Gsm-r multi-path interference detection method and device

Abstract

The application discloses a GSM-R multi-path interference detection method and device, wherein the method comprises the following steps: performing channelization processing on wideband in-phase / quadrature I / Q data collected along a railway to obtain a plurality of GSM-R channel I / Q data; through resampling processing, a plurality of GSM-R channel I / Q data with a sampling rate matched with a GSM-R symbol rate is obtained; a frequency correction channel FCCH burst signal is extracted from the plurality of GSM-R channel I / Q data after resampling; a phase sequence of the FCCH burst signal is extracted, and the phase sequence is subjected to differential processing to obtain a phase difference sequence; the phase difference sequence is subjected to frequency domain transformation to obtain a phase difference spectrum; frequency domain peak value distribution characteristics of the phase difference spectrum are compared and analyzed with preset multi-path interference frequency domain characteristics to obtain a GSM-R multi-path interference detection result. The application can realize accurate detection of GSM-R multi-path interference.

Description

Technical Field

[0001] This invention relates to the field of dynamic detection technology in wireless communication, and more particularly to a method and apparatus for detecting GSM-R multipath interference. Background Technology

[0002] The GSM-R (Global System for Mobile Communications – Railway) network, as a dedicated channel for train-to-ground wireless data transmission, undertakes core services such as train operation control information transmission, dispatch command transmission, and emergency communication, and is a key means to ensure railway transportation safety. Unlike the GSM network, the GSM-R communication scenario has significant unique characteristics, with numerous complex terrains such as railway tunnels, bridges, and mountainous areas, among which tunnel scenarios account for a very high proportion.

[0003] The enclosed space inside the tunnel and the walls, which are mostly made of reinforced concrete, make radio signal propagation susceptible to reflection and scattering from the walls, creating a complex multipath propagation environment. This leads to problems such as inter-symbol interference, increased demodulation error rate, and unstable communication links for GSM-R signals. In severe cases, it can cause data transmission delays and interruptions, directly threatening railway traffic safety.

[0004] In addition to tunnel scenarios, similar problems exist on bridges and mountainous sections along railway lines. Signals are blocked by terrain and reflected by multiple obstacles, resulting in frequent multipath interference. Furthermore, during high-speed travel of the dynamic detection vehicle, the signal is easily affected by Doppler frequency shift and instantaneous interference, further exacerbating the difficulty of detecting GSM-R multipath interference.

[0005] Existing GSM-R interference detection methods lack multipath interference detection capabilities, which is clearly insufficient for supporting on-site network maintenance. Summary of the Invention

[0006] This invention provides a GSM-R multipath interference detection method to achieve accurate detection of GSM-R multipath interference. The method includes: The broadband in-phase quadrature I / Q data collected from the railway line are channelized to obtain multiple GSM-R channel I / Q data. Multiple GSM-R channel I / Q data are resampled to obtain multiple GSM-R channel I / Q data with a sampling rate matching the GSM-R symbol rate; Extract the frequency correction channel (FCCH) burst signal from multiple resampled GSM-R channel I / Q data; Extract the phase sequence of the FCCH burst signal, and perform differential processing on the phase sequence to obtain the phase difference sequence; The phase difference sequence is subjected to frequency domain transformation to obtain the phase difference spectrum; The frequency domain peak distribution characteristics of the phase difference spectrum are compared and analyzed with the preset multipath interference frequency domain characteristics to obtain the GSM-R multipath interference detection results.

[0007] This invention also provides a GSM-R multipath interference detection device for accurate detection of GSM-R multipath interference. The device includes: The GSM-R channel extraction module is used to: perform channelization processing on broadband in-phase quadrature I / Q data collected from along the railway line to obtain multiple GSM-R channel I / Q data; The sampling rate calibration module is used to: resample multiple GSM-R channel I / Q data to obtain multiple GSM-R channel I / Q data with a sampling rate that matches the GSM-R symbol rate; The FCCH signal extraction module is used to extract the frequency correction channel FCCH burst signal from multiple resampled GSM-R channel I / Q data. The phase difference calculation module is used to: extract the phase sequence of the FCCH burst signal, perform differential processing on the phase sequence, and obtain a phase difference sequence; The phase difference spectrum calculation module is used to: perform frequency domain transformation on the phase difference sequence to obtain the phase difference spectrum; The GSM-R multipath interference detection module is used to: compare and analyze the frequency domain peak distribution characteristics of the phase difference spectrum with the preset multipath interference frequency domain characteristics to obtain the GSM-R multipath interference detection results.

[0008] This invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-described GSM-R multipath interference detection method.

[0009] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described GSM-R multipath interference detection method.

[0010] This invention also provides a computer program product, which includes a computer program that, when executed by a processor, implements the above-described GSM-R multipath interference detection method.

