Rail transit wireless anti-interference communication method and system

Abstract

The application discloses a kind of rail transit wireless anti-interference communication method and system, it is related to signal anti-interference technical field, including, extraction train real-time speed and calculate instantaneous acceleration, acceleration algebra is mapped into fractional order rotation angle, control fractional order Fourier transformer is rotated to received signal tensor, realize the decoupling and energy concentration of Doppler diffusion signal;Adaptive nonlinear metric space is constructed using local correlation entropy in fractional order subspace, truncate non-gaussian impact transient energy, output pure phase sequence;Pure phase sequence is mapped into generalized coordinate and momentum of Hamiltonian phase space, implicit midpoint symplectic integration is iterated evolution, realize signal trajectory self-healing and steady-state recovery;Combined with energy monitoring and MAC layer cross-layer collaborative mechanism, realize physical layer and link layer closed-loop protection.It is applicable to high-speed rail communication, can effectively enhance signal anti-interference ability, improve communication reliability under low signal-to-noise ratio environment.

Description

Technical Field

[0001] This invention relates to the field of signal anti-interference technology, and in particular to a wireless anti-interference communication method and system for rail transit. Background Technology

[0002] In high-speed operation, rail transit communication systems are susceptible to interference from non-Gaussian impulses, such as time-varying Doppler shifts caused by train movement and sudden arc pulses from the overhead contact line. These interferences lead to frequency spread, amplitude fluctuations, and phase drift in the received signal, making it difficult for traditional demodulation methods based on phase-locked loops and fixed filters to accurately recover the signal, severely impacting the reliability and security of communication.

[0003] Existing anti-interference technologies mainly rely on external triggers to detect pulses or use highly redundant coding, but they still suffer from misjudgment, delay, or data loss in environments with extremely low signal-to-noise ratios and rapid changes.

[0004] Furthermore, traditional signal processing methods typically map time-domain signals directly to the frequency domain, failing to effectively decouple Doppler spread energy and lacking adaptive processing capabilities for transient impacts. Therefore, rail transit communication still faces technical bottlenecks such as insufficient reliability, difficulty in data recovery, and low system robustness in complex scenarios involving high speed, multiple interferences, and low signal-to-noise ratios. Summary of the Invention

[0005] In view of the aforementioned existing problems, the present invention is proposed.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a wireless anti-interference communication method for rail transit, comprising,

[0008] After extracting the real-time macroscopic kinematic parameters of the train, the macroscopic kinematic parameters are algebraically mapped into the dynamic rotation degree of the fractional-order space: the received baseband signal tensor is spatially rotated using the dynamic rotation degree, the broadband signal diverged by the time-varying Doppler frequency shift is decoupled and forcibly aggregated in a specific fractional-order subspace, and the energy-concentrated fractional-order feature stream is output.

[0009] For non-Gaussian impact disturbances, a nonlinear metric space based on maximizing local correlation entropy is constructed within the fractional subspace; the fractional feature stream is input into the nonlinear metric space, and the impact transient energy is adaptively truncated in algebraic iterations using the extreme decay characteristics of the kernel function to output a clean phase sequence.

[0010] The phase characteristics of the pure phase sequence are mapped to regular conjugate variables in Hamiltonian phase space, and the communication correction is reconstructed into a dynamic evolution process. The symplectic integral operator with volume-preserving mapping is used to perform evolutionary solution on the variables. Under the premise of ensuring the absolute conservation of the intrinsic energy of the signal, the deviated trajectory is restored to the steady-state orbit, and the signal demodulation is completed.

[0011] As a preferred embodiment of the wireless anti-interference communication method for rail transit described in this invention, the macroscopic kinematic parameters include: acquiring instantaneous speed in real time through a bus interface with the train automatic control system, and calculating the instantaneous acceleration of the train along the track based on the instantaneous speed.

[0012] As a preferred embodiment of the wireless anti-interference communication method for rail transit described in this invention, the algebraic mapping includes mapping the train acceleration to a Doppler frequency using the constant speed of light, and amplifying the frequency change into a signal frequency change using the carrier center frequency; and mapping the frequency change to a fractional rotation degree using the inverse cotangent relation.

[0013] The received time-domain signal with Doppler interference acquired by the radio frequency front end is used as the baseband signal. After being input into the fractional Fourier transform, the orthogonal kernel function corresponding to the rotation degree is called to perform integration operation, and the received time-domain signal is mapped to the fractional domain signal.

[0014] By rotating the coordinate system within the fractional-order subspace along the rotation angle, the signal energy is projected onto a space orthogonal to the diffusion slope, generating a fractional-order characteristic flow in the form of a narrowband impulse peak, thereby achieving structural decoupling and energy concentration of the time-varying Doppler signal.

