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    • 7. 发明授权
    • Frame synchronization and detection technique for a digital receiver
    • 数字接收机的帧同步和检测技术
    • US06850582B2
    • 2005-02-01
    • US10392115
    • 2003-03-17
    • Deirdre O'SheaIsmail LakkisSaeid SafaviMasood K. TayebiBaya HatimCathal O'Scolai
    • Deirdre O'SheaIsmail LakkisSaeid SafaviMasood K. TayebiBaya HatimCathal O'Scolai
    • H04J13/00H04W84/14H04L7/00
    • H04W84/14
    • A system and method of frame synchronization and detection for use in a digital receiver within a communication system. The digital radio communication system includes a receiver for receiving a signal stream that includes data frames. Each frame includes an arbitrary data sequence and a unique word. A predetermined number of contiguous bits from the unique word are appended to the beginning of each data frame to identify the start of the data frame. The communication system comprises a sampling circuit for sampling symbol levels, a filter to implement the cross correlation of the received signal with the stored unique word, a threshold detector circuit to detect when frame synchronization is achieved as well as additional circuitry to refine the estimate from the threshold detection circuit. The design utilizes coherent demodulation. However, the design is equally applicable to non-coherent demodulation. In one embodiment, the sampling rate is assumed to be two samples per symbol. However, the functionality of the proposed design is not limited to two samples per symbol.
    • 用于通信系统内的数字接收机中的帧同步和检测的系统和方法。 数字无线电通信系统包括用于接收包括数据帧的信号流的接收机。 每帧包括任意数据序列和唯一字。 来自唯一字的预定数量的连续位被附加到每个数据帧的开头,以标识数据帧的开始。 通信系统包括用于对符号电平进行采样的采样电路,用于实现接收信号与存储的唯一字的互相关的滤波器,用于检测何时实现帧同步的阈值检测器电路以及用于从 阈值检测电路。 该设计采用相干解调。 然而,该设计同样适用于非相干解调。 在一个实施例中,假设采样率是每个符号的两个样本。 然而,所提出的设计的功能不限于每个符号两个样本。
    • 10. 发明授权
    • Non-data-aided maximum likelihood based feedforward timing synchronization method
    • 非数据辅助最大似然估计前馈时序同步方法
    • US06359878B1
    • 2002-03-19
    • US09119327
    • 1998-07-20
    • Ismail LakkisDeirdre O'SheaMasood K. TayebiBaya Hatim
    • Ismail LakkisDeirdre O'SheaMasood K. TayebiBaya Hatim
    • H04J306
    • H04W84/14H04L7/0029H04L7/027
    • A system and method of timing estimation for use in a digital receiver within a communication system. A timing estimation block is provided within a digital receiver, where the input signal is processed at four or more samples per symbol and the estimation block operates in a feedforward manner. The algorithm calculates the timing offset by evaluating the spectral component at the symbol clock frequency. The spectral component is generated using a nonlinearity operation. However, the maximum likelihood non-data-aided timing estimation equation reveals an alternative approximation for the logarithm of the hyperbolic cosine function present in the maximum likelihood equation, which offers an excellent compromise between implementation complexity and variance performance. The estimated timing offset is then fed to a timing correction unit, which calculates the data samples corresponding to the sampling clock phase and removes the redundant samples. The ideal sampled signal is then forwarded to additional synchronization and functional units for further processing. This method is provided for a variety of digital receivers employing Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA) and or any combination of the principles of the above or other technologies. In accordance with one embodiment of the invention, a digital receiver system comprises an anti-aliasing filter, a sampling unit, a filtering block, a timing estimation block, a timing correction block and additional synchronization and functional units block.
    • 用于在通信系统内的数字接收机中使用的定时估计的系统和方法。 在数字接收机内提供定时估计块,其中输入信号以每符号四个或更多个采样进行处理,并且估计块以前馈方式操作。 该算法通过评估符号时钟频率处的频谱分量来计算定时偏移。 使用非线性运算产生频谱分量。 然而,最大似然非数据辅助定时估计方程揭示了最大似然方程中存在的双曲余弦函数的对数的替代近似,这在实现复杂度和方差性能之间提供了极好的折中。 然后将估计的定时偏移馈送到定时校正单元,该定时校正单元计算对应于采样时钟相位的数据采样并且去除冗余采样。 然后将理想采样信号转发到附加的同步和功能单元进行进一步处理。 该方法被提供用于采用码分多址(CDMA),时分多址(TDMA),频分多址(FDMA)以及上述或其他技术的原理的任何组合的各种数字接收机。 根据本发明的一个实施例,数字接收机系统包括抗混叠滤波器,采样单元,滤波块,定时估计块,定时校正块和附加同步以及功能单元块。