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21. 发明授权

US09106497B2 Apparatus and method for improving OFDM receiver performance in the presence of narrowband interferers 有权
标题翻译：在存在窄带干扰的情况下改善OFDM接收机性能的装置和方法
公开(公告)号：US09106497B2
公开(公告)日：2015-08-11
申请号：US13596993
申请日：2012-08-28
申请人： Bernard Arambepola , Thushara Hewavithana
发明人： Bernard Arambepola , Thushara Hewavithana
IPC分类号： H04L25/08 , H04L1/00 , H04B1/10 , H04L27/26 , H03K6/04 , H03K5/01 , H03D1/06 , H03D1/04
CPC分类号： H04L27/265 , H04L27/2657 , H04L27/2688 , H04L27/2691
摘要： In an Orthogonal Frequency Division Multiplex (“OFDM”) system, the problem of an interferer reducing the signal-to-noise ratio of a signal can be mitigated by generating an interferer-correction signal and subtracting it from the signal to be processed. The amplitude, frequency and phase of the interferences are determined first. The frequency is estimated by averaging the squared-magnitude of multiple FFTs of the incoming signal and then locating the spectral peaks. The phase and amplitude may be estimated from this FFT outputs or through a process of correlation in the time domain. The interferer-correction signal is generated from the estimated amplitude, frequency, and phase. The correction to be subtracted from the main signal in order to reduce the effect of the interference may be generated in the time or frequency domain. The subtraction of the correction may also be implemented in the time or frequency domains.
摘要翻译：在正交频分复用（“OFDM”）系统中，可以通过产生干扰校正信号并从要处理的信号中减去干扰源来减少信号的信噪比的问题。首先确定干扰的幅度，频率和相位。通过对输入信号的多个FFT的平方幅度进行平均，然后定位频谱峰值来估计频率。可以从该FFT输出或通过时域中的相关过程来估计相位和幅度。从估计的幅度，频率和相位产生干扰校正信号。可以在时域或频域中产生要从主信号中减去以减少干扰的影响的校正。校正的减法也可以在时域或频域中实现。

22. 发明授权

US08938015B2 Orthogonal frequency division multiplex (OFDM) demodulator with improved cyclic ambiguity resolution 有权
标题翻译：具有改进的循环模糊度分辨率的正交频分复用（OFDM）解调器
公开(公告)号：US08938015B2
公开(公告)日：2015-01-20
申请号：US13997706
申请日：2012-03-15
申请人： Bernard Arambepola , Thushara Hewavithana
发明人： Bernard Arambepola , Thushara Hewavithana
IPC分类号： H04L27/22 , H04L27/01 , H04B17/00 , H04L27/26
CPC分类号： H04L27/22 , H04L25/03159 , H04L27/01 , H04L27/26 , H04L27/2665 , H04L27/2672 , H04L27/2675 , H04L27/2679 , H04L27/2695
摘要： A system according to one embodiment includes a demodulator configured to receive an OFDM modulated signal over a channel, the signal including a sequence of symbols, each of the symbols including one or more pilot carriers and one or more data carriers; a time filtering and interpolation circuit coupled to the demodulator, the time filtering and interpolation circuit configured to estimate the frequency response of the channel based on time filtering and interpolation of the pilot carriers; a phase slope correction circuit configured to apply each of a plurality of phase slope corrections to the frequency response and to the data carriers; a frequency filtering and interpolation circuit configured to calculate frequency response estimates of the channel at data carrier frequencies based on frequency filtering and interpolation of the phase slope corrected frequency response; an equalization circuit configured to equalize the phase slope corrected data carriers based on the calculated frequency response estimates; an error calculation circuit configure to calculate the mean square error between the equalized data carriers and a nearest QAM constellation point; and an iterative phase slope optimization circuit configured to select the phase slope correction associated with the minimum of the mean square errors, wherein the selected phase slope resolves the cyclic ambiguity.
摘要翻译：根据一个实施例的系统包括：解调器，被配置为通过信道接收OFDM调制信号，所述信号包括符号序列，每个符号包括一个或多个导频载波和一个或多个数据载波; 耦合到解调器的时间滤波和内插电路，所述时间滤波和内插电路被配置为基于导频载波的时间滤波和内插来估计信道的频率响应; 相位斜率校正电路，被配置为对频率响应和数据载波施加多个相位斜率校正中的每一个; 频率滤波和内插电路，被配置为基于频率滤波和相位斜率校正频率响应的内插来计算数据载波频率处的信道的频率响应估计; 均衡电路，被配置为基于所计算的频率响应估计来均衡相位斜率校正数据载波; 误差计算电路，用于计算均衡数据载波与最近的QAM星座点之间的均方误差; 以及迭代相位斜率优化电路，被配置为选择与所述均方误差的最小值相关联的相位斜率校正，其中所选择的相位斜率解决所述循环模糊度。