[0015] As a preferred embodiment of the wireless anti-interference communication method for rail transit described in this invention, the nonlinear metric space includes: constructing an adaptive transverse filter structure inside the processor of the baseband signal, and defining a local correlation entropy objective function to measure the deviation between the filter output and the desired signal in each local time window, so as to guide the dynamic weight update of each local time window in the filter output.

[0016] Within each clock cycle, the transient residual of the current local time window is calculated in real time, and dynamic weights are formed by exponential decay based on the transient residuals. These weights are used to adjust the filter tap weights so that the weights corresponding to sampling points with larger residuals are automatically reduced.

[0017] The adaptive truncation includes, when a sudden arc pulse occurs in the contact network, causing the transient residual to reach an extreme value, attenuating the dynamic weight to a value of zero, thereby automatically eliminating the local time window of non-Gaussian impact energy without the need for an external high-level trigger for pulse detection; and outputting the pure phase sequence stripped of non-Gaussian impact energy.

[0018] As a preferred embodiment of the wireless anti-interference communication method for rail transit described in this invention, the step of reconstructing communication correction into a dynamic evolution process includes: establishing two independent register spaces in the receiver; storing and defining the instantaneous phase extracted from the pure phase sequence as generalized coordinates, and storing and defining its instantaneous angular frequency as generalized momentum;

[0019] Construct the Hamiltonian function to characterize the total energy of a communication synchronization system: defined as the algebraic sum of the system's kinetic and potential energy terms;

[0020] Among them, the system kinetic energy term is characterized as a generalized momentum quadratic form weighted by the inverse of the equivalent inertia matrix, which is used to quantify the frequency offset drift rate; the system potential energy term is characterized as a nonlinear function determined by the phase-locked loop phase detection constraint characteristics.

[0021] As a preferred embodiment of the wireless anti-interference communication method for rail transit described in this invention, the step of using the volume-preserving symplectic integral operator to perform the solution includes: in the loop routine for performing carrier phase recovery, calling the symplectic integral solution module based on the implicit midpoint rule for iterative evolution;

[0022] The phase and angular frequency states of the current clock cycle are read, and the state quantities of the next clock cycle are cross-derived and updated by calculating the partial derivatives of the Hamiltonian function with respect to generalized momentum and generalized coordinates at the precise midpoint between the current state and the next unknown state.

[0023] The execution constraint is: to maintain the determinant of the state transition Jacobian matrix at 1 in algebra, to ensure that the phase space fluid is volume-preservingly mapped, so that the effective information energy volume of the signal will not be dissipated due to the truncation error of numerical integration during the process of the phase sequence being pulled back to the steady-state reference point by point.

[0024] As a preferred embodiment of the wireless anti-interference communication method for rail transit described in this invention, in the process of solving the symplectic integral, an energy monitoring process is established to calculate in real time the absolute deviation between the actual observed total Hamiltonian energy and the preset interference-free ideal total energy in the register, which is used as the Hamiltonian energy residual.

[0025] The Hamiltonian energy residual is sent to the medium access control layer processor as a confidence metric flag of the physical layer.

[0026] When the value of the flag bit exceeds the preset security tolerance threshold, the interrupt service routine is executed immediately, and redundant check bits of the forward error correction code are adaptively increased to achieve cross-layer closed-loop collaboration.

[0027] Secondly, the present invention provides a wireless anti-interference communication system for rail transit, including a data acquisition unit that extracts real-time macroscopic kinematic parameters of the train and algebraically maps the macroscopic kinematic parameters into a dynamic rotation degree of a fractional space. The received baseband signal tensor is spatially rotated using the dynamic rotation degree, and the broadband signal diverged by the time-varying Doppler frequency shift is decoupled and forcibly aggregated in a specific fractional subspace, outputting a fractional characteristic flow with concentrated energy.

[0028] The adjustment unit, for non-Gaussian impact disturbance, constructs a nonlinear metric space based on maximizing local correlation entropy within the fractional subspace; inputs the fractional feature stream into the nonlinear metric space, and utilizes the extreme decay characteristics of the kernel function to adaptively truncate the impact transient energy in algebraic iteration, outputting a pure phase sequence;

[0029] The output unit maps the phase characteristics of the pure phase sequence to regular conjugate variables in Hamiltonian phase space, reconstructing the communication correction into a dynamic evolution process; it uses a volume-preserving symplectic integral operator to perform evolutionary solutions on the variables, restoring the deviated trajectory to a steady-state orbit while ensuring the absolute conservation of the signal's intrinsic energy, thus completing signal demodulation.

[0030] Thirdly, the present invention provides a computer device including a memory and a processor, wherein the memory stores a computer program, wherein when the computer program is executed by the processor, it implements any step of the rail transit wireless anti-interference communication method as described in the first aspect of the present invention.

[0031] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, it implements any step of the rail transit wireless anti-interference communication method as described in the first aspect of the present invention.

