EP-4742583-A1 - DATA PROCESSING METHOD AND DATA PROCESSING APPARATUS

EP4742583A1EP 4742583 A1EP4742583 A1EP 4742583A1EP-4742583-A1

Abstract

Embodiments of this application disclose a data processing method and a data processing apparatus. The data processing method is applied to a receiver in the field of optical transmission, and is mainly used to implement frame synchronization. In this application, a differential processing operation is introduced during frame synchronization performed by the receiver. Specifically, the receiver performs differential processing on received data after channel transmission, to obtain differential data; and performs differential processing on an obtained pilot sequence, to obtain a differential pilot sequence. Further, the receiver performs cross-correlation calculation on the differential data and the differential pilot sequence, and determines a frame start location in the received data based on a result of the cross-correlation calculation, to complete frame synchronization. In this manner, impact of a laser frequency offset on the frame synchronization performed by the receiver is reduced, and effects of the frame synchronization are improved.

Inventors

Li, Zibin
HUANG, Kechao
MA, Huixiao

Assignees

Huawei Technologies Co., Ltd.

Dates

Publication Date: 20260513
Application Date: 20240527

Claims (20)

A data processing method, comprising: receiving a symbol set derived from a plurality of data frames after channel transmission, wherein the plurality of data frames are sent by a transmitter, in a polarization direction, each of the data frames comprises N symbols, every M consecutive symbols of the N symbols comprise one pilot symbol at a fixed location and M-1 payload symbols, N=M×Q, Q is an even number, M is an integer greater than or equal to 1, the symbol set comprises R symbol subsets, each of the symbol subsets comprises W symbols, R is an integer greater than 1, and W is an integer greater than or equal to 1; performing differential processing on each of the symbol subsets to obtain a corresponding differential symbol subset, so as to obtain a total of R differential symbol subsets; obtaining a pilot sequence, and performing differential processing on the pilot sequence to obtain a differential pilot sequence, wherein the pilot sequence comprises Z pilot symbols, 2≤Z≤Q, the Z pilot symbols in the pilot sequence are in one-to-one correspondence with Z pilot symbols in the data frame, any pilot symbol in the pilot sequence is c times a corresponding pilot symbol in the data frame, and c is not equal to 0; and determining a frame start location in the symbol set based on the R differential symbol subsets and the differential pilot sequence.
The method according to claim 1, wherein the Z pilot symbols in the pilot sequence are in one-to-one correspondence with Z consecutive pilot symbols in the data frame.
The method according to claim 2, wherein performing the differential processing on the symbol subset to obtain the differential symbol subset comprises: obtaining K symbols adjacent to a start location or an end location of the symbol subset, wherein K=a×M, and 1≤a≤Z; and performing differential processing on a symbol sequence that comprises the symbol subset and the K symbols, to obtain the differential symbol subset.
The method according to claim 3, wherein performing the differential processing on the symbol sequence that comprises the symbol subset and the K symbols, to obtain the differential symbol subset comprises: performing conjugate calculation on a v th symbol in the symbol sequence; and multiplying a result of the conjugate calculation by a (v+K) th symbol in the symbol sequence to obtain a v th symbol in the differential symbol subset, wherein 0≤v≤W-1.
The method according to claim 3, wherein performing the differential processing on the symbol sequence that comprises the symbol subset and the K symbols, to obtain the differential symbol subset comprises: performing conjugate calculation on a (v+K) th symbol in the symbol sequence; and multiplying a result of the conjugate calculation by a v th symbol in the symbol sequence to obtain a v th symbol in the differential symbol subset, wherein 0≤v≤W-1.
The method according to any one of claims 2 to 5, wherein performing the differential processing on the pilot sequence to obtain the differential pilot sequence comprises: performing right cyclic shift on the pilot sequence by a symbols, wherein 1≤a≤Z; performing conjugate calculation on a pilot sequence obtained through the right cyclic shift by the a symbols, to obtain a conjugate sequence; and multiplying, in one-to-one correspondence, Z symbols in the conjugate sequence by the Z pilot symbols in the pilot sequence to obtain the differential pilot sequence.
The method according to any one of claims 2 to 5, wherein performing the differential processing on the pilot sequence to obtain the differential pilot sequence comprises: performing left cyclic shift on the pilot sequence by a symbols, wherein 1≤a≤Z; performing conjugate calculation on a pilot sequence obtained through the left cyclic shift by the a symbols, to obtain a conjugate sequence; and multiplying, in one-to-one correspondence, Z symbols in the conjugate sequence by the Z pilot symbols in the pilot sequence to obtain the differential pilot sequence.
