公开(公告)号：US07583756B2

公开(公告)日：2009-09-01

申请号：US11761329

申请日：2007-06-11

Applicant: Parvathanathan Subrahmanya ,  Da-shan Shiu ,  Avneesh Agrawal

Inventor： Parvathanathan Subrahmanya ,  Da-shan Shiu ,  Avneesh Agrawal

IPC: H04L27/00 ,  H04B1/10 ,  H04L23/00

CPC classification number: H04L25/0228 ,  H04B1/7117 ,  H04B2201/70701 ,  H04L25/0214

Abstract: Techniques to filter pilot symbols for a pilot in an “adaptive” manner to provide an improved estimate of the response of a communication channel. A received signal may experience different channel conditions at different times, and different multipaths may also experience different channel conditions even when received close in time. A pilot filter with an adaptive response is used to provide an improved estimate of the channel response. Various adaptive pilot filtering schemes may be used. In a first scheme, the channel conditions are estimated based on the quality of the received pilot. In a second scheme, the channel conditions are estimated based on the quality of the pilot estimates (i.e., the filtered pilot symbols). For each scheme, a particular filter response is selected based on the estimated quality of either the received pilot or the pilot estimates.

Abstract translation: 用于以“自适应”方式滤波导频的导频符号以提供对通信信道的响应的改进估计的技术。 接收到的信号可能在不同时间经历不同的信道条件，即使在接收时间短的情况下，不同的多路径也可能经历不同的信道条件。 使用具有自适应响应的导频滤波器来提供信道响应的改进的估计。 可以使用各种自适应导频滤波方案。 在第一方案中，基于接收到的导频的质量来估计信道条件。 在第二方案中，基于导频估计的质量（即，滤波的导频符号）来估计信道条件。 对于每个方案，基于所接收的导频或导频估计的估计质量来选择特定的滤波器响应。

公开(公告)号：US20080310321A1

公开(公告)日：2008-12-18

申请号：US12196489

申请日：2008-08-22

Applicant: Francesco Grilli ,  Charles E. Wheatley, III ,  Serge Willenegger ,  Parvathanathan Subrahmanya

Inventor： Francesco Grilli ,  Charles E. Wheatley, III ,  Serge Willenegger ,  Parvathanathan Subrahmanya

IPC: H04B7/26 ,  H04B7/216 ,  G08C15/00

CPC classification number: H04W56/002 ,  H04B7/2668 ,  H04B2201/70702 ,  H04W56/001 ,  H04W56/0015 ,  H04W56/0045 ,  H04W92/20

Abstract: Schemes to time-align transmissions from multiple base stations to a terminal. To achieve time-alignment, differences between the arrival times of transmissions from the base stations, as observed at the terminal, are determined and provided to the system and used to adjust the timing at the base stations such that terminal-specific radio frames arrive at the terminal within a particular time window. In one scheme, a time difference between two base stations is partitioned into a frame-level time difference and a chip-level time difference. Whenever requested to perform and report time difference measurements, the terminal measures the chip-level timing for each candidate base station relative to a reference base station. Additionally, the terminal also measures the frame-level timing and includes this information in the time difference measurement only if required. Otherwise, the terminal sets the frame-level part to a predetermined value (e.g., zero).

Abstract translation: 将来自多个基站的传输时间对齐到终端的方案。 为了实现时间对准，确定在终端观察到的来自基站的传输的到达时间之间的差异，并将其提供给系统，并用于调整基站处的定时，使得终端专用无线帧到达 终端在特定的时间窗口内。 在一个方案中，两个基站之间的时差被划分为帧级时间差和码片级时间差。 无论何时请求执行和报告时差测量，终端测量每个候选基站相对于参考基站的芯片级定时。 此外，终端还测量帧级定时，并且仅在需要时在时差测量中包括该信息。 否则，终端将帧级部分设置为预定值（例如，零）。

公开(公告)号：US20080253487A1

公开(公告)日：2008-10-16

申请号：US11733646

申请日：2007-04-10

Applicant: Farrokh Abrishamkar ,  Mariam Motamed ,  Parvathanathan Subrahmanya

Inventor： Farrokh Abrishamkar ,  Mariam Motamed ,  Parvathanathan Subrahmanya

IPC: H04L1/20

CPC classification number: H04L25/0228

Abstract: Techniques for performing adaptive channel estimation are described. A receiver derives channel estimates for a wireless channel based on received pilot symbols and at least one estimation parameter. The receiver updates the at least one estimation parameter based on the received pilot symbols. The at least one estimation parameter may be for an innovations representation model of the wireless channel and may be updated based on a cost function with costs defined by prediction errors. In one design, the receiver derives predicted pilot symbols based on the received pilot symbols and the at least one estimation parameter, determines prediction errors based on the received pilot symbols and the predicted pilot symbols, and further derives error gradients based on the prediction errors. The receiver then updates the at least one estimation parameter based on the error gradients and the prediction errors, e.g., if a stability test is satisfied.

