A malicious interference prevention FSK vehicle lock remote control method, system, device and storage medium

Abstract

The application provides a malicious interference prevention FSK vehicle lock remote control method, system, device and storage medium, and belongs to the technical field of communication. The method comprises the following steps: using a preset spread spectrum code sequence to perform direct sequence spread spectrum on an original remote control instruction at a signal sending end, and then transmitting the radio frequency signal after FSK modulation; the signal receiving end receives the radio frequency signal sent by the signal sending end and the same frequency interference signal generated by the lock vehicle jammer, performs FSK demodulation, and uses the same preset spread spectrum code sequence to perform despreading, suppresses the same frequency interference by using the orthogonality of the preset spread spectrum code sequence, and restores the original remote control instruction. The application also proposes an engineering optimization scheme for replacing the integrator with a low-pass filter for despreading. Simulation shows that when the interference signal strength is much greater than the normal signal, the system can still maintain a very low bit error rate. The physical layer solves the same frequency malicious interference problem of the vehicle lock remote control system, ensures accurate transmission of the instruction, eliminates the safety hazard of the false lock, and improves the safety of the vehicle.

Description

Technical Field

[0001] This invention belongs to the field of communication technology, and specifically relates to a method, system, device and storage medium for preventing malicious interference with FSK car lock remote control. Background Technology

[0002] Remote door locks are now standard equipment on most vehicles. Owners can remotely lock and unlock their cars by pressing a button on the remote key, greatly enhancing convenience. However, in practice, theft using car lock jammers is not uncommon. A car lock jammer is essentially a signal jammer; it lacks decoding or unlocking capabilities. Its working principle is to emit a strong signal at the same frequency as the car lock remote signal, thus overwriting or disrupting the remote control command. When the owner presses the lock button, the strong signal emitted by the jammer and the lock command signal from the remote key are simultaneously received by the vehicle's receiving system. Because the interference signal is much stronger than the normal remote signal, the vehicle's receiving system cannot accurately extract the valid remote control command from the strong interference, resulting in the doors not actually locking. At this point, the owner often hears a "click" sound or sees the turn signal flashing, mistakenly believing the doors are locked, and leaves. Criminals then open the car door and steal the car.

[0003] To address the aforementioned issues, existing encryption technologies, such as rolling codes, which use different passwords for each remote control command sent, can prevent signal interception and copying. However, they cannot solve the problem of signals being directly blocked or obstructed by strong interference signals during transmission. Using filters at the receiving end is currently the primary anti-interference method for electronic devices, effectively filtering out interference signals with frequencies different from the useful signal, but it is ineffective against interference at the same frequency. Therefore, improving the anti-interference capability of car lock remote control systems from the underlying communication link, ensuring that locking commands can still be reliably received and executed in complex electromagnetic environments, has become an urgent technical challenge. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method, system, device, and storage medium for preventing malicious interference with FSK vehicle lock remote control.

[0005] To achieve the above objectives, the present invention provides a method for preventing malicious interference with FSK vehicle lock remote control, comprising the following steps: The original remote control command signal generated by the remote control signal transmitter of the target vehicle lock is acquired; based on the original remote control command signal and the preset spreading code sequence, a spread spectrum remote control command signal is obtained; the spread spectrum remote control command signal is modulated into an FSK radio frequency signal by frequency shift keying (FSK) and transmitted.

[0006] If there is external co-frequency interference signal during the transmission process, the FSK radio frequency signal and the interference signal will be superimposed to form a radio frequency hybrid signal.

[0007] The radio frequency mixed signal is demodulated by FSK to obtain a baseband mixed signal. Based on the baseband mixed signal and the preset spreading code sequence, despreading is completed by integration or low-pass filtering to obtain the baseband signal. The baseband signal is compared and held to recover the original remote control command signal.

[0008] Preferably, the preset spreading code sequence is a Walsh code sequence, and the length of the Walsh code sequence is L=2ⁿ, where n is a positive integer and L is the length of the preset spreading code sequence.

[0009] Preferably, the step of modulating the spread spectrum remote control command signal into an FSK radio frequency signal and transmitting it via frequency shift keying (FSK) specifically includes: outputting a high-frequency carrier signal when the level of the spread spectrum remote control command signal is greater than 0; and outputting a low-frequency carrier signal when the level of the spread spectrum remote control command signal is less than or equal to 0.

