公开(公告)号：US08687510B1

公开(公告)日：2014-04-01

申请号：US12750531

申请日：2010-03-30

Applicant: Kedar Shirali ,  Ravi Narasimhan ,  Yungping Hsu

Inventor： Kedar Shirali ,  Ravi Narasimhan ,  Yungping Hsu

IPC: G01R31/08

CPC classification number: H04W28/0236 ,  H04L25/0206 ,  H04L25/0242 ,  H04W24/10 ,  H04W28/22

Abstract: Systems and techniques relating to processing a signal received over a wireless channel. A technique includes adaptively determining a data rate of packetized information transmission based on both a signal quality measure of a received signal and a channel quality measure derived from the received signal, the channel quality measure being indicative of frequency selectivity in the wireless channel. An apparatus includes a channel estimator configured to be responsive to a received OFDM signal corresponding to multiple frequency tones of the channel, and configured to evaluate channel response characteristics of the frequency tones; and a channel state indicator configured to generate a channel quality measure usable along with a signal quality measure in adaptively determining a data rate of packetized information transmission, wherein the channel quality measure is generated from the channel response characteristics of the frequency tones and is indicative of frequency selectivity in the wireless channel.

Abstract translation: 与处理通过无线信道接收的信号有关的系统和技术。 一种技术包括基于接收信号的信号质量测量和从接收信号导出的信道质量度量自适应地确定分组化信息传输的数据速率，信道质量度量指示无线信道中的频率选择性。 一种装置包括：信道估计器，被配置为响应于与所述信道的多个频率音调相对应的接收的OFDM信号，并且被配置为评估所述频率音调的信道响应特性; 以及信道状态指示符，其被配置为生成可自适应地确定分组化信息传输的数据速率的信号质量度量可用的信道质量度量，其中，信道质量度量是根据频率音调的信道响应特性产生的，并且指示 频率选择性在无线信道。

公开(公告)号：US08331502B1

公开(公告)日：2012-12-11

申请号：US13236036

申请日：2011-09-19

Applicant: Rohit Nabar ,  Kedar Shirali

Inventor： Rohit Nabar ,  Kedar Shirali

IPC: H04L27/06 ,  H04L27/28 ,  H04J11/00

CPC classification number: H04L25/0206 ,  H04L25/022 ,  H04L25/0224

Abstract: A method and apparatus for estimating a frequency response of a channel. The method includes adjusting phase components of estimates of the frequency response to provide phase-adjusted estimates; performing a smoothing operation on the phase-adjusted estimates to provide smoothed phase-adjusted estimates; and generating an output of a reverse phase adjustment, wherein the reverse phase adjustment is performed on the smoothed phase-adjusted estimates.

Abstract translation: 一种用于估计频道的频率响应的方法和装置。 该方法包括调整频率响应的估计的相位分量以提供相位调整的估计; 对经过调整后的估计进行平滑运算，以提供平滑的相位调整估计; 并产生反向相位调整的输出，其中对平滑的相位调整的估计执行反向相位调整。

公开(公告)号：US08218686B1

公开(公告)日：2012-07-10

申请号：US12420470

申请日：2009-04-08

Applicant: Sergey Timofeev ,  Atul Salhotra ,  Kedar Shirali ,  Srinivasa H. Garlapati

Inventor： Sergey Timofeev ,  Atul Salhotra ,  Kedar Shirali ,  Srinivasa H. Garlapati

IPC: H04L25/06 ,  H04L25/10

CPC classification number: H04L25/062 ,  H03D2200/0047

Abstract: An apparatus has front end circuitry to demodulate a radio frequency signal and to produce a baseband signal, the radio frequency signal being periodic and having a predetermined period. An analog-to-digital converter converts the baseband signal into a digital signal, the digital signal being periodic and having the predetermined period. A DC offset adjustment circuit includes a filter for estimating a DC offset contained in the digital signal based only on digital samples in a sample period having a length equal to the predetermined period. An adder removes the estimated DC offset from the digital signal. A method of operating such an apparatus is also disclosed.

