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.

公开(公告)号：US20050277429A1

公开(公告)日：2005-12-15

申请号：US10865616

申请日：2004-06-10

申请人： Rajiv Laroia ,  Junyi Li ,  Sundeep Rangan ,  Prashanth Hande

发明人： Rajiv Laroia ,  Junyi Li ,  Sundeep Rangan ,  Prashanth Hande

IPC分类号： H04W68/00 ,  H04W68/02 ,  H04Q7/20

CPC分类号： H04W68/025 ,  Y02D70/00

摘要： Methods and apparatus for efficient two-stage paging wireless communications systems are described. Wireless terminals are assigned to paging groups. A few first paging message information bits are modulated (using non-coherent modulation) into a first paging signal and communicated from a base station to wireless terminals. WTs wake-up, receive the first paging signal and quickly ascertain whether its paging group should expect a second paging signal, if so, the WT is operated to receive the second paging signal; otherwise, the WT goes back to sleep conserving power. The base station modulates (using coherent modulation) a number of second message information bits into a second paging signal and transmits the signal to WTs. From the information in first and second paging signals, a WT can determine that it is the paged WT and process the paging instructions. The intended paged WT can transmit an acknowledgement signal on a dedicated uplink resource.

摘要翻译： 描述了用于有效的两阶段寻呼无线通信系统的方法和装置。 无线终端被分配给寻呼组。 几个第一寻呼消息信息比特被调制（使用非相干调制）到第一寻呼信号中并从基站传送到无线终端。 WT唤醒，接收第一个寻呼信号，并快速确定其寻呼组是否应该预期第二个寻呼信号，如果是，则操作WT接收第二寻呼信号; 否则，WT回去睡眠节省电力。 基站将多个第二消息信息比特（使用相干调制）调制成第二寻呼信号，并将该信号发送给WT。 根据第一和第二寻呼信号中的信息，WT可以确定它是寻呼WT并处理寻呼指令。 预期的寻呼WT可以在专用上行链路资源上发送确认信号。

公开(公告)号：US08451961B2

公开(公告)日：2013-05-28

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： H03D1/04 ,  H03D1/06 ,  H03K5/01 ,  H03K6/04 ,  H04B1/10 ,  H04L1/00 ,  H04L25/08 ,  H04L27/26

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。

公开(公告)号：US07711377B2

公开(公告)日：2010-05-04

申请号：US10865616

申请日：2004-06-10

申请人： Rajiv Laroia ,  Junyi Li ,  Sundeep Rangan ,  Prashanth Hande

发明人： Rajiv Laroia ,  Junyi Li ,  Sundeep Rangan ,  Prashanth Hande

IPC分类号： H04Q7/20

CPC分类号： H04W68/025 ,  Y02D70/00

摘要： Methods and apparatus for efficient two-stage paging wireless communications systems are described. Wireless terminals are assigned to paging groups. A few first paging message information bits are modulated (using non-coherent modulation) into a first paging signal and communicated from a base station to wireless terminals. WTs wake-up, receive the first paging signal and quickly ascertain whether its paging group should expect a second paging signal, if so, the WT is operated to receive the second paging signal; otherwise, the WT goes back to sleep conserving power. The base station modulates (using coherent modulation) a number of second message information bits into a second paging signal and transmits the signal to WTs. From the information in first and second paging signals, a WT can determine that it is the paged WT and process the paging instructions. The intended paged WT can transmit an acknowledgement signal on a dedicated uplink resource.

