公开(公告)号：US20060203950A1

公开(公告)日：2006-09-14

申请号：US11358996

申请日：2006-02-21

申请人： Seong Chung ,  Vinay Murthy ,  Alok Gupta ,  Fuyun Ling

发明人： Seong Chung ,  Vinay Murthy ,  Alok Gupta ,  Fuyun Ling

IPC分类号： H03D3/24

CPC分类号： H03J7/04 ,  H03J1/0083

摘要： Techniques for performing frequency control using dual-loop automatic frequency control (AFC) are described. The dual-loop AFC includes an inner loop that corrects short-term frequency variations (e.g., due to Doppler effect) and an outer loop that corrects long-term frequency variations (e.g., due to component tolerances and temperature variations). In one design, a first inner loop is implemented for frequency control of a first system (e.g., a broadcast system), a second inner loop is implemented for frequency control of a second system (e.g., a cellular system), and at least one outer loop is implemented for adjusting a reference frequency used to receive signals from the first and second systems. Each inner loop estimates and corrects the frequency error in an input signal for the associated system and may be enabled when receiving the input signal from the system. The reference frequency may be used for frequency downconversion, sampling and/or other purposes.

公开(公告)号：US20060178755A1

公开(公告)日：2006-08-10

申请号：US11330652

申请日：2006-01-11

申请人： Fuyun Ling ,  Seong Chung ,  Jinxia Bai ,  Thomas Sun

发明人： Fuyun Ling ,  Seong Chung ,  Jinxia Bai ,  Thomas Sun

IPC分类号： G05B15/00

CPC分类号： H04L27/3488 ,  H04L1/0045 ,  H04L1/0065 ,  H04L1/0066 ,  H04L27/2604 ,  H04L2001/0098

摘要： A system and method are provided for generating bit log likelihood ratio (LLR) values for two-layered Quadrature Phase-Shift Keying (QPSK) turbo decoding in a wireless communications user terminal (UT). The method includes receiving a two-layered QPSK signal with an energy ratio that is unknown, but typically defined as either k12 or k22. The method selects a mismatched energy ratio (k2) between k12 and k22, and generating bit LLR values for two-layered QPSK turbo decoding, using the mismatched k2 energy ratio. For example, if the received two-layered QPSK signal is known to have an energy ratio of about 4 or about 6.25. Then, k2 is selected to be about 5.0625. Alternately stated, the mismatched k2 energy ratio in selected by determining the approximate midpoint between k12 and k22.

摘要翻译： 提供了一种用于在无线通信用户终端（UT）中生成用于双层正交相移键控（QPSK）turbo解码的比特对数似然比（LLR）值的系统和方法。 该方法包括以未知的能量比接收两层QPSK信号，但通常被定义为k1≤2或k2≥2。 该方法选择k1 <2> 2和k2 <2>之间的不匹配能量比（k <2> 2），并为双层QPSK涡轮增益产生位LLR值 使用不匹配的k <2>能量比进行解码。 例如，如果已知所接收的两层QPSK信号具有约4或约6.25的能量比。 然后，选择k <2>为约5.0625。 或者说，通过确定k1 <2> 2和k2 <2>之间的近似中点，所选择的不匹配的k 2 2能量比。

公开(公告)号：US20070217525A1

公开(公告)日：2007-09-20

申请号：US11376986

申请日：2006-03-15

申请人： Bojan Vrcelj ,  Raghuraman Krishnamoorthi ,  Seong Chung ,  Fuyun Ling

发明人： Bojan Vrcelj ,  Raghuraman Krishnamoorthi ,  Seong Chung ,  Fuyun Ling

IPC分类号： H04K1/10 ,  H04L27/06

CPC分类号： H04L27/2657 ,  H04L27/2607 ,  H04L27/2665 ,  H04L27/2678 ,  H04L27/2695

摘要： A frequency tracking method and apparatus is provided. A receiver receives OFDM symbols and determines associated frequency offset. A frequency error estimator selects a cross correlation window for determining frequency offset based on timing offset. A symbol timing estimator is used to determine the timing offset.

