Iterative time-frequency domain transform method for filtering
time-varying, nonstationary wide band signals in noise
    1.
    发明授权
    Iterative time-frequency domain transform method for filtering time-varying, nonstationary wide band signals in noise 失效
    用于对噪声中的时变,非平稳宽带信号进行滤波的迭代时域变换方法

    公开(公告)号:US5852567A

    公开(公告)日:1998-12-22

    申请号:US695321

    申请日:1996-07-31

    CPC分类号: H04B1/10 H04L27/0004

    摘要: An iterative time frequency algorithm filters noisy wide band/nonstationary signals by projecting the noisy signal into the TF domain, masking the TF response, computing the inverse TF transform to extract a filtered signal, and repeating these steps until the projection lies within the mask. As a result, the TF domain properties of the extracted signal are substantially equal to the desired TF domain properties. Furthermore, the iterative approach is computationally simple because it avoids inverting matrices. The TF transform and its inverse must be selected such that the iterative algorithm is guaranteed to converge. Candidate transform pairs can be tested on known data, and if the TF transforms converge to the desired TF properties, the candidate pair can be selected. Alternately, the candidate pairs can be tested against a sufficient convergence condition, and if they satisfy the condition within an acceptable tolerance, they can be selected with confidence. Furthermore, the sufficient convergence condition can be solved directly to provide the TF transform and its inverse.

    摘要翻译: 迭代时间频率算法通过将有噪声信号投射到TF域中来掩蔽TF响应,计算逆TF变换以提取滤波信号,并重复这些步骤,直到投影位于掩模内,来对噪声宽带/非平稳信号进行滤波。 结果,提取的信号的TF结构域性质基本上等于期望的TF结构域性质。 此外,迭代方法在计算上是简单的,因为它避免了反相矩阵。 必须选择TF变换及其逆,使迭代算法保证收敛。 可以对已知数据测试候选变换对,如果TF变换收敛到期望的TF属性,则可以选择候选对。 或者,可以针对足够的收敛条件来测试候选对,并且如果它们满足可接受的容限内的条件,则可以置信地选择候选对。 此外,可以直接解决足够的收敛条件,以提供TF变换及其逆。

    Precoded OFDM systems robust to spectral null channels and vector OFDM systems with reduced cyclic prefix length
    2.
    发明授权
    Precoded OFDM systems robust to spectral null channels and vector OFDM systems with reduced cyclic prefix length 失效
    具有减少循环前缀长度的频谱零通道和向量OFDM系统鲁棒的预编码OFDM系统

    公开(公告)号:US06928047B1

    公开(公告)日:2005-08-09

    申请号:US09658184

    申请日:2000-09-08

    申请人: Xiang-Gen Xia

    发明人: Xiang-Gen Xia

    摘要: A precoded orthogonal frequency division multiplexer (OFDM) system that improves the preformance of OFDM systems for spectral null channels, and size K×1 vector OFDM systems that reduce the cyclic prefix length by K times compared to conventional OFDM systems. The precoding scheme comprises inserting one or more zeros between each of the two sets of K consecutive information symbols, although it can be generalized to a general form. This precoding scheme removes the spectral nulls of an ISI channel without knowing the ISI channel. When no zero is inserts between each of the two sets of K consecutive information symbols and only K consecutive symbols are blocked together, vector OFDM systems are obtained. The bit error rate performance of the vector OFDM systems of the present invention is much improved over conventional OFDM systems.

    摘要翻译: 一种预编码的正交频分复用器(OFDM)系统,其改进了用于频谱空信道的OFDM系统的预处理,以及与常规OFDM系统相比减小循环前缀长度K倍的K×1向量OFDM系统。 预编码方案包括在两组K个连续信息符号中的每一个之间插入一个或多个零,尽管可以将其概括为一般形式。 该预编码方案在不知道ISI信道的情况下去除ISI信道的频谱零点。 当两个K个连续信息符号中的每一个之间不插入零时,并且只有K个连续符号被一起阻塞,则获得向量OFDM系统。 本发明的向量OFDM系统的比特误码率性能比传统的OFDM系统大大改进。

    Watermarking methods for digital images and videos
    3.
    发明授权
    Watermarking methods for digital images and videos 失效
    数字图像和视频的水印方法

