公开(公告)号：US06771692B2

公开(公告)日：2004-08-03

申请号：US09964589

申请日：2001-09-25

申请人： Roland Reinhard Rick ,  Parvathanathan Subrahmanya ,  Brian K. Butler ,  Shimman Patel ,  Thunyachate Ekvetchavit

发明人： Roland Reinhard Rick ,  Parvathanathan Subrahmanya ,  Brian K. Butler ,  Shimman Patel ,  Thunyachate Ekvetchavit

IPC分类号： H04B1707

CPC分类号： H04B1/7085 ,  H04B1/7115 ,  H04B7/0667 ,  H04B7/0697 ,  H04B2201/70701

摘要： In an antenna diversity environment, the timing offset of the receiver's fingers are based on the timing offset of the received peaks of the base station transmit signals. In a system with non-negligible multipath spacing, the timing offset of the received peaks of the base station transmit signals are not necessarily at the same location. In one embodiment, the demodulating elements for the signal from each base station antenna use the same offset for demodulating and determining an error signal based on pilot signal sampling prior to the timing offset and subsequent to the timing offset. The error signals are averaged and used by a time tracking loop to track the incoming signal. In another embodiment, the demodulating elements for the signal from each base station antenna independently time track the signals with different timing offsets for each finger. The preferred embodiment depends on the method used by the base station to multiplex the data onto multiple transmit antennas.

公开(公告)号：US06480528B1

公开(公告)日：2002-11-12

申请号：US09330440

申请日：1999-06-11

申请人： Shimman Patel ,  Thomas Wilborn

发明人： Shimman Patel ,  Thomas Wilborn

IPC分类号： H04B1707

CPC分类号： H04J1/05 ,  H03G3/3052 ,  H04L5/06

摘要： A method and a receiver for processing a desired signal for decoding (i.e., by a decoder). In accordance with the method, an input signal that includes the desired signal and additional signals is received and filtered with a first filter having a bandwidth greater than a bandwidth of the desired signal. The filtered signal is then sampled to generate discrete time samples, which is then filtered with a discrete time matched filter. The filtered samples are then scaled with a scaling factor and quantized. A quantity related to an amplitude of the quantized samples (i.e., power) is measured, and the scaling factor is adjusted in accordance with the measured quantity. The quantized samples can be further processed (i.e., demodulated) and provided to a decoder. The desired signal can be a quadrature modulated signal, in which case matched filtering, scaling, and quantization are performed on the in-phase and quadrature components of the desired signal. The adjustment of the scaling factor can be performed by an automatic gain control (AGC) loop that compares the measured quantity (e.g., signal power of the quantized samples) against a predetermined value to generate error values. The AGC loop then filters the error values to generate the scaling factor. In an embodiment, the loop filtering can be performed with an integrator.

摘要翻译： 一种用于处理用于解码的期望信号（即，由解码器）的方法和接收器。 根据该方法，包含期望信号和附加信号的输入信号被接收并用具有大于期望信号带宽的带宽的第一滤波器进行滤波。 然后对经滤波的信号进行采样以产生离散时间样本，然后用离散时间匹配滤波器过滤。 然后将经过滤的样品用比例因子缩放并量化。 测量与量化样品的振幅相关的量（即功率），并且根据测量的量调节比例因子。 量化样本可以进一步处理（即解调）并提供给解码器。 期望的信号可以是正交调制信号，在这种情况下，对期望信号的同相和正交分量执行匹配滤波，缩放和量化。 缩放因子的调整可以通过将测量量（例如，量化样本的信号功率）与预定值进行比较以产生误差值的自动增益控制（AGC）循环来执行。 然后，AGC环路对误差值进行滤波以生成比例因子。 在一个实施例中，环路滤波可以用积分器来执行。

公开(公告)号：US07437172B2

公开(公告)日：2008-10-14

申请号：US10316760

申请日：2002-12-10

申请人： Qingxin Chen ,  Shimman Patel

发明人： Qingxin Chen ,  Shimman Patel

IPC分类号： H04B7/00

CPC分类号： H04L1/0061 ,  H04L1/0072 ,  H04L1/20 ,  H04L1/201

摘要： Techniques to detect for DTX frames in a “primary” transmission that may be sent in a non-continuous manner using a “secondary” transmission that is sent during periods of no transmission for the primary transmission. The primary and secondary transmissions may be the ones sent on the F-DCCH and Forward Power Control Subchannel, respectively, in an IS-2000 system. In one method, a determination is first made whether or not a frame received for the primary transmission in a particular frame interval is a good frame (e.g., based on CRC). If the received frame is not a good frame, then a determination is next made whether the received frame is a DTX frame or an erased frame based on a number of metrics determined for the primary and secondary transmissions. The metrics may include symbol error rate of the received frame, secondary transmission (e.g., PC bit) energy, and received frame energy.

