公开(公告)号：US08045636B1

公开(公告)日：2011-10-25

申请号：US12057221

申请日：2008-03-27

申请人： Jungwon Lee ,  Qing Zhao ,  Jihwan P. Choi

发明人： Jungwon Lee ,  Qing Zhao ,  Jihwan P. Choi

IPC分类号： H04L5/12 ,  H04L23/02

CPC分类号： H04L27/2656 ,  H04L5/0048 ,  H04L27/2613 ,  H04L27/2675

摘要： Autocorrelation algorithms are employed in systems and methods to detect preamble symbols for frame synchronization in WiMAX (Worldwide Interoperability for Microwave Access) or OFDMA (Orthogonal Frequency Division Multiple Access) systems. An ML (“Maximum Likelihood”) estimator estimates segment index and frame timing information for an ideal signal scenario. When using the ML estimator, a received time domain signal is sampled. Groups of samples are formed, and the group is further divided into a plurality of portions. Then, an autocorrelation between time domain samples of each portion results in a maximum value which indicates the start of a preamble of the time domain signal. Frame synchronization can then be performed. In other transmission scenarios, the algorithm is modified to use modified estimators of the preamble symbol location. When using the modified estimators, less than all of the portions of samples are compared to one another to find a maximum value.

摘要翻译： 在WiMAX（全球微波接入互操作性）或OFDMA（正交频分多址）系统中用于检测用于帧同步的前同码符的系统和方法中采用自相关算法。 ML（“最大似然”）估计器估计理想信号场景的片段索引和帧定时信息。 当使用ML估计器时，对接收到的时域信号进行采样。 形成一组样品，并将该组进一步分成多个部分。 然后，每个部分的时域样本之间的自相关产生指示时域信号的前导码开始的最大值。 然后可以执行帧同步。 在其他传输场景中，修改算法以使用前导符号位置的修改估计器。 当使用修改后的估计量时，将少于样本的全部部分相互比较以找到最大值。

公开(公告)号：US08582692B1

公开(公告)日：2013-11-12

申请号：US13613212

申请日：2012-09-13

申请人： Qing Zhao ,  Souvik Dihidar ,  Leilei Song ,  Jungwon Lee

发明人： Qing Zhao ,  Souvik Dihidar ,  Leilei Song ,  Jungwon Lee

IPC分类号： H04L25/06

CPC分类号： H04L27/2647 ,  H04L25/06

摘要： In accordance with the teachings described herein, systems and methods are provided for calibrating DC offset in a receiver. A DC calibration circuit may be used that is configured to remove DC offset from a digital multi-carrier modulated (MCM) signal that includes a sequence of MCM symbols. The DC calibration circuit may include an accumulator and a compensator. The accumulator may be used to determine an estimated DC offset of a current MCM symbol in the sequence of MCM symbols. The compensator may be used to remove the estimated DC offset from a next MCM symbol in the sequence of MCM symbols. The accumulator may also be used to receive a plurality of digital samples that comprise the current MCM symbol and to determine the estimated DC offset by calculating an average of the plurality of digital samples.

摘要翻译： 根据本文所述的教导，提供了用于校准接收机中的DC偏移的系统和方法。 可以使用DC校准电路，其被配置为从包括MCM符号序列的数字多载波调制（MCM）信号中去除DC偏移。 DC校准电路可以包括蓄电池和补偿器。 可以使用累加器来确定MCM符号序列中的当前MCM符号的估计DC偏移。 补偿器可以用于从MCM符号序列中的下一个MCM符号中去除估计的DC偏移。 累加器还可以用于接收包括当前MCM符号的多个数字样本，并且通过计算多个数字样本的平均值来确定估计的DC偏移。

公开(公告)号：US08433003B1

公开(公告)日：2013-04-30

申请号：US13447738

申请日：2012-04-16

申请人： Jungwon Lee ,  Qing Zhao

发明人： Jungwon Lee ,  Qing Zhao

IPC分类号： H04L27/06

CPC分类号： H04L27/2647 ,  H04L5/0007 ,  H04L25/0224 ,  H04L27/2613 ,  H04L27/2656 ,  H04L27/2657 ,  H04L27/2662

摘要： A system including a magnitude measuring module, an energy normalization module, and a metric generation module. The magnitude measuring module is configured to measure magnitudes of real portions of differentially demodulated signals, wherein the differentially demodulated signals are generated by differential demodulation of signals received from a base station. The energy normalization module is configured to generate a sum of energies of a plurality of subcarriers included in the signals received from the base station. The metric generation module is configured to generate a plurality of metrics for a plurality of symbols included in the signals received from the base station. The metric generation module is further configured to detect, based on the plurality of metrics, a preamble symbol included in the signals received from the base station.

