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1. 发明授权

US06370397B1 Search window delay tracking in code division multiple access communication systems 失效
标题翻译：在码分多址通信系统中搜索窗口延迟跟踪
公开(公告)号：US06370397B1
公开(公告)日：2002-04-09
申请号：US09070778
申请日：1998-05-01
申请人： Branislav M. Popović , Frank Georg , Matthlas Schulist , Göran Klang
发明人： Branislav M. Popović , Frank Georg , Matthlas Schulist , Göran Klang
IPC分类号： H04B138
CPC分类号： H04B1/7085 , G01S5/0215 , H04B1/7113 , H04B1/7117
摘要： The present invention provides a search window delay tracking procedure for use in a multipath search processor of a CDMA radio receiver. A channel impulse responses is estimated for a received signal containing plural paths, each path having a corresponding path delay. A search window defines a delay profile that contains the plural paths of the received signal. A mean or average delay is calculated for the estimated channel impulse response (CIR), and an error is determined between the mean CIR delay and a desired delay position corresponding to the center of the CIR search window. An adjustment is made to reduce that error so that the center of the search window and the mean CIR delay are aligned. The error may be processed either linearly (in one embodiment) or non-linearly (in another embodiment) to minimize the error and to reduce an influence of noise. A non-linear filtering process includes calculating a delay spread from the mean CIR delay calculated for successive processing cycles of a window delay tracking procedure corresponding to each new input. A difference is determined between the successive delay spreads. Adjustment signal is set equal to the error signal if the difference is less than or equal to a threshold. Alternatively, the adjustment signal is set to zero if the difference is greater than the threshold. Consequently, if the delay spread in the current iteration is significantly different from the delay spread in the previous iteration, the new error sample calculated in the current iteration is considered unreliable, and no adjustment is made.
摘要翻译：本发明提供了一种在CDMA无线电接收机的多路径搜索处理器中使用的搜索窗延迟跟踪程序。对于包含多个路径的接收信号估计信道脉冲响应，每个路径具有对应的路径延迟。搜索窗口定义包含接收信号的多个路径的延迟分布。对于估计的信道脉冲响应（CIR）计算平均或平均延迟，并且在平均CIR延迟和对应于CIR搜索窗口的中心的期望延迟位置之间确定误差。进行调整以减少该误差，使得搜索窗口的中心和平均CIR延迟对齐。该错误可以线性地（在一个实施例中）或非线性（在另一个实施例中）处理以最小化误差并减少噪声的影响。非线性滤波处理包括从对应于每个新输入的窗延迟跟踪程序的连续处理周期计算的平均CIR延迟来计算延迟扩展。在连续的延迟传播之间确定差异。如果差值小于或等于阈值，则将调整信号设置为等于误差信号。或者，如果差值大于阈值，则将调整信号设置为零。因此，如果当前迭代中的延迟扩展与前一次迭代中的延迟扩展明显不同，则在当前迭代中计算出的新的误差样本被认为是不可靠的，不进行调整。

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