[0011] Compared with existing GSM-R interference detection schemes that lack multipath interference detection capabilities, this invention, in its embodiment, extracts GSM-R channel signals by channelizing broadband in-phase (in-phase) and quadrature (I / Q) data collected along the railway line. Then, utilizing the inherent single-frequency characteristics of the frequency correction channel (FCCH) burst signal in the GSM-R system, the phase sequence of the FCCH burst signal is differentially transformed and frequency-domain transformed to construct a phase difference spectrum characterizing the phase change pattern. Finally, the frequency domain peak distribution characteristics of the phase difference spectrum are compared and analyzed with preset multipath interference frequency domain characteristics. This enables accurate and efficient detection of multipath interference in high-speed railway movement scenarios, filling a gap in existing GSM-R interference detection schemes. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. 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. In the drawings: Figure 1 This is a flowchart of the GSM-R multipath interference detection method in an embodiment of the present invention; Figure 2 This is a physical structure diagram of a device for implementing the GSM-R multipath interference detection method in an embodiment of the present invention; Figure 3 This is another flowchart of the GSM-R multipath interference detection method in this embodiment of the invention; Figure 4 This is a schematic diagram of the GSM-R multipath interference detection device in an embodiment of the present invention; Figure 5 This is another schematic diagram of the GSM-R multipath interference detection device in an embodiment of the present invention. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0014] To address the problem of frequent multipath interference in railway GSM-R scenarios involving multiple tunnels, complex terrains, and high-speed movement, where existing interference detection capabilities are insufficient, this invention proposes a GSM-R multipath interference detection method that is adapted to railway scenarios involving multiple tunnels, complex terrains, and high-speed movement, offering high detection accuracy and strong anti-interference capabilities, thus filling a gap in the existing technology.

[0015] Figure 1 This is a flowchart of the GSM-R multipath interference detection method in an embodiment of the present invention. Figure 1 As shown, this method can be implemented in the following steps: Step 101: Channelize the broadband in-phase quadrature I / Q data collected from the railway line to obtain multiple GSM-R channel I / Q data. Step 102: Resample multiple GSM-R channel I / Q data to obtain multiple GSM-R channel I / Q data with a sampling rate matching the GSM-R symbol rate; Step 103: Extract the frequency correction channel (FCCH) burst signal from multiple resampled GSM-R channel I / Q data; Step 104: Extract the phase sequence of the FCCH burst signal, and perform differential processing on the phase sequence to obtain the phase difference sequence; Step 105: Perform frequency domain transformation on the phase difference sequence to obtain the phase difference spectrum; Step 106: Compare and analyze the frequency domain peak distribution characteristics of the phase difference spectrum with the preset multipath interference frequency domain characteristics to obtain the GSM-R multipath interference detection results.

[0016] Compared with existing GSM-R interference detection schemes that lack multipath interference detection capabilities, this invention extracts GSM-R channel signals by channelizing broadband in-phase quadrature (I / Q) data collected along the railway line. Then, utilizing the inherent single-frequency characteristics of the frequency correction channel (FCCH) burst signal in the GSM-R system, the phase sequence of the FCCH burst signal is differentially transformed and frequency-domain transformed to construct a phase difference spectrum characterizing the phase change pattern. Finally, the frequency domain peak distribution characteristics of the phase difference spectrum are compared and analyzed with preset multipath interference frequency domain characteristics. This enables accurate and efficient detection of multipath interference in high-speed railway movement scenarios, filling a gap in existing GSM-R interference detection schemes.

[0017] Figure 2 This is a physical structure diagram of a device for implementing the GSM-R multipath interference detection method in an embodiment of the present invention. Figure 2As shown, the physical structure of the device mainly includes: a display unit, a control and calculation unit, a data acquisition unit, and a system power supply. The display unit serves as a human-machine interface, the system power supply serves as an AC220V power input interface, and the data acquisition unit serves as an air interface for receiving radio signals.

[0018] Figure 2 The acquisition unit specifically includes a GSM-R (dedicated) antenna, a preselector, and an RF receiver. The RF receiver is used to down-convert the received signal and perform analog-to-digital conversion to output wideband I / Q data.

[0019] For example, a dedicated GSM-R antenna installed on the roof of the dynamic inspection vehicle receives radio signals along the railway line and transmits them to the interior of the vehicle via a feeder. This dedicated GSM-R antenna uses the same antenna as the onboard train operation control system (e.g., Automatic Train Protection, ATP), is compatible with the GSM-R system's operating frequency band (930-934MHz), and is installed in the same direction as the ATP antenna to ensure that the perceived wireless network status matches the actual application scenario.