摘要翻译： 一种包括幅度测量模块，能量归一化模块和度量生成模块的系统。 幅度测量模块被配置为测量差分解调信号的实部的幅度，其中通过对从基站接收的信号的差分解调产生差分解调信号。 能量归一化模块被配置为生成包括在从基站接收的信号中的多个子载波的能量之和。 度量生成模块被配置为为从基站接收的信号中包括的多个符号生成多个度量。 度量生成模块还被配置为基于多个度量来检测包括在从基站接收的信号中的前导码符号。

公开(公告)号：US08005155B1

公开(公告)日：2011-08-23

申请号：US12002610

申请日：2007-12-18

申请人： Jungwon Lee ,  Qing Zhao

发明人： Jungwon Lee ,  Qing Zhao

IPC分类号： H04K1/10

CPC分类号： H04L27/2647 ,  H04L5/0007 ,  H04L25/0224 ,  H04L27/2613 ,  H04L27/2656 ,  H04L27/2657 ,  H04L27/2662

摘要： A system includes an input, a differential demodulation module, a magnitude measuring module, a summing module, and a metric generator module. The input receives input signals that include s sets of modulated sub-carriers carrying symbols, where s is an integer greater than or equal to 1. The differential demodulation module generates differentially demodulated signals based on the input signals. The magnitude measuring module measures magnitudes of real portions of the differentially demodulated signals. The summing module generates s sums, wherein each of the s sums is a sum of the magnitudes generated based on a respective one of the s sets. The metric generator module generates metrics for the symbols based on the s sums.

摘要翻译： 系统包括输入，差分解调模块，幅度测量模块，求和模块和度量发生器模块。 输入接收输入信号，该输入信号包括携带符号的调制子载波组，其中s是大于或等于1的整数。差分解调模块基于输入信号产生差分解调的信号。 幅度测量模块测量差分解调信号的实部的幅度。 求和模块产生s和，其中s个和中的每一个是基于s集合中的相应一个生成的量值的总和。 度量生成器模块基于s个和值生成符号的度量。

公开(公告)号：US08488698B1

公开(公告)日：2013-07-16

申请号：US13194093

申请日：2011-07-29

申请人： Qing Zhao ,  Jungwon Lee ,  Leilei Song ,  Songping Wu ,  Hui-Ling Lou

发明人： Qing Zhao ,  Jungwon Lee ,  Leilei Song ,  Songping Wu ,  Hui-Ling Lou

IPC分类号： H04K1/10 ,  H04L27/28

CPC分类号： H04L27/2656 ,  H04L27/2676

摘要： In a method for synchronizing a receiver to a synchronous signal, in a signal having been processed based on an automatic gain control (AGC) with a varying gain, a symbol is detected. An estimated beginning of a subsequent frame is determined based on the detected symbol. A gain of the AGC is fixed for a period during which the estimated start of the subsequent frame is processed by the AGC. A transform of the signal is analyzed to determine if the estimated start of the subsequent frame corresponds to an actual start of the subsequent frame. If the estimated start of the subsequent frame does not corresponds to the actual start of the subsequent frame, the gain of the AGC is allowed to resume varying and, a further symbol in the signal is detected, the signal having been processed based on the varying gain of the AGC.

