Signal processing method and related device

Abstract

The embodiment of the invention discloses a signal processing method and a related device. The signal processing method can be applied to an optical communication scene. The method provided by the embodiment of the invention comprises the following steps: a sending end upsets the polarity of a part of symbols in a first modulation signal to obtain a second modulation signal, so that the absolute value of the sum of the values of all the symbols in the second modulation signal is smaller than the absolute value of the sum of the values of all the symbols in the first modulation signal. Therefore, the suppression of the low-frequency part power in the second modulation signal is realized, and the receiving end can carry out direct current removal processing on the signal to resist the influence of low-frequency noise in a channel on the transmission performance. And the receiving end carries out inverse transformation of power spectrum adjustment on the received signal according to the identification information, so that the original signal before the sending end carries out the power spectrum adjustment is recovered and obtained.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical communications, and in particular, to a signal processing method and related devices. Background Art

[0002] In the actual deployment of optical communication systems, the damage effect from the channel will cause the signal quality to deteriorate, causing the signal bit error rate to increase significantly, thus limiting the transmission performance of the optical communication system. Among them, for the application scenario of short-distance optical interconnection, the main solution is to combine intensity modulation direct detection (IMDD) with high-order modulation format, and high-order modulation signals are very susceptible to low-frequency noise, such as baseline drift. In addition, signal distortion caused by chromatic dispersion (CD) will also bring additional transmission costs, thereby limiting the transmission bandwidth of the system.

[0003] In order to reduce the impact of low-frequency noise and dispersion on optical transmission, the existing technology usually uses an equalization algorithm to perform channel compensation at the receiving end. However, only processing at the receiving end has problems such as high algorithm complexity and insufficient compensation capability in harsh environments. Summary of the invention

[0004] The embodiment of the present application provides a signal processing method and related devices. The transmitting end suppresses the power of the low-frequency part by flipping the polarity of some symbols in the modulated signal, which is beneficial to resisting the influence of low-frequency noise in the channel on the transmission performance.

[0005] In the first aspect, an embodiment of the present application provides a signal processing method, which is applied to a transmitting end. Specifically, the transmitting end obtains a first modulated signal, wherein the first modulated signal includes M first symbol sets, each first symbol set includes N symbols, and M and N are both integers greater than 1. For example, N is generally an integer multiple of 2. It should be understood that each first symbol set can also be referred to as a symbol block, and each symbol in a block can include multiple bits. Afterwards, the transmitting end flips the polarity of at least one symbol in at least one first symbol set of the first modulated signal to obtain a second modulated signal including M×N symbols. The absolute value of the sum of the values ​​of all symbols in the second modulated signal is less than the absolute value of the sum of the values ​​of all symbols in the first modulated signal. Then, the transmitting end sends the second modulated signal.

[0006] Furthermore, the sum of the values ​​of all symbols in the second modulated signal is less than or equal to the maximum value that a single symbol in the second modulated signal can take.

[0007] In this embodiment, the transmitting end obtains the second modulated signal by flipping the polarity of some symbols in the first modulated signal, so that the absolute value of the sum of the values ​​of all symbols in the second modulated signal is less than the absolute value of the sum of the values ​​of all symbols in the first modulated signal. This achieves the suppression of the power of the low-frequency part of the second modulated signal, which is beneficial for the receiving end to perform DC removal processing on the signal to resist the influence of low-frequency noise in the channel on the transmission performance. Compared with the channel compensation method at the receiving end, the processing method at the transmitting end is less complicated.

[0008] In some possible implementations, flipping the polarity of at least one symbol in at least one first symbol set of the first modulated signal includes: determining the value j corresponding to j when the sum of the values ​​of all symbols in the i-th second symbol set is the minimum value min The i-th second symbol set is obtained by flipping the polarity of all symbols after the j-th symbol in the i-th first symbol set, where 0≤i≤M-1, 0≤j≤N-2. min In this embodiment, the i-th first symbol set shares N-1 different polarity flipping modes to obtain the i-th second symbol set, and the polarity flipping mode that minimizes the sum of all symbol values ​​of the i-th second symbol set is selected, thereby improving the suppression effect of the power of the second modulated signal at low frequencies.

[0009] In some possible implementations, the method further includes: generating identification information, wherein the identification information is used to indicate the jth symbol in the i-th first symbol set. min It should be understood that the transmitting end will also send identification information to the receiving end, so that the receiving end can perform an inverse transformation of the power spectrum adjustment on the received signal according to the identification information, thereby recovering the original signal before the transmitting end performs the power spectrum adjustment.

[0010] In some possible implementations, the sum of the values ​​of all symbols in the second modulated signal is equal to 0, that is, the sum of the values ​​of all symbols in the second modulated signal is minimized, which is conducive to maximally suppressing the power of the second modulated signal at low frequencies and achieving better results.

[0011] In some possible implementations, flipping the polarity of at least one symbol in at least one first symbol set of the first modulated signal includes: obtaining the sum of the values ​​of all symbols in the i-th first symbol set, where 0≤i≤M-1. If the sum of the values ​​of all symbols in the i-th first symbol set is equal to 0, the polarities of all symbols in the i-th first symbol set remain unchanged. If the sum of the values ​​of all symbols in the i-th first symbol set is not equal to 0, flipping the polarity of at least one symbol in the i-th first symbol set to obtain the i-th second symbol set, and the sum of the values ​​of all symbols in the i-th second symbol set is equal to 0. In the above manner, the sum of the values ​​of each symbol set in the second modulated signal can be made to be 0, and the sum of the values ​​of all symbols in the second modulated signal is also equal to 0, which can compress the power spectrum of the low-frequency part of the second modulated signal to the greatest extent.

[0012] In some possible implementations, flipping the polarity of at least one symbol in the ith first symbol set to obtain the ith second symbol set includes: flipping the polarity of all symbols after the jth symbol in the ith first symbol set to obtain the ith second symbol set, 0≤j≤N-2. This implementation provides a specific implementation of flipping the polarity of symbols, which has better practical effects.

[0013] In some possible implementations, the method further includes: generating identification information, the identification information being used to indicate the position of the jth symbol in the i-th second symbol set. It should be understood that the transmitting end will also send the identification information to the receiving end, so that the receiving end performs an inverse transform of the power spectrum adjustment on the received signal according to the identification information, thereby recovering the original signal before the transmitting end performs the power spectrum adjustment.

[0014] In some possible implementations, before sending the second modulated signal, the method further includes: interleaving symbols in the second modulated signal. For the interleaved second modulated signal, in addition to compressing the low-frequency part of the power spectrum, other frequency points such as the intermediate frequency part or the high frequency part of the power spectrum can also be compressed.