[0032] The beneficial effects of this invention are as follows: it significantly improves the signal stability and reliability of rail transit wireless communication systems in high-speed train operating environments. By using fractional-order rotation and subspace decoupling, it eliminates signal energy dispersion caused by Doppler diffusion, achieving energy concentration and enhancing signal detectability under low signal-to-noise ratio conditions. Employing local correlation entropy adaptive truncation technology effectively eliminates sudden non-Gaussian impulse interference, reducing the impact of transient anomalies on signal demodulation and ensuring a pure and stable output phase sequence. Combining Hamiltonian dynamics self-healing and symplectic integral evolution, the signal can automatically recover to a steady state after deviating from its trajectory, improving the robustness of continuous communication. A cross-layer collaborative mechanism establishes a closed-loop feedback between the physical layer and the MAC layer. When the physical layer's repair capability reaches its limit, it can adaptively enhance forward error correction coding, further ensuring link reliability and anti-interference performance. The overall effect is a significant improvement in demodulation accuracy, signal stability, and link continuity of the communication system in high-speed, multi-interference environments. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, 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.

[0034] Figure 1 This is a flowchart of a wireless anti-interference communication method for rail transit.

[0035] Figure 2 This is a diagram of computer equipment used in a wireless anti-interference communication method for rail transit. Detailed Implementation

[0036] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0037] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0038] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0039] Reference Figure 1 and Figure 2 As one embodiment of the present invention, this embodiment provides a wireless anti-interference communication method for rail transit, comprising the following steps:

[0040] S1: After extracting the real-time macroscopic kinematic parameters of the train, the macroscopic kinematic parameters are algebraically mapped into the dynamic rotation degree of the fractional-order space. The received baseband signal tensor is spatially rotated using the dynamic rotation degree, and the broadband signal diverged by the time-varying Doppler frequency shift is decoupled and forcibly aggregated in a specific fractional-order subspace, outputting a fractional-order feature flow with concentrated energy.

[0041] Furthermore, the macroscopic kinematic parameters include instantaneous velocity acquired in real time through a bus interface with the train automatic control system, and instantaneous acceleration of the train along the track calculated based on the instantaneous velocity.

[0042] It should be noted that the instantaneous velocity is used to represent the relative motion state between the transmitting and receiving ends and to determine the amplitude of the Doppler frequency shift, while the instantaneous acceleration is used to characterize the rate of change of the Doppler frequency shift and to determine the linear frequency modulation spread characteristics of the received signal in the time-frequency plane. The macroscopic kinematic parameters are acquired in real time by the onboard train automatic control system, possessing high precision and being unaffected by wireless channel interference. These parameters are used to construct a coordinate transformation reference consistent with actual physical motion in a fractional-order space.

[0043] In this embodiment, the focus is on the structural diffusion characteristics of the signal in the time-frequency plane, rather than the positional offset of the instantaneous frequency shift. Therefore, when calculating the fractional-order rotation angle, only the instantaneous acceleration of the train is used as the driving parameter. This acceleration describes the slope of the Doppler frequency shift over time, thereby accurately determining the rotation angle of the fractional-order Fourier transform. This allows the signal energy diffusion caused by the train's variable speed operation to be structurally compressed in the transform domain, achieving effective decoupling of the signal diffusion pattern. In contrast, although the train speed determines the absolute offset of the instantaneous frequency shift, it cannot reflect the diffusion law of the signal on the time axis, and therefore is insufficient to complete the structural alignment and energy concentration in the fractional-order space.

[0044] The specific process of algebraic mapping is as follows: the train acceleration is mapped to the Doppler frequency through the constant speed of light, and the frequency change is amplified into the frequency change of the signal using the carrier center frequency; the frequency change is mapped to the fractional rotation degree through the inverse cotangent relation; thus, the rotation degree used for the fractional Fourier transform is obtained, so that the rotation angle θ can accurately reflect the diffusion slope of the signal in the time-frequency plane.

[0045]

[0046] Calculate the fractional rotation angle (in Indicates the center frequency of the carrier. Represents the speed of light. Let represent the inverse cosine function, a represent the train acceleration, and c represent the speed of light.

[0047] The received time-domain signal containing Doppler interference acquired by the radio frequency front end ( This indicates a baseband signal containing Doppler interference. (Representing the time variable); after inputting into the fractional Fourier transform, the rotation degree is called. Corresponding orthogonal kernel function (in Integral operations are performed on the independent variable (representing the fractional domain). (in This represents the transformed signal. This indicates the integration operation. (representing the time differential element), which maps the received time-domain signal to a fractional-order domain signal.

