A method for generating an optical signal with bit reconfiguration

Abstract

The application provides a bit-reconstruction optical signal generation method, and relates to the field of optical fiber communication systems. The method comprises the following steps: processing a sending end signal by using a strengthened correlation coding circuit to obtain a signal with strong correlation; performing constellation mapping according to a partition mapping unit rule to obtain binary information bits after bit reconstruction; and modulating the signal by using optical modulation to obtain a bit-reconstruction optical signal. The optical system signal generated by using the method provided in the embodiment of the application can still achieve a low error code at a receiving end after transmission through an optical fiber channel, effectively improves system transmission reliability, and achieves the purpose of reducing system sending power.

Description

Technical Field

[0001] This invention relates to the field of optical communication, and in particular to a method for generating optical signals applicable to optical access and optical transmission systems in optical fiber communication systems. Background Technology

[0002] In recent years, with the rapid development of high-definition video, cloud computing, and 5G, the demand for high-speed data transmission has been increasing. This also means that communication systems face enormous challenges in capacity expansion. Optical fiber communication, with its advantages of high transmission bandwidth, large transmission capacity, and low loss performance, has long been a crucial infrastructure of the information society and a cornerstone of modern information society development, undertaking the tasks of information access, aggregation, and transmission. However, whether it is long-distance optical transmission or short-distance optical communication, the complexity and variability of the channel will affect the stability and reliability of information transmission, and users have placed more stringent requirements on communication quality. Furthermore, system cost and compatibility issues must also be considered. Therefore, how to utilize existing equipment to achieve fast and reliable transmission in optical fiber communication systems to meet user needs is one of the research hotspots in the field, which is beneficial for reducing signal transmission error rate and improving the reliability of optical fiber communication systems.

[0003] To address the aforementioned issues, source coding and channel coding techniques are widely used in optical fiber communication systems. By introducing controllable inter-symbol interference or adding redundancy through coding, reliable high-speed signal transmission is achieved. At the receiving end, the signal is received through the reverse process corresponding to the transmitting end. However, current coding techniques cannot perform calibration identification based on signal characteristics during transmission, and the correlation between the source information at the transmitting end and the information at the receiving end is weak. Therefore, to achieve better signal transmission performance, it is necessary to study the generation of optical signals at the transmitting end of optical fiber communication systems.

[0004] The present invention mainly designs a method for generating optical signals by bit reconstruction. The proposed method uses an enhanced correlation coding circuit and a partition mapping unit to complete bit reconstruction, achieving strong signal correlation at the transmitting end of the optical fiber communication system. Even after transmission through the optical fiber system, it still has high reliability at the receiving end, and can be successfully decoded with a low bit error rate. Summary of the Invention

[0005] The purpose of this invention is to provide a method for generating bit-reconstructed optical signals, which solves the problem of high decoding error rate at the receiver, while saving transmission power at the system transmitter and reducing costs.

[0006] To address the above problems, embodiments of the present invention provide a method for generating bit-reconstructed optical signals:

[0007] Acquire the initial binary information stream in the optical fiber communication system;

[0008] The initial binary information stream is transformed into a serial-to-parallel stream based on the system modulation order M, resulting in a binary information stream for the transmitting end that is transmitted in parallel with M lines.

[0009] The M parallel binary information streams from the transmitting end are grouped to obtain M / 2 groups of information streams;

[0010] Based on logic gates (NOT gates, XOR gates) and delayers, the correlation of the grouped information streams in the first M-2 rows is superimposed. The information in the same group needs to be attenuated by 6dB for the power of the even-numbered information bits in the delay attenuation unit.

[0011] The unattenuated signal is added to the attenuated signal by an adder, and the absolute value is taken to obtain a signal with absolute amplitude level. The amplitude sequence is the initial correlation signal.

[0012] The above calculations are performed separately on the signal packets from the transmitting end;

[0013] The initial correlation signal is bit-filled according to the system modulation order M, and the filled binary information with double bits is obtained.

[0014] Based on the concept of symmetry design, the last two bits of each symbol in the constellation design are kept specific and used as the basis for distinguishing the four quadrants to obtain the partition bits; at the same time, the symmetrical positions of each quadrant have the same remaining bits (except for the partition bits).

[0015] According to the preset constellation diagram, constellation mapping is performed, and high-power and low-power regions are divided at the same time. Most of the signal is mapped to the low-power region near the origin.

[0016] By using an optical modulator to load the bit-reconstructed information stream onto a carrier optical wave, a bit-reconstructed optical signal suitable for optical fiber communication systems can be obtained.

[0017] Beneficial effects of the embodiments of the present invention:

[0018] The method provided in this invention generates a bit-reconstructed optical signal. A portion of the response signal is applied to multiple modulation signals to generate multi-level modulation signals, which are then mapped to a constellation according to preset instructions. The bit reconstruction part achieves strong correlation between the transmitting end (TX) and receiving end (RX) information, reducing the bit error rate and improving the reliability of the optical fiber communication system. Simultaneously, in the partition mapping unit, constellation points in low-power regions are selected for mapping as much as possible, reducing the system's transmission power and further saving costs. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the invention, form part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute a limitation thereof.

[0020] In the attached diagram:

[0021] Figure 1 This is a block diagram of a bit-reconstructed optical signal generation method according to the present invention.

[0022] Figure 2 This is a schematic diagram of the partition mapping unit principle in this invention. Detailed Implementation

[0023] Referring to the accompanying drawings, the foregoing and other features of the embodiments of the present invention will become apparent from the following description. These embodiments are merely exemplary and not intended to limit the invention. To enable those skilled in the art to readily understand the principles and implementation methods of the present invention, the working principle of the embodiments of the present invention is illustrated using a bit reconstruction 64QAM optical signal generation method suitable for OFDM optical access systems as an example.