Abstract translation: 描述用于执行自适应信道估计的技术。 接收机基于接收的导频符号和至少一个估计参数导出无线信道的信道估计。 接收机基于接收的导频符号来更新至少一个估计参数。 所述至少一个估计参数可以是针对无线信道的创新表示模型，并且可以基于具有由预测误差定义的成本的成本函数来更新。 在一种设计中，接收器基于接收到的导频符号和至少一个估计参数导出预测的导频符号，基于接收到的导频符号和预测的导频符号来确定预测误差，并且还基于预测误差导出误差梯度。 然后，接收器基于误差梯度和预测误差来更新至少一个估计参数，例如，如果满足稳定性测试。

公开(公告)号：US20080117835A1

公开(公告)日：2008-05-22

申请号：US12019596

申请日：2008-01-24

Applicant: Francesco Grilli ,  Charles Wheatley ,  Serge Willenegger ,  Parvathanathan Subrahmanya

Inventor： Francesco Grilli ,  Charles Wheatley ,  Serge Willenegger ,  Parvathanathan Subrahmanya

IPC: G01R31/08

CPC classification number: H04W56/002 ,  H04B7/2668 ,  H04B2201/70702 ,  H04W56/001 ,  H04W56/0015 ,  H04W56/0045 ,  H04W92/20

Abstract: Schemes to time-align transmissions from multiple base stations to a terminal. To achieve time-alignment, differences between the arrival times of transmissions from the base stations, as observed at the terminal, are determined and provided to the system and used to adjust the timing at the base stations such that terminal-specific radio frames arrive at the terminal within a particular time window. In one scheme, a time difference between two base stations is partitioned into a frame-level time difference and a chip-level time difference. Whenever requested to perform and report time difference measurements, the terminal measures the chip-level timing for each candidate base station relative to a reference base station. Additionally, the terminal also measures the frame-level timing and includes this information in the time difference measurement only if required. Otherwise, the terminal sets the frame-level part to a predetermined value (e.g., zero).

公开(公告)号：US07376438B2

公开(公告)日：2008-05-20

申请号：US11249786

申请日：2005-10-12

Applicant: Da-shan Shiu ,  Serge Willenegger ,  Richard Chi ,  Parvathanathan Subrahmanya ,  Chih-Ping Hsu

Inventor： Da-shan Shiu ,  Serge Willenegger ,  Richard Chi ,  Parvathanathan Subrahmanya ,  Chih-Ping Hsu

IPC: H04B1/04 ,  H04B7/00 ,  H04Q7/20

CPC classification number: H04W52/12 ,  H04W52/20 ,  H04W52/267 ,  H04W52/283 ,  H04W52/286 ,  H04W52/44

Abstract: Techniques to more efficiently control the transmit power for a data transmission that uses a number of formats (e.g., rates, transport formats). Different formats for a given data channel (e.g., transport channel) may require different target SNIRs to achieved a particular BLER. In one aspect, individual target BLER may be specified for each format of each data channel. In another aspect, various power control schemes are provided to achieve different target SNIRs for different formats. In a first power control scheme, multiple individual outer loops are maintained for multiple formats. For each format, its associated outer loop attempts to set the target SNIR such that the target BLER specified for that format is achieved. In a second power control scheme, multiple individual outer loops are maintained and the base station further applies different adjustments to the transmit power levels for different formats.

Abstract translation: 用于更有效地控制使用多种格式（例如，速率，传输格式）的数据传输的发射功率的技术。 给定数据信道（例如，传输信道）的不同格式可能需要不同的目标SNIR来实现特定的BLER。 在一个方面，可以为每个数据信道的每个格式指定单个目标BLER。 在另一方面，提供各种功率控制方案以实现用于不同格式的不同目标SNIR。 在第一功率控制方案中，为多种格式维护多个单独的外环。 对于每个格式，其关联的外部循环尝试设置目标SNIR，使得为该格式指定的目标BLER被实现。 在第二功率控制方案中，保持多个单独的外环，并且基站进一步对不同格式的发射功率电平进行不同的调整。

公开(公告)号：US20070110127A1

公开(公告)日：2007-05-17

申请号：US11399886

申请日：2006-04-07

Applicant: Gokhan Mergen ,  Vignesh Sethuraman ,  Nitin Kasturi ,  Parvathanathan Subrahmanya

Inventor： Gokhan Mergen ,  Vignesh Sethuraman ,  Nitin Kasturi ,  Parvathanathan Subrahmanya

