Abstract: A signal processing system and method, and an apparatus are provided. A phase recovery apparatus may be used to: receive a feedback signal fed back by an information iteration apparatus, perform, based on the feedback signal, phase recovery on a signal output by an equalizer, and output a phase-recovered signal to a post filtering apparatus, so that the post filtering apparatus performs noise filtering on the phase-recovered signal, and outputs a noise-filtered signal to the information iteration apparatus. To be specific, the phase recovery may be performed, based on the signal fed back by the information iteration apparatus, on the signal output by the equalizer. Because output of the information iteration apparatus is more accurate in determining the signal, precision of the phase recovery can be improved, cycle skipping is reduced, and input signal quality of the post filtering apparatus is improved.

Abstract: An embodiment method includes: performing balancing processing on a data stream that includes a plurality of sub-data stream segments, and performing segment de-interleaving on a data stream obtained after the balancing processing. The method further includes separately performing forward error correction (FEC) decoding on each sub-data stream segment in a data stream obtained after the segment de-interleaving. The method further includes performing, according to a balancing termination state of each sub-data stream segment obtained after previous balancing processing, balancing processing on each sub-data stream segment obtained after the FEC decoding, and performing FEC decoding on the data stream obtained after balancing processing is performed on each sub-data stream segment. When it is determined that a preset iteration termination condition is met, the method includes outputting the data stream obtained after the FEC decoding.

Abstract: Embodiments of the present invention provide data transmission and receiving methods based on an orthogonal frequency division multiplexing technology, and an apparatus. According to the present invention, grouping and differential encoding are performed on multiple subcarriers, and further, carrier location adjustment is performed, so as to effectively improve non-linear tolerance of a multi-subcarrier system.

Abstract: Embodiments of the present invention provide a signal receiving method and a receiver. The signal receiving method includes: sequentially preprocessing a received first signal to obtain to-be-processed second signals; generating filtering coefficients for the second signals by converting colored noise of the second signals into white noise; and filtering the corresponding second signals according to the filtering coefficients. Filtering can be performed according to different channel conditions and transmission requirements, thereby improving system performance of the receiver.

Abstract: The present invention discloses an optical signal frequency calibration method and device. The method includes: receiving a first optical signal that experiences a frequency offset and that is generated by a laser in a transmitter of an access node; receiving a reference optical signal sent by a local oscillator; calculating a difference between a specified frequency difference and a frequency difference between the reference optical signal and the first optical signal; and performing frequency calibration on the first optical signal according to the difference, modulating to-be-sent uplink data by using the calibrated first optical signal, and sending the modulated uplink data to a primary node.

Abstract: Embodiments of the present invention provide a signal receiving method and a receiver. The signal receiving method includes: sequentially preprocessing a received first signal to obtain to-be-processed second signals; generating filtering coefficients for the second signals by converting colored noise of the second signals into white noise; and filtering the corresponding second signals according to the filtering coefficients. Filtering can be performed according to different channel conditions and transmission requirements, thereby improving system performance of the receiver.

Abstract: A method for sending and receiving a signal is disclosed, and a corresponding device and system. The method includes performing constellation mapping on a data stream to obtain a mapped signal, and performing pre-filtering on the mapped signal to convert the mapped signal into a narrowband signal filtered signal. The pre-filtering is finite impulse response filtering. A bandwidth of the narrowband signal filtered signal is less than bandwidth of the mapped signal, and the narrowband signal filtered signal is a baud rate signal. The method also includes performing waveform forming according to the narrowband signal filtered signal to obtain a shaped signal, and performing digital-to-analog conversion on the shaped signal to convert a shaped second signal into an analog signal, and sending the analog signal.

Abstract: The present invention is applicable to the communications field and provides a processing method for an orthogonal frequency division multiplexing (OFDM) signal and a network device. The processing method includes: obtaining an orthogonal frequency division multiplexing OFDM signal; multiplying, in a digital domain, the obtained OFDM signal by a simple harmonic wave whose frequency is fs to obtain a frequency shifted signal; and outputting and loading the frequency shifted signal by using a digital-to-analog conversion (DAC) to a driver and a modulator to send the frequency shifted OFDM signal.

