公开(公告)号：US07065165B2

公开(公告)日：2006-06-20

申请号：US10414576

申请日：2003-04-14

申请人： Jari M. Heinonen ,  Michael R. Hirano ,  Hongliang Zhang

发明人： Jari M. Heinonen ,  Michael R. Hirano ,  Hongliang Zhang

IPC分类号： H04L27/08

CPC分类号： H04L27/2647 ,  H03G3/001 ,  H03G3/3089

摘要： Automatic gain control (AGC) methods and apparatus suitable for use in orthogonal frequency division multiplexing (OFDM) receivers are described. One AGC method includes the steps of repeatedly performing a first AGC process which adjusts amplifier gain based on determining that a signal level of multiple time sample values is outside a limit set by a first predefined threshold; and repeatedly performing a second AGC process which adjusts the amplifier gain based on determining that a signal level of multiple frequency sample values associated with a plurality of pilot tones is outside a limit set by a second predefined threshold. Preferably, the first AGC process is performed repeatedly at a first rate and the second AGC process is performed repeatedly at a second rate that is less than the first rate.

公开(公告)号：US06389087B1

公开(公告)日：2002-05-14

申请号：US09593449

申请日：2000-06-14

申请人： Jari M. Heinonen ,  Michael R. Hirano

发明人： Jari M. Heinonen ,  Michael R. Hirano

IPC分类号： H04L700

CPC分类号： H04L27/2657 ,  H04L27/2662 ,  H04L27/2675 ,  H04L27/2678

摘要： A method, apparatus and system detects a loss of synchronization between a transmitter and a receiver in a multiple-carrier communication system such as an OFDM system. A guard band synchronization detector provides a synchronization indicator based on the energy detected within a guard band where a pilot tone is transmitted adjacent to the guard band. A timing error results in energy leakage into one or more guard bands. In one embodiment, a plurality of synchronization indicators are observed to determine whether a loss of synchronization between a transmitter and a receiver in the wireless system has occurred.

摘要翻译： 方法，装置和系统检测诸如OFDM系统的多载波通信系统中的发射机和接收机之间的同步丢失。 保护频带同步检测器基于在与保护频带相邻发送导频音的保护频带内检测到的能量提供同步指示符。 定时误差导致能量泄漏到一个或多个保护带。 在一个实施例中，观察到多个同步指示符，以确定是否发生了无线系统中的发射机和接收机之间的同步丢失。

公开(公告)号：US06363127B1

公开(公告)日：2002-03-26

申请号：US09591043

申请日：2000-06-09

申请人： Jari M. Heinonen ,  Michael R. Hirano ,  Hongliang Zhang

发明人： Jari M. Heinonen ,  Michael R. Hirano ,  Hongliang Zhang

IPC分类号： H04L2708

CPC分类号： H04L27/2647 ,  H03G3/001 ,  H03G3/3089

摘要： Automatic gain control (AGC) methods and apparatus suitable for use in orthogonal frequency division multiplexing (OFDM) receivers are described. One AGC method includes the steps of repeatedly performing a first AGC process which adjusts amplifier gain based on determining that a signal level of multiple time sample values is outside a limit set by a first predefined threshold; and repeatedly performing a second AGC process which adjusts the amplifier gain based on determining that a signal level of multiple frequency sample values associated with a plurality of pilot tones is outside a limit set by a second predefined threshold. Preferably, the first AGC process is performed repeatedly at a first rate and the second AGC process is performed repeatedly at a second rate that is less than the first rate.