The method according to any one of claims 3 to 7, wherein 1 ≤ a ≤ Z / 2 , and b represents rounding down a positive real number b.
The method according to any one of claims 1 to 8, wherein the pilot sequence comprises Q pilot symbols, and the Q pilot symbols in the pilot sequence are the same as Q pilot symbols in the data frame.
The method according to any one of claims 1 to 9, wherein determining the frame start location in the symbol set based on the R differential symbol subsets and the differential pilot sequence comprises: performing cross-correlation calculation on the R differential symbol subsets and the differential pilot sequence; and determining the frame start location in the symbol set based on a result of the cross-correlation calculation.
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 10.
A data processing apparatus, comprising: a receiving unit, a first differential processing unit, a second differential processing unit, and an identification unit, wherein the receiving unit is configured to receive a symbol set derived from a plurality of data frames after channel transmission, wherein the plurality of data frames are sent by a transmitter, wherein in a polarization direction, the data frame comprises N symbols, every M consecutive symbols of the N symbols comprise one pilot symbol at a fixed location and M-1 payload symbols, N=M×Q, Q is an even number, M is an integer greater than or equal to 1, the symbol set comprises R symbol subsets, each of the symbol subsets comprises W symbols, R is an integer greater than 1, and W is an integer greater than or equal to 1; the first differential processing unit is configured to perform differential processing on each of the symbol subsets to obtain a corresponding differential symbol subset, so as to obtain a total of R differential symbol subsets; the second differential processing unit is configured to: obtain a pilot sequence, and perform differential processing on the pilot sequence to obtain a differential pilot sequence, wherein the pilot sequence comprises Z pilot symbols, 1≤Z≤Q, the Z pilot symbols in the pilot sequence are in one-to-one correspondence with Z pilot symbols in the data frame, any pilot symbol in the pilot sequence is c times a corresponding pilot symbol in the data frame, and c is not equal to 0; and the identification unit is configured to determine a frame start location in the symbol set based on the R differential symbol subsets and the differential pilot sequence.
The data processing apparatus according to claim 12, wherein the Z pilot symbols in the pilot sequence are in one-to-one correspondence with Z consecutive pilot symbols in the data frame.
The data processing apparatus according to claim 13, wherein the first differential processing unit is specifically configured to: obtain K symbols adjacent to a start location or an end location of the symbol subset, wherein K=a×M, and 1≤a≤Z; and perform differential processing on a symbol sequence that comprises the symbol subset and the K symbols, to obtain the differential symbol subset.
The data processing apparatus according to claim 14, wherein the first differential processing unit is specifically configured to: perform conjugate calculation on a v th symbol in the symbol sequence; and multiply a result of the conjugate calculation by a (v+K) th symbol in the symbol sequence to obtain a v th symbol in the differential symbol subset, wherein 0≤v≤W-1.
The data processing apparatus according to claim 14, wherein the first differential processing unit is specifically configured to: perform conjugate calculation on a (v+K) th symbol in the symbol sequence; and multiply a result of the conjugate calculation by a v th symbol in the symbol sequence to obtain a v th symbol in the differential symbol subset, wherein 0≤v≤W-1.
The data processing apparatus according to any one of claims 13 to 16, wherein the second differential processing unit is specifically configured to: perform right cyclic shift on the pilot sequence by a symbols, wherein 1≤a≤Z; perform conjugate calculation on a pilot sequence obtained through the right cyclic shift by the a symbols, to obtain a conjugate sequence; and multiply, in one-to-one correspondence, Z symbols in the conjugate sequence by the Z pilot symbols in the pilot sequence to obtain the differential pilot sequence.
The data processing apparatus according to any one of claims 13 to 16, wherein the second differential processing unit is specifically configured to: perform left cyclic shift on the pilot sequence by a symbols, wherein 1≤a≤Z; perform conjugate calculation on a pilot sequence obtained through the left cyclic shift by the a symbols, to obtain a conjugate sequence; and multiply, in one-to-one correspondence, Z symbols in the conjugate sequence by the Z pilot symbols in the pilot sequence to obtain the differential pilot sequence.
The data processing apparatus according to any one of claims 14 to 18, wherein 1 ≤ a ≤ Z / 2 , and b represents rounding down a positive real number b.
The data processing apparatus according to any one of claims 12 to 19, wherein the pilot sequence comprises Q pilot symbols, and the Q pilot symbols in the pilot sequence are the same as Q pilot symbols in the data frame.

