Space-time coded OFDM system for MMDS applications
    1.
    发明授权
    Space-time coded OFDM system for MMDS applications 有权
    用于MMDS应用的时空编码OFDM系统

    公开(公告)号:US07342875B2

    公开(公告)日:2008-03-11

    申请号:US10012066

    申请日:2001-11-05

    IPC分类号: G01R31/08

    CPC分类号: H04L27/2602 H04L1/0618

    摘要: A communications system includes a base station that is configured to transmit a signal that is modulated according to a predetermined modulation scheme and an orthogonal frequency division multiplexing scheme, wherein the signal is encoded using space-frequency coding. The base station includes a plurality of multiple-input multiple-output (MIMO) transceivers. The system includes a terminal that is configured to receive the modulated signal. The above arrangement is particularly applicable to providing multichannel multipoint distribution services (MMDS) over a radio communications system.

    摘要翻译: 通信系统包括:基站,被配置为发送根据预定调制方案和正交频分复用方案调制的信号,其中,使用空频编码来对信号进行编码。 基站包括多个多输入多输出(MIMO)收发器。 该系统包括被配置为接收调制信号的终端。 上述布置特别适用于通过无线电通信系统提供多信道多点分发业务(MMDS)。

    Combined interference cancellation with FEC decoding for high spectral efficiency satellite communications
    4.
    发明授权
    Combined interference cancellation with FEC decoding for high spectral efficiency satellite communications 有权
    用于高频谱效率卫星通信的FEC解码的组合干扰消除

    公开(公告)号:US06671338B1

    公开(公告)日:2003-12-30

    申请号:US09436670

    申请日:1999-11-10

    IPC分类号: H04B110

    摘要: A combined interference cancellation communication system employing forward error code (FEC) decoding for high spectral efficiency satellite communications. The disclosed system enables efficient utilization of available bandwidth through overlapping adjacent channels. A receiver is used to receive a waveform having data information and noise information. A filter bank is coupled with the receiver to receive and filter waveform and output channel information received by the receiver. The channel information received includes a combination of data signals and adjacent channel interference signals. Soft-input and soft-output decoders are provided to receive the channel information in order to calculate an estimated interference value. Additionally, the soft-input and soft-output interference canceler is provided for receiving the output channel information and the estimated interference value calculated from the decoders in order to provide a relatively more accurate estimated data signal. Typically, such systems employ remote ground terminals, e.g., VSAT, which are used for communicating via a geosynchronous satellite from a remote location to a central hub station or other remote locations. A particular advantage of the disclosed systems is their relatively low site cost and small earth station size.

    摘要翻译: 一种组合干扰消除通信系统,其采用用于高频谱效率卫星通信的前向纠错码(FEC)解码。 所公开的系统能够通过重叠相邻信道有效利用可用带宽。 接收机用于接收具有数据信息和噪声信息的波形。 滤波器组与接收器耦合以接收和滤波由接收器接收的波形和输出信道信息。 所接收的信道信息包括数据信号和相邻信道干扰信号的组合。 提供软输入和软输出解码器以接收信道信息,以便计算估计的干扰值。 此外,软输入和软输出干扰消除器被提供用于接收从解码器计算的输出信道信息和估计的干扰值,以便提供相对更准确的估计数据信号。 通常,这样的系统使用远程接地终端,例如VSAT,其用于经由地球同步卫星从远程位置到中心中心站或其他远程位置的通信。 所公开的系统的一个特别的优点是其相对较低的站点成本和小的地球站尺寸。

    System and method for combined predistortion and interference cancellation in a satellite communications system
    5.
    发明授权
    System and method for combined predistortion and interference cancellation in a satellite communications system 有权
    卫星通信系统中组合预失真和干扰消除的系统和方法

    公开(公告)号:US08355462B2

    公开(公告)日:2013-01-15

    申请号:US12608430

    申请日:2009-10-29

    IPC分类号: H04L25/03

    摘要: The present invention provides a communication system for use with a first source signal and a second source signal. The first source signal is on a first channel and includes M symbols, where M is an integer greater than 1. The second source signal is on a second channel and includes X symbols, where X is an integer greater than 1. The first channel is different from the second channel. The communication system includes a first modulator unit, a second modulator unit and an adder. The first modulator unit can generate a first modulated signal based on the first source signal and includes a first inter-symbol distortion estimating unit and a first stage predistortion unit. The second modulator unit can generate a second modulated signal based on the second source signal and includes a second inter-symbol distortion estimating unit and a predistortion unit. The adder can generate an added signal based on the first modulated signal and the second modulated signal. The first inter-symbol distortion estimating unit can generate a distorted symbol vector based on an estimate of a distortion of the first through (a−1)-th symbols and an estimate of a distortion of the (a+1)-th through M-th symbols, where 1≦a≦M. The first stage predistortion unit is operable to generate a predistorted symbol ã based on the symbol a of the first plurality of symbols and the distorted symbol vector. Further, a receiver unit can cancel interference in the received signals to account for adjacent channel interference.

