A parallel optical signal modulation and demodulation method and system based on micro LED array optical interconnection

Abstract

This invention relates to the field of optical signal demodulation, specifically to a parallel optical signal modulation and demodulation method and system based on MicroLED array optical interconnects, comprising: a data acquisition module for acquiring raw data from the external environment or equipment and converting it into a form suitable for subsequent processing; a data processing module for receiving information from the data acquisition module and preprocessing it; and a data analysis module. The overall architecture of high-speed DSP+MicroLED channels breaks away from the traditional approach of "hundreds of channels, DSP-free, wide but slow." By introducing SerDes and DSP modulation and demodulation, the single-channel rate is increased by an order of magnitude, achieving a total bandwidth of ≥120Gbps with ≤32 channels. Simultaneously, single-channel 10–20Gbps OOK / PAM4 modulation is achieved: clearly defining high-order modulation of MicroLED under GHz-level bandwidth conditions, overcoming the carrier lifetime limitations of MicroLED, and ensuring low bit error rate through pre-emphasis, equalization, and FEC.

Description

Technical Field

[0001] This invention belongs to the field of optical signal demodulation technology, specifically a parallel optical signal modulation and demodulation method and system based on MicroLED array optical interconnect. Background Technology

[0002] With the ever-increasing bandwidth demands of data centers and high-performance computing systems, optical interconnects have become a research hotspot as an alternative due to their advantages such as high bandwidth, low latency, and low power consumption. MicroLED array optical interconnects are an emerging optical interconnect method that transmits low-speed signals in parallel through hundreds of MicroLED channels, avoiding the use of complex DSP modulation and demodulation algorithms, thereby achieving low-power, wide-bandwidth, and slow data transmission.

[0003] A patent with publication number CN 113132009 B discloses a coherent optical module and an optical communication system. The optical module includes: a transmitting end, in which a first beam splitter splits the output of a laser into one local oscillator beam and N optical carrier beams of equal power. The local oscillator beam is coarsely tuned and then emitted through a first circulator; each coherent optical transmitter receives a set of four modulated electrical signals and modulates them with one optical carrier beam into polarization-multiplexed signal light, which is then emitted through a second circulator; a receiving end, in which the local oscillator beam received by the first circulator is amplified by an amplifier and then split into N local oscillator beams by a second beam splitter, which are then finely tuned by finely adjustable delay lines; each polarization-independent coherent optical receiver receives the signal light of the optical link from the second circulator one-to-one, and then performs coherent mixing and photoelectric conversion with the finely tuned local oscillator beam to obtain a set of four electrical signals, which are output to an N-channel coherent optical modulation and demodulation DSP chip for demodulation.

[0004] Currently, traditional electrical interconnection methods are gradually revealing their limitations, including bandwidth bottlenecks, high power consumption, poor signal integrity, low bandwidth utilization (each channel only transmits low-speed signals, failing to fully utilize the modulation potential of MicroLEDs), and poor broadband scalability (as bandwidth demand increases, the number of channels needs to increase linearly, leading to a sharp increase in hardware costs and layout difficulty).

[0005] Therefore, the present invention provides a parallel optical signal modulation and demodulation method and system based on MicroLED array optical interconnect. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0007] Firstly, the technical solution adopted by the present invention to solve its technical problem is: a parallel optical signal modulation and demodulation system based on MicroLED array optical interconnection, comprising: The data acquisition module is used to acquire raw data from the external environment or equipment and convert it into a form suitable for subsequent processing. The data processing module is used to receive information from the data acquisition module and preprocess it. The data analysis module uses advanced algorithms to perform in-depth analysis of the received data and extract valuable information or patterns. The control decision module is used to formulate corresponding strategies or instructions based on the received data analysis reports and to provide feedback to users through the user interface. The user interface is used for two-way communication with the control decision module.

[0008] Preferably, the data processing module is used to perform noise removal processing on the data collected by the data acquisition module, and the processed data will be sent to the data analysis module for data analysis processing.

[0009] Preferably, the data results analyzed by the data analysis module are transmitted to the control decision module for control decision processing.

