Method of transmitting orthogonal frequency division multiplex signal,
and transmitter and receiver employed therefor
    1.
    发明授权
    Method of transmitting orthogonal frequency division multiplex signal, and transmitter and receiver employed therefor 失效
    发送正交频分复用信号的方法及其发射机和接收机

    公开(公告)号:US5682376A

    公开(公告)日:1997-10-28

    申请号:US572719

    申请日:1995-12-14

    IPC分类号: H04L27/26 H04J11/00 H04L27/28

    CPC分类号: H04L27/2607 H04L27/2614

    摘要: A complex multiplier complex-multiplies a carrier modulation signal group for decoding the phases and amplitudes of a plurality of carriers which are orthogonal to each other on the frequency axis by a complex signal group having a predetermined specific pattern which varies in phase at random. An inverse Fourier transformer performs inverse Fourier transformation on an output of the complex multiplier, for transforming a digital signal which is multiplexed on the frequency axis to an OFDM signal on the time axis. A guard interval insertion part adds front and rear guard intervals to front and rear parts of each symbol of the OFDM signal respectively. The front and rear guard intervals include data which are identical to those of rear and front end parts of the corresponding symbol respectively. Arithmetic processing which is reverse to that on a transmission side is performed on a receiving side, whereby distortion of received data is removed. Thus, the OFDM signal can be transmitted with no waveform distortion on a data component of each symbol on the frequency axis after Fourier transformation even if a reflected wave is superposed on a direct wave due to a multipath.

    摘要翻译: 复数乘法器复数乘法载波调制信号组,用于解码在频率轴上彼此正交的多个载波的相位和幅度,具有随机相位变化的预定特定模式的复信号组。 傅里叶逆变换器对复数乘法器的输出执行逆傅立叶变换,用于将在频率轴上复用的数字信号在时间轴上变换为OFDM信号。 保护间隔插入部分分别向OFDM信号的每个符号的前后部分添加前后保护间隔。 前后保护间隔包括与相应符号的后端部分和前端部分相同的数据。 在接收侧执行与发送侧相反的算术处理,从而去除接收数据的失真。 因此,即使由于多径而将反射波叠加在直接波上,也可以在傅立叶变换之后的频率轴上的每个符号的数据分量上不发送波形失真的OFDM信号。

    Method of transmitting orthogonal frequency division multiplexing signal
and receiver thereof
    2.
    发明授权
    Method of transmitting orthogonal frequency division multiplexing signal and receiver thereof 失效
    发送正交频分复用信号的方法及其接收机

    公开(公告)号:US5774450A

    公开(公告)日:1998-06-30

    申请号:US580887

    申请日:1995-12-29

    IPC分类号: H04L27/26 H04J11/00 H04L27/34

    摘要: An orthogonal frequency division multiplexing signal transmitted from the transmitting end to the receiving end intermittently includes a particular symbol S0 having a predetermined particular pattern in addition to a symbol Sm including data to be transmitted. At the receiving end, the variation in the receiving level and/or the variation in the frequency band of a received signal are detected and corrected on the basis of the received particular symbol S0. Since the particular symbol S0 has a particular pattern, the variation in the level and/or the variation in the frequency are strongly correlated with the variation in the receiving level and/or the variation in the frequency band of the received signal. Consequently, the variation in the receiving level and/or the variation in the frequency band of the received signal can be accurately detected from the particular symbol S0 and consequently high-precision correction can be made.

    摘要翻译: 从发送端到接收端间歇地发送的正交频分复用信号除了包括要发送的数据的符号Sm之外还包括具有预定特定模式的特定符号S0。 在接收端,基于所接收的特定符号S0来检测和校正接收信号的接收电平的变化和/或频带的变化。 由于特定符号S0具有特定的模式,所以电平和/或频率变化的变化与接收信号的接收电平的变化和/或频带的变化密切相关。 因此,可以从特定符号S0精确地检测接收电平的接收电平的变化和/或频带的变化,从而可以进行高精度校正。

    Access control method in communication system
    3.
    发明授权
    Access control method in communication system 失效
    通信系统中的访问控制方法

    公开(公告)号:US6052377A

    公开(公告)日:2000-04-18

    申请号:US863334

    申请日:1997-05-27

    CPC分类号: H04L12/403 H04B7/2643

    摘要: A down-link frame generating/transferring portion 12 detects a free channel from among a plurality of previously assigned up-link channels. The down-link frame generating/transferring portion 12 selects a secondary station 2 to which the free channel is to be assigned by referring to an address table 11 every time it detects a free channel. Then the down-link frame generating/transferring portion 12 sends out onto a down-link channel a down-link frame in which the secondary station address of the selected secondary station is set in an address slot corresponding to the free channel.

