Method and apparatus for signal processing

Abstract

Embodiments of the present application provide a signal processing method, comprising: receiving, by a first device, a second signal from a second device, the second signal being generated based on time clipping and amplitude clipping of a first signal, the first signal being generated based on quadrature amplitude modulation mapping of a first bit sequence; performing, by the first device, quadrature amplitude demodulation mapping processing on the second signal to obtain a third signal, the third signal comprising time clipping noise and amplitude clipping noise; and performing, by the first device, time clipping noise and amplitude clipping noise processing on the third signal according to a successive interference cancellation algorithm to recover the first bit sequence. The method uses the successive interference cancellation algorithm, including decision-directed successive interference cancellation and coded-aided successive interference cancellation algorithm, to eliminate interference noise to recover the signal, which can reduce inter-carrier interference and amplitude clipping noise, and further improve system performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical communication, and more particularly, to a signal processing method and device. BACKGROUND

[0002] With the rapid development of high-rate and large-capacity optical communication technology, the performance of optical fiber communication systems such as optical access networks, short-distance optical interconnections, etc. is increasingly widely concerned. Among them, the transmission data distance of the system is relatively short, which leads to limited peak power. At the same time, as a cost-sensitive communication system, it is usually required to transmit higher-rate signals on a limited bandwidth, which leads to limited bandwidth.

[0003] Currently, to solve the problems of limited peak power and limited bandwidth, vacant subcarriers can be used to avoid high-frequency loss, or discrete Fourier transform spreading can be used to reduce peak power, but this will cause inter-carrier interference and introduce amplitude clipping noise, etc., which will further affect the performance of the optical fiber communication system.

[0004] Therefore, how to reduce inter-carrier interference and amplitude clipping noise and further improve system performance is a problem to be solved. SUMMARY

[0005] Embodiments of the present application provide a signal processing method and device, which can reduce inter-carrier interference and amplitude clipping noise and further improve system performance.

[0006] In a first aspect, a method is provided, which can be executed by a first device (for example, a receiving end) or a chip or circuit for the first device, and the present application does not limit this. For ease of description, the following is described by way of example of execution by the first device.

[0007] The method includes: receiving, by the first device, a second signal from a second device, the second signal being generated based on time clipping and amplitude clipping of a first signal, the first signal being generated based on quadrature amplitude modulation (QAM) mapping of a first bit sequence; performing, by the first device, QAM processing on the second signal to obtain a third signal, the third signal including time clipping noise and amplitude clipping noise; and performing, by the first device, time clipping noise and amplitude clipping noise processing on the third signal according to a successive interference cancellation algorithm to recover the first bit sequence.

[0008] It should be noted that the technical solution of the present application is mainly applicable to a discrete multi-tone (DMT) system.

[0009] According to the scheme provided in the application, the continuous interference cancellation algorithm is used to eliminate the time clipping noise and the amplitude clipping noise in the signal, which can reduce the inter-carrier interference and the amplitude clipping noise, and further improve the system performance.

[0010] In combination with the first aspect, in some implementations of the first aspect, the continuous interference cancellation algorithm includes a decision interference cancellation algorithm and a code-aided interference cancellation algorithm.

[0011] It should be noted that in the embodiments of the application, the continuous interference cancellation algorithm has two levels, the first level is the decision interference cancellation algorithm, and the second level is the code-aided interference cancellation algorithm. The first level interference cancellation algorithm is used to eliminate a part of the clipping noise in the signal, so that the bit error rate (BER) (which can also be referred to as the error rate) reaches the starting threshold of the second level interference cancellation algorithm.

[0012] It should be understood that the clipping noise processed by the second level interference cancellation algorithm is more accurate than the clipping noise processed by the first level interference cancellation algorithm, and therefore the error rate of the recovered bit sequence is lower.

[0013] In combination with the first aspect, in some implementations of the first aspect, the first device performs time clipping noise and amplitude clipping noise processing on the third signal according to the continuous interference cancellation algorithm, including: when the error rate of the discrete multi-tone (DMT) system is less than a first threshold, the first device performs time clipping noise and amplitude clipping noise processing on the third signal according to the decision interference cancellation algorithm.

[0014] In combination with the first aspect, in some implementations of the first aspect, the first device performs time clipping noise and amplitude clipping noise processing on the third signal according to the continuous interference cancellation algorithm, and further includes: when the error rate of the discrete multi-tone system is greater than or equal to the first threshold and less than or equal to a second threshold, the first device performs time clipping noise and amplitude clipping noise processing on the third signal according to a combination of the decision interference cancellation algorithm and the code-aided interference cancellation algorithm.

[0015] In combination with the first aspect, in some implementations of the first aspect, the first device performs time clipping noise and amplitude clipping noise processing on the third signal according to the continuous interference cancellation algorithm, and further includes: when the error rate of the discrete multi-tone system is greater than the second threshold, the first device performs time clipping noise and amplitude clipping noise processing on the third signal according to the code-aided interference cancellation algorithm; wherein the first threshold is less than the second threshold.

[0016] In the technical solution of the present application, the system bit error rate BER can be used as an evaluation criterion for system performance. Similarly, the threshold value can also be determined by using the value of BER, i.e., the first and second threshold values are different BER values. The bit error rate can be determined by calculating the ratio of the number of error bits in the bit sequence recovered at the receiving end to the total number of bits sent at the transmitting end.

[0017] It should be understood that the smaller the bit error rate BER, the better the system performance. Conversely, the larger the bit error rate BER, the worse the system performance.

[0018] In this implementation, by comparing the relationship between the system performance and the threshold value, different interference cancellation algorithms are selected to solve the interference caused by time clipping and amplitude clipping to recover the signal. Not only can the problem of system frequency being limited by power be solved, but also the appropriate algorithm combination can be made according to the receiving performance to obtain a balance between performance and complexity.

[0019] In combination with the first aspect, in some implementations of the first aspect, the first device receives the water filling parameter and the clipping parameter from the second device.

[0020] It should be noted that before the service transmission, the transmitting end can transmit the water filling parameter and the clipping parameter through the control transmission link of the entire system. Here, the control transmission link can be understood as a normal transmission link, which does not need to transmit additional parameters to realize the communication between the transmitting end and the receiving end.

[0021] In combination with the first aspect, in some implementations of the first aspect, the first device performs time clipping noise and amplitude clipping noise processing on the third signal according to the decision interference cancellation algorithm, including: the first device performs QAM decision processing on the third signal based on the water filling parameter to obtain a decision QAM signal; and the first device performs time clipping and amplitude clipping processing on the decision QAM signal to obtain a first QAM signal without clipping noise.

[0022] In combination with the first aspect, in some implementations of the first aspect, the first device performs time clipping and amplitude clipping processing on the decision QAM signal based on the clipping parameter to obtain the first QAM signal without clipping noise, including: the first device generates a first DMT signal by performing inverse Fourier transform processing on the decision QAM signal; the first device performs time clipping and amplitude clipping on the first DMT signal based on the clipping parameter, and performs Fourier transform processing to obtain a fourth signal, the fourth signal including time clipping noise and amplitude clipping noise; and the first device obtains the first QAM signal without clipping noise based on the fourth signal, the decision QAM signal, and the third signal.

[0023] For example, the fourth signal (i.e., the QAM signal with clipping noise) minus the decision QAM signal can obtain the estimated clipping noise N1; and the third signal (i.e., the initially recovered QAM signal) minus the estimated clipping noise N1 can obtain the first QAM signal with clipping noise removed.

[0024] In this implementation, according to the decision interference cancellation algorithm, the signal is processed in time clipping noise and amplitude clipping noise, and a part of the clipping noise of the signal can be cancelled first.

[0025] Optionally, the first QAM signal with clipping noise removed can continue to iterate in the first-stage interference cancellation algorithm. As the number of iterations increases, the first QAM signal with clipping noise removed is more and more accurate, and when the accuracy of the first QAM signal with clipping noise removed is almost no longer improved, the second-stage interference cancellation algorithm can be entered.

[0026] In combination with the first aspect, in some implementations of the first aspect, the first device performs time clipping noise and amplitude clipping noise processing on the third signal according to the coded auxiliary interference cancellation algorithm, including: the first device performs QAM demapping processing on the first QAM signal with clipping noise removed to generate a second bit sequence; the first device performs de-interleaving and channel decoding processing on the second bit sequence to generate a third bit sequence; and the first device performs time clipping noise and amplitude clipping noise processing on the third bit sequence to obtain a second QAM signal with clipping noise removed.

[0027] In this implementation, according to the coded auxiliary interference cancellation algorithm, the time clipping noise and amplitude clipping noise processing is performed on the third signal, and the bit error rate of the second QAM signal with clipping noise removed is greatly reduced compared with the first-stage interference cancellation algorithm.