23. 发明授权

US08897412B2 Method and apparatus for phase noise mitigation 有权
标题翻译：减噪相位噪声的方法和装置
公开(公告)号：US08897412B2
公开(公告)日：2014-11-25
申请号：US13714530
申请日：2012-12-14
申请人： Thushara Hewavithana , Bernard Arambepola
发明人： Thushara Hewavithana , Bernard Arambepola
IPC分类号： H04B1/10 , H04L27/01 , H04L27/26
CPC分类号： H04L27/01 , H04L27/2647 , H04L27/3836 , H04L2027/0038 , H04L2027/0087
摘要： An approach is provided to mitigate phase noise by correcting common phase error and inter-carrier-interference in a received signal. The approach involves determining a received signal includes phase noise comprising at least a common phase error component and an inter-carrier-interference component. The approach also involves causing the common phase error to be corrected based on one or more pilot carriers. The approach further involves causing an estimate of a main signal component to be subtracted from the one or more pilot carriers. The approach additionally involves determining a sequence of estimated coefficients of a multiplicative phase noise sequence. The approach also involves causing the inter-carrier-inference to be corrected by processing the multiplicative phase noise sequence using the sequence of estimated coefficients. The approach further involves causing an equalized data signal to be output based on the corrected common phase error and the corrected inter-carrier-interference.
摘要翻译：提供了一种通过校正接收信号中的公共相位误差和载波间干扰来减轻相位噪声的方法。该方法包括确定接收信号包括至少包括公共相位误差分量和载波间干扰分量的相位噪声。该方法还涉及基于一个或多个导频载波来校正公共相位误差。该方法还包括导致从一个或多个导频载波减去主信号分量的估计。该方法还涉及确定乘法相位噪声序列的估计系数序列。该方法还涉及通过使用估计系数的序列处理乘法相位噪声序列来使得载波间推理被校正。该方法进一步包括使得基于校正的公共相位误差和校正的载波间干扰来输出均衡的数据信号。

24. 发明授权

US08582035B2 Apparatus, systems and methods utilizing adjacent-channel power dependent automatic gain control for digital television demodulation 有权
标题翻译：利用用于数字电视解调的相邻信道功率依赖的自动增益控制的装置，系统和方法
公开(公告)号：US08582035B2
公开(公告)日：2013-11-12
申请号：US13032079
申请日：2011-02-22
申请人： Parveen K Shukla , Bernard Arambepola , Thushara Hewavithana , Sahan S Gamage
发明人： Parveen K Shukla , Bernard Arambepola , Thushara Hewavithana , Sahan S Gamage
IPC分类号： H04N5/52
CPC分类号： H04N5/455 , H04N5/52 , H04N21/4382 , H04N21/6112
摘要： An embodiment of the present invention provides a method for digital television demodulation, comprising using adjacent-channel power dependent automatic gain control (AGC) for the digital television demodulation, wherein an AGC technique takes into account a total power as well as power of adjacent channels to control gain of a gain control amplifier.
摘要翻译：本发明的一个实施例提供一种用于数字电视解调的方法，包括对数字电视解调使用相邻信道功率依赖自动增益控制（AGC），其中AGC技术考虑到相邻信道的总功率和功率以控制增益控制放大器的增益。

25. 发明授权

US08457256B2 Channel-adaptive likelihood determination 失效
标题翻译：通道自适应似然确定
公开(公告)号：US08457256B2
公开(公告)日：2013-06-04
申请号：US12862951
申请日：2010-08-25
申请人： Sahan S. Gamage , Bernard Arambepola , Thushara Hewavithana , Parveen K. Shukla , Vinesh Bhunjun
发明人： Sahan S. Gamage , Bernard Arambepola , Thushara Hewavithana , Parveen K. Shukla , Vinesh Bhunjun
IPC分类号： H03D1/00
CPC分类号： H04L25/067
摘要： Methods and systems to compute likelihood measures of demodulated, complex-coordinate data points, to and dynamically scale the likelihood measures as a function of a channel statistic, and to decode the data points from the scaled likelihood measures. Likelihood measures may be computed relative to all points, or a subset of points of a reference constellation, such as a subset of one or more nearest constellation points. Likelihood measures may be scaled as a function of a channel frequency response variance amongst a plurality of carriers, such as carriers of an OFDM signal, and/or as a function of a channel impulse response variance.
摘要翻译：用于计算解调的复坐标数据点的似然度量的方法和系统，并将似然度量动态地缩放为通道统计量的函数，并且从经比例缩放的似然度量来解码数据点。可以相对于所有点或参考星座的点的子集（诸如一个或多个最近星座点的子集）计算似然度量。似然度量可以被缩放为多个载波之类的信道频率响应方差的函数，诸如OFDM信号的载波，和/或作为信道脉冲响应方差的函数。