摘要翻译： 在“主”传输中检测可以以非连续方式发送的DTX帧的技术，使用在主传输的无传输期间发送的“次”传输。 主要和次要传输可以分别是在IS-2000系统中在F-DCCH和前向功率控制子信道上发送的。 在一种方法中，首先确定在特定帧间隔中为主传输接收的帧是否是良好帧（例如，基于CRC）。 如果接收到的帧不是良好的帧，则接着确定接收到的帧是否是基于针对主传输和次传输确定的度量的数目的DTX帧或已擦除的帧。 度量可以包括接收到的帧的符号错误率，二次传输（例如，PC位）能量和接收到的帧能量。

公开(公告)号：US20080143580A1

公开(公告)日：2008-06-19

申请号：US11739971

申请日：2007-04-25

申请人： Serguei A. Glazko ,  James Edward Beckman ,  Shimman Patel

发明人： Serguei A. Glazko ,  James Edward Beckman ,  Shimman Patel

IPC分类号： H04K3/00 ,  H04B1/10

CPC分类号： H04L27/2647 ,  H04B1/1036 ,  H04K3/228

摘要： Techniques for detecting and suppressing jammers are described. A receiver may perform post-FFT jammer detection and pre-FFT jammer suppression. The receiver may transform an input signal to obtain a frequency-domain signal and may detect for jammers in the input signal based on the frequency-domain signal. The receiver may determine powers of a plurality of carriers based on the frequency-domain signal and may detect for jammers based on peaks in the powers of these carriers. The receiver may filter the input signal (e.g., with a notch filter) to suppress the detected jammers. Alternatively or additionally, the receiver may perform post-FFT jammer detection and post-FFT jammer suppression. The receiver may determine whether jammer is present on each carrier based on data power and channel power for that carrier. The receiver may modify (e.g., zero out or reduce) the frequency-domain signal on carriers with detected jammers.

摘要翻译： 描述了用于检测和抑制干扰的技术。 接收机可以执行FFT后干扰检测和预FFT干扰抑制。 接收机可以变换输入信号以获得频域信号，并且可以基于频域信号来检测输入信号中的干扰。 接收机可以基于频域信号来确定多个载波的功率，并且可以基于这些载波的功率的峰值来检测干扰。 接收机可以过滤输入信号（例如，使用陷波滤波器）来抑制所检测到的干扰。 或者或另外，接收机可以执行FFT后干扰检测和FFT后干扰抑制。 接收机可以基于该载波的数据功率和信道功率来确定每个载波上是否存在干扰信号。 接收机可以利用检测到的干扰来修改（例如，零或降低）载波上的频域信号。

公开(公告)号：US20070086329A1

公开(公告)日：2007-04-19

申请号：US11392266

申请日：2006-03-28

申请人： Serguei Glazko ,  Jonathan Reeves ,  Shimman Patel

发明人： Serguei Glazko ,  Jonathan Reeves ,  Shimman Patel

IPC分类号： H04J11/00

CPC分类号： H04L27/2666 ,  H04L27/2607 ,  H04L27/2662 ,  H04L27/2665 ,  H04N21/2383 ,  H04N21/4382

摘要： Techniques for detecting mode and guard length and estimating timing offset for an OFDM transmission are described. Multiple hypotheses for different combinations of mode and guard length that might have been used for the OFDM transmission are evaluated. For each hypothesis, correlation is performed on received samples for a hypothesized guard interval to obtain correlation results. The energy of the hypothesized guard interval is determined. A first metric is derived based on the correlation results and the energy. The first metric may be filtered, e.g., averaged. Noise is estimated, e.g., based on a set of elements for the filtered first metric at locations determined by an estimated timing offset for the hypothesis. A second metric is derived based on the filtered first metric and the estimated noise. The second metric for all hypotheses may be used to determine the mode, guard length, and timing offset for the OFDM transmission.