[0048] It should be noted that by rotating the coordinate system along the rotation angle within the fractional-order subspace, the signal energy is projected onto a space orthogonal to the diffusion slope, generating a direct output data state after spatial rotation and dimensionality reduction: a fractional-order characteristic flow in the form of narrowband impulse peaks. This achieves structural decoupling and energy concentration of the time-varying Doppler signal. Specifically, the interference energy, originally torn apart by the ultra-high-speed Doppler effect and dispersed throughout the entire communication frequency band, collapses instantaneously in the fractional-order domain, aggregating into a Dirac Impulse sequence with extremely high energy density and an extremely narrow bandwidth.

[0049] Here, "information energy" refers to the effective characteristic amplitude and geometric volume of rail transit baseband control signaling (such as CBTC data) in phase space evolution. By employing volume-preserving mapping with symplectic integral operators, this "information energy" is ensured to be absolutely conserved when the system forcibly pulls back the phase pulled by interference, completely avoiding the numerical dissipation and weak signal loss caused by traditional linear filters during bias correction. Furthermore, in step S3 (Hamiltonian dynamic evolution) of this invention, this information energy is equivalently mapped to the "volume" of the phase space fluid.

[0050] The space orthogonal to the diffusion slope refers to the constructed optimal fractional-order projection subspace. This space is a new mathematical observation dimension formed by rotating the traditional two-dimensional time-frequency coordinate system by a specific angle. Within this specific orthogonal space, the time-varying Doppler frequency shift (linear frequency modulation diffusion slope) originally caused by extremely rapid motion is completely algebraically decoupled, manifesting as a quasi-static environment where the Doppler effect is "forcibly frozen".

[0051] A multi-stage pipelined architecture for Coordinate Rotation Digital Computation (CORDIC) hardware macrocells is deployed within an FPGA to achieve microsecond-level fractional spatial rotation transformations by replacing complex trigonometric function multiplications with shift and addition operations.

[0052] S2: For non-Gaussian impact disturbances, a nonlinear metric space based on maximizing local correlation entropy is constructed within the fractional subspace; the fractional feature stream is input into the nonlinear metric space, and the impact transient energy is adaptively truncated in algebraic iterations using the extreme decay characteristics of the kernel function to output a clean phase sequence.

[0053] Specifically, an adaptive transverse filter structure is constructed within the processor of the baseband signal, and a local correlation entropy objective function is defined:

[0054]

[0055] in Represents the total measurement value. To express summation, Indicates the sampling point index. Indicates the length of the observation window. Represents an exponential function. This represents the transient residual between the filter output and the desired signal. This represents the kernel width parameter.

[0056] The local correlation entropy objective function is used to measure the deviation between the filter output and the desired signal in each local time window, so as to guide the dynamic weight update of each local time window in the filter output.

[0057] Initiate the iterative update program for filter tap weights: In each clock cycle, calculate the transient residual of the current local time window in real time, and form dynamic weights based on the transient residuals through exponential decay, which are used to adjust the filter tap weights so that the weights corresponding to sampling points with larger residuals are automatically reduced.

[0058] Let the residual of the current sampling point be... And substitute it into the formula containing the decay factor:

[0059]

[0060] in This indicates dynamic weighting.

[0061] When a sudden arc pulse occurs in the pantograph contact network, the absolute value of the residual corresponding to this transient state is... ;in Represents absolute value. Indicates a tendency towards, It represents infinity.

[0062] The adaptive truncation includes, when a sudden arc pulse occurs in the contact network, causing the transient residual to reach an extreme value, attenuating the dynamic weight to a value of zero, thereby automatically eliminating the local time window of non-Gaussian impact energy without the need for an external high-level trigger for pulse detection; and outputting the pure phase sequence stripped of non-Gaussian impact energy.

[0063] The exponential mapping lookup table (LUT) of the Gaussian kernel function is pre-programmed into the on-chip block random access memory (BRAM) of the FPGA. The processor uses the residual as the address bus index and directly reads the corresponding decay factor within one clock cycle.

[0064] S3: Map the phase characteristics of the pure phase sequence to regular conjugate variables in Hamiltonian phase space, and reconstruct the communication correction into a dynamic evolution process; use the volume-preserving symplectic integral operator to perform evolutionary solution on the variables, and restore the deviated trajectory to the steady-state orbit under the premise of ensuring the absolute conservation of the intrinsic energy of the signal, thus completing the signal demodulation.

[0065] Reconstructing communication correction as a dynamic evolution process includes: establishing two independent register spaces in the receiver; storing the instantaneous phase extracted from the pure phase sequence and defining it as a generalized coordinate. (in (representing the dynamic position state variable), its instantaneous angular frequency is stored and defined as generalized momentum. (in (Representing dynamic momentum state variables). By mapping the pure phase sequence to generalized coordinates and momentum, the signal deviation behavior is abstracted as the evolution trajectory of the dynamic state, so that signal correction no longer relies on fixed algorithms or simple error feedback, but adaptively recovers according to physical laws. Introducing the transient phase characteristics of communication signals into the Hamiltonian dynamics framework enables the subsequent volume-preserving symplectic integral solution to achieve automatic correction of the deviation trajectory while ensuring the conservation of information energy. This achieves steady-state self-healing of the signal trajectory, thereby improving the demodulation accuracy and robustness of rail transit communication systems in high-speed, low signal-to-noise ratio, and multi-interference environments, while providing a quantifiable physical basis for cross-layer closed-loop collaboration.