[0015] In some possible implementations, the second modulation signal includes N shape symbol groups, each symbol group includes K symbols, M×N=N shape ×K,N shape is an integer greater than 1, and K is an integer greater than 1. The second modulated signal after interleaving is represented as: {the 0th symbol in the 0th symbol group, the 0th symbol in the 1st symbol group, ..., the Nth symbol shape The 0th symbol in the -1st symbol group, the 1st symbol in the 0th symbol group, the 1st symbol in the 1st symbol group, ..., the Nth symbol shape-1 symbol in the 1st symbol group, ..., the K-1th symbol in the 0th symbol group, the K-1th symbol in the 1st symbol group, ..., the Nth shape -1 symbol group}.

[0016] In some possible implementations, after acquiring the first modulated signal, before flipping the polarity of at least one symbol in at least one first symbol set of the first modulated signal to obtain a second modulated signal including M×N symbols, the method further includes: interleaving the symbols of each first symbol set in the first modulated signal. After flipping the polarity of at least one symbol in at least one first symbol set of the first modulated signal to obtain a second modulated signal including M×N symbols, before outputting the second modulated signal, the method further includes: deinterleaving the symbols in the second modulated signal according to the interleaving method. For the deinterleaved second modulated signal, in addition to compressing the low-frequency part of the power spectrum, compression of other frequency points such as the intermediate frequency part or the high frequency part of the power spectrum can also be achieved.

[0017] In some possible implementations, each first symbol set in the first modulated signal includes R consecutive symbol subsets, each symbol subset includes L symbols, N=R×L, R is an integer greater than 1, and L is an integer greater than 1. The first symbol set in the first modulated signal after interleaving is expressed as: {the 0th symbol in the 0th symbol subset, the 0th symbol in the 1st symbol subset, ..., the 0th symbol in the R-1th symbol subset, the 1st symbol in the 0th symbol subset, the 1st symbol in the 1st symbol subset, ..., the 1st symbol in the R-1th symbol subset, ..., the L-1th symbol in the 0th symbol subset, the L-1th symbol in the 1st symbol subset, ..., the L-1th symbol in the R-1th symbol subset}.

[0018] In the second aspect, an embodiment of the present application provides a signal processing method, which is applied to a receiving end. Specifically, the receiving end receives a first signal and identification information sent by the transmitting end after channel transmission. Among them, the first signal includes the signal sent by the transmitting end and the interference in the channel transmission. Afterwards, the first signal is subjected to DC removal processing to obtain a second signal, and the second signal can be regarded as a signal sent by the transmitting end. Among them, the second signal includes M symbol sets, each symbol set includes N symbols, M is an integer greater than 1, and N is an integer greater than 1. The identification information is used to indicate the polarity reversal of the symbols in each symbol set. Furthermore, the polarity of at least one symbol in at least one symbol set is reversed according to the identification information to obtain a third signal including M×N symbols to restore the original signal of the transmitting end.

[0019] In this embodiment, the receiving end performs DC removal processing on the signal to resist low-frequency noise in the channel. In addition, the receiving end performs an inverse transformation of power spectrum adjustment on the received signal according to the identification information, thereby recovering the original signal before the transmitting end performs power spectrum adjustment.

[0020] In some possible implementations, flipping the polarity of at least one symbol in at least one second symbol set according to the identification information includes: determining the jth symbol in the ith second symbol set according to the identification information, where 0≤i≤M-1, 0≤j≤N-2. Flipping the polarity of all symbols after the jth symbol in the ith second symbol set.

[0021] In a third aspect, an embodiment of the present application provides a chip, which includes a processor and a memory, the memory and the processor are interconnected via lines, instructions are stored in the memory, and the processor is used to execute the method described in any implementation method of the first aspect and the second aspect.

[0022] In a fourth aspect, an embodiment of the present application provides a transmitting end device, which includes: a processing unit and a transmitting unit. The processing unit is used to: obtain a first modulated signal, the first modulated signal includes M first symbol sets, each first symbol set includes N symbols, M is an integer greater than 1, and N is an integer greater than 1; flip the polarity of at least one symbol in at least one first symbol set of the first modulated signal to obtain a second modulated signal including M×N symbols, wherein the absolute value of the sum of the values ​​of all symbols in the second modulated signal is less than the absolute value of the sum of the values ​​of all symbols in the first modulated signal. The transmitting unit is used to: send the second modulated signal.

[0023] In some possible implementations, the processing unit is specifically configured to: determine the value j corresponding to the minimum value when the sum of the values ​​of all symbols in the i-th second symbol set is the minimum value. min , wherein the i-th second symbol set is obtained by flipping the polarity of all symbols after the j-th symbol in the i-th first symbol set, wherein 0≤i≤M-1, 0≤j≤N-2. min The polarity of all symbols after the first symbol is reversed.

[0024] In some possible implementations, the processing unit is further configured to: generate identification information, the identification information being used to indicate the jth symbol in the i-th first symbol set. min The position of a symbol.

[0025] In some possible implementations, the sum of the values ​​of all symbols in the second modulated signal is equal to 0.

[0026] In some possible implementations, the processing unit is specifically used to: obtain the sum of the values ​​of all symbols in the i-th first symbol set, where 0≤i≤M-1. If the sum of the values ​​of all symbols in the i-th first symbol set is equal to 0, the polarities of all symbols in the i-th first symbol set remain unchanged. If the sum of the values ​​of all symbols in the i-th first symbol set is not equal to 0, the polarity of at least one symbol in the i-th first symbol set is flipped to obtain the i-th second symbol set, and the sum of the values ​​of all symbols in the i-th second symbol set is equal to 0.

[0027] In some possible implementations, the processing unit is specifically configured to: flip the polarities of all symbols after the jth symbol in the i-th first symbol set to obtain the i-th second symbol set, 0≤j≤N-2.

[0028] In some possible implementations, the processing unit is further used to: generate identification information, where the identification information is used to indicate a position of the jth symbol in the i-th second symbol set.

[0029] In some possible implementations, before sending the second modulated signal, the processing unit is further configured to: interleave symbols in the second modulated signal.

[0030] In some possible implementations, the second modulation signal includes N shape symbol groups, each symbol group includes K symbols, M×N=N shape ×K,N shape is an integer greater than 1, and K is an integer greater than 1. The second modulated signal after interleaving is represented as: {the 0th symbol in the 0th symbol group, the 0th symbol in the 1st symbol group, ..., the Nth symbol shape The 0th symbol in the -1st symbol group, the 1st symbol in the 0th symbol group, the 1st symbol in the 1st symbol group, ..., the Nth symbol shape -1 symbol in the 1st symbol group, ..., the K-1th symbol in the 0th symbol group, the K-1th symbol in the 1st symbol group, ..., the Nth shape -1 symbol group}.