[0028] In combination with the first aspect, in some implementations of the first aspect, the first device performs time clipping noise and amplitude clipping noise processing on the third bit sequence to obtain the second QAM signal with clipping noise removed, including: the first device performs channel coding and interleaving processing on the third bit sequence to generate a second discrete multi-tone signal; the first device performs QAM mapping processing on the second discrete multi-tone signal to obtain a fifth signal; the first device performs time clipping and amplitude clipping processing on the fifth signal to obtain a sixth signal, the sixth signal including time clipping noise and amplitude clipping noise; and the first device obtains the second QAM signal with clipping noise removed based on the sixth signal, the decision QAM signal and the fifth signal.

[0029] Optionally, the first device performs time clipping and amplitude clipping processing on the fifth signal to obtain the sixth signal, including: the first device performs inverse Fourier transform, time clipping and amplitude clipping, and Fourier transform processing on the fifth signal to obtain the sixth signal.

[0030] For example, the sixth signal (i.e., the QAM signal with clipping noise) is subtracted by the fifth signal (i.e., the QAM signal with clipping noise) to obtain the estimated clipping noise N2. The third signal (i.e., the originally recovered QAM signal) is subtracted by the estimated clipping noise N2 to obtain the second QAM signal with clipping noise removed.

[0031] In this implementation, the third bit sequence can be subjected to QAM mapping processing after channel coding and interleaving. Based on the error correction capability of the channel coding on the bit sequence, the estimated clipping noise N2 is more accurate than the first-level estimated clipping noise N1.

[0032] It should be noted that when the error rate of the third bit sequence after error correction is equal to the preset threshold, the estimated clipping noise N2 can be considered completely accurate, and at this time, the fifth signal has no clipping noise.

[0033] In combination with the first aspect, in some implementations of the first aspect, the error rate of the third bit sequence is less than the preset threshold.

[0034] The preset threshold can be determined by the coding condition.

[0035] In this implementation, a possible implementation of channel decoding is provided. In order to overcome the defect of large channel decoding complexity, the channel decoding can adopt an incomplete decoding manner to reduce the number of decoding iterations. That is, when the error rate of the decoded bit sequence is lower than the preset threshold, the decoded bit sequence is directly output without completing all iteration numbers.

[0036] Secondly, a signal processing method is provided. The method can be executed by a second device (for example, a sending end) or a chip or circuit for the second device, and the present application does not limit this. For ease of description, the following takes the second device as an example for description.

[0037] The method includes: the second device generates a first bit sequence; the second device performs QAM mapping processing on the first bit sequence to generate a first signal; the second device performs time clipping and amplitude clipping processing on the first signal to obtain a second signal; and the second device sends the second signal to a first device.

[0038] It should be noted that the technical solution of the present application is mainly applicable to a DMT system.

[0039] According to the scheme provided by the present application, by performing time clipping and amplitude clipping processing on the first signal, interference noise is eliminated to recover the signal, which can reduce inter-carrier interference and amplitude clipping noise, and further improve system performance.

[0040] It should be noted that the second device and the first device in the embodiments of the present application can be specifically implemented as an optical transmission device.

[0041] With reference to the second aspect, in some implementations of the second aspect, the time clipping and amplitude clipping processing of the second device on the first signal comprises: the second device performing time clipping and amplitude clipping processing on the first signal according to a time clipping ratio and an amplitude clipping ratio respectively.

[0042] In this implementation, the time clipping operation can shorten the period of the DMT symbol, which is equivalent to increasing the signal rate. Therefore, the DMT signal with time clipping can achieve the same rate in a lower bandwidth, thereby reducing the impact of bandwidth limitation; the amplitude clipping can directly reduce the peak-to-average power ratio (PAPR) of the signal, thereby obtaining a higher signal-to-noise ratio (SNR) in a peak power limited system, and improving the system performance.

[0043] With reference to the second aspect, in some implementations of the second aspect, the time clipping ratio a satisfies: a=(T-Tc) / T, and the amplitude clipping ratio b satisfies: b=A^2 / σ^2; wherein T is the period of the first signal in the time domain, Tc is the time of the first signal being clipped in the time domain, A is the maximum amplitude of the first signal after being clipped, and σ is the root mean square value of the first signal.

[0044] In this implementation, the time clipping ratio and the amplitude clipping ratio are defined to provide possible implementation of time clipping and amplitude clipping at the transmitting end.

[0045] With reference to the second aspect, in some implementations of the second aspect, the QAM mapping processing of the second device on the first bit sequence comprises: the second device performing QAM mapping processing on the first bit sequence according to a power and bit allocation algorithm based on the water-filling principle.

[0046] In this implementation, the QAM mapping processing by the power and bit allocation algorithm based on the water-filling principle can reduce the computational complexity. At the same time, the channel resources can be reasonably utilized, and different transmission powers can be allocated according to the quality of each subchannel.

[0047] With reference to the second aspect, in some implementations of the second aspect, the second device sends the water-filling parameters and the clipping parameters to the first device.

[0048] For example, the water-filling parameters include a data bit rate, available power, bit error rate BER, etc.

[0049] It should be noted that before the service transmission, the transmitting end can transmit the water injection parameters and the clipping parameters through a control transmission link of the whole system. Here, the control transmission link can be understood as a common transmission link, which does not need to pass additional parameters to realize the communication between the transmitting end and the receiving end.

[0050] In a third aspect, an apparatus is provided, comprising: a transceiver configured to receive, by a first device, a second signal from a second device, the second signal being generated based on time clipping and amplitude clipping of a first signal, the first signal being generated based on QAM mapping of a first bit sequence; and a processor configured to perform, by the first device, QAM de-mapping on the second signal to obtain a third signal, the third signal comprising time clipping noise and amplitude clipping noise; and the processor is further configured to perform, by the first device, time clipping noise and amplitude clipping noise processing on the third signal according to a successive interference cancellation algorithm to recover the first bit sequence.

[0051] With reference to the third aspect, in some implementations of the third aspect, the successive interference cancellation algorithm comprises a decision-directed interference cancellation algorithm and / or a coded-aided interference cancellation algorithm.

[0052] With reference to the third aspect, in some implementations of the third aspect, the processor is further configured to perform, by the first device, time clipping noise and amplitude clipping noise processing on the third signal according to the decision-directed interference cancellation algorithm when a bit error rate of the discrete multi-tone system is less than a first threshold.

[0053] With reference to the third aspect, in some implementations of the third aspect, the processor is further configured to perform, by the first device, time clipping noise and amplitude clipping noise processing on the third signal according to a combination of the decision-directed interference cancellation algorithm and the coded-aided interference cancellation algorithm when the bit error rate of the discrete multi-tone system is greater than or equal to the first threshold and less than or equal to a second threshold.

[0054] With reference to the third aspect, in some implementations of the third aspect, the processor is further configured to perform, by the first device, time clipping noise and amplitude clipping noise processing on the third signal according to the coded-aided decision-directed interference cancellation algorithm when the bit error rate of the discrete multi-tone system is greater than the second threshold.

[0055] The first threshold is less than the second threshold.

[0056] With reference to the third aspect, in some implementations of the third aspect, the transceiver is further configured to receive, by the first device, water injection parameters and clipping parameters from the second device.

[0057] In some implementations of the third aspect, in combination with the third aspect, the processing unit is further configured to: perform, by the first device, QAM decision processing on the third signal based on the water-filling parameters to obtain a decision QAM signal; and perform, by the first device, time clipping and amplitude clipping processing on the decision QAM signal based on the clipping parameters to obtain the first QAM signal with clipping noise removed.

[0058] In some implementations of the third aspect, in combination with the third aspect, the processing unit is further configured to: perform, by the first device, time clipping and amplitude clipping processing on the decision QAM signal based on the clipping parameters to obtain the first QAM signal with clipping noise removed, including: generating, by the first device, a first DMT signal after inverse Fourier transform processing on the decision QAM signal; performing, by the first device, time clipping and amplitude clipping on the first DMT signal based on the clipping parameters, and Fourier transform processing to obtain a fourth signal, the fourth signal including time clipping noise and amplitude clipping noise; and obtaining, by the first device, the first QAM signal with clipping noise removed based on the fourth signal, the decision QAM signal, and the third signal.

[0059] In some implementations of the third aspect, in combination with the third aspect, the processing unit is further configured to: perform, by the first device, QAM demapping processing on the first QAM signal with clipping noise removed to generate a second bit sequence; perform, by the first device, de-interleaving and channel decoding processing on the second bit sequence to generate a third bit sequence; and perform, by the first device, time clipping noise and amplitude clipping noise processing on the third bit sequence to obtain a second QAM signal with clipping noise removed.

[0060] In some implementations of the third aspect, in combination with the third aspect, the processing unit is further configured to: perform, by the first device, channel coding and interleaving processing on the third bit sequence to generate a second DMT signal; perform, by the first device, QAM mapping processing on the second DMT signal to obtain a fifth signal; perform, by the first device, time clipping and amplitude clipping processing on the fifth signal to obtain a sixth signal, the sixth signal including time clipping noise and amplitude clipping noise; and obtain, by the first device, the second QAM signal with clipping noise removed based on the sixth signal, the decision QAM signal, and the fifth signal.

