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41. 发明授权

US07397838B2 Base station identification in orthogonal frequency division multiplexing based spread spectrum multiple access systems 失效
标题翻译：基于正交频分复用的扩频多址系统中的基站识别
公开(公告)号：US07397838B2
公开(公告)日：2008-07-08
申请号：US11168210
申请日：2005-06-27
申请人： Rajiv Laroia , Junyi Li , Sundeep Rangan , Pramod Viswanath
发明人： Rajiv Laroia , Junyi Li , Sundeep Rangan , Pramod Viswanath
IPC分类号： H04B1/713
CPC分类号： H04B1/7143 , H04B1/7156 , H04B2001/71563 , H04L5/0019 , H04L5/0048 , H04L25/0226 , H04L27/2613 , H04L27/2657 , H04L27/2675
摘要： A base station having the strongest downlink signal is identified by utilizing a unique slope of a pilot tone hopping sequence being transmitted by a base station. Specifically, base station identification is realized by determining the slope of the strongest received pilot signal, i.e., the received pilot signal having the maximum energy. In an embodiment of the invention, the pilot tone hopping sequence is based on a Latin Squares sequence. With a Latin Squares based pilot tone hopping sequence, all a mobile user unit needs is to locate the frequency of the pilot tones at one time because the pilot tone locations at subsequent times can be determined from the slope of the Latin Squares pilot tone hopping sequence. The slope and initial frequency shift of the pilot tone hopping sequence with the strongest received power is determined by employing a unique maximum energy detector.
摘要翻译：通过利用由基站发送的导频音跳频序列的唯一斜率，来识别具有最强下行链路信号的基站。具体地，通过确定最强接收导频信号的斜率，即具有最大能量的接收导频信号来实现基站识别。在本发明的实施例中，导频音跳频序列基于拉丁方阵序列。利用基于拉丁方阵的导频音跳频序列，移动用户单元需要的是一次定位导频音频的频率，因为可以从拉丁方正导频音跳频序列的斜率确定随后时间的导频音位置。具有最强接收功率的导频音跳频序列的斜率和初始频移通过采用独特的最大能量检测器来确定。

42. 发明申请

US20060104257A1 Method and apparatus for time and frequency synchronization of OFDM communication systems 失效
公开(公告)号：US20060104257A1
公开(公告)日：2006-05-18
申请号：US11322538
申请日：2005-12-30
申请人： Rajiv Laroia , Junyi Li , Sundeep Rangan , Hemanth Sampath
发明人： Rajiv Laroia , Junyi Li , Sundeep Rangan , Hemanth Sampath
IPC分类号： H04J3/06
CPC分类号： H04L27/2663 , H04L27/2659 , H04L27/266 , H04L27/2665 , H04L27/2675
摘要： A method and apparatus for joint time and frequency synchronization for orthogonal frequency division multiplexing (OFDM) systems. A multitone pilot signal is sent in a designated OFDM symbol period. The receiver synchronizes to the pilot signal in a two-stage procedure. The first stage estimates the frequency offset coarsely with a frequency-domain correlation method and estimates the time offset with smoothed time-domain correlation. In a multipath channel, the smoothed time offset estimate is used to locate a cyclic prefix interval which captures the maximum total signal energy. The second stage improves the frequency estimate with a computationally efficient numerical optimization method.

43. 发明授权

US06553019B1 Communications system employing orthogonal frequency division multiplexing based spread sprectrum multiple access 有权
公开(公告)号：US06553019B1
公开(公告)日：2003-04-22
申请号：US09472074
申请日：1999-12-23
申请人： Rajiv Laroia , Junyi Li , Sathyadev Venkata Uppala , Sundeep Rangan
发明人： Rajiv Laroia , Junyi Li , Sathyadev Venkata Uppala , Sundeep Rangan
IPC分类号： H04J100
CPC分类号： H04L5/026 , H04B1/7136 , H04B1/7143 , H04L5/0007
摘要： Tone sequences in a frequency hopping arrangement are generated and assigned by advantageously employing a combination of a sequence generator and a sequence assignor to generate sequences and assign them on a time slot by time slot basis. In a transmitter, the sequence generator and sequence assignor, in combination with a user tone assignor are employed to generate and assign tone sequences to a user on a time slot by time slot basis. In a receiver, the sequence generator and sequence assignor, in combination with a user tone identifier are employed to generate sequences and to identify incoming tone sequences to a user on a time slot by time slot basis. Specifically, the sequence assignment in a time slot is such that a prescribed plurality of sequences is assigned to a particular user. This partitioning of the tasks facilitates the use of a sequence generator that generates sequences with the desirable properties of interference and frequency diversity and, which, leaves the task of properly assigning these sequences among one or more users to the sequence assignor. The sequence assignor functions in such a manner that the interference and frequency diversity properties for the one or more users are preserved, and this is further facilitated by assigning sequences in such a manner that they maximally overlap prior assigned sequences. In one embodiment of the invention, a Latin square based sequence is generated in accordance with a first prescribed process. In a second embodiment of the invention, a Latin cube based sequence is generated in accordance with a second prescribed process. In a third embodiment of the invention, a Latin hypercube of prescribed dimension based sequence is generated in accordance with a third prescribed process. In still another embodiment of the invention, the principles of the invention are employed to realize frequency band hopping.