[0020] In this embodiment, the signal received by the GSM-R dedicated antenna is input to the preselector via a feeder and then connected to a radio signal acquisition device (e.g., an RF receiver); wherein the preselector operates at a frequency of 929-935MHz.

[0021] In this embodiment, the radio signal acquisition device collects radio signals from the GSM-R band and adjacent bands in real time according to configuration parameters (center frequency, bandwidth), converts the radio frequency signals into wideband I / Q data, and outputs them to the real-time processing unit through a PCIe interface or a 10 Gigabit Ethernet interface. The radio signal acquisition device has preset acquisition parameters: the acquisition frequency band covers the GSM-R band (930-934MHz) and adjacent bands, the sampling rate is set to 6MHz, and the sampling accuracy is 16bit, collecting radio signals along the railway line in real time. During the acquisition process, the radio signal acquisition device performs down-conversion and analog-to-digital conversion on the received radio frequency signals to generate wideband I / Q data (complex form), which is then output to the real-time processing unit at high speed through a PCIe interface or a 10 Gigabit Ethernet interface. The interface supports a transmission rate of ≥10Gbps, ensuring real-time transmission of wideband I / Q data and providing a high-quality data foundation for subsequent channelized extraction of GSM-R signals.

[0022] Figure 2The control and operation unit specifically includes a real-time processing unit and a system controller. The real-time processing unit is used to perform channelization processing, resampling, FCCH extraction, phase difference spectrum calculation, and multipath interference identification on broadband I / Q data. The system controller is used to receive the detection results from the real-time processing unit, process them in conjunction with the positioning data, and drive the display unit. The display unit uses a system display to display the multipath interference detection results, interference intensity level, and interference location distribution map in real time.

[0023] The wideband I / Q data collected by the dynamic testing vehicle covers the GSM-R band and adjacent bands. This data includes not only valid GSM-R communication signals but also out-of-band noise, adjacent channel interference, and spurious signals from non-GSM-R standards. To accurately separate the individual GSM-R channel signals from the wideband I / Q data, an efficient channelization processing algorithm is required.

[0024] First, in this embodiment of the invention, the broadband I / Q data collected from along the railway line is channelized to obtain multiple GSM-R channel I / Q data.

[0025] In one embodiment, a multiphase filtering algorithm is used to channelize broadband I / Q data collected from along the railway line to obtain multiple GSM-R channel I / Q data.

[0026] For example, after receiving wideband I / Q data, a polyphase filtering algorithm is used to channelize the wideband I / Q data, decomposing it into multiple narrowband channel signals. Each narrowband channel corresponds to a GSM-R channel (channel spacing 200kHz), enabling GSM-R signal extraction. Furthermore, the separated GSM-R channel signals are filtered to remove invalid signals with a signal-to-noise ratio below 10dB or those severely interfered with, thus extracting the valid GSM-R channel I / Q data.

[0027] The sampling rate of the GSM-R channel I / Q data output by channelization processing is usually not equal to the symbol rate of the GSM-R system. If the sampling rate and symbol rate do not match, time-domain distortion and spectral distortion will occur during subsequent phase extraction and differential processing of the FCCH signal.

[0028] Therefore, in this embodiment of the invention, multiple GSM-R channel I / Q data are resampled to obtain multiple GSM-R channel I / Q data with a sampling rate matching the GSM-R symbol rate.

[0029] In one embodiment, multiple GSM-R channel I / Q data are resampled using a linear interpolation resampling algorithm to obtain multiple GSM-R channel I / Q data with a sampling rate matching the GSM-R symbol rate.

[0030] For example, based on the GSM-R system symbol rate (270.833kHz), a linear interpolation resampling algorithm is used to resample the extracted effective GSM-R channel I / Q data, precisely adjusting the sampling rate to 270.833kHz. This ensures that the resampled I / Q data is completely matched with the GSM-R system symbol rate, eliminating signal distortion caused by sampling rate mismatch and providing standardized data support for subsequent FCCH extraction and phase difference calculation.

[0031] In the GSM-R frame structure, the FCCH signal carries an all-zero bit sequence. After modulation (e.g., GMSK, Gaussian minimum frequency shift keying), it appears as a pure single-frequency signal (66.7 kHz higher than the carrier center frequency). This pure single-frequency characteristic makes the FCCH signal exhibit a single sharp peak in the frequency domain, which is significantly different from traffic channels and broadcast control channels. Therefore, the FCCH is an ideal signal source for extracting phase information and constructing phase difference spectra.

[0032] In this embodiment of the invention, the frequency correction channel (FCCH) burst signal is extracted from multiple resampled GSM-R channel I / Q data.

[0033] It should be noted that the FCCH signal has a pure single-frequency characteristic, which can be used to accurately locate the position of the FCCH burst signal.