[0010] Preferably, based on the baseband mixed signal and the preset spreading code sequence, and after despreading through integration or low-pass filtering to obtain the baseband signal, the original remote control command signal is recovered by level comparison and holding of the baseband signal. Specifically, this includes: obtaining a product signal based on the baseband mixed signal and the preset spreading code sequence; performing definite integration on the product signal using an integrator with the symbol period of the original remote control command signal as the time interval to obtain the baseband signal; or, filtering the product signal using a low-pass filter to obtain the baseband signal; and recovering the original remote control command signal by level comparison and holding of the baseband signal.

[0011] Preferably, the original remote control command signal is a 0 / 1 random digital signal with a rate of 2Kbps; before the original remote control command signal is multiplied by the preset spreading code sequence, it needs to undergo level conversion processing to convert the 0 / 1 digital signal into a +1 / -1 digital signal.

[0012] Preferably, the FSK radio frequency signal is transmitted to the signal receiving end of the vehicle lock remote control via a wireless transmission channel. If there is an external co-channel interference signal during the transmission process, the FSK radio frequency signal and the interference signal are superimposed to form a radio frequency hybrid signal. The wireless transmission channel includes a multipath Rayleigh fading channel and an additive white Gaussian noise channel.

[0013] Preferably, the co-channel interference signal is a constant-amplitude sinusoidal signal with the same frequency as the carrier frequency of the FSK radio frequency signal; based on the original remote control command signal and the preset spreading code sequence, a spread spectrum remote control command signal is obtained; specifically, the original remote control command signal is multiplied by the preset spreading code sequence to obtain the spread spectrum remote control command signal.

[0014] This invention also provides an anti-malicious interference FSK car lock remote control system, comprising: The signal generation and transmission module is used to acquire the original remote control command signal generated by the target vehicle lock remote control signal transmitter; based on the original remote control command signal and the preset spreading code sequence, a spread spectrum remote control command signal is obtained; the spread spectrum remote control command signal is modulated into an FSK radio frequency signal by frequency shift keying (FSK) and transmitted.

[0015] The signal transmission module is used to superimpose the FSK radio frequency signal and the interference signal to form a radio frequency hybrid signal if there is an external co-frequency interference signal during the transmission process.

[0016] The signal receiving and processing module is used to perform FSK demodulation on the radio frequency mixed signal to obtain a baseband mixed signal, and based on the baseband mixed signal and the preset spreading code sequence, perform despreading through integration or low-pass filtering to obtain a baseband signal, and perform level comparison and hold on the baseband signal to recover the original remote control command signal.

[0017] The present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement any of the steps in the anti-malicious interference FSK car lock remote control method.

[0018] The present invention also provides a computer-readable storage medium storing a computer program that, when loaded by a processor, can execute any of the steps in the anti-malicious interference FSK vehicle lock remote control method.

[0019] The present invention provides a method for preventing malicious interference with FSK car lock remote control, which has the following advantages: The present invention performs spread spectrum processing by multiplying the original remote control command with a preset spreading code sequence at the signal transmitting end, giving the signal a unique identification characteristic; the receiving end multiplies the demodulated baseband mixed signal with the same spreading code sequence and performs despreading through integration or low-communication filtering, thereby accurately recovering the original command from signals containing strong co-channel interference. Interference signals lacking this identification characteristic are automatically suppressed during the despreading process. This invention completely solves the co-channel interference problem that traditional filters and encryption technologies cannot handle at the physical layer. Simulation verification shows that even when the interference intensity is 16,000 times that of the useful signal, the bit error rate is still less than 0.0003; user operating habits do not need to be changed, it is compatible with existing FSK hardware architecture, and can be deployed at low cost through software or firmware upgrades; it fundamentally eliminates the security risk of "fake lock" theft caused by car lock jammers. Attached Figure Description

[0020] To more clearly illustrate the embodiments and design schemes of the present invention, the accompanying drawings required for this embodiment will be briefly described below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart illustrating a method for preventing malicious interference with FSK car lock remote control according to an embodiment of the present invention; Figure 2 This is a model of an anti-malicious interference FSK car lock remote control system using integrator despreading in an embodiment of the present invention; Figure 3 This is a model of an anti-malicious interference FSK car lock remote control system using filter despreading, as described in an embodiment of the present invention. Figure 4 This illustrates the relationship between the transmitted signal strength of the jammer and the bit error rate in an embodiment of the present invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0023] like Figure 2As shown, this invention provides an anti-malicious interference FSK car lock remote control system, specifically an anti-malicious interference FSK car lock remote control system based on spread spectrum technology. It includes three parts: a signal generation and transmission module, a signal transmission module, and a signal reception and processing module, corresponding to the car door lock remote key, the wireless signal propagation environment, and the door lock signal receiving and processing equipment on the vehicle, respectively. Specifically:

[0024] The signal generation and transmission module is used to acquire the original remote control command signal generated by the target vehicle lock remote control signal transmitter; based on the original remote control command signal and the preset spreading code sequence, a spread spectrum remote control command signal is obtained, and the spread spectrum remote control command signal is modulated into an FSK radio frequency signal through frequency shift keying (FSK) and transmitted.