摘要翻译： 描述用于检测模式和保护长度并估计OFDM传输的定时偏移的技术。 评估可能已经用于OFDM传输的模式和保护长度的不同组合的多个假设。 对于每个假设，对于假设的保护间隔的接收样本执行相关性以获得相关结果。 确定假设保护间隔的能量。 基于相关结果和能量导出第一个度量。 可以过滤第一度量，例如平均。 估计噪声，例如，基于由用于假设的估计定时偏移确定的位置处的经滤波的第一度量的一组元素。 基于滤波的第一度量和估计的噪声导出第二度量。 所有假设的第二个度量可用于确定OFDM传输的模式，保护长度和定时偏移。

公开(公告)号：US08009745B2

公开(公告)日：2011-08-30

申请号：US11386865

申请日：2006-03-22

申请人： Serguei A. Glazko ,  Kuei-Chiang Lai ,  Shimman Patel

发明人： Serguei A. Glazko ,  Kuei-Chiang Lai ,  Shimman Patel

IPC分类号： H04K1/10

CPC分类号： H04L27/2665 ,  H04L27/2678 ,  H04L27/2688 ,  H04L27/2695

摘要： Techniques for performing time tracking at a receiver are described. A first arriving path (FAP) and a last arriving path (LAP) are detected based on a channel impulse response estimate for a communication channel. The detected FAP and LAP may be correct or swapped. To resolve ambiguity in the detected FAP and LAP, a first hypothesis corresponding to the FAP and LAP being correctly detected and a second hypothesis corresponding to the FAP and LAP being incorrectly detected are evaluated. For each hypothesis, hypothesized FAP and LAP are determined based on the detected FAP and LAP, a correlation window is determined based on the hypothesized FAP and LAP, and correlation is performed using the correlation window. The correct hypothesis is determined based on correlation results for the two hypotheses. The receiver timing is updated based on the hypothesized FAP and LAP for the correct hypothesis and used for demodulation.

摘要翻译： 描述用于在接收机处执行时间跟踪的技术。 基于通信信道的信道脉冲响应估计来检测第一到达路径（FAP）和最后到达路径（LAP）。 检测到的FAP和LAP可能是正确的或交换的。 为了解决检测到的FAP和LAP中的歧义，评估了正确检测到对应于FAP和LAP的第一假设，以及对应于正确检测到的FAP和LAP的第二假说。 对于每个假设，基于检测到的FAP和LAP来确定假设的FAP和LAP，基于假设的FAP和LAP来确定相关窗口，并且使用相关窗口来执行相关性。 基于两个假设的相关结果确定正确的假设。 基于假设的FAP和LAP对于正确假设更新接收机定时并用于解调。

公开(公告)号：US07986922B2

公开(公告)日：2011-07-26

申请号：US11739971

申请日：2007-04-25

申请人： Serguei A. Glazko ,  James Edward Beckman ,  Shimman Patel

发明人： Serguei A. Glazko ,  James Edward Beckman ,  Shimman Patel

IPC分类号： H07Q7/20

CPC分类号： H04L27/2647 ,  H04B1/1036 ,  H04K3/228

摘要： Techniques for detecting and suppressing jammers are described. A receiver may perform post-FFT jammer detection and pre-FFT jammer suppression. The receiver may transform an input signal to obtain a frequency-domain signal and may detect for jammers in the input signal based on the frequency-domain signal. The receiver may determine powers of a plurality of carriers based on the frequency-domain signal and may detect for jammers based on peaks in the powers of these carriers. The receiver may filter the input signal (e.g., with a notch filter) to suppress the detected jammers. Alternatively or additionally, the receiver may perform post-FFT jammer detection and post-FFT jammer suppression. The receiver may determine whether jammer is present on each carrier based on data power and channel power for that carrier. The receiver may modify (e.g., zero out or reduce) the frequency-domain signal on carriers with detected jammers.