[0061] Optionally, the processing unit is further configured to: perform, by the first device, time clipping and amplitude clipping processing on the fifth signal to obtain the sixth signal, including: performing, by the first device, inverse Fourier transform, time clipping and amplitude clipping, and Fourier transform processing on the fifth signal to obtain the sixth signal.

[0062] In some implementations of the third aspect, in combination with the third aspect, a bit error rate of the third bit sequence is less than a preset threshold.

[0063] In a fourth aspect, an apparatus is provided, comprising: a processing unit configured to cause a second device to generate a first bit sequence; the processing unit is further configured to cause the second device to perform a Quadrature Amplitude Modulation (QAM) mapping process on the first bit sequence to generate a first signal; the processing unit is further configured to cause the second device to perform a time clipping and amplitude clipping process on the first signal to obtain a second signal; and a transceiver configured to cause the second device to transmit the second signal to a first device.

[0064] With reference to the fourth aspect, in some implementations of the fourth aspect, the processing unit is further configured to cause the second device to perform the time clipping and the amplitude clipping on the first signal according to a time clipping ratio and an amplitude clipping ratio, respectively.

[0065] With reference to the fourth aspect, in some implementations of the fourth aspect, the time clipping ratio a satisfies a=(T-Tc) / T, and the amplitude clipping ratio b satisfies b=A^2 / σ^2; where T is a period of the first signal in time domain, Tc is a time of the first signal being clipped in time domain, A is a maximum amplitude of the first signal after being clipped, and σ is a root mean square value of the first signal.

[0066] With reference to the fourth aspect, in some implementations of the fourth aspect, the processing unit is further configured to cause the second device to perform the QAM mapping process on the first bit sequence according to a power and bit allocation algorithm based on a water-filling principle.

[0067] With reference to the fourth aspect, in some implementations of the fourth aspect, the transceiver is further configured to cause the second device to transmit, to the first device, water-filling parameters and clipping parameters.

[0068] In a fifth aspect, a communication apparatus is provided, comprising: a processor, and optionally, a memory, the processor being configured to control a transceiver to transceive signals, the memory being configured to store a computer program, the processor being configured to invoke and run the computer program from the memory, so that a first device (e.g., a receiving end) performs the method in the first aspect or any possible implementation of the first aspect.

[0069] Optionally, the processor is one or more, and the memory is one or more.

[0070] Optionally, the memory can be integrated with the processor, or the memory is disposed separately from the processor.

[0071] Optionally, the first device further comprises a transceiver, which specifically can be a transmitter (transmitter) and a receiver (receiver).

[0072] In a sixth aspect, a communication apparatus is provided, which comprises a processor, and optionally, a memory, the processor configured to control a transceiver to transceive signals, and the memory configured to store a computer program, the processor configured to invoke and run the computer program from the memory, so that the second device (e.g., a transmitter) performs the method in the second aspect or in any possible implementation of the second aspect.

[0073] Optionally, the processor is one or more, and the memory is one or more.

[0074] Optionally, the memory can be integrated with the processor, or the memory can be located separately from the processor.

[0075] Optionally, the second device further comprises a transceiver, which can be specifically a transmitter (transmitter) and a receiver (receiver).

[0076] In a seventh aspect, a communication system is provided, which comprises a first device configured to perform the method in the first aspect or in any possible implementation of the first aspect, and a second device configured to perform the method in the second aspect or in any possible implementation of the second aspect.

[0077] In an eighth aspect, a computer-readable storage medium is provided, which stores a computer program or code, which, when executed on a computer, causes the computer to perform the method in the first aspect or in any possible implementation of the first aspect as a first device, or causes the computer to perform the method in the second aspect or in any possible implementation of the second aspect as a second device.

[0078] In a ninth aspect, a chip is provided, which comprises at least one processor coupled with a memory, the memory configured to store a computer program, and the processor configured to invoke and run the computer program from the memory, so that a first device installed with the chip performs the method in the first aspect or in any possible implementation of the first aspect, or so that a second device installed with the chip performs the method in the second aspect or in any possible implementation of the second aspect.

[0079] Optionally, the chip can comprise an input circuit or interface for transmitting information or data, and an output circuit or interface for receiving information or data.

[0080] In a tenth aspect, a computer program product is provided, which includes computer program codes, when the computer program codes are run by a first device, the computer program codes cause the network management device to perform the method in the first aspect or any possible implementation of the first aspect; or, when the computer program codes are run by a second device, the computer program codes cause the network element device to perform the method in the second aspect or any possible implementation of the second aspect. BRIEF DESCRIPTION OF DRAWINGS

[0081] Figure 1 is an example schematic diagram of a communication system to which the present application is applicable.

[0082] Figure 2 is an example schematic diagram of a method of signal processing to which the present application is applicable.

[0083] Figure 3 is an example schematic diagram of an implementation process of time clipping and amplitude clipping to which the present application is applicable.

[0084] Figure 4 is an example schematic diagram of an implementation process of a two-stage interference cancellation algorithm to which the present application is applicable.

[0085] Figure 5 is an example schematic diagram of an implementation of a partial decoding module to which the present application is applicable.

[0086] Figure 6 is an example schematic diagram of a flow of signal processing to which the present application is applicable.

[0087] Figure 7 is an example schematic diagram of a result of calculation using a two-stage interference cancellation algorithm to which the present application is applicable.

[0088] Figure 8 is an example schematic diagram of an apparatus of signal processing to which the present application is applicable.

[0089] Figure 9 is another example schematic diagram of an apparatus of signal processing to which the present application is applicable. DETAILED DESCRIPTION

[0090] The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

[0091] The embodiments of the present application can be applied to an optical communication system, which includes but is not limited to an optical access network (OAN), a short-distance optical interconnection, an optical transport network (OTN), a passive optical network (PON), a wavelength division multiplexing (WDM) network, and other cost-sensitive fiber communication systems.

[0092] The embodiments of the present application will be described below in conjunction with Figure 1 The optical communication system to which the signal processing method provided by the present application is applied will be described by way of example.

[0093] The optical communication system can include a media access control address (MAC), a digital signal processing (DSP), an analog digital converter (ADC), a transmitter and a receiver at the transmitting end, a MAC, a DSP and an ADC at the receiving end, and the like. The transmitter and the receiver are connected by an optical fiber, which is used for data transmission between devices.

[0094] Specifically, the optical transmitter in the system converts an electrical signal into an optical signal, injects the generated optical signal into an optical fiber, and sends the modulated optical signal into an optical receiver after transmission through the optical fiber. The optical receiver restores the optical signal transmitted by the optical fiber into the original electrical signal, i.e., completes the transmission of the signal.

[0095] Of course, the optical communication device provided above is only an example, and other devices can be included in actual application scenarios. For example, optical and electrical devices at the transmitting end (direct laser, electrical absorption modulator, Mach-Zehnder modulator, etc.); for example, optical and electrical devices at the receiving end (photodiode detector, avalanche diode detector, etc.). The present application does not make specific limitations in this regard.

[0096] It should be noted that the digital signal processing device at the transmitting end and the receiving end is mainly concerned in the technical solution of the present application. For example, the transmitting end performs QAM mapping, channel coding, inverse fast Fourier transform (IFFT), time clipping and amplitude clipping on the signal. The receiving end performs fast Fourier transform (FFT), channel equalization, interference cancellation, channel decoding, etc.

[0097] For the convenience of understanding the embodiments of the present application, first, several concepts involved in the present application are simply explained.

[0098] 1. Discrete Multi-Tone (DMT) technology

[0099] DMT is a kind of multi-carrier modulation and demodulation technology. The sending end uniformly divides the available bandwidth of a channel into N / 2 independent sub-channels by using an N-point inverse fast Fourier transform (IFFT), and performs a separate quadrature amplitude modulation (QAM) on each sub-channel. The N time-domain samples obtained by the IFFT are called a DMT symbol. The receiving end recovers the original sending data by using a fast Fourier transform (FFT) after receiving a DMT symbol. DMT has more advantages than the traditional single-carrier modulation, including anti-frequency selective fading and anti-inter-symbol interference.

[0100] 2. Peak-to-Average Power Ratio (PAPR)

[0101] PAPR can also be called peak-to-average power ratio, or peak factor, which is a measurement parameter of a waveform, equal to a ratio obtained by dividing the square of the amplitude of the waveform by the square of the effective value (root mean square, RMS). PAPR can also be understood as a ratio of peak power to average power. The peak power is the instantaneous power of a shoulder peak appearing with a certain probability, and the average power is the actual power output by the system.

[0102] 3. Signal-to-Noise Ratio (SNR)

[0103] SNR refers to the ratio of signal to noise in a device or system. The signal refers to an electronic signal from outside the device that needs to be processed by the device, and the noise refers to an irregular additional signal (or information) that does not exist in the original signal after passing through the device, and the signal does not change with the change of the original signal. Among them, the measurement unit of signal-to-noise ratio is dB.

[0104] 4. Quadrature Amplitude Modulation (QAM)

[0105] QAM is a kind of double sideband amplitude modulation that uses two independent baseband signals to suppress two mutually orthogonal carriers of the same frequency. The orthogonality of the frequency spectrum of the modulated signal in the same bandwidth is used to realize the transmission of two parallel digital information. QAM is a combination of quadrature carrier modulation technology and multi-level amplitude shift keying, with both amplitude and phase changing.