[0025] The signal generation and transmission section handles command generation, spread spectrum, and FSK modulation. Remote control commands are 0 / 1 random digital signals, generated by the Bernoulli Binary Generator module at a rate of 2Kbps. These are converted to +1 / -1 digital signals by a level converter composed of Add, Constant, and Gain modules, and then sent to the Product module for multiplication with Walsh code to achieve spread spectrum. The Walsh code is generated by the Walsh Code Generator module and has a length of L=2. n (n is a positive integer), the rate is (2×L)Kbps, and the numbers are 0 to L-1. The spread spectrum signal is sent to the control terminal of the Switch module, and the high-frequency and low-frequency sine signals are respectively connected to the upper and lower input terminals of the Switch module to realize frequency shift keying (FSK) modulation. When the control terminal level is greater than 0, the output terminal of the Switch module is connected to the high-frequency sine signal of its upper input terminal; when the control terminal level is less than or equal to 0, the output terminal of the Switch module is connected to the low-frequency sine signal of its lower input terminal. The sine signals are generated by the Sine Wave module, with an amplitude of 1, frequencies of 1500KHz and 1000KHz respectively, and an initial phase of 0.

[0026] The signal transmission module is used to superimpose the FSK radio frequency signal and the interference signal to form a radio frequency hybrid signal if there is an external co-frequency interference signal during the transmission process.

[0027] The wireless transmission channel in the model consists of a Multipath Rayleigh Fading Channel module and an AWGNChannel module. The Multipath Rayleigh Fading Channel module simulates the multipath effect of wireless signals during propagation, while the AWGNChannel module simulates background noise in the wireless environment. Before being sent into the transmission channel, the modulated FSK signal is injected with a co-channel interference signal via the Sum module, simulating a car lock jammer. The co-channel interference signal is a constant-amplitude sine wave signal generated by the Sine Wave module, with a frequency of 1500kHz or 1000kHz and an initial phase of 0.

[0028] The signal receiving and processing module is used to perform FSK demodulation on the radio frequency mixed signal to obtain a baseband mixed signal, and based on the baseband mixed signal and the preset spreading code sequence, perform despreading through integration or low-pass filtering to obtain a baseband signal, and perform level comparison and hold on the baseband signal to recover the original remote control command signal.

[0029] The signal receiving and processing section performs FSK demodulation, despreading, level comparison, and bit error rate detection. After passing through the wireless transmission channel, the modulated FSK signal is separated into two signals by a bandpass filter, one for high-frequency components and one for low-frequency components. The high-frequency and low-frequency signals then enter the Abs module (and its subsequent integrator) for non-coherent demodulation. FSK demodulation can be divided into coherent and non-coherent demodulation. Although coherent demodulation is superior to non-coherent demodulation in terms of anti-interference capability, it is not commonly used in practical vehicle lock remote control systems due to its complex implementation and high cost. The output signal of the Abs module is sent to the Product module and multiplied with the Walsh code, then despread by the integrator. The integrator consists of an Integrator module, a Pulse Generator module, a Product module, and a Gain module, repeatedly calculating the definite integral value with a period of 0.5ms (corresponding to a command rate of 2Kbps). The two despread signals are then compared and held by the Relational Operator module and the Zero-Order Hold module to recover the command signal. The Zero-Order Hold module has a level holding time of 0.5ms (corresponding to a command rate of 2Kbps). The recovered command is sent to the Error Rate Calculation module for comparison with the original command from the transmitting end, and the bit error rate is calculated and displayed in the Display module. Simultaneously, the command recovered from the receiving end and the delayed command from the transmitting end are sent together to the Scope module for waveform comparison.