Abstract translation: 一种装置具有用于解调射频信号并产生基带信号的前端电路，射频信号是周期性的并且具有预定周期。 模数转换器将基带信号转换为数字信号，数字信号是周期性的并且具有预定周期。 DC偏移调整电路包括用于仅在具有等于预定周期的长度的采样周期中的数字样本上估计包含在数字信号中的DC偏移的滤波器。 加法器从数字信号中去除估计的直流偏移。 还公开了一种操作这种装置的方法。

公开(公告)号：US07924930B1

公开(公告)日：2011-04-12

申请号：US11642442

申请日：2006-12-20

Applicant: Atul Salhotra ,  Kedar Shirali ,  Zhiyu Yang ,  Hui-Ling Lou

Inventor： Atul Salhotra ,  Kedar Shirali ,  Zhiyu Yang ,  Hui-Ling Lou

IPC: H04K1/10 ,  H04L27/28 ,  H04B7/02 ,  H04L1/02

CPC classification number: H04B7/0857 ,  H04B7/084 ,  H04L2025/03414 ,  H04L2025/03426

Abstract: A synchronization module for an orthogonal frequency-division multiplexing (OFDM) receiver system including a signal combination module that generates N combination signals that correspond to N received signals by performing at least one of weighted combining and selection and equal-gain-combining (EGC) on the N signals. A weighted signal generator module generates N weighted signals based on the N combination signals. N is an integer greater than one.

Abstract translation: 一种用于正交频分复用（OFDM）接收机系统的同步模块，包括信号组合模块，其通过执行加权组合和选择以及等增益组合（EGC）中的至少一个来产生对应于N个接收信号的N个组合信号， 对N信号。 加权信号发生器模块基于N个组合信号产生N个加权信号。 N是大于1的整数。

公开(公告)号：US20100232483A1

公开(公告)日：2010-09-16

申请号：US12785234

申请日：2010-05-21

Applicant: Hongyuan Zhang ,  Rohit U. Nabar ,  Kedar Shirali ,  Peter Loc

Inventor： Hongyuan Zhang ,  Rohit U. Nabar ,  Kedar Shirali ,  Peter Loc

IPC: H04B1/38 ,  H04L27/28

CPC classification number: H04B7/0413 ,  H04B7/0617 ,  H04B17/21 ,  H04L25/0204 ,  H04L25/0228 ,  H04L25/03343 ,  H04L2025/03414 ,  H04L2025/03426 ,  H04L2025/03802

Abstract: A first packet is transmitted via a forward channel corresponding to a signal direction from a first transceiver device to a second transceiver device, wherein the first packet includes a request to initiate calibration. A partial dimensional description of a reverse channel is determined based on the reception of a second packet received from the second transceiver device, wherein the second packet includes training information of spatial dimensions used for the transmission of the second packet but does not include training information for all available spatial dimensions of a reverse channel. A correction matrix is developed from the partial dimensional description of the reverse channel and a description of the forward channel, and the correction matrix and a steering matrix is used to process signals to be transmitted via the forward channel.

Abstract translation: 第一分组经由与从第一收发器设备到第二收发器设备的信号方向对应的前向信道发送，其中第一分组包括启动校准的请求。 基于从第二收发器设备接收到的第二分组的接收来确定反向信道的部分维度描述，其中第二分组包括用于传输第二分组的空间维度的训练信息，但不包括用于 反向通道的所有可用空间维度。 从反向信道的部分维度描述和正向信道的描述开发校正矩阵，并且使用校正矩阵和导引矩阵来处理要经由前向信道发送的信号。

公开(公告)号：US07729439B2

公开(公告)日：2010-06-01

申请号：US11857297

申请日：2007-09-18

Applicant: Hongyuan Zhang ,  Rohit U. Nabar ,  Kedar Shirali ,  Peter Loc

Inventor： Hongyuan Zhang ,  Rohit U. Nabar ,  Kedar Shirali ,  Peter Loc

IPC: H04B7/02 ,  H04L23/02 ,  H04B1/40

CPC classification number: H04B7/0413 ,  H04B7/0617 ,  H04B17/21 ,  H04L25/0204 ,  H04L25/0228 ,  H04L25/03343 ,  H04L2025/03414 ,  H04L2025/03426 ,  H04L2025/03802

Abstract: A transmitter beamforming technique for use in a MIMO wireless communication system determines a partial description of a reverse channel without determining a full dimensional description of the reverse channel. A correction matrix is developed from the partial description of the reverse channel and a description of the forward channel. The correction matrix is used to process signals to be transmitted via the forward channel, and a steering matrix is used to perform beamforming in the forward channel.

