公开(公告)号：US6002726A

公开(公告)日：1999-12-14

申请号：US975997

申请日：1997-11-21

Applicant: Sivanand Simanapalli ,  Xiao-An Wang

Inventor： Sivanand Simanapalli ,  Xiao-An Wang

IPC: H03D3/00 ,  H04L27/14 ,  H04L27/08 ,  G06F7/52

CPC classification number: H04L27/14 ,  H03D3/007

Abstract: A method of extracting an information bearing signal .omega.(n) from a base-band signal in the form of an inverse function with a digital signal processor. The processor includes memory and utilizes a minimum number of instructions stored in the memory. The base-band waveform comprises a plurality of complex-valued samples having respective I and Q components. The method includes the steps of receiving a first sample at an instant n having respective I(n) and Q(n) components and defining an interval for evaluating potential values for the I(n) and Q(n) components. Next, a step of transforming said I(n) and Q(n) components is performed to have respective threshold values residing in the predefined interval. Then, a step of estimating the transformed components with a series of non-inverted polynomial functions is carried out over the predefined interval. The method proceeds by extracting the information-bearing signal with the digital signal processor according to the instructions to evaluate the series of non-inverted polynomial functions.

Abstract translation: 一种从数字信号处理器的反函数形式的基带信号中提取信息承载信号ω（n）的方法。 处理器包括存储器并利用存储在存储器中的最少数目的指令。 基带波形包括具有相应I和Q分量的多个复值样本。 该方法包括以下步骤：在具有相应的I（n）和Q（n）分量的时刻n接收第一采样，并且定义用于评估I（n）和Q（n）分量的电位值的间隔。 接下来，执行变换所述I（n）和Q（n）分量的步骤以具有驻留在预定间隔中的相应阈值。 然后，在预定义的间隔内执行用一系列非反相多项式函数估计变换分量的步骤。 该方法通过根据指令提取具有数字信号处理器的信息承载信号来评估一系列非反相多项式函数。

公开(公告)号：US10454664B2

公开(公告)日：2019-10-22

申请号：US15869042

申请日：2018-01-12

Applicant: Xiao-an Wang

Inventor： Xiao-an Wang

IPC: H04L5/14 ,  H04W72/04 ,  H04W56/00 ,  H04L5/00 ,  H04B7/0452 ,  H04W88/08

Abstract: Multipoint broadcasting relying on channel reciprocity in a TDD network requires that the broadcasters be calibrated. In the cases where the relative amplitude profiles and nonlinear phases are time-invariant or slow-varying, broadcaster calibration reduces to phase synchronization. Methods and apparatus are described that provide broadcaster calibration and phase synchronization with terminal feedback and overcome the drawbacks of self-calibration. The methods and apparatus are capable of calibrating hundreds of broadcaster antennas in massive antenna applications while maintaining an extremely low overhead. Applications of the described methods and apparatus include multipoint broadcasting in wireless networks, also known as coordinated multipoint transmission, or CoMP, in LTE-A (long-term evolution, advanced) networks, and distributed MIMO, massive MIMO, massive beamforming, etc., in other networks including 5G and 802.11. Applications also include frequency and phase synchronization of a cluster of wireless devices.

公开(公告)号：US20190222406A1

公开(公告)日：2019-07-18

申请号：US15869042

申请日：2018-01-12

Applicant: Xiao-an Wang

Inventor： Xiao-an Wang

IPC: H04L5/14 ,  H04W72/04 ,  H04L5/00 ,  H04W56/00

Abstract: Multipoint broadcasting relying on channel reciprocity in a TDD network requires that the broadcasters be calibrated. In the cases where the relative amplitude profiles and nonlinear phases are time-invariant or slow-varying, broadcaster calibration reduces to phase synchronization. Methods and apparatus are described that provide broadcaster calibration and phase synchronization with terminal feedback and overcome the drawbacks of self-calibration. The methods and apparatus are capable of calibrating hundreds of broadcaster antennas in massive antenna applications while maintaining an extremely low overhead. Applications of the described methods and apparatus include multipoint broadcasting in wireless networks, also known as coordinated multipoint transmission, or CoMP, in LTE-A (long-term evolution, advanced) networks, and distributed MIMO, massive MIMO, massive beamforming, etc., in other networks including 5G and 802.11. Applications also include frequency and phase synchronization of a cluster of wireless devices.