    摘要翻译: 下行链路帧生成/发送部分12从多个先前分配的上行链路信道中检测空闲信道。 下行链路帧生成/发送部分12每当检测到空闲信道时,通过参考地址表11来选择要分配空闲信道的次站2。 然后,下行链路帧生成/发送部分12向下行链路信道发送下行链路帧,其中所选择的辅助站的次站地址被设置在与自由信道相对应的地址时隙中。

    Modulator
    4.
    发明授权
    Modulator 失效
    调制器

    公开(公告)号:US06184756B2

    公开(公告)日:2001-02-06

    申请号:US09119644

    申请日:1998-07-21

    IPC分类号: H04L2736

    CPC分类号: H04L27/00

    摘要: A low frequency signal generating portion 1 generates a first discrete signal (a signal sampled at a first sampling rate f1). A band pass portion 2 operates at a second sampling rate f2, performs a frequency selecting operation to a second discrete signal generated when the first discrete signal generated by the low frequency signal generating portion 1 is inputted, and generates a modulated signal with a prescribed center frequency.

    摘要翻译: 低频信号产生部分1产生第一离散信号(以第一采样速率f1采样的信号)。 带通部分2以第二采样率f2操作,对由低频信号产生部分1产生的第一离散信号输入时产生的第二离散信号执行频率选择操作,并产生具有规定中心的调制信号 频率。

    Method and apparatus for reproducing carrier
    5.
    发明授权
    Method and apparatus for reproducing carrier 失效
    用于再现载体的方法和装置

    公开(公告)号:US6018551A

    公开(公告)日:2000-01-25

    申请号:US904265

    申请日:1997-07-31

    摘要: A complex multiplier 5 complex-multiplies base band signals x and y obtained from a receive signal by local oscillation signals c and s, to output complex detection signals p and q. A phase difference detecting portion 7 outputs the amount of the detected phase difference corresponding to the phase difference between the phase of the receive signal and the phase of the local oscillation signals. A loop filter 8 emphasizes its DC component. A local oscillation portion 6 outputs local oscillation signals having a frequency corresponding to the amount of the detected phase difference. A region judging portion 9 judges which of regions on a complex plane is one to which the base band signals belong, and outputs a region signal. A most frequent region judging portion 10 judges which of the regions is one in which the base band signals are concentrated most frequently upon input of the region signal a predetermined number of times. An initial phase generator 11 generates an initial phase corresponding to a most frequent region. The local oscillation portion 6 sets the initial phase as an initial value of the phase of the local oscillation signals. It is first judged which of the regions previously obtained by division on the complex plane is one in which the complex base band signals are concentrated most frequently, and the initial value of the phase of the local oscillation signals is set on the basis of the results of the judgment, so that a carrier can be reproduced in simple construction while preventing a hang-up phenomenon.

    摘要翻译: 复数乘法器5通过本地振荡信号c和s对从接收信号获得的基带信号x和y进行复数乘法,以输出复数检测信号p和q。 相位差检测部分7输出与接收信号的相位和本地振荡信号的相位之间的相位差相对应的检测到的相位差的量。 环路滤波器8强调其直流分量。 本地振荡部分6输出具有与检测到的相位差的量相对应的频率的本地振荡信号。 区域判断部9判断复平面上的哪个区域是基带信号所属的区域,并输出区域信号。 最频繁区域判断部分10判断哪个区域是其中基带信号在区域信号输入预定次数时最为集中的区域。 初始相位发生器11产生对应于最频繁区域的初始相位。 本地振荡部分6将初始相位设置为本地振荡信号的相位的初始值。 首先判断先前通过在复平面上划分获得的区域中的哪一个是复基带信号最集中地集中的区域,并且基于结果设置本地振荡信号的相位的初始值 的判断,使得能够以简单的结构再现载体,同时防止挂起现象。

    Adaptive array antenna
    6.
    发明授权
    Adaptive array antenna 有权
    自适应阵列天线

    公开(公告)号:US6107963A

    公开(公告)日:2000-08-22

    申请号:US442637

    申请日:1999-11-18

    IPC分类号: H01Q3/26 G01S3/16

    CPC分类号: H01Q3/2605

    摘要: An adaptive antenna includes a buffer for storing sample data obtained by sampling a receive signal, an information storage part for storing a plurality of sets of coefficients, an evaluation part for calculating an evaluation value of the result obtained by the coefficient and the sample data, a selection part for selecting two or more sets of coefficients in order of decreasing evaluation, an exchanging part for exchanging a part of coefficients between the selected sets of coefficients to generate a new set of coefficients, a changing part for changing a part of coefficients of the selected sets with random numbers to generate a new sets of coefficients, a reproduction part for reproducing the selected sets of coefficients as they are, and a determination part for outputting the result obtained by the set of coefficients with the highest evaluation value after the information storage part, the evaluation part, the selection part, the exchanging part, the changing part, and the reproduction part repeats respective operation once or more.

    摘要翻译: 自适应天线包括用于存储通过对接收信号进行采样得到的采样数据的缓冲器,用于存储多组系数的信息存储部分,用于计算由系数和采样数据获得的结果的评估值的评估部分, 选择部分,用于按照递减评估的顺序选择两组或多组系数;交换部分,用于交换所选择的系数集合中的一部分系数以产生一组新的系数;改变部分,用于改变部分系数 所选择的具有随机数的集合以生成新的系数集合,用于再现所选择的系数集合的再现部分,以及确定部分,用于输出在信息之后具有最高评估值的系数集合获得的结果 存储部分,评估部分,选择部分,交换部分,变化部分和可重复的部分 制作部分重复相应的操作一次或多次。