[0024] Example 1:

[0025] In a 64QAM-OFDM optical access system, the system transmitter adopts, for example... Figure 1 The optical signal generation method shown here, where M=6, includes the following steps S101-S104:

[0026] S101: Perform serial-to-parallel conversion on the binary information stream from the transmitting end and group it into pairs. In this embodiment, 64QAM signal is selected. Therefore, the source information needs to be divided into six paths, with each pair forming a group. The first two groups of signals are reconstructed into bits, and the last group of signals is directly input into the partition mapping unit to wait for constellation mapping to be completed together with the enhanced correlation coding signal.

[0027] S102: The first two sets of information after serial-to-parallel conversion are input into the pre-encoding circuit to generate related signals with sequential correlation, and the signal power of data2 and data4 is attenuated by 6dB in the delay attenuation unit; the unattenuated signal is added to the attenuated signal through an adder and the absolute value is taken.

[0028] S103: In the partition mapping unit, the absolute level amplitude signal {0, 1, 2, 3} obtained after the enhanced correlation coding circuit is first bit-filled according to the rule 0-01; 1-11; 2-10; 3-11. Simultaneously, symmetry is considered when designing the constellation diagram; the last two bits of the 64QAM symbol are kept as specific bits, serving as the basis for distinguishing the four quadrants. Symmetrical positions in each quadrant have the same four bits, such as... Figure 2As shown, 11, 01, 10, and 11 represent the four quadrants respectively, and the constellation point positions are designed and the high-power area and low-power area are divided using the first quadrant as an example.

[0029] S104: The correlated signals after partitioning are mapped onto multiple subcarriers, and the frequency domain signals on the parallel subcarriers are converted to the time domain using an inverse Fast Fourier Transform. A cyclic prefix is ​​inserted before each OFDM symbol. Finally, the time domain signals of the multiple subcarriers are superimposed through parallel-to-serial conversion to form a bit-reconstructed 64QAM optical signal suitable for OFDM optical access systems in the optical line terminal.

Claims

1. A method for generating a bit-reconstructed optical signal, characterized in that, include: Acquire the initial binary information stream in the optical fiber communication system; The initial binary information stream is subjected to enhanced correlation coding, specifically including: performing serial-to-parallel conversion on the initial binary information stream to obtain M parallel transmitting binary information streams; grouping the M information streams into pairs to obtain M / 2 groups of information streams; performing correlation superposition on the first M-2 groups of streams based on NOT gates, XOR gates, and delay units, and attenuating the signal power of the second path of each group by 6dB in the delay attenuation unit; adding the unattenuated signal and the attenuated signal using an adder and taking their absolute values ​​to obtain a signal with absolute amplitude level, the amplitude sequence of which is the initial correlation signal; The initial correlation signal is partitioned and mapped according to the modulation order M. Specifically, the initial correlation signal is bit-filled to obtain binary information with double bits. A symmetrical constellation diagram is designed, and the last two bits of each symbol are kept as specific partition bits to divide the quadrants. The symmetrical positions of each quadrant have the same remaining bits, where the remaining bits do not include the partition bits. Constellation mapping is performed according to the preset constellation diagram, and high-power and low-power regions are divided at the same time. Most of the signal is mapped to the low-power region near the origin. The reconstructed binary information stream is modulated onto an optical carrier to obtain a bit-reconstructed optical signal.

2. The method for generating a bit-reconstructed optical signal according to claim 1, characterized in that, The initial binary information stream is subjected to enhanced correlation coding to obtain an initial correlation signal, specifically including: Perform serial-to-parallel conversion based on the system modulation order M, where M is an integer greater than 2, to obtain a binary information stream with M parallel lines at the transmitting end; The M parallel binary information streams from the transmitting end are grouped to obtain M / 2 groups of information streams; Based on NOT gates, XOR gates, and delay units, the correlation of the first M-2 rows of grouped information streams is superimposed. The information of the first (M-2) / 2 groups needs to be attenuated by 6dB for the signal power of the second path of each group in the delay attenuation unit. The unattenuated signal is added to the attenuated signal by an adder, and the absolute value is taken to obtain a signal with absolute amplitude level, whose amplitude sequence is {0, 1, 2, 3}, which is the initial correlation signal.

3. The method for generating a bit-reconstructed optical signal according to claim 1, characterized in that, The initial correlation signal is partitioned and mapped according to the modulation order to obtain the reconstructed binary information stream, which specifically includes: The initial correlation signal is bit-filled based on the system modulation order M, resulting in binary information with double bits. Based on the concept of symmetry design, the last two bits of each symbol are kept specific in the constellation design and used as the basis for distinguishing the four quadrants to obtain the partition bits; at the same time, the symmetrical position of each quadrant has the same remaining bits, wherein the remaining bits do not include the partition bits. The system divides the signal into high-power and low-power regions and performs constellation mapping according to a preset constellation diagram. Most of the signal is mapped to the low-power region, which is closer to the origin.

4. The method for generating a bit-reconstructed optical signal according to claim 1, characterized in that... Modulating the reconstructed binary information stream onto an optical carrier to obtain a reconstructed optical signal specifically includes: By using an optical modulator to load the bit-reconstructed information stream onto a carrier optical wave, a bit-reconstructed optical signal suitable for optical fiber communication systems can be obtained.

5. The method for generating a bit-reconstructed optical signal according to claim 2, characterized in that, Specifically, it includes: The signal from the transmitting end is converted from serial to parallel, and the original data becomes data1, data2, data3... and then grouped in pairs so that every two adjacent data sets form a group. Each group of data is then input into the subsequent circuit. Note that the last group of data is directly input into the partition mapping unit.

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