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1. 发明授权

US07746760B2 Frequency error estimation and frame synchronization in an OFDM system 失效
标题翻译： OFDM系统中的频率误差估计和帧同步
公开(公告)号：US07746760B2
公开(公告)日：2010-06-29
申请号：US10754796
申请日：2004-01-08
申请人： Rajiv Vijayan , Alok Kumar Gupta , Raghuraman Krishnamoorthi
发明人： Rajiv Vijayan , Alok Kumar Gupta , Raghuraman Krishnamoorthi
IPC分类号： H04J11/00 , H04J3/06
CPC分类号： H04L27/2656 , H04L27/2657 , H04L27/2675
摘要： Frequency error estimation and frame synchronization are performed at a receiver in an OFDM system based on a metric that is indicative of detected pilot power. The metric may be defined based on cross-correlation between two received symbols obtained in two OFDM symbol periods. For frequency error estimation, a metric value is computed for each of multiple hypothesized frequency errors. The hypothesized frequency error for the metric value with the largest magnitude is provided as the estimated frequency error. For frame synchronization, a correlation value is obtained for each OFDM symbol period by correlating metric values obtained for NC (e.g., most recent) OFDM symbol periods with NC expected values. The expected values are computed in a manner consistent with the manner in which the metric values are computed. Peak detection is performed on the correlation values obtained for different OFDM symbol periods to determine frame synchronization.
摘要翻译：基于指示检测到的导频功率的度量，在OFDM系统中的接收机处执行频率误差估计和帧同步。可以基于在两个OFDM符号周期中获得的两个接收符号之间的互相关来定义度量。对于频率误差估计，针对多个假设的频率误差中的每一个计算度量值。提供具有最大幅度的度量值的假设频率误差作为估计的频率误差。对于帧同步，通过将为NC（例如，最近的）OFDM符号周期获得的度量值与NC预期值相关联，获得每个OFDM符号周期的相关值。以与计算度量值的方式一致的方式计算期望值。对针对不同的OFDM符号周期获得的相关值执行峰值检测以确定帧同步。

2. 发明申请

US20090190675A1 SYNCHRONIZATION IN A BROADCAST OFDM SYSTEM USING TIME DIVISION MULTIPLEXED PILOTS 审中-公开
标题翻译：使用时分多路复用器的广播OFDM系统中的同步
公开(公告)号：US20090190675A1
公开(公告)日：2009-07-30
申请号：US11933231
申请日：2007-10-31
申请人： Fuyun Ling , Alok Kumar Gupta , Raghuraman Krishnamoorthi , Ramaswamy Murali , Murali Ramaswamy Chari , Rajiv Vijayan , Bojan Vrcelj
发明人： Fuyun Ling , Alok Kumar Gupta , Raghuraman Krishnamoorthi , Ramaswamy Murali , Murali Ramaswamy Chari , Rajiv Vijayan , Bojan Vrcelj
IPC分类号： H04L27/28 , H04J3/06
CPC分类号： H04L27/2675 , H04L5/0007 , H04L5/0051 , H04L5/0064 , H04L7/042 , H04L25/0212 , H04L25/0216 , H04L25/0224 , H04L25/0226 , H04L27/2613 , H04L27/2656 , H04L27/2657 , H04L27/2662
摘要： In an OFDM system, a transmitter broadcasts a first TDM pilot on a first set of subbands followed by a second TDM pilot on a second set of subbands in each frame. The subbands in each set are selected from among N total subbands such that (1) an OFDM symbol for the first TDM pilot contains at least S1 identical pilot-1 sequences of length L1 and (2) an OFDM symbol for the second TDM pilot contains at least S2 identical pilot-2 sequences of length L2, where L2>L1, S1·L1=N, and S2·L2=N. The transmitter may also broadcast an FDM pilot. A receiver processes the first TDM pilot to obtain frame timing (e.g., by performing correlation between different pilot-1 sequences) and further processes the second TDM pilot to obtain symbol timing (e.g., by detecting for the start of a channel impulse response estimate derived from the second TDM pilot).
摘要翻译：在OFDM系统中，发射机在第一组子带上广播第一TDM导频，随后在每帧中的第二组子带上接收第二TDM导频。每个组中的子带从N个总子带中选出，使得（1）第一TDM导频的OFDM符号包含长度为L1的至少S1个相同的导频1序列，以及（2）第二TDM导频的OFDM符号包含至少S2个长度为L2的导频-2序列，其中L2> L1，S1.L1 = N，S2.L2 = N。发射机还可以广播FDM导频。接收机处理第一TDM导频以获得帧定时（例如，通过执行不同导频-1序列之间的相关）并且进一步处理第二TDM导频以获得符号定时（例如，通过检测导出的信道脉冲响应估计的开始从第二TDM导频）。

