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    • 3. 发明申请
    • OFDM communications apparatus, OFDM communications method, and OFDM communications program
    • OFDM通信装置,OFDM通信方法和OFDM通信程序
    • US20030128660A1
    • 2003-07-10
    • US10331904
    • 2002-12-31
    • Atsushi ItoTomohiro KimuraMasahiro Ishii
    • G01R031/08
    • H04L27/2657H04L27/2675H04L2027/0028H04L2027/0055H04L2027/0075H04L2027/0091
    • An object of the present invention is provide an OFDM communications apparatus for achieving a phase correcting a highly-accurate phase correcting process which does not gradually lose accuracyor requiring large hardware. An Arctan vector phase rotator 104 calculates a phase of a vector signal. A phase correction information estimator 105 finds an estimated multipath-fading deviation value from the phase of a vector in a phase error estimation symbol 207, and also finds an estimated non-multipath-fading deviation value from the phase of a vector in a pilot signal 209. An adder 106 adds these two estimated deviation values together for output as a total phase correction value. Based on the total phase correction value, the Arctan vector phase rotator 104 rotates the phase of a vector to be demodulated for phase correction.
    • 本发明的目的是提供一种OFDM通信装置,用于实现相位校正高精度相位校正处理,该处理不会逐渐失去要求较大硬件的精度。 Arctan矢量相位旋转器104计算矢量信号的相位。 相位校正信息估计器105从相位误差估计符号207中的向量的相位中求出估计的多径衰落偏差值,并且还从导频信号中的向量的相位求出估计的非多径衰落偏差值 加法器106将这两个估计偏差值相加在一起作为总相位校正值输出。 基于总相位校正值,Arctan矢量相位旋转器104使要解调的矢量的相位旋转以进行相位校正。
    • 8. 发明授权
    • Robust OFDM carrier recovery methods and apparatus
    • 稳健的OFDM载波恢复方法和装置
    • US07139340B2
    • 2006-11-21
    • US10185971
    • 2002-06-28
    • Carl G. Scarpa
    • Carl G. Scarpa
    • H04L27/06
    • H04L27/266H04L27/2659H04L27/2675H04L27/2679H04L2027/0028H04L2027/0075H04L2027/0095
    • Methods and apparatus for estimating and correcting carrier frequency offsets in a bust multi-tone receiver are described. Course and fine carrier frequency estimates are generated from the signal's preamble. Decision directed carrier frequency offset estimates are then generated from the signal field and data fields of the multi-tone signal. Frequency error estimates are generated for each tone of the signal and combined using a weighted average to generate the frequency error estimate used to perform the correction operation. Error estimates corresponding to noisy data tones are weighted less then estimates corresponding to less noisy data tones. In cases of low SNR frequency error estimates corresponding to pilots are weighted by an extra amount as compared to error estimates corresponding to tones used to transmit data symbols. During times of high SNR error estimates corresponding to pilot tones are weighted in the same manner as error estimates corresponding to data tones.
    • 描述了用于估计和校正胸围多音调接收机中的载波频率偏移的方法和装置。 从信号的前导码生成课程和精细载波频率估计。 然后根据多音调信号的信号场和数据场产生决策导向载波频率偏移估计。 针对信号的每个音调产生频率误差估计,并使用加权平均值组合以产生用于执行校正操作的频率误差估计。 与噪声数据音调相对应的误差估计被加权小于对应于较少嘈杂数据音调的估计。 在低SNR的情况下,与对应于用于发送数据符号的音调的误差估计值相比,对应于导频的估计值加权额外的量。 在高SNR的时间期间,对应于导频音调的误差估计以与对应于数据音调的误差估计相同的方式进行加权。
    • 9. 发明授权
    • System and method for automatic frequency control in spread spectrum communications
    • 扩频通信中自动频率控制的系统和方法
    • US06728301B1
    • 2004-04-27
    • US09612536
    • 2000-07-07
    • George Chrisikos
    • George Chrisikos
    • H04B169
    • H04B1/7087H04B1/7115H04B2201/70701H04L2027/0055H04L2027/0075
    • A method is providing for calculating local oscillator phase errors in a code division multiple access (CDMA) receiver using an arctangent calculation of the difference vectors between sample stream (multipath) delays. Instead of the conventional cross-product calculation of pilot symbols, a phase correction, using both real and imaginary parts of the complex conjugate, is preformed in each sample stream delay path before the step of maximal-ratio combining (MRC). The weighted combination is then selectively filtered and accumulated, depending on whether the automatic frequency control (AFC) loop is tracking or acquiring. Then, an arctangent polynomial approximation is used to find the actual phase error. An AFC system using the above-mentioned MRC combination and arctangent calculation of phase error is also provided.
    • 一种方法是使用采样流(多径)延迟之间的差矢量的反正切计算来计算码分多址(CDMA)接收机中的本地振荡器相位误差。 代替导频符号的常规交叉乘积计算,在最大比组合(MRC)的步长之前,在每个采样流延迟路径中执行使用复共轭的实部和虚部的相位校正。 然后根据自动频率控制(AFC)循环是跟踪还是获取,选择性地过滤和累加加权组合。 然后,使用反正切多项式近似来找到实际的相位误差。 还提供了使用上述MRC组合的AFC系统和相位误差的反正切计算。