    公开(公告)号:US06556689B1

    公开(公告)日:2003-04-29

    申请号:US09295426

    申请日:1999-04-20

    IPC分类号: G06K900

    摘要: The present invention relates to multiresolution watermarking methods for digital images which are based on a discrete wavelet transform (DWT). Pseudo-random codes are added to the large coefficients located at the high and middle frequency bands of the DWT of a digital image. A peak is detected to signify a signature of the watermark. The methods taught herein are more robust then conventional methods for common image distortions, such as the wavelet transform based image compression, additive noise, image halftoning, and image resealing. Moreover, the method is hierarchal. The computational load needed to detect the watermark depends on the noise level in an image. The multiresolution and hierarchial watermarking method taught by the present invention results in lower computational loads, on average, while providing a high quality watermark which is utilizable with modern image/video compression standards.

    摘要翻译: 本发明涉及基于离散小波变换(DWT)的数字图像的多分辨率水印方法。 伪随机码被添加到位于数字图像的DWT的高和中频带的大系数中。 检测到峰值以表示水印的签名。 本文教导的方法对于常见的图像失真(例如基于小波变换的图像压缩,附加噪声,图像半色调和图像重新密封)的常规方法更为鲁棒。 此外,该方法是分层的。 检测水印所需的计算负荷取决于图像中的噪声水平。 本发明教导的多分辨率和分层水印方法平均得到较低的计算量,同时提供可利用现代图像/视频压缩标准的高质量水印。

    Object-based video coding of arbitrarily shaped objects using lapped
orthogonal transforms (LOTs) defined on rectangular and L-shaped regions
    4.
    发明授权
    Object-based video coding of arbitrarily shaped objects using lapped orthogonal transforms (LOTs) defined on rectangular and L-shaped regions 失效
    使用在矩形和L形区域上定义的重叠正交变换(LOT)的任意形状对象的基于对象的视频编码

    公开(公告)号:US6014466A

    公开(公告)日:2000-01-11

    申请号:US891083

    申请日:1997-07-10

    CPC分类号: G06T9/007

    摘要: An object-based image/video coding algorithm that encodes arbitrary shaped objects using LOTs defined on rectangular and L-shaped regions. The regions of support of the blocks in the L-shaped regions are extended to form tapered overlapping regions that meet at the object's exterior and concave corners. The overlapping regions taper to the corners with a slope having a magnitude .delta./.epsilon., where .delta. and .epsilon. are the amounts of overlap between the blocks. This allows the basis and tapered window functions to be defined in the L-shaped region and specifically in the tapered overlapping regions in a manner that maintains the orthogonality of the basis functions while providing a smooth transition at the edges.

    摘要翻译: 一种基于对象的图像/视频编码算法,其使用在矩形和L形区域上定义的LOT来编码任意形状的对象。 在L形区域中的块的支撑区域被延伸以形成在物体的外部和凹角处相遇的锥形重叠区域。 重叠区域以具有幅度δ/ε的斜率渐变到角部,其中δ和ε是块之间的重叠量。 这允许在L形区域,特别是在锥形重叠区域中以基本功能的正交性定义基础和渐缩窗口功能,同时在边缘处提供平滑过渡。

    Vector trellis coded modulation using vector convolutional codes for
reliable data transmission
    5.
    发明授权
    Vector trellis coded modulation using vector convolutional codes for reliable data transmission 失效
    矢量网格编码调制使用矢量卷积码进行可靠的数据传输

    公开(公告)号:US5809082A

    公开(公告)日:1998-09-15

    申请号:US673715

    申请日:1996-06-21

    申请人: Xiang-Gen Xia

    发明人: Xiang-Gen Xia

    CPC分类号: H03M13/25

    摘要: A vector trellis coded modulation scheme (VTCM) is accomplished by blocking input samples into a sequence of input vectors of length L, vector convolutional coding the input vectors to map K input vectors into N output vectors and modulating the output vectors into symbols from an expanded alphabet. In a first case, each output vector is modulated to a different symbol thereby improving coding gain while maintain bandwidth efficiency. In a second case, blocks of N output vectors are modulated to one symbol thereby improving bandwidth efficiency by a factor of N while maintain coding gain. A polyphase/multirate representation of the vector convolutional codes is preferably used to generated the vector convolutional codes. In general, a computer search can be employed to find the polyphase coefficients that define the set of vector convolutional codes. When the input and output vectors have the same length, known scalar-valued convolutional codes are blocked to generate the vector convolutional codes. This provides good modulation codes without having to perform a computer search.