摘要翻译： 在用于将接收机同步到同步信号的方法中，在基于具有变化增益的自动增益控制（AGC）处理的信号中，检测到符号。 基于检测到的符号确定后续帧的估计开始。 AGC的增益在AGC期间处理后续帧的估计开始的期间是固定的。 分析信号的变换以确定后续帧的估计开始是否对应于后续帧的实际开始。 如果后续帧的估计开始不对应于后续帧的实际开始，则允许AGC的增益恢复变化，并且检测到信号中的另外的符号，该信号已经根据变化 增益AGC。

公开(公告)号：US07970066B1

公开(公告)日：2011-06-28

申请号：US11963294

申请日：2007-12-21

申请人： Jungwon Lee ,  Qing Zhao ,  Hui-Ling Lou

发明人： Jungwon Lee ,  Qing Zhao ,  Hui-Ling Lou

IPC分类号： H04L27/28

CPC分类号： H04L27/08 ,  H03G3/3052 ,  H03G3/3078 ,  H04L27/2626

摘要： A system includes an input, a variable gain amplifier (VGA), and an automatic gain control (AGC) module. The input receives an input signal. The input signal includes frames of N symbols modulated using orthogonal frequency division multiplexing (OFDM), wherein a cyclic prefix (CP) precedes each of the N symbols, and wherein N is an integer greater than 1. The VGA provides a gain when amplifying the input signal. The AGC module selectively adjusts the gain of the VGA during the CP preceding M of the N symbols, wherein M is an integer greater than 1.

摘要翻译： 一种系统包括输入，可变增益放大器（VGA）和自动增益控制（AGC）模块。 输入接收输入信号。 输入信号包括使用正交频分复用（OFDM）调制的N个符号的帧，其中循环前缀（CP）在N个符号之前，并且其中N是大于1的整数。当VGA放大 输入信号。 AGC模块在N个符号之前的M之前的CP期间选择性地调整VGA的增益，其中M是大于1的整数。

公开(公告)号：US08804691B1

公开(公告)日：2014-08-12

申请号：US12540758

申请日：2009-08-13

申请人： Qing Zhao ,  Chuxiang Li ,  Leilei Song ,  Jungwon Lee

发明人： Qing Zhao ,  Chuxiang Li ,  Leilei Song ,  Jungwon Lee

IPC分类号： H04L27/26 ,  H04W56/00 ,  H04W88/02

CPC分类号： H04L27/2659 ,  H04L27/2613 ,  H04L27/2672 ,  H04L27/2675 ,  H04L27/2684 ,  H04W56/00 ,  H04W88/02

摘要： Devices, methods, and other embodiments associated with phase based preamble detection are described. In one embodiment, an apparatus includes a wireless transceiver, an evaluation logic, and a configuration logic. The wireless transceiver receives a wireless signal from a wireless device. The wireless signal includes a preamble sequence. The evaluation logic evaluates the preamble sequence by comparing phases of the preamble sequence to phases of predefined preamble sequences to identify a matching preamble sequence. The comparison is done without using amplitude information. The configuration logic configures the wireless transceiver to synchronize wireless communications with the wireless device based, at least in part, on the matching preamble sequence.

摘要翻译： 描述了与基于相位的前导码检测相关联的设备，方法和其他实施例。 在一个实施例中，一种装置包括无线收发器，评估逻辑和配置逻辑。 无线收发器从无线设备接收无线信号。 无线信号包括前序序列。 评估逻辑通过将前导序列的相位与预定义的前导码序列的相位进行比较来评估前导序列，以识别匹配的前导码序列。 比较不使用振幅信息。 配置逻辑配置无线收发器以至少部分地基于匹配的前导码序列来与无线设备同步无线通信。

公开(公告)号：US08279955B1

公开(公告)日：2012-10-02

申请号：US12353391

申请日：2009-01-14

申请人： Qing Zhao ,  Souvik Dihidar ,  Leilei Song ,  Jungwon Lee

发明人： Qing Zhao ,  Souvik Dihidar ,  Leilei Song ,  Jungwon Lee

IPC分类号： H04K1/10

CPC分类号： H04L27/2647 ,  H04L25/06

摘要： In accordance with the teachings described herein, systems and methods are provided for calibrating DC offset in a receiver. A DC calibration circuit may be used that is configured to receive a digital multi-carrier modulated (MCM) signal that includes a sequence of MCM symbols. The DC calibration circuit may include an accumulator and a compensator. The accumulator may be used to determine an estimated DC offset of a current MCM symbol in the sequence of MCM symbols. The compensator may be used to remove the estimated DC offset from a next MCM symbol in the sequence of MCM symbols. The accumulator may also be used to receive a plurality of digital samples that comprise the current MCM symbol and to determine the estimated DC offset by calculating an average of the plurality of digital samples.