摘要翻译： 提供了一种频率跟踪方法和装置。 接收机接收OFDM符号并确定相关的频率偏移。 频率误差估计器基于定时偏移来选择用于确定频率偏移的互相关窗口。 使用符号定时估计器来确定定时偏移。

公开(公告)号：US20070179782A1

公开(公告)日：2007-08-02

申请号：US11557921

申请日：2006-11-08

申请人： Seong Chung ,  Krishna Mukkavilli ,  Vinay Murthy ,  Tao Tian

发明人： Seong Chung ,  Krishna Mukkavilli ,  Vinay Murthy ,  Tao Tian

IPC分类号： G10L19/14

CPC分类号： H04L27/2657 ,  H04L27/2675

摘要： Methods and apparatus for frequency tracking of a received signal. In an aspect, a method is provided wherein the received signal comprises one or more symbols having a periodic structure. The method comprises receiving a plurality of samples of a selected symbol that comprises pilot signals scrambled with data and determining a window size and a periodicity factor. The method also comprises accumulating a correlation between samples in a first window and samples in a second window to produce an accumulated correlation value, wherein the first and second windows have a size and a separation based on the window size and the periodicity factor, respectively, and deriving a frequency error estimate based on the accumulated correlation value.

摘要翻译： 接收信号频率跟踪的方法和装置。 在一方面，提供了一种方法，其中接收的信号包括具有周期性结构的一个或多个符号。 该方法包括：接收包含由数据加扰的导频信号和确定窗口大小和周期因子的所选符号的多个样本。 该方法还包括在第一窗口中累积样本之间的相关性并在第二窗口中采样以产生累加的相关值，其中第一和第二窗口分别具有基于窗口大小和周期性因子的大小和间隔， 以及基于所累积的相关值导出频率误差估计。

公开(公告)号：US20060171283A1

公开(公告)日：2006-08-03

申请号：US11329891

申请日：2006-01-10

申请人： Rajiv Vijayan ,  Seong Chung ,  Thomas Sun

发明人： Rajiv Vijayan ,  Seong Chung ,  Thomas Sun

IPC分类号： H01L21/66 ,  G11B3/74 ,  G01R31/26

CPC分类号： H04L27/3488 ,  H04L1/0045 ,  H04L1/005 ,  H04L1/0065 ,  H04L1/0066 ,  H04L1/007 ,  H04L27/2608 ,  H04L27/2626 ,  H04L27/2647 ,  H04L27/2649 ,  H04L2001/0098

摘要： A decoder for a layered modulation system can be configured to independently and concurrently decode each of a base and enhancement layer. The base layer decoder and enhancement layer decoder can be configured substantially in parallel and can each operate concurrently on the same received layered modulation symbol. Each of the base and enhancement layer decoders can be configured with a bit metric module that is configured to determine a signal quality metric based on the received symbol. In systems having turbo encoded data, the bit metric module can be configured to determine a log likelihood ratio. The ratio is based in part on a channel estimate and an energy ratio used in the layered modulation constellation.

摘要翻译： 用于分层调制系统的解码器可以被配置为独立地并且解码每个基本和增强层。 基本层解码器和增强层解码器可以基本并行配置，并且可以在相同的接收分层调制符号上同时操作。 基本和增强层解码器中的每一个可以配置有位度量模块，其被配置为基于接收到的符号来确定信号质量度量。 在具有turbo编码数据的系统中，比特量度模块可被配置为确定对数似然比。 该比率部分地基于在分层调制星座中使用的信道估计和能量比。

公开(公告)号：US20060183287A1

公开(公告)日：2006-08-17

申请号：US11330796

申请日：2006-01-11

申请人： Bruce Collins ,  Rajeev Krishnamurthi ,  Murali Chari ,  Shusheel Gautam ,  Rajiv Vijayan ,  Seong Chung

发明人： Bruce Collins ,  Rajeev Krishnamurthi ,  Murali Chari ,  Shusheel Gautam ,  Rajiv Vijayan ,  Seong Chung

IPC分类号： H01L21/8236

CPC分类号： H04L1/0065 ,  H04L1/0041 ,  H04L1/0045 ,  H04L1/0058 ,  H04L5/023 ,  H04L27/3488 ,  H04L2001/0098

摘要： A media access control (MAC) layer controller can manage base layer data and enhancement layer data in a layered modulation system. The MAC layer controller can process both base layer data and enhancement layer data and map the encoded symbols to a layered modulation constellation when both are present. If data for one of the layers terminates, then the MAC layer controller can generate and supply predetermined stuffing data to the layer lacking additional data. The MAC layer controller can send a control signal to the physical layer hardware to cause the hardware to map the layered signals having the stuffing data to a modified signal constellation. The MAC controller can also generate an overhead message that indicates the occurrence of the stuffing data. The receiver can receive the overhead message and can use the information to configure the receiver for the layered modulation constellation or the modified signal constellation.