公开(公告)号：US09137077B2

公开(公告)日：2015-09-15

申请号：US13293813

申请日：2011-11-10

Applicant: Xiao-an Wang

Inventor： Xiao-an Wang

IPC: H04B1/00 ,  H04L27/26 ,  H04L25/02 ,  H04L5/00 ,  H04L25/03

CPC classification number: H04L27/2613 ,  H04L5/0016 ,  H04L5/0023 ,  H04L5/0035 ,  H04L5/0048 ,  H04L25/0204 ,  H04L25/0224 ,  H04L2025/03426

Abstract: Large-dimension MIMO and multipoint broadcasting in new generation of wireless networks create high demand for various types of pilots in transmission signals for channel estimation, data demodulation, synchronization, etc. More pilots, as in existing networks, use more resources and thus diminish the network capacity. Methods and apparatus of heterogeneous pilots are disclosed. A heterogeneous pilot has its own signal characteristics that are different from the primary information-bearing signals in the network. Heterogeneous pilots can be spread-spectrum signals in an OFDM-based wireless network. Heterogeneous pilots use no network resources, and can be as many as desired, and can be designed to have versatile utilities. Also described are methods and apparatus of heterogeneous pilot cancellation that minimizes the interference of heterogeneous pilots on the primary information-bearing signals. Applications of the described methods and apparatus include OFDM-based wireless cellular networks, such as LTE-advanced and Wireless LAN.

Abstract translation: 新一代无线网络中的大尺寸MIMO和多点广播对于信道估计，数据解调，同步等传输信号中的各种类型的导频产生了高需求。如现有网络中更多的飞行员使用更多的资源，从而减少 网络容量。 披露了异质飞行员的方法和装置。 异构导频具有与网络中的主要信息承载信号不同的信号特征。 异构导频可以是基于OFDM的无线网络中的扩频信号。 异构飞行员不使用网络资源，并且可以根据需要而设计，并且可以被设计为具有通用的实用程序。 还描述了使异构导频对主要信息承载信号的干扰最小化的异构导频消除的方法和装置。 所描述的方法和装置的应用包括基于OFDM的无线蜂窝网络，诸如LTE高级和无线LAN。

公开(公告)号：US09125074B2

公开(公告)日：2015-09-01

申请号：US13854130

申请日：2013-03-31

Applicant: Xiao-an Wang

Inventor： Xiao-an Wang

IPC: H04W24/02 ,  H04B7/04 ,  H04W16/28 ,  H04B7/02

CPC classification number: H04W24/02 ,  H04B7/024 ,  H04B7/0452 ,  H04W16/28

Abstract: MU-MIMO and CoMP have potentials to increase the cell capacity by many folds. Interferences and channel feedback overhead, however, severely limits such potentials. Method of reference signal-based grid of beams (RS-GOB) is described. RS-GOB distributes the effective antennas of a base station into multiple beams, thereby significantly reducing the feedback overhead of CoMP and making effective use of CoMP to turn the interferences into cooperating useful signals. RS-GOB also reduces the need for small HetNet cells, which mitigates the interferences of small HetNet cells on macro cells.

Abstract translation: MU-MIMO和CoMP具有将细胞容量增加许多倍的潜力。 然而，干扰和渠道反馈开销严重限制了这种潜力。 描述了基于信号的光束网格（RS-GOB）的方法。 RS-GOB将基站的有效天线分配到多个波束中，从而大大减少了CoMP的反馈开销，并有效利用了CoMP将干扰转化为合作的有用信号。 RS-GOB还减少了对小型HetNet电池的需求，从而减轻了小型HetNet电池在宏电池上的干扰。

公开(公告)号：US08705647B2

公开(公告)日：2014-04-22

申请号：US13087943

申请日：2011-04-15

Applicant: Xiao-an Wang

Inventor： Xiao-an Wang

IPC: H04B7/02

CPC classification number: H04L25/0328 ,  H04L25/03292 ,  H04L25/03331 ,  H04L25/03891

Abstract: A method is described that enables maximum-likelihood (ML) demodulation for MIMO communications over frequency-selective channels. An equalizer is typically employed to suppress inter-symbol interference (ISI) due to frequency-selectiveness of the channel, but the noise of the equalizer output can be highly correlated such that standard ML-MIMO demodulations cannot directly apply. The method comprises first constructing equivalent post-equalization MIMO channel and noise covariance matrix, and then de-correlating the equalizer output so that ML or near-ML MIMO demodulations can be applied to improve the performance. Additionally, successive ISI cancellation (SIC) is described for further performance improvement.

