公开(公告)号：US20080165908A1

公开(公告)日：2008-07-10

申请号：US11765428

申请日：2007-06-19

Applicant: Bojan Vrcelj ,  Krishna Kiran Mukkavilli ,  Ashok Mantravadi ,  Raghuraman Krishnamoorthi

Inventor： Bojan Vrcelj ,  Krishna Kiran Mukkavilli ,  Ashok Mantravadi ,  Raghuraman Krishnamoorthi

IPC: H04L7/00

CPC classification number: H04L27/2662 ,  H04L5/0048 ,  H04L7/08 ,  H04L25/0216 ,  H04L25/023 ,  H04L27/2613 ,  H04L27/2675 ,  H04L27/2695

Abstract: Methods and apparatus for timing synchronization based on transitional pilot symbols. In an aspect, a method is provided for time tracking synchronization in an OFDM system. The method includes receiving at least one TDM pilot symbol comprising a plurality of modulated sub-carriers that are configured to provide a channel estimate having a length that extends up to a duration of an FFT used for data transmission. The method also includes determining one or both of an instantaneous and averaged channel estimates from the plurality of modulated sub-carriers, and calculating a timing offset based on one or both of the channel estimates. An apparatus includes a receiver configured to receive the at least one TDM pilot symbol, a channel estimator configured to determine the instantaneous and averaged channel estimates, and a time synchronizer configured to calculate a timing offset based on the channel estimates.

Abstract translation: 基于过渡导频符号的定时同步的方法和装置。 在一方面，提供了一种用于OFDM系统中的时间跟踪同步的方法。 该方法包括接收至少一个TDM导频符号，该TDM导频符号包括多个经调制的子载波，其被配置为提供具有延伸到用于数据传输的FFT的持续时间的长度的信道估计。 该方法还包括确定来自多个调制子载波的瞬时和平均信道估计中的一个或两个，以及基于信道估计中的一个或两个来计算定时偏移。 一种装置包括被配置为接收所述至少一个TDM导频符号的接收机，被配置为确定瞬时和平均信道估计的信道估计器，以及被配置为基于信道估计来计算定时偏移的时间同步器。

公开(公告)号：US20230064912A1

公开(公告)日：2023-03-02

申请号：US17797061

申请日：2020-04-03

Applicant: Jing LEI ,  Chao WEI ,  Wanshi CHEN ,  Huilin XU ,  Peter Pui Lok ANG ,  Peter GAAL ,  Hwan Joon KWON ,  Krishna Kiran MUKKAVILLI ,  Tingfang JI ,  QUALCOMM Incorporated

Inventor： Jing LEI ,  Chao WEI ,  Wanshi CHEN ,  Huilin XU ,  Peter Pui Lok ANG ,  Peter GAAL ,  Hwan Joon KWON ,  Krishna Kiran MUKKAVILLI ,  Tingfang JI

IPC: H04L1/08 ,  H04W72/04

Abstract: Aspects of the present disclosure include methods, apparatuses, and computer readable media for generating a first scrambling identification (ID), generating a first scrambling sequence based on the first scrambling ID, scrambling a first set of information based on the first scrambling sequence to generate a first plurality of information bits, generating a plurality of repeated copies of the first plurality of information bits scrambled using the first scrambling sequence, and transmitting a first transmission burst including each of the plurality of repeated copies of the first plurality of information bits on different ones of a first plurality of resources in a communication channel.

公开(公告)号：US09356752B2

公开(公告)日：2016-05-31

申请号：US12948759

申请日：2010-11-18

Applicant: Michael Mao Wang ,  Bojan Vrcelj ,  Krishna Kiran Mukkavilli ,  Raghuraman Krishnamoorthi ,  Rajiv Vijayan

Inventor： Michael Mao Wang ,  Bojan Vrcelj ,  Krishna Kiran Mukkavilli ,  Raghuraman Krishnamoorthi ,  Rajiv Vijayan

IPC: H04L5/00 ,  H04L27/26

CPC classification number: H04L5/0048 ,  H04L5/0007 ,  H04L5/0083 ,  H04L27/261

Abstract: 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.