摘要翻译： 根据本文所述的教导，提供了用于校准接收机中的DC偏移的系统和方法。 可以使用DC校准电路，其被配置为接收包括MCM符号序列的数字多载波调制（MCM）信号。 DC校准电路可以包括蓄电池和补偿器。 可以使用累加器来确定MCM符号序列中的当前MCM符号的估计DC偏移。 补偿器可以用于从MCM符号序列中的下一个MCM符号中去除估计的DC偏移。 累加器还可以用于接收包括当前MCM符号的多个数字样本，并且通过计算多个数字样本的平均值来确定估计的DC偏移。

公开(公告)号：US08254503B1

公开(公告)日：2012-08-28

申请号：US13169691

申请日：2011-06-27

申请人： Jungwon Lee ,  Qing Zhao ,  Hui-Ling Lou

发明人： Jungwon Lee ,  Qing Zhao ,  Hui-Ling Lou

IPC分类号： H04B14/06 ,  H04L27/28

CPC分类号： H04L27/08 ,  H03G3/3052 ,  H03G3/3078 ,  H04L27/2626

摘要： An automatic gain control tracking system including a variable gain amplifier and an automatic gain control module. The variable gain amplifier is configured to amplify an input signal in accordance with a first gain, in which i) the input signal comprises a plurality of orthogonal frequency domain multiplexing (OFDM) symbols, and ii) each of the plurality of orthogonal frequency domain multiplexing (OFDM) symbols in the input signal is preceded by a respective cyclic prefix. The automatic gain control module configured to vary the first gain of the variable gain amplifier during the respective cyclic prefix preceding each of the plurality of orthogonal frequency domain multiplexing (OFDM) symbols in the input signal.

摘要翻译： 一种包括可变增益放大器和自动增益控制模块的自动增益控制跟踪系统。 可变增益放大器被配置为根据第一增益放大输入信号，其中i）输入信号包括多个正交频域复用（OFDM）符号，以及ii）多个正交频域复用中的每一个 （OFDM）符号之前是相应的循环前缀。 所述自动增益控制模块被配置为在所述输入信号中的所述多个正交频域复用（OFDM）符号中的每一个之前的相应循环前缀期间改变所述可变增益放大器的第一增益。

公开(公告)号：US08964789B1

公开(公告)日：2015-02-24

申请号：US12609862

申请日：2009-10-30

申请人： Jungwon Lee ,  Jiwoong Choi ,  Qing Zhao ,  Hui-Ling Lou

发明人： Jungwon Lee ,  Jiwoong Choi ,  Qing Zhao ,  Hui-Ling Lou

IPC分类号： H04J3/06

CPC分类号： H04L27/2643 ,  H04L7/042 ,  H04L27/2613 ,  H04L27/2656 ,  H04L2027/0026

摘要： Methods and apparatus for data synchronization in communication systems using repetitive preamble patterns. In one embodiment, a method includes receiving a signal, where the received signal includes a data unit. The data unit includes a preamble symbol, and the preamble symbol has a start time and includes Q portions, each having the same pattern. The method further includes determining multiple possible values of a frame timing (FT). The method further includes determining multiple correlation functions including at least one correlation function corresponding to each of the multiple possible values of the FT, such that a given correlation function corresponding to a given possible value of the FT represents a correlation between data in two non-adjacent portions of the Q portions associated with the given FT. The method further includes selecting one of the multiple possible values of the FT based at least in part on the multiple determined correlation functions.

摘要翻译： 使用重复前导码模式的通信系统中的数据同步的方法和装置。 在一个实施例中，一种方法包括接收信号，其中所接收的信号包括数据单元。 数据单元包括前导符号，并且前导码符号具有开始时间，并且包括各自具有相同模式的Q个部分。 该方法还包括确定帧定时（FT）的多个可能值。 该方法还包括确定包括与FT的多个可能值中的每一个相对应的至少一个相关函数的多个相关函数，使得对应于FT的给定可能值的给定相关函数表示两个非可变值中的数据之间的相关性， 与给定FT相关联的Q部分的相邻部分。 该方法还包括至少部分地基于多个确定的相关函数来选择FT的多个可能值中的一个。