[0031] In some possible implementations, after acquiring the first modulated signal, before flipping the polarity of at least one symbol in at least one first symbol set of the first modulated signal to obtain a second modulated signal including M×N symbols, the processing unit is further used to: interleave the symbols of each first symbol set in the first modulated signal. After flipping the polarity of at least one symbol in at least one first symbol set of the first modulated signal to obtain a second modulated signal including M×N symbols, before sending the second modulated signal, the processing unit is further used to: deinterleave the symbols in the second modulated signal according to the interleaving method.

[0032] In some possible implementations, each first symbol set in the first modulated signal includes R consecutive symbol subsets, each symbol subset includes L symbols, N=R×L, R is an integer greater than 1, and L is an integer greater than 1. The first symbol set in the first modulated signal after interleaving is expressed as: {the 0th symbol in the 0th symbol subset, the 0th symbol in the 1st symbol subset, ..., the 0th symbol in the R-1th symbol subset, the 1st symbol in the 0th symbol subset, the 1st symbol in the 1st symbol subset, ..., the 1st symbol in the R-1th symbol subset, ..., the L-1th symbol in the 0th symbol subset, the L-1th symbol in the 1st symbol subset, ..., the L-1th symbol in the R-1th symbol subset}.

[0033] In a fifth aspect, an embodiment of the present application provides a receiving end device, which includes: a receiving unit and a processing unit. The receiving unit is used to: receive a first signal and identification information sent by the transmitting end through a channel. The processing unit is used to: perform DC removal processing on the first signal to obtain a second signal, the second signal includes M symbol sets, each symbol set includes N symbols, M is an integer greater than 1, N is an integer greater than 1, and the identification information is used to indicate the polarity reversal of the symbols in each symbol set. According to the identification information, the polarity of at least one symbol in at least one symbol set is reversed to obtain a third signal including M×N symbols.

[0034] In some possible implementations, the processing unit is specifically configured to: determine the jth symbol in the i-th second symbol set according to the identification information, where 0≤i≤M-1, 0≤j≤N-2, and flip the polarity of all symbols after the jth symbol in the i-th second symbol set.

[0035] In a sixth aspect, an embodiment of the present application provides a communication system, which includes a transmitting device as described in any implementation manner of the fourth aspect and a receiving device as described in any implementation manner of the fifth aspect.

[0036] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0037] The transmitting end obtains the second modulated signal by flipping the polarity of some symbols in the first modulated signal, so that the sum of the values ​​of all symbols in the second modulated signal is less than or equal to the maximum value that a single symbol in the second modulated signal can take. This suppresses the power of the low-frequency part of the second modulated signal, which is helpful to resist the influence of low-frequency noise in the channel on the transmission performance. Compared with the channel compensation method at the receiving end, the processing method at the transmitting end is less complicated. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of a communication system used in an embodiment of the present application;

[0039] FIG. 2( a ) is a schematic diagram of an implementation method of a transmitting end in an embodiment of the present application;

[0040] FIG. 2( b ) is a schematic diagram of two implementation methods of the sending end in an embodiment of the present application;

[0041] Figure 3 This is a schematic diagram of a first flow chart of a signal processing method in an embodiment of the present application;

[0042] Figure 4 A schematic diagram of compressing the power spectrum of the low-frequency part in an embodiment of the present application;

[0043] Figure 5 Schematic diagram of the corresponding relationship between OH and compression bandwidth in the embodiment of the present application;

[0044] Figure 6 are the positions of several possible compression frequency points in the power spectrum;

[0045] Figure 7 This is a second flow chart of the signal processing method in the embodiment of the present application;

[0046] Figure 8 A schematic diagram of a DC removal process performed by a receiving end in an embodiment of the present application;

[0047] Fig. 9 A schematic diagram of the structure of a sending end device in an embodiment of the present application;

[0048] Fig.10 This is another structural diagram of a sending end device in an embodiment of the present application;

[0049] Fig.11 A schematic diagram of the structure of a receiving device in an embodiment of the present application;

[0050] Fig.12 Another structural diagram of a receiving device in an embodiment of the present application. DETAILED DESCRIPTION

[0051] The embodiment of the present application provides a signal processing method and related devices. The transmitting end suppresses the power of the low-frequency part by flipping the polarity of some symbols in the modulated signal, which is beneficial to resisting the influence of low-frequency noise in the channel on the transmission performance.

[0052] It should be noted that the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, rather than to limit a specific order or precedence. It should be understood that the above terms can be interchanged where appropriate, so that the embodiments described in this application can be implemented in a sequence other than the content described in this application. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0053] Figure 1 Schematic diagram of a communication system used in the embodiment of the present application. Figure 1 As shown in the figure, at the transmitting end, the source provides the data stream to be sent. The encoder receives the data stream and encodes it. The codeword information obtained by encoding the check bits and information bits is sent to the transmitting end digital signal processing (DSP) processor for framing, and then transmitted through the channel to the receiving end. After the receiving end receives the distorted signal caused by noise or other damage in the channel, it is sent to the receiving end DSP processor for dispersion compensation, synchronization, phase recovery and other operations, and then decoded by the decoder to restore the original data and send it to the destination.

[0054] FIG2(a) is a schematic diagram of an implementation method of the transmitting end in an embodiment of the present application. As shown in FIG2(a), in a possible implementation, the transmitting end modulates the data stream to obtain a modulated signal. Then, the transmitting end performs power spectrum shaping encoding on the modulated signal, thereby compressing the power of the low-frequency part of the modulated signal to resist the influence of low-frequency noise. It should be understood that the transmitting end can also interleave the modulated signal that has undergone power spectrum shaping encoding to achieve power spectrum compression of multiple frequency points to resist the influence of power attenuation of multiple frequency points.

[0055] FIG2(b) is a schematic diagram of two implementation methods of the transmitting end in the embodiment of the present application. As shown in FIG2(b), in another possible implementation, the transmitting end modulates the data stream to obtain a modulated signal. After that, the transmitting end first interleaves the modulated signal, and then performs power spectrum shaping encoding on the interleaved modulated signal. Furthermore, the transmitting end deinterleaves the modulated signal after power spectrum shaping encoding according to the interleaving method to achieve power spectrum compression of multiple frequency points to resist the influence of power attenuation of multiple frequency points.

[0056] It should be understood that the present application does not limit the specific modulation method of the modulation signal. For example, the modulation method includes but is not limited to Not Return to Zero (NRZ) modulation and Multilevel Pulse Amplitude Modulation (PAMn), etc. Among them, PAMn modulation includes PAM2 modulation, PAM4 modulation or higher level PAM modulation.

[0057] It should be noted that the modulation and power spectrum shaping coding in Figure 2(a) and Figure 2(b) are necessary operations for compressing the power of the low-frequency part of the modulated signal. The interleaving in Figure 2(a) is an optional operation for achieving power spectrum compression of multiple frequency points. The interleaving and deinterleaving in Figure 2(b) are also optional operations, which are also used to achieve power spectrum compression of multiple frequency points.