公开(公告)号：US20060198454A1

公开(公告)日：2006-09-07

申请号：US11329717

申请日：2006-01-10

申请人： Seong Chung ,  Rajiv Vijayan

发明人： Seong Chung ,  Rajiv Vijayan

IPC分类号： H04K1/10

CPC分类号： H04L27/2601 ,  H04L25/0202 ,  H04L25/022 ,  H04L27/3488

摘要： Dynamic channel estimation thresholds allow for determining optimal threshold values for channel estimation in a layered-modulation wireless communication system. A channel estimation threshold can be used to remove or otherwise filter out channel estimate components that may be significantly influenced by noise. The channel estimation threshold value can be used to generate a refined channel estimate that is used in decoding multiple layers of a layered modulation signal. The channel estimation threshold value can be varied based on the performance of the various signal layer decoders. The adaptive channel estimation threshold provides for decoding a base layer based on an optimal threshold value for the base layer; determining an error rate associated with decoding the base layer; and using an optimal threshold value for an enhancement layer in a channel estimation algorithm if the error rate is lower than a predetermined level.

摘要翻译： 动态信道估计阈值允许确定分层调制无线通信系统中的信道估计的最佳阈值。 可以使用信道估计阈值来去除或以其他方式滤除可能受噪声显着影响的信道估计分量。 信道估计阈值可以用于生成用于解码分层调制信号的多个层的精细信道估计。 可以基于各种信号层解码器的性能来改变信道估计阈值。 自适应信道估计阈值基于用于基本层的最佳阈值来解码基本层; 确定与所述基本层解码相关联的错误率; 以及如果误差率低于预定水平，则在信道估计算法中对增强层使用最佳阈值。

公开(公告)号：US20060203710A1

公开(公告)日：2006-09-14

申请号：US11366779

申请日：2006-03-01

申请人： Krishna Mukkavilli ,  Kevin Cousineau ,  Seong Chung

发明人： Krishna Mukkavilli ,  Kevin Cousineau ,  Seong Chung

IPC分类号： H04J11/00

CPC分类号： H04L25/0232 ,  H04L25/0212 ,  H04L25/0216 ,  H04L25/022 ,  H04L25/025 ,  H04L27/2647

摘要： Channel estimation in a spectrally shaped wireless communication system in which an initial frequency response estimate is obtained for a first set of P uniformly spaced subbands (1) based on pilot symbols received on a second set of subbands used for pilot transmission and (2) using extrapolation and/or interpolation. A channel impulse response estimate is obtained by performing an IFFT on a frequency response estimate. The number of taps in the channel impulse response can be truncated to a predetermined number of taps determined based on an operating mode of the second set of P uniformly spaced subbands. The energy of each tap value remaining after truncation can be compared to a predetermined threshold and modified based on the results of the comparison. The predetermined threshold can be determined based on an operating mode. A final frequency response estimate for each mode within each OFDM symbol is derived.

摘要翻译： 在频谱形状的无线通信系统中的信道估计，其中基于在用于导频传输的第二组子带上接收的导频符号获得针对第一组P均匀间隔子带（1）的初始频率响应估计，以及（2）使用 外插和/或插值。 通过对频率响应估计执行IFFT来获得信道脉冲响应估计。 可以将信道脉冲响应中的抽头数量截断为基于第二组P均匀间隔子带的操作模式确定的预定数量的抽头。 截断后剩余的每个抽头值的能量可以与预定阈值进行比较，并根据比较结果进行修改。 可以基于操作模式来确定预定阈值。 导出每个OFDM符号内每个模式的最终频率响应估计。