Abstract: The present invention provides a cycle-slip detection method and apparatus, and a receiver. If an absolute value of a first difference obtained by subtracting a phase of a first symbol in a kth training sequence cycle from a phase of a last symbol in a (k?1)th training sequence cycle in a received signal is greater than a cycle-slip determining threshold, it is determined that a cycle-slip occurs in the kth or (k?1)th training sequence cycle. Further, if a second difference obtained by subtracting a phase of the first symbol in the (k+1)th training sequence cycle from a phase of the last symbol in the kth training sequence cycle is greater than the cycle-slip determining threshold, and signs of the first difference and the second difference are opposite, it is determined that a cycle-slip occurs in all symbols in the kth training cycle.

Abstract: A method for sending and receiving a signal is disclosed, and a corresponding device and system. The method includes performing constellation mapping on a data stream to obtain a mapped signal, and performing pre-filtering on the mapped signal to convert the mapped signal into a narrowband signal filtered signal. The pre-filtering is finite impulse response filtering. A bandwidth of the narrowband signal filtered signal is less than bandwidth of the mapped signal, and the narrowband signal filtered signal is a baud rate signal. The method also includes performing waveform forming according to the narrowband signal filtered signal to obtain a shaped signal, and performing digital-to-analog conversion on the shaped signal to convert a shaped second signal into an analog signal, and sending the analog signal.

Abstract: Embodiments of the present invention provide a channel equalization method and apparatus, and a receiver. The method includes: acquiring a channel transfer matrix according to a training sequence sent by a transmit end; acquiring an amplitude response matrix of the channel transfer matrix, and acquiring, according to the amplitude response matrix, a window length of a sliding window that is required for performing noise filtering on the channel transfer matrix; and performing noise filtering on the channel transfer matrix according to the window length of the sliding window, and performing, according to a channel transfer matrix that is obtained by means of noise filtering, channel equalization on a data payload sent by the transmit end. The channel equalization method and apparatus, and a receiver provided in the embodiments of the present invention may implement adaptive channel equalization.

Abstract: The present invention is applicable to the communications field and provides a processing method for an orthogonal frequency division multiplexing (OFDM) signal and a network device. The processing method includes: obtaining an orthogonal frequency division multiplexing OFDM signal; multiplying, in a digital domain, the obtained OFDM signal by a simple harmonic wave whose frequency is fs to obtain a frequency shifted signal; and outputting and loading the frequency shifted signal by using a digital-to-analog conversion (DAC) to a driver and a modulator to send the frequency shifted OFDM signal.

Abstract: A method for sending and receiving a signal is disclosed, and a corresponding device and system. The method includes performing constellation mapping on a data stream to obtain a mapped signal, and performing pre-filtering on the mapped signal to convert the mapped signal into a narrowband signal filtered signal. The pre-filtering is finite impulse response filtering. A bandwidth of the narrowband signal filtered signal is less than bandwidth of the mapped signal, and the narrowband signal filtered signal is a baud rate signal. The method also includes performing waveform forming according to the narrowband signal filtered signal to obtain a shaped signal, and performing digital-to-analog conversion on the shaped signal to convert a shaped second signal into an analog signal, and sending the analog signal.

Abstract: The present invention relates to a method and a device. The method includes: mixing a multi-carrier optical signal with a local optical signal having the same center frequency as that of the multi-carrier optical signal; performing photoelectric conversion and analog-to-digital conversion on an optical signal obtained through the mixing to obtain a digital signal; performing FFT on the digital signal to obtain a frequency domain signal; grouping the frequency domain signal according to each frequency band corresponding to its respective carrier in the multi-carrier optical signal, and performing IFFT on each frequency domain signal group to obtain a corresponding time domain signal for each carrier; and performing data restoration on each time domain signal corresponding to its respective carrier to obtain data carried on each carrier. The solutions of the present invention only require one set of coherent reception device, and have low cost and low power consumption.