[0058] The necessary operations in FIG. 2( a ) and FIG. 2( b ) are first introduced in detail below.

[0059] Figure 3 The first flow chart of the signal processing method in the embodiment of the present application is shown in FIG.

[0060] 101. Obtain a first modulated signal.

[0061] In this embodiment, the transmitting end modulates the data stream to obtain a first modulated signal. The first modulated signal includes M first symbol sets, each first symbol set includes N symbols, and M and N are both integers greater than 1. For example, N is usually an integer multiple of 2. It should be understood that each first symbol set can also be referred to as a symbol block, and each symbol in the block can include multiple bits.

[0062] 102. Perform power spectrum shaping encoding on the first modulated signal to obtain a second modulated signal.

[0063] Specifically, the transmitting end flips at least one symbol in at least one first symbol set of the first modulated signal to obtain a second modulated signal. It should be understood that which symbols in the first symbol set in the first modulated signal need to have their polarity flipped depending on the specific situation. Here, the first symbol set after the polarity of the symbol is flipped is referred to as the second symbol set. Among them, the second modulated signal still includes M×N symbols, that is, the second modulated signal includes both the second symbol set after the symbol polarity is flipped and the first symbol set without the symbol polarity flipped.

[0064] It should be noted that the transmitting end flips at least one symbol in at least one first symbol set so that the absolute value of the sum of the values ​​of all symbols in the second modulated signal is less than the absolute value of the sum of the values ​​of all symbols in the first modulated signal. Further, the sum of the values ​​of all symbols in the second modulated signal is less than or equal to the maximum value that a single symbol can take in the second modulated signal. It should be understood that the maximum value that a single symbol can take depends on the modulation format. For example, the maximum value that a single symbol can take in PAM4 modulation is +3, and the maximum value that a single symbol can take in PAM8 modulation is +7. In other words, the sum of the values ​​of all symbols in the second modulated signal is less than the highest level value of the second modulated signal. In this way, the power of the low-frequency part in the second modulated signal is reduced, which is conducive to processing at the receiving end to resist the influence of low-frequency noise. In one possible implementation, the sum of the values ​​of all symbols in the second modulated signal is equal to 0, and the power spectrum of the low-frequency part in the second modulated signal can be compressed to the greatest extent. In some possible scenarios, the value of each symbol can specifically correspond to the level value of the symbol modulation. As an example, take the symbol sequence {+1, +1, -1, -1, +1} obtained by NRZ modulation as an example, that is, the values ​​of the 5 symbols in the symbol sequence are +1, +1, -1, -1, +1 respectively, then the sum of the values ​​of the symbol sequence is +1. As another example, take the symbol sequence {+3, +1, -1, -3, +3} obtained by PAM4 modulation as an example, that is, the values ​​of the 5 symbols in the symbol sequence are +3, +1, -1, -3, +3 respectively, then the sum of the values ​​of the symbol sequence is +3. In other possible scenarios, the value of the symbol is a complex number, such as using Quadrature Phase Shift Keying (QPSK) or Quadrature Amplitude Modulation (QAM). Taking QPSK as an example, the value of each symbol is 1+1j, 1-1j, -1+1j, -1-1j. Assuming that the symbol sequence is 1+1j, 1-1j, -1+1j, -1-1j, 1+1j, then the sum of the values ​​of the symbol sequence is 1+1j, that is, the sum of the values ​​of the complex number is the result of adding the real part and the imaginary part of the complex number respectively.

[0065] The specific implementation method of power spectrum shaping coding is introduced below.

[0066] Take the i-th first symbol set as an example, where 0≤i≤M-1. The transmitter flips the polarity of all symbols after the j-th symbol in the i-th first symbol set to obtain the i-th second symbol set, where 0≤j≤N-2. That is, the transmitter determines the target symbol in the i-th first symbol set, recorded as the j-th symbol, and flips the polarity of all symbols after the target symbol. The target symbol can be any symbol from the 0th symbol to the N-2th symbol in the i-th first symbol set. Then, there are N-1 different symbol polarity flipping methods for the i-th first symbol set, and accordingly, the i-th first symbol set corresponds to N-1 second symbol sets with symbol polarity flipped. Furthermore, the sum of all symbol values ​​of each second symbol set in these N-1 second symbol sets is determined, and the second symbol set with the smallest sum of all symbol values ​​is selected. The target symbol corresponding to the second symbol set is recorded as j. min Therefore, what is finally obtained is the jth in the i-th first symbol set. min The i-th second symbol set after the polarities of all symbols after the i-th symbol are reversed.

[0067] It should be noted that if there are actually multiple different target symbols in the i-th first symbol set that can minimize the sum of the values ​​of all symbols after the polarity is flipped, one of the target symbols can be selected as the actual flip point according to the carrying method of the identification information. For example, if the identification information is interspersed at the beginning or end of each symbol set in the second modulation signal, try to select a target symbol located in the middle of the symbol set away from the beginning or end to avoid the appearance of long consecutive 0s or long consecutive 1s after the identification information is converted into a binary sequence. For another example, if the identification information is transmitted independently of the second modulation signal, you can select any one of the multiple target symbols.

[0068] In a possible scenario, in order to make the sum of the values ​​of all symbols in the second modulated signal equal to 0, it should be ensured that the sum of the values ​​of all symbols in each symbol set of the second modulated signal is equal to 0. Specifically, for the M first symbol sets in the first modulated signal, first determine whether the sum of the values ​​of each first symbol set is 0. Take the i-th first symbol set as an example, where 0≤i≤M-1. If the sum of the values ​​of all symbols in the i-th first symbol set is 0, the polarity of all symbols in the i-th first symbol set is maintained. If the sum of the values ​​of all symbols in the i-th first symbol set is not 0, the polarity of at least one symbol in the i-th first symbol set is flipped to obtain the i-th second symbol set, so that the sum of the values ​​of all symbols in the i-th second symbol set is 0. In this way, the sum of the values ​​of each symbol set in the second modulated signal is 0, and the sum of the values ​​of all symbols in the second modulated signal is also equal to 0, which can compress the power spectrum of the low-frequency part of the second modulated signal to the greatest extent.