[0030] Analysis of the principle of the anti-malicious interference FSK car lock remote control system. The suppression effect of the anti-malicious interference FSK car lock remote control system based on spread spectrum technology on the signal of the car lock jammer stems from the orthogonality of the Walsh codes used in the spreading and despreading process. Walsh codes can be generated by the Hadamard matrix and are a set of orthogonal binary sequences (each bit is +1 or -1). Orthogonality means that for any two Walsh codes of the same length, when they are perfectly aligned in time (i.e., synchronized), the sum of the bitwise multiplications of one code sequence with the other code sequence is 0; the sum of the bitwise multiplications of any code sequence with itself is 1. The mathematical expression of the orthogonality of Walsh codes is as follows:

[0031] ; In the formula, T d W represents the symbol period of the remote control command (T represents the period, d represents the command data). i W j These are two code sequences in a Walsh code group (W represents the Walsh code, and i and j are the Walsh code's numbers in its code group). When the length of the Walsh code is L and the symbol period is Tw (T represents the period, w represents the Walsh code), T... d =L×Tw, where i and j take values ​​from 0 to L-1.

[0032] Let the binary instruction sequence generated by the car lock remote key be D (each bit is 1 or 0), and its code period be T. d Use Walsh code W i (The value of i ranges from 1 to L-1) The signal after spreading the command is DW i .

[0033] If the FSK high-frequency carrier frequency is f H The low-frequency carrier frequency is f L Where f represents frequency, H represents high frequency, and L represents low frequency, the modulated signal is: ; Assuming the interference signal has the same frequency as the low-frequency carrier, and since the first code sequence W0 in the Walsh code group is a DC signal of magnitude +1, the constant-amplitude sinusoidal signal generated by the car lock jammer... Equivalent to Where N is the amplitude of the interference signal. The signal that finally enters the wireless transmission channel is: ;

[0034] The vehicle-mounted system uses a bandpass filter to split the signal from the transmission channel into high-frequency and low-frequency paths, which are then demodulated separately. The resulting baseband signal after demodulation is... (High-frequency branch) and (Low-frequency branch). The two baseband signals are respectively coupled with Walsh code W... i Multiply and in instruction symbol period T d Integrating over a time period, the despreading process for the high-frequency and low-frequency branches is as follows:

[0035] ; ; After despreading, the Relational Operator module is used to compare the levels of the high and low frequency signals. (Right now When ), the Relational Operator module outputs 1; when (Right now When ), the Relational Operator module outputs 0. Logically speaking, the signal output by the RelationalOperator module is the instruction sequence D.

[0036] As can be seen from the above, by spreading the spectrum at the transmitting end and despreading it at the receiving end, the complete orthogonality of Walsh codes can be used to effectively suppress co-channel interference and completely avoid the safety hazards caused by car lock jammers.

[0037] Performance analysis of the FSK car lock remote control system to prevent malicious interference. The transmission channel E... b With / N0 set to 20dB, a 5-second (10000-bit) simulation test was performed on the anti-malicious interference FSK car lock remote control system model. The relationship between interference signal strength and bit error rate (BER) is as follows: Figure 4 As shown. The interference signal strength is represented by the amplitude A of the signal transmitted by the car lock jammer. i (A represents amplitude, i represents interference) and the amplitude A of the signal transmitted by the car lock remote key. k The ratio A (where A represents amplitude and k represents the remote control key) i / A k In other words, without spread spectrum (traditional FSK car lock remote control system), A i / A k When the value is 1, the bit error rate (BER) is approximately 0.2%, and the command cannot be transmitted accurately. The command is spread-spectrum transmitted using Walsh codes of lengths 16, 32, and 64 (to prevent malicious interference with the FSK car lock remote control system), and the BER is plotted as a function of A. i / A k The changing curves show that the Walsh code lengths are 16, 32, and 64, and A... i / A kWhen the values ​​are less than 500, 20000, and 16000 respectively, the bit error rate is below 3e-4. Simulation results show that the spread spectrum-based anti-malicious interference FSK car lock remote control system effectively suppresses co-channel interference signals generated by the car lock jammer, ensuring accurate transmission of commands at the physical layer.

[0038] Simulation test of the FSK car lock remote control system to prevent malicious interference. The car lock remote control system model is a theoretical simulation of the actual car lock remote control signal processing process. The simulation is carried out by setting the parameter values ​​of the main modules in the model according to the technical specifications of the actual equipment and the usage scenario, involving three aspects: signal generation and transmission, wireless transmission channel, and signal reception and processing.

[0039] Simulation of signal generation and transmission. The car lock remote key is used to send short command signals (such as unlocking, locking, activating the alarm, etc.), requiring low data rate and prioritizing low power consumption and signal stability. Data transmission rates are typically 2Kbps to 20Kbps, with some systems reaching 100Kbps. Therefore, the parameter Samples per frame of the Bernoulli Binary Generator module in the model is set to (e... -3 ) / 2, generates a random digital signal with a rate of 2Kbps, simulating binary commands for remote control of car locks.