公开(公告)号：US08855655B2

公开(公告)日：2014-10-07

申请号：US12176376

申请日：2008-07-20

Applicant: Binita Gupta ,  Krishna Kiran Mukkavilli ,  Ashok Mantravadi ,  Raghuraman Krishnamoorthi

Inventor： Binita Gupta ,  Krishna Kiran Mukkavilli ,  Ashok Mantravadi ,  Raghuraman Krishnamoorthi

IPC: H04W40/00 ,  H04W36/00

CPC classification number: H04W28/18 ,  H04W48/08

Abstract: Methods and apparatus for signaling parameter distribution for neighboring radio frequencies. A method includes identifying selected local operations infrastructures (LOIs) and one or more neighboring LOIs, generating a neighbor description message (NDM) that identifies the selected LOIs and their respective neighbors and specifies SP information for each RF channel associated with the selected LOIs and their respective neighbors, and distributing the NDM over each of the selected LOIs. An apparatus includes a message decoder configured to receive a NDM that identifies RF channels associated with selected LOIs and one or more neighboring LOIs, wherein each RF channel is associated with SP information, and processing logic configured to receive a request to obtain selected SP information associated with a selected RF channel, determine the selected SP information associated with the selected RF channel based on the NDM, and output the selected SP information.

Abstract translation: 用于信号参数分配的相邻射频的方法和装置。 一种方法包括识别所选择的本地操作基础设施（LOI）和一个或多个相邻LOI，生成标识所选择的LOI及其相应邻居的邻居描述消息（NDM），并且为与所选择的LOI相关联的每个RF信道指定SP信息， 并且在每个所选择的LOI上分发NDM。 一种装置包括消息解码器，其被配置为接收标识与所选择的LOI和一个或多个相邻LOI相关联的RF信道的NDM，其中每个RF信道与SP信息相关联，以及处理逻辑，被配置为接收获取所选择的SP信息的请求 利用所选择的RF信道，基于NDM确定与所选择的RF信道相关联的所选择的SP信息，并输出所选择的SP信息。

公开(公告)号：US08509325B2

公开(公告)日：2013-08-13

申请号：US12250135

申请日：2008-10-13

Applicant: Ashok Mantravadi ,  Krishna Kiran Mukkavilli ,  Raghuraman Krishnamoorthi ,  Rajeev Krishnamurthi

Inventor： Ashok Mantravadi ,  Krishna Kiran Mukkavilli ,  Raghuraman Krishnamoorthi ,  Rajeev Krishnamurthi

IPC: H04L27/28

CPC classification number: H04L25/0218 ,  H04L5/0007 ,  H04L25/0204 ,  H04L25/022 ,  H04L25/0224

Abstract: An adaptive thresholding technique eliminates suboptimum threshold values by adjusting for varying channel conditions to eliminate interference where no channel energy is present, without discarding viable taps having useful channel energy. The adaptive thresholding technique adaptively optimizes receive threshold values for both wide and local area channels based only on measured C/I ratios 300. Thresholds are calculated based on instantaneous C/I estimates and/or weighted average C/I estimates calculated from WID/LID energies obtained from the current superframe WIC/LIC symbols respectively. In alternate embodiments, thresholds are calculated based on instantaneous C/I estimates and/or weighted average C/I estimates calculated from WTPC and LTPC symbols for the wide and local area channels, respectively The present adaptive thresholding technique dynamically reduces the threshold as the C/I estimate increases to mitigate performance degradation due to removal of weak signal taps. There is a separate threshold for each of the 12 coding and modulation modes supported by an exemplary receiver.

Abstract translation: 自适应阈值技术通过调整不同的信道条件来消除次优阈值，以消除不存在信道能量的干扰，而不丢弃具有有用信道能量的可行分接头。 自适应阈值技术仅基于测量的C / I比300自适应地优化宽和局域信道的接收阈值。阈值基于从WID / LID计算的瞬时C / I估计和/或加权平均C / I估计来计算 从当前超帧WIC / LIC符号获得的能量。 在替代实施例中，基于针对宽和局域信道的WTPC和LTPC符号计算的瞬时C / I估计和/或加权平均C / I估计来计算阈值。当前自适应阈值技术动态地将阈值设置为C /我估计增加以减轻由于去除弱信号抽头而导致的性能下降。 对于由示例性接收机支持的12个编码和调制模式中的每一个，存在单独的阈值。

公开(公告)号：US08144818B2

公开(公告)日：2012-03-27

申请号：US11303487

申请日：2005-12-15

Applicant: Krishna Kiran Mukkavilli ,  Michael Mao Wang ,  Raghuraman Krishnamoorthi