[0069] As an example, the transmitting end reverses the polarity of all symbols after the jth symbol in the i-th first symbol set to obtain the i-th second symbol set, where 0≤j≤N-2. Specifically, first calculate the sum of the values ​​of all N symbols in the i-th first symbol set, which is recorded as Then, find the jth symbol in the i-th first symbol set, recorded as the Nth symbol in the first symbol set. b Symbols. Among them, the 0th symbol to the Nth symbol in the i-th first symbol set b The sum of the values ​​of the symbols is equal to half of the sum of the values ​​of all N symbols in the i-th first symbol set, that is, Therefore, the sum of the values ​​of the i-th second symbol set obtained by flipping the polarity of all symbols after the target symbol in the i-th first symbol set is equal to 0. Taking NRZ modulation as an example, the i-th first symbol set is expressed as {+1,-1,-1,...,+1,+1,-1,+1,-1,-1,...}, and its corresponding i-th second symbol set is expressed as {+1,-1,-1,...,+1,+1,+1,-1,+1,+1,...}. It should be noted that the transmitter can also select some symbols in the i-th first symbol set that need to flip polarity in other ways, as long as the sum of the values ​​of all N symbols in the i-th second symbol set is equal to 0. The specific implementation method is not limited here.

[0070] In another possible scenario, for the M first symbol sets in the first modulated signal, first determine whether the sum of the values ​​of each first symbol set is 0. If the sum of the values ​​of all symbols in a first symbol set is 0, the polarity of all symbols in the first symbol set is maintained. For other partial first symbol sets whose sum of values ​​is not 0, it is not strictly required that the sum of the values ​​of each second symbol set after the symbol polarity is flipped is equal to 0, as long as the sum of the values ​​of this part of the second symbol set as a whole is equal to 0, it can also ensure that the sum of the values ​​of all symbols in the second modulated signal is equal to 0. It should be understood that the present application does not limit the specific operation method, and several possible examples are introduced below. Taking the 10 second symbol sets obtained after the symbol polarity is flipped as an example, for example, let each two second symbol sets be a group to achieve complete positive and negative cancellation of the two second symbol sets, that is, the overall sum of the values ​​of each two second symbol sets as a group is equal to 0. For another example, let the overall sum of the values ​​of 5 second symbol sets and the overall sum of the values ​​of the other 5 second symbol sets achieve complete positive and negative cancellation.

[0071] Figure 4 Schematic diagram of compressing the power spectrum of the low-frequency part in the embodiment of the present application. Figure 4As shown in the figure, the horizontal axis represents frequency (in MHz), and the vertical axis represents power spectrum density (in dB). Taking PAM4 modulation as an example, each block includes 256 symbols. It can be seen that the second modulated signal after power spectrum shaping encoding realizes the compression of the power spectrum of the low-frequency part, and the 3dB bandwidth is 80MHz.

[0072] 103. Send a second modulated signal.

[0073] The second modulated signal sent by the transmitting end is transmitted to the receiving end through the channel.

[0074] It should be noted that in order for the receiving end to be able to recover the first modulated signal before the transmitting end performs power spectrum shaping encoding after removing DC, the transmitting end also needs to send identification information to the receiving end to indicate the polarity reversal of each symbol set in the second modulated signal. Then, the receiving end can flip the polarity of some symbols again according to the identification information to obtain the original modulated signal from the transmitting end. As an example, the transmitting end flips the polarity of all symbols after the target symbol in the i-th first symbol set, and the identification information is specifically used to indicate the position of the target symbol. It should be noted that the second modulated signal and the identification information can be sent to the receiving end together through the channel. Alternatively, the identification information can also be sent to the receiving end through other channels independently of the second modulated signal.

[0075] In one possible implementation, the identification information includes M indicator bits corresponding one-to-one to the M symbol sets in the second modulated signal, and each indicator bit is used to indicate the polarity reversal of the symbol in the corresponding symbol set. The M indicator bits can be interspersed in the M symbol sets of the second modulated signal. For example, each indicator bit is adjacent to the starting position of the symbol set to which it corresponds. For another example, each indicator bit is adjacent to the end position of the symbol set to which it corresponds. For another example, each indicator bit can also be inserted at any position in the symbol set corresponding thereto, which is not specifically limited here.

[0076] Figure 5 Schematic diagram of the corresponding relationship between OH and compressed bandwidth in the embodiment of the present application. It should be noted that the above identification information can also be called overhead (OH). Figure 5 As shown in the figure, the horizontal axis represents the proportion of OH in the block, and the vertical axis represents the compression bandwidth of the power spectrum (in MHz). b The corresponding relationship is: OH = log2N b / (log2N b +N b ). It can be seen that as OH increases, the power spectrum compression bandwidth of the signal becomes larger, and the suppression effect on low frequencies is better, but the redundant information will also increase accordingly.

[0077] The optional operations in FIG. 2( a ) and FIG. 2( b ) are first introduced in detail below.

[0078] In a possible scenario, as shown in FIG2(a), the transmitting end may also interleave the second modulated signal to reorder the symbols in the second modulated signal, thereby achieving power spectrum compression at multiple different frequency positions. That is, for the interleaved second modulated signal, in addition to compressing the low-frequency part of the power spectrum, other frequency points such as the intermediate frequency part or the high frequency part of the power spectrum can also be compressed. The following introduces a possible interleaving method. For example, the second modulated signal includes N shape symbol groups, each symbol group includes K symbols, M×N=N shape ×K,N shape is an integer greater than 1, and K is an integer greater than 1. It should be understood that the symbol group here is not equivalent to the block introduced above, and the N of the symbol group shape The second modulated signal after the interleaving is represented as: {the 0th symbol in the 0th symbol group, the 0th symbol in the 1st symbol group, ..., the Nth symbol shape The 0th symbol in the -1st symbol group, the 1st symbol in the 0th symbol group, the 1st symbol in the 1st symbol group, ..., the Nth symbol shape -1 symbol in the 1st symbol group, ..., the K-1th symbol in the 0th symbol group, the K-1th symbol in the 1st symbol group, ..., the Nth shape -1 symbol group}.

[0079] In another possible scenario, as shown in FIG2(b), before the transmitting end performs power spectrum shaping coding on the first modulated signal, the transmitting end first interleaves the first modulated signal to reorder the symbols in the first modulated signal. Next, the transmitting end performs power spectrum shaping coding on the interleaved first modulated signal. The specific implementation of power spectrum shaping coding can refer to the relevant introduction of step 102, which will not be repeated here. Furthermore, the transmitting end deinterleaves the second modulated signal obtained after power spectrum shaping coding, wherein deinterleaving can be regarded as the inverse processing operation of interleaving, and the corresponding deinterleaving operation is performed based on the interleaving rules to restore the original symbol order. It should be understood that for the second modulated signal after deinterleaving, in addition to the low-frequency part of the power spectrum being compressed, other frequency points such as the intermediate frequency part or the high frequency part of the power spectrum can also be compressed. A possible interleaving method is introduced below. For example, each first symbol set in the first modulated signal includes R continuous symbol subsets, each symbol subset includes L symbols, N=R×L, wherein R is an integer greater than 1, and L is an integer greater than 1. Then, the first symbol set in the first modulated signal after interleaving is expressed as: {the 0th symbol in the 0th symbol subset, the 0th symbol in the 1st symbol subset,…, the 0th symbol in the R-1th symbol subset, the 1st symbol in the 0th symbol subset, the 1st symbol in the 1st symbol subset,…, the 1st symbol in the R-1th symbol subset,…, the L-1th symbol in the 0th symbol subset, the L-1th symbol in the 1st symbol subset,…, the L-1th symbol in the R-1th symbol subset}.

