A coding and decoding method for earthquake early warning encrypted transmission

Abstract

The present invention relates to the field of communication technology, and more specifically, to a coding and decoding method for encrypted transmission of earthquake early warning, comprising: obtaining an original earthquake monitoring signal; obtaining transmission channel characteristic parameters; generating a differential baseline signal by adopting a differential delay method based on the obtained I-channel and Q-channel signals; calculating a distortion compensation coefficient according to phase and amplitude changes of the signal to generate a compensated baseline signal; based on the compensated I-channel and Q-channel signals, adopting orthogonal amplitude modulation QAM to perform signal modulation; performing pseudo-random sequence encryption processing on the modulated signal to generate an encrypted earthquake early warning signal; obtaining transmission channel characteristic parameters, adjusting the amplitude and phase of a receiving end signal in real time by using an adaptive equalizer, and correcting signal distortion generated during transmission; sending the encrypted earthquake early warning signal to a receiving end; restoring the original signal by using a decryption algorithm based on the signal after equalization processing; outputting earthquake early warning information, and significantly improving signal integrity.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and more specifically, to a coding and decoding method for earthquake early warning encrypted transmission. Background Art

[0002] As an important technology for disaster prevention and mitigation in modern society, earthquake early warning system aims to use the time difference of seismic wave propagation to gain valuable emergency response time for the target area. At present, the data collection, processing and transmission technology in earthquake early warning system has achieved great development, but there are still problems such as insufficient signal integrity, low transmission security, poor real-time performance and limited anti-interference ability. In order to better understand the limitations of the prior art and the technical contribution of the present invention, the following is a detailed analysis combined with the closest prior art.

[0003] In the paper “Earthquake Early Warning System by IoT Using Wireless Sensor Networks” (pages 1201-1205) published by A. Alphonsa and G. Ravi at the 2016 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET), an earthquake early warning system based on wireless sensor networks (WSN) was proposed. The paper describes an implementation scheme that transmits sensor data of seismic waves through the Zigbee protocol, transmits it to the gateway, and then sends it to the user end. Although this method has the advantages of low deployment cost and is suitable for distributed monitoring, the low-speed transmission characteristics of Zigbee significantly limit the real-time performance of the system, and the scheme lacks a dynamic compensation mechanism for channel noise and multipath interference, resulting in a high data packet loss rate and difficulty in ensuring signal integrity.

[0004] Kaifeng Wang et al. studied an earthquake early warning data transmission method based on cell broadcast short messages (CBS) in the paper "Wireless Data Transmission Method of Earthquake Early Warning Information in High-Speed ​​Railway" (pages 117-121) published at the 2019 Chinese Automation Congress (CAC) in 2019. This method combines packet switching and redundant transmission technology, especially for the special needs of high-speed moving objects in high-speed rail scenarios. However, the scheme has insufficient compensation mechanism for signals, performs poorly in harsh channel environments, and the signal recovery rate drops significantly. In addition, due to the use of a fixed channel mapping strategy, the security and anti-interference of signal transmission are difficult to meet actual needs.

[0005] Wenjun Wang and Shun Yang’s paper “Study of the TDM of the GPS Timing in Earthquake Early-Warning Information Transfer” published at the 2010 International Conference on Intelligent Computation Technology and Automation (Volume 3, Pages 455-457) proposed a method for earthquake early warning data transmission using GPS timing technology and time division multiplexing (TDM). The paper proposed that point-to-point data transmission over a single-frequency radio channel can improve time synchronization accuracy. However, this method is highly dependent on a single channel, and the transmission performance is greatly reduced in the face of multipath interference and signal distortion, and it lacks adaptability and flexibility.

[0006] By analyzing the above documents, the prior art has the following technical problems:

[0007] 1. Insufficient signal distortion and integrity: Existing technologies generally lack effective dynamic compensation mechanisms to combat channel distortion and noise. For example, the transmission characteristics of Zigbee result in data integrity being heavily dependent on an ideal channel environment. Once channel noise increases, the signal bit error rate (BER) will increase significantly.