    摘要翻译: 本发明提供一种与第一源信号和第二源信号一起使用的通信系统。 第一源信号在第一信道上并且包括M个符号,其中M是大于1的整数。第二源信号在第二信道上并且包括X个符号,其中X是大于1的整数。第一信道是 不同于第二通道。 通信系统包括第一调制器单元,第二调制器单元和加法器。 第一调制器单元可以基于第一源信号产生第一调制信号,并且包括第一符号间失真估计单元和第一级预失真单元。 第二调制器单元可以基于第二源信号生成第二调制信号,并且包括第二符号间失真估计单元和预失真单元。 加法器可以基于第一调制信号和第二调制信号产生相加的信号。 第一符号间失真估计单元可以基于第一到第(a-1)个符号的失真的估计和第(a + 1)至第M个符号的失真的估计来生成失真的符号向量 第一个符号,其中1≦̸ a≦̸ M。 第一级预失真单元可操作以基于第一多个符号的符号a和失真的符号向量生成预失真符号ã。 此外,接收机单元可以消除接收到的信号中的干扰以解决相邻信道干扰。

    SYSTEM AND METHOD FOR COMBINED PREDISTORTION AND INTERFERENCE CANCELLATION IN A SATELLITE COMMUNICATIONS SYSTEM
    6.
    发明申请
    SYSTEM AND METHOD FOR COMBINED PREDISTORTION AND INTERFERENCE CANCELLATION IN A SATELLITE COMMUNICATIONS SYSTEM 有权
    在卫星通信系统中组合预测和干扰消除的系统和方法

    公开(公告)号:US20110103507A1

    公开(公告)日:2011-05-05

    申请号:US12608430

    申请日:2009-10-29

    IPC分类号: H04B15/00 H04L25/03

    摘要: The present invention provides a communication system for use with a first source signal and a second source signal. The first source signal is on a first channel and includes M symbols, where M is an integer greater than 1. The second source signal is on a second channel and includes X symbols, where X is an integer greater than 1. The first channel is different from the second channel. The communication system includes a first modulator unit, a second modulator unit and an adder. The first modulator unit can generate a first modulated signal based on the first source signal and includes a first inter-symbol distortion estimating unit and a first stage predistortion unit. The second modulator unit can generate a second modulated signal based on the second source signal and includes a second inter-symbol distortion estimating unit and a predistortion unit. The adder can generate an added signal based on the first modulated signal and the second modulated signal. The first inter-symbol distortion estimating unit can generate a distorted symbol vector based on an estimate of a distortion of the first through (a−1)-th symbols and an estimate of a distortion of the (a+1)-th through M-th symbols, where 1≦a≦M. The first stage predistortion unit is operable to generate a predistorted symbol ã based on the symbol a of the first plurality of symbols and the distorted symbol vector. Further, a receiver unit can cancel interference in the received signals to account for adjacent channel interference.

    摘要翻译: 本发明提供一种与第一源信号和第二源信号一起使用的通信系统。 第一源信号在第一信道上并且包括M个符号,其中M是大于1的整数。第二源信号在第二信道上并且包括X个符号,其中X是大于1的整数。第一信道是 不同于第二通道。 通信系统包括第一调制器单元,第二调制器单元和加法器。 第一调制器单元可以基于第一源信号产生第一调制信号,并且包括第一符号间失真估计单元和第一级预失真单元。 第二调制器单元可以基于第二源信号生成第二调制信号,并且包括第二符号间失真估计单元和预失真单元。 加法器可以基于第一调制信号和第二调制信号产生相加的信号。 第一符号间失真估计单元可以基于第一到第(a-1)个符号的失真的估计和第(a + 1)至第M个符号的失真的估计来生成失真的符号向量 第一个符号,其中1≦̸ a≦̸ M。 第一级预失真单元可操作以基于第一多个符号的符号a和失真的符号向量生成预失真符号ã。 此外,接收机单元可以消除接收到的信号中的干扰以解决相邻信道干扰。