[0066] The specific definition logic is as follows: The generalized coordinate is defined as the instantaneous phase q of the received signal at the sampling moment. In physical mapping, phase represents the angular position of the signal in the circular motion of the constellation diagram. Treating it as a coordinate quantity can accurately describe the spatial offset pose of the synchronization loop relative to the reference phase. Generalized momentum is defined as the instantaneous angular frequency p of the signal, used to quantify the rate of change of phase over time. Within the Hamiltonian mechanics framework, momentum reflects the inertia of the system in maintaining its current state of motion. In this embodiment, it represents the phase rotation energy caused by the Doppler effect or local oscillator deviation. By defining phase (position) and frequency (momentum) as a pair of canonical conjugate variables, the complex carrier synchronization problem is successfully reconstructed into a problem within the Hamiltonian energy function. The dynamic evolution process of a particle under constraints.

[0067] It's worth noting that traditional communication algorithms use linear damped filters to filter arc interference. For example, when a pendulum is kicked by an arc pulse (severe phase jitter), a traditional filter will forcibly pull it back in the water (increasing damping). The result is that although the jitter subsides, the pendulum's intrinsic energy is completely depleted, leading to the direct loss of weak signals (loosening of lock).

[0068] After defining q and p as canonical conjugate variables, we can invoke the highly advanced "symplectic integral operator" in mathematics. The ironclad rule of symplectic geometry is that the area (energy) of the system is absolutely conserved during evolution in phase space. This means that even if the arc significantly deviates the signal phase, the algorithm does not generate any artificial numerical dissipation during the entire calculation process of "pulling" it back to its steady-state trajectory. The signal perfectly returns to the synchronization point, as if sliding in a frictionless vacuum.

[0069] Construct the Hamiltonian function to characterize the total energy of a communication synchronization system: defined as the algebraic sum of the system's kinetic and potential energy terms.

[0070]

[0071] in Represents the total energy function of the system. The transpose matrix representing the generalized momentum. The matrix representing the inverse of the system's equivalent inertia matrix. This represents the phase-detection constraint potential energy function.

[0072] The transpose matrix of generalized momentum represents the sum of the "severity of frequency offset" of all communication subcarriers in the entire system. Because high-speed rail communication (such as the OFDM technology used in 5G) operates not on a single frequency, but with hundreds or thousands of frequency channels operating simultaneously, we arrange the frequency offsets of all channels into a long queue (matrix). The so-called "transpose" is simply a mathematical way of turning this vertical queue horizontally for subsequent summarization and multiplication in order to calculate the total energy. The baseband processor captures the instantaneous frequencies of all active subcarriers in the current communication link in real time and compares them with the ideal frequency of the local standard crystal oscillator to obtain the frequency offset value for each channel. These frequency offset values ​​are arranged into a high-dimensional data array according to channel order, and when used in energy calculations, their data structure is flipped from "columns" to "rows," resulting in the transpose matrix.

[0073] The inverse of the system's equivalent inertia matrix represents the "flexibility" or "sluggishness" weight of the receiver's tracking of signal frequency changes. It's like adding a "personality label" to the aforementioned frequency offset, determining how much destructive energy the same magnitude of frequency offset will generate in our system. This is extracted from the hardware / software parameters of the receiver's internal loop filter. In receiver design, loop filters have fixed engineering parameters such as damping factor, proportional gain, and integral gain, which are originally used to filter out noise. We extract these inherent engineering parameters and construct them into a grid feature library (inertia matrix) representing the "system tracking resistance" along the subcarrier dimension. Then, we use a low-level algorithm to calculate the "reciprocal" (inverse matrix) of this feature library.

[0074] The phase detection constraint potential energy function is analogous to an invisible "gravitational funnel" or "spring trap." At the bottom of the funnel is the ideal state of perfect signal synchronization without error. When the arc interference from the pantograph "kicks" the signal phase away, the phase climbs up the funnel wall; the higher the position, the greater the potential energy. The role of this potential energy function is to constantly generate a downward "pull," forcing those stray signal phases to eventually slide back to the perfect synchronization point at the bottom of the funnel. This is derived from the electronic characteristic curve of the phase detector, a core component of a communication receiver. The phase detector acts like a referee, specifically measuring the error between the received signal phase and the local standard phase; the larger the error, the stronger the output correction voltage. We perform a physical cumulative integral mapping of this nonlinear relationship between "error and output voltage" (usually manifested as a sinusoidal electronic characteristic) at the software level. In other words, we translate the phase detector's "hardware error measurement and force generation" process into a potential energy topography map of "a particle climbing a slope and accumulating energy" in physics.