3. 发明授权

US09356752B2 Wide area and local network ID transmission for communication systems 有权
公开(公告)号：US09356752B2
公开(公告)日：2016-05-31
申请号：US12948759
申请日：2010-11-18
申请人： Michael Mao Wang , Bojan Vrcelj , Krishna Kiran Mukkavilli , Raghuraman Krishnamoorthi , Rajiv Vijayan
发明人： Michael Mao Wang , Bojan Vrcelj , Krishna Kiran Mukkavilli , Raghuraman Krishnamoorthi , Rajiv Vijayan
IPC分类号： H04L5/00 , H04L27/26
CPC分类号： H04L5/0048 , H04L5/0007 , H04L5/0083 , H04L27/261
摘要： The embodiments utilize OFDM symbols to communicate network IDs. The IDs are encoded into symbols utilizing the network IDs as seeds to scramble respective pilots that are then transmitted by utilizing the symbols. The pilots can be structured into a single OFDM symbol and/or multiple OFDM symbols. The single symbol structure for transmitting the network IDs is independent of the number of network ID bits and minimizes frequency offset and Doppler effects. The multiple symbol structure allows a much coarser timing accuracy to be employed at the expense of transmitting additional symbols. Several embodiments employ a search function to find possible network ID candidates from a transmitted symbol and a selection function to find an optimum candidate from a network ID candidate list.

4. 发明申请

US20130156124A1 SYSTEM AND METHOD FOR FREQUENCY DIVERSITY 有权
标题翻译：频域多样性的系统与方法
公开(公告)号：US20130156124A1
公开(公告)日：2013-06-20
申请号：US13767834
申请日：2013-02-14
申请人： Michael Mao Wang , Murali Ramaswamy Chari , Ashok Mantravadi , Fuyun Ling , Rajiv Vijayan , Raghuraman Krishnamoorthi
发明人： Michael Mao Wang , Murali Ramaswamy Chari , Ashok Mantravadi , Fuyun Ling , Rajiv Vijayan , Raghuraman Krishnamoorthi
IPC分类号： H04L27/26
CPC分类号： H04L27/2601 , H03M13/258 , H03M13/271 , H03M13/2957 , H03M13/31 , H04L1/0071 , H04L1/04 , H04L5/0007 , H04L5/0042 , H04L5/0044 , H04L5/0064 , H04L5/0083 , H04L27/2626 , H04L27/2634
摘要： A system and method for frequency diversity uses interleaving in a wireless communication system utilizing orthogonal frequency division multiplexing (OFDM) with various FFT sizes. Subcarriers of one or more interlaces are interleaved in a bit reversal fashion and the one or more interlaces are interleaved in the bit reversal fashion.
摘要翻译：用于频率分集的系统和方法使用利用具有各种FFT大小的正交频分复用（OFDM）的无线通信系统中的交织。一个或多个交错的子载波以位反向方式进行交织，并且该一个或多个交织以比特反转方式进行交织。

5. 发明授权

US08477809B2 Systems and methods for generalized slot-to-interlace mapping 有权
标题翻译：用于广义时隙到交错映射的系统和方法
公开(公告)号：US08477809B2
公开(公告)日：2013-07-02
申请号：US11834671
申请日：2007-08-06
申请人： Krishna Kiran Mukkavilli , Raghuraman Krishnamoorthi , Rajiv Vijayan
发明人： Krishna Kiran Mukkavilli , Raghuraman Krishnamoorthi , Rajiv Vijayan
IPC分类号： H04J3/06 , H04J9/00 , H04W4/00 , H04L27/28
CPC分类号： H04L5/0048 , H04L5/0007 , H04L5/0044 , H04L25/0224
摘要： A transmitter or receiver device includes a processing system configured to have one or more pilot interlace vectors and one or more distance vectors. The processing system is further configured to generate a first slot interlace for a first slot based on the one or more pilot interlace vectors, and is further configured to generate a second slot interlace for a second slot based on the first slot interlace and the one or more distance vectors. Additional slot interlaces for all other slots may also be generated based on the first slot interlace and the one or more distance vectors.
摘要翻译：发射机或接收机设备包括被配置为具有一个或多个导频交织向量和一个或多个距离向量的处理系统。所述处理系统还被配置为基于所述一个或多个导频交错向量来生成用于第一时隙的第一时隙交织，并且还被配置为基于所述第一时隙交织和所述第一时隙交织而生成用于第二时隙的第二时隙交织，更多距离矢量。也可以基于第一时隙交错和一个或多个距离矢量来生成用于所有其他时隙的附加时隙交织。

