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公开(公告)号：US06269131B1
公开(公告)日：2001-07-31
申请号：US09086974
申请日：1998-05-28
IPC分类号： H04B1500
CPC分类号： H04L25/023 , H04L25/025
摘要： A physical channel estimator for a communication system using pilot symbols and an equalizer uses a model of the system in which the impulse response of the physical channel is considered separately from the impulse responses of the pulse shaping filters in the transmitter and receiver of the communication system. The system is modeled as if the signals were propagated first through both pulse shaping filters and then through the physical channel. To estimate the physical channel impulse response, known pilot symbols are transmitted and then sampled. The pilot symbol samples and the known impulse responses of the pulse shaping filters are then used to estimate the physical channel impulse response. In one embodiment, the physical channel impulse response is considered time-invariant over the estimation period and a sufficient number of pilot symbol samples are taken so that the system is overdetermined. A least squares method is then used to estimate the physical channel impulse response from the pilot symbol samples and the known responses of the pulse shaping filters. Further refinements include conditioning the estimated physical channel impulse response to improve performance in low SNR conditions and estimating a DC offset incurred from demodulating the received signal.
摘要翻译： 用于使用导频符号和均衡器的通信系统的物理信道估计器使用系统的模型，其中物理信道的脉冲响应与通信系统的发射机和接收机中的脉冲整形滤波器的脉冲响应分开考虑 。 该系统被建模为首先通过两个脉冲整形滤波器然后通过物理信道传播信号。 为了估计物理信道脉冲响应，发送已知的导频符号然后采样。 然后使用导频符号采样和脉冲整形滤波器的已知脉冲响应来估计物理信道脉冲响应。 在一个实施例中，物理信道脉冲响应在估计周期内被认为是时间不变的，并且采用足够数量的导频符号样本，使得系统被过度确定。 然后使用最小二乘法来估计来自导频符号样本的物理信道脉冲响应和脉冲整形滤波器的已知响应。 进一步的改进包括调整估计的物理信道脉冲响应以改善低SNR条件下的性能并且估计从解调接收到的信号引起的DC偏移。
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公开(公告)号：US6049577A
公开(公告)日：2000-04-11
申请号：US86794
申请日：1998-05-28
摘要： A pattern detector adapted for wireless communication systems includes an error calculator, a comb filter, an averager, and a threshold detector. The pattern to be detected is a sequence of pilot signal patterns whose error calculation is relatively invariant with respect to frequency offset introduced by Doppler and the local oscillator. The pattern detector processes received input samples y.sub.k to determine an error signal from the input samples y.sub.k and estimated input samples y.sub.k. The estimated input samples y.sub.k are determined using an estimated channel impulse response. When a vector of the received input samples is "aligned" with the expected header sync input samples, the level of the error signal is about equal to the level of the noise. The pattern detector determines the average level of the error signals for the last K error signals of each sample position E.sub.Kn within a pilot pattern, where K corresponds to the number of pilot patterns in a header sync pattern and n corresponds to the sample position. The pattern detector also determines the average level of the error signals E.sub.L corresponding to the last L received input samples, where L corresponds to the number of samples in a header sync sequence. When E.sub.Kn for a sample position is lower than a preselected threshold percentage of E.sub.L, the header sync pattern is deemed detected. Finally, the end of the header sync pattern is determined by the location of the minimum E.sub.Kn. This minimum is found by calculating, once the header is deemed detected, values for E.sub.Kn that are a certain number of samples past the last minimum.