[0008] 2. Insufficient encryption and security: Kaifeng Wang et al.’s cell broadcast short message solution lacks dynamic encryption and decryption strategies and only relies on static channel mapping, which is easily cracked and cannot cope with complex channel attacks.

[0009] 3. Poor real-time performance: In the method proposed by Wenjun Wang et al., due to the fixed time slot characteristics of TDM, the end-to-end delay of signal transmission is high and cannot meet the millisecond-level warning requirements.

[0010] 4. Limited anti-interference performance: The existing technology has insufficient anti-interference capabilities. For example, in Wenjun Wang’s research, channel multipath interference in high-speed railway scenarios significantly reduced the signal recovery rate and affected the effectiveness of the warning signal. Summary of the invention

[0011] In view of the above problems existing in the prior art, the present invention proposes a coding and decoding method for encrypted transmission of earthquake early warning. Specifically, the present invention solves the following technical problems: by dynamically adjusting the compensation coefficient and the adaptive equalizer, the accuracy of signal restoration is significantly improved, and a low bit error rate can be maintained even in a complex channel environment; by using pseudo-random encryption and reverse mapping mechanisms, the signal transmission has a high anti-attack capability, ensuring the confidentiality and integrity of the data; by combining efficient coding algorithms and low-latency transmission protocols, the transmission delay of earthquake early warning signals is controlled at the millisecond level to meet the needs of emergency response; through multi-level equalization processing and channel dynamic analysis, the method of the present invention can significantly improve the signal recovery rate under complex interference conditions and enhance the robustness of the system.

[0012] The present invention provides a coding and decoding method for earthquake early warning encrypted transmission, comprising:

[0013] Obtaining the original seismic monitoring signal, and collecting seismic wave information including I-channel and Q-channel baseline signals through a sensor array arranged in the target area, wherein the I-channel and Q-channel signals represent the real part and imaginary part of the orthogonal baseline signal respectively;

[0014] Obtain transmission channel characteristic parameters, including channel noise, distortion and multipath effect characteristics, as reference data for subsequent processing;

[0015] Based on the acquired I-channel and Q-channel signals, a differential baseline signal is generated by using a differential delay method;

[0016] Calculate the distortion compensation coefficient according to the phase and amplitude changes of the signal , and through the compensation formula and , generates a compensated baseline signal; where, is the compensated I-channel signal, is the compensated Q-path signal, is the amplitude compensation coefficient, is the phase compensation coefficient;

[0017] Based on the compensated I-channel and Q-channel signals, quadrature amplitude modulation (QAM) is used for signal modulation;

[0018] Perform pseudo-random sequence encryption processing on the modulated signal to generate an encrypted earthquake early warning signal;

[0019] Obtain the characteristic parameters of the transmission channel, use the adaptive equalizer to adjust the amplitude and phase of the receiving end signal in real time, and correct the signal distortion generated during transmission;

[0020] Sending the encrypted earthquake warning signal to the receiving end via wireless or wired communication;

[0021] At the receiving end, the original signal is restored using a decryption algorithm based on the equalized signal;

[0022] Output earthquake warning information, including epicenter location, magnitude and warning time, to provide efficient and reliable earthquake warning services for the target area.

[0023] Preferably, the distortion compensation process specifically includes:

[0024] Calculate the change direction of the phase and amplitude of the I-channel and Q-channel signals respectively;

[0025] Dynamically adjust the value range of the compensation coefficient based on the amplitude difference , to achieve adaptive compensation in different channel environments.

[0026] Preferably, the encryption process specifically includes:

[0027] Scramble the constellation points of the QAM modulated signal using a pseudo-random sequence;

[0028] A reverse mapping mechanism based on a predefined mapping table is adopted to ensure the symmetry between the encrypted signal and the decrypted signal.

[0029] Preferably, the channel equalization processing specifically includes:

[0030] A multi-stage equalizer is used to gradually adjust the received signal. The primary equalizer is used to filter out high-frequency noise, and the secondary equalizer is used to restore the signal amplitude.

[0031] Preferably, the compensation coefficient The range is [0.1,1.0], the compensation coefficient The range is [0.05, 0.8], and the specific value is dynamically adjusted according to the channel noise.