Abstract translation: 用于MIMO无线通信系统的发射机波束成形技术确定反向信道的部分描述，而不确定反向信道的全维度描述。 从反向信道的部分描述和正向信道的描述开发校正矩阵。 校正矩阵用于处理要经由正向信道发送的信号，并且使用导引矩阵来在前向信道中执行波束成形。

公开(公告)号：US07085330B1

公开(公告)日：2006-08-01

申请号：US10153554

申请日：2002-05-22

Applicant: Kedar Shirali

Inventor： Kedar Shirali

IPC: H04L25/03

CPC classification number: H04L27/368 ,  H03F1/3247 ,  H03F1/3282 ,  H03F3/24 ,  H03F2200/207 ,  H03F2201/3203

Abstract: A signal processing method and apparatus capable of correcting signal distortion introduced by an RF power amplifier is disclosed, which includes the use of a buffer to store a plurality of samples representing at least a portion of an input signal intended for amplification by the RF power amplifier, the use of a self-receiver to receive an output signal generated by the RF power amplifier, the use of a synchronization unit to determine, as a matching input sample, which of the stored plurality of samples corresponds most closely to the output signal, and the use of a predistortion unit to selectively apply a distortion correction function to the input signal prior to amplification by the RF power amplifier in which the distortion correction function being derived from a relationship between the matching input sample and the output signal. This permits more precise and updateable determination of the delays involved in the RF modulation and amplification stages of the amplifier and the self-receiver, thus allowing for more precise and aggressive adaptive predistortion to be used. A phase offset correction is optionally provided to correct a phase offset in the realized sample of the output signal relative to the matching input symbol. Additionally, a sampling phase error correction unit may be provided to generate sampling alteration information to an analog-to-digital converter to cause such analog-to-digital converter to selectively alter sampling of the output signal.

Abstract translation: 公开了一种能够校正由RF功率放大器引入的信号失真的信号处理方法和装置，其包括使用缓冲器来存储表示用于由RF功率放大器放大的输入信号的至少一部分的多个采样 使用自接收器接收由RF功率放大器产生的输出信号，使用同步单元确定所存储的多个样本中的哪一个最接近于输出信号的匹配输入样本， 以及使用预失真单元，在RF功率放大器进行放大之前，对输入信号选择性地应用失真校正功能，其中所述失真校正功能根据所述匹配输入采样与所述输出信号之间的关系导出。 这允许对放大器和自身接收机的RF调制和放大级中涉及的延迟的更精确和可更新的确定，从而允许使用更精确和积极的自适应预失真。 可选地提供相位偏移校正以校正输出信号相对于匹配输入符号的已实现采样中的相位偏移。 另外，可以提供采样相位误差校正单元以向模数转换器产生采样改变信息，以使得这种模数转换器有选择地改变输出信号的采样。

公开(公告)号：US08744023B1

公开(公告)日：2014-06-03

申请号：US11946707

申请日：2007-11-28

Applicant: Leilei Song ,  Rohit U. Nabar ,  Kedar Shirali

Inventor： Leilei Song ,  Rohit U. Nabar ,  Kedar Shirali

IPC: H04L1/00

CPC classification number: H04B15/02 ,  H04B1/10 ,  H04B7/0413 ,  H04L1/0054 ,  H04L1/06 ,  H04L1/20

Abstract: Systems and methods are provided for whitening noise of a received signal vector in a multiple-input multiple-output (MIMO) transmission or storage system. The whitening filter may be designed to whiten an interference component of the received signal vector, where the interference component is derived from modeling transmitter and receiver imperfections as a first coupling between MIMO transmitter outputs and a second coupling between MIMO receiver. The whitening filter may be computed based on the covariance matrix of the interference component.

