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    • 32. 发明申请
    • METHODS AND SYSTEMS FOR TIMING ACQUISITION ROBUST TO CHANNEL FADING
    • 用于定时采集的方法和系统对信道渐弱的鲁棒性
    • US20100246564A1
    • 2010-09-30
    • US12644856
    • 2009-12-22
    • Bojan VrceljKrishna K. MukkavilliRaghuraman KrishnamoorthiAshok Mantravadi
    • Bojan VrceljKrishna K. MukkavilliRaghuraman KrishnamoorthiAshok Mantravadi
    • H04J3/06H04L27/28
    • H04L27/2662H04L25/0212H04L25/0216H04L27/2695
    • The embodiments provide mechanisms for synchronizing a receiver with OFDM pilots that are robust in the presence of channel fading conditions. In addition to using instantaneous channel estimate values to locate the first arriving path and last arriving path, the methods calculate time-domain averaged channel estimate values and use those averaged values to determine an average first arriving path and last arriving path. A combination of the instantaneous first arriving path and last arriving path and the average first arriving path and last arriving path may then be used to determine the delay spread and calculate a timing offset to be applied in timing synchronization. The various embodiments introduce improvements under channel fading conditions. Time-domain averaging may be embodied in a flexible DSP processor, or implemented in hardware and/or software. Using both instantaneous and time-averaged channel estimates greatly improves the robustness of time synchronization under channel fading conditions.
    • 实施例提供了用于使接收机与存在信道衰落条件时鲁棒的OFDM导频同步的机制。 除了使用瞬时信道估计值来定位第一到达路径和最后到达路径之外,该方法还计算时域平均信道估计值,并使用这些平均值来确定平均第一到达路径和最后到达路径。 然后可以使用瞬时第一到达路径和最后到达路径以及平均第一到达路径和最后到达路径的组合来确定延迟扩展,并计算要在定时同步中应用的定时偏移。 各种实施例在信道衰落条件下引入改进。 时域平均可以体现在灵活的DSP处理器中,或者在硬件和/或软件中实现。 使用瞬时和时间平均信道估计大大提高了信道衰落条件下时间同步的鲁棒性。
    • 38. 发明申请
    • Collection window positioning using time tracking information
    • 收集窗口定位使用时间跟踪信息
    • US20060245349A1
    • 2006-11-02
    • US11371837
    • 2006-03-08
    • Bojan VrceljAshok MantravadiFuyun LingRajiv VijayanMichael Wang
    • Bojan VrceljAshok MantravadiFuyun LingRajiv VijayanMichael Wang
    • H04J11/00
    • H04L27/2662H04L5/0007H04L5/0048H04L25/0216H04L25/022H04L25/0228H04L27/261H04L27/265H04L27/2665H04L27/2679
    • A method for positioning a collection window for a Fourier transform function is disclosed. A first orthogonal frequency division multiplexing (OFDM) symbol and a second OFDM symbol are received. The first OFDM symbol comprises a plurality of frequency division multiplexed (FDM) symbols. The first OFDM symbol is characterized by at least two of the following: a delay spread, a first arriving path (FAP), or a last arriving path (LAP). A channel location is estimated from a channel impulse response. A point relative to the channel location is selected. A beginning of the collection window is positioned for the second OFDM symbol at the selected point. Alternatively, a point is selected at a first location relative to the channel location using a first algorithm if a delay spread is less than a predetermined length. The selected point is chosen at a second location relative to the channel location using a second algorithm if the delay spread is greater than the predetermined length.
    • 公开了一种用于定位用于傅立叶变换函数的收集窗口的方法。 接收第一正交频分复用(OFDM)符号和第二OFDM符号。 第一OFDM符号包括多个频分复用(FDM)符号。 第一OFDM符号的特征在于以下至少两个:延迟扩展,第一到达路径(FAP)或最后到达路径(LAP)。 从信道脉冲响应估计信道位置。 选择相对于通道位置的点。 收集窗口的开始位于所选点处的第二OFDM符号。 或者,如果延迟扩展小于预定长度,则使用第一算法在相对于信道位置的第一位置处选择点。 如果延迟扩展大于预定长度,则使用第二算法在相对于信道位置的第二位置处选择所选择的点。