[0040] If a Walsh code of length L is used to spread a command signal with a rate of 2Kbps, the resulting digital baseband signal rate is (2×L)Kbps. For example, when L is 32, the digital baseband signal rate is 64Kbps. FSK modulation requires two carriers, one high-frequency and one low-frequency. The frequency of the carrier signal is usually much higher than the frequency of the baseband signal (more than 10 times), and the frequency difference between the two carriers should be greater than twice the frequency of the baseband signal to ensure that the modulated signal can be effectively transmitted and the original baseband signal can be recovered after demodulation. Therefore, the frequency (rad / sec) parameter of the two Sine Wave modules in the model is set to (1500e3)*2*pi and (1000e3)*2*pi, respectively, to generate 1500KHz and 1000KHz sine signals as carriers.

[0041] Simulation of Wireless Transmission Channels. In daily life, cars are generally parked in underground or open-air parking lots. The impact of these two types of parking lots on the transmission of short-range wireless signals (such as car lock remote control signals) differs significantly. Underground parking lots are enclosed spaces with a dense distribution of metal vehicles, ventilation ducts, roller shutters, and other metal objects, resulting in multipath interference, reflection, and scattering of signals. This places higher demands on the system's accurate signal transmission and can serve as a typical scenario for simulating an FSK car lock remote control system designed to prevent malicious interference.

[0042] In underground environments, multipath delays are typically tens to hundreds of nanoseconds (ns) due to the influence of site structure, materials, and signal frequency, and the intensity difference between signals from different paths usually does not exceed 3 dB. Therefore, the parameters Discrete path delay vector (s) of the Multipath Rayleigh FadingChannel module in the model are set to [0, 1e-7, 2e-7]; and Average path gain vector (dB) is set to [0, -3, -6] to simulate the multipath effect of wireless signal transmission in an underground parking lot.

[0043] Typically, when a car owner uses a remote control while leaving their vehicle, there is relative motion between the person and the vehicle. This generates a Doppler frequency shift, which is the frequency change caused by the relative motion between the transmitter and receiver. The formula for calculating the Doppler frequency shift Δf of radio waves is:

[0044] In the formula, f0 is the frequency of the transmitted signal carrier (the model has two carrier frequencies, 1500 kHz and 1000 kHz; the higher the signal frequency, the greater the Doppler shift, so f0 is taken as 1500 kHz), v is the relative speed (1.5 m / s for walking), θ is the angle between the direction of movement and the direction of signal propagation (cosθ = 1 when the transmitter and receiver are facing each other), and C is the speed of light (approximately 3 × 10⁸ m / s). Substituting these values ​​into the formula, we can calculate that the Doppler shift Δf generated by the car lock remote control system under walking conditions is 0.015 Hz. Therefore, the parameter Maximum Doppler shift (Hz) of the Multipath Rayleigh Fading Channel module in the model is set to 0.015.

[0045] The signal-to-noise ratio (SNR) of short-range wireless remote control signals propagating in underground parking lots is typically low, generally between 10dB and 20dB. This can be improved by configuring the E in the AWGN Channel module. b / N0(dB) is used to simulate the background noise of the environment. SNR and E b / N0 are two key performance indicators in digital communication systems, both used to measure signal quality, but with different definitions and application scenarios. SNR is the ratio of signal power S to noise power N, reflecting the ratio of signal to noise intensity across the entire bandwidth; E b / N0 represents the energy per bit, E b The ratio of Eb / N0 (where E represents energy and b represents bits) to the noise power spectral density N0 is the normalized signal-to-noise ratio (SNR), which eliminates the influence of system bandwidth and transmission rate. The conversion formula between SNR and Eb / N0 is:

[0046] In the formula, R b (R represents rate, b represents bit) is the information transmission rate (bit rate), and W is the system bandwidth. The bandwidth of a two-level digital signal usually does not refer to the frequency of the signal itself, but rather to the spectral range occupied by its transmission rate. According to the Nyquist criterion, the minimum theoretical bandwidth required for intersymbol interference-free transmission is half the signal baud rate (which is the bit rate for a two-level digital signal). In the model, the transmission rate of the command signal is 2Kbps, and after being spread by a Walsh code of length L, the generation rate is R. b A two-level digital signal with bandwidth of (2×L) Kbps requires a minimum Nyquist bandwidth of R. b / 2=(2×L)Kbps / 2=(1×L)KHz. Since the FSK modulation of the baseband signal on the carrier can be considered as the addition of the baseband signal and its logical NOT signal modulated separately on the high and low carriers using ASK modulation, and the bandwidth of the ASK signal is twice the bandwidth of the baseband signal, the bandwidth of the FSK signal is four times the bandwidth of the baseband signal, i.e., W=(4×L)KHz. Let R... b Substituting W into the previous formula, we get SNR(dB) = Eb / N0(dB) - 3(dB). Therefore, the parameter E of the AWGN Channel module in the model... b / N0(dB) is set to 20 (equivalent to SNR=17dB) to simulate the background noise of short-range wireless signal propagation in an underground parking lot.