[0010] Preferably, the user interface is equipped with a data transmission unit and a data receiving unit. The data transmission unit converts the collected parallel data into a high-speed serial data stream through SerDes; then encodes and modulates the serial data through DSP; and drives a designated channel in the MicroLED array to emit light.

[0011] Preferably, the data receiving unit uses a photodetector to array the light-emitting channels inside the MicroLED and receives the light signals inside the MicroLED; subsequently, the received light signals are sampled, decided, and decoded by a DSP; and finally, the serial data is restored to the original parallel data by a SerDes.

[0012] Secondly, a parallel optical signal modulation and demodulation method based on MicroLED array optical interconnects includes the following steps: S1. It adopts a deep convolutional neural network as the core model architecture, which mainly consists of an input layer, multiple hidden layers, convolutional layers, pooling layers, and an output layer. It mainly achieves high-precision signal processing through hierarchical data extraction. Light crosstalk is reduced by placing tiny optical barriers between adjacent MicroLEDs. These optical barriers are contrasting materials with high refractive index, such as silicon dioxide or silicon nitride, which can effectively prevent light from propagating from one MicroLED to another. The OOK on / off keying modulation technology is introduced. OOK is a simple modulation method in which the "on" state represents sending 1 and the "off" state represents sending 0. This modulation method is not only simple and easy to implement, but also has low hardware requirements, making it suitable for low-power application scenarios. In addition, in order to ensure signal quality, an adaptive threshold detection mechanism is used to distinguish the "on" and "off" states in the OOK signal, thereby improving the robustness and anti-interference ability of the system. Considering that performance fluctuations may occur in MicroLED array optical interconnect systems due to temperature changes, an integrated temperature sensor is used to monitor the ambient temperature in real time and automatically adjust the driving current according to temperature changes to maintain the stable operation of the MicroLED. This method not only improves the stability of the system but also extends the lifespan of the MicroLED. S2. Use LDPC low-density parity-check code or FEC forward error correction code to improve data transmission reliability; S3. At the receiving end, DFE decision feedback equalization or MLSE maximum likelihood sequence estimation algorithm is used to compensate for channel distortion. These algorithms can effectively reduce signal distortion caused by channel characteristics, thereby improving the performance of the communication system. The MLSE algorithm considers all possible transmission sequences and selects the one with the highest probability as the actual transmission sequence. Assuming there are L possible transmission symbols, at each time t, MLSE needs to calculate the probability of all \(2^L) different paths and then select the path with the highest cumulative probability as the most likely transmission sequence. The Viterbi algorithm used here is a commonly used implementation method that can complete this task while keeping the complexity relatively low. Let \(\mathbf{s}_i) denote the state vector of the i-th path, and \(\mathbf{p}(\mathbf{s}_i)) be its corresponding probability density function. Then, according to Bayes' theorem, the probability of each update step can be expressed as: \[\mathbf{p}(\mathbf{s}_{i+1}|\mathbf{r}) =\frac{\mathbf{p}(\mathbf{r}|\mathbf{s}_{i+1})\mathbf{p}(\mathbf{s}_{i+1})} {\sum_{j=1}^{N}\mathbf{p}(\mathbf{r}|\mathbf{s}_j)\mathbf{p}(\mathbf{s}_j)} ] Where \(\mathbf{r}) represents the observed received signal sequence, and N is the number of all possible states; by iteratively executing the above steps until the entire data frame has been traversed, the most likely transmission sequence is finally determined. S4. High-speed clock synchronization is achieved by embedding a clock signal or using a CDR circuit. S5. Each MicroLED channel is equipped with an independent data transmission line and control signal line. In order to achieve a higher total bandwidth, the independent MicroLED channels are synchronized first to ensure that all channels can receive or send data at the same time.

