EP-4742562-A1 - SIGNAL PROCESSING METHOD AND RELATED APPARATUS

EP4742562A1EP 4742562 A1EP4742562 A1EP 4742562A1EP-4742562-A1

Abstract

Embodiments of this application disclose a signal processing method and a related apparatus. The signal processing method may be applied to an optical communication scenario. The method in embodiments of this application includes: A transmitter inverts polarities of some symbols in a first modulated signal to obtain a second modulated signal, so that an absolute value of a sum of values of all symbols in the second modulated signal is less than an absolute value of a sum of values of all symbols in the first modulated signal. In this way, power of a low-frequency part in the second modulated signal is suppressed. This helps a receiver perform direct current removal on the signal to resist impact of low-frequency noise on a channel on transmission performance. In addition, the receiver performs inverse transformation of power spectrum adjustment on the received signal based on identification information, to restore the original signal that is before the transmitter performs power spectrum adjustment.

Inventors

WANG, DAWEI
MA, Huixiao
LU, Yao
LIAN, Kunjian

Assignees

Huawei Technologies Co., Ltd.

Dates

Publication Date: 20260513
Application Date: 20240704

Claims (20)

A signal processing method, comprising: obtaining a first modulated signal, wherein the first modulated signal comprises M first symbol sets, each first symbol set comprises N symbols, M is an integer greater than 1, and N is an integer greater than 1; inverting a polarity of at least one symbol in at least one first symbol set in the first modulated signal to obtain a second modulated signal comprising M×N symbols, wherein an absolute value of a sum of values of all the symbols in the second modulated signal is less than an absolute value of a sum of values of all symbols in the first modulated signal; and sending the second modulated signal.
The method according to claim 1, wherein the inverting the polarity of the at least one symbol in the at least one first symbol set in the first modulated signal comprises: determining a value j min of j corresponding to a minimum sum of values of all symbols in an i th second symbol set, wherein the i th second symbol set is obtained by inverting polarities of all symbols after a j th symbol in the i th first symbol set, 0≤i≤M-1, and 0≤j≤N-2; and inverting polarities of all symbols after a j mín th symbol in the i th first symbol set.
The method according to claim 2, wherein the method further comprises: generating identification information, wherein the identification information indicates a position of the j min th symbol in the i th first symbol set.
The method according to claim 1, wherein the sum of the values of all the symbols in the second modulated signal is equal to 0.
The method according to claim 4, wherein the inverting the polarity of the at least one symbol in the at least one first symbol set in the first modulated signal comprises: obtaining a sum of values of all symbols in an i th first symbol set, wherein 0≤i≤M-1; and if the sum of the values of all the symbols in the i th first symbol set is equal to 0, keeping polarities of all the symbols in the i th first symbol set unchanged; or if the sum of the values of all the symbols in the i th first symbol set is not equal to 0, inverting a polarity of at least one symbol in the i th first symbol set to obtain an i th second symbol set, wherein a sum of values of all symbols in the i th second symbol set is equal to 0.
The method according to claim 5, wherein the inverting the polarity of the at least one symbol in the i th first symbol set to obtain the i th second symbol set comprises: inverting polarities of all symbols after a j th symbol in the i th first symbol set to obtain the i th second symbol set, wherein 0≤j≤N-2.
The method according to claim 6, wherein the method further comprises: generating identification information, wherein the identification information indicates a position of a j th symbol in the i th second symbol set.
The method according to any one of claims 1 to 7, wherein before the sending the second modulated signal, the method further comprises: interleaving the symbols in the second modulated signal.
The method according to claim 8, wherein the second modulated signal comprises N shape symbol groups, each symbol group comprises K symbols, M × N=N shape × K, N shape is an integer greater than 1, K is an integer greater than 1, and an interleaved second modulated signal is represented as: {a 0 th symbol in a 0 th symbol group, a 0 th symbol in a 1 st symbol group, ..., a 0 th symbol in an (N shape - 1) th symbol group, a 1 st symbol in the 0 th symbol group, a 1 st symbol in the 1 st symbol group, ..., a 1 st symbol in the (N shape - 1) th symbol group, ..., a (K-1) th symbol in the 0 th symbol group, a (K-1) th symbol in the 1 st symbol group, ..., a (K-1) th symbol in the (N shape - 1) th symbol group}.