[0106] The principle of the QAM modulator is that the sending data is divided into two paths in the bit / symbol encoder (also called a serial-to-parallel converter), each being 1 / 2 of the original two signals, and then multiplied by a pair of orthogonal modulation components, and the sum is output. The receiving end completes the opposite process, and the quadrature demodulation outputs two opposite code streams. The equalizer compensates for the distortion caused by the channel, and the decision maker identifies the complex signal and maps it back to the original binary signal.

[0107] 5. Digital Signal Processing, DSP

[0108] DSP is the theory and techniques of representing and processing signals in a digital manner. Digital signal processing is a subset of signal processing. The purpose of digital signal processing is to measure or filter real-world continuous analog signals. Therefore, before digital signal processing, the signal needs to be converted from the analog domain to the digital domain, usually through an analog-to-digital converter. The output of digital signal processing often also needs to be converted to the analog domain, usually through a digital-to-analog converter.

[0109] 6. Forward Error Correction, FEC

[0110] FEC, also known as forward error correction, is a method to increase the reliability of data communication. In a one-way communication channel, once an error is found, the receiver will have no right to request transmission again. FEC is a method of transmitting redundant information using data, which allows the receiver to reconstruct the data when errors occur during transmission.

[0111] 7. Received Optical Power, ROP

[0112] Optical power is the energy accumulated by an optical signal in a unit of time. The units of optical power include milliwatts (mw) and decibels milliwatts (dbm). Received optical power is used to represent the strength of an optical signal.

[0113] 8. Digital-to-Analog Converter, DAC, and Analog-to-Digital Converter, ADC

[0114] DAC, also known as D / A converter, is a converter that converts binary digital discrete signals into analog signals based on standard quantities (or reference quantities). D / A converter is basically composed of four parts: weight resistance network, operational amplifier, reference power supply, and analog switch.

[0115] ADC, also known as A / D converter, is an electronic element that converts continuous analog signals into discrete digital signals. It can realize the function of converting input analog electrical signals into digital signal output. The output digital signal is used for digital signal processing.

[0116] Therefore, analog-to-digital converter and / or digital-to-analog converter are essential elements of digital signal processing.

[0117] With the increasing demand for data services, large-capacity high-speed optical fiber transmission network has gradually become the main direction of information transmission. The continuous innovation of new optical fiber communication technologies also promotes the increase of optical fiber transmission distance and transmission capacity year by year. Among them, optical access network, short-distance optical interconnection and other optical fiber communication systems usually do not need to use optical amplifiers due to the short transmission distance. Moreover, in order to reduce the cost, such systems need to transmit higher rate signals on limited bandwidth as much as possible. Therefore, optical access network, short-distance optical interconnection and other systems are also considered as a bandwidth-limited and peak power-limited system.

[0118] As a high spectral efficiency signal, discrete multi-tone (DMT) can effectively utilize the bandwidth and signal-to-noise ratio (SNR) of the system through bit allocation and power allocation. However, due to the poor high-frequency response of low-cost devices, the performance of high-frequency subcarriers of the DMT signal will be seriously affected, thereby degrading the overall system performance. In addition, due to the high peak-to-average power ratio (PAPR) of the DMT signal, the transmission signal with high PAPR has a lower average power in the peak power-limited system, thereby resulting in a lower SNR and making the system performance suboptimal. At the same time, the high PAPR signal is more sensitive to quantization noise, so the DMT system needs a digital-to-analog converter and an analog-to-digital converter with a high number of quantization bits.

[0119] Currently, in order to avoid the above problems, there are the following solutions:

[0120] Firstly, in order to solve the problem of limited system bandwidth, the idle subcarriers can be used to avoid high-frequency damage. The subcarriers are an important way to realize frequency division multiplexing and improve bandwidth utilization. However, this method may cause the system capacity to decrease. Further, the spectrum compression and time domain clipping can be used to effectively avoid high-frequency damage while ensuring the system capacity unchanged. However, both spectrum compression and time domain clipping will introduce inter-carrier interference.

[0121] Secondly, in order to solve the problem of limited peak power of the system, the discrete Fourier transform (DFT) extension and amplitude clipping can be used. However, the DFT extension scheme will result in a decrease in the number of subcarriers and a decrease in the frequency resolution of bit allocation and power allocation. Although the amplitude clipping scheme can directly and effectively reduce the PAPR of the DMT signal, it will introduce amplitude clipping noise.

[0122] In summary, the above solutions can solve the problems of limited system bandwidth and limited peak power of the system, respectively, but introduce inter-carrier interference and amplitude clipping noise. Therefore, how to reduce the inter-carrier interference and amplitude clipping noise at the same time and further improve the system performance is a technical problem to be solved.

[0123] Therefore, the application provides a signal processing method and device, which performs time clipping and amplitude clipping on a signal at a transmitting end to overcome the influence of bandwidth limitation and peak power limitation on system performance. The time clipping noise and amplitude clipping noise are processed at a receiving end through an interference cancellation algorithm to reduce the interference caused by time clipping and amplitude clipping and improve the performance of an optical fiber communication system.

[0124] In order to facilitate understanding of the embodiments of the application, the following points are explained:

[0125] In various embodiments of the application, the terms and / or descriptions of different embodiments are consistent and can be mutually referred to if there is no special description and no logical conflict. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0126] In the application, "at least one" means one or more, and "multiple" means two or more. "And / or" describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent the following three cases: A exists alone, A and B exist together, and B exists alone. Wherein, A and B can be singular or plural. In the character description of the application, the character " / " generally represents an "or" relationship between the front and rear associated objects.

[0127] In the application, "for indicating" can include "for directly indicating" and "for indirectly indicating". When describing that certain indication information is used to indicate A, it can include that the indication information directly indicates A or indirectly indicates A, and does not mean that A must be carried in the indication information.

[0128] In addition, the specific indication method can also be various existing indication methods, such as but not limited to the above-mentioned indication methods and various combinations thereof. The specific details of various indication methods can refer to the prior art, and will not be described herein. As can be seen from the above, for example, when multiple information of the same type needs to be indicated, the indication methods of different information can be different. In the specific implementation process, the required indication method can be selected according to the specific needs, and the application embodiments do not limit the selected indication method. In this way, the indication method involved in the application embodiments should be understood as covering various methods that can enable the to-be-indicated party to know the to-be-indicated information.

[0129] It can be understood that in the embodiments shown below, "first", "second", and various numerical numbers are only distinguished for the convenience of description, and are not used to limit the scope of the embodiments of the application. The size of the serial number of each process does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the application.

[0130] In the embodiments of the present application, the descriptions such as "when", "in the case of", "if", and "whether" all refer to the device making corresponding processing under certain objective condition, not limited in time, and the device does not necessarily have a judgment action when implemented, nor does it mean that there are other limitations.

[0131] The technical solutions provided by the present application will be described in detail below with reference to the drawings.

[0132] Figure 2 is an example of a signal processing method 200 applicable to the technical solutions of the present application. The method can be implemented by the first device and the second device, or by modules or units in the first device and the second device (for example, chips, circuits, system on chip (SOC), etc.).

[0133] To facilitate understanding of the embodiments of the present application, the first device is taken as an example of the receiving end, and the second device is taken as an example of the transmitting end, and the technical solutions provided by the present application are exemplarily described. As shown in Figure 2 The specific implementation steps include:

[0134] S210, the transmitting end (i.e., an example of the second device) generates a first bit sequence.

[0135] The first bit sequence is composed of bit 0 and 1.

[0136] For example, the bit sequence corresponding to 3 bits has 8 kinds, which are 000, 001, 010, 011, 100, 101, 110, and 111.

[0137] S220, the transmitting end performs quadrature amplitude modulation (QAM) mapping processing on the first bit sequence to generate a first signal.

[0138] For example, the first signal can be an orthogonal frequency division multiplexing (OFDM) signal.

[0139] It should be understood that the technical solutions of the present application are applicable to discrete multi-tone (DMT) systems, and the signals involved in the present application can be understood as discrete multi-tone (DMT) signals.

[0140] It should be noted that the transmitting end can perform channel coding on the first bit sequence.

[0141] It should be understood that channel coding refers to the theory and method for improving channel reliability implemented by a channel encoder and a decoder, i.e., channel coding has certain error correction capability and anti-interference capability. Channel coding includes channel coding theorem and constructive coding method.

[0142] The specific channel coding manner can refer to the prior art, which will not be described here.

[0143] In a possible implementation, the transmitting end performs QAM mapping processing on the SNR of each subcarrier through bit and power water injection, and generates the first signal by using IFFT.

[0144] It should be understood that the bit and power water injection can also be understood as a fast power and bit allocation algorithm based on water injection principle. The water injection algorithm is a classic power allocation algorithm for maximizing the system capacity in a multi-channel wireless communication system. The water injection parameters include the data bit rate, the available power, and the bit error rate (BER).