摘要翻译： 描述了用于检测和抑制干扰的技术。 接收机可以执行FFT后干扰检测和预FFT干扰抑制。 接收机可以变换输入信号以获得频域信号，并且可以基于频域信号来检测输入信号中的干扰。 接收机可以基于频域信号来确定多个载波的功率，并且可以基于这些载波的功率的峰值来检测干扰。 接收机可以过滤输入信号（例如，使用陷波滤波器）来抑制所检测到的干扰。 或者或另外，接收机可以执行FFT后干扰检测和FFT后干扰抑制。 接收机可以基于该载波的数据功率和信道功率来确定每个载波上是否存在干扰信号。 接收机可以利用检测到的干扰来修改（例如，零或降低）载波上的频域信号。

公开(公告)号：US07688882B2

公开(公告)日：2010-03-30

申请号：US11839504

申请日：2007-08-15

申请人： Roland R. Rick ,  Shimman Patel ,  Keith Saints ,  Haitao Zhang

发明人： Roland R. Rick ,  Shimman Patel ,  Keith Saints ,  Haitao Zhang

IPC分类号： H04B1/00

CPC分类号： H04B1/7085 ,  H04B1/7117 ,  H04B7/0697

摘要： An apparatus, such as a subscriber unit or a base station within a spread spectrum communication system, provides advanced control over the time-tracking of demodulation elements when unresolvable multipath situations arise. The apparatus provides merge protection that prevents clustered demodulation elements from contracting beyond a minimum time span. In addition, the apparatus provides a master/slave feature for synchronizing the time-tracking of the demodulation elements when clustered around a multipath signal.

摘要翻译： 在扩展频谱通信系统中的诸如用户单元或基站之类的装置在不可解决的多径情况出现时提供对解调元件的时间跟踪的高级控制。 该装置提供合并保护，防止聚集的解调元件超出最小时间间隔。 此外，该设备提供主/从功能，用于在聚集在多路径信号周围时同步解调元件的时间跟踪。

公开(公告)号：US20070140323A1

公开(公告)日：2007-06-21

申请号：US11313555

申请日：2005-12-20

申请人： Shimman Patel ,  Kuei-Chiang Lai ,  Seguei Glazko

发明人： Shimman Patel ,  Kuei-Chiang Lai ,  Seguei Glazko

IPC分类号： H04B1/00

CPC分类号： H04L27/2695 ,  H04L5/0048 ,  H04L25/022 ,  H04L25/0228 ,  H04L27/2613 ,  H04L27/2659 ,  H04L27/2662 ,  H04L27/3872 ,  H04L2027/0034 ,  H04L2027/0065

摘要： For frequency bin error estimation, multiple hypotheses are formed for different frequency bin errors, pilot offsets, or combinations of frequency bin error and pilot offset. For each hypothesis, received symbols are extracted from the proper subbands determined by the hypothesis. In one scheme, the extracted received symbols for each hypothesis are despread with a scrambling sequence to obtain despread symbols for that hypothesis. A metric is derived for each hypothesis based on the despread symbols, e.g., by deriving a channel impulse response estimate based on the despread symbols and then deriving the metric based on the channel impulse response estimate. In another scheme, the extracted received symbols for each hypothesis are correlated, and a metric is derived based on the correlation results. For both schemes, the frequency bin error and/or the pilot offset are determined based on the metrics for all hypotheses evaluated.

摘要翻译： 对于频率块误差估计，针对不同的频率误差，导频偏移或频率误差和导频偏移的组合形成多个假设。 对于每个假设，从由假设确定的适当子带中提取接收符号。 在一个方案中，每个假设的提取的接收符号用加扰序列解扩，以获得该假设的解扩符号。 基于解扩符号为每个假设导出度量，例如通过基于解扩符号导出信道脉冲响应估计，然后基于信道脉冲响应估计导出度量。 在另一方案中，将每个假设的提取的接收符号相关联，并且基于相关结果导出度量。 对于两种方案，基于所评估的所有假设的度量来确定频率块误差和/或导频偏移。

公开(公告)号：US07039138B2

公开(公告)日：2006-05-02

申请号：US09898537

申请日：2001-07-02

申请人： Shimman Patel ,  Thomas B. Wilborn

发明人： Shimman Patel ,  Thomas B. Wilborn

IPC分类号： H04B1/10 ,  H04B1/707

CPC分类号： H04B1/7097 ,  H04B2201/70701

摘要： A computationally efficient method and apparatus for estimating the bandwidth of a received signal. In an exemplary implementation, signal power within several selectably narrow frequency bands, each centered about a selected frequency, are calculated using only a relatively small number of arithmetic operations. Applications include using the estimated bandwidth to estimate the relative velocity between the transmitter and receiver, and modifying receiver operation based on such estimate.