IPC: H04B1/00 ,  H04L27/06 ,  H04B1/10

CPC classification number: H04L25/0216 ,  H04L25/0218

Abstract: Techniques for deriving a channel impulse response estimate (CIRE) having improved quality are described. A first CIRE with multiple channel taps is obtained based on (1) an initial CIRE derived from a received pilot or (2) a filtered CIRE derived from the initial CIRE. In one aspect, the channel taps in the first CIRE are scaled with multiple scaling factors to obtain a second CIRE. For point-wise LMMSE scaling, the energy of each channel tap is estimated. The noise energy for the channel taps is also estimated, e.g., based on energies of channel taps on one or both edges of the first CIRE. Each channel tap is scaled based on a scaling factor determined by the energy of that channel tap and the noise energy. Each channel tap with energy below a threshold may be set to zero. In another aspect, the second CIRE is obtained by zeroing out selected ones of the channel taps in the first CIRE.

Abstract translation: 描述了用于导出具有改进的质量的信道脉冲响应估计（CIRE）的技术。 基于（1）从接收到的导频导出的初始CIRE或（2）从初始CIRE导出的滤波CIRE，获得具有多信道抽头的第一CIRE。 在一个方面，第一CIRE中的信道抽头被多个缩放因子缩放以获得第二CIRE。 对于逐点LMMSE缩放，估计每个通道抽头的能量。 也可以例如基于第一CIRE的一个或两个边缘上的信道抽头的能量来估计信道抽头的噪声能量。 每个通道抽头基于由该通道抽头的能量和噪声能量确定的缩放因子进行缩放。 能量低于阈值的每个通道抽头可以设置为零。 在另一方面，第二CIRE是通过对第一CIRE中的选通的信道抽头进行归零而获得的。

公开(公告)号：US20070098051A1

公开(公告)日：2007-05-03

申请号：US11392316

申请日：2006-03-28

Applicant: Thejaswi Bharadwaj Shesha ,  Brian Dong ,  Messay Amerga ,  Chih-Ping Hsu ,  Parvathanathan Subrahmanya ,  Xiaoming Zhu

Inventor： Thejaswi Bharadwaj Shesha ,  Brian Dong ,  Messay Amerga ,  Chih-Ping Hsu ,  Parvathanathan Subrahmanya ,  Xiaoming Zhu

IPC: H04B1/00

CPC classification number: H04B1/7117 ,  B60L2200/26

Abstract: A rake receiver finger assignor is configured to assign a rake receiver finger to a time offset between identified signal path time offsets in accordance with a concentration of identified signal paths from a transmitter to a rake receiver. In accordance with the exemplary embodiment, a number of identified signal paths having time offsets within a time window are observed to determine the concentration of signal paths identified by a path searcher. If the number of identified signal paths indicates a concentrated distribution of signal paths such as during a fat path condition, at least one rake finger is assigned between at a time offset between two identified signal paths.

Abstract translation: 耙式接收器手指分配器被配置为根据从发射机到耙式接收机的识别的信号路径的浓度，将耙机接收机手指分配到所识别的信号路径时间偏移之间的时间偏移。 根据示例性实施例，观察到在时间窗内具有时间偏移的多个识别的信号路径，以确定由路径搜索器识别的信号路径的浓度。 如果所识别的信号路径的数量表示信号路径的集中分布，例如在脂肪路径条件期间，则在两个识别的信号路径之间的时间偏移处分配至少一个耙指。

公开(公告)号：US20070060095A1

公开(公告)日：2007-03-15

申请号：US11228045

申请日：2005-09-15

Applicant: Parvathanathan Subrahmanya ,  Thejaswi Bharadwaj Madapushi Sheshadri ,  Vivek Chawla

Inventor： Parvathanathan Subrahmanya ,  Thejaswi Bharadwaj Madapushi Sheshadri ,  Vivek Chawla

IPC: H04B1/16 ,  H04B1/38 ,  H04M1/00

CPC classification number: H04L27/2278 ,  H04B1/7085 ,  H04B2201/70709 ,  H04L2027/003 ,  H04L2027/0034 ,  H04L2027/0065 ,  H04W52/0229 ,  Y02D70/122 ,  Y02D70/1242 ,  Y02D70/166 ,  Y02D70/24 ,  Y02D70/40

Abstract: Quick frequency tracking (QFT), quick time tracking (QTT), and non-causal pilot filtering (NCP) are used to detect sporadically transmitted signaling, e.g., paging indicators. For QFT, multiple hypothesized frequency errors are applied to an input signal to obtain multiple rotated signals. The energies of the rotated signals are computed. The hypothesized frequency error with the largest energy is provided as a frequency error estimate. For QTT, coherent accumulation is performed on the input signal for a first set of time offsets, e.g., early, on-time, and late. Interpolation, energy computation, and non-coherent accumulation are then performed to obtain a timing error estimate with higher time resolution. For NCP, pilot symbols are filtered with a non-causal filter to obtain pilot estimates for one antenna for non-STTD and for two antennas for STTD. The frequency and timing error estimates and the pilot estimates are used to detect the signaling.