[0047] Simulation of signal reception and processing. At the receiver, the FSK signal is split into high-frequency and low-frequency signals by a bandpass filter. When the command signal rate is 2Kbps and the length of the Walsh code used for spreading is L, the center frequency of the high-frequency branch bandpass filter is 1500KHz and the bandwidth is (2×L)KHz; the center frequency of the low-frequency branch bandpass filter is 1000KHz and the bandwidth is (2×L)KHz.

[0048] For example, when L=16, the parameter Lower passbandedge frequency (rad / s) of the Analog Filter Design module in the high-frequency branch is set to (1468e3)*2*pi, and the parameter Upper passband edge frequency (rad / s) is set to (1532e3)*2*pi.

[0049] In the low-frequency branch, the parameter Lower passband edge frequency (rad / s) of the Analog Filter Design module is set to (968e3)*2*pi, and the parameter Upper passband edge frequency (rad / s) is set to (1032e3)*2*pi.

[0050] The high-frequency and low-frequency signals are despread through integration, and the period of integration repetition is controlled by a pulse signal. For example... Figure 3 As shown, since the command signal rate is 2Kbps (symbol period is 0.5ms), the Period (secs) parameter of the PulseGenerator module in the model is set to (1e-3) / 2, meaning a definite integral is performed once within each command symbol period. Then, the integral result is divided by the command symbol period (the Gain parameter of the Gain module in the model is set to 2000), and the command signal can be recovered through level comparison and hold. The Relational Operator module in the model has its Relational operator parameter set to >= and its Threshold parameter set to 0. The Zero-Order Hold module has its Sample time (-1 for inherited) parameter set to (1e-3) / 2.

[0051] The anti-malicious interference FSK car lock remote control system uses an integrator for despreading, which can more accurately recover the original signal and improve the signal-to-noise ratio compared to using a low-pass filter. However, integrators have problems such as high synchronization requirements, complex hardware implementation, and poor dynamic adaptability, and are not widely used in engineering practice. In FSK modulation car lock remote control systems, using a low-pass filter in combination with a limiter and a multiplier can achieve sufficient processing gain and anti-interference capability, resulting in a high cost-performance ratio. Therefore, the anti-malicious interference FSK car lock remote control system model is optimized by replacing the integrator with an Analog FilterDesign module (analog low-pass filter) and a Saturation module (limiter). Since the command signal rate is 2Kbps, the parameter Passband edge frequency (rad / s) of the Analog FilterDesign module is set to (2e3)*2*pi; the parameter Upper limit of the Saturation module is set to +1, and the parameter Lower limit is set to -1.

[0052] The FSK car lock remote control system based on spread spectrum technology addresses the FSK modulation method used in mid-to-high-end car remote controls by incorporating spread spectrum and despreading processes. This physically solves the problem of remote control signal interference, effectively countering malicious attacks from car lock jammers and protecting the safety of car owners' property. As an important aspect of automotive safety technology, it will undoubtedly see widespread application in the future, driven by a combination of policy, technological advancements, and market demand.

[0053] Based on this, the present invention provides a method for preventing malicious interference with FSK car lock remote control, specifically as follows: Figure 1 As shown, it includes the following steps: S1. Signal Transmitter Processing Steps S101, Obtain the original remote control command signal.

[0054] Specifically, the original remote control command signal generated by the remote control signal transmitter of the target vehicle lock is acquired. The original remote control command signal is a 0 / 1 random digital signal with a rate of 2Kbps. Preferably, before being multiplied with other modules, it undergoes level conversion processing, converting the 0 / 1 digital signal into a +1 / -1 digital signal.

[0055] S102. Spread spectrum processing is performed on the original remote control command signal.