    摘要翻译: 矢量网格编码调制方案(VTCM)通过将输入样本阻塞到长度为L的输入向量的序列中来完成,矢量卷积编码输入向量,以将K个输入向量映射为N个输出向量,并将输出向量调制为扩展的符号 字母。 在第一种情况下,将每个输出矢量调制成不同的符号,从而在维持带宽效率的同时提高编码增益。 在第二种情况下,将N个输出矢量的块调制为一个符号,从而在保持编码增益的同时将带宽效率提高N倍。 优选地使用向量卷积码的多相/多速率表示来生成向量卷积码。 通常,可以使用计算机搜索来找出定义向量卷积码集合的多相系数。 当输入和输出向量具有相同的长度时,已知的标量卷积码被阻塞以产生向量卷积码。 这提供了良好的调制码,而无需执行计算机搜索。

    Quasi-orthogonal space-time block encoder, decoder and methods for space-time encoding and decoding orthogonal frequency division multiplexed signals in a multiple-input multiple-output system
    6.
    发明授权
    Quasi-orthogonal space-time block encoder, decoder and methods for space-time encoding and decoding orthogonal frequency division multiplexed signals in a multiple-input multiple-output system 失效
    准正交空时块编码器,解码器和多输入多输出系统中时空编码和解码正交频分复用信号的方法

    公开(公告)号:US08457231B2

    公开(公告)日:2013-06-04

    申请号:US12447026

    申请日:2006-10-24

    IPC分类号: H04L1/02 H04L27/28

    摘要: Embodiments of quasi-orthogonal space-time encoder, decoder and method for space-time encoding and decoding orthogonal frequency division multiplexed (OFDM) signals in a multiple-input multiple-output (MDMO) system are generally described herein. Other embodiments may be described and claimed. In some embodiments, a method of decoding received multicarrier signals comprises deriving objective functions from a received signal matrix, minimizing the objective functions to generate decoded hard bits, and solving a set of linear equations of the objective functions to generate decoded soft bits.

    摘要翻译: 在这里通常描述在多输入多输出(MDMO)系统中的准正交时空编码器,解码器和时空编码和解码正交频分复用(OFDM)信号的实施例。 可以描述和要求保护其他实施例。 在一些实施例中,解码所接收的多载波信号的方法包括从接收信号矩阵导出目标函数,使目标函数最小化以产生解码的硬比特,以及求解目标函数的一组线性方程以产生解码的软比特。

    QUASI-ORTHOGONAL SPACE-TIME BLOCK ENCODER, DECODER AND METHODS FOR SPACE-TIME ENCODING AND DECODING ORTHOGONAL FREQUENCY DIVISION MULTIPLEXED SIGNALS IN A MULTIPLE-INPUT MULTIPLE-OUTPUT SYSTEM
    7.
    发明申请
    QUASI-ORTHOGONAL SPACE-TIME BLOCK ENCODER, DECODER AND METHODS FOR SPACE-TIME ENCODING AND DECODING ORTHOGONAL FREQUENCY DIVISION MULTIPLEXED SIGNALS IN A MULTIPLE-INPUT MULTIPLE-OUTPUT SYSTEM 失效
    正交正交空间编码器,解码器和方法,用于空间编码和解码多路输入多输出系统中的正交频分多址信号

    公开(公告)号:US20100086080A1

    公开(公告)日:2010-04-08

    申请号:US12447026

    申请日:2006-10-24

    IPC分类号: H04L27/36 H04L27/00 H04L27/06

    摘要: Embodiments of quasi-orthogonal space-time encoder, decoder and method for space-time encoding and decoding orthogonal frequency division multiplexed (OFDM) signals in a multiple-input multiple-output (MDMO) system are generally described herein. Other embodiments may be described and claimed. In some embodiments, a method of decoding received multicarrier signals comprises deriving objective functions from a received signal matrix, minimizing the objective functions to generate decoded hard bits, and solving a set of linear equations of the objective functions to generate decoded soft bits.