[0145] In an actual multi-channel wireless communication system, the frequency selectivity of each subchannel is different, and each subchannel has different transmission capability. Different powers are adaptively allocated to each subchannel according to the channel condition, so that the system performance can be optimized. When the transmitting end knows the channel state information (CSI), the power of each transmitting antenna can be allocated by using the water injection principle. In the case of power limitation, the water injection principle can be derived by maximizing the capacity of a MIMO channel.

[0146] The power allocation algorithm based on the water injection principle can be regarded as decomposing the channel H into m independent and parallel subchannels, and allocating different transmitting bits and transmitting powers according to the quality of the subchannels. More transmitting bits can be allocated to a good channel, and the bits can be reduced accordingly for a poor channel. No bit can be allocated to a particularly poor channel. In the bit allocation algorithm, the commonly used rectangular QAM constellation includes 4QAM, 8QAM, 16QAM, 32QAM, 64QAM, 128QAM, and 256QAM, and the number of bits corresponding to each constellation point is 2, 3, 4, 5, 6, 7, and 8, respectively. The power allocation algorithm is used to modulate the transmitting power of each subchannel, so that all the subchannels can work in the best state.

[0147] In S230, the transmitting end performs time clipping and amplitude clipping on the first signal to obtain a second signal.

[0148] For example, the transmitting end performs time clipping and amplitude clipping on the OFDM signal according to the time clipping ratio and the amplitude clipping ratio, respectively, to obtain the second signal.

[0149] For example, the second signal can be an OFDM signal.

[0150] It should be noted that the transmitting end can convert the digital signal into an electrical quadrature frequency division multiplexing signal through a digital-to-analog converter.

[0151] Specifically, Figure 3 is an example of an implementation process of time clipping and amplitude clipping applicable to the present application. As shown, Figure 3 The discrete multi-tone (DMT) signal can be shortened in a symbol period through time clipping and reduced in PAPR through amplitude clipping.

[0152] The time clipping refers to clipping a signal of a time Tc in the time domain within a DMT symbol period T. Therefore, the time clipping ratio a is defined as (T-Tc) / T. The time clipping can shorten the DMT symbol period, which is equivalent to increasing the signal rate.

[0153] That is, the DMT signal with time clipping can achieve the same rate in a lower bandwidth, thereby reducing the impact of bandwidth limitation.

[0154] Similarly, the amplitude of the signal is set to A, and the amplitude clipping refers to clipping the amplitude of the DMT signal according to the upper limit A, that is, the maximum amplitude of the signal after clipping is equal to A. Therefore, the amplitude clipping ratio b is defined as A^2 / σ^2. A is the maximum amplitude of the signal after clipping, and σ is the root mean square (RMS) value of the signal.

[0155] In this implementation, the amplitude clipping can reduce the PAPR of the DMT signal, thereby obtaining a higher SNR in a peak power limited system and improving the system performance.

[0156] That is, the technical solution of the present application can flexibly select time clipping or amplitude clipping according to the characteristics of the transmitting end and the performance requirements of the system, and can overcome the impact of bandwidth limitation and peak power limitation on the system performance through time clipping and amplitude clipping. The time clipping can be understood as removing a certain sequence, and the amplitude clipping can be understood as limiting the maximum amplitude of the sequence.

[0157] For example, the sequence length of the signal is L, and the amplitude is A. Through time clipping, the sequence length of the tail part of the sequence can be clipped by N (N

[0158] Based on this, if the value of N is reduced and the value of P is increased, the inter-carrier interference and amplitude clipping noise can be correspondingly reduced.

[0159] S240, the transmitting end sends a second signal to the receiving end (i.e., an example of the first device).

[0160] Correspondingly, the receiving end receives the second signal from the transmitting end.

[0161] S250, the receiving end performs QAM demapping processing on the second signal to obtain a third signal.

[0162] The third signal includes time clipping noise and amplitude clipping noise.

[0163] For example, the receiving end converts the electrical signal into a digital signal through an analog-to-digital converter, and then obtains the third signal through fast Fourier transform (FFT) and channel equalization.

[0164] The third signal can be a recovered QAM signal, in which case the QAM signal contains time clipping noise and amplitude clipping noise.

[0165] S260, the receiving end processes the third signal according to a successive interference cancellation algorithm to recover the first bit sequence.

[0166] It should be noted that the successive interference cancellation algorithm proposed in the present application has a two-stage interference cancellation algorithm compared with the traditional interference cancellation algorithm. The first stage is a decision interference cancellation algorithm, and the second stage is a coding-aided interference cancellation algorithm.

[0167] In the technical solution of the present application, the system bit error rate (BER) can be used as an evaluation standard for system performance. The threshold value can also be determined using the value of BER, i.e., the first and second thresholds are different BER values. The bit error rate can be determined by calculating the ratio of the number of error bits in the recovered bit sequence to the total number of bits sent.

[0168] It should be understood that the smaller the bit error rate (BER), the better the system performance. Conversely, the larger the bit error rate (BER), the worse the system performance.

[0169] In one possible implementation, when the system bit error rate is less than the first threshold, the decision successive interference cancellation algorithm is selected to obtain the best performance; when the system bit error rate is between the first threshold and the second threshold, the decision successive interference cancellation algorithm and the coding-aided successive interference cancellation algorithm are combined, i.e., the decision successive interference cancellation algorithm can be used to eliminate part of the interference of the signal, and the coding-aided successive interference cancellation algorithm can be used to recover a more accurate signal. In the case of maintaining certain performance requirements, the complexity and time delay are reduced, and the switching of the two algorithms is controlled by the size of a certain intermediate variable of the algorithm; when the system bit error rate is greater than the second threshold, the coding-aided successive interference cancellation algorithm is selected, which can realize the function of interference cancellation even in the case of poor overall system performance. The first threshold is less than the second threshold.

[0170] For example, the first threshold BER=a, the second threshold BER=b, a

[0171] In this implementation, the same algorithm process can be used to solve the problem of system frequency limited by power, and the corresponding algorithm combination can be made according to the receiving performance to obtain the balance between performance and complexity.

[0172] It should be noted that when the system error rate is between the first threshold and the second threshold, an intermediate variable can be found in the algorithm implementation process, which has a positive relationship with the system BER. The size of the intermediate variable is determined by the size of the system BER. Further, the interference cancellation algorithm used is determined according to the threshold range.

[0173] Optionally, the second device sends the water filling parameter and the clipping parameter to the first device.

[0174] Correspondingly, the first device receives the water filling parameter and the clipping parameter from the second device.

[0175] It should be understood that the transmitting end can not carry the water filling parameter and the clipping parameter when transmitting the signal. However, the transmitting end can transmit the water filling parameter and the clipping parameter through the control transmission link of the entire system before the service transmission. Here, the control transmission link can be understood as a normal transmission link, which does not need to transmit additional parameters to realize the communication between the transmitting end and the receiving end.

[0176] Specifically, Figure 4 is an example of the implementation process of the two-stage interference cancellation algorithm applicable to the present application. As shown in Figure 4 (a) is the first-stage decision interference cancellation algorithm, and (b) is the second-stage code-aided interference cancellation algorithm. Through the first-stage interference cancellation algorithm, a part of the clipping noise can be eliminated, so that the error rate reaches the starting threshold of the second-stage interference cancellation algorithm. Through the second-stage interference cancellation algorithm, the clipping noise can be reduced, the error rate can be effectively reduced, and the system performance can be improved.

[0177] In a possible implementation, the first device performs time clipping noise and amplitude clipping noise processing on the third signal according to the decision interference cancellation algorithm, including: the first device performs QAM (Quadrature Amplitude Modulation) decision processing on the third signal based on water-filling parameters to obtain a decision QAM signal; the first device generates a DMT (Discrete Multi-Tone) signal by performing inverse Fourier transform processing on the decision QAM signal; the first device performs time clipping and amplitude clipping processing on the DMT signal based on clipping parameters to obtain a fourth signal, the fourth signal including time clipping noise and amplitude clipping noise; and the first device obtains a first QAM signal from which clipping noise is removed based on the fourth signal, the decision QAM signal, and the third signal.

[0178] For example, the implementation process of the first-stage decision interference cancellation algorithm is as follows: first, the receiving end demultiplexes the DMT signal by using FFT to obtain a recovered QAM signal S1 (an example of the third signal); then, the QAM signal S1 is subjected to QAM decision according to water-filling parameters provided by the transmitting end to obtain a decision QAM signal S2 (an example of the decision QAM signal); finally, the decision QAM signal S2 is input into a clipping noise reconstruction module for processing to obtain a QAM signal S4 from which clipping noise is removed (an example of the first QAM signal from which clipping noise is removed).

[0179] It should be noted that the QAM signal S4 from which clipping noise is removed can continue to be iteratively calculated in the first-stage interference cancellation algorithm. With an increase in the number of iterations, the QAM signal S4 from which clipping noise is removed is more accurate. When the number of iterations increases to a certain number, the accuracy of the QAM signal S4 from which clipping noise is removed no longer improves. That is, when the accuracy of the QAM signal S4 from which clipping noise is removed reaches a certain threshold, for example, 99%, the second-stage coding-aided interference cancellation algorithm can be entered.