Abstract translation: 提供了用于在多输入多输出（MIMO）传输或存储系统中对接收信号向量的噪声进行白化的系统和方法。 白化滤波器可以被设计为对接收信号矢量的干扰分量进行白化，其中干扰分量是从模拟发射机和接收机缺陷得到的，作为MIMO发射机输出与MIMO接收机之间的第二耦合的第一耦合。 可以基于干涉分量的协方差矩阵来计算白化滤波器。

公开(公告)号：US08571140B1

公开(公告)日：2013-10-29

申请号：US13605499

申请日：2012-09-06

Applicant: Konstantinos Sarrigeorgidis ,  Yanni Chen ,  Leilei Song ,  Kedar Shirali

Inventor： Konstantinos Sarrigeorgidis ,  Yanni Chen ,  Leilei Song ,  Kedar Shirali

IPC: H04L27/00

CPC classification number: H04L25/067 ,  H03M13/612 ,  H04L1/0045 ,  H04L25/03286 ,  H04L27/2647

Abstract: Methods and apparatus are provided for performing log-likelihood ratio (LLR) computations in a pipeline. Portions of a metric used to compute LLR values are computed in one pipeline part. The portions correspond to all permutations of some received signal streams. The portions are combined with one permutation x2 of the received signal stream that was not included in the previous pipeline computation in a subsequent pipeline part to produce M values associated with a particular bit position. At each subsequent clock cycle, a different permutation of x2 is combined with the previously computed portions producing different M values. State values corresponding to different values of bit positions of the received stream are computed by finding the minimum among the M values, in each clock cycle, that affect a particular bit position. The state values are combined to compute the LLR values for the bit position in a final pipeline part.

Abstract translation: 提供了在流水线中执行对数似然比（LLR）计算的方法和装置。 用于计算LLR值的度量的部分在一个管道部分中计算。 这些部分对应于一些接收的信号流的所有排列。 这些部分与接收信号流的一个置换x2组合在一起，该置换x2未被包括在随后的流水线部分中的先前流水线计算中，以产生与特定位位置相关联的M个值。 在每个随后的时钟周期，x2的不同置换与先前计算的产生不同M值的部分组合。 通过在每个时钟周期内找到影响特定位位置的M个值中的最小值来计算对应于接收流的比特位置的不同值的状态值。 组合状态值以计算最终流水线部分中位位置的LLR值。

公开(公告)号：US08275323B1

公开(公告)日：2012-09-25

申请号：US11827958

申请日：2007-07-13

Applicant: Kedar Shirali ,  Atul Salhotra ,  Zhiyu Yang

Inventor： Kedar Shirali ,  Atul Salhotra ,  Zhiyu Yang

IPC: H04B17/00

CPC classification number: H04W72/04 ,  H04B17/318 ,  H04W28/04 ,  H04W74/085

Abstract: A system including an activity sensing module to sense RF activity in first and second sub-channels of a communication channel of a first wireless network. N adjacent channel interference (ACI) filter modules arranged in parallel receive signals from N antennas, respectively, filter out signals in channels adjacent to the communication channel, and generate N filtered signals, respectively, where N>2. The activity sensing module generates control signals based on the N filtered signals. A channel identification module processes the control signals, and determines that both of the first and second sub-channels are available when the RF activity originating from a second wireless network is not present in both of the first and second sub-channels, and that the first sub-channel is available when the RF activity originating from the second wireless network is present only in the second sub-channel and is less than or equal to a predetermined threshold.

Abstract translation: 一种系统，包括用于感测第一无线网络的通信信道的第一和第二子信道中的RF活动的活动感测模块。 N个天线并行布置的N个相邻信道干扰（ACI）滤波器模块分别接收与通信信道相邻的信道中的信号，并分别产生N个滤波信号，其中N≥2。 活动感测模块根据N个滤波信号产生控制信号。 信道识别模块处理控制信号，并且当源自第二无线网络的RF活动不存在于第一和第二子信道中时，确定第一和第二子信道都可用，并且 当来自第二无线网络的RF活动仅在第二子信道中存在且小于或等于预定阈值时，第一子信道可用。