[0032] Preferably, the layout of the sensor array includes:

[0033] For shallow earthquakes with focal depths less than 10 km, the sensor spacing should not exceed 2 km;

[0034] For deep earthquakes, the sensor spacing is appropriately relaxed to 5 kilometers.

[0035] As a preference, it also includes:

[0036] Output the seismic wave signal strength curve in real time through the receiving end display device;

[0037] Automatically trigger the disaster prevention and mitigation control system to initiate emergency response.

[0038] Preferably, the transmission method of the encrypted signal includes:

[0039] Wireless communication is achieved through Zigbee, LoRa or 5G technology;

[0040] Wired communication is achieved through fiber optic networks.

[0041] Preferably, the reverse mapping mechanism includes:

[0042] Matching the encrypted constellation points with the decrypted constellation points by table lookup;

[0043] When the table lookup error exceeds the preset threshold, the resynchronization mechanism is automatically triggered.

[0044] Preferably, the output form of the earthquake early warning information includes:

[0045] Push real-time alerts via mobile devices;

[0046] Generate a map of the affected area based on the epicenter location.

[0047] The beneficial effects of the present invention are mainly reflected in the following aspects:

[0048] 1. The signal integrity is significantly improved: the method of the present invention maintains an extremely low bit error rate under channel distortion conditions and effectively restores the signal integrity;

[0049] 2. Greatly improved security: The combination of pseudo-random encryption and dynamic compensation significantly enhances the security of data transmission and prevents the possibility of malicious decryption;

[0050] 3. Real-time performance meets early warning requirements: Through efficient transmission protocols, the method of the present invention can reduce end-to-end delay to less than 2 milliseconds;

[0051] 4. Optimization of anti-interference performance: The signal recovery rate of the method of the present invention in a multipath interference environment reaches over 98%, which is much higher than the level of the prior art.

[0052] By solving these problems in the prior art, the method of the present invention significantly improves the reliability and effectiveness of the earthquake early warning system in actual application scenarios, and has important technical value and application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 The figure is a flow chart of the method of the present invention.

[0054] Figure 2 This is the core logic block diagram of the signal processing of the present invention.

[0055] Figure 3 This is the encryption and decryption logic block diagram of the present invention.

[0056] Figure 4 This is a logic block diagram for outputting early warning information of the present invention. DETAILED DESCRIPTION

[0057] Please refer to Figure 1-4 The present invention provides a coding and decoding method for earthquake early warning encrypted transmission, comprising the following steps:

[0058] Get the original seismic monitoring signal, including I-channel signal and road signal ,Collect seismic wave information through sensor arrays deployed in the target area;

[0059] Obtain channel characteristic parameters, including channel noise , distortion level and multipath effect characteristics .

[0060] Based on the acquired I-channel and Q-channel signals, a differential baseline signal is generated by using a differential delay method;

[0061] According to the amplitude of the signal and Phase , calculate the distortion compensation coefficient , and according to the formula

[0062] ,and ,

[0063] Generate a compensated baseline signal where is the compensated I-channel signal, is the compensated Q-path signal, is the amplitude compensation coefficient, is the phase compensation coefficient;

[0064] The compensated signal is input into the encoder and modulated using quadrature amplitude modulation (QAM).

[0065] Transmitting the encrypted earthquake warning signal to a receiving end through a communication channel;

[0066] At the receiving end, a decoding algorithm is used to restore the compensated baseline signal and generate earthquake warning information.

[0067] Preferably, the accuracy of seismic signal acquisition is improved by multi-sensor fusion technology, for example, the spacing of the sensor array is preferably 2 kilometers to ensure sufficient spatial resolution. For the acquisition of channel characteristic parameters, it is preferred to analyze the channel environmental noise in real time, and the empirical value The range should be 10dB to 50dB to adapt to various transmission environments.

[0068] In the processing step, the baseline signal generated by the differential delay method can effectively enhance the time correlation of the signal, which is beneficial to the calculation of the subsequent compensation coefficient. Preferably, the calculation formula of the compensation coefficient is as follows:

[0069] ,

[0070] ,

[0071] in and are the maximum amplitudes of the I and Q signals respectively. and are the phases of the I and Q signals respectively. Empirical values ​​show that under multipath effects In strong cases, the compensation coefficient range Yiwei .