44. 发明授权

US09661519B2 Efficient reporting of information in a wireless communication system 有权
公开(公告)号：US09661519B2
公开(公告)日：2017-05-23
申请号：US11486601
申请日：2006-07-14
申请人： Arnab Das , Sundeep Rangan , Pablo Anigstein , Junyi Li , Sathyadev Venkata Uppala , Rajiv Laroia
发明人： Arnab Das , Sundeep Rangan , Pablo Anigstein , Junyi Li , Sathyadev Venkata Uppala , Rajiv Laroia
IPC分类号： H04W24/10 , H04L1/00 , H04W24/00
CPC分类号： H04W24/10 , H04L1/0006 , H04L1/0026 , H04W24/00
摘要： Techniques for efficiently sending reports in a wireless communication system are described. Reports may be sent repetitively in accordance with a reporting format. A terminal receives an assignment of a control channel used to send reports and determines a reporting format to use based on the assignment. The reporting format indicates a specific sequence of reports sent in specific locations of a control channel frame. The terminal generates a set of reports for each reporting interval and arranges the set of reports in accordance with the reporting format. The terminal repetitively sends a plurality of sets of reports in a plurality of reporting intervals. Reports may also be sent adaptively based on operating conditions. An appropriate reporting format may be selected based on the operating conditions of the terminal, which may be characterized by environment (e.g., mobility), capabilities, QoS, and/or other factors.

45. 发明申请

US20100211540A9 Efficient reporting of information in a wireless communication system 有权
标题翻译：在无线通信系统中有效地报告信息
公开(公告)号：US20100211540A9
公开(公告)日：2010-08-19
申请号：US11486601
申请日：2006-07-14
申请人： Arnab Das , Sundeep Rangan , Pablo Anigstein , Junyi Li , Sathyadev Venkata Uppala , Rajiv Laroia
发明人： Arnab Das , Sundeep Rangan , Pablo Anigstein , Junyi Li , Sathyadev Venkata Uppala , Rajiv Laroia
IPC分类号： G06F17/30
CPC分类号： H04W24/10 , H04L1/0006 , H04L1/0026 , H04W24/00
摘要： Techniques for efficiently sending reports in a wireless communication system are described. Reports may be sent repetitively in accordance with a reporting format. A terminal receives an assignment of a control channel used to send reports and determines a reporting format to use based on the assignment. The reporting format indicates a specific sequence of reports sent in specific locations of a control channel frame. The terminal generates a set of reports for each reporting interval and arranges the set of reports in accordance with the reporting format. The terminal repetitively sends a plurality of sets of reports in a plurality of reporting intervals. Reports may also be sent adaptively based on operating conditions. An appropriate reporting format may be selected based on the operating conditions of the terminal, which may be characterized by environment (e.g., mobility), capabilities, QoS, and/or other factors.
摘要翻译：描述在无线通信系统中有效地发送报告的技术。可以按照报告格式重复发送报告。终端接收用于发送报告的控制信道的分配，并根据分配确定要使用的报告格式。报告格式指示在控制信道帧的特定位置发送的特定报告序列。终端为每个报告间隔生成一组报告，并根据报告格式安排报告集。终端在多个报告间隔重复发送多组报告。报告也可以根据操作条件自适应地发送。可以基于可以由环境（例如，移动性），能力，QoS和/或其他因素来表征的终端的操作条件来选择适当的报告格式。