Description

This application claims priority to Chinese Patent Application No. 202311130829.9, filed with the China National Intellectual Property Administration on August 31, 2023 and entitled "DATA PROCESSING METHOD AND DATA PROCESSING 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 data processing method and a data processing apparatus. BACKGROUND Driven by advancements in 5G, cloud computing, big data, artificial intelligence, and the like, high-speed optical transport networks are evolving toward larger capacity, packet-based, and intelligent directions. Coherent optical communication systems use amplitudes, phases, polarization, and frequencies of optical waves to carry information. To resist optical signal distortion caused by dispersion, polarization-dependent impairment, noise, non-linear effects, and other factors in a transmission process and maintain long-distance transmission, the coherent optical communication systems typically introduce some designed fixed symbol sequences to transmission symbol sequences, to help a receiver restore transmitted symbols. Frame formats adopted in 400ZR and 800ZR scenarios incorporate consecutive training sequences whose correlation exhibits high tolerance to laser frequency offset. However, 800LR scenarios adopt an extremely simplified frame structure, including a pilot sequence formed by periodically inserted pilot symbols. Such a pilot sequence has a long symbol period, and correlation of the pilot sequence is highly sensitive to laser frequency offset. Phase noise introduced by the laser frequency offset greatly reduces the correlation of the pilot sequence, and consequently severely affects frame synchronization performed by the receiver. SUMMARY Embodiments of this application provide a data processing method and a data processing apparatus, to reduce impact of a laser frequency offset on frame synchronization performed by a receiver, and improve an effect of the frame synchronization. According to a first aspect, an embodiment of this application provides a data processing method, and the data processing method is applied to a receiver. A plurality of consecutive data frames sent by a transmitter are transmitted to the receiver over a channel. It should be understood that received data after channel transmission may be considered as a symbol set including a plurality of symbols. Further, the symbol set includes R symbol subsets, and each of the symbol subsets includes W symbols. R is an integer greater than 1, and W is an integer greater than or equal to 1. Specifically, the receiver performs differential processing on each of the symbol subsets to obtain a corresponding differential symbol subset, so as to obtain a total of R differential symbol subsets. The receiver obtains a pilot sequence, and performs differential processing on the pilot sequence to obtain a differential pilot sequence, where the pilot sequence includes Z pilot symbols, 2≤Z≤Q, the Z pilot symbols in the pilot sequence are in one-to-one correspondence with Z pilot symbols in the data frame, any pilot symbol in the pilot sequence is c times a corresponding pilot symbol in the data frame, and c is not equal to 0. Further, the receiver determines a frame start location in the symbol set based on the R differential symbol subsets and the differential pilot sequence. It should be noted that each of the data frames sent by the transmitter satisfies the following characteristics: In a polarization direction, the data frame includes N symbols, every M consecutive symbols of the N symbols include one pilot symbol at a fixed location and M-1 payload symbols, N=M×Q, Q is an even number, M is an integer greater than or equal to 1, Q pilot symbols are generated by using a target polynomial and a seed, each pilot symbol is one of -A-Aj, -A+Aj, A-Aj, and A+Aj, and A is a real number. In this implementation, considering that a frequency difference between a laser at the transmitter and a laser at the receiver, that is, a laser frequency offset, affects frame synchronization performed by the receiver, in this application, a differential processing operation is introduced in a process of performing the frame synchronization by the receiver, to reduce the impact of the laser frequency offset on the frame synchronization performed by the receiver, and improve the effect of the frame synchronization. In addition, the pilot symbols generated by the transmitter in the foregoing manner have good autocorrelation characteristics and cross-correlation characteristics, and satisfy a direct current balance. This helps the receiver restore signal quality. In some possible implementations, the Z pilot symbols in the pilot sequence are in one-to-one correspondence with Z consecutive pilot symbols in the data frame, so that differential processing complexity is lower. In some possible imple