6. 发明申请

US20060215540A1 Efficient employment of digital upsampling using IFFT in OFDM systems for simpler analog filtering 有权
标题翻译：在OFDM系统中有效利用使用IFFT的数字上采样进行更简单的模拟滤波
公开(公告)号：US20060215540A1
公开(公告)日：2006-09-28
申请号：US11373001
申请日：2006-03-09
申请人： Raghuraman Krishnamoorthi , Fuyun Ling , Rajiv Vijayan
发明人： Raghuraman Krishnamoorthi , Fuyun Ling , Rajiv Vijayan
IPC分类号： H04J11/00
CPC分类号： H04L27/2644
摘要： Systems and methods are provided for transmitting OFDM information via IFFT up-sampling components that transmit data at a higher sampling rate than conventional systems to simplify filter requirements and mitigate leakage between symbols. In one embodiment, an NL point IFFT is performed on a zero inserted set of frequency domain symbols. In another embodiment, the NL point IFFT is further optimized by exploiting the fact that (N−1) L of the frequency domain symbols are zero. This enables an embodiment that consists of a pre-processor that multiplies the input samples by complex phase factors, followed by L point IFFTs.
摘要翻译：提供了系统和方法，用于通过IFFT上采样组件传输OFDM信息，该组件以比常规系统更高的采样速率传输数据，以简化滤波器要求并减轻符号之间的泄漏。在一个实施例中，对零插入的频域符号组执行NL点IFFT。在另一个实施例中，通过利用频域符号的（N-1）L为零的事实进一步优化NL点IFFT。这使得能够由预处理器组成的实施例，该预处理器将输入样本乘以复相位因子，随后是L点IFFT。

7. 发明申请

US20050063298A1 Synchronization in a broadcast OFDM system using time division multiplexed pilots 审中-公开
标题翻译：使用时分复用导频的广播OFDM系统中的同步
公开(公告)号：US20050063298A1
公开(公告)日：2005-03-24
申请号：US10931324
申请日：2004-08-31
申请人： Fuyun Ling , Alok Gupta , Raghuraman Krishnamoorthi , Ramaswamy Murali , Rajiv Vijayan , Bojan Vrcelj
发明人： Fuyun Ling , Alok Gupta , Raghuraman Krishnamoorthi , Ramaswamy Murali , Rajiv Vijayan , Bojan Vrcelj
IPC分类号： H04B3/10 , H04J20060101 , H04J1/16 , H04J11/00
CPC分类号： H04L27/2657 , H04L5/005 , H04L25/022 , H04L27/2613 , H04L27/2662 , H04L27/2665 , H04L2027/003
摘要： In an OFDM system, a transmitter broadcasts a first TDM pilot on a first set of subbands followed by a second TDM pilot on a second set of subbands in each frame. The subbands in each set are selected from among N total subbands such that (1) an OFDM symbol for the first TDM pilot contains at least S1 identical pilot-1 sequences of length L1 and (2) an OFDM symbol for the second TDM pilot contains at least S2 identical pilot-2 sequences of length L2, where L2>L1, S1·L1=N, and S2·L2=N. The transmitter may also broadcast an FDM pilot. A receiver processes the first TDM pilot to obtain frame timing (e.g., by performing correlation between different pilot-1 sequences) and further processes the second TDM pilot to obtain symbol timing (e.g., by detecting for the start of a channel impulse response estimate derived from the second TDM pilot).
摘要翻译：在OFDM系统中，发射机在第一组子带上广播第一TDM导频，随后在每帧中的第二组子带上接收第二TDM导频。每个组中的子带从N个总子带中选出，使得（1）第一TDM导频的OFDM符号包含长度为L1的至少S1个相同的导频1序列，以及（2）第二TDM导频的OFDM符号包含至少S2个长度为L2的导频-2序列，其中L2> L1，S1.L1 = N，S2.L2 = N。发射机还可以广播FDM导频。接收机处理第一TDM导频以获得帧定时（例如，通过执行不同导频-1序列之间的相关）并且进一步处理第二TDM导频以获得符号定时（例如，通过检测导出的信道脉冲响应估计的开始从第二TDM导频）。

8. 发明授权

US09042461B2 Efficient employment of digital upsampling using IFFT in OFDM systems for simpler analog filtering 有权
标题翻译：在OFDM系统中有效利用使用IFFT的数字上采样进行更简单的模拟滤波
公开(公告)号：US09042461B2
公开(公告)日：2015-05-26
申请号：US11373001
申请日：2006-03-09
申请人： Raghuraman Krishnamoorthi , Fuyun Ling , Rajiv Vijayan
发明人： Raghuraman Krishnamoorthi , Fuyun Ling , Rajiv Vijayan
IPC分类号： H04N7/18 , H04L27/26
CPC分类号： H04L27/2644
摘要： Systems and methods are provided for transmitting OFDM information via IFFT up-sampling components that transmit data at a higher sampling rate than conventional systems to simplify filter requirements and mitigate leakage between symbols. In one embodiment, an NL point IFFT is performed on a zero inserted set of frequency domain symbols. In another embodiment, the NL point IFFT is further optimized by exploiting the fact that (N−1) L of the frequency domain symbols are zero. This enables an embodiment that consists of a pre-processor that multiplies the input samples by complex phase factors, followed by L point IFFTs.
摘要翻译：提供了系统和方法，用于通过IFFT上采样组件传输OFDM信息，该组件以比常规系统更高的采样速率传输数据，以简化滤波器要求并减轻符号之间的泄漏。在一个实施例中，对零插入的频域符号组执行NL点IFFT。在另一个实施例中，通过利用频域符号的（N-1）L为零的事实进一步优化NL点IFFT。这使得能够由预处理器组成的实施例，该预处理器将输入样本乘以复相位因子，随后是L点IFFT。