Abstract: The present invention provides a cycle-slip detection method and apparatus, and a receiver. If an absolute value of a first difference obtained by subtracting a phase of a first symbol in a kth training sequence cycle from a phase of a last symbol in a (k?1)th training sequence cycle in a received signal is greater than a cycle-slip determining threshold, it is determined that a cycle-slip occurs in the kth or (k?1)th training sequence cycle. Further, if a second difference obtained by subtracting a phase of the first symbol in the (k+1)th training sequence cycle from a phase of the last symbol in the kth training sequence cycle is greater than the cycle-slip determining threshold, and signs of the first difference and the second difference are opposite, it is determined that a cycle-slip occurs in all symbols in the kth training cycle.

Abstract: Embodiments of the present invention provide a channel equalization method and apparatus, and a receiver. The method includes: acquiring a channel transfer matrix according to a training sequence sent by a transmit end; acquiring an amplitude response matrix of the channel transfer matrix, and acquiring, according to the amplitude response matrix, a window length of a sliding window that is required for performing noise filtering on the channel transfer matrix; and performing noise filtering on the channel transfer matrix according to the window length of the sliding window, and performing, according to a channel transfer matrix that is obtained by means of noise filtering, channel equalization on a data payload sent by the transmit end. The channel equalization method and apparatus, and a receiver provided in the embodiments of the present invention may implement adaptive channel equalization.

Abstract: A signal generating method and apparatus in the field of signal technologies are provided. The method includes: adjusting an incident angle of an optical signal entering a polarization beam splitter, so that the polarization beam splitter outputs a first optical signal and a second optical signal that have a preset power ratio; performing QPSK modulation on the first and second optical signal respectively by using a first and second externally input data streams, to obtain a first and a second QPSK optical signal; before the first QPSK optical signal and the second QPSK optical signal are input into a polarization beam combiner, adjusting a polarization state of the first or the second QPSK optical signal; when the polarization states of the two QPSK optical signals are the same, outputting a 16QAM signal; and when the polarization states of the two QPSK optical signals are orthogonal, outputting a DP-QPSK signal.

Abstract: A method for processing optical signals includes performing frequency mixing, photoelectric detection, analog/digital conversion, and dispersion compensation on received input optical signals. First-path polarization multiplexing optical signals and second-path polarization multiplexing optical signals. An initialization update process is performed on filter coefficients. Polarization compensation is performed on the first-path polarization multiplexing optical signals and the second-path polarization multiplexing optical signals by using the filter coefficients on which the initialization update is performed to obtain initialized x-path optical signals and initialized y-path optical signals. Preset x-path training sequences and y-path training sequences are synchronized by using the initialized x-path optical signals and the initialized y-path optical signals. If a synchronization result indicates that polarization cross occurs, the polarization cross is rectified.

Abstract: Embodiments of the present invention disclose an optical signal compensation device, where, a nonlinear compensation module in the optical signal compensation device adopts a new nonlinear compensation algorithm to perform nonlinear compensation on an optical signal, and during the process of performing the nonlinear compensation, it is no longer required to look up a table. Technical solutions provided in the embodiments of the present invention can effectively increase the processing speed of the nonlinear compensation, thereby reducing the overall processing delay of an optical signal compensation system.

Abstract: In the field of communication and transmission, a method and a device for receiving an OPFDM-DQPSK signal are provided. The device includes a power splitter, adapted to split the OPFDM-DQPSK signal into two beams of signals; a polarization beam splitter (PBS), adapted to splitting one of the two beams of signals into a first signal and a second signal; a demultiplexer (Demux), adapted to demultiplex the other beam of signal to obtain a third signal and a fourth signal; two delayers, adapted to delay the third signal and the fourth signal respectively; a first frequency-mixing receiving module, adapted to perform frequency-mixing receiving on the first signal and the delayed third signal; a second frequency-mixing receiving module, adapted to perform frequency-mixing receiving on the second signal and the delayed fourth signal; and a decision recovery module, adapted to recover four logical sequences by performing decision on the four electrical signals.