[0180] The clipping noise reconstruction module mainly includes IFFT, time-amplitude clipping, and FFT. In the clipping noise reconstruction module, the specific implementation steps include:

[0181] First, the decision QAM signal S2 generates a DMT signal by using IFFT; the DMT signal is subjected to time-amplitude clipping according to clipping parameters provided by the transmitting end; a QAM signal S3 carrying clipping noise is recovered by using FFT (an example of the fourth signal); then, the QAM signal S3 carrying clipping noise is subtracted from the decision QAM signal S2 to obtain estimated clipping noise N1; finally, the recovered QAM signal S1 is subtracted from the estimated clipping noise N1 to obtain the QAM signal S4 from which clipping noise is removed.

[0182] In another possible implementation, the first device performs time clipping noise and amplitude clipping noise processing on the third signal according to the coded auxiliary interference cancellation algorithm, including: the first device performs QAM demapping processing on the first QAM signal without clipping noise to generate a second bit sequence; the first device performs de-interleaving and channel decoding processing on the second bit sequence to generate a third bit sequence; and the first device performs time clipping noise and amplitude clipping noise processing on the third bit sequence to obtain a second QAM signal without clipping noise.

[0183] In another possible implementation, the first device performs time clipping noise and amplitude clipping noise processing on the third bit sequence to obtain a second QAM signal without clipping noise, including: the first device performs channel coding and interleaving processing on the third bit sequence to generate a discrete multi-tone signal; the first device performs QAM mapping processing on the discrete multi-tone signal to obtain a fifth signal; the first device performs time clipping and amplitude clipping processing on the fifth signal to obtain a sixth signal, the sixth signal including time clipping noise and amplitude clipping noise; and the first device obtains the second QAM signal without clipping noise based on the sixth signal, the decision QAM signal and the fifth signal.

[0184] For example, the implementation process of the second-level coded auxiliary interference cancellation algorithm is as follows: first, the receiving end demultiplexes the DMT signal through FFT to obtain the recovered QAM signal S1; then, the QAM signal S4 without clipping noise output by the first-level decision interference cancellation algorithm is subjected to QAM demapping processing to obtain a bit sequence B1 (i.e., an example of the second bit sequence); and the bit sequence B1 is subjected to error correction through de-interleaving and channel decoding to obtain an error-corrected bit sequence B2 (i.e., an example of the third bit sequence). The error bit ratio of B2 is greatly reduced compared with B1, and the accurate bit sequence B2 is input into the clipping noise reconstruction module for processing to obtain the QAM signal S7 without clipping noise.

[0185] The clipping noise reconstruction module mainly includes channel coding, interleaving, QAM mapping, IFFT, time-amplitude clipping and FFT. In the clipping noise reconstruction module, the specific implementation steps include:

[0186] First, the bit sequence B2 is processed by channel coding and interleaving, and then QAM mapping is performed to obtain a QAM signal S5 without clipping noise; the QAM signal S5 is processed by IFFT to generate a DMT signal; the DMT signal is processed by time-amplitude clipping according to the clipping parameters provided by the transmitting end; the QAM signal S6 carrying clipping noise is recovered by FFT; then, the QAM signal S6 carrying clipping noise is subtracted from the QAM signal S5 to obtain an estimated clipping noise N2; finally, the recovered QAM signal S1 is subtracted from the estimated clipping noise N2 to obtain a QAM signal S7 without clipping noise (i.e., an example of a second QAM signal without clipping noise).

[0187] It should be understood that the meaning of channel coding is to add redundant bit information so that a large number of errors in a continuous symbol caused by channel influence can be found and corrected at the receiving end. Due to the limitation of the coding length, the coding method cannot achieve the function of error correction, and the commonly used method is interleaving. Interleaving is essentially a process of "disturbing" the data sequence, and the "disturbing" is actually rearranging in a certain artificial way. Interleaving is mainly completed by an interleaver. Its inverse process is deinterleaving, which restores the rearranged sequence to the original sequence order. It can be understood that after interleaving, a large number of continuous errors that may occur are dispersed into random errors, and the random errors can be solved by coding. That is, channel coding and interleaving, channel decoding and deinterleaving can greatly improve the error correction capability of the system.

[0188] It should be understood that based on the error correction capability of the bit sequence by channel coding, the estimated clipping noise N2 in the second-stage interference cancellation algorithm is more accurate than the estimated clipping noise N1 in the first-stage interference cancellation algorithm. When the bit error rate of the error-corrected bit sequence B2 is equal to the first threshold, for example, 99%, it indicates that the estimated clipping noise N2 is completely accurate, and the QAM signal S7 is completely free of clipping noise.

[0189] Exemplarily, the QAM signal S7 without clipping noise is processed by channel decoding to recover the first bit sequence.

[0190] Optionally, for the continuous interference cancellation algorithm of time clipping, a bit sequence #1 of the same length can be pre-set at the receiving end, and then the signal is received.

[0191] Exemplarily, the bit sequence #1 can be an all-0 sequence, for example, 000.

[0192] Optionally, the bit sequence #1 can also be a Gaussian distributed random sequence, which is not limited in the present application.

[0193] In this implementation, the necessary steps of the successive interference cancellation algorithm for time clipping can be completed with lower complexity.

[0194] It should be understood that the two interference cancellation algorithms provided above are only illustrative and should not constitute any limitation on the technical solutions of the present application.

[0195] A possible implementation is that when the receiving end performs channel decoding on the signal, an incomplete decoding manner can be used to reduce the number of decoding iterations.

[0196] It should be noted that the full decoding in the embodiments of the present application mainly refers to that in the S5 signal calculation process of the second-stage interference cancellation algorithm (i.e., the coded auxiliary interference cancellation algorithm), the decoding module needs to be iterated for several times to recover the error-free signal. The partial decoding refers to that when the BER of the system is good, the error-free state can be recovered by using only part of the iterations, so that the operation complexity and the time delay can be reduced.

[0197] It should be understood that the lower the signal-to-noise ratio of the channel is, the higher the bit error rate is, and the worse the user experience is.

[0198] Figure 5 is an example schematic diagram of an implementation of a partial decoding module applicable to the present application. As shown in Figure 5 , an input bit sequence is input and decoding iteration processing is performed until a correct bit sequence is output. After the ith iteration, it can be judged whether the output bit sequence is an error bit. When the bit error rate of the decoding output bit sequence is lower than a certain threshold, the decoding bit sequence can be output without completing all iteration times.

[0199] For example, it is assumed that 10 decoding iteration operations are required to completely correctly output the bit sequence, and after the 8th decoding iteration processing, the bit error rate of the output bit sequence is 2%, which is lower than the set threshold of 5%. Therefore, the receiving end can end the iteration decoding process and output the decoding bit sequence.

[0200] In this implementation, while maintaining certain performance requirements, the iteration number of channel decoding is reduced by simplifying the algorithm flow of the receiving end, thereby reducing the decoding complexity and power consumption of the receiving end.

[0201] Figure 6 is an example schematic diagram of a signal processing flow applicable to the present application. As shown in Figure 6 , at the transmitting end, the bit sequence is generated, channel coding is performed, the bit and power are water-filled for QAM mapping, the inverse fast Fourier transform (IFFT) is used to generate an orthogonal frequency division multiplexing signal, the generated orthogonal frequency division multiplexing signal is time-amplitude clipped, and finally the digital-to-analog converter generates an electrical orthogonal frequency division multiplexing signal.

[0202] At the receiving end, the electrical signal is firstly converted into a digital signal by an analog-to-digital converter, and then subjected to fast Fourier transform (FFT) and channel equalization to obtain a QAM signal carrying time-amplitude clipping noise, and the time-amplitude clipping noise is processed according to a successive interference cancellation algorithm, and finally channel decoding is performed to recover the bit sequence.

[0203] Figure 7 is an example of a calculation result of the two-stage interference cancellation algorithm according to the present application. As shown in Figure 7 , the horizontal coordinate is received optical power (ROP) and the vertical coordinate is bit error rate (BER). The interference cancellation algorithm not only improves the performance by about 2 dB near the FEC threshold, but also alleviates the error flatness problem at a high ROP.

[0204] In summary, in the technical solution of the present application, the transmitting end can overcome the influence of bandwidth limitation and peak power limitation on system performance by simultaneously performing time clipping and amplitude clipping on the signal, and the receiving end can reduce the interference introduced by time clipping and amplitude clipping by processing the time-amplitude clipping noise through an interference cancellation algorithm, thereby achieving the purpose of recovering the signal. In addition, according to the signal reception performance, a suitable algorithm combination can be selected for interference cancellation to achieve a balance between performance and complexity and ensure system performance.

[0205] The above describes in detail the embodiments of the signal processing method of the present application in combination with Figures 1 to 7 , and the following will describe in detail the embodiments of the signal processing device of the present application in combination with Figure 8 and Figure 9 . It should be understood that the description of the device embodiments corresponds to the description of the method embodiments, and therefore, the parts not described in detail can be referred to the foregoing method embodiments.