摘要翻译： 描述了用于有效的两阶段寻呼无线通信系统的方法和装置。 无线终端被分配给寻呼组。 几个第一寻呼消息信息比特被调制（使用非相干调制）到第一寻呼信号中并从基站传送到无线终端。 WT唤醒，接收第一个寻呼信号，并快速确定其寻呼组是否应该预期第二个寻呼信号，如果是，则操作WT接收第二寻呼信号; 否则，WT回去睡眠节省电力。 基站将多个第二消息信息比特（使用相干调制）调制成第二寻呼信号，并将该信号发送给WT。 根据第一和第二寻呼信号中的信息，WT可以确定它是寻呼WT并处理寻呼指令。 预期的寻呼WT可以在专用上行链路资源上发送确认信号。

公开(公告)号：US07420939B2

公开(公告)日：2008-09-02

申请号：US10641308

申请日：2003-08-13

申请人： Rajiv Laroia ,  Junyi Li ,  John L. Fan ,  Sundeep Rangan ,  Prashanth Hande

发明人： Rajiv Laroia ,  Junyi Li ,  John L. Fan ,  Sundeep Rangan ,  Prashanth Hande

IPC分类号： H04B7/185

CPC分类号： H04W52/08 ,  H04L27/2608 ,  H04L27/362 ,  H04W52/56 ,  H04W52/60

摘要： The present invention involves apparatus and methods to perform wireless terminal transmission power control. The invention uses novel and highly efficient methods to: convey power control information, specify power control level adjustments, recognize power control information, limit interference in the power control signaling, and recognize corrupted power control signaling, thus conserving wireless terminal energy and minimizing power control signaling and associated bandwidth. Base stations send analog power control command signals, with a continuous range of control levels, to wireless terminals for transmission power adjustments. Power control signals include two components which can be used to convey information, e.g., power control commands, signal quality, device identity information. For zero power adjustment, the control component signal is not transmitted. For a non-zero adjustment, power control signals are sent using control ranges and limits, known to the base station and wireless terminal, with the scaling adjusted or synchronized based upon feedback information.

摘要翻译： 本发明涉及执行无线终端传输功率控制的装置和方法。 本发明使用新颖且高效的方法：传送功率控制信息，指定功率控制电平调整，识别功率控制信息，限制功率控制信令中的干扰，并识别损坏的功率控制信令，从而节省无线终端能量并最小化功率控制 信令和相关带宽。 基站向无线终端发送模拟功率控制命令信号，具有连续的控制级别，用于传输功率调整。 功率控制信号包括可用于传送信息的两个组件，例如功率控制命令，信号质量，设备身份信息。 对于零功率调整，控制分量信号不发送。 对于非零调整，功率控制信号使用基站和无线终端已知的控制范围和限制，基于反馈信息进行缩放调整或同步。

公开(公告)号：US07023928B2

公开(公告)日：2006-04-04

申请号：US09922885

申请日：2001-08-06

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： H04K1/10

CPC分类号： H04L27/2665 ,  H04L25/0234 ,  H04L27/2659 ,  H04L27/266 ,  H04L27/2663 ,  H04L27/2695

摘要： A synchronization of a pilot assisted channel estimation orthogonal frequency division multiplexing can be achieved by receiving a signal containing pilot symbols, providing an initial time and frequency synchronization to the signal, phase rotating the signal across time, transforming the signal with a fast Fourier transformation, phase rotating the signal across frequency, extracting the pilot symbols and generating a channel estimator. The phase rotating across time and the phase rotating across frequency are controlled by a phase rotation controller in accordance with the channel estimator. The initial time and frequency synchronization synchronizes the signal such that intercarrier interference effects and intersymbol interference effects are negligible. The signal may include plural carrier frequencies each having an arrival timing offset and a frequency offset. The signal may also include delay spread or Doppler spread. The phase rotation controller measures a phase different between the channel estimator at times k and k+Δk, where k is time and Δk is a symbol period and measures a phase difference between the channel estimator at frequencies n and n+Δn, where n is tone frequency and Δn is a frequency spacing between adjacent tones.