摘要翻译： 描述适用于正交频分复用（OFDM）接收机的自动增益控制（AGC）方法和装置。 一种AGC方法包括以下步骤：重复执行第一AGC处理，其基于确定多个时间采样值的信号电平超出由第一预定阈值设置的限制来调节放大器增益; 以及重复执行第二AGC处理，其基于确定与多个导频音调相关联的多个频率采样值的信号电平超出由第二预定阈值设置的极限，来调整放大器增益。 优选地，以第一速率重复执行第一AGC处理，并且以小于第一速率的第二速率重复执行第二AGC处理。

公开(公告)号：US06940933B1

公开(公告)日：2005-09-06

申请号：US09593547

申请日：2000-06-14

申请人： Jari M. Heinonen ,  Michael R. Hirano

发明人： Jari M. Heinonen ,  Michael R. Hirano

IPC分类号： H04L7/00 ,  H04L27/26

CPC分类号： H04L27/2662 ,  H04L27/261 ,  H04L27/2657 ,  H04L27/2675

摘要： A method, apparatus and system detects a loss of synchronization between a transmitter and a receiver in a multiple-carrier communication system such as an OFDM system. A phase-frequency synchronization detector determines when the receiver has lost synchronization with the transmitter based on a phase-frequency relationship of plurality of pilot signals transmitted at different frequencies from the transmitter and received at the receiver. A loss of synchronization is detected when a slope of a line defined by the phase-frequency relationship exceeds a timing threshold more at a rate in excess of an occurrence threshold within a time period.

摘要翻译： 方法，装置和系统检测诸如OFDM系统的多载波通信系统中的发射机和接收机之间的同步丢失。 相位 - 频率同步检测器基于在与发射机不同的频率发送并在接收机处接收的多个导频信号的相位 - 频率关系，确定接收机何时已经失去与发射机的同步。 当由相位 - 频率关系定义的线的斜率在一段时间内以超过发生阈值的速率超过定时阈值时，检测到同步丢失。

公开(公告)号：US06930995B1

公开(公告)日：2005-08-16

申请号：US09593215

申请日：2000-06-14

申请人： Jari M. Heinonen ,  Michael R. Hirano

发明人： Jari M. Heinonen ,  Michael R. Hirano

IPC分类号： H04L27/26 ,  H04J3/06

CPC分类号： H04L27/2662 ,  H04L27/2655 ,  H04L27/2657 ,  H04L27/2675 ,  H04L27/2678

摘要： A method, apparatus and system detects a loss of synchronization between a transmitter and a receiver in a multiple-carrier communication system such as an OFDM system. A plurality of synchronization indicators are observed to determine whether a loss of synchronization between a transmitter and a receiver in the wireless system has occurred. In one embodiment, the receiver is determined to have lost synchronization with the transmitter if two or more of the three synchronization indicators indicate a loss of synchronization. In such an embodiment, the three synchronization indicators include a timing error indicator, an energy guard band indicator and a phase-frequency slope indicator.

摘要翻译： 方法，装置和系统检测诸如OFDM系统的多载波通信系统中的发射机和接收机之间的同步丢失。 观察到多个同步指示符以确定是否发生了无线系统中的发射机和接收机之间的同步丢失。 在一个实施例中，如果三个同步指示符中的两个或更多个指示同步丢失，则确定接收机与发射机失去同步。 在这样的实施例中，三个同步指示器包括定时误差指示符，能量保护带指示符和相位 - 频率斜率指示符。

公开(公告)号：US07095708B1

公开(公告)日：2006-08-22

申请号：US09594467

申请日：2000-06-14

申请人： Siavash Alamouti ,  Jeffrey Battin ,  David B. Gibbons ,  James Timothy Golden ,  Michael R. Hirano ,  Elliott Hoole ,  Mary Jesse ,  Robert Lee Maxwell ,  Steven E. McMeekin ,  David J. Nix ,  David James Ryan ,  Gregory J. Veintimilla ,  Hongliang Zhang

发明人： Siavash Alamouti ,  Jeffrey Battin ,  David B. Gibbons ,  James Timothy Golden ,  Michael R. Hirano ,  Elliott Hoole ,  Mary Jesse ,  Robert Lee Maxwell ,  Steven E. McMeekin ,  David J. Nix ,  David James Ryan ,  Gregory J. Veintimilla ,  Hongliang Zhang