[0013] Preferably, step S1 includes the following steps: S11. Convolutional layers are used to extract local features from the input signal, pooling layers are used to reduce the number of parameters and control overfitting, and ReLU linear rectified units are selected as the activation function to enhance the nonlinear expressive power of the model and capture the spatial correlation of the signal in the time-frequency domain. Subsequently, the feature map is sampled through pooling layers, thereby reducing the number of network parameters, reducing computational complexity, effectively suppressing overfitting, and improving the generalization ability of the model. S12. During model training, the training data comes from publicly available datasets and undergoes standardized preprocessing to ensure that all samples have the same scale. The loss function is designed as cross-entropy loss, and the algorithm is optimized by the Adam optimizer, which can effectively accelerate the convergence speed while avoiding local optima. S13. Regarding the selection of hyperparameters, the learning rate was initially set to 0.001, the batch size to 32, and the number of iterations to 50 rounds. These parameters were determined to be the optimal combination based on multiple experiments, ensuring that the model neither overfits nor underfits during training. S14. Signal extraction also uses two modulation methods, OOK and PAM4. For OOK modulation, the carrier is transmitted when the input signal is logic '1', otherwise it is not transmitted. For PAM4, the amplitude levels of the transmitted signal are adjusted according to the different states of the input signal. Specifically, assuming the input signal x(t), the corresponding OOK modulated signal s_ook(t) can be expressed as s_ook(t) = A*x(t), where A represents the carrier amplitude. The PAM4 modulated signal s_pam4(t) is mapped to one of {-3A, -A, A, 3A} according to the value of x(t).

[0014] Preferably, step S4 includes the following steps: S41. When selecting embedded clock technology, clock information is encoded into the data stream so that the receiver can directly extract the clock signal for synchronization from the received data sequence. For application scenarios based on the 8b / 10b encoding scheme, each character is mapped to a ten-bit codeword, which contains enough transitions to ensure that the clock can be recovered from the data stream. When using a clock recovery function (CDR), the input data signal undergoes preprocessing, including amplification and filtering, to improve the signal-to-noise ratio and reduce interference. Then, the signal is sent to a phase detector and compared with a reference clock generated by a local oscillator. The local clock frequency is adjusted based on the phase difference until the two clocks are synchronized. Key parameters involved in this process include: \(f_{in}) as the input signal frequency, \(f_{ref}) as the reference clock frequency, and \(Delta f) as the frequency deviation. \(f_{in}) refers to the actual frequency of the clock signal to be recovered; \(f_{ref}) is the ideal operating frequency set by the system; and \(Delta f = f_{in} - f_{ref}) represents the difference between the actual frequency and the ideal value at the current moment. Effective control of these variables allows for high-precision time synchronization.

[0015] Preferably, step S5 includes the following steps: S51. During the MicroLED synchronization process, a precise time reference is provided to all MicroLED channels through a central clock signal source. In addition, a main controller is set up to manage the entire bonding system, which includes, but is not limited to, data allocation, error detection and correction. S52. When the external data stream enters the system, the main controller will divide the large data packet into several small data packets according to the preset algorithm and distribute them evenly to each available MicroLED channel for parallel transmission. In this process, in order to ensure data integrity and transmission efficiency, LDPC low-density parity check code is used to enhance anti-interference capability. The receiving end is equipped with a corresponding decoder and merging unit to recover the original information. The decoder is responsible for decoding the data received from each MicroLED channel; while the merging unit is responsible for recombining these scattered small data packets into complete large data packets. Through the above mechanism, multiple MicroLED channels can be effectively utilized to achieve high-speed data transmission, thereby significantly improving the performance of the overall communication system.

[0016] The beneficial effects of this invention are as follows: 1. The present invention provides a parallel optical signal modulation and demodulation method and system based on MicroLED array optical interconnection, with a high-speed DSP + MicroLED channel overall architecture: breaking the traditional idea of ​​"hundreds of channels, no DSP, wide but slow", by introducing SerDes and DSP modulation and demodulation, the single channel rate is increased by an order of magnitude, thereby achieving a total bandwidth of ≥120Gbps with ≤32 channels; 2. The present invention provides a parallel optical signal modulation and demodulation method and system based on MicroLED array optical interconnection, and simultaneously performs single-channel 10–20Gbps OOK / PAM4 modulation: clearly defines the high-order modulation of MicroLED under GHz-level bandwidth conditions, overcomes the carrier lifetime limitation of MicroLED, and ensures low bit error rate through pre-emphasis, equalization, and FEC. 3. The parallel optical signal modulation and demodulation method and system based on MicroLED array optical interconnection described in this invention utilizes simplified optical coupling, which reduces the number of channels while directly bringing about relaxed alignment tolerances between microlenses / fibers and MicroLED arrays, improved packaging yield, and reduced costs—forming a "structure-effect" advantage that is significantly different from existing technologies. 4. The present invention provides a parallel optical signal modulation and demodulation method and system based on MicroLED array optical interconnect. The low-power DSP solution can achieve 15Gbps with a power budget of ≤1pJ / bit, which solves the prejudice that "introducing DSP will increase power consumption". This allows both high speed and low power consumption to be achieved in MicroLED optical interconnect.