26. 发明授权

US08396144B2 Method and system for OFDM symbol timing recovery 有权
标题翻译：用于OFDM符号定时恢复的方法和系统
公开(公告)号：US08396144B2
公开(公告)日：2013-03-12
申请号：US12347598
申请日：2008-12-31
申请人： Bernard Arambepola , Parveen K. Shukla , Thushara Hewavithana
发明人： Bernard Arambepola , Parveen K. Shukla , Thushara Hewavithana
IPC分类号： H04J11/00 , H04L27/28
CPC分类号： H04L27/2691 , H04L25/0212 , H04L25/03057 , H04L27/2665 , H04L27/2695
摘要： A method and system for OFDM symbol timing recovery is described. A symbol timing recovery module of an OFDM receiver is configured to determine an optimum trigger point for performing a discrete Fourier transform in a manner that minimizes inter-symbol interference.
摘要翻译：描述了用于OFDM符号定时恢复的方法和系统。 OFDM接收机的符号定时恢复模块被配置为以使符号间干扰最小化的方式确定用于执行离散傅里叶变换的最佳触发点。

27. 发明授权

US08392802B2 Spectral content based decoding and frequency offset estimation 有权
标题翻译：基于频谱内容的解码和频偏估计
公开(公告)号：US08392802B2
公开(公告)日：2013-03-05
申请号：US12646680
申请日：2009-12-23
申请人： Bernard Arambepola , Vinesh Bhunjun , Thushara Hewavithana , Parveen K. Shukla , Sahan Gamage
发明人： Bernard Arambepola , Vinesh Bhunjun , Thushara Hewavithana , Parveen K. Shukla , Sahan Gamage
IPC分类号： G06F11/00
CPC分类号： H04L1/0045 , H03M13/1102 , H04L1/0039 , H04L1/0072 , H04L27/0014 , H04L2027/003 , H04L2027/0095
摘要： Methods and systems to identify a codeword associated with samples of a signal from spectral content of the samples, and to estimate a frequency offset from the spectral contents. The samples may correspond to a physical layer header of a data frame. Modulation may be removed from the samples in accordance with each of a plurality of modulation sequences, each sequence associated with a corresponding codeword. Power levels in spectral contents of the modulation-removed samples are examined to identify a peak power level indicative of a match between a modulation sequence and the samples. The corresponding codeword is identified as being associated with the header, and transmission parameters associated with the identified codeword are used to decode a corresponding frame. An estimated frequency offset may be determined from a frequency associated with the peak power level.
摘要翻译：用于识别与样本的频谱内容的信号的样本相关联的码字的方法和系统，以及估计与频谱内容的频率偏移。样本可以对应于数据帧的物理层报头。可以根据多个调制序列中的每一个从样本中去除调制，每个序列与相应的码字相关联。检查调制去除的样本的频谱内容中的功率电平以识别指示调制序列与样本之间的匹配的峰值功率电平。相应的码字被识别为与报头相关联，并且与所识别的码字相关联的传输参数被用于对相应的帧进行解码。可以从与峰值功率电平相关联的频率确定估计的频率偏移。

28. 发明授权

US08340222B2 Parameter and scattered pilot based symbol timing recovery 有权
标题翻译：基于参数和散射导频的符号定时恢复
公开(公告)号：US08340222B2
公开(公告)日：2012-12-25
申请号：US12647060
申请日：2009-12-24
申请人： Bernard Arambepola , Thushara Hewavithana , Praveen K. Shukla
发明人： Bernard Arambepola , Thushara Hewavithana , Praveen K. Shukla
IPC分类号： H04L27/00 , H04J11/00
CPC分类号： H04L25/0224 , H04L25/0204 , H04L25/0212 , H04L25/022 , H04L27/2665 , H04L27/2675 , H04L27/2695
摘要： Methods and systems to resolve the cyclic time ambiguity of a scattered pilot based channel impulse response, including to determine a channel impulse response from a combination of scattered pilots and encoded parameters, such as L1-pre signaling within P2 symbols of a terrestrial digital video broadcast (DVD) in a single frequency network (SFN), and including to re-use a corresponding window time to track the channel impulse response in the absence of encoded parameters. Methods and systems disclosed herein may be implemented with respect to channel acquisition and tracking, including adjusting a Fast Fourier Transform trigger point to reduce inter-symbol interference.
摘要翻译：解决基于分散导频的信道脉冲响应的循环时间模糊度的方法和系统，包括从散射导频和编码参数的组合确定信道脉冲响应，例如地面数字视频广播的P2符号内的L1预信令（DVD），并且包括在没有编码参数的情况下重新使用相应的窗口时间来跟踪信道脉冲响应。本文公开的方法和系统可以相对于信道获取和跟踪来实现，包括调整快速傅里叶变换触发点以减少符号间干扰。