[0080] It should be noted that, for the scenario shown in FIG. 2( a ), the power spectrum compression frequency corresponding to the second modulated signal output by the transmitter depends on N shape The following table 1 gives the value of N shape The power spectrum compression frequency points corresponding to several typical values, namely N shape The values ​​of include but are not limited to 2, 4, and 8. Figure 6 are the possible locations of several compression frequency points in the power spectrum. Figure 6 As shown, the horizontal axis represents frequency (in MHz), and the vertical axis represents power spectrum density (in dB). Figure 6 (a) shows N shape =2, the position of the compression frequency point in the power spectrum, Figure 6 (b) shows N shape =4, the position of the compression frequency point in the power spectrum, Figure 6 (c) shows N shape = 8. The compressed frequency points in the power spectrum in Table 1 are expressed as the relative positions of the compressed frequency points within the frequency coverage range of the power spectrum. Figure 6As shown, the frequency range of the power spectrum is 0MHz to 4×10 4 For example, a compression frequency point of 1 / 2 means that the compression frequency point is located in the middle of the frequency coverage range of the power spectrum, that is, 2×10 4 MHz. For another example, a compression frequency of 1 / 4 means that the compression frequency is located at 1 / 4 of the frequency coverage range of the power spectrum, that is, 1×10 4 MHz. For another example, the compression frequency point is 3 / 4, which means that the compression frequency point is located at 3 / 4 of the frequency coverage range of the power spectrum, that is, 3×10 4 MHz.

[0081] For the scenario shown in Figure 2(b), the power spectrum compression frequency point corresponding to the second modulated signal output by the transmitter depends on the value of L = N / R. That is, when the value of L is 2, 4, and 8, the compression frequency point position of the power spectrum is as follows: Figure 6 As shown in (a), (b) and (c).

[0082] Table 1

[0083] Serial number <![CDATA[N shape or L]]> Power spectrum compression frequency 1 2 0，1 2 4 0，1 / 2，1 3 8 0，1 / 4，1 / 2，3 / 4，1

[0084] From the above introduction, it can be seen that the transmitter obtains the second modulated signal by flipping the polarity of some symbols in the first modulated signal, so that the sum of the values ​​of all symbols in the second modulated signal is equal to 0. This can suppress the power of the low-frequency part of the second modulated signal, which is beneficial to resist the influence of low-frequency noise in the channel on the transmission performance. Compared with the channel compensation method at the receiving end, the processing method at the transmitter is less complicated.

[0085] The following is an introduction to the processing flow at the receiving end.

[0086] Figure 7 The second flow chart of the signal processing method in the embodiment of the present application is shown in FIG.

[0087] 201. Receive a first signal and identification information sent by a transmitting end and transmitted through a channel.

[0088] It should be noted that the first signal received by the receiving end includes the signal sent by the transmitting end and the interference in the channel transmission. Since the transmitting end flips the polarity of some symbols in the original signal before sending the signal, the identification information is used to indicate the polarity flipping of the symbols in the signal sent by the transmitting end, so that the receiving end can recover the original signal of the transmitting end according to the identification information.

[0089] 202. Perform DC removal processing on the first signal to obtain a second signal.

[0090] Figure 8 This is a schematic diagram of the DC removal process performed by the receiving end in the embodiment of the present application. It should be understood that there is low-frequency interference in the channel, and the power of the signal sent by the transmitting end at the low frequency is suppressed, so that the transmitted signal and the interference do not overlap in frequency. The receiving end can remove the interference through the DC removal process without causing damage to the signal from the transmitting end. In other words, the second signal obtained by the receiving end after the DC removal can be regarded as the signal sent by the transmitting end. Based on the above Figure 3 It can be seen from the relevant introduction of the illustrated embodiment that the second signal includes M symbol sets, each symbol set includes N symbols, M is an integer greater than 1, and N is an integer greater than 1.

[0091] 203. Reverse the polarity of at least one symbol in at least one symbol set according to the identification information to obtain a third signal.

[0092] The receiving end determines which symbols in which symbol sets in the second signal need to flip polarity according to the identification information, and then flips the polarity of these symbols, thereby restoring the modulated signal before the transmitting end performs power spectrum shaping encoding. In other words, the operation of step 203 can also be regarded as the inverse operation of the above step 102. The third signal can be regarded as the original signal before the transmitting end performs power spectrum shaping encoding.

[0093] As an example, the transmitting end adopts PAM4 modulation, and each symbol set in the second signal includes 256 symbols, and the corresponding indicator bit is inserted at the end of each symbol set. The receiving end determines the length of the indicator bit according to the size of the symbol set, that is, log2256=8. Taking the symbol sequence of the symbol set + indicator bit as […-3, 1, 3, -1, 3, 1, -3, 1, -3, 3, 1, -1…-3, 3, 3, -1, 3, -1, -3, 1] as an example, the indicator bit is represented by the last 8 symbols in the symbol sequence. The receiving end converts the indicator bit [-3, 3, 3, -1, 3, -1-3, 1] into binary information [01101001], whose decimal number is 105. Therefore, the receiving end flips the polarity of the 106th to 256th symbols in the symbol set, and the symbol set after the symbol polarity flip is expressed as […-3, 1, 3, -1, 3, 1, 3, -1, 3, -3, -1, 1…].

[0094] It should be noted that in some possible scenarios, as shown in FIG2(a), if the transmitter outputs an interleaved modulated signal, the receiver needs to perform a deinterleaving operation on the received modulated signal before performing DC removal processing.

[0095] Fig. 9 FIG. 1 is a schematic diagram of a structure of a transmitting end device in an embodiment of the present application. Fig. 9As shown, the transmitting end device includes: a processing unit 301 and a transmitting unit 302. The processing unit 301 is used to perform the operations of the above steps 101 and 102, and the transmitting unit 302 is used to perform the operation of the above step 103. Optionally, the processing unit 301 is also used to perform the interleaving operation shown in FIG2(a), or the processing unit 301 is also used to perform the interleaving operation and the deinterleaving operation shown in FIG2(a).