    Method and apparatus for acquiring a synchronization signal

    公开(公告)号:US07042854B2

    公开(公告)日:2006-05-09

    申请号:US09768726

    申请日:2001-01-24

    IPC分类号: H04B7/212

    摘要: A method and system for acquiring a time division multiplexed synchronization signal in a satellite communication system is provided. The signal is provided as a series of frames with beacon signals time division multiplexed into at least one time slot of each frame. The beacon signal in each frame comprises a unique word sequence, which is the same in each frame, and a portion of a PN sequence. The entire PN sequence is distributed into a plurality of frames forming a superframe. Initially, the power level of the incoming signal is determined by locating the maximum power received in half time slot intervals. Next a series of frames are correlated against the expected unique word, each at one of a plurality of possible frequencies. The frequency generating the maximum correlation with the unique word is selected. The frequency is fine tuned by comparing the actual arrival time of the unique word in each frame with the estimated arrival time based on the current frequency, and adjusting the frequency accordingly. Also, the start of the superframe is located by correlating the PN sequence portion of each beacon signal against a known PN sequence until a match is found. Once the frequency offset is reduced below a threshold value, and the start of the PN sequence of the incoming signal is located, acquisition is completed.

    Method and apparatus for tracking a synchronization signal

    公开(公告)号:US07012937B2

    公开(公告)日:2006-03-14

    申请号:US09768728

    申请日:2001-01-24

    IPC分类号: H04J3/06

    摘要: A method and system for tracking a time division multiplexed synchronization signal in a satellite communication system is provided. The signal is provided as a series of frames with beacon signals time division multiplexed into at least one time slot of each frame. The beacon signal in each frame comprises a unique word sequence, which is the same in each frame, and a portion of a PN sequence. The entire PN sequence is distributed into a plurality of frames forming a superframe. Frequency variations of the incoming signal are tracked at the satellite terminal by correlating the PN sequence of the incoming signal against early and late locally generated versions of the PN sequence in a discriminate circuit. The output of the discriminate is provided to a delay locked loop circuit of at least third order. The output of the loop is used to adjust the frequency of the VCO, which clocks the A/D converter operating on the incoming signal. The product of the PN sequence of the incoming signal and an on-time locally generated version of the PN sequence is provided to an FFT circuit. The satellite terminal determines if it is locked onto the incoming signal based on the output of the FFT. If the satellite terminal is not locked, the terminal returns to an acquisition mode.

    System and method for compensating for nonlinear interference cancellation in multi-carrier transmission
    9.
    发明授权
    System and method for compensating for nonlinear interference cancellation in multi-carrier transmission 有权
    用于补偿多载波传输中的非线性干扰消除的系统和方法

    公开(公告)号:US08331511B2

    公开(公告)日:2012-12-11

    申请号:US12637154

    申请日:2009-12-14

    IPC分类号: H04B1/00

    CPC分类号: H04B1/126 H04L25/03038

    摘要: An aspect of the present invention is drawn to a receiver operable to receive a first signal transmitted on a first carrier and to receive a second signal transmitted on a second carrier. The receiver includes a first filter, a second filter and a nonlinear compensator. The first filter is arranged to receive the first signal and to generate a first filtered signal. The second filter is arranged to receive the second signal and to generate a second filtered signal. The nonlinear compensator is arranged to output a first compensating signal based on the first filtered signal and the second filtered signal and to output a second compensating signal based on the first filtered signal and the second filtered signal. Further, the nonlinear compensator can reduce one of nonlinear interference within the first filtered signal and nonlinear interference between the first filtered signal and the second filtered signal.

    摘要翻译: 本发明的一个方面涉及一种可操作以接收在第一载波上发送的第一信号并且接收在第二载波上发送的第二信号的接收机。 接收机包括第一滤波器,第二滤波器和非线性补偿器。 第一滤波器被布置成接收第一信号并产生第一滤波信号。 第二滤波器被布置成接收第二信号并产生第二滤波信号。 非线性补偿器被布置为基于第一滤波信号和第二滤波信号输出第一补偿信号,并且基于第一滤波信号和第二滤波信号输出第二补偿信号。 此外,非线性补偿器可以减少第一滤波信号内的非线性干扰之一和第一滤波信号与第二滤波信号之间的非线性干扰。