摘要翻译： 导频辅助信道估计正交频分复用的同步可以通过接收包含导频符号的信号，提供信号的初始时间和频率同步，跨越时间旋转信号，以快速傅立叶变换来变换信号， 使信号跨频率旋转，提取导频符号并产生信道估计器。 跨越时间旋转的相位和跨频率的相位旋转根据信道估计器由相位旋转控制器控制。 初始时间和频率同步使信号同步，使得载波间干扰效应和符号间干扰效应可以忽略不计。 信号可以包括多个载波频率，每个载波频率具有到达定时偏移和频率偏移。 信号还可以包括延迟扩展或多普勒扩展。 相位旋转控制器测量在时间k和k + Deltak处的信道估计器之间的相位，其中k是时间，Deltak是符号周期，并且测量频率n和n + Deltan之间的信道估计器之间的相位差，其中n是 音频和Deltan是相邻音调之间的频率间隔。

公开(公告)号：US06967936B1

公开(公告)日：2005-11-22

申请号：US09503040

申请日：2000-02-11

申请人： Rajiv Laroia ,  Junyi Li ,  Sundeep Rangan ,  Sathyadev Venkata Uppala

发明人： Rajiv Laroia ,  Junyi Li ,  Sundeep Rangan ,  Sathyadev Venkata Uppala

IPC分类号： H04J11/00 ,  H04B7/26 ,  H04L5/02 ,  H04L7/00 ,  H04L27/26 ,  H04Q7/00

CPC分类号： H04W56/0005 ,  H04J3/0682 ,  H04L5/023

摘要： Improved timing synchronization and access control techniques for use in an orthogonal frequency division multiplexed (OFDM) wireless system or other type of wireless communication system. In accordance with the invention, an uplink synchronization and access control system is provided in which mobile stations transmit certain timing and access signals in dedicated intervals in an uplink stream. Access control is illustratively implemented as a two-stage process in which a given mobile first transmits a generic uplink access signal in one of the intervals. If this access is accepted, the base station transmits an access acknowledgment containing initial timing and power corrections, along with initial channel assignments on which the mobile can initiate a call set-up process. For re-synchronization, mobiles transmit timing synchronization signals in the dedicated timing and access intervals. The base station measures the arrival time of the signals, and sends back appropriate timing corrections. The invention thereby ensures that orthogonality between mobiles is maintained.

摘要翻译： 用于正交频分复用（OFDM）无线系统或其他类型的无线通信系统中的改进的定时同步和接入控制技术。 根据本发明，提供一种上行链路同步和接入控制系统，其中移动台在上行链路流中以专用间隔发送某些定时和接入信号。 访问控制被示意性地实现为两阶段过程，其中给定移动单元首先在其中一个间隔中发送通用上行链路接入信号。 如果该接入被接受，则基站发送包含初始定时和功率校正的接入确认以及移动台可以在其上启动呼叫建立过程的初始信道分配。 为了重新同步，移动台以专用定时和接入间隔发送定时同步信号。 基站测量信号的到达时间，并发回适当的时序校正。 因此，本发明确保了移动台之间的正交性得以维持。

公开(公告)号：US06961364B1

公开(公告)日：2005-11-01

申请号：US09551078

申请日：2000-04-18

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： H04J11/00 ,  H04B1/7143 ,  H04B1/7156 ,  H04B7/26 ,  H04L5/02 ,  H04L27/26 ,  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。

公开(公告)号：US06920192B1

公开(公告)日：2005-07-19

申请号：US09631805

申请日：2000-08-03

申请人： Rajiv Laroia ,  Sundeep Rangan

发明人： Rajiv Laroia ,  Sundeep Rangan

IPC分类号： H01Q3/26 ,  H04B7/08 ,  H04B7/26 ,  H04L1/06

CPC分类号： H04B7/0854

摘要： Adaptive antenna array techniques for use in an orthogonal frequency division multiplexed spread-spectrum multi-access (OFDM-SSMA) cellular wireless system or other type of wireless communication system. A base station of the system includes an antenna array and a base station receiver. The base station receiver implements an adaptive antenna gain algorithm which estimates a spatial covariance matrix for each of K mobile stations communicating with the base station. The spatial covariance matrix for a given one of the mobile stations is determined at least in part based on a unique hopping sequence of the mobile station, and provides a correlation between signals received from the mobile station at different antenna elements within the antenna array. An average spatial covariance matrix for a set of received signals is also generated. The individual spatial covariance matrices and the average spatial covariance matrix are processed to generate an estimate of an interference matrix for the K mobile stations, and the estimate of the interference matrix is further processed to generate array responses for each of the mobile stations. The array response for a given mobile station is processed to determine an antenna weighting which is applied to a signal received from the given mobile station in order to facilitate detection of a corresponding transmitted symbol.