Inventor： Krishna Kiran Mukkavilli ,  Michael Mao Wang ,  Raghuraman Krishnamoorthi

IPC: H03D1/00

CPC classification number: H04L27/2662 ,  H04L25/0202 ,  H04L27/2686

Abstract: Apparatus and methods for use in a wireless communication system are disclosed for determining a timing position for channel activity in order to resolve timing ambiguity. A disclosed apparatus includes a processor that determines when channel activity occurs in at least one of an early or a late arrival position in a communication channel estimate and unwraps the channel activity in either the early arrival position or the late arrival position to a corresponding late or early arrival unwrapped channel activity position in the wireless channel estimate. The processor correlates symbol data in the communication signal corresponding to both the channel activity and the unwrapped channel activity to symbol data of the main channel activity. The processor determines whether a correct timing position of the channel activity is one of the early or late arrival positions based on the correlations, thus resolving timing ambiguity. Complementary methods are also disclosed.

Abstract translation: 公开了用于无线通信系统中的装置和方法，用于确定信道活动的定时位置，以便解决定时模糊。 所公开的装置包括处理器，其确定在通信信道估计中的早期或迟到到达位置中的至少一个中何时发生信道活动，并且将早期到达位置或延迟到达位置中的信道活动解包到相应的延迟或 在无线信道估计中提前到达解开的频道活动位置。 处理器将对应于信道活动和解开的信道活动的通信信号中的符号数据与主信道活动的符号数据相关联。 处理器基于相关性确定信道活动的正确定时位置是早期还是迟到位置之一，从而解决定时模糊度。 还公开了互补方法。

公开(公告)号：US08102756B2

公开(公告)日：2012-01-24

申请号：US11834669

申请日：2007-08-06

Applicant: Krishna Kiran Mukkavilli ,  Ashok Mantravadi ,  Raghuraman Krishnamoorthi ,  Murali Ramaswamy Chari ,  Tao Tian

Inventor： Krishna Kiran Mukkavilli ,  Ashok Mantravadi ,  Raghuraman Krishnamoorthi ,  Murali Ramaswamy Chari ,  Tao Tian

IPC: H04J11/00 ,  H04Q7/00

CPC classification number: H04W48/16 ,  H04L27/2647

Abstract: A method of acquiring a forward link only (FLO) network in a radio frequency (RF) in a wireless communication environment, includes selecting a RF from a first list; selecting a signal parameter (SP) from a second list; determining if a first parameter is found using the selected RF and SP; and, upon determination that the first parameter is found, enabling the use of the selected RF and SP to communicate in the FLO network. An apparatus for implementing the method is also disclosed.

Abstract translation: 一种在无线通信环境中在射频（RF）中获取前向链路（FLO）网络的方法，包括从第一列表中选择RF; 从第二列表中选择信号参数（SP）; 使用所选择的RF和SP确定是否发现第一参数; 并且在确定发现第一参数之后，使所选择的RF和SP能够在FLO网络中进行通信。 还公开了一种用于实现该方法的装置。

公开(公告)号：US07907593B2

公开(公告)日：2011-03-15

申请号：US12254680

申请日：2008-10-20

Applicant: Rajiv Vijayan ,  Ashok Mantravadi ,  Krishna Kiran Mukkavilli

Inventor： Rajiv Vijayan ,  Ashok Mantravadi ,  Krishna Kiran Mukkavilli

IPC: H04J3/06

CPC classification number: H04L25/022 ,  H04L5/0048 ,  H04L23/02 ,  H04L25/0212 ,  H04L25/0228 ,  H04L27/2662 ,  H04L27/2695

Abstract: To allow a receiving entity to derive a longer channel estimate while limiting overhead, a transmitting entity transmits a pilot on different groups of subbands in different time intervals. N subbands in the system are arranged into M non-overlapping groups. Each group includes P=N/M subbands that are uniformly distributed across the N subbands. The transmitting entity transmits the pilot on a different subband group in each time interval, and selects all M subband groups in M time intervals based on a pilot staggering pattern. The receiving entity derives (1) an initial impulse response estimate with P channel taps based on the pilot received on one subband group and (2) two longer impulse response estimates with different lengths used for data detection and time tracking. Each longer impulse response estimate may be derived by filtering initial impulse response estimates for a sufficient number of subband groups using a time-domain filter.