46. 发明授权

US07630339B2 Methods and apparatus of providing transmit diversity in a multiple access wireless communication system 有权
标题翻译：在多址无线通信系统中提供发射分集的方法和装置
公开(公告)号：US07630339B2
公开(公告)日：2009-12-08
申请号：US10763944
申请日：2004-01-23
申请人： Rajiv Laroia , Junyi Li , Sundeep Rangan , Murari Srinivasan
发明人： Rajiv Laroia , Junyi Li , Sundeep Rangan , Murari Srinivasan
IPC分类号： H04Q7/00
CPC分类号： H04B7/0626
摘要： Methods and apparatus for providing channel diversity to wireless terminals (WTs) in a manner that reduces the latency between the time a WT encounters satisfactory channel conditions are described. A plurality of communications channels with different physical characteristics are maintained in a cell by a base station (BS). Each WT monitors multiple channels and maintains multiple channel estimates at the same time so that rapid switching between channels is possible. Channel quality information is conveyed from each WT to the BS. The WT or BS selects a channel based on the measured channel quality. By supporting multiple channels and by introducing periodic variations into the channels in various embodiments, the time before a WT encounters a channel with good or acceptable channel conditions is minimized even if the WT does not change location. Multiple antennas are used at the BS to support numerous channels simultaneously, e.g., by controlling antenna patterns.
摘要翻译：描述了以降低WT遇到令人满意的信道条件的时间之间的等待时间的方式向无线终端（WT）提供信道分集的方法和装置。具有不同物理特性的多个通信信道由基站（BS）保持在小区中。每个WT监视多个信道并同时维持多个信道估计，使得信道之间的快速切换是可能的。信道质量信息从每个WT传送到BS。 WT或BS基于测量的信道质量来选择信道。通过支持多个信道并且在各种实施例中引入周期性变化到信道中，即使WT不改变位置，WT遇到具有良好或可接受的信道条件的信道之前的时间被最小化。在BS处使用多个天线来同时支持多个信道，例如通过控制天线方向图。

47. 发明授权

US07558245B2 Method and apparatus for time and frequency synchronization of OFDM communication systems 失效
公开(公告)号：US07558245B2
公开(公告)日：2009-07-07
申请号：US11322538
申请日：2005-12-30
申请人： Rajiv Laroia , Junyi Li , Sundeep Rangan , Hemanth T. Sampath
发明人： Rajiv Laroia , Junyi Li , Sundeep Rangan , Hemanth T. Sampath
IPC分类号： H04J3/06
CPC分类号： H04L27/2663 , H04L27/2659 , H04L27/266 , H04L27/2665 , H04L27/2675
摘要： A method and apparatus for joint time and frequency synchronization for orthogonal frequency division multiplexing (OFDM) systems. A multitone pilot signal is sent in a designated OFDM symbol period. The receiver synchronizes to the pilot signal in a two-stage procedure. The first stage estimates the frequency offset coarsely with a frequency-domain correlation method and estimates the time offset with smoothed time-domain correlation. In a multipath channel, the smoothed time offset estimate is used to locate a cyclic prefix interval which captures the maximum total signal energy. The second stage improves the frequency estimate with a computationally efficient numerical optimization method.

48. 发明申请

US20090129488A1 METHOD OF REDUCING INTERFERENCE 失效
标题翻译：减少干扰的方法
公开(公告)号：US20090129488A1
公开(公告)日：2009-05-21
申请号：US11944197
申请日：2007-11-21
申请人： Rajiv Laroia , Sundeep Rangan , Junyi Li , Thomas Richardson , Saurabh Tavildar
发明人： Rajiv Laroia , Sundeep Rangan , Junyi Li , Thomas Richardson , Saurabh Tavildar
IPC分类号： H04B1/10 , H04L27/28
CPC分类号： H04L27/2647 , H04B1/7103 , H04B7/0854 , H04B7/0857 , H04B2201/70702
摘要： Various schemes for reducing effects of interference within communication systems are disclosed. A transmitter transmits a signal in a first time interval and a scrambled version of the signal in a second time interval, which does not overlap with the first time interval. A receiver receives a composite signal including a signal transmitted from the desired transmitter as well as signals from interferers in the first or the second time interval. The receiver determines a dominant interferer and obtains knowledge of signal scrambling done by the interferer as well as the desired transmitter by sensing an identification associated with the interferer or the desired transmitter. This knowledge is employed to determine coefficients for combining the received composite signals received in the first and the second time interval in order to recover the desired signal in a manner that maximizes the SNR associated with the desired signal or completely cancels the dominant interference.
摘要翻译：公开了用于减少通信系统内的干扰影响的各种方案。发射机以与第一时间间隔不重叠的第二时间间隔发送第一时间间隔中的信号和信号的加扰版本。接收机在第一或第二时间间隔中接收包括从所需发射机发送的信号以及来自干扰源的信号的复合信号。接收机确定主要干扰源，并且通过感测与干扰源或期望发射机相关联的标识来获得由干扰源以及所需发射机完成的信号加扰的知识。该知识用于确定用于组合在第一和第二时间间隔中接收的接收的复合信号的系数，以便以最大化与期望信号相关联的SNR或完全抵消显性干扰的方式恢复期望信号。

