. The characteristics of an optimal channel estimate time filter can depend on the manner in which the channel estimate is determined as well as the time correlation of channel estimates. A receiver can implement an adaptive time filter for channel estimates in which the time filter response can vary based on channel estimate parameters. The channel estimate parameters can include the manner of determining channel estimates, a time correlation of channel estimates, and an estimated Doppler frequency. The time filter response can be varied continuously over a range of responses or can be varied discretely over a predetermined number of time filter responses.

    Abstract translation: 在诸如正交频分复用（OFDM）系统的无线通信系统中的时间滤波信道估计可以用于提高信道估计的质量。 最优信道估计时间滤波器的特征可以取决于信道估计的方式以及信道估计的时间相关性。 接收机可以实现用于信道估计的自适应时间滤波器，其中时间滤波器响应可以基于信道估计参数而变化。 信道估计参数可以包括确定信道估计的方式，信道估计的时间相关性和估计的多普勒频率。 时间滤波器响应可以在响应范围内连续变化，或者可以在预定数量的时间滤波器响应上离散变化。

    Timing corrections in a multi carrier system and propagation to a channel estimation time filter
    12.
    发明授权
    Timing corrections in a multi carrier system and propagation to a channel estimation time filter 有权
    多载波系统中的定时校正和传播到信道估计时间滤波器

    公开(公告)号：US08428001B2

    公开(公告)日：2013-04-23

    申请号：US11373764

    申请日：2006-03-09

    Applicant: Bojan Vrcelj ,  Ashok Mantravadi ,  Fuyun Ling ,  Krishna Kiran Mukkavilli

    Inventor： Bojan Vrcelj ,  Ashok Mantravadi ,  Fuyun Ling ,  Krishna Kiran Mukkavilli

    IPC: H04B7/212

    CPC classification number: H04L25/0232 ,  H04L25/0212 ,  H04L25/0224 ,  H04L25/025 ,  H04L27/2662 ,  H04L27/2665

    Abstract: Systems and methods are provided for determining and applying timing corrections in a digital communications system. In an aspect, a timing correction method is provided for a multi-carrier system. This includes aligning two or more symbols with respect to each other from a symbol subset in order to account for timing differences between the symbols. The symbol alignment is first carried out to generate channel estimates for data demodulation. The channel estimates, thus generated, along with the timing alignment information are in turn used for determining timing corrections-to be applied to future symbols.

    Abstract translation: 提供了用于在数字通信系统中确定和应用定时校正的系统和方法。 在一方面，为多载波系统提供定时校正方法。 这包括从符号子集彼此对准两个或更多个符号，以便考虑符号之间的时序差异。 首先执行符号对齐以产生用于数据解调的信道估计。 由此生成的信道估计以及定时对准信息又用于确定定时校正，以应用于将来的符号。

    METHODS AND APPARATUS FOR TIME TRACKING USING ASSITANCE FROM TDM PILOTS IN A COMMUNICATION NETWORK
    13.
    发明申请
    METHODS AND APPARATUS FOR TIME TRACKING USING ASSITANCE FROM TDM PILOTS IN A COMMUNICATION NETWORK 有权
    在通信网络中使用TDM PILOTS的资产进行时间跟踪的方法和装置

    公开(公告)号：US20110116396A1

    公开(公告)日：2011-05-19

    申请号：US12917789

    申请日：2010-11-02

    Applicant: Bojan Vrcelj ,  Ashok Mantravadi ,  Krishna Kiran Mukkavilli ,  Raghuraman Krishnamoorthi

    Inventor： Bojan Vrcelj ,  Ashok Mantravadi ,  Krishna Kiran Mukkavilli ,  Raghuraman Krishnamoorthi

    IPC: H04J3/14 ,  H04L12/26

    CPC classification number: H04L27/2662 ,  H04L25/0216 ,  H04L25/0224 ,  H04L27/2675 ,  H04L27/2695

    Abstract: Methods and apparatus for time tracking using assistance from TDM pilots in a communication network. In an aspect, a method is provided for time tracking in a device operating on a communication network, wherein the device performs a time tracking algorithm. The method includes determining a delay spread, and modifying at least one parameter used by the time tracking algorithm based on the delay spread. In another aspect, an apparatus is provided for time tracking in a device operating on a communication network, wherein the device performs a time tracking algorithm. The apparatus includes computation logic for determining a delay spread, and control logic for modifying at least one parameter used by the time tracking algorithm based on the delay spread.