[0034] In one embodiment, based on the GSM-R frame structure, the starting position of the GSM-R frame in the multiple resampled GSM-R channel I / Q data is located using the sliding window autocorrelation method; based on the starting position, the multiple resampled GSM-R channel I / Q data are divided into time slots to determine the position of the TS0 time slot in each GSM-R frame; based on the position of the TS0 time slot, the TS0 time slot signal is extracted from the multiple resampled GSM-R channel I / Q data; frequency domain analysis is performed on the TS0 time slot signal to select the TS0 time slot signal whose spectral characteristics conform to the FCCH characteristics as the FCCH burst signal.

[0035] It should be noted that the sliding window autocorrelation method utilizes the periodic characteristics of the GSM-R frame structure to locate the frame start position by calculating the correlation between the signal and its delayed replica. It is a coarse synchronization method with strong noise resistance. After locating the frame start position, since each GSM-R frame contains a fixed 8 time slots, and the FCCH is fixedly mapped to time slot 0 (TS0), the precise position of each TS0 time slot can be calculated based on the frame start position. Frequency domain analysis of the TS0 time slot signal is performed, and the pure single-spectrum characteristics of the FCCH signal are used for final confirmation.

[0036] For example, based on the resampled GSM-R channel I / Q data, according to the GSM-R frame structure (frame period 4.615ms, 8 time slots per frame), the sliding window autocorrelation method is used to locate the coarse synchronization start position of the GSM-R frame. Then, time slots are divided, with a focus on the TS0 time slot (where the FCCH is located). Frequency domain analysis is performed on the TS0 time slot signal. Utilizing the core characteristics of the FCCH signal—a pure single-frequency signal (66.7kHz higher than the GSM-R carrier center frequency) and no modulation—signal segments with a single sharp peak in the spectrum, peak frequencies conforming to FCCH characteristics, and half-power bandwidth ≤10kHz are selected. Ten consecutive frames are detected; if at least eight frames meet the FCCH signal characteristics, the FCCH location is confirmed as successful, yielding the discrete complex FCCH signal. This effectively avoids false detections caused by channel fading or transient interference. The continuous multi-frame verification mechanism further reduces the risk of occasional false detections in a single frame.

[0037] As a pure single-frequency signal, the ideal phase of the FCCH signal should change linearly with time. When multipath interference is present, the superposition of the direct and reflected signals will cause phase distortion of the received signal. To quantitatively characterize the degree of this phase distortion, it is necessary to extract the phase sequence of the FCCH signal and obtain the phase difference sequence through differential processing. This sequence essentially reflects the instantaneous frequency change of the signal.

[0038] In this embodiment of the invention, the phase sequence of the FCCH burst signal is extracted, and the phase sequence is differentially processed to obtain a phase difference sequence.

[0039] In one embodiment, the phase sequence of the FCCH burst signal is extracted; the phase sequence is de-wound to obtain an unwound phase sequence; and the unwound phase sequence is differentially processed to obtain a phase difference sequence.

[0040] For example, extract the phase sequence of the FCCH discrete complex signal and limit the phase range to... The extracted phase sequence is unwound to eliminate phase jump errors at the ±π boundary, resulting in a smooth unwound phase sequence. Subsequently, the phase difference between adjacent sampling points is calculated on the unwound phase sequence to obtain a continuous phase difference sequence.

[0041] The fluctuation characteristics of phase difference sequences in the time domain are difficult to quantify and distinguish between different types of interference. After transforming the phase difference sequence to the frequency domain through frequency domain transformation, multipath interference will manifest as spectral peaks at specific frequency points, while the spectrum of white noise is relatively flat, which facilitates subsequent feature extraction and automatic identification.

[0042] In this embodiment of the invention, the phase difference sequence is subjected to frequency domain transformation to obtain the phase difference spectrum.

[0043] For example, the phase difference sequence is processed by time-domain windowing and frequency-domain transformation, and the phase difference sequence in the time domain is converted into the phase difference spectrum in the frequency domain using the fast Fourier transform.

[0044] In this embodiment of the invention, the frequency domain peak distribution characteristics of the phase difference spectrum are compared and analyzed with the preset multipath interference frequency domain characteristics to obtain the GSM-R multipath interference detection results.

[0045] In one embodiment, the amplitude spectrum of the phase difference spectrum is extracted to obtain the phase difference amplitude spectrum; noise basis analysis is performed on the phase difference amplitude spectrum to obtain the noise basis of the phase difference amplitude spectrum; based on the noise basis, frequency domain peak distribution features are extracted from the phase difference amplitude spectrum; the extracted frequency domain peak distribution features are compared and analyzed with preset multipath interference frequency domain features to obtain GSM-R multipath interference detection results.