49. 发明授权

US07027429B2 Method and apparatus for time and frequency synchronization of OFDM communication systems 失效
公开(公告)号：US07027429B2
公开(公告)日：2006-04-11
申请号：US09884581
申请日：2001-06-19
申请人： Rajiv Laroia , Junyi Li , Sundeep Rangan , Hemanth T. Sampath
发明人： Rajiv Laroia , Junyi Li , Sundeep Rangan , Hemanth T. Sampath
IPC分类号： H04J3/06
CPC分类号： H04L27/2663 , H04L27/2659 , H04L27/266 , H04L27/2665 , H04L27/2675
摘要： A method and apparatus for joint time and frequency synchronization for orthogonal frequency division multiplexing (OFDM) systems. A multitone pilot signal is sent in a designated OFDM symbol period. The receiver synchronizes to the pilot signal in a two-stage procedure. The first stage estimates the frequency offset coarsely with a frequency-domain correlation method and estimates the time offset with smoothed time-domain correlation. In a multipath channel, the smoothed time offset estimate is used to locate a cyclic prefix interval which captures the maximum total signal energy. The second stage improves the frequency estimate with a computationally efficient numerical optimization method.

50. 发明授权

US08774846B2 Methods and apparatus relating to wireless terminal beacon signal generation, transmission, and/or use 有权
标题翻译：与无线终端信标信号生成，传输和/或使用有关的方法和装置
公开(公告)号：US08774846B2
公开(公告)日：2014-07-08
申请号：US11621955
申请日：2007-01-10
申请人： Rajiv Laroia , Sundeep Rangan , Arnab Das , Frank A. Lane , Junyi Li
发明人： Rajiv Laroia , Sundeep Rangan , Arnab Das , Frank A. Lane , Junyi Li
IPC分类号： H04B7/00 , H04W36/00
CPC分类号： H04W40/244 , H04J3/0602 , H04L5/0016 , H04L5/0035 , H04L5/0048 , H04L27/2601 , H04L27/261 , H04W8/005 , H04W16/14 , H04W28/04 , H04W28/18 , H04W36/16 , H04W36/24 , H04W40/24 , H04W48/08 , H04W48/16 , H04W48/20 , H04W52/0229 , H04W52/04 , H04W72/02 , H04W76/14 , H04W84/042 , H04W84/18 , H04W88/02 , H04W88/04 , H04W88/06 , H04W88/10 , Y02D70/1222 , Y02D70/1224 , Y02D70/1242 , Y02D70/1262 , Y02D70/142 , Y02D70/144 , Y02D70/146 , Y02D70/162 , Y02D70/164 , Y02D70/168 , Y02D70/22 , Y02D70/23
摘要： A portable wireless terminal generates and transmits a beacon signal. The beacon signal includes a sequence of beacon signal bursts, each beacon signal burst including one or more beacon symbols. A beacon symbol is transmitted using the air link resources of a beacon symbol transmission unit at a relatively high transmission power level with respect to user data symbols transmitted from the same wireless terminal, thus facilitating easy detection by other wireless terminals. The beacon symbols of the beacon signal occupy a small fraction of the total available air link resources. Beacon signals can, and sometimes do, convey wireless terminal identification information, via the location of the beacon symbols within the portion of the air link resource reserved for beacon symbol transmission units.
摘要翻译：便携式无线终端生成并发送信标信号。信标信号包括信标信号脉冲序列，每个信标信号脉冲串包括一个或多个信标符号。相对于从同一无线终端发送的用户数据符号，以相对高的发送功率电平的信标符号发送单元的空中链路资源发送信标符号，便于其他无线终端的容易检测。信标信号的信标符号占据总可用空中链路资源的一小部分。信标信号可以并且有时可以通过为为信标符号传输单元预留的空中链路资源的部分内的信标符号的位置传送无线终端识别信息。

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