Methods and apparatus for use in obtaining frequency synchronization in an OFDM communication system
    1.
    发明授权
    Methods and apparatus for use in obtaining frequency synchronization in an OFDM communication system 失效
    用于在OFDM通信系统中获得频率同步的方法和装置

    公开(公告)号:US06700866B1

    公开(公告)日:2004-03-02

    申请号:US09594890

    申请日:2000-06-14

    IPC分类号: H04B700

    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。

    Methods and apparatus for use in obtaining frame synchronization in an OFDM communication system
    2.
    发明授权
    Methods and apparatus for use in obtaining frame synchronization in an OFDM communication system 有权
    用于在OFDM通信系统中获得帧同步的方法和装置

    公开(公告)号:US06807147B1

    公开(公告)日:2004-10-19

    申请号:US09592961

    申请日:2000-06-13

    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。

    Methods and apparatus for use in obtaining frequency synchronization in an OFDM communication system
    3.
    发明授权
    Methods and apparatus for use in obtaining frequency synchronization in an OFDM communication system 有权
    用于在OFDM通信系统中获得频率同步的方法和装置

    公开(公告)号:US06768714B1

    公开(公告)日:2004-07-27

    申请号:US09594886

    申请日:2000-06-14

    IPC分类号: H04J1100

    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.

    Method for linearization of RF transmission electronics using baseband
pre-distortion in T/R compensation pilot signals
    5.
    发明授权
    Method for linearization of RF transmission electronics using baseband pre-distortion in T/R compensation pilot signals 失效
    在T / R补偿导频信号中使用基带预失真的RF传输电子线路化的方法

    公开(公告)号:US5872814A

    公开(公告)日:1999-02-16

    申请号:US804615

    申请日:1997-02-24

    CPC分类号: H03F1/3241

    摘要: An RF communications technique pre-distorts the signal in the baseband prior to its being applied to the RF transmitter, to avoid producing harmonics when the resultant signal is processed by the RF transmitter. Pilot tones are used to test the channels between the base station and a remote station. The technique provides an improved way to minimize the harmonic distortion imposed by RF transmitters.

    摘要翻译: RF通信技术在被施加到RF发射机之前预先对基带中的信号进行预失真,以避免当由RF发射机处理所得到的信号时产生谐波。 导频音调用于测试基站和远程站之间的信道。 该技术提供了一种改进的方法来最小化由RF发射器施加的谐波失真。