[0017] 5. The parallel optical signal modulation and demodulation method and system based on MicroLED array optical interconnection described in this invention utilizes scalable channel bonding, supports N×15Gbps aggregation, and the protection scope is not limited to a fixed number of channels, leaving room for future multi-channel SiP or SoC integration. Attached Figure Description

[0018] The invention will now be further described with reference to the accompanying drawings.

[0019] Figure 1 This is a detailed overall structural view of the present invention; Figure 2 This is a schematic diagram of the specific structure in this invention; Figure 3 This is a schematic diagram illustrating the working principle and interaction of each part in the first state of the present invention; Figure 4 This is a schematic diagram illustrating the behavioral characteristics of the second type of state system in this invention. Detailed Implementation

[0020] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments. Example

[0021] like Figures 1 to 2 As shown in the embodiment of the present invention, a parallel optical signal modulation and demodulation system based on MicroLED array optical interconnect includes: The data acquisition module is used to acquire raw data from the external environment or equipment and convert it into a form suitable for subsequent processing. The data acquisition module and the data processing module exchange data using a high-speed serial communication protocol, enabling data to be quickly transmitted to the next stage. The data processing module is used to receive information from the data acquisition module and preprocess it. The data processing module is used to remove noise from the data collected by the data acquisition module. The processed data will be sent to the data analysis module for data analysis and processing. The data analysis module uses advanced algorithms to perform in-depth analysis of the received data and extract valuable information or patterns. The data analysis results are transmitted to the control decision module for control decision processing. The control decision module is used to formulate corresponding strategies or instructions based on the received data analysis reports and to provide feedback to users through the user interface. The user interface is used for two-way communication with the control decision module; The user interface includes a data transmission unit and a data receiving unit. The data transmission unit converts the collected parallel data into a high-speed serial data stream using SerDes; then, it encodes and modulates the serial data using a DSP; and drives a designated channel in the MicroLED array to emit light. The data receiving unit uses a photodetector to map the light-emitting channels inside the MicroLED and receives the light signals from inside the MicroLED; subsequently, the DSP samples, decides, and decodes the received light signals; and finally, SerDes restores the serial data to the original parallel data. Example