摘要翻译： 适用于无线通信系统的模式检测器包括误差计算器，梳状滤波器，平均器和阈值检测器。 要检测的模式是导频信号模式的序列，其误差计算相对于由多普勒和本地振荡器引入的频率偏移是相对不变的。 模式检测器处理接收到的输入样本+ E，ovs y + EE k，以从输入样本+ E，ovs y + EE k和估计输入样本+ E，cir y + EE k确定误差信号。 使用估计的信道脉冲响应确定估计输入样本+ E，cir y + EE k。 当所接收的输入采样的矢量与期望的报头同步输入采样“对准”时，误差信号的电平约等于噪声的电平。 模式检测器确定导频模式中每个采样位置EKn的最后K个误差信号的误差信号的平均电平，其中K对应于报头同步模式中的导频模式的数量，n对应于采样位置。 模式检测器还确定对应于最后L个接收输入采样的误差信号EL的平均电平，其中L对应于报头同步序列中的采样数。 当采样位置的EKn低于EL的预选阈值百分比时，认为检测到标题同步模式。 最后，头部同步模式的结束由最小EKn的位置决定。 通过计算找到该最小值，一旦检测到标题，则EKn的值超过了最后一个最小值的一定数量的样本。
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公开(公告)号：US06097933A
公开(公告)日：2000-08-01
申请号：US185286
申请日：1998-11-03
申请人： Steven J. Bennett , Marlo Rene Gothe , Kenneth Lee
发明人： Steven J. Bennett , Marlo Rene Gothe , Kenneth Lee
CPC分类号： H04B1/1615 , H04W52/0216 , H04W52/0283 , H04W52/0229 , H04W88/022 , Y02B60/50
摘要： A paging protocol includes header synchronization and system information segments containing information that allows a pager to conserve power. These segments can indicate a schedule of transmissions, and the channels of other transmissions. The pager can use this information to reduce the time the pager is in a high-power mode. In addition, the addresses are ordered so that the pager can more quickly determine whether a page is addressed to that particular pager. Further, the pager can activate circuitry in a sequenced manner to reduce peak power usage. The transmissions on different channels are synchronized in an offset manner so that the pager can scan one channel and switch to a next channel and immediately receive the start of a frame. Still further, the pager can be configured to perform narrowing searches during the initial acquisition process, which are then widened if no active channels are detected. If, after the widened search, still no active channels are detected, it is assumed that the pager is no longer in the service area. The pager enters an extended low-power mode to conserve power until the pager is moved back into the service area. The paging system and the pager also monitor the time between pages addressed to that pager and decrease the frequency of searches when the pager receives few pages. The paging system appropriately schedules a page when, eventually, a caller sends a page to that pager.
摘要翻译： 寻呼协议包括报头同步和包含允许寻呼机节省功率的信息的系统信息段。 这些段可以指示传输的时间表和其他传输的信道。 寻呼机可以使用此信息来减少寻呼机处于高功率模式的时间。 此外，地址被排序，使得寻呼机可以更快地确定页面是否寻址到该特定寻呼机。 此外，寻呼机可以以有序的方式激活电路以减少峰值功率使用。 不同信道上的传输以偏移方式同步，使得寻呼机可以扫描一个信道并切换到下一个信道，并立即接收帧的开始。 此外，寻呼机可以被配置为在初始捕获处理期间执行缩小搜索，然后如果没有检测到活动信道，则扩展它们。 如果在扩大的搜索之后，仍然没有检测到活动信道，则假设寻呼机不再在服务区域中。 寻呼机进入扩展的低功耗模式以节省电力，直到寻呼机移回服务区域。 寻呼系统和寻呼机还监视寻呼机寻址的页面之间的时间，并在寻呼机接收到几页时降低搜索频率。 当呼叫者最终发送一个页面到该寻呼机时，寻呼系统适当地安排一个页面。
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公开(公告)号：US6112055A
公开(公告)日：2000-08-29
申请号：US267408
申请日：1999-03-10
申请人： Steven J. Bennett , Marlo Rene Gothe , Kenneth Lee
发明人： Steven J. Bennett , Marlo Rene Gothe , Kenneth Lee
CPC分类号： H04B1/1615 , H04W52/0216 , H04W52/0283 , H04W52/0229 , H04W88/022 , Y02B60/50
摘要： A paging protocol includes header synchronization and system information segments containing information that allows a pager to conserve power. These segments can indicate a schedule of transmissions, and the channels of other transmissions. The pager can use this information to reduce the time the pager is in a high-power mode. In addition, the addresses are ordered so that the pager can more quickly determine whether a page is addressed to that particular pager. Further, the pager can activate circuitry in a sequenced manner to reduce peak power usage. The transmissions on different channels are synchronized in an offset manner so that the pager can scan one channel and switch to a next channel and immediately receive the start of a frame. Still further, the pager can be configured to perform narrowing searches during the initial acquisition process, which are then widened if no active channels are detected. If, after the widened search, still no active channels are detected, it is assumed that the pager is no longer in the service area. The pager enters an extended low-power mode to conserve power until the pager is moved back into the service area. The paging system and the pager also monitor the time between pages addressed to that pager and decrease the frequency of searches when the pager receives few pages. The paging system appropriately schedules a page when, eventually, a caller sends a page to that pager.
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