Abstract translation: 为了允许接收实体在限制开销的同时导出更长的信道估计，发送实体以不同的时间间隔在不同的子带组上发送导频。 系统中的N个子带被布置成M个非重叠组。 每组包括均匀分布在N个子带上的P = N / M个子带。 发送实体在每个时间间隔中在不同子带组上发送导频，并且基于导频交错模式以M个时间间隔选择所有M个子带组。 接收实体基于在一个子带组上接收到的导频导出（1）具有P信道抽头的初始脉冲响应估计，以及（2）用于数据检测和时间跟踪的两个具有不同长度的较长脉冲响应估计。 可以通过使用时域滤波器对足够数量的子带组的初始脉冲响应估计进行滤波来导出更长的脉冲响应估计。

公开(公告)号：US20100316044A1

公开(公告)日：2010-12-16

申请号：US12862740

申请日：2010-08-24

Applicant: Bojan VRCELJ ,  Ashok Mantravadi ,  Fuyun Ling ,  Krishna Kiran Mukkavilli ,  Raghuraman Krishnamoorthi ,  Michael Mao Wang

Inventor： Bojan VRCELJ ,  Ashok Mantravadi ,  Fuyun Ling ,  Krishna Kiran Mukkavilli ,  Raghuraman Krishnamoorthi ,  Michael Mao Wang

IPC: H04W56/00 ,  H04W40/00

CPC classification number: H04L27/2613 ,  H04L5/0023 ,  H04L5/0048 ,  H04L25/0204 ,  H04L25/0216 ,  H04L25/0226 ,  H04L25/03866 ,  H04L27/2662 ,  H04L27/2675

Abstract: Systems and methods are provided for channel estimation and timing synchronization in a wireless network. In an embodiment, a method is provided for time synchronization at a wireless receiver. The method includes decoding at least one TDM pilot symbol located at a transition between wide and local waveforms and processing the TDM pilot symbol to perform time synchronization for a wireless receiver. Methods for channel estimation at a wireless receiver are also provided. This includes decoding at least one TDM pilot symbol and receiving the TDM pilot symbol from an OFDM broadcast to facilitate channel estimation for a wireless receiver.

Abstract translation: 提供了系统和方法用于无线网络中的信道估计和定时同步。 在一个实施例中，提供了一种用于在无线接收机处进行时间同步的方法。 该方法包括解码位于宽和局部波形之间的转变处的至少一个TDM导频符号，并处理TDM导频符号以对无线接收机执行时间同步。 还提供了在无线接收机处进行信道估计的方法。 这包括解码至少一个TDM导频符号并从OFDM广播接收TDM导频符号以便于无线接收机的信道估计。

公开(公告)号：US07848463B2

公开(公告)日：2010-12-07

申请号：US11248976

申请日：2005-10-11

Applicant: Linbo Li ,  Ashok Mantravadi ,  Fuyun Ling ,  Krishna Kiran Mukkavilli

Inventor： Linbo Li ,  Ashok Mantravadi ,  Fuyun Ling ,  Krishna Kiran Mukkavilli

IPC: H04L27/06

CPC classification number: H04L25/0232 ,  H04L25/022

Abstract: Time filtering channel estimates in a wireless communication system, such as an Orthogonal Frequency Division Multiplex (OFDM) system, can be used to improve the quality of channel estimates. The characteristics of an optimal channel estimate time filter can depend on the manner in which the channel estimate is determined as well as the time correlation of channel estimates. A receiver can implement an adaptive time filter for channel estimates in which the time filter response can vary based on channel estimate parameters. The channel estimate parameters can include the manner of determining channel estimates, a time correlation of channel estimates, and an estimated Doppler frequency. The time filter response can be varied continuously over a range of responses or can be varied discretely over a predetermined number of time filter responses.

Abstract translation: 在诸如正交频分复用（OFDM）系统的无线通信系统中的时间滤波信道估计可以用于提高信道估计的质量。 最优信道估计时间滤波器的特征可以取决于信道估计的方式以及信道估计的时间相关性。 接收机可以实现用于信道估计的自适应时间滤波器，其中时间滤波器响应可以基于信道估计参数而变化。 信道估计参数可以包括确定信道估计的方式，信道估计的时间相关性和估计的多普勒频率。 时间滤波器响应可以在响应范围内连续变化，或者可以在预定数量的时间滤波器响应上离散变化。