The method according to any one of claims 1 to 7, wherein after the obtaining the first modulated signal, and before the inverting the polarity of the at least one symbol in the at least one first symbol set in the first modulated signal to obtain the second modulated signal comprising the M×N symbols, the method further comprises: interleaving the symbols in each first symbol set in the first modulated signal; and after the inverting the polarity of the at least one symbol in the at least one first symbol set in the first modulated signal to obtain the second modulated signal comprising the M×N symbols, and before the sending the second modulated signal, the method further comprises: de-interleaving the symbols in the second modulated signal based on how they are interleaved.
The method according to claim 10, wherein each first symbol set in the first modulated signal comprises R consecutive symbol subsets, each symbol subset comprises L symbols, N=R × L, R is an integer greater than 1, L is an integer greater than 1, and a first symbol set in an interleaved first modulated signal is represented as: {a 0 th symbol in a 0 th symbol subset, a 0 th symbol in a 1 st symbol subset, ..., a 0 th symbol in an (R - 1) th symbol subset, a 1 st symbol in the 0 th symbol subset, a 1 st symbol in the 1 st symbol subset, ..., a 1 st symbol in the (R - 1) th symbol subset, ..., an (L-1) th symbol in the 0 th symbol subset, an (L-1) th symbol in the 1 st symbol subset, ..., an (L-1) th symbol in the (R - 1) th symbol subset}.
A signal processing method, comprising: receiving a first signal and identification information that are sent by a transmitter through a channel; performing direct current removal on the first signal to obtain a second signal, wherein the second signal comprises M symbol sets, each symbol set comprises N symbols, M is an integer greater than 1, N is an integer greater than 1, and the identification information indicates polarity inversion statuses of the symbols in each symbol set; and inverting a polarity of at least one symbol in at least one symbol set based on the identification information to obtain a third signal comprising M×N symbols.
The method according to claim 12, wherein the inverting the polarity of the at least one symbol in the at least one second symbol set based on the identification information comprises: determining a j th symbol in an i th second symbol set based on the identification information, wherein 0≤i≤M-1, and 0≤j≤N-2; and inverting polarities of all symbols after the j th symbol in the i th second symbol set.
A chip, wherein the chip comprises a processor and a memory, the memory and the processor are connected to each other through a line, the memory stores instructions, and the processor is configured to perform the method according to any one of claims 1 to 13.
A transmitter device, comprising a processing unit and a sending unit, wherein the processing unit is configured to: obtain a first modulated signal, wherein the first modulated signal comprises M first symbol sets, each first symbol set comprises N symbols, M is an integer greater than 1, and N is an integer greater than 1; and invert a polarity of at least one symbol in at least one first symbol set in the first modulated signal to obtain a second modulated signal comprising M×N symbols, wherein an absolute value of a sum of values of all the symbols in the second modulated signal is less than an absolute value of a sum of values of all symbols in the first modulated signal; and the sending unit is configured to send the second modulated signal.
The transmitter device according to claim 15, wherein the processing unit is specifically configured to: determine a value j min of j corresponding to a minimum sum of values of all symbols in an i th second symbol set, wherein the i th second symbol set is obtained by inverting polarities of all symbols after a j th symbol in the i th first symbol set, 0≤i≤M-1, and 0≤j≤N-2; and invert polarities of all symbols after a j mín th symbol in the i th first symbol set.
The transmitter device according to claim 16, wherein the processing unit is further configured to: generate identification information, wherein the identification information indicates a position of the j min th symbol in the i th first symbol set.
The transmitter device according to claim 15, wherein the sum of the values of all the symbols in the second modulated signal is equal to 0.
The transmitter device according to claim 18, wherein the processing unit is specifically configured to: obtain a sum of values of all symbols in an i th first symbol set, wherein 0≤i≤M-1; and if the sum of the values of all the symbols in the i th first symbol set is equal to 0, keep polarities of all the symbols in the i th first symbol set unchanged; or if the sum of the values of all the symbols in the i th first symbol set is not equal to 0, invert a polarity of at least one symbol in the i th first symbol set to obtain an i th second symbol set, wherein a sum of values of all symbols in the i th second symbol set is equal to 0.
The transmitter device according to claim 19, wherein the processing unit is specifically configured to: invert polarities of all symbols after a j th symbol in the i th first symbol set to obtain the i th second symbol set, wherein 0≤j≤N-2.