[0046] For example, the amplitude spectrum of the phase difference spectrum is extracted to obtain the phase difference amplitude spectrum. Noise basis analysis is performed on the phase difference amplitude spectrum. Continuous frequency points without obvious peaks in the phase difference amplitude spectrum are selected, and the average amplitude of these frequency points is calculated and used as the noise basis.

[0047] In one embodiment, the phase difference amplitude spectrum is normalized to obtain a normalized phase difference amplitude spectrum; noise floor analysis is performed on the normalized phase difference amplitude spectrum to obtain the noise floor of the normalized phase difference amplitude spectrum.

[0048] For example, normalizing the phase difference amplitude spectrum calibrates the peak value to 0dB, eliminating the influence of signal intensity on the spectral characteristics and yielding a normalized phase difference amplitude spectrum that clearly presents the spectral distortion characteristics caused by multipath interference. Noise floor analysis is then performed on the normalized phase difference amplitude spectrum to obtain its noise floor, providing a threshold basis for subsequent effective peak identification and multipath determination.

[0049] In an ideal environment free of multipath interference, the phase difference spectrum exhibits only a single main lobe. However, when multipath interference is present, due to the superposition effect of the direct and reflected signals, multiple secondary peaks appear in the phase difference spectrum in addition to the main lobe, and the ratio of the main lobe peak value to the secondary peak amplitude decreases. Based on this physical mechanism, one embodiment determines the presence of multipath interference by detecting the presence of secondary peaks in the phase difference spectrum and calculating the peak-to-sidelobe ratio (i.e., the main-to-sidelobe power ratio).

[0050] In one embodiment, the frequency domain peak distribution characteristics include: the presence of a secondary peak and the peak-to-sidelobe ratio; the preset multipath interference frequency domain characteristics include: the presence of at least one secondary peak and the peak-to-sidelobe ratio being less than a preset threshold; if a secondary peak exists in the phase difference spectrum and the peak-to-sidelobe ratio is less than a preset power threshold, then the GSM-R multipath interference detection result is that multipath interference exists.

[0051] For example, based on the noise floor, frequency domain peak distribution features are extracted from the phase difference amplitude spectrum, including the presence of secondary peaks and the peak-to-sidelobe ratio. The extracted frequency domain peak distribution features are then compared with preset multipath interference frequency domain features: if the phase difference spectrum has only a single main lobe and no secondary peaks, it is determined that there is no multipath interference; if there is at least one secondary peak and the peak-to-sidelobe ratio is less than a preset threshold, it is determined that multipath interference exists.

[0052] Among them, the secondary peak is defined as the non-main lobe peak whose amplitude exceeds 1.5 times the noise floor, and the peak sidelobe ratio is the ratio of the main lobe peak power to the average amplitude of all secondary peaks, accurately capturing the spectral characteristics corresponding to multipath interference.

[0053] In one embodiment, if there is at least one secondary peak and the peak-to-sidelobe ratio is less than 10 dB, it is determined that multipath interference exists.

[0054] In one embodiment, the frequency domain peak distribution characteristics further include: the number of secondary peaks and the frequency domain spacing of the spectral peaks; after the GSM-R multipath interference detection result indicates the presence of multipath interference, the intensity level of the GSM-R multipath interference is determined based on the number of secondary peaks and the frequency domain spacing of the spectral peaks; wherein, the number of secondary peaks is positively correlated with the intensity of the GSM-R multipath interference, and the frequency domain spacing of the spectral peaks is positively correlated with the intensity of the GSM-R multipath interference.

[0055] For example, the core feature parameters for extracting the phase difference spectrum also include: the number of secondary peaks and the frequency spacing between spectral peaks. Interference intensity is graded based on the number of secondary peaks and the frequency spacing between spectral peaks: the more secondary peaks and the larger the frequency spacing, the higher the multipath interference intensity.

[0056] In addition, the real-time location data obtained by the vehicle's onboard positioning system can be combined to simultaneously output the multipath interference detection results, interference intensity level, and interference location information to the human-machine interface.

[0057] Figure 3 This is another flowchart of the GSM-R multipath interference detection method in an embodiment of the present invention. Figure 3As shown, the dynamic detection vehicle continuously travels along the railway line, repeatedly performing the following steps: First, it receives radio signals, collects broadband I / Q data, and extracts GSM-R signals through channelization, completing real-time acquisition of GSM-R band signals along the railway line; then, through resampling, it achieves sampling rate conversion, FCCH positioning, phase extraction and dewinding, phase difference and spectrum calculation, phase difference spectrum normalization, noise floor calculation, multipath feature extraction, multipath interference judgment and classification, and multipath interference judgment result output, realizing dynamic full-coverage detection of multipath interference in the GSM-R network along the railway line, providing accurate data support for railway GSM-R network operation and maintenance and anti-multipath interference optimization.