[0022] like Figures 3 to 4 As shown in the figure, a parallel optical signal modulation and demodulation method based on MicroLED array optical interconnection according to an embodiment of the present invention includes the following steps: Includes the following steps: S1. It adopts a deep convolutional neural network as the core model architecture, which mainly consists of an input layer, multiple hidden layers, convolutional layers, pooling layers, and an output layer. It mainly achieves high-precision signal processing through hierarchical data extraction. S1 includes the following steps: S11. Convolutional layers are used to extract local features from the input signal, pooling layers are used to reduce the number of parameters and control overfitting, and ReLU linear rectified units are selected as the activation function to enhance the nonlinear expressive power of the model and capture the spatial correlation of the signal in the time-frequency domain. Subsequently, the feature map is sampled through pooling layers, thereby reducing the number of network parameters, reducing computational complexity, effectively suppressing overfitting, and improving the generalization ability of the model. S12. During model training, the training data comes from publicly available datasets and undergoes standardized preprocessing to ensure that all samples have the same scale. The loss function is designed as cross-entropy loss, and the algorithm is optimized by the Adam optimizer, which can effectively accelerate the convergence speed while avoiding local optima. S13. Regarding the selection of hyperparameters, the learning rate was initially set to 0.001, the batch size to 32, and the number of iterations to 50 rounds. These parameters were determined to be the optimal combination based on multiple experiments, ensuring that the model neither overfits nor underfits during training. S14. Signal extraction also uses two modulation methods, OOK and PAM4. For OOK modulation, a carrier wave is transmitted when the input signal is logic '1', otherwise no signal is transmitted. For PAM4, the four different amplitude levels of the transmitted signal are adjusted according to the different states of the input signal. S2. Use LDPC low-density parity-check code or FEC forward error correction code to improve data transmission reliability; S3. At the receiving end, DFE decision feedback equalization or MLSE maximum likelihood sequence estimation algorithm is used to compensate for channel distortion. These algorithms can effectively reduce signal distortion caused by channel characteristics, thereby improving the performance of the communication system. S4. High-speed clock synchronization is achieved by embedding a clock signal or using a CDR circuit. S4 includes the following steps: S41. When selecting embedded clock technology, clock information is encoded into the data stream so that the receiver can directly extract the clock signal for synchronization from the received data sequence. For application scenarios based on the 8b / 10b encoding scheme, each character is mapped to a ten-bit codeword, which contains enough transitions to ensure that the clock can be recovered from the data stream. S5. Each MicroLED channel is equipped with an independent data transmission line and control signal line. In order to achieve a higher total bandwidth, the independent MicroLED channels are synchronized first to ensure that all channels can receive or send data at the same time. S5 includes the following steps: S51. During the MicroLED synchronization process, a precise time reference is provided to all MicroLED channels through a central clock signal source. In addition, a main controller is set up to manage the entire bonding system, which includes, but is not limited to, data allocation, error detection and correction. S52. When the external data stream enters the system, the main controller will divide the large data packet into several small data packets according to the preset algorithm and distribute them evenly to each available MicroLED channel for parallel transmission. In this process, in order to ensure data integrity and transmission efficiency, LDPC low-density parity check code is used to enhance anti-interference capability.

[0023] Working principle: The overall architecture of high-speed DSP + MicroLED channel: Breaking the traditional idea of ​​"hundreds of channels, no DSP, wide but slow", by introducing SerDes and DSP modulation and demodulation, the single channel rate is increased by an order of magnitude, thereby achieving a total bandwidth of ≥120Gbps with ≤32 channels; Simultaneously, single-channel 10–20Gbps OOK / PAM4 modulation: clearly defines the high-order modulation of MicroLED under GHz-level bandwidth conditions, overcomes the carrier lifetime limitation of MicroLED, and ensures low bit error rate through pre-emphasis, equalization, and FEC; By simplifying optical coupling, the number of channels can be reduced while simultaneously allowing for more relaxed alignment tolerances between the microlens / fiber and the MicroLED array, improved packaging yield, and lower costs—forming a "structure-effect" advantage that is significantly different from existing technologies. The low-power DSP solution can achieve 15Gbps with a power budget of ≤1pJ / bit, which solves the prejudice that "introducing DSP will increase power consumption" and allows high speed and low power consumption to be achieved in MicroLED optical interconnects.

[0024] With scalable channel bonding, it supports N×15Gbps aggregation, and the protection range is not limited to a fixed number of channels, leaving room for future multi-channel SiP or SoC integration.

[0025] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A parallel optical signal modulation and demodulation system based on MicroLED array optical interconnect, characterized in that: include: The data acquisition module is used to acquire raw data from the external environment or equipment and convert it into a form suitable for subsequent processing. The data processing module is used to receive information from the data acquisition module and preprocess it. The data analysis module uses advanced algorithms to perform in-depth analysis of the received data and extract valuable information or patterns. The control decision module is used to formulate corresponding strategies or instructions based on the received data analysis reports and to provide feedback to users through the user interface. The user interface is used for two-way communication with the control decision module.

2. The parallel optical signal modulation and demodulation system based on MicroLED array optical interconnection according to claim 1, characterized in that: The data acquisition module and the data processing module exchange data using a high-speed serial communication protocol, enabling data to be quickly transmitted to the next stage.

3. The parallel optical signal modulation and demodulation system based on MicroLED array optical interconnection according to claim 1, characterized in that: The data processing module is used to remove noise from the data collected by the data acquisition module. The processed data will then be sent to the data analysis module for further analysis.

4. The parallel optical signal modulation and demodulation system based on MicroLED array optical interconnection according to claim 1, characterized in that: The data analysis results are transmitted to the control decision module for control decision processing.