[0072] In the output step, signal transmission is preferably performed through 5G communication technology to reduce transmission delay and ensure that earthquake warning information can be generated in real time before the arrival of seismic waves. Specifically, the transmission delay should be controlled within 1ms to meet emergency response needs.

[0073] In a specific embodiment of the present invention, the distortion compensation process specifically includes:

[0074] Calculate the change direction of phase and amplitude of I and Q signals respectively; dynamically adjust the value range of compensation coefficient based on amplitude difference , to achieve adaptive compensation in different channel environments.

[0075] Preferably, in one embodiment of the present invention, the direction of change of phase and amplitude is calculated by the following formula:

[0076]

[0077]

[0078] in is the phase change, is the amplitude change, and are the phase values ​​at adjacent sampling moments, and are the amplitude values ​​at adjacent sampling moments respectively.

[0079] For dynamic adjustment of the compensation coefficient, preferably, the initial value of the compensation coefficient is determined by a table lookup method. 20dB and multipath effect In the case of When the channel environment changes, the compensation coefficient is updated using the following formula:

[0080] ,

[0081] ,

[0082] in and is the adaptive adjustment factor, and the empirical value range is .

[0083] The method of the present invention is preferably combined with the above formula, and real-time adjustment is achieved through an adaptive equalizer, which can significantly improve the accuracy of distortion compensation and effectively reduce the impact of channel interference on data transmission.

[0084] In a specific embodiment of the present invention, the encryption process specifically includes:

[0085] Scramble the constellation points of the QAM modulated signal using a pseudo-random sequence;

[0086] A reverse mapping mechanism based on a predefined mapping table is adopted to ensure the symmetry between the encrypted signal and the decrypted signal.

[0087] Preferably, in one embodiment of the present invention, the generation of the pseudo-random sequence adopts a linear feedback shift register (LFSR) algorithm, and the period of the pseudo-random sequence is ,in For the number of bits in the register, it is recommended to select To ensure the security of the sequence. The scrambling process is achieved through the following formula:

[0088] ,

[0089] in is the scrambled signal, is the original signal, is a pseudo-random sequence, Represents a bitwise exclusive-or operation.

[0090] During the decryption process, by comparing the pseudo-random sequence The reverse XOR operation restores the original signal Preferably, to ensure the symmetry of the mapping process, the following reverse mapping table is used:

[0091] ,

[0092] ,

[0093] in is the mapping function, is its inverse function.

[0094] Through the above encryption and decryption processing, the method of the present invention can effectively prevent the transmission data from being illegally stolen while maintaining the integrity and efficiency of the data.

[0095] In a specific embodiment of the present invention, the channel equalization processing specifically includes: using a multi-stage equalizer to gradually adjust the received signal; the primary equalizer is used to filter out high-frequency noise, and the secondary equalizer is used to restore the signal amplitude.

[0096] In the embodiment of the present invention, the channel equalization processing is gradually optimized by a multi-stage equalizer. Preferably, the primary equalizer is mainly used to pre-process the received signal to weaken the influence of high-frequency noise and multipath interference. In the noise component It can be filtered out by the following formula:

[0097] ,

[0098] in, is the filtered signal, and LPF() represents the low-pass filtering operation. The secondary equalizer is used to further restore the signal amplitude and adjust the dynamic range of the signal by amplitude normalization. For example, the normalized signal amplitude It can be expressed as:

[0099] ,

[0100] in is the original signal amplitude, is the maximum amplitude of the signal.

[0101] Preferably, the method of the present invention is combined with an adaptive filter to further optimize the equalizer performance, and the filter coefficients are dynamically adjusted according to the real-time characteristics of the input signal, which effectively improves the accuracy and robustness of signal restoration.

[0102] In a specific embodiment of the present invention, the compensation coefficient The range is [0.1,1.0], the compensation coefficient The range is [0.05, 0.8], and the specific value is dynamically adjusted according to the channel noise.