[0058] The GSM-R multipath interference detection method in this embodiment of the invention accurately extracts GSM-R signals by channelizing broadband I / Q data and uniformly resampling them to the standard sampling rate. It combines reliable acquisition of multiple consecutive FCCH frames, phase dewinding, and phase difference calculation to construct a phase difference spectrum. By utilizing spectral features, it achieves automatic identification and intensity classification of multipath interference. It can realize dynamic, real-time, and high-sensitivity multipath interference detection along the railway line in complex environments such as tunnels, effectively improving the accuracy of multipath interference identification and better meeting the needs of railway GSM-R operation and maintenance.

[0059] The GSM-R multipath interference detection method provided in this invention has at least the following beneficial effects: (1) High accuracy of multipath interference identification: GSM-R signals are extracted by broadband I / Q data channelization, and effective signals and spurious interference are accurately separated; relying on the pure single-frequency characteristics of FCCH and phase difference spectrum calculation, phase distortion caused by weak multipath can be accurately captured, effectively distinguishing noise from weak multipath interference, and the multipath interference identification accuracy is high and the false detection rate is low.

[0060] (2) Strong anti-interference and robustness: It is suitable for the complex electromagnetic environment along the railway. The FCCH extraction link is verified by continuous multi-frame verification (continuous detection of 10 frames of signal, if ≥8 of them meet the FCCH signal characteristics), avoiding false detection and missed detection caused by instantaneous interference and fast channel fading; phase dewinding and differential spectrum normalization processing further suppress out-of-band noise and instantaneous spurious interference, and can work stably in the high-speed moving scenario of dynamic detection vehicle.

[0061] (3) Excellent real-time performance and dynamic coverage: The radio signal acquisition and real-time processing unit transmits data through PCIe interface or 10 Gigabit Ethernet interface. The interface supports a transmission rate of ≥10Gbps. The channel extraction, resampling and multipath identification processes are completed in real time. When mounted on a dynamic detection vehicle, it can realize full coverage dynamic detection of GSM-R multipath interference along the railway line and solve the problem of missed detection at fixed points.

[0062] (4) High practicality and good adaptability: It is fully compatible with the GSM-R frame structure and signal characteristics. The core technologies (FCCH extraction, phase difference calculation, etc.) can be directly integrated into the dynamic detection system without major modifications to the existing hardware. The multipath identification results combined with the location data output can directly provide accurate data support for the optimization of GSM-R network anti-multipath interference.

[0063] This invention also provides a GSM-R multipath interference detection device, as described in the following embodiments. Since the principle by which this device solves the problem is similar to that of the GSM-R multipath interference detection method, the implementation of this device can refer to the implementation of the GSM-R multipath interference detection method; repeated details will not be elaborated further.

[0064] Figure 4 This is a schematic diagram of a GSM-R multipath interference detection device in an embodiment of the present invention. Figure 4 As shown, the device includes: GSM-R channel extraction module 401 is used to: perform channelization processing on broadband in-phase quadrature I / Q data collected from along the railway line to obtain multiple GSM-R channel I / Q data; The sampling rate calibration module 402 is used to: resample multiple GSM-R channel I / Q data to obtain multiple GSM-R channel I / Q data with a sampling rate matching the GSM-R symbol rate; FCCH signal extraction module 403 is used to extract the frequency correction channel FCCH burst signal from multiple resampled GSM-R channel I / Q data; The phase difference calculation module 404 is used to: extract the phase sequence of the FCCH burst signal, perform differential processing on the phase sequence, and obtain a phase difference sequence; The phase difference spectrum calculation module 405 is used to: perform frequency domain transformation on the phase difference sequence to obtain the phase difference spectrum; The GSM-R multipath interference detection module 406 is used to: compare and analyze the frequency domain peak distribution characteristics of the phase difference spectrum with the preset multipath interference frequency domain characteristics to obtain the GSM-R multipath interference detection result.

[0065] In one embodiment, the GSM-R channel extraction module 401 is specifically used for: By using a multiphase filtering algorithm, broadband I / Q data collected from along the railway line is channelized to obtain multiple GSM-R channel I / Q data.

[0066] In one embodiment, the sampling rate calibration module 402 is specifically used for: By using a linear interpolation resampling algorithm, multiple GSM-R channel I / Q data are resampled to obtain multiple GSM-R channel I / Q data with a sampling rate matching the GSM-R symbol rate.

[0067] In one embodiment, the FCCH signal extraction module 403 is specifically used for: Based on the GSM-R frame structure, the starting position of the GSM-R frame in the multiple resampled GSM-R channel I / Q data is located using the sliding window autocorrelation method; Based on the starting position, the resampled GSM-R channel I / Q data are divided into time slots to determine the position of the TS0 time slot in each GSM-R frame; Based on the location of the TS0 time slot, the TS0 time slot signal is extracted from the resampled GSM-R channel I / Q data; Frequency domain analysis is performed on the TS0 time slot signal to select TS0 time slot signals whose spectral characteristics conform to FCCH characteristics as FCCH burst signals.