摘要翻译： 用于正交频分复用扩频多址（OFDM-SSMA）蜂窝无线系统或其他类型无线通信系统的自适应天线阵列技术。 系统的基站包括天线阵列和基站接收机。 基站接收机实现自适应天线增益算法，其估计与基站通信的K个移动站中的每一个的空间协方差矩阵。 至少部分地基于移动台的唯一跳频序列来确定给定一个移动站的空间协方差矩阵，并且提供在天线阵列内的不同天线元件处从移动站接收的信号之间的相关性。 还产生一组接收信号的平均空间协方差矩阵。 处理单个空间协方差矩阵和平均空间协方差矩阵以产生K个移动站的干扰矩阵的估计，并且对干扰矩阵的估计被进一步处理以产生每个移动站的阵列响应。 处理给定移动站的阵列响应被处理以确定施加到从给定移动台接收的信号的天线加权，以便于检测相应的发送符号。

公开(公告)号：US20050085197A1

公开(公告)日：2005-04-21

申请号：US10964885

申请日：2004-10-14

申请人： Rajiv Laroia ,  Junyi Li ,  Sundeep Rangan ,  Murari Srinivasan ,  Frank Lane ,  Prashanth Hande

发明人： Rajiv Laroia ,  Junyi Li ,  Sundeep Rangan ,  Murari Srinivasan ,  Frank Lane ,  Prashanth Hande

IPC分类号： H04B7/005 ,  H04B7/06 ,  H04B7/08 ,  H04L1/00 ,  H04W52/42 ,  H04B1/02 ,  H03C7/02 ,  H04B7/02 ,  H04B7/10 ,  H04L1/02

CPC分类号： H04B7/0604 ,  H01Q3/24 ,  H01Q3/2605 ,  H04B7/061 ,  H04B7/0691 ,  H04B7/0805 ,  H04L1/0026 ,  H04L5/0007 ,  H04L5/0023 ,  H04L5/0026 ,  H04L5/006 ,  H04W52/42

摘要： Transmit and/or receive diversity is achieved using multiple antennas. In some embodiments, a single transmitter chain within a wireless terminal is coupled over time to a plurality of transmit antennas. At any given time, a controllable switching module couples the single transmitter chain to one the plurality of transmit antennas. Over time, the switching module couples the output signals from the single transmitter chain to different transmit antennas. Switching decisions are based upon predetermined information, dwell information, and/or channel condition feedback information. Switching is performed on some dwell and/or channel estimation boundaries. In some OFDM embodiments, each of multiple transmitter chains is coupled respectively to a different transmit antenna. Information to be transmitted is mapped to a plurality of tones. Different subsets of tones are formed for and transmitted through different transmit chain/antenna sets simultaneously. The balance of tones allocated to the subsets for each antenna are changed as a function of predetermined information, dwell information, and/or channel condition feedback information.

摘要翻译： 使用多个天线实现发射和/或接收分集。 在一些实施例中，无线终端内的单个发射机链随时间耦合到多个发射天线。 在任何给定时间，可控开关模块将单个发射机链耦合到多个发射天线中的一个。 随着时间的推移，开关模块将来自单个发射机链的输出信号耦合到不同的发射天线。 切换决定基于预定信息，停留信息和/或信道条件反馈信息。 在一些驻留和/或信道估计边界上执行切换。 在一些OFDM实施例中，多个发射机链中的每一个分别耦合到不同的发射天线。 要发送的信息被映射到多个音调。 为不同的发射链/天线组同时形成和发送不同的音调子集。 分配给每个天线的子集的音调的平衡作为预定信息，停留信息和/或信道条件反馈信息的函数而改变。