[0206] Figure 8 is an example of a device for signal processing provided by an embodiment of the present application. As shown in Figure 8 , the device 1000 can include a processing unit 1100 and a transceiver unit 1200.

[0207] Optionally, the device 1000 can correspond to the first device (e.g., the receiving end) in the foregoing method embodiments, or be a component (such as a circuit, a chip, or a chip system, etc.) configured in the first device.

[0208] For example, the transceiver unit 1200 is configured to receive, by the first device, a second signal from a second device, the second signal being generated based on time clipping and amplitude clipping of a first signal, the first signal being generated based on QAM mapping of a first bit sequence.

[0209] The processing unit 1100 is configured to perform QAM demapping processing on the second signal by the first device to obtain a third signal, and the third signal comprises time clipping noise and amplitude clipping noise.

[0210] The processing unit 1100 is further configured to perform time clipping noise and amplitude clipping noise processing on the third signal by the first device according to a successive interference cancellation algorithm to recover the first bit sequence.

[0211] It should be understood that the apparatus 1000 can correspond to the first device in the method according to the embodiments of the present application, and the apparatus 1000 can include units for performing the method performed by the first device in the method according to the embodiments of the present application. In addition, each unit in the apparatus 1000 and the other operations and / or functions described above are respectively configured to implement the corresponding flow of the method according to the embodiments of the present application.

[0212] It should be further understood that when the apparatus 1000 is the first device, the transceiver unit 1200 in the apparatus 1000 can be implemented by a transceiver, for example, can correspond to the transceiver 2020 in the apparatus 2000 shown in FIG. 2. Figure 9 The processing unit 1100 in the apparatus 1000 can be implemented by at least one processor, for example, can correspond to the processor 2010 in the apparatus 2000 shown in FIG. 2. Figure 9

[0213] It should be further understood that when the apparatus 1000 is a chip or a chip system configured in the first device, the transceiver unit 1200 in the apparatus 1000 can be implemented by an input / output interface, a circuit, etc., and the processing unit 1100 in the apparatus 1000 can be implemented by a processor, a microprocessor or an integrated circuit, etc. integrated on the chip or the chip system.

[0214] Optionally, the apparatus 1000 can correspond to the second device (for example, the transmitting end) in the above method embodiments, or a component (such as a circuit, a chip or a chip system, etc.) configured in the second device.

[0215] For example, the processing unit 1100 is configured to generate the first bit sequence by the second device.

[0216] The processing unit 1100 is further configured to perform QAM mapping processing on the first bit sequence by the second device to generate the first signal.

[0217] The processing unit 1100 is further configured to perform time clipping and amplitude clipping processing on the first signal by the second device to obtain the second signal.

[0218] The transceiver unit 1200 is configured to send the second signal to the first device by the second device.

[0219] ​It should be understood that the device 1000 may correspond to a second device in the method according to the embodiments of this application, and the device 1000 may include units for performing the method executed by the second device in the method of the embodiments of this application. Furthermore, each unit in the device 1000 and the other operations and / or functions described above are respectively for implementing the corresponding processes of the method of the embodiments of this application.

[0220] It should also be understood that when the device 1000 is a second device, the transceiver unit 1200 in the device 1000 can be implemented by a transceiver, for example, it can correspond to Figure 9 The transceiver 2020 in the device 2000 shown in the figure, and the processing unit 1100 in the device 1000 can be implemented by at least one processor, for example, corresponding to Figure 9 The processor 2010 in the device 2000 shown in the figure.

[0221] It should also be understood that when the device 1000 is a chip or chip system configured in the second device, the transceiver unit 1200 in the device 1000 can be implemented through input / output interfaces, circuits, etc., and the processing unit 1100 in the device 1000 can be implemented through a processor, microprocessor, or integrated circuit integrated on the chip or chip system.

[0222] Figure 9 This is another schematic diagram of the signal processing apparatus provided in the embodiments of this application. For example... Figure 9 As shown, the device 2000 includes a processor 2010, a transceiver 2020, and a memory 2030. The processor 2010, transceiver 2020, and memory 2030 communicate with each other via an internal connection. The memory 2030 stores instructions, and the processor 2010 executes the instructions stored in the memory 2030 to control the transceiver 2020 to transmit and / or receive signals.

[0223] It should be understood that the device 2000 may correspond to the first device / second device in the above method embodiments, and may be used to execute the various steps and / or processes executed by the first device / second device in the above method embodiments. Optionally, the memory 2030 may include read-only memory and random access memory, and provide instructions and data to the processor. A portion of the memory may also include non-volatile random access memory. The memory 2030 may be a separate device or integrated into the processor 2010. The processor 2010 may be used to execute instructions stored in the memory 2030, and when the processor 2010 executes instructions stored in the memory, the processor 2010 is used to execute the various steps and / or processes of the above method embodiments corresponding to the first device / second device.

[0224] Optionally, the apparatus 2000 is the first device in the previous embodiments.

[0225] The transceiver 2020 is configured to receive, by the first device, a second signal from a second device, the second signal being generated based on time clipping and amplitude clipping of the first signal, the first signal being generated based on QAM mapping of the first bit sequence.

[0226] The processor 2010 is configured to perform, by the first device, QAM demapping processing on the second signal to obtain a third signal, the third signal comprising time clipping noise and amplitude clipping noise.

[0227] The processor 2010 is further configured to perform, by the first device, time clipping noise and amplitude clipping noise processing on the third signal according to a successive interference cancellation algorithm to recover the first bit sequence.

[0228] Optionally, the apparatus 2000 is the second device in the previous embodiments.

[0229] The processor 2010 is configured to generate, by the second device, the first bit sequence.

[0230] The processor 2010 is further configured to perform, by the second device, QAM mapping processing on the first bit sequence to generate the first signal.

[0231] The processor 2010 is further configured to perform, by the second device, time clipping and amplitude clipping processing on the first signal to obtain the second signal.

[0232] The transceiver 2020 is configured to send, by the second device, the second signal to the first device.

[0233] The transceiver 2020 can include a transmitter and a receiver. The processor 2010 and the memory 2030 and the transceiver 2020 can be devices integrated on different chips. For example, the processor 2010 and the memory 2030 can be integrated on a baseband chip, and the transceiver 2020 can be integrated on a radio frequency chip. The processor 2010 and the memory 2030 and the transceiver 2020 can also be devices integrated on the same chip. The present application does not make any limitations in this regard.

[0234] Optionally, the apparatus 2000 is a component, such as a circuit, a chip, a chip system, etc., configured in the first device / second device.

[0235] The transceiver 2020 can also be a communication interface, such as an input / output interface, a circuit, etc. The transceiver 2020, the processor 2010 and the memory 2030 can be integrated on the same chip, such as a baseband chip.

[0236] It should be understood that the specific examples in the embodiments of the present application are only to help those skilled in the art better understand the technical solutions of the present application, and the above specific implementation manners can be considered as the optimal implementation manners of the present application, but not to limit the scope of the embodiments of the present application.

[0237] Those skilled in the art can clearly understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software manner depends on the specific application and design constraints of the technical solutions. Those skilled in the art can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0238] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0239] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the above-described device embodiments are only schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0240] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiments of the present application.

[0241] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit.

[0242] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the parts that contribute to the prior art or parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0243] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of signal processing, characterized by, The method is applied to a discrete multi-tone system, and the method comprises the following steps: A first device receives a second signal from a second device, the second signal being generated by time clipping and amplitude clipping based on a first signal, the first signal being generated by quadrature amplitude modulation (QAM) mapping based on a first bit sequence; The first device performs QAM demapping processing on the second signal to obtain a third signal, the third signal comprising time clipping noise and amplitude clipping noise; The first device performs time clipping noise and amplitude clipping noise processing on the third signal according to a successive interference cancellation algorithm to recover the first bit sequence.

2. The method of claim 1, wherein, The successive interference cancellation algorithm comprises a decision interference cancellation algorithm and / or a coded aided interference cancellation algorithm.

3. The method of claim 2, wherein, The first device performs time clipping noise and amplitude clipping noise processing on the third signal according to the successive interference cancellation algorithm, comprising: When the bit error rate of the discrete multi-tone system is less than a first threshold, the first device performs time clipping noise and amplitude clipping noise processing on the third signal according to the decision interference cancellation algorithm; or, When the bit error rate of the discrete multi-tone system is greater than or equal to the first threshold and less than or equal to a second threshold, the first device performs time clipping noise and amplitude clipping noise processing on the third signal according to a combined algorithm of the decision interference cancellation algorithm and the coded aided interference cancellation algorithm; or, When the bit error rate of the discrete multi-tone system is greater than the second threshold, the first device performs time clipping noise and amplitude clipping noise processing on the third signal according to the coded aided interference cancellation algorithm; Wherein, the first threshold is less than the second threshold.

4. The method of claim 3, wherein, The first device performs time clipping noise and amplitude clipping noise processing on the third signal according to the decision interference cancellation algorithm, comprising: The first device performs QAM decision processing on the third signal based on a water-filling parameter to obtain a decision QAM signal; The first device performs time clipping and amplitude clipping processing on the decision QAM signal to obtain a first QAM signal with clipping noise removed.