[0096] It should be understood that the transmitting end device provided by the present application can also be implemented in other ways. For example, the unit division in the above-mentioned device is only a logical functional division, and there may be other division methods in actual implementation, for example, multiple units or components can be combined or integrated into another system. In addition, the functional units in the various embodiments of the present application can be integrated into a processing unit, or they can be independent physical units, or two or more functional units can be integrated into a processing unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0097] Fig.10 FIG. 2 is another structural diagram of a transmitting end device in an embodiment of the present application. Fig.10 As shown, the transmitting end device includes a processor 401 and a transceiver 402. The processor 401 and the transceiver 402 are connected to each other through a line. Specifically, the transceiver 402 is used to perform signal transmission and reception operations, and the processor 401 is used to perform other operations except signal transmission and reception. In a possible implementation, the processor 401 may include the above Fig. 9 The processing unit 301 and the transceiver 402 shown include the above Fig. 9 The sending unit 302 is shown. Optionally, the sending end device may further include a memory 403, wherein the memory 403 is used to store program instructions and data.

[0098] Fig.11 FIG. 1 is a schematic diagram of a structure of a receiving device in an embodiment of the present application. Fig.11 As shown, the receiving end device includes: a receiving unit 501 and a processing unit 502. The receiving unit 501 is used to perform the operation of step 201, and the processing unit 502 is used to perform the operations of step 202 and step 203.

[0099] It should be understood that the receiving device provided by the present application can also be implemented in other ways. For example, the unit division in the above-mentioned device is only a logical functional division, and there may be other division methods in actual implementation, for example, multiple units or components can be combined or integrated into another system. In addition, the functional units in each embodiment of the present application can be integrated into a processing unit, or can be independent physical units, or two or more functional units can be integrated into a processing unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0100] Fig.12 FIG. 1 is another structural diagram of a receiving device in an embodiment of the present application. Fig.12 As shown, the receiving end device includes a processor 601 and a transceiver 602. The processor 601 and the transceiver 602 are connected to each other through a line. Specifically, the transceiver 602 is used to perform signal transmission and reception operations, and the processor 601 is used to perform other operations except signal transmission and reception. In a possible implementation, the processor 601 may include the above Fig.11 The processing unit 502 and the transceiver 602 shown include the above Fig.11 The receiving unit 501 is shown. Optionally, the receiving end device may further include a memory 603, wherein the memory 603 is used to store program instructions and data.

[0101] The embodiment of the present application also provides a chip. The chip integrates a circuit and one or more interfaces for implementing the functions of the above-mentioned processor 401 or processor 601. When the chip integrates a memory, the chip can complete the method steps of any one or more embodiments in the above-mentioned embodiments. When the chip does not integrate a memory, it can be connected to an external memory through an interface. The chip implements the actions performed by the sending end device or the receiving end device in the above-mentioned embodiment according to the program code stored in the external memory.

[0102] Finally, it should be noted that 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 who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A signal processing method, characterized in that: include: Acquire a first modulated signal, where the first modulated signal includes M first symbol sets, each of the first symbol sets includes N symbols, where M is an integer greater than 1, and N is an integer greater than 1; Flipping the polarity of at least one symbol in at least one of the first symbol sets of the first modulated signal to obtain a second modulated signal including M×N symbols, wherein an absolute value of the sum of values ​​of all symbols in the second modulated signal is less than an absolute value of the sum of values ​​of all symbols in the first modulated signal; The second modulated signal is transmitted.

2. The method according to claim 1, characterized in that Flipping the polarity of at least one symbol in at least one of the first symbol sets of the first modulated signal includes: Determine the value of j corresponding to the minimum value when the sum of the values ​​of all symbols in the i-th second symbol set is the minimum value min , wherein the i-th second symbol set is obtained by reversing the polarities of all symbols after the j-th symbol in the i-th first symbol set, wherein 0≤i≤M-1, 0≤j≤N-2; For the jth symbol in the i-th first symbol set min The polarity of all symbols after the first symbol is reversed.

3. The method according to claim 2, characterized in that The method further comprises: Generate identification information, the identification information is used to indicate the jth in the i-th first symbol set min The position of a symbol.

4. The method according to claim 1, characterized in that: The sum of values ​​of all symbols in the second modulated signal is equal to 0.

5. The method according to claim 4, characterized in that Flipping the polarity of at least one symbol in at least one of the first symbol sets of the first modulated signal includes: Obtain the sum of the values ​​of all symbols in the i-th first symbol set, where 0≤i≤M-1; If the sum of the values ​​of all symbols in the i-th first symbol set is equal to 0, the polarities of all symbols in the i-th first symbol set remain unchanged; If the sum of the values ​​of all symbols in the i-th first symbol set is not equal to 0, the polarity of at least one symbol in the i-th first symbol set is flipped to obtain the i-th second symbol set, and the sum of the values ​​of all symbols in the i-th second symbol set is equal to 0.

6. The method according to claim 5, characterized in that Flipping the polarity of at least one symbol in the i-th first symbol set to obtain the i-th second symbol set includes: The polarities of all symbols after the jth symbol in the i-th first symbol set are reversed to obtain the i-th second symbol set, 0≤j≤N-2.

7. The method according to claim 6, characterized in that The method further comprises: Generate identification information, where the identification information is used to indicate a position of the jth symbol in the i-th second symbol set.

8. The method according to any one of claims 1 to 7, characterized in that Before sending the second modulated signal, the method further includes: The symbols in the second modulated signal are interleaved.

9. The method according to claim 8, characterized in that The second modulation signal includes N shape symbol groups, each of which includes K symbols, M×N=N shape × K, N shape is an integer greater than 1, K is an integer greater than 1, and the second modulated signal after the interleaving is expressed as: {the 0th symbol in the 0th symbol group, the 0th symbol in the 1st symbol group, ..., the Nth shape The 0th symbol in the -1st symbol group, the 1st symbol in the 0th symbol group, the 1st symbol in the 1st symbol group, ..., the Nth symbol shape -1 symbol in the 1st symbol group, ..., the K-1th symbol in the 0th symbol group, the K-1th symbol in the 1st symbol group, ..., the Nth shape -1 symbol group}.

10. The method according to any one of claims 1 to 7, characterized in that After acquiring the first modulated signal, before flipping the polarity of at least one symbol in at least one of the first symbol sets of the first modulated signal to obtain a second modulated signal including M×N symbols, the method further includes: interleaving each symbol of the first symbol set in the first modulated signal; After flipping the polarity of at least one symbol in at least one of the first symbol sets of the first modulated signal to obtain a second modulated signal including M×N symbols, and before sending the second modulated signal, the method further includes: The symbols in the second modulated signal are deinterleaved according to the interleaving method.

11. The method according to claim 10, characterized in that Each first symbol set in the first modulated signal includes R consecutive symbol subsets, each of the symbol subsets includes L symbols, N=R×L, R is an integer greater than 1, and L is an integer greater than 1. The first symbol set in the first modulated signal after the interleaving is expressed as: {the 0th symbol in the 0th symbol subset, the 0th symbol in the 1st symbol subset,…, the 0th symbol in the R-1th symbol subset, the 1st symbol in the 0th symbol subset, the 1st symbol in the 1st symbol subset,…, the 1st symbol in the R-1th symbol subset,…, the L-1th symbol in the 0th symbol subset, the L-1th symbol in the 1st symbol subset,…, the L-1th symbol in the R-1th symbol subset}.