[0075] The system's kinetic energy term is characterized as a generalized quadratic momentum form weighted by the inverse of the equivalent inertia matrix, used to quantify the frequency offset drift rate; the system's potential energy term is characterized as a nonlinear function determined by the phase-locked loop (PLL) phase detection constraint characteristics. Through software modeling, the original electronic phase tracking process based on the PLL is equivalently transformed into a rigid body in a gravitational potential field. The physical process of forced vibration in the middle is used to establish the computational boundary condition of absolute energy conservation for subsequent anti-interference demodulation.

[0076] Furthermore, the solution is performed using the symplectic integral operator with volume-preserving mapping, which includes: in the loop routine for performing carrier phase recovery, the traditional forward Euler difference algorithm is abandoned, and the symplectic integral solution module based on the implicit midpoint rule is called for iterative evolution.

[0077] Read the current number Phase of one clock cycle and angular frequency By calculating the partial derivatives of the Hamiltonian function with respect to generalized momentum and generalized coordinates at the precise midpoint between the current state and the next unknown state, the state variables for the next clock cycle are cross-referenced and updated.

[0078]

[0079]

[0080] in Indicates the digital sampling time step. and These represent the partial derivative instructions with respect to momentum and coordinates, respectively. This represents the midpoint value of the state. This represents the generalized coordinate (position) at step k+1. Let represent the generalized momentum at step k+1.

[0081] The execution constraint is: to maintain the determinant of the state transition Jacobian matrix at 1 in algebra, to ensure that the phase space fluid is volume-preservingly mapped, so that the effective information energy volume of the signal will not be dissipated due to the truncation error of numerical integration during the process of the phase sequence being pulled back to the steady-state reference point by point.

[0082] It is worth noting that, in order to achieve accurate adaptive phase restoration and energy conservation of signals in high-speed, multi-interference rail transit communication environments, traditional forward Euler difference methods are prone to numerical truncation errors during iteration, causing the phase trajectory to deviate from the steady state and signal energy to dissipate, thus reducing demodulation accuracy. By employing an implicit midpoint symplectic integral operator with volume-preserving mapping, the iterative evolution of the signal state is mapped to a strictly conserved Hamiltonian dynamical system, ensuring that the volume of each state update in phase space remains constant, guaranteeing that the effective information energy of the signal is not lost due to numerical errors. The phase recovery problem of communication signals is transformed into a physical dynamic iterative solution. Self-healing of the steady-state trajectory is achieved through midpoint calculation and cross-partial derivatives, while simultaneously considering iterative accuracy and real-time performance. This allows the system to maintain high robustness and high-precision demodulation even in the face of rapid changes and sudden interference.

[0083] It's important to understand that the implicit midpoint symplectic integral has been widely validated as a volume-preserving, long-term stable numerical integration method, capable of accurately approximating the midpoint state within a finite step size. Combined with the discrete sampling time step in rail transit communication systems, the midpoint state can be obtained through a small number of iterations within each sampling period, ensuring accurate and reliable calculations of the momentum and coordinate partial derivatives of the Hamiltonian function, thereby achieving trajectory self-healing and energy conservation of signal information. This can be implemented in embedded processors or FPGAs.

[0084] The total Hamiltonian energy obtained based on the symplectic integral iterative evolution can be accurately calculated within each sampling period. During the solution evolution of the symplectic integral, an energy monitoring process is established to calculate in real time the absolute deviation between the actually observed total Hamiltonian energy and the preset, interference-free ideal total energy in the register, which is used as the Hamiltonian energy residual. This deviation value can be transmitted to the MAC layer processor in real time via an internal high-speed interface, enabling the link layer to respond quickly at both the hardware and software levels.

[0085] in Indicates the system's energy deviation. This represents the total energy actually observed. This represents the preset, interference-free ideal total energy within the register.

[0086] The Hamiltonian energy residual is sent to the Media Access Control (MAC) layer processor as a confidence metric flag for the physical layer. When the flag value exceeds a preset security tolerance threshold, an interrupt service routine is immediately executed, adaptively increasing the redundant check bits of the forward error correction coding to achieve cross-layer closed-loop collaboration.

[0087] It should be noted that the FPGA's embedded digital signal processing (DSP) slice array is used to construct a parallel multiply-accumulate (MAC) matrix, which is dedicated to high-speed solving of the partial derivative difference equation of implicit symplectic integral. Through the above hardware and software co-design, it is ensured that the high-dimensional dynamics algorithm meets the extremely low latency requirements of rail transit communication.