IPC分类号： H04J11/00

CPC分类号： H04L27/2627 ,  H04L5/0007 ,  H04L5/0048 ,  H04L5/143 ,  H04L27/2604 ,  H04L27/34

摘要： A fixed wireless system (FWS) utilizing Orthogonal Frequency Division Multiplexing (OFDM) communication techniques is spectrally efficient and responsive to communications involving both voice and high speed data, such as Internet data. The FWS includes a wireless base unit; a plurality of fixed wireless remote units; a plurality of wireless data traffic channels available between the wireless base unit and the plurality of fixed wireless remote units; and a plurality of wireless voice traffic channels available between the wireless base unit and the plurality of fixed wireless remote units. Each wireless traffic channel is identifiable by a unique combination of frequency and time slots. Each wireless data traffic channel is used for carrying high speed data in addressed data packets to and from the plurality of fixed wireless remote units. On the other hand, each wireless voice traffic channel can be assigned and dedicated to a particular voice communication call involving one of the plurality of fixed wireless remote units for carrying voice data of the call.

摘要翻译： 使用正交频分复用（OFDM）通信技术的固定无线系统（FWS）对于涉及语音和高速数据（诸如因特网数据）的通信是有效的并且响应。 FWS包括无线基站单元; 多个固定无线遥控单元; 在无线基站单元和多个固定无线远程单元之间可用的多个无线数据业务信道; 以及在无线基站单元和多个固定无线远程单元之间可用的多个无线语音业务信道。 每个无线业务信道可以通过频率和时隙的独特组合来识别。 每个无线数据业务信道用于承载来自多个固定无线远程单元的寻址数据分组中的高速数据。 另一方面，每个无线语音业务信道可以被分配并专用于涉及用于承载该呼叫的语音数据的多个固定无线远程单元中的一个的特定语音通信呼叫。

公开(公告)号：US06700866B1

公开(公告)日：2004-03-02

申请号：US09594890

申请日：2000-06-14

申请人： Jari M. Heinonen ,  Michael R. Hirano ,  Steven E. McMeekin ,  Reijo Savola ,  William H. Warner

发明人： Jari M. Heinonen ,  Michael R. Hirano ,  Steven E. McMeekin ,  Reijo Savola ,  William H. Warner

IPC分类号： H04B700

CPC分类号： H04L27/266 ,  H04L27/2659 ,  H04L27/2675

摘要： An iterative method involves performing a coarse frequency correction process which adjusts receiver frequency so that a pilot tone signal is within a predetermined frequency range and, after performing the coarse frequency correction process, performing a fine frequency correction process which adjusts receiver frequency so that the pilot tone signal is substantially aligned with a pilot tone reference within the predetermined frequency range. By performing these processes, the receiver frequency may be adjusted so that the alias pilot tone signal is substantially aligned with the pilot tone reference and the pilot tone signal is undesirably shifted outside the predetermined frequency range. To eliminate this condition, the method further involves performing the coarse frequency correction process again and, after performing the coarse frequency correction process again, performing the fine frequency correction process again. By performing the coarse frequency correction process again, receiver frequency is adjusted so that the pilot tone signal is within both the predetermined frequency range and the Nyquist sampling frequency range. By performing the fine frequency correction process again, receiver frequency is adjusted so that the pilot tone signal is substantially aligned with the pilot tone reference.

摘要翻译： 迭代方法包括进行粗调频率校正处理，其调整接收机频率，使得导频音信号在预定频率范围内，并且在执行粗频率校正处理之后，执行调整接收机频率的精细频率校正处理， 音调信号基本上与预定频率范围内的导频音基准一致。 通过执行这些处理，可以调整接收机频率，使得别名导频音信号基本上与导频音调参考一致，并且导频音信号不期望地偏移到预定频率范围之外。 为了消除这种情况，该方法还包括再次执行粗频率校正处理，并且在再次执行粗频率校正处理之后再次执行精细频率校正处理。 通过再次执行粗频率校正处理，调整接收机频率，使得导频音信号在预定频率范围和奈奎斯特采样频率范围内。 通过再次执行精细频率校正处理，调整接收机频率，使得导频音信号基本上与导频音基准一致。