[0103] In a preferred embodiment of the present invention, the range of the compensation coefficient is set according to the complexity of the channel environment. dB, experience shows that Can effectively reduce signal distortion and restore signal integrity.

[0104] In order to further adapt to complex channel environments, the method of the present invention calculates the compensation coefficient through the following dynamic adjustment formula:

[0105] ,

[0106] ,

[0107] in and is the compensation coefficient after dynamic adjustment, is the multipath interference factor, and the empirical value should be controlled within 0.5.

[0108] Preferably, the method of the present invention is combined with a table lookup method to quickly obtain the initial compensation parameters. For example, when dB and When This dynamic adjustment mechanism significantly improves the adaptability and stability of signal compensation.

[0109] In a specific embodiment of the present invention, the layout of the sensor array includes:

[0110] For shallow earthquakes with focal depths less than 10 km, the sensor spacing should not exceed 2 km;

[0111] For deep earthquakes, the sensor spacing is appropriately relaxed to 5 kilometers.

[0112] In a preferred embodiment of the present invention, the layout of the sensor array is optimized according to the focal depth to ensure accurate capture and real-time transmission of seismic signals. Preferably, for shallow earthquakes, the spacing is controlled within 2 kilometers, which can significantly improve the spatial resolution and capture more delicate seismic wave information.

[0113] In the monitoring scenario of deep earthquakes, expanding the sensor spacing to 5 kilometers can reduce deployment costs while maintaining high signal capture efficiency. Experience shows that when the source depth is 20 kilometers, this configuration can control the signal loss rate to less than 1%.

[0114] In addition, each sensor in the sensor array preferably adopts a high-sensitivity accelerometer, whose sensitivity should be greater than 10m / s², which can effectively capture the early signals of P waves and S waves and provide reliable data support for the efficient processing of earthquake early warning information.

[0115] In a preferred embodiment of the present invention, it further comprises:

[0116] Output the seismic wave signal strength curve in real time through the receiving end display device;

[0117] Automatically trigger the disaster prevention and mitigation control system to initiate emergency response.

[0118] In the method of the present invention, preferably, the seismic wave signal strength curve is visualized in real time by a receiving end display device, and the display content includes the epicenter position, magnitude and warning time. For example, the epicenter position is calculated by the following formula:

[0119] ,

[0120] in is the distance between the epicenter and the monitoring point, and are the coordinates of the epicenter and monitoring point, respectively.

[0121] In addition, the method of the present invention is preferably combined with an emergency response system to achieve automated processing, such as When an earthquake occurs, the control system is triggered to start the emergency cut-off mechanism of electricity, gas and traffic to ensure the safety of personnel and property. This emergency threshold is determined based on the analysis of historical earthquake data and can effectively balance the response speed and false alarm rate.

[0122] In the embodiment of the present invention, through the above display and triggering steps, not only the readability of the warning information is improved, but also the time from signal collection to emergency response is significantly shortened.

[0123] In an embodiment of the present invention, the transmission method of the encrypted signal includes:

[0124] Wireless communication is achieved through Zigbee, LoRa or 5G technology; wired communication is achieved through fiber optic networks.

[0125] In the embodiments of the present invention, in order to ensure efficient transmission of encrypted signals, multiple communication methods are preferably used to meet the needs of different scenarios. Among wireless communication methods, Zigbee technology is suitable for short-distance and low-power scenarios, and its transmission distance is preferably within the range of 100 meters to 300 meters, which is suitable for areas where sensors are densely deployed; LoRa technology has the characteristics of long distance and low rate, and is suitable for seismic signal transmission within a range of 2 kilometers to 10 kilometers.

[0126] In scenarios where extremely low latency is required, 5G technology is preferred, as its end-to-end latency can be as low as 1 millisecond, enabling rapid transmission of warning signals to the target area. Experiments have shown that in actual deployment, 5G technology is better than traditional wireless communication technology in terms of latency optimization between the epicenter and the receiving end.

[0127] For wired communication, the method of the present invention preferably uses an optical fiber network for signal transmission. The optical fiber network has a large bandwidth and strong anti-interference ability, and is particularly suitable for the transmission of core warning signals in earthquake-prone areas. For example, when the transmission distance exceeds 50 kilometers, optical fiber communication can effectively avoid multipath interference and ensure signal stability.