Description

This application claims priority to Chinese Patent Application No. 202311034394.8, filed with the China National Intellectual Property Administration on August 15, 2023 and entitled "SIGNAL PROCESSING METHOD AND RELATED APPARATUS", which is incorporated herein by reference in its entirety. TECHNICAL FIELD Embodiments of this application relate to the field of optical communication, and in particular, to a signal processing method and a related apparatus. BACKGROUND In actual deployment of an optical communication system, an impairment effect from a channel causes signal quality degradation, and a bit error rate of signals significantly increases. In this case, transmission performance of the optical communication system is limited. For an application scenario of short-distance optical interconnection, a solution combining intensity-modulation direct-detection (Intensity-Modulation Direct-Detection, IMDD) and a higher-order modulation format is mainly used, but a higher-order modulated signal is extremely vulnerable to impact of low-frequency noise such as a baseline drift. In addition, signal distortion caused by chromatic dispersion (Chromatic dispersion, CD) brings extra transmission penalties. In this case, transmission bandwidth of the system is limited. In conventional technologies, to reduce impact of the low-frequency noise and the chromatic dispersion on optical transmission, an equalization algorithm is usually used at a receiver for channel compensation. However, if processing is performed only at the receiver, problems such as high algorithm complexity and an insufficient compensation capability in a harsh environment exist. SUMMARY Embodiments of this application provide a signal processing method and a related apparatus. A transmitter inverts polarities of some symbols in a modulated signal, to suppress power of a low-frequency part. This helps resist impact of low-frequency noise on a channel on transmission performance. According to a first aspect, an embodiment of this application provides a signal processing method. The method is applied to a transmitter. Specifically, the transmitter obtains a first modulated signal, where the first modulated signal includes M first symbol sets, each first symbol set includes N symbols, and both M and N are integers greater than 1. For example, N is usually an integer multiple of 2. It should be understood that each first symbol set may also be referred to as a symbol block (block), and each symbol in the block may include a plurality of bits. Then, the transmitter inverts a polarity of at least one symbol in at least one first symbol set in the first modulated signal to obtain a second modulated signal including M×N symbols. An absolute value of a sum of values of all the symbols in the second modulated signal is less than an absolute value of a sum of values of all symbols in the first modulated signal. Further, the transmitter sends the second modulated signal. Further, the sum of the values of all the symbols in the second modulated signal is less than or equal to a maximum value of a single symbol in the second modulated signal. In this implementation, the transmitter inverts polarities of some symbols in the first modulated signal to obtain the second modulated signal, so that the absolute value of the sum of the values of all the symbols in the second modulated signal is less than the absolute value of the sum of the values of all the symbols in the first modulated signal. In this way, power of a low-frequency part in the second modulated signal is suppressed. This helps a receiver perform direct current removal on the signal to resist impact of low-frequency noise on a channel on transmission performance. Compared with a manner of performing channel compensation at the receiver, the processing manner at the transmitter has lower complexity. In some possible implementations, inverting the polarity of the at least one symbol in the at least one first symbol set in the first modulated signal includes: determining a value jmin of j corresponding to a minimum sum of values of all symbols in an ith second symbol set, where the ith second symbol set is obtained by inverting polarities of all symbols after a jth symbol in an ith first symbol set, 0≤i≤M-1, and 0≤j≤N-2; and inverting polarities of all symbols after a jmínth symbol in the ith first symbol set. In this implementation, for the ith first symbol set, there are N-1 different polarity inversion manners in total to obtain ith second symbol sets, and a polarity inversion manner in which the minimum sum of the values of all the symbols in the ith second symbol set is obtained is selected from the N-1 different polarity inversion manners, so that an effect of suppressing power of the second modulated signal at a low frequency can be improved. In some possible implementations, the method further includes: generating identification information, where the identification information indicates a position of