9. 发明申请

US20060133388A1 Wide area and local network ID transmission for communication systems 有权
标题翻译：通信系统的广域和本地网络ID传输
公开(公告)号：US20060133388A1
公开(公告)日：2006-06-22
申请号：US11021310
申请日：2004-12-22
申请人： Michael Wang , Bojan Vrcelj , Krishna Mukkavilli , Raghuraman Krishnamoorthi , Rajiv Vijayan
发明人： Michael Wang , Bojan Vrcelj , Krishna Mukkavilli , Raghuraman Krishnamoorthi , Rajiv Vijayan
IPC分类号： H04L12/56
CPC分类号： H04L5/0048 , H04L5/0007 , H04L5/0083 , H04L27/261
摘要： The embodiments utilize OFDM symbols to communicate network IDs. The IDs are encoded into symbols utilizing the network IDs as seeds to scramble respective pilots that are then transmitted by utilizing the symbols. The pilots can be structured into a single OFDM symbol and/or multiple OFDM symbols. The single symbol structure for transmitting the network IDs is independent of the number of network ID bits and minimizes frequency offset and Doppler effects. The multiple symbol structure allows a much coarser timing accuracy to be employed at the expense of transmitting additional symbols. Several embodiments employ a search function to find possible network ID candidates from a transmitted symbol and a selection function to find an optimum candidate from a network ID candidate list.
摘要翻译：这些实施例利用OFDM符号来传送网络ID。 ID被编码成使用网络ID作为种子的符号，以对通过利用符号进行发送的各个导频进行加扰。导频可以被构造成单个OFDM符号和/或多个OFDM符号。用于发送网络ID的单个符号结构与网络ID比特数无关，并且使频偏和多普勒效应最小化。多符号结构允许以牺牲传输附加符号为代价采用更粗糙的定时精度。几个实施例采用搜索功能来从发送的符号和选择功能中找到可能的网络ID候选，以从网络ID候选列表中找到最佳候选。

10. 发明申请

US20050152326A1 Frequency error estimation and frame synchronization in an OFDM system 失效
标题翻译： OFDM系统中的频率误差估计和帧同步
公开(公告)号：US20050152326A1
公开(公告)日：2005-07-14
申请号：US10754796
申请日：2004-01-08
申请人： Rajiv Vijayan , Alok Gupta , Raghuraman Krishnamoorthi
发明人： Rajiv Vijayan , Alok Gupta , Raghuraman Krishnamoorthi
IPC分类号： H04L27/26 , H04J11/00
CPC分类号： H04L27/2656 , H04L27/2657 , H04L27/2675
摘要： Frequency error estimation and frame synchronization are performed at a receiver in an OFDM system based on a metric that is indicative of detected pilot power. The metric may be defined based on cross-correlation between two received symbols obtained in two OFDM symbol periods. For frequency error estimation, a metric value is computed for each of multiple hypothesized frequency errors. The hypothesized frequency error for the metric value with the largest magnitude is provided as the estimated frequency error. For frame synchronization, a correlation value is obtained for each OFDM symbol period by correlating metric values obtained for NC (e.g., most recent) OFDM symbol periods with NC expected values. The expected values are computed in a manner consistent with the manner in which the metric values are computed. Peak detection is performed on the correlation values obtained for different OFDM symbol periods to determine frame synchronization.
摘要翻译：基于指示检测到的导频功率的度量，在OFDM系统中的接收机处执行频率误差估计和帧同步。可以基于在两个OFDM符号周期中获得的两个接收符号之间的互相关来定义度量。对于频率误差估计，针对多个假设的频率误差中的每一个计算度量值。提供具有最大幅度的度量值的假设频率误差作为估计的频率误差。对于帧同步，通过将针对N N C C（例如，最近的）OFDM符号周期获得的度量值与N C 3期望值相关联，获得每个OFDM符号周期的相关值。以与计算度量值的方式一致的方式计算期望值。对针对不同的OFDM符号周期获得的相关值执行峰值检测以确定帧同步。

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