Abstract translation: 使用快速频率跟踪（QFT），快速时间跟踪（QTT）和非因果导频滤波（NCP）来检测偶发地发送的信令，例如寻呼指示符。 对于QFT，将多个假设频率误差应用于输入信号以获得多个旋转信号。 计算旋转信号的能量。 提供具有最大能量的假设频率误差作为频率误差估计。 对于QTT，对于第一组时间偏移的输入信号执行相干累加，例如早，时，晚。 然后执行插值，能量计算和非相干累加，以获得具有更高时间分辨率的定时误差估计。 对于NCP，使用非因果滤波器对导频符号进行滤波，以获得用于非STTD的一个天线和用于STTD的两个天线的导频估计。 频率和定时误差估计和导频估计用于检测信令。

公开(公告)号：US07155177B2

公开(公告)日：2006-12-26

申请号：US10364638

申请日：2003-02-10

Applicant: Jittra Jootar ,  Da-shan Shiu ,  Parvathanathan Subrahmanya

Inventor： Jittra Jootar ,  Da-shan Shiu ,  Parvathanathan Subrahmanya

IPC: H04B1/02 ,  H04B17/00 ,  H04B1/10

CPC classification number: H04B7/0634

Abstract: Techniques for predicting weights used for closed-loop transmit diversity. In a channel prediction scheme, channel gains for multiple transmit antennas are initially estimated (e.g., based on pilots received from these antennas) and used to derive predicted channel gains for a future time instant. The predicted channel gains are then used to derive predicted weights that are deemed to be “optimal” at the future time instant. Optimality may be determined based on one or more criteria, such as maximizing a received SNR for the received signals. In a weight prediction scheme, the channel gains for the multiple antennas are estimated and used to compute optimal weights for the current time instant. The current optimal weights are then used to predict the optimal weights at the future time instant. For both schemes, the prediction may be performed based on an adaptive filter (e.g., LMS or RLS filter) or a non-adaptive filter.

Abstract translation: 用于预测用于闭环发射分集的权重的技术。 在信道预测方案中，最初估计多个发射天线的信道增益（例如，基于从这些天线接收的导频），并用于在未来时刻导出预测的信道增益。 然后，预测的信道增益用于导出在未来时刻被认为是“最佳”的预测权重。 可以基于一个或多个准则来确定最优性，例如为接收到的信号最大化接收到的SNR。 在权重预测方案中，估计多个天线的信道增益并用于计算当前时刻的最优权重。 然后使用当前的最优权重来预测未来时刻的最优权重。 对于这两种方案，可以基于自适应滤波器（例如，LMS或RLS滤波器）或非自适应滤波器来执行预测。

公开(公告)号：US20050249149A1

公开(公告)日：2005-11-10

申请号：US10841299

申请日：2004-05-07

Applicant: Nitin Kasturi ,  Parvathanathan Subrahmanya

Inventor： Nitin Kasturi ,  Parvathanathan Subrahmanya

IPC: H04B7/005 ,  H04W52/22 ,  H04W52/36 ,  H04Q7/00

CPC classification number: H04W52/221 ,  H04W52/146 ,  H04W52/367

Abstract: Techniques to mitigate spikes in transmit power, by reducing the magnitude and/or duration of the spikes, are described. Initially, power control is performed in a normal manner and in accordance with a transmit power control (TPC) scheme. If a (e.g., upward) transmit power spike is detected, the power control is performed in a manner to mitigate the adverse effects of the spike and in accordance with another TPC scheme. An upward transmit power spike may be detected, e.g., if a predetermined number of consecutive TPC commands in the upward direction is obtained for increasing transmit power. The upward transmit power spike may be mitigated by limiting the transmit power, reducing the rate of transmit power adjustment in the upward direction, delaying and/or filtering TPC decisions used for transmit power adjustment, preventing upward adjustment of transmit power, and so on. Multiple states may be defined and used to facilitate power control with spike mitigation.

Abstract translation: 描述了通过减小​​尖峰的幅度和/或持续时间来减轻发射功率尖峰的技术。 最初，按照发送功率控制（TPC）方式，以正常的方式进行功率控制。 如果检测到（例如，向上）发射功率尖峰，则以减轻尖峰的不利影响并根据另一TPC方案的方式执行功率控制。 可以检测向上的发送功率尖峰，例如，如果获得了向上方向上的预定数量的连续TPC命令以增加发射功率。 通过限制发射功率，降低向上方向的发射功率调整速率，延迟和/或滤波用于发射功率调整的TPC决定，防止发射功率的向上调整等，可以减轻向上发射功率尖峰。 多个状态可以被定义并用于通过尖峰减轻来促进功率控制。