29. 发明授权

US08237870B2 Receiver system for multiple bandwidth television channels 有权
标题翻译：接收机系统，用于多个带宽电视频道
公开(公告)号：US08237870B2
公开(公告)日：2012-08-07
申请号：US11863748
申请日：2007-09-28
申请人： Parveen K Shukla , Bernard Arambepola , Thushara Hewavithana
发明人： Parveen K Shukla , Bernard Arambepola , Thushara Hewavithana
IPC分类号： H04L27/06 , H04L27/08 , H04B1/16 , H04B1/26 , H04B15/00 , H04N7/12 , H04N11/02 , H04N11/04 , H04N5/00 , H04N9/64 , H04N5/44 , H04N5/455 , H04N5/50 , H04N5/46
CPC分类号： H04N5/4446 , H04N5/52
摘要： Disclosed is a receiver system, capable of receiving RF signals on television channels of multiple bandwidths. The receiver system includes a tuner, an analog IF filter, an ADC, a mixer module, one or more digital filters, an AGC module and a controller. The tuner converts an RF signal into an IF signal using a mixer frequency. The analog IF filter filters out a fixed band signal from the IF signal. The ADC module converts the fixed band signal into a digital signal, which is filtered by digital filters. The output of the digital filters is converted to a base band signal and the power level of the base band signal is controlled by the AGC module. The controller selects a mixer frequency from a group of mixer frequencies based on a function of power of the output of the AGC module by applying each mixer frequency to the tuner.
摘要翻译：公开了一种能够在多个带宽的电视频道上接收RF信号的接收机系统。接收机系统包括调谐器，模拟IF滤波器，ADC，混频器模块，一个或多个数字滤波器，AGC模块和控制器。调谐器使用混频器将RF信号转换成IF信号。模拟IF滤波器滤除来自IF信号的固定频带信号。 ADC模块将固定频带信号转换为数字信号，由数字滤波器滤波。数字滤波器的输出转换为基带信号，基带信号的功率电平由AGC模块控制。控制器通过将每个混频器频率应用于调谐器，基于AGC模块的输出功率的函数，从一组混频器中选择混频器频率。

30. 发明授权

US08204156B2 Phase error detection with conditional probabilities 有权
标题翻译：具有条件概率的相位误差检测
公开(公告)号：US08204156B2
公开(公告)日：2012-06-19
申请号：US12317970
申请日：2008-12-31
申请人： Thushara Hewavithana , Bernard Arambepola , Parveen K. Shukla , Sahan S. Gamage , Vinesh Bhunjun
发明人： Thushara Hewavithana , Bernard Arambepola , Parveen K. Shukla , Sahan S. Gamage , Vinesh Bhunjun
IPC分类号： H04L27/00 , H03D3/22
CPC分类号： H04L27/3827 , H04L27/2273 , H04L2027/003 , H04L2027/0036 , H04L2027/0038 , H04L2027/0057 , H04L2027/0067 , H04L2027/0069
摘要： Apparatuses, systems, and methods that employ conditional probabilities to calculate phase errors are disclosed. For a received signal, the embodiments may develop several phase error estimates relative to each point of a constellation, the number and location of points of the constellation depending on the modulation technique of the received signal. In addition to calculating the phase error estimates, the embodiments may also calculate weights, or probabilities, associated with each of the estimates. The embodiments may use the estimates and the weights to calculate a composite phase error estimate. The composite phase error estimate may be used to correct the received signal and eliminate or reduce the impact of the phase error.
摘要翻译：公开了使用条件概率来计算相位误差的装置，系统和方法。对于接收到的信号，实施例可以根据接收信号的调制技术，相对于星座的每个点，星座的点的数量和位置来形成几个相位误差估计。除了计算相位误差估计之外，实施例还可以计算与每个估计相关联的权重或概率。实施例可以使用估计和权重来计算复合相位误差估计。复合相位误差估计可以用于校正接收到的信号，并消除或减少相位误差的影响。

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