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    Method and apparatus of low-complexity pattern dependent lookup table pre-compensation
    1.
    发明授权
    Method and apparatus of low-complexity pattern dependent lookup table pre-compensation 有权

    公开(公告)号：US11451329B2

    公开(公告)日：2022-09-20

    申请号：US17157691

    申请日：2021-01-25

    申请人： Jianhong Ke ,  Chuandong Li ,  Xuefeng Tang

    发明人： Jianhong Ke ,  Chuandong Li ,  Xuefeng Tang

    IPC分类号： H04L1/00

    摘要： Methods and systems for performing signal pre-correction of a transmission signal comprising a sequence of symbols using a Pattern Dependent Look-up Table (PDLUT) containing one or more distortion correction values. Upon accessing a distortion correction value from the PDLUT for a symbol of the sequence of symbols, the accessed distortion correction value is quantized into one or more quantized values according to one or more quantizations, thereby reducing the bit-width of the distortion correction value. The transmission signal and the distortion correction value with reduced bit-width may undergo linear correction compensation, such as through a finite impulse response (FIR) filter, independent of one another, where the one or more quantized correction values with reduced bit-width reduce a number of calculation steps performed during linear correction compensation resulting in power savings. The linearly compensated quantized values and the linearly compensated signal are combined to form a pre-corrected signal.

    METHOD AND APPARATUS OF LOW-COMPLEXITY PATTERN DEPENDENT LOOKUP TABLE PRE-COMPENSATION
    2.
    发明申请
    METHOD AND APPARATUS OF LOW-COMPLEXITY PATTERN DEPENDENT LOOKUP TABLE PRE-COMPENSATION 有权

    公开(公告)号：US20220239407A1

    公开(公告)日：2022-07-28

    申请号：US17157691

    申请日：2021-01-25

    申请人： Jianhong KE ,  Chuandong LI ,  Xuefeng TANG

    发明人： Jianhong KE ,  Chuandong LI ,  Xuefeng TANG

    IPC分类号： H04L1/00

    摘要： Methods and systems for performing signal pre-correction of a transmission signal comprising a sequence of symbols using a Pattern Dependent Look-up Table (PDLUT) containing one or more distortion correction values. Upon accessing a distortion correction value from the PDLUT for a symbol of the sequence of symbols, the accessed distortion correction value is quantized into one or more quantized values according to one or more quantizations, thereby reducing the bit-width of the distortion correction value. The transmission signal and the distortion correction value with reduced bit-width may undergo linear correction compensation, such as through a finite impulse response (FIR) filter, independent of one another, where the one or more quantized correction values with reduced bit-width reduce a number of calculation steps performed during linear correction compensation resulting in power savings. The linearly compensated quantized values and the linearly compensated signal are combined to form a pre-corrected signal.

    Method and apparatus for frequency domain equalization with low complexity and loop delay
    3.
    发明授权
    Method and apparatus for frequency domain equalization with low complexity and loop delay 有权

    公开(公告)号：US11108599B1

    公开(公告)日：2021-08-31

    申请号：US16936098

    申请日：2020-07-22

    申请人： Chuandong Li ,  Jianhong Ke

    发明人： Chuandong Li ,  Jianhong Ke

    IPC分类号： H04L25/03 ,  H04B10/61

    摘要： Methods and devices are described for frequency domain equalization with low complexity and loop delay. A transmitter inserts pilot symbols into a data signal at intervals of every n data bits. These pilot symbols are used by a receiver-side frequency-domain equalizer to calculate error levels and equalize the received data signal to effect impairment compensation such as SOP tracking. QPSK or BPSK symbols may be used for the pilot symbols, simplifying error calculation into an addition operation instead of the conventional multiplication operation required by conventional FDEQs. Equalizers are described that may operate in a pilot-assisted mode, a conventional decision-directed mode, or both.