5. The method of claim 4, wherein, The first device performs time clipping and amplitude clipping processing on the decision QAM signal to obtain a first QAM signal with clipping noise removed, comprising: The first device generates a first discrete multi-tone signal after inverse Fourier transform processing of the decision QAM signal; The first device performs time clipping and amplitude clipping on the first discrete multi-tone signal based on a clipping parameter, and performs Fourier transform processing to obtain a fourth signal, the fourth signal comprising time clipping noise and amplitude clipping noise; The first device obtains the first QAM signal with clipping noise removed based on the fourth signal, the decision QAM signal and the third signal.

6. The method of claim 3, wherein, The first device performs time clipping noise and amplitude clipping noise processing on the third signal according to the coded aided interference cancellation algorithm, comprising: The first device performs QAM demapping processing on a first QAM signal without clipping noise to generate a second bit sequence, the first QAM signal without clipping noise being obtained by performing time clipping and amplitude clipping processing on a decision QAM signal, the decision QAM signal being obtained by performing QAM decision processing on the third signal based on a flooding parameter; The first device performs de-interleaving and channel decoding processing on the second bit sequence to generate a third bit sequence; The first device performs time clipping noise and amplitude clipping noise processing on the third bit sequence to obtain a second QAM signal without clipping noise.

7. The method of claim 6, wherein, The first device performs time clipping noise and amplitude clipping noise processing on the third bit sequence to obtain a second QAM signal without clipping noise, comprising: The first device performs channel coding and interleaving processing on the third bit sequence to generate a second discrete multi-tone signal; The first device performs QAM mapping processing on the second discrete multi-tone signal to obtain a fifth signal; The first device performs time clipping and amplitude clipping processing on the fifth signal to obtain a sixth signal, the sixth signal comprising time clipping noise and amplitude clipping noise; The first device obtains the second QAM signal without clipping noise based on the sixth signal, a decision QAM signal, and the fifth signal, the decision QAM signal being obtained by performing QAM decision processing on the third signal based on a flooding parameter.

8. The method according to claim 6 or 7, characterized in that, The bit error rate of the third bit sequence is less than a preset threshold.

9. A method of signal processing, characterized by, The method is applied to a discrete multi-tone system, and the method comprises: A second device generates a first bit sequence; The second device performs QAM mapping processing on the first bit sequence to generate a first signal; The second device performs time clipping and amplitude clipping processing on the first signal to obtain a second signal; The second device sends the second signal to a first device.

10. The method of claim 9, wherein, The second device performs time clipping and amplitude clipping processing on the first signal, comprising: The second device performs time clipping and amplitude clipping processing on the first signal according to a time clipping ratio and an amplitude clipping ratio, respectively.

11. The method of claim 10, wherein: The time clipping ratio a satisfies: a = (T-Tc) / T, and the amplitude clipping ratio b satisfies: b = A^2 / σ^2; Wherein, T is a period of the first signal in the time domain, Tc is a time of the first signal being clipped in the time domain, A is a maximum amplitude of the first signal after being clipped, and σ is a root mean square value of the first signal.

12. The method according to any one of claims 9 to 11, characterized in that, The second device performs QAM mapping processing on the first bit sequence, comprising: The second device performs QAM mapping processing on the first bit sequence according to a power and bit allocation algorithm based on a flooding principle.

13. An apparatus for signal processing, characterized by The method is applied to a discrete multi-tone system, and the method comprises: A transceiver unit configured to receive, by a first device, a second signal from a second device, the second signal being generated by performing time clipping and amplitude clipping on a first signal, the first signal being generated by performing QAM mapping on a first bit sequence; The processing unit is used for the first device to perform QAM demapping processing on the second signal to obtain a third signal, the third signal including time clipping noise and amplitude clipping noise; The processing unit is further configured to perform time-clipping noise and amplitude-clipping noise processing on the third signal by the first device according to a continuous interference cancellation algorithm, so as to recover the first bit sequence.

14. The apparatus of claim 13, wherein, The continuous interference cancellation algorithm includes a decision interference cancellation algorithm and / or a coding-assisted interference cancellation algorithm.

15. The apparatus of claim 14, wherein, Applied to discrete multitone systems, the processing unit is further used for: When the bit error rate of the discrete multi-tone system is less than the first threshold, the first device performs time-clipping noise and amplitude-clipping noise processing on the third signal according to the decision interference cancellation algorithm. or, When the bit error rate of the discrete multi-tone system is greater than or equal to the first threshold and less than or equal to the second threshold, the first device performs time-clipping noise and amplitude-clipping noise processing on the third signal according to the combination of the decision interference cancellation algorithm and the coding-assisted interference cancellation algorithm. or, When the bit error rate of the discrete multi-tone system is greater than the second threshold, the first device performs time-clipping noise and amplitude-clipping noise processing on the third signal according to the coding-assisted interference cancellation algorithm. Wherein, the first threshold is less than the second threshold.

16. The apparatus of claim 15, wherein, The processing unit is further configured to: The first device performs QAM decision processing on the third signal based on the water injection parameters to obtain a decision QAM signal; The first device performs time clipping and amplitude clipping processing on the decision QAM signal based on clipping parameters to obtain a first QAM signal with clipping noise removed.

17. The apparatus of claim 16, wherein, The processing unit is further configured to: The first device processes the decision QAM signal through an inverse Fourier transform to generate a first discrete multitone signal; The first device performs time clipping and amplitude clipping on the first discrete polyphonic signal based on clipping parameters, and performs Fourier transform processing to obtain a fourth signal, the fourth signal including time clipping noise and amplitude clipping noise; The first device acquires the first QAM signal after removing clipping noise based on the fourth signal, the decision QAM signal, and the third signal.

18. The apparatus of claim 15, wherein, The processing unit is further configured to: The first device performs QAM demapping processing on the first QAM signal with removed clipping noise to generate a second bit sequence. The first QAM signal with removed clipping noise is obtained by performing time clipping and amplitude clipping processing on the decision QAM signal. The decision QAM signal is obtained by performing QAM decision processing on the third signal based on the water injection parameters. The first device performs deinterleaving and channel decoding on the second bit sequence to generate a third bit sequence; The first device performs time-trimmed noise and amplitude-trimmed noise processing on the third bit sequence to obtain a second QAM signal with trimmed noise removed.

19. The apparatus of claim 18, wherein, The processing unit is further configured to: The first device performs channel coding and interleaving on the third bit sequence to generate a discrete multi-tone signal; The first device performs QAM mapping processing on the discrete multi-tone signal to obtain a fifth signal; The first device performs time clipping and amplitude clipping processing on the fifth signal to obtain a sixth signal, the sixth signal comprising time clipping noise and amplitude clipping noise; The first device obtains the second QAM signal from which clipping noise is removed based on the sixth signal, a decision QAM signal and the fifth signal, the decision QAM signal being obtained by performing QAM decision processing on the third signal based on a water-filling parameter.

20. The apparatus of claim 18 or 19, wherein, The error rate of the third bit sequence is less than a preset threshold.

21. An apparatus for signal processing, characterized by Applied to a discrete multi-tone system, comprising: A processing unit configured to generate, by a second device, a first bit sequence; The processing unit is further configured to perform, by the second device, QAM mapping processing on the first bit sequence to generate a first signal; The processing unit is further configured to perform, by the second device, time clipping and amplitude clipping processing on the first signal to obtain a second signal; A transceiving unit configured to transmit, by the second device, the second signal to a first device.

22. The apparatus of claim 21, wherein, The processing unit is further configured to: The second device performs time clipping and amplitude clipping processing on the first signal according to a time clipping ratio and an amplitude clipping ratio, respectively.

23. The apparatus of claim 22, wherein, The time clipping ratio a satisfies: a = (T-Tc) / T, and the amplitude clipping ratio b satisfies: b = A^2 / σ^2; Wherein, T is a period of the first signal in the time domain, Tc is a time during which the first signal is clipped in the time domain, A is a maximum amplitude of the first signal after clipping, and σ is a root mean square value of the first signal.

24. The apparatus of any one of claims 21-23, wherein, The processing unit is further configured to: The second device performs QAM mapping processing on the first bit sequence according to a power and bit allocation algorithm based on a water-filling principle.

25. A communications device, characterized by Comprising a processor and an interface circuit, the interface circuit being configured to receive signals from other communication devices outside the communication device and transmit the signals to the processor or send signals from the processor to other communication devices outside the communication device, the processor being configured to implement the method of any one of claims 1 to 12 through a logic circuit or by executing code instructions.

26. A communication system, characterized by Comprising: The apparatus of any one of claims 13 to 24 or 25.

27. A chip, characterized by Comprising: A processor configured to call and run a computer program from a memory, so that a communication device in which the chip is installed performs the method of any one of claims 1 to 12.

28. A computer storage medium, comprising, The computer storage medium stores computer instructions, and the instructions, when executed on a computer, cause the computer to perform the method of any one of claims 1 to 12.

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