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    • 8. 发明授权
    • Method for OFDM signal identification and parameter estimation
    • OFDM信号识别和参数估计方法
    • US08160163B1
    • 2012-04-17
    • US12187035
    • 2008-08-06
    • Tevfik YucekHuseyin Arslan
    • Tevfik YucekHuseyin Arslan
    • H04K1/10
    • H04W16/14H04L27/0006
    • Spectrum sensing is one of the most challenging problems in cognitive radio systems. The spectrum of interest needs to be characterized and unused frequencies should be identified for possible exploitation in a simple and fast way, allowing the radio to catch up with the changing transmission parameters. A sensing method is presented where primary users are identified by matching the features extracted from the received signal to the a priori information about primary users' transmission characteristics. For estimation of some signal parameters, the cyclostationarity of the transmission spectrum is explored by using a suboptimal maximum likelihood (ML) estimator. The proposed algorithms can be used in cognitive radio for identifying various transmissions and for electronic surveillance.
    • 频谱感知是认知无线电系统中最具挑战性的问题之一。 需要对频谱进行表征,并以简单快速的方式识别未使用的频率以便可能的开发,从而使无线电能够赶上变化的传输参数。 提出了一种感测方法,其中主要用户通过将从接收到的信号提取的特征与关于主要用户的传输特性的先验信息进行匹配来识别。 为了估计一些信号参数,通过使用次优最大似然(ML)估计器来探索传输频谱的周期平稳性。 所提出的算法可用于认知无线电中,用于识别各种传输和电子监视。
    • 10. 发明授权
    • Noise plus interference power estimation method for OFDM systems
    • OFDM系统的噪声加干扰功率估计方法
    • US07688905B1
    • 2010-03-30
    • US11428473
    • 2006-07-03
    • Tevfik YucekHuseyin Arslan
    • Tevfik YucekHuseyin Arslan
    • H04K1/10
    • H04B1/1027H04B17/345H04L27/2647
    • In accordance with the present invention, a method and apparatus for estimating the noise and interference over the transmission band for OFDM systems are provided. Noise variance and signal-to-noise ratio (SNR) are important parameters for adaptive orthogonal frequency division multiplexing (OFDM) systems since they serve as a standard measure of signal quality. Conventional algorithms assume that the noise statistics remain constant over the OFDM frequency band, and thereby average the instantaneous noise samples to get a single estimate. In reality, noise is often made up of white Gaussian noise along with correlated colored noise that affects the OFDM spectrum unevenly. Provided is an adaptive windowing technique to estimate the noise power that takes into account the variation of the noise statistics across the OFDM sub-carrier index as well as across OFDM symbols. The proposed method provides many local estimates, allowing tracking of the variation of the noise statistics in frequency and time. A mean-squared-error (MSE) expression in order to choose the optimal window dimensions for averaging in time and frequency is derived.
    • 根据本发明,提供了一种用于估计OFDM系统的传输频带上的噪声和干扰的方法和装置。 噪声方差和信噪比(SNR)是自适应正交频分复用(OFDM)系统的重要参数,因为它们用作信号质量的标准测量。 传统算法假定噪声统计在OFDM频带上保持恒定,从而平均瞬时噪声样本以获得单个估计。 实际上,噪声通常由白高斯噪声以及影响OFDM频谱不均匀的相关色噪声组成。 提供了一种自适应加窗技术来估计考虑到OFDM子载波索引以及跨越OFDM符号的噪声统计的变化的噪声功率。 所提出的方法提供了许多局部估计,允许跟踪噪声统计在频率和时间上的变化。 导出了平均误差(MSE)表达式,以便选择用于在时间和频率上求平均的最优窗口维数。