    PARTIALLY DISJOINT EQUALIZATION AND CARRIER RECOVERY
    5.
    发明申请
    PARTIALLY DISJOINT EQUALIZATION AND CARRIER RECOVERY 审中-公开

    公开(公告)号：US20190182082A1

    公开(公告)日：2019-06-13

    申请号：US15838499

    申请日：2017-12-12

    申请人： Nash'at Abughalieh ,  Syed Faisal Ali Shah ,  Chuandong Li

    发明人： Nash'at Abughalieh ,  Syed Faisal Ali Shah ,  Chuandong Li

    IPC分类号： H04L25/03 ,  H04B10/61

    摘要： An apparatus in a signal receiver, such as an optical signal receiver, is provided. An adaptive equalizer provides an equalized output indicative of a received signal. A feedback component receives the equalized output and provides feedback to the adaptive equalizer. A carrier recovery component receives the equalized output from the adaptive equalizer provides estimates of symbols. The carrier recovery component is partially or fully disjoint from the feedback component, thus removing the carrier recovery component from equalizer the feedback loop. The feedback component can include an initial carrier recovery component and a phase rotation and detection component. The initial carrier recovery component generates a carrier recovery output based on the equalized output. The phase rotation and detection component performs a phase rotation based on the carrier recovery output.

    Fractionally spaced adaptive equalizer with non-integer sampling
    8.
    发明授权
    Fractionally spaced adaptive equalizer with non-integer sampling 有权

    公开(公告)号：US09755864B1

    公开(公告)日：2017-09-05

    申请号：US15228592

    申请日：2016-08-04

    申请人： Syed Faisal Ali Shah ,  Chuandong Li ,  Zhuhong Zhang

    发明人： Syed Faisal Ali Shah ,  Chuandong Li ,  Zhuhong Zhang

    IPC分类号： H04L25/03

    CPC分类号： H04L25/03949 ,  H04L25/03063 ,  H04L25/03885

    摘要： An apparatus for performing fractionally spaced adaptive equalization with non-integer sub-symbol sampling has an adaptive equalizer that receives a continuous stream of input data having a non-integer, fractional delay between consecutive samples at a non-integer, sub-symbol rate and outputs a stream of equalized data based on tap weights of taps of the adaptive equalizer that are spaced at an interval corresponding to the non-integer, sub-symbol rate. The tap weights are updated independently of the fractional delay between consecutive samples of the input data using an error signal. An equalizer output alignment component downstream of the adaptive equalizer aligns the stream of equalized data with a corresponding transmitted symbol.

    Optical communications system having chromatic dispersion and polarization mode dispersion compensation
    10.
    发明授权
    Optical communications system having chromatic dispersion and polarization mode dispersion compensation 有权
    具有色散和偏振模色散补偿的光通信系统

    公开(公告)号：US09520950B2

    公开(公告)日：2016-12-13

    申请号：US12330691

    申请日：2008-12-09

    申请人： James Harley ,  Kim Roberts ,  Chuandong Li

    发明人： James Harley ,  Kim Roberts ,  Chuandong Li

    IPC分类号： H04B10/00 ,  H04B10/532 ,  H04B10/2513 ,  H04B10/69

    CPC分类号： H04B10/532 ,  H04B10/25137 ,  H04B10/6972 ,  H04B2210/252 ,  H04B2210/254

    摘要： Described are an optical communications system and a method that allow for compensation of chromatic dispersion and polarization mode dispersion imparted to a communications signal propagating through an optical link. The system is based on a cost-effective optical transport architecture that accommodates baud rates exceeding 15 Gbaud and eliminates the need for costly optical dispersion compensators. Compensation for polarization mode dispersion is performed at the receiver using nonlinear processing. Advantageously, direct detection modulation using inexpensive electro-optic system components can be used in place of more costly and complex coherent and differential modulation formats. Digital filtering can be performed at the transmitter and the input signal can be inverted based on the nonlinearity of the transmitter electro-optic components. Consequently, the bandwidth and linearity requirements for the transmitter electro-optic components are relaxed, and cost reductions are realized.

    摘要翻译： 描述了允许补偿通过光链路传播的通信信号的色散和偏振模色散的光通信系统和方法。 该系统基于具有成本效益的光学传输架构，其适应波特率超过15Gbaud，并且不需要昂贵的光学色散补偿器。 使用非线性处理在接收机处执行偏振模色散的补偿。 有利地，可以使用廉价的电光系统组件的直接检测调制来代替更昂贵和复杂的相干和差分调制格式。 可以在发射机处执行数字滤波，并且可以基于发射机电光部件的非线性来反转输入信号。 因此，放大了发射机电光元件的带宽和线性要求，并实现成本降低。