[0128] By combining the above-mentioned wireless and wired communication methods, the method of the present invention can flexibly adapt to different environmental requirements while ensuring signal stability and low latency.

[0129] The reverse mapping mechanism includes:

[0130] Matching the encrypted constellation points with the decrypted constellation points by table lookup;

[0131] When the table lookup error exceeds the preset threshold, the resynchronization mechanism is automatically triggered.

[0132] In an embodiment of the present invention, a table lookup method is preferably used to achieve efficient matching of encryption constellation points and decryption constellation points. The table lookup method uses a pre-generated constellation point mapping table, which is designed according to the QAM modulation mode and encryption rules. For example, for 16-QAM modulation, the encryption and decryption mapping of constellation points can be defined by the following formula:

[0133] ,

[0134]

[0135] in is the original constellation point, is the encrypted constellation point, and They are the encryption and decryption mapping functions respectively.

[0136] Preferably, when the mapping error rate during the decryption process exceeds 0.5% (empirical values ​​show that this threshold can significantly reduce error propagation), the method of the present invention compensates by automatically triggering a resynchronization mechanism. The resynchronization mechanism includes the following steps:

[0137] Compare the Euclidean distance between the decrypted signal and the compensated signal :

[0138] ,

[0139] in and For the decrypted I and Q signals, and is the original signal;

[0140] like (Preferably, ), then the synchronization mechanism is triggered to update the constellation point mapping table. Through the combination of such reverse mapping and resynchronization, the method of the present invention significantly improves the robustness and reliability of signal decryption, and can maintain efficient data restoration capabilities even under complex channel conditions.

[0141] Through the combination of such reverse mapping and resynchronization, the method of the present invention significantly improves the robustness and reliability of signal decryption, and can maintain efficient data restoration capabilities even under complex channel conditions.

[0142] In an embodiment of the present invention, the output form of the earthquake early warning information includes:

[0143] Push real-time alerts via mobile devices;

[0144] Generate a map of the affected area based on the epicenter location.

[0145] The method of the present invention preferably uses real-time push to send earthquake warning information to users. In an embodiment of the present invention, the warning information includes the epicenter location, magnitude, and expected wave arrival time, etc., which are pushed to the user's mobile device, such as a smart phone, tablet computer, etc. In order to improve the user's understanding of the warning information and the efficiency of responding, the alarm content is preferably displayed through an interactive interface. For example, the magnitude information and warning time It can be expressed as:

[0146] ,

[0147] in is the estimated arrival time of the earthquake wave, The time when the warning information is received.

[0148] In terms of early warning information visualization, in a preferred embodiment of the present invention, a map of the affected area is generated to intuitively display the potential impact range of the earthquake. It can be calculated by the following formula:

[0149] ,

[0150] in is the shock wave propagation speed, The epicenter detection time.

[0151] In addition, the method of the present invention also combines geographic information system (GIS) technology to dynamically mark the affected area, and key facilities such as buildings and roads in the area can be highlighted to assist users in rapid identification and response.

[0152] Through the optimization of the above output form, the method of the present invention can effectively improve the dissemination efficiency of early warning information and the public's risk awareness, and provide reliable technical support for earthquake disaster prevention and mitigation.

[0153] The implementation scheme of the present invention significantly improves the response efficiency and visualization capability of earthquake early warning information while achieving efficient signal transmission and reliable data decryption.

[0154] In order to verify the superiority of the coding and decoding method for earthquake early warning encrypted transmission of the present invention in actual scenarios, a comparative experiment is conducted between Example 1 and two comparative examples. The experiment simulates the transmission process of earthquake early warning signals in a complex channel environment to evaluate signal integrity, transmission delay, security, and anti-interference performance.

[0155] Experimental scenario: simulate a typical earthquake early warning system, where the signal source is located at the epicenter, 10 kilometers away from the receiving end. The signal transmission path includes multipath interference, noise superposition and data encryption transmission.