[0068] In one embodiment, the phase difference calculation module 404 is specifically used for: Extract the phase sequence of the FCCH burst signal; The phase sequence is unwound to obtain an unwound phase sequence; The unwound phase sequence is differentially processed to obtain a phase difference sequence.

[0069] In one embodiment, the GSM-R multipath interference detection module 406 is specifically used for: Extract the amplitude spectrum of the phase difference spectrum to obtain the phase difference amplitude spectrum; Noise floor analysis is performed on the phase difference amplitude spectrum to obtain the noise floor of the phase difference amplitude spectrum; Based on the noise floor, frequency domain peak distribution features are extracted from the phase difference amplitude spectrum; The extracted frequency domain peak distribution features are compared and analyzed with the preset multipath interference frequency domain features to obtain the GSM-R multipath interference detection results.

[0070] In one embodiment, the GSM-R multipath interference detection module 406 is specifically used for: The phase difference amplitude spectrum is normalized to obtain a normalized phase difference amplitude spectrum. Noise basis analysis is performed on the normalized phase difference amplitude spectrum to obtain the noise basis of the normalized phase difference amplitude spectrum.

[0071] In one embodiment, the frequency domain peak distribution characteristics include: the presence of secondary peaks and the peak-to-sidelobe ratio; The preset multipath interference frequency domain characteristics include: the existence of at least one secondary peak and the peak-to-sidelobe ratio being less than a preset threshold. The GSM-R multipath interference detection module 406 is specifically used for: If a secondary peak exists in the phase difference spectrum and the peak-to-sidelobe ratio is less than the preset power threshold, then the GSM-R multipath interference detection result indicates the presence of multipath interference.

[0072] Figure 5 This is another schematic diagram of the GSM-R multipath interference detection device in an embodiment of the present invention.

[0073] In one embodiment, the frequency domain peak distribution characteristics further include: the number of secondary peaks and the frequency domain spacing of spectral peaks; like Figure 5 As shown, Figure 4 The device also includes a GSM-R multipath interference assessment module 501, used for: The intensity level of GSM-R multipath interference is determined based on the number of secondary peaks and the frequency domain spacing of the spectral peaks; among them, the number of secondary peaks is positively correlated with the intensity of GSM-R multipath interference, and the frequency domain spacing of the spectral peaks is also positively correlated with the intensity of GSM-R multipath interference.

[0074] This invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-described GSM-R multipath interference detection method.

[0075] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described GSM-R multipath interference detection method.

[0076] This invention also provides a computer program product, which includes a computer program that, when executed by a processor, implements the above-described GSM-R multipath interference detection method.

[0077] Compared with existing GSM-R interference detection schemes that lack multipath interference detection capabilities, this invention extracts GSM-R channel signals by channelizing broadband in-phase quadrature (I / Q) data collected along the railway line. Then, utilizing the inherent single-frequency characteristics of the frequency correction channel (FCCH) burst signal in the GSM-R system, the phase sequence of the FCCH burst signal is differentially transformed and frequency-domain transformed to construct a phase difference spectrum characterizing the phase change pattern. Finally, the frequency domain peak distribution characteristics of the phase difference spectrum are compared and analyzed with preset multipath interference frequency domain characteristics. This enables accurate and efficient detection of multipath interference in high-speed railway movement scenarios, filling a gap in existing GSM-R interference detection schemes.

[0078] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0079] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0080] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0081] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0082] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for detecting GSM-R multipath interference, characterized in that, include: The broadband in-phase quadrature I / Q data collected from the railway line are channelized to obtain multiple GSM-R channel I / Q data. Multiple GSM-R channel I / Q data are resampled to obtain multiple GSM-R channel I / Q data with a sampling rate matching the GSM-R symbol rate; Extract the frequency correction channel (FCCH) burst signal from multiple resampled GSM-R channel I / Q data; Extract the phase sequence of the FCCH burst signal, and perform differential processing on the phase sequence to obtain the phase difference sequence; The phase difference sequence is subjected to frequency domain transformation to obtain the phase difference spectrum; The frequency domain peak distribution characteristics of the phase difference spectrum are compared and analyzed with the preset multipath interference frequency domain characteristics to obtain the GSM-R multipath interference detection results.

2. The method as described in claim 1, characterized in that, The broadband I / Q data collected along the railway line is channelized to obtain multiple GSM-R channel I / Q data, including: By using a multiphase filtering algorithm, broadband I / Q data collected from along the railway line is channelized to obtain multiple GSM-R channel I / Q data.