5. A parallel optical signal modulation and demodulation system based on MicroLED array optical interconnection according to claim 1, characterized in that: The user interface is equipped with a data transmission unit and a data receiving unit. The data transmission unit converts the collected parallel data into a high-speed serial data stream through SerDes. The serial data is then encoded and modulated by a DSP, and the designated channels in the MicroLED array are driven to emit light.

6. The parallel optical signal modulation and demodulation system based on MicroLED array optical interconnection according to claim 1, characterized in that: The data receiving unit uses a photodetector to array the light-emitting channels inside the MicroLED and receives the light signals inside the MicroLED; subsequently, the received light signals are sampled, decided, and decoded by a DSP; and finally, the serial data is restored to the original parallel data by a SerDes.

7. A parallel optical signal modulation and demodulation method based on MicroLED array optical interconnect, characterized in that: Includes the following steps: S1. It adopts a deep convolutional neural network as the core model architecture, which mainly consists of an input layer, multiple hidden layers, convolutional layers, pooling layers, and an output layer. It mainly achieves high-precision signal processing through hierarchical data extraction. S2. Use LDPC low-density parity-check code or FEC forward error correction code to improve data transmission reliability; S3. At the receiving end, DFE decision feedback equalization or MLSE maximum likelihood sequence estimation algorithm is used to compensate for channel distortion. These algorithms can effectively reduce signal distortion caused by channel characteristics, thereby improving the performance of the communication system. S4. High-speed clock synchronization is achieved by embedding a clock signal or using a CDR circuit. S5. Each MicroLED channel is equipped with an independent data transmission line and control signal line. In order to achieve a higher total bandwidth, the independent MicroLED channels are synchronized first to ensure that all channels can receive or send data at the same time.

8. The parallel optical signal modulation and demodulation method based on MicroLED array optical interconnect according to claim 1, characterized in that: S1 includes the following steps: S11. Convolutional layers are used to extract local features from the input signal, pooling layers are used to reduce the number of parameters and control the fitting phenomenon, and ReLU linear rectified units are selected as the activation function to enhance the nonlinear expressive power of the model and capture the spatial correlation of the signal in the time and frequency domain. Subsequently, the feature map is sampled through a pooling layer, thereby reducing the number of network parameters, reducing computational complexity, effectively suppressing overfitting, and improving the model's generalization ability. S12. During model training, the training data comes from publicly available datasets and undergoes standardized preprocessing to ensure that all samples have the same scale. The loss function is designed as cross-entropy loss, and the algorithm is optimized by the Adam optimizer, which can effectively accelerate the convergence speed while avoiding local optima. S13. Regarding the selection of hyperparameters, the learning rate was initially set to 0.001, the batch size to 32, and the number of iterations to 50 rounds. These parameters were determined to be the optimal combination based on multiple experiments, ensuring that the model neither overfits nor underfits during training. S14. Signal extraction also uses two modulation methods, OOK and PAM4. For OOK modulation, a carrier wave is transmitted when the input signal is logic '1', otherwise no signal is transmitted. For PAM4, the four different amplitude levels of the transmitted signal are adjusted according to the different states of the input signal.

9. A parallel optical signal modulation and demodulation method based on MicroLED array optical interconnect according to claim 1, characterized in that: S4 includes the following steps: S41. When selecting embedded clock technology, clock information is encoded into the data stream so that the receiver can directly extract the clock signal for synchronization from the received data sequence. For application scenarios based on the 8b / 10b encoding scheme, each character is mapped to a ten-bit codeword, which contains enough transitions to ensure that the clock can be recovered from the data stream.

10. A parallel optical signal modulation and demodulation method based on MicroLED array optical interconnect according to claim 1, characterized in that: S5 includes the following steps: S51. During the MicroLED synchronization process, a precise time reference is provided to all MicroLED channels through a central clock signal source. In addition, a main controller is set up to manage the entire bonding system, which includes, but is not limited to, data allocation, error detection and correction. S52. When the external data stream enters the system, the main controller will divide the large data packet into several small data packets according to the preset algorithm and distribute them evenly to each available MicroLED channel for parallel transmission. In this process, in order to ensure data integrity and transmission efficiency, LDPC low-density parity check code is used to enhance anti-interference capability.

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