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    • 93. 发明授权
    • Automatic gain control apparatus and method in an orthogonal frequency division multiple access system
    • 一种正交频分多址系统中的自动增益控制装置及方法
    • US07822153B2
    • 2010-10-26
    • US11348345
    • 2006-02-07
    • Yong-Chul SongYoung-Mo GuMin-Goo Kim
    • Yong-Chul SongYoung-Mo GuMin-Goo Kim
    • H04L27/06
    • H03G3/3063
    • An automatic gain control (AGC) apparatus of a wireless mobile terminal, and method, in an orthogonal frequency division multiple access (OFDMA) system. A gain amplifier controls an amplification gain of received analog symbols. An analog-to-digital converter converts the received analog symbols into a digital signal. A fast Fourier transform (FFT) unit converts the digital signal into a frequency-domain signal. A power measurer measures power in the frequency domain in units of sub-carriers. A sub-carrier power accumulator detects a sub-carrier carrying a signal, and accumulates its power value. A sub-carrier average power measurer estimates an average power value transmitted per sub-carrier from the accumulated power value. A control means compares the estimated average power value with a reference power value, and generates a control signal used for controlling a gain of the gain amplifier according to the comparison result.
    • 一种在正交频分多址(OFDMA)系统中的无线移动终端的自动增益控制(AGC)装置和方法。 增益放大器控制接收的模拟符号的放大增益。 模数转换器将接收的模拟符号转换为数字信号。 快速傅里叶变换(FFT)单元将数字信号转换成频域信号。 功率测量器以子载波为单位测量频域的功率。 子载波功率累加器检测携带信号的子载波,并累加其功率值。 子载波平均功率测量器估计从累积功率值发送的每个副载波的平均功率值。 控制装置将估计的平均功率值与参考功率值进行比较,并且根据比较结果产生用于控制增益放大器的增益的控制信号。
    • 94. 发明授权
    • Apparatus and method for recovering frequency in an orthogonal frequency division multiplexing system
    • 在正交频分复用系统中恢复频率的装置和方法
    • US07733971B2
    • 2010-06-08
    • US11606353
    • 2006-11-30
    • Hee-Jin RohSu-Jin YoonMin-Goo Kim
    • Hee-Jin RohSu-Jin YoonMin-Goo Kim
    • H04K1/10
    • H04L27/266H04L27/2659H04L27/2675H04L27/2686
    • An apparatus and method for recovering a carrier frequency of a received signal using a predefined symbol in an OFDM system is provided. A maximum value detector detects at least three values and their corresponding offsets in descending order among auto-correlation values calculated within a specific frequency offset range between a received signal and a predefined symbol. A frequency offset corrector compares a ratio of a first auto-correlation value to a second auto-correlation value with a predetermined first threshold, determines whether first and second frequency offsets corresponding to the first and second auto-correlation values are adjacent to each other if the ratio of the auto-correlation values is less than the first threshold, and determines an initial carrier frequency offset using a difference between the first frequency offset and a frequency offset correction value determined according to system, if the first and second frequency offsets are adjacent to each other and a ratio of the second auto-correlation value and a third auto-correlation value is greater than a predetermined second threshold.
    • 提供了一种用于在OFDM系统中使用预定符号来恢复接收信号的载波频率的装置和方法。 最大值检测器在接收信号和预定义符号之间的特定频率偏移范围内计算的自相关值之中以降序检测至少三个值及其相应的偏移。 频率偏移校正器将第一自相关值与第二自相关值的比率与预定的第一阈值进行比较,确定与第一和第二自相关值对应的第一和第二频率偏移是否彼此相邻如果 所述自相关值的比率小于所述第一阈值,并且如果所述第一和第二频率偏移相邻,则使用根据系统确定的所述第一频率偏移和频率偏移校正值之间的差来确定初始载波频率偏移 并且第二自相关值和第三自相关值的比率大于预定的第二阈值。
    • 99. 发明申请
    • Apparatus and method for carrier frequency synchronization in an OFDM system
    • OFDM系统中载波频率同步的装置和方法
    • US20070133391A1
    • 2007-06-14
    • US11605484
    • 2006-11-29
    • Hee-Jin RohSu-Jin YoonMin-Goo Kim
    • Hee-Jin RohSu-Jin YoonMin-Goo Kim
    • H04J11/00H04J1/00
    • H04L27/2675H04L27/2659H04L27/2672H04L27/2684H04L27/2688
    • An apparatus and method for carrier frequency synchronization in an Orthogonal Frequency Division Multiplexing (OFDM) system are provided for correcting an initial carrier frequency offset in the OFDM system. A metric generator for frequency estimation performs a first accumulation process for a value computed by multiplying a Phase Reference Symbol (PRS) generated from a reception stage by a Fast Fourier Transform (FFT) output signal for an OFDM symbol in a PRS position within a frame, acquires a differential symbol from a product of adjacent FFT output symbols, performs a second accumulation process for a real part extracted from the differential symbol, and outputs a metric value for the frequency estimation. A maximal value-related index generator compares metric values for initial frequency estimation within a predetermined frequency offset estimation range, and selects and outputs a maximal metric value as a frequency offset estimate.
    • 提供了一种用于正交频分复用(OFDM)系统中的载波频率同步的装置和方法,用于校正OFDM系统中的初始载波频率偏移。 用于频率估计的度量发生器对通过将从接收级产生的相位参考符号(PRS)乘以帧内的PRS位置中的OFDM符号的快速傅立叶变换(FFT)输出信号而计算的值进行第一累积处理 从相邻FFT输出符号的乘积获取差分符号,对从差分符号提取的实部执行第二累积处理,并输出用于频率估计的度量值。 最大值相关索引发生器将预定频率偏移估计范围内的初始频率估计的度量值进行比较,并且选择并输出最大度量值作为频率偏移估计。