[0156] Experimental conditions:

[0157] 1. Example 1: The coding and decoding method of earthquake early warning encrypted transmission of the present invention is adopted, combined with a dynamic compensation coefficient adjustment mechanism, pseudo-random encryption, reverse mapping and a multi-level equalizer.

[0158] 2. Comparative Example 1: Using traditional QAM modulation and transmission method, without dynamic compensation mechanism, signal decryption directly uses fixed constellation point mapping.

[0159] 3. Comparative Example 2: A simple scrambling encryption method is used in combination with a single-stage equalization process without a compensation mechanism.

[0160] Test indicators:

[0161] 1. Signal integrity (SI): It is measured by the degree of match between the decoded signal at the receiving end and the original signal. The indicator is expressed in bit error rate (BER). The lower the better.

[0162] 2. Transmission delay (TD): refers to the total time from signal generation to decryption completion at the receiving end, measured in milliseconds (ms). The lower the better.

[0163] 3. Security (SE): measured by the ability to resist malicious decryption and expressed in terms of cracking success rate (CR). The lower the better.

[0164] 4. Anti-interference performance (AI): The signal recovery capability under multipath interference conditions, expressed by the signal recovery rate (SR), the higher the better.

[0165] Detection Methods

[0166] 1. Signal integrity detection: By randomly generating test data, the bit error rate of the receiving end after transmission is calculated. The detection formula is:

[0167] , the total number of bits is 10 6 .

[0168] 2. Transmission delay detection: Use a precise timing instrument to measure the total time from signal generation to decryption completion in milliseconds.

[0169] 3. Security testing: simulate the attack environment, try to crack the constellation point mapping of the pseudo-random sequence, and count the cracking success rate.

[0170] 4. Anti-interference performance test: Under simulated multipath interference conditions, the Euclidean distance recovery algorithm is used to calculate the signal recovery rate. The formula is:

[0171] , the interference intensity is set to 20dB.

[0172] The test results are shown in the following table:

[0173] Detection parameters Example 1 Comparative Example 1 Comparative Example 2 Signal Integrity (BER) <![CDATA[1.2x10 -5 ]]> <![CDATA[5.3x10 -3 ]]> <![CDATA[1.8x10 -3 ]]> Transmission delay (ms) 2.3 4.8 3.6 Safety (CR,%) 0.01 10.3 25.8 Anti-interference performance (SR,%) 98.7 80.2 85.6

[0174] The analysis and explanation are as follows:

[0175] The method of the present invention effectively reduces the distortion in the signal transmission process through the synergistic effect of the dynamic compensation coefficient and the multi-stage equalizer, and achieves an extremely low BER of 1.2x10 -5 , which is better than the results of comparative examples 1 and 2. In comparative example 1, the bit error rate is significantly increased due to the lack of compensation mechanism; although scrambling encryption improves the bit error rate to a certain extent in comparative example 2, the effect of single-stage equalization is limited.

[0176] The method of the present invention preferably uses 5G communication technology and an efficient coding algorithm, so that the transmission delay is only 2.3ms, which is much lower than the delays of Comparative Examples 1 and 2. The low delay feature of the present invention provides a longer emergency response time for the earthquake early warning system.

[0177] Through pseudo-random encryption and reverse mapping mechanism, the method of the present invention significantly improves the difficulty of signal cracking, and the cracking success rate is only 0.01%. Comparative Examples 1 and 2 have 10.3% and 25.8% cracking success rates respectively due to the relatively simple encryption strategy, which makes it difficult to ensure transmission security.

[0178] Under multipath interference conditions, the recovery rate of the method of the present invention is as high as 98.7%, thanks to the efficient cooperation of the dynamic adjustment compensation coefficient and the multi-stage equalizer. Comparative Examples 1 and 2 failed to dynamically adapt to the channel environment, and the recovery rates were 80.2% and 85.6% respectively.

[0179] Based on the above indicators, Example 1 performs well in signal integrity, transmission delay, security and anti-interference performance, and is the best embodiment of the present invention. The test results show that the method of the present invention can achieve low-latency, high-security and high-reliability earthquake warning signal transmission under complex channel conditions, which is significantly better than traditional methods. This further verifies the creativity and practical value of the present invention in earthquake warning scenarios.

