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公开(公告)号：US20190182082A1
公开(公告)日：2019-06-13
申请号：US15838499
申请日：2017-12-12
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.
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公开(公告)号：US09755864B1
公开(公告)日：2017-09-05
申请号：US15228592
申请日：2016-08-04
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.
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公开(公告)号：US20170257234A1
公开(公告)日：2017-09-07
申请号：US15228592
申请日：2016-08-04
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.
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公开(公告)号：US09871597B2
公开(公告)日：2018-01-16
申请号：US15095569
申请日：2016-04-11
IPC分类号： H04B10/61 , H04B10/079 , H04B10/25 , H04B10/60 , H04J14/02 , H04B10/2507
CPC分类号： H04B10/6164 , H04B10/07955 , H04B10/25 , H04B10/2507 , H04B10/60 , H04J14/0278
摘要： A method and apparatus is described for estimating a local oscillator frequency offset (LOFO) of a received optical signal in a coherent optical receiver. The method includes receiving a signal by the coherent optical receiver; digitally shifting a spectrum of the received signal according to one of a plurality of frequency shifts within a first range; equalizing each shifted signal based on a hybrid shifted filter response of a receiver driver, the hybrid shifted filter response is based on a combination of a linear shifted response and a circular shifted filter response of the receiver driver; calculating a difference of power between two sides of a spectrum of each equalized signal, the power for each side of the spectrum being calculated within a first area centered around a frequency corresponding to half of a baud rate of the received signal; determining a minimum power difference among the plurality of frequency shifts within the first range; and estimating the LOFO based on the minimum power difference.
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公开(公告)号：US20170294971A1
公开(公告)日：2017-10-12
申请号：US15095569
申请日：2016-04-11
IPC分类号： H04B10/61 , H04B10/079
CPC分类号： H04B10/6164 , H04B10/07955 , H04B10/25 , H04B10/2507 , H04B10/60 , H04J14/0278
摘要： A method and apparatus is described for estimating a local oscillator frequency offset (LOFO) of a received optical signal in a coherent optical receiver. The method includes receiving a signal by the coherent optical receiver; digitally shifting a spectrum of the received signal according to one of a plurality of frequency shifts within a first range; equalizing each shifted signal based on a hybrid shifted filter response of a receiver driver, the hybrid shifted filter response is based on a combination of a linear shifted response and a circular shifted filter response of the receiver driver; calculating a difference of power between two sides of a spectrum of each equalized signal, the power for each side of the spectrum being calculated within a first area centered around a frequency corresponding to half of a baud rate of the received signal; determining a minimum power difference among the plurality of frequency shifts within the first range; and estimating the LOFO based on the minimum power difference.
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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.
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7.发明授权公开(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
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.
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公开(公告)号：US11038598B1
公开(公告)日：2021-06-15
申请号：US16801608
申请日：2020-02-26
申请人： Jianhong Ke , Chuandong Li
发明人： Jianhong Ke , Chuandong Li
摘要： Aspects of the present application provide methods and devices for compensating crosstalk in in the digital domain, the crosstalk occurring in the analog domain, for an optical coherent transceiver on a photonic integrated circuit (PIC).
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公开(公告)号：US09929805B2
公开(公告)日：2018-03-27
申请号：US15151895
申请日：2016-05-11
申请人： Zhiping Jiang , Zhuhong Zhang , Chuandong Li
发明人： Zhiping Jiang , Zhuhong Zhang , Chuandong Li
IPC分类号： H04J14/02 , H04B10/11 , H04L5/00 , H04B1/00 , H04B10/556
CPC分类号： H04B10/11 , H04B1/0007 , H04B10/50 , H04B10/5563 , H04B2210/075 , H04J14/02 , H04J14/0276 , H04L5/0048 , H04L25/0226
摘要： The disclosure is directed to a method and system for generating a pilot tone for an optical signal with an optical telecommunications system. The pilot tone is generated in the digital domain by modulating the data to be transmitted to a destination node within the optical telecommunications network. The modulation of the data introduces occurrence modulation to the optical signal.
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10.发明授权公开(公告)号：US09602151B1
公开(公告)日：2017-03-21
申请号：US14840457
申请日：2015-08-31
申请人： Mahdi Zamani , Ahikam Aharony , Zhuhong Zhang , Chuandong Li , Weikun Hou
发明人： Mahdi Zamani , Ahikam Aharony , Zhuhong Zhang , Chuandong Li , Weikun Hou
CPC分类号： H04B1/40 , H04L27/0014 , H04L27/32
摘要： Provided is an apparatus and method for transmitting and receiving wireless signals. A transmitting apparatus has a signal processor and a transmitter. The signal processor is configured to generate a signal having a middle channel and at least one side channel. The transmitter is configured to wirelessly transmit the signal subject to a spectral mask that has shoulder regions. According to an embodiment of the invention, the signal processor generates the signal such that each side channel is positioned in one of the shoulder regions of the spectral mask. In this manner, bandwidth from the shoulder regions can be utilized by one or more side channels. Also provided is a receiving apparatus having a receiver configured to wirelessly receive the signal, and a signal processor configured to process the signal.
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