    Abstract translation: 在通信网络中使用TDM导频协助进行时间跟踪的方法和装置。 在一方面，提供了一种用于在通信网络上操作的设备中进行时间跟踪的方法，其中该设备执行时间跟踪算法。 该方法包括确定延迟扩展，以及基于延迟扩展修改由时间跟踪算法使用的至少一个参数。 在另一方面，提供了一种用于在通信网络上操作的设备中进行时间跟踪的设备，其中该设备执行时间跟踪算法。 该装置包括用于确定延迟扩展的计算逻辑，以及用于基于延迟扩展修改由时间跟踪算法使用的至少一个参数的控制逻辑。

    Methods and apparatus for noise estimation in a communication system
    17.
    发明授权
    Methods and apparatus for noise estimation in a communication system 有权
    通信系统中噪声估计的方法和装置

    公开(公告)号：US07724849B2

    公开(公告)日：2010-05-25

    申请号：US11516910

    申请日：2006-09-06

    Applicant: Fuyun Ling ,  Krishna Kiran Mukkavilli ,  Gordon Kent Walker

    Inventor： Fuyun Ling ,  Krishna Kiran Mukkavilli ,  Gordon Kent Walker

    IPC: H03D1/04

    CPC classification number: H04L1/20 ,  H04L27/2602 ,  H04L27/2647

    Abstract: Methods and apparatus for noise estimation in a communication system. In an aspect, a method for noise and interference estimation is provided. The method includes identifying one or more unmodulated subcarriers in a received waveform, processing the one or more unmodulated subcarriers to produce a demodulated output, and determining a noise variance based on the demodulated output. In another aspect, an apparatus for providing a noise and interference estimation is provided. The apparatus includes selection logic configured to identify one or more unmodulated subcarriers in a received waveform, a processor configured to demodulate the one or more unmodulated subcarriers to produce a demodulated output, and variance determination logic configured to determine a noise variance based on the demodulated output.

    Abstract translation: 通信系统中噪声估计的方法和装置。 在一方面，提供了一种用于噪声和干扰估计的方法。 该方法包括识别接收波形中的一个或多个未调制副载波，处理一个或多个未调制副载波以产生解调输出，以及基于解调输出确定噪声方差。 另一方面，提供了一种用于提供噪声和干扰估计的装置。 所述设备包括被配置为识别接收波形中的一个或多个未调制子载波的选择逻辑，被配置为对所述一个或多个未调制子载波进行解调以产生解调输出的处理器，以及配置为基于解调输出来确定噪声方差的方差确定逻辑 。

    METHODS AND APPARATUS FOR ADAPTING CHANNEL ESTIMATION IN A COMMUNICATION SYSTEM
    18.
    发明申请
    METHODS AND APPARATUS FOR ADAPTING CHANNEL ESTIMATION IN A COMMUNICATION SYSTEM 有权
    在通信系统中适应通道估计的方法和装置

    公开(公告)号：US20090245333A1

    公开(公告)日：2009-10-01

    申请号：US12396144

    申请日：2009-03-02

    Applicant: Raghuraman Krishnamoorthi ,  Krishna Kiran Mukkavilli ,  Ashok Mantravadi

    Inventor： Raghuraman Krishnamoorthi ,  Krishna Kiran Mukkavilli ,  Ashok Mantravadi

    IPC: H04B1/38

    CPC classification number: H04L25/0202

    Abstract: Methods and apparatus for adapting a channel estimation scheme in a transceiver in a communication system are disclosed to adapt channel estimation to the transceiver environment, particularly for high Doppler environments. The disclosed methods and apparatus effect determination of an estimate of a power delay profile of a channel or a time correlation of the channel, or both. A channel estimation scheme is then determined based on at least one of the determined power delay profile and time correlation of the channel. By basing determination of a channel estimation scheme on the power delay profile and/or the time correlation of the channel, the channel estimation scheme is adapted to the particular environment of the transceiver by accounting for the delay spread of the channel and/or the speed of the transceiver.

    Abstract translation: 公开了用于在通信系统中的收发器中适配信道估计方案的方法和装置，以使信道估计适应收发器环境，特别是对于高多普勒环境。 所公开的方法和装置效应确定信道的功率延迟分布的估计或信道的时间相关性，或两者。 然后基于所确定的功率延迟分布和信道的时间相关性中的至少一个来确定信道估计方案。 通过基于信道估计方案对功率延迟分布的确定和/或信道的时间相关性，信道估计方案通过考虑信道的延迟扩展和/或速度来适应收发器的特定环境 的收发器。