[0056] Based on the original remote control command signal and the preset spreading code sequence, a spread spectrum remote control command signal is obtained. The preset spreading code sequence is a Walsh code sequence with a length L = 2ⁿ, where n is a positive integer and L is the length of the preset spreading code sequence. The Walsh code can be generated by a Hadamard matrix and is a set of orthogonal binary sequences, with each bit taking the value of +1 or -1.

[0057] S103. Modulate the spread spectrum signal using FSK and transmit it.

[0058] The spread spectrum remote control command signal is modulated into an FSK radio frequency signal and transmitted using Frequency Shift Keying (FSK). Specifically, this includes: outputting a high-frequency carrier signal when the level of the spread spectrum remote control command signal is greater than 0; and outputting a low-frequency carrier signal when the level of the spread spectrum remote control command signal is less than or equal to 0. In one specific embodiment, the high-frequency carrier frequency is 1500 kHz, and the low-frequency carrier frequency is 1000 kHz.

[0059] S2, Wireless Transmission Steps The FSK radio frequency signal is transmitted wirelessly to the signal receiver of the car lock remote control. If there is external co-channel interference during transmission, the FSK radio frequency signal and the interference signal are superimposed to form a mixed radio frequency signal. Specifically, the wireless transmission channel includes a multipath Rayleigh fading channel and an additive white Gaussian noise channel. The co-channel interference signal is a constant-amplitude sine wave with the same frequency as the carrier frequency of the FSK radio frequency signal, used to simulate malicious interference generated by a car lock jammer.

[0060] In one specific embodiment, taking an underground parking lot as a typical application scenario, the multipath delay is set to 0, 1e−7, 2e−7 seconds, the signal strength difference between each path does not exceed 3dB, the Doppler frequency shift is 0.015Hz, and the corresponding channel signal-to-noise ratio is Eb / N0=20dB.

[0061] S3, Signal Receiver Processing Steps S301, Perform FSK demodulation on the received signal. A bandpass filter is used to separate the high-frequency and low-frequency components into two signals, which are then fed into the Abs module to complete incoherent demodulation.

[0062] S302. Perform despreading processing on the demodulated signal. Based on the baseband mixed signal and the preset spreading code sequence, a product signal is obtained; the product signal is then integrated by an integrator with the symbol period of the original remote control command signal as the time interval to obtain the baseband signal; or, the product signal is filtered by a low-pass filter to obtain the baseband signal.

[0063] In one specific embodiment, the symbol period of the original remote control command signal is 0.5ms (corresponding to a command rate of 2Kbps), and the integrator repeatedly calculates the definite integral value with a period of 0.5ms.

[0064] S303. Level Comparison and Hold, Recovering the Original Command: The baseband signal is compared and held to recover the original remote control command signal. Specifically, the Relational Operator module is used to compare the levels of the high-frequency and low-frequency signals: when the high-frequency branch signal is greater than or equal to the low-frequency branch signal, 1 is output; when the high-frequency branch signal is less than the low-frequency branch signal, 0 is output. The Zero-Order Hold module is used to hold the level with a period of 0.5ms to recover the original command signal.

[0065] Existing filters and encryption technologies are ineffective against strong co-channel signals emitted by car lock jammers. This invention utilizes spread spectrum technology and the orthogonality of the spreading code sequence to automatically suppress co-channel interference signals during despreading, fundamentally solving the long-standing problem of malicious co-channel interference in car lock remote control systems at the physical layer and completely eliminating the security risk of "fake lock" theft. Simulation tests show that even when the interference signal strength reaches 16,000 times that of the useful signal, the system's bit error rate remains below 0.0003, ensuring accurate transmission of remote control commands in harsh electromagnetic environments without requiring users to change their operating habits. This invention is based on the mature FSK modulation method, requiring no changes to the RF front-end hardware architecture. Spread spectrum and despreading processing are mainly implemented through digital baseband algorithms, allowing for deployment via software or firmware upgrades. With minimal hardware modifications and low cost, it possesses promising prospects for industrial applications.

[0066] This invention also provides a computer device. At the hardware level, the computer device includes a processor, an internal bus, a network interface, memory, and non-volatile memory, and may also include other hardware required for business operations. The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it to implement the aforementioned anti-malicious interference FSK car lock remote control method.

[0067] The present invention also provides a computer-readable storage medium storing a computer program that can be used to execute the above-described anti-malicious interference FSK car lock remote control method.

[0068] Specific limitations regarding the computational system for the anti-malicious interference FSK car lock remote control method can be found in the limitations described above, and will not be repeated here. Each module in the aforementioned anti-malicious interference FSK car lock remote control system can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in the computer device, or stored in the computer device's memory as software, so that the processor can call and execute the corresponding operations of each module.