[0088] This embodiment also provides a wireless anti-interference communication system for rail transit, including:

[0089] The acquisition unit extracts the real-time macroscopic kinematic parameters of the train and then algebraically maps these macroscopic kinematic parameters into dynamic rotation degrees of a fractional-order space. The received baseband signal tensor is spatially rotated using the dynamic rotation degrees, which decouples and forces the broadband signal diverging from the time-varying Doppler frequency shift within a specific fractional-order subspace, outputting a fractional-order feature stream with concentrated energy.

[0090] The adjustment unit constructs a nonlinear metric space based on maximizing local correlation entropy within the fractional-order subspace for non-Gaussian impact interference. The fractional-order feature stream is input into the nonlinear metric space, and the impact transient energy is adaptively truncated in algebraic iterations using the extreme decay characteristics of the kernel function to output a pure phase sequence.

[0091] The output unit maps the phase characteristics of the pure phase sequence to regular conjugate variables in Hamiltonian phase space, reconstructing the communication correction into a dynamic evolution process; it uses a volume-preserving symplectic integral operator to perform evolutionary solutions on the variables, restoring the deviated trajectory to a steady-state orbit while ensuring the absolute conservation of the signal's intrinsic energy, thus completing signal demodulation.

[0092] This embodiment also provides a computer device applicable to the rail transit wireless anti-interference communication method, including: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the rail transit wireless anti-interference communication method proposed in the above embodiment.

[0093] The computer device can be a terminal, comprising a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0094] This embodiment also provides a storage medium storing a computer program, which, when executed by a processor, implements the method for implementing wireless anti-interference communication in rail transit as proposed in the above embodiments. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0095] In summary, this invention achieves structural decoupling and energy concentration of the received signal within a fractional-order subspace by mapping the instantaneous acceleration algebraically obtained from the train's real-time speed information to a fractional-order rotation degree; it utilizes local correlation entropy to construct an adaptive nonlinear metric mechanism to automatically eliminate non-Gaussian transient impact signals, generating a pure phase sequence; it maps the pure phase sequence to the generalized coordinates and momentum of a Hamiltonian dynamic system, and employs volume-preserving symplectic integral iterative evolution to achieve adaptive repair and steady-state recovery of trajectory deviations, ensuring the conservation of signal information energy; during this process, it monitors the total Hamiltonian energy deviation in real time and feeds the deviation back to the link layer as a physical layer confidence indicator, adaptively increasing forward error correction redundancy when necessary to achieve closed-loop collaboration between the physical layer and the link layer. Through these technical means, this invention can achieve high-precision signal decoupling, transient impact suppression, trajectory self-healing, and link protection in high-speed, multi-interference rail transit communication environments, significantly improving the steady-state reliability and anti-interference performance of the communication system.

[0096] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A wireless anti-interference communication method for rail transit, characterized in that: This includes extracting the real-time macroscopic kinematic parameters of the train, algebraically mapping the macroscopic kinematic parameters into dynamic rotation degrees of a fractional space, and using the dynamic rotation degrees to perform spatial rotation on the received baseband signal tensor, thereby decoupling and forcibly aggregating the broadband signal diverged by the time-varying Doppler frequency shift in a specific fractional subspace, and outputting a fractional characteristic flow with concentrated energy. For non-Gaussian impact disturbances, a nonlinear metric space based on maximizing local correlation entropy is constructed within the fractional subspace; the fractional feature stream is input into the nonlinear metric space, and the impact transient energy is adaptively truncated in algebraic iterations using the extreme decay characteristics of the kernel function to output a clean phase sequence. The phase characteristics of the pure phase sequence are mapped to regular conjugate variables in Hamiltonian phase space, and the communication correction is reconstructed into a dynamic evolution process. The symplectic integral operator with volume-preserving mapping is used to perform evolutionary solution on the variables. Under the premise of ensuring the absolute conservation of the intrinsic energy of the signal, the deviated trajectory is restored to the steady-state orbit, and the signal demodulation is completed.

2. The rail transit wireless anti-interference communication method as described in claim 1, characterized in that: The macroscopic kinematic parameters include instantaneous velocity acquired in real time through a bus interface with the train automatic control system, and instantaneous acceleration of the train along the track calculated based on the instantaneous velocity.

3. The rail transit wireless anti-interference communication method as described in claim 2, characterized in that: The algebraic mapping includes mapping the train acceleration to a Doppler frequency using the constant speed of light, and amplifying the frequency change into a signal frequency change using the carrier center frequency; and mapping the frequency change to a fractional rotation degree using the inverse cotangent relation. The received time-domain signal with Doppler interference acquired by the radio frequency front end is used as the baseband signal. After being input into the fractional Fourier transform, the orthogonal kernel function corresponding to the rotation degree is called to perform integration operation, and the received time-domain signal is mapped to the fractional domain signal. By rotating the coordinate system within the fractional-order subspace along the rotation angle, the signal energy is projected onto a space orthogonal to the diffusion slope, generating a fractional-order characteristic flow in the form of a narrowband impulse peak, thereby achieving structural decoupling and energy concentration of the time-varying Doppler signal.