    STAGGEREDPILOT TRANSMISSION FOR CHANNEL ESTIMATION AND TIME TRACKING
    19.
    发明申请
    STAGGEREDPILOT TRANSMISSION FOR CHANNEL ESTIMATION AND TIME TRACKING 有权
    STAGGEREDPILOT传输信道估计和时间跟踪

    公开(公告)号：US20090129511A1

    公开(公告)日：2009-05-21

    申请号：US12254680

    申请日：2008-10-20

    Applicant: Rajiv Vijayan ,  Ashok Mantravadi ,  Krishna Kiran Mukkavilli

    Inventor： Rajiv Vijayan ,  Ashok Mantravadi ,  Krishna Kiran Mukkavilli

    IPC: H04L27/06

    CPC classification number: H04L25/022 ,  H04L5/0048 ,  H04L23/02 ,  H04L25/0212 ,  H04L25/0228 ,  H04L27/2662 ,  H04L27/2695

    Abstract: To allow a receiving entity to derive a longer channel estimate while limiting overhead, a transmitting entity transmits a pilot on different groups of subbands in different time intervals. N subbands in the system are arranged into M non-overlapping groups. Each group includes P=N/M subbands that are uniformly distributed across the N subbands. The transmitting entity transmits the pilot on a different subband group in each time interval, and selects all M subband groups in M time intervals based on a pilot staggering pattern. The receiving entity derives (1) an initial impulse response estimate with P channel taps based on the pilot received on one subband group and (2) two longer impulse response estimates with different lengths used for data detection and time tracking. Each longer impulse response estimate may be derived by filtering initial impulse response estimates for a sufficient number of subband groups using a time-domain filter.

    Abstract translation: 为了允许接收实体在限制开销的同时导出更长的信道估计，发送实体以不同的时间间隔在不同的子带组上发送导频。 系统中的N个子带被布置成M个非重叠组。 每组包括均匀分布在N个子带上的P = N / M个子带。 发送实体在每个时间间隔中在不同子带组上发送导频，并且基于导频交错模式以M个时间间隔选择所有M个子带组。 接收实体基于在一个子带组上接收到的导频导出（1）具有P信道抽头的初始脉冲响应估计，以及（2）用于数据检测和时间跟踪的两个具有不同长度的较长脉冲响应估计。 可以通过使用时域滤波器对足够数量的子带组的初始脉冲响应估计进行滤波来导出更长的脉冲响应估计。

    Staggered pilot transmission for channel estimation and time tracking
    20.
    发明授权
    Staggered pilot transmission for channel estimation and time tracking 有权
    用于信道估计和时间跟踪的交错导频传输

    公开(公告)号：US07457231B2

    公开(公告)日：2008-11-25

    申请号：US10926884

    申请日：2004-08-25

    Applicant: Rajiv Vijayan ,  Ashok Mantravadi ,  Krishna Kiran Mukkavilli

    Inventor： Rajiv Vijayan ,  Ashok Mantravadi ,  Krishna Kiran Mukkavilli

    IPC: H04J11/00

    CPC classification number: H04L25/022 ,  H04L5/0048 ,  H04L23/02 ,  H04L25/0212 ,  H04L25/0228 ,  H04L27/2662 ,  H04L27/2695

    Abstract: To allow a receiving entity to derive a longer channel estimate while limiting overhead, a transmitting entity transmits a pilot on different groups of subbands in different time intervals. N subbands in the system are arranged into M non-overlapping groups. Each group includes P=N/M subbands that are uniformly distributed across the N subbands. The transmitting entity transmits the pilot on a different subband group in each time interval, and selects all M subband groups in M time intervals based on a pilot staggering pattern. The receiving entity derives (1) an initial impulse response estimate with P channel taps based on the pilot received on one subband group and (2) two longer impulse response estimates with different lengths used for data detection and time tracking. Each longer impulse response estimate may be derived by filtering initial impulse response estimates for a sufficient number of subband groups using a time-domain filter.

    Abstract translation: 为了允许接收实体在限制开销的同时导出较长的信道估计，发送实体以不同的时间间隔在不同的子带组上发送导频。 系统中的N个子带被布置成M个非重叠组。 每组包括均匀分布在N个子带上的P = N / M个子带。 发送实体在每个时间间隔中在不同子带组上发送导频，并且基于导频交错模式以M个时间间隔选择所有M个子带组。 接收实体基于在一个子带组上接收到的导频导出（1）具有P信道抽头的初始脉冲响应估计，以及（2）用于数据检测和时间跟踪的两个具有不同长度的较长脉冲响应估计。 可以通过使用时域滤波器对足够数量的子带组的初始脉冲响应估计进行滤波来导出更长的脉冲响应估计。

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