[0069] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. Furthermore, the above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preventing malicious interference with FSK car lock remote control, characterized in that, Includes the following steps: The original remote control command signal generated by the remote control signal transmitter of the target vehicle lock is acquired; based on the original remote control command signal and the preset spreading code sequence, a spread spectrum remote control command signal is obtained; the spread spectrum remote control command signal is modulated into an FSK radio frequency signal by frequency shift keying (FSK) and transmitted. If there is external co-channel interference signal during transmission, the FSK radio frequency signal and the interference signal will be superimposed to form a mixed radio frequency signal; The radio frequency mixed signal is demodulated by FSK to obtain a baseband mixed signal. Based on the baseband mixed signal and the preset spreading code sequence, despreading is completed by integration or low-pass filtering to obtain the baseband signal. The baseband signal is compared and held to recover the original remote control command signal.

2. The method for preventing malicious interference with FSK car lock remote control according to claim 1, characterized in that, The preset spreading code sequence is a Walsh code sequence, and the length of the Walsh code sequence is L=2ⁿ, where n is a positive integer and L is the length of the preset spreading code sequence.

3. The method for preventing malicious interference with FSK car lock remote control according to claim 1, characterized in that, The step of modulating the spread spectrum remote control command signal into an FSK radio frequency signal and transmitting it via Frequency Shift Keying (FSK) specifically includes: outputting a high-frequency carrier signal when the level of the spread spectrum remote control command signal is greater than 0; and outputting a low-frequency carrier signal when the level of the spread spectrum remote control command signal is less than or equal to 0.

4. The method for preventing malicious interference with FSK car lock remote control according to claim 1, characterized in that, Based on the baseband mixed signal and the preset spreading code sequence, and after despreading through integration or low-pass filtering to obtain the baseband signal, the original remote control command signal is recovered by comparing and holding the level of the baseband signal. Specifically, this includes: multiplying the baseband mixed signal with the preset spreading code sequence to obtain a product signal; performing definite integration on the product signal using an integrator with the symbol period of the original remote control command signal as the time interval to obtain the baseband signal; or filtering the product signal using a low-pass filter to obtain the baseband signal; and comparing and holding the level of the baseband signal to recover the original remote control command signal.

5. The method for preventing malicious interference with FSK car lock remote control according to claim 1, characterized in that, The original remote control command signal is a 0 / 1 random digital signal with a rate of 2Kbps. Before the original remote control command signal is multiplied by the preset spreading code sequence, it needs to undergo level conversion processing to convert the 0 / 1 digital signal into a +1 / -1 digital signal.

6. The method for preventing malicious interference with FSK car lock remote control according to claim 1, characterized in that, The FSK radio frequency signal is transmitted to the signal receiving end of the vehicle lock remote control via a wireless transmission channel. If there is an external co-channel interference signal during the transmission process, the FSK radio frequency signal and the interference signal are superimposed to form a radio frequency mixed signal. The wireless transmission channel includes a multipath Rayleigh fading channel and an additive white Gaussian noise channel.

7. The method for preventing malicious interference with FSK car lock remote control according to claim 1, characterized in that, The co-channel interference signal is a constant-amplitude sinusoidal signal with the same frequency as the carrier frequency of the FSK radio frequency signal; based on the original remote control command signal and the preset spreading code sequence, a spread spectrum remote control command signal is obtained; specifically, the original remote control command signal is multiplied by the preset spreading code sequence to obtain the spread spectrum remote control command signal.

8. A remote control system for preventing malicious interference with FSK car locks, characterized in that, include: The signal generation and transmission module is used to acquire the original remote control command signal generated by the target vehicle lock remote control signal transmitter. Based on the original remote control command signal and the preset spreading code sequence, a spread spectrum remote control command signal is obtained. The spread spectrum remote control command signal is modulated into an FSK radio frequency signal by frequency shift keying (FSK) and then transmitted. The signal transmission module is used to superimpose the FSK radio frequency signal and the interference signal to form a radio frequency hybrid signal if there is an external co-channel interference signal during the transmission process. The signal receiving and processing module is used to perform FSK demodulation on the radio frequency mixed signal to obtain a baseband mixed signal, and based on the baseband mixed signal and the preset spreading code sequence, perform despreading through integration or low-pass filtering to obtain a baseband signal, and perform level comparison and hold on the baseband signal to recover the original remote control command signal.

9. A computer device, comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is loaded by the processor, it is able to perform the steps of the method according to any one of claims 1 to 7.

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