[0180] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A coding and decoding method for earthquake early warning encrypted transmission, characterized in that: include: Obtaining the original seismic monitoring signal, and collecting seismic wave information including I-channel and Q-channel baseline signals through a sensor array arranged in the target area, wherein the I-channel and Q-channel signals represent the real part and imaginary part of the orthogonal baseline signal respectively; Obtain transmission channel characteristic parameters, including channel noise, distortion and multipath effect characteristics, as reference data for subsequent processing; Based on the acquired I-channel and Q-channel signals, a differential baseline signal is generated by using a differential delay method; Distortion compensation processing, including: calculating the distortion compensation coefficient according to the phase and amplitude changes of the signal , and through the compensation formula and , generates a compensated baseline signal; where, is the compensated I-channel signal, is the compensated Q-path signal, is the amplitude compensation coefficient, is the phase compensation coefficient; Based on the compensated I-channel and Q-channel signals, quadrature amplitude modulation (QAM) is used for signal modulation; Perform pseudo-random sequence encryption processing on the modulated signal to generate an encrypted earthquake early warning signal; Obtain the characteristic parameters of the transmission channel, use the adaptive equalizer to adjust the amplitude and phase of the receiving end signal in real time, and correct the signal distortion generated during transmission; Sending the encrypted earthquake warning signal to the receiving end via wireless or wired communication; At the receiving end, the original signal is restored using a decryption algorithm based on the equalized signal; Output earthquake warning information, including epicenter location, magnitude, and warning time, to provide efficient and reliable earthquake warning services for target areas; The distortion compensation process specifically includes: Calculate the change direction of the phase and amplitude of the I-channel and Q-channel signals respectively; Dynamically adjust the value range of the compensation coefficient based on the amplitude difference , to achieve adaptive compensation in different channel environments.

2. The coding and decoding method for earthquake early warning encrypted transmission according to claim 1 is characterized in that: The encryption process specifically includes: Scramble the constellation points of the QAM modulated signal using a pseudo-random sequence; A reverse mapping mechanism based on a predefined mapping table is adopted to ensure the symmetry between the encrypted signal and the decrypted signal.

3. The coding and decoding method for earthquake early warning encrypted transmission according to claim 1 is characterized in that: The channel equalization processing specifically includes: A multi-stage equalizer is used to gradually adjust the received signal. The primary equalizer is used to filter out high-frequency noise, and the secondary equalizer is used to restore the signal amplitude.

4. The coding and decoding method for earthquake early warning encrypted transmission according to claim 1 is characterized in that: The compensation factor The range is [0.1,1.0], the compensation coefficient The range is [0.05, 0.8], and the specific value is dynamically adjusted according to the channel noise.

5. The coding and decoding method for earthquake early warning encrypted transmission according to claim 1 is characterized in that: The layout of the sensor array includes: For shallow earthquakes with focal depths less than 10 km, the sensor spacing should not exceed 2 km; For deep earthquakes, the sensor spacing is appropriately relaxed to 5 kilometers.

6. The coding and decoding method for earthquake early warning encrypted transmission according to claim 1 is characterized in that: Also includes: Output the seismic wave signal strength curve in real time through the receiving end display device; Automatically trigger the disaster prevention and mitigation control system to initiate emergency response.

7. The coding and decoding method for earthquake early warning encrypted transmission according to claim 2 is characterized in that: The transmission method of the encrypted signal includes: Wireless communication is achieved through Zigbee, LoRa or 5G technology; Wired communication is achieved through fiber optic networks.

8. The coding and decoding method for earthquake early warning encrypted transmission according to claim 2 is characterized in that: The reverse mapping mechanism includes: Matching the encrypted constellation points with the decrypted constellation points by table lookup; When the table lookup error exceeds the preset threshold, the resynchronization mechanism is automatically triggered.

9. The coding and decoding method for earthquake early warning encrypted transmission according to claim 1, characterized in that: The output forms of the earthquake early warning information include: Push real-time alerts via mobile devices; Generate a map of the affected area based on the epicenter location.

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