公开(公告)号：US06807147B1

公开(公告)日：2004-10-19

申请号：US09592961

申请日：2000-06-13

申请人： Jari M. Heinonen ,  Michael R. Hirano ,  Steven E. McMeekin

发明人： Jari M. Heinonen ,  Michael R. Hirano ,  Steven E. McMeekin

IPC分类号： H04J1100

CPC分类号： H04L27/2656 ,  H04L27/2675

摘要： An orthogonal frequency division multiplexing (OFDM) communication system includes base units which simultaneously transmit pilot tones in a predetermined pilot tone pattern during one or more time slots of a message slot. OFDM signals are received within a time slot; an OFDM signal level is determined at each frequency of a plurality of pilot tone frequencies; the signal levels and the predetermined pilot tone pattern are correlated; and a pattern detection value based on performing the correlation is generated and stored. This process is repeated for each time slot of a plurality of time slots. This process may be repeated for a plurality of message frame durations to produce a plurality of averaged pattern detection values, following which the plurality of averaged pattern detection values and a predetermined message frame pattern may be correlated. Then, a boundary of a message slot may be detected based on the correlation.

摘要翻译： 正交频分复用（OFDM）通信系统包括在消息时隙的一个或多个时隙期间以预定导频音模式同时发送导频音的基本单元。 在时隙内接收OFDM信号; 在多个导频音频率的每个频率处确定OFDM信号电平; 信号电平和预定导频音模式相关; 并且生成并存储基于执行相关性的图案检测值。 对于多个时隙的每个时隙重复该过程。 可以对多个消息帧持续时间重复该过程以产生多个平均模式检测值，随后可以将多个平均模式检测值和预定消息帧模式相关联。 然后，可以基于相关性来检测消息时隙的边界。

公开(公告)号：US06768714B1

公开(公告)日：2004-07-27

申请号：US09594886

申请日：2000-06-14

申请人： Jari M. Heinonen ,  Michael R. Hirano ,  Steven E. McMeekin

发明人： Jari M. Heinonen ,  Michael R. Hirano ,  Steven E. McMeekin

IPC分类号： H04J1100

CPC分类号： H04L27/2662 ,  H04L27/2659 ,  H04L27/266 ,  H04L27/2675

摘要： A frequency correction process involves the steps of generating a plurality of tone values for a plurality of tone bins, where the plurality of tone bins includes a first set of tone bins assigned to a first frequency range and a second set of tone bins assigned to a second frequency range; performing complex conjugate multiplication between the tone values of the first and the second sets of tone bins; identifying a maximum value from results of the complex conjugate multiplication; and shifting receiver frequency based on a location of the maximum value relative to a predetermined pilot tone location. In this method, the first frequency range corresponds to a lower edge portion of a frequency band of interest, an upper edge portion of a lower adjacent frequency band, and a lower guard band in between the lower and the upper edge portions; and the second frequency range corresponds to an upper edge portion of the frequency band of interest, a lower edge portion of an upper adjacent frequency band, and an upper guard band in between the upper and lower edge portions.

公开(公告)号：US06574292B2

公开(公告)日：2003-06-03

申请号：US10051714

申请日：2002-01-17

申请人： Jari M. Heinonen ,  Michael R. Hirano ,  Hongliang Zhang

发明人： Jari M. Heinonen ,  Michael R. Hirano ,  Hongliang Zhang

IPC分类号： H04L2708

CPC分类号： H04L27/2647 ,  H03G3/001 ,  H03G3/3089

摘要： Automatic gain control (AGC) methods and apparatus suitable for use in orthogonal frequency division multiplexing (OFDM) receivers are described. One AGC method includes the steps of repeatedly performing a first AGC process which adjusts amplifier gain based on determining that a signal level of multiple time sample values is outside a limit set by a first predefined threshold; and repeatedly performing a second AGC process which adjusts the amplifier gain based on determining that a signal level of multiple frequency sample values associated with a plurality of pilot tones is outside a limit set by a second predefined threshold. Preferably, the first AGC process is performed repeatedly at a first rate and the second AGC process is performed repeatedly at a second rate that is less than the first rate.