Abstract translation: 描述了一种能够通过频率选择信道进行MIMO通信的最大似然（ML）解调的方法。 通常采用均衡器来抑制由于信道的频率选择性引起的符号间干扰（ISI），但是均衡器输出的噪声可以高度相关，使得标准ML-MIMO解调不能直接应用。 该方法包括首先构建等效的后均衡MIMO信道和噪声协方差矩阵，然后将均衡器输出去相关，使ML或近ML MIMO解调可以应用于提高性能。 另外，为了进一步提高性能，描述了连续的ISI取消（SIC）。

公开(公告)号：US06639955B1

公开(公告)日：2003-10-28

申请号：US09376852

申请日：1999-08-18

Applicant: Xiao-An Wang

Inventor： Xiao-An Wang

IPC: H03D104

CPC classification number: H04B17/3911

Abstract: A system employs a modified Jakes' fading model to generate a fading signal having substantially equivalent autocorrelation values for in-phase (I) and quadrature-phase (Q) components. A Walsh transform may be applied to generate multiple, uncorrelated I and Q components, for multiple fading signals. A complex Rayleigh fading signal according to the modified complex Jakes fading model is provided by a generator having M pairs of I and Q paths. Each pair of I and Q paths includes a corresponding complex carrier generator 201 (M an integer and 1≦n≦M) generating a complex carrier signal with frequency, &ohgr;n, where &ohgr;n is cos ((4n−3&pgr;)/4M). Each of the I paths has a circuit that separates the real component of the corresponding carrier signal to provide a real carrier signal cos (&ohgr;nt). Similarly, each of the Q paths has a circuit that separates the imaginary component of the corresponding complex carrier signal to provide an imaginary carrier signal sin (&ohgr;nt). The M output signals of the circuits for the I-paths may be summed in a corresponding adder to provide in-phase component rI(t) of the fading signal r(t). Similarly, the M output signals of the circuits for the Q-paths may be summed in a corresponding adder to provide the quadrature component rQ(t) of the fading signal r(t).

Abstract translation: 系统采用经修改的Jakes衰落模型来产生具有基本等效的自相关值的衰落信号，用于同相（I）和正交相（Q）分量。 对于多个衰落信号，可以应用沃尔什变换来产生多个不相关的I和Q分量。 根据经修改的复合抖动衰落模型的复数瑞利衰落信号由具有M对I和Q路径的发生器提供。 每对I和Q路径包括产生频率ωgan的复数载波信号的对应的复数载波发生器201（M为整数，1≤n≤M），其中ω为cos（（4n-3pi）/ 4M） 。 I路径中的每一个具有分离相应载波信号的实部分量以提供实际载波信号cos（ω）的电路。 类似地，Q路径中的每一个具有分离对应的复载波信号的虚分量以提供假载波信号sin（ω）的电路。 用于I-path的电路的M个输出信号可以在相应的加法器中相加，以提供衰落信号r（t）的同相分量rI（t）。 类似地，用于Q路径的电路的M个输出信号可以在相应的加法器中相加，以提供衰落信号r（t）的正交分量rQ（t）。

公开(公告)号：US06633615B1

公开(公告)日：2003-10-14

申请号：US09495161

申请日：2000-01-31

Applicant: Steven P. Pekarich ,  Xiao-An Wang

Inventor： Steven P. Pekarich ,  Xiao-An Wang

IPC: H04L512

CPC classification number: H04L1/006 ,  H03M13/41 ,  H03M13/6343 ,  H03M13/6502 ,  H03M13/6583 ,  H04L1/0054

Abstract: A circuit performs threshold normalization of accumulated transition probabilities for a given state of a state transition trellis in a maximum likelihood detector. Threshold normalization may be accomplished by comparison and setting of a single bit in stored transition probabilities. Threshold value comparison may be accomplished by comparing the bth bit of the stored transition probabilities if the threshold value is 2b. When all transition probabilities exceed the threshold value at a stage of the trellis, the transition probabilities are scaled, such as by subtracting the threshold value. Scaling may be implemented by setting the compared bth bits to zero before storage. In general, since accumulated transition probabilities are monotonically increasing for transition probabilities of paths through the trellis in both forward and reverse directions, the present invention may be employed for both threshold normalization of both the forward (&agr;) and reverse (&bgr;) transition probabilities.