    摘要翻译: 在这里通常描述在多输入多输出(MDMO)系统中的准正交时空编码器,解码器和时空编码和解码正交频分复用(OFDM)信号的实施例。 可以描述和要求保护其他实施例。 在一些实施例中,解码所接收的多载波信号的方法包括从接收信号矩阵导出目标函数,使目标函数最小化以产生解码的硬比特,以及求解目标函数的一组线性方程以产生解码的软比特。

    Digital wireless communications systems that eliminates intersymbol interference (ISI) and multipath cancellation using a plurality of optimal ambiguity resistant precoders
    8.
    发明授权
    Digital wireless communications systems that eliminates intersymbol interference (ISI) and multipath cancellation using a plurality of optimal ambiguity resistant precoders 失效
    数字无线通信系统消除符号间干扰(ISI)和多路径消除使用多个最佳模糊抵抗预编码器

    公开(公告)号:US06493399B1

    公开(公告)日:2002-12-10

    申请号:US09261294

    申请日:1999-03-02

    IPC分类号: H04L2549

    CPC分类号: H04L1/06 H04L25/03343

    摘要: A digital wireless communications system which eliminates intersymbol interference in a transmitted signal using a plurality of precoders in a transmitter thereof and a method of using the same. The digital wireless communications system includes a receiver having an antenna array for receiving transmitted digitally-encoded signals, and a transmitter for transmitting the digitally-encoded signals. The transmitter has a plurality of precoders which eliminate intersymbol interference in the transmitted signals such that the receiver recovers digital information from the transmitted signals which is free from intersymbol interference. Ambiguity resistant (AR) precoding has been recently proposed in intersymbol interference (ISI) and multipath cancellations, where the ISI/multipath channel may have frequency-selective fading characteristics and its knowledge is not necessarily known. With the AR precoding, no diversity is necessary at the receiver. In the precoding, the AR property for a precoder plays an important rule. In this paper. more families and properties of AR precoders are presented and characterized. In particular. all systematic AR precoders are characterized. More importantly, the concepts of precoder distance and optimal precoders are introduced and characterized, enabling construction of all optimal systematic AR precoders when additive channel random noise is concerned. A necessary and sufficient condition for an AR precoder to be optimal is provided which is easy to check. Numerical examples are also presented to show the improved performance over the known AR precoders in ISI cancellation applications.

    摘要翻译: 一种数字无线通信系统,其使用其发射机中的多个预编码器来消除发射信号中的符号间干扰及其使用方法。 数字无线通信系统包括具有用于接收发送的数字编码信号的天线阵列的接收机和用于发送数字编码信号的发射机。 发射机具有多个预编码器,其消除发射信号中的符号间干扰,使得接收机从没有符号间干扰的发射信号中恢复数字信息。 近来在符号间干扰(ISI)和多路径消除中提出了模糊抗拒(AR)预编码,其中ISI /多路径信道可能具有频率选择性衰落特性,并且其知识不一定是已知的。 使用AR预编码,接收机不需要分集。 在预编码中,预编码器的AR属性起着重要的作用。 在本文中。 呈现和表征了AR预编码器的更多家族和性质。 尤其是。 所有系统的AR预编码器都是特征。 更重要的是,引入了预编码器距离和最优预编码器的概念,并且对其进行了特征化,使得在加入频道随机噪声时能够构建所有最优的系统AR编码器。 提供了AR预编码器最佳的必要和充分条件,易于检查。 还提供了数字示例,以显示ISI取消应用中已知AR预编码器的性能提高。

    CDMA code generator employing mixing ergodic transformation
    9.
    发明授权
    CDMA code generator employing mixing ergodic transformation 失效
    CDMA码发生器采用混合遍历转换

    公开(公告)号:US5726658A

    公开(公告)日:1998-03-10

    申请号:US657250

    申请日:1996-06-03

    CPC分类号: G01S7/36 G01S13/106 H04B1/69

    摘要: A codeword generator produces codewords in the form of digital electronic signals which may be employed, for example, in spread spectrum communications system or RADAR systems. The generator effects a mixing ergodic transformation upon a suitable irrational number to produce a complex number sequence. The generator truncates the complex number sequence to a predetermined length, thus forming a codeword. The generator then forms other codewords within a family by permuting this first codeword. Other families of codewords may be generated by employing another mixing ergodic transform to transform the same irrational number or another suitable irrational number.

    摘要翻译: 码字生成器产生数字电子信号形式的码字,其可以用于例如扩频通信系统或RADAR系统中。 发生器对合适的无理数进行混合遍历转换,以产生复数序列。 发生器将复数序列截断为预定长度,从而形成码字。 然后,发生器通过置换该第一码字在家庭内形成其他码字。 可以通过使用另一种混合遍历变换来转换相同的无理数或另一合适的无理数来产生码字的其他族。