4. The rail transit wireless anti-interference communication method as described in claim 3, characterized in that: The nonlinear metric space includes constructing an adaptive transverse filter structure within the processor of the baseband signal and defining a local correlation entropy objective function to measure the deviation between the filter output and the desired signal in each local time window, so as to guide the dynamic weight update of each local time window in the filter output. Within each clock cycle, the transient residual of the current local time window is calculated in real time, and dynamic weights are formed by exponential decay based on the transient residuals. These weights are used to adjust the filter tap weights so that the weights corresponding to sampling points with larger residuals are automatically reduced. The adaptive truncation includes, when a sudden arc pulse occurs in the contact network, causing the transient residual to reach an extreme value, attenuating the dynamic weight to a value of zero, thereby automatically eliminating the local time window of non-Gaussian impact energy without the need for an external high-level trigger for pulse detection; and outputting the pure phase sequence stripped of non-Gaussian impact energy.

5. The rail transit wireless anti-interference communication method as described in claim 4, characterized in that: The process of reconstructing communication correction into a dynamic evolution process includes: establishing two independent register spaces in the receiver; storing and defining the instantaneous phase extracted from the pure phase sequence as generalized coordinates, and storing and defining its instantaneous angular frequency as generalized momentum; Construct the Hamiltonian function to characterize the total energy of a communication synchronization system: defined as the algebraic sum of the system's kinetic and potential energy terms; Among them, the system kinetic energy term is characterized as a generalized momentum quadratic form weighted by the inverse of the equivalent inertia matrix, which is used to quantify the frequency offset drift rate; the system potential energy term is characterized as a nonlinear function determined by the phase-locked loop phase detection constraint characteristics.

6. The rail transit wireless anti-interference communication method as described in claim 5, characterized in that: The solution process using the volume-preserving symplectic integral operator includes: in the loop routine for performing carrier phase recovery, calling the symplectic integral solution module based on the implicit midpoint rule for iterative evolution; The phase and angular frequency states of the current clock cycle are read, and the state quantities of the next clock cycle are cross-derived and updated by calculating the partial derivatives of the Hamiltonian function with respect to generalized momentum and generalized coordinates at the precise midpoint between the current state and the next unknown state. The execution constraint is: to maintain the determinant of the state transition Jacobian matrix at 1 in algebra, to ensure that the phase space fluid is volume-preservingly mapped, so that the effective information energy volume of the signal will not be dissipated due to the truncation error of numerical integration during the process of the phase sequence being pulled back to the steady-state reference point by point.

7. The rail transit wireless anti-interference communication method as described in claim 6, characterized in that: During the solution evolution of the symplectic integral, an energy monitoring process is established to calculate in real time the absolute deviation between the actual observed total Hamiltonian energy and the preset uninterrupted ideal total energy in the register, which is used as the Hamiltonian energy residual. The Hamiltonian energy residual is sent to the medium access control layer processor as a confidence metric flag of the physical layer. When the value of the flag bit exceeds the preset security tolerance threshold, the interrupt service routine is executed immediately, and redundant check bits of the forward error correction code are adaptively increased to achieve cross-layer closed-loop collaboration.

8. A wireless anti-interference communication system for rail transit, based on the wireless anti-interference communication method for rail transit according to any one of claims 1 to 7, characterized in that: include, The acquisition unit extracts the real-time macroscopic kinematic parameters of the train and then algebraically maps the macroscopic kinematic parameters into dynamic rotation degrees of a fractional space. The received baseband signal tensor is spatially rotated using the dynamic rotation degrees, and the broadband signal diverged by the time-varying Doppler frequency shift is decoupled and forcibly aggregated in a specific fractional subspace, outputting a fractional characteristic flow with concentrated energy. The adjustment unit, for non-Gaussian impact disturbance, constructs a nonlinear metric space based on maximizing local correlation entropy within the fractional subspace; inputs the fractional feature stream into the nonlinear metric space, and utilizes the extreme decay characteristics of the kernel function to adaptively truncate the impact transient energy in algebraic iteration, outputting a pure phase sequence; The output unit maps the phase characteristics of the pure phase sequence to regular conjugate variables in Hamiltonian phase space, and reconstructs communication correction into a dynamic evolution process. The variable is solved by using a volume-preserving symplectic integral operator. Under the premise of ensuring the absolute conservation of the intrinsic energy of the signal, the deviated trajectory is restored to the steady-state orbit, and the signal demodulation is completed.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the rail transit wireless anti-interference communication 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 executed by the processor, it implements the steps of the rail transit wireless anti-interference communication method according to any one of claims 1 to 7.

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