Abstract translation: 电路对最大似然检测器中状态转移网格的给定状态的累积转移概率进行阈值归一化。 阈值归一化可以通过比较和设置存储的转移概率中的单个比特来实现。 如果阈值为 2 b，则可以通过比较存储的转移概率的b 位来实现阈值比较。 当所有转移概率在网格的阶段超过阈值时，转换概率被缩放，例如通过减去阈值。 可以通过将存储之前将比较的b 位设置为零来实现缩放。 一般来说，由于累积的转移概率对于沿正向和反向方向通过网格的路径的转移概率单调增加，所以本发明可用于正向（α）和反向（β）转移概率两者的阈值归一化。

公开(公告)号：US20140233684A1

公开(公告)日：2014-08-21

申请号：US13769250

申请日：2013-02-15

Applicant: Xiao-an Wang

Inventor： Xiao-an Wang

IPC: H04L25/02

CPC classification number: H04L25/0204

Abstract: Most wireless channels are sparse, so sparse channel-based methods can be used for channel estimation and feedback with much better estimation accuracy and much lower feedback overhead. However, certain wireless channels can be non-sparse, for which sparse channel-based methods may cause degraded estimation quality and increased feedback overhead. Means of detecting the channel sparseness are described that provide simple and effective channel sparseness indicators and safeguard against the mismatch between non-sparse channels and sparse channel-based methods. Various fallback options can be used under non-sparse channels such that estimation degradation and feedback overhead are both minimized. Fake multipath removal in continuous time-domain parameter extraction, a sparse channel-based method, is also described that further improves estimation quality and reduces feedback overhead.

Abstract translation: 大多数无线信道是稀疏的，因此基于信道的稀疏方法可以用于信道估计和反馈，具有更好的估计精度和更低的反馈开销。 然而，某些无线信道可以是非稀疏的，对于这些信道，基于信道的稀疏方法可能导致估计质量下降和增加的反馈开销。 描述了检测通道稀疏度的手段，其提供简单有效的信道稀疏指示符，并且防止非稀疏信道与基于信道的稀疏信道之间的不匹配。 可以在非稀疏信道下使用各种备用选项，从而将估计降级和反馈开销都最小化。 还描述了连续时域参数提取中的虚拟多径去除，这是一种基于稀疏信道的方法，可进一步提高估计质量并降低反馈开销。

公开(公告)号：US20130242841A1

公开(公告)日：2013-09-19

申请号：US13419592

申请日：2012-03-14

Applicant: Xiao-an Wang

Inventor： Xiao-an Wang

IPC: H04W72/00

CPC classification number: H04W72/005 ,  H04L5/00 ,  H04L5/0023 ,  H04L5/0035 ,  H04L5/0048 ,  H04L25/022 ,  H04L25/0224

Abstract: Methods and apparatus of channel feedback are disclosed. In OFDM systems, the channel is acquired in the frequency domain. A generic multipath model for wireless channels, however, reveals that the time-domain parameters of the channel require much smaller data than the frequency-domain representation of the channel. Means to extracting the time-domain parameters from the frequency-domain channel samples are described for both the continuous time domain and the discrete time domain. Refinements of the time-domain parameters via minimizing a frequency-domain matching error are also described, which further improve the quality of the channel feedback and reduce the feedback overhead. Channel feedback with the time-domain parameters requires only a small fraction of the feedback overhead that is needed by existing channel feedback schemes, and maintains consistently superior performances over wireless channels of various delay spreads, short or long.

Abstract translation: 公开了信道反馈的方法和装置。 在OFDM系统中，在频域中获取信道。 然而，用于无线信道的通用多径模型揭示了信道的时域参数需要比信道的频域表示少得多的数据。 对于连续时域和离散时域都描述了从频域信道样本中提取时域参数的手段。 还描述了通过最小化频域匹配误差来改进时域参数，这进一步提高了信道反馈的质量并减少了反馈开销。 具有时域参数的信道反馈仅需要现有信道反馈方案所需的反馈开销的一小部分，并且在短时间或长的各种延迟传播的无线信道上保持一致的优异性能。