12. A signal processing method, characterized in that: include: Receiving a first signal and identification information transmitted through a channel and sent by a transmitting end; Performing DC removal processing on the first signal to obtain a second signal, the second signal including M symbol sets, each of the symbol sets including N symbols, M is an integer greater than 1, N is an integer greater than 1, and the identification information is used to indicate the polarity reversal of the symbols in each of the symbol sets; The polarity of at least one symbol in at least one of the symbol sets is flipped according to the identification information to obtain a third signal including M×N symbols.

13. The method according to claim 12, characterized in that Flipping the polarity of at least one symbol in at least one of the second symbol sets according to the identification information includes: Determine the jth symbol in the i-th second symbol set according to the identification information, where 0≤i≤M-1, 0≤j≤N-2; The polarities of all symbols after the jth symbol in the i-th second symbol set are reversed.

14. A chip, characterized in that: The chip includes a processor and a memory, wherein the memory and the processor are connected to each other via a line, instructions are stored in the memory, and the processor is used to execute the method according to any one of claims 1 to 13.

15. A transmitting end device, characterized in that: include: A processing unit and a sending unit; The processing unit is used to: obtain a first modulated signal, the first modulated signal includes M first symbol sets, each of the first symbol sets includes N symbols, M is an integer greater than 1, and N is an integer greater than 1; Flipping the polarity of at least one symbol in at least one of the first symbol sets of the first modulated signal to obtain a second modulated signal including M×N symbols, wherein an absolute value of the sum of values ​​of all symbols in the second modulated signal is less than an absolute value of the sum of values ​​of all symbols in the first modulated signal; The sending unit is used to: send the second modulated signal.

16. The transmitting end device according to claim 15, characterized in that: The processing unit is specifically used for: Determine the value of j corresponding to the minimum value when the sum of the values ​​of all symbols in the i-th second symbol set is the minimum value min , wherein the i-th second symbol set is obtained by reversing the polarities of all symbols after the j-th symbol in the i-th first symbol set, wherein 0≤i≤M-1, 0≤j≤N-2; For the jth symbol in the i-th first symbol set min The polarity of all symbols after the first symbol is reversed.

17. The transmitting end device according to claim 16, characterized in that: The processing unit is also used for: Generate identification information, the identification information is used to indicate the jth in the i-th first symbol set min The position of a symbol.

18. The transmitting end device according to claim 15, characterized in that: The sum of values ​​of all symbols in the second modulated signal is equal to 0.

19. The transmitting end device according to claim 18, characterized in that: The processing unit is specifically used for: Obtain the sum of the values ​​of all symbols in the i-th first symbol set, where 0≤i≤M-1; If the sum of the values ​​of all symbols in the i-th first symbol set is equal to 0, the polarities of all symbols in the i-th first symbol set remain unchanged; If the sum of the values ​​of all symbols in the i-th first symbol set is not equal to 0, the polarity of at least one symbol in the i-th first symbol set is flipped to obtain the i-th second symbol set, and the sum of the values ​​of all symbols in the i-th second symbol set is equal to 0.

20. The transmitting end device according to claim 19, characterized in that: The processing unit is specifically used for: The polarities of all symbols after the jth symbol in the i-th first symbol set are reversed to obtain the i-th second symbol set, 0≤j≤N-2.

21. The transmitting end device according to claim 20, characterized in that: The processing unit is also used for: Generate identification information, where the identification information is used to indicate a position of the jth symbol in the i-th second symbol set.

22. The transmitting end device according to any one of claims 15 to 21, characterized in that: Before sending the second modulated signal, the processing unit is further used for: The symbols in the second modulated signal are interleaved.

23. The transmitting end device according to claim 22, characterized in that: The second modulation signal includes N shape symbol groups, each of which includes K symbols, M×N=N shape × K, N shape is an integer greater than 1, K is an integer greater than 1, and the second modulated signal after the interleaving is expressed as: {the 0th symbol in the 0th symbol group, the 0th symbol in the 1st symbol group, ..., the Nth shape The 0th symbol in the -1st symbol group, the 1st symbol in the 0th symbol group, the 1st symbol in the 1st symbol group, ..., the Nth symbol shape -1 symbol in the 1st symbol group, ..., the K-1th symbol in the 0th symbol group, the K-1th symbol in the 1st symbol group, ..., the Nth shape -1 symbol group}.

24. The transmitting end device according to any one of claims 15 to 21, characterized in that: After acquiring the first modulated signal, before flipping the polarity of at least one symbol in at least one of the first symbol sets of the first modulated signal to obtain a second modulated signal including M×N symbols, the processing unit is further used to: interleaving each symbol of the first symbol set in the first modulated signal; After flipping the polarity of at least one symbol in at least one of the first symbol sets of the first modulated signal to obtain a second modulated signal including M×N symbols, and before sending the second modulated signal, the processing unit is further used to: The symbols in the second modulated signal are deinterleaved according to the interleaving method.

25. The transmitting end device according to claim 24, characterized in that: Each first symbol set in the first modulated signal includes R consecutive symbol subsets, each of the symbol subsets includes L symbols, N=R×L, R is an integer greater than 1, and L is an integer greater than 1. The first symbol set in the first modulated signal after the interleaving is expressed as: {the 0th symbol in the 0th symbol subset, the 0th symbol in the 1st symbol subset,…, the 0th symbol in the R-1th symbol subset, the 1st symbol in the 0th symbol subset, the 1st symbol in the 1st symbol subset,…, the 1st symbol in the R-1th symbol subset,…, the L-1th symbol in the 0th symbol subset, the L-1th symbol in the 1st symbol subset,…, the L-1th symbol in the R-1th symbol subset}.

26. A receiving device, characterized in that: include: a receiving unit and a processing unit; The receiving unit is used to: receive a first signal and identification information sent by a transmitting end and transmitted through a channel; The processing unit is used to: perform DC removal processing on the first signal to obtain a second signal, the second signal includes M symbol sets, each of the symbol sets includes N symbols, M is an integer greater than 1, N is an integer greater than 1, and the identification information is used to indicate the polarity reversal of the symbols in each of the symbol sets; The polarity of at least one symbol in at least one of the symbol sets is flipped according to the identification information to obtain a third signal including M×N symbols.

27. The receiving end device according to claim 26, characterized in that: The processing unit is specifically used for: Determine the jth symbol in the i-th second symbol set according to the identification information, where 0≤i≤M-1, 0≤j≤N-2; The polarities of all symbols after the jth symbol in the i-th second symbol set are reversed.

28. A communication system, characterized in that: include: A sending end device as described in any one of claims 15 to 25 and a receiving end device as described in any one of claims 26 to 27.

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