3. The method as described in claim 1, characterized in that, Multiple GSM-R channel I / Q data are resampled to obtain multiple GSM-R channel I / Q data with a sampling rate matching the GSM-R symbol rate, including: By using a linear interpolation resampling algorithm, multiple GSM-R channel I / Q data are resampled to obtain multiple GSM-R channel I / Q data with a sampling rate matching the GSM-R symbol rate.

4. The method as described in claim 1, characterized in that, From the resampled GSM-R channel I / Q data, extract the frequency correction channel (FCCH) burst signal, including: Based on the GSM-R frame structure, the starting position of the GSM-R frame in the multiple resampled GSM-R channel I / Q data is located using the sliding window autocorrelation method; Based on the starting position, the resampled GSM-R channel I / Q data are divided into time slots to determine the position of the TS0 time slot in each GSM-R frame; Based on the location of the TS0 time slot, the TS0 time slot signal is extracted from the resampled GSM-R channel I / Q data; Frequency domain analysis is performed on the TS0 time slot signal to select TS0 time slot signals whose spectral characteristics conform to FCCH characteristics as FCCH burst signals.

5. The method as described in claim 1, characterized in that, Extract the phase sequence of the FCCH burst signal, perform differential processing on the phase sequence to obtain a phase difference sequence, including: Extract the phase sequence of the FCCH burst signal; The phase sequence is unwound to obtain an unwound phase sequence; The unwound phase sequence is differentially processed to obtain a phase difference sequence.

6. The method as described in claim 1, characterized in that, The frequency domain peak distribution characteristics of the phase difference spectrum are compared and analyzed with the preset multipath interference frequency domain characteristics to obtain the GSM-R multipath interference detection results, including: Extract the amplitude spectrum of the phase difference spectrum to obtain the phase difference amplitude spectrum; Noise floor analysis is performed on the phase difference amplitude spectrum to obtain the noise floor of the phase difference amplitude spectrum; Based on the noise floor, frequency domain peak distribution features are extracted from the phase difference amplitude spectrum; The extracted frequency domain peak distribution features are compared and analyzed with the preset multipath interference frequency domain features to obtain the GSM-R multipath interference detection results.

7. The method as described in claim 6, characterized in that, Noise basis analysis is performed on the phase difference amplitude spectrum to obtain the noise basis of the phase difference amplitude spectrum, including: The phase difference amplitude spectrum is normalized to obtain a normalized phase difference amplitude spectrum. Noise basis analysis is performed on the normalized phase difference amplitude spectrum to obtain the noise basis of the normalized phase difference amplitude spectrum.

8. The method as described in claim 1, characterized in that, The frequency domain peak distribution characteristics include: the presence of secondary peaks and the peak-to-sidelobe ratio; The preset multipath interference frequency domain characteristics include: the existence of at least one secondary peak and the peak-to-sidelobe ratio being less than a preset threshold. The frequency domain peak distribution characteristics of the phase difference spectrum are compared and analyzed with the preset multipath interference frequency domain characteristics to obtain the GSM-R multipath interference detection results, including: If a secondary peak exists in the phase difference spectrum and the peak-to-sidelobe ratio is less than the preset power threshold, then the GSM-R multipath interference detection result indicates the presence of multipath interference.

9. The method as described in claim 8, characterized in that, The frequency domain peak distribution characteristics also include: the number of secondary peaks and the frequency domain spacing of spectral peaks; After the GSM-R multipath interference detection result indicates the presence of multipath interference, it also includes: The intensity level of GSM-R multipath interference is determined based on the number of secondary peaks and the frequency domain spacing of the spectral peaks; among them, the number of secondary peaks is positively correlated with the intensity of GSM-R multipath interference, and the frequency domain spacing of the spectral peaks is also positively correlated with the intensity of GSM-R multipath interference.

10. A GSM-R multipath interference detection device, characterized in that, include: The GSM-R channel extraction module is used to: perform channelization processing on broadband in-phase quadrature I / Q data collected from along the railway line to obtain multiple GSM-R channel I / Q data; The sampling rate calibration module is used to: resample multiple GSM-R channel I / Q data to obtain multiple GSM-R channel I / Q data with a sampling rate that matches the GSM-R symbol rate; The FCCH signal extraction module is used to extract the frequency correction channel FCCH burst signal from multiple resampled GSM-R channel I / Q data. The phase difference calculation module is used to: extract the phase sequence of the FCCH burst signal, perform differential processing on the phase sequence, and obtain a phase difference sequence; The phase difference spectrum calculation module is used to: perform frequency domain transformation on the phase difference sequence to obtain the phase difference spectrum; The GSM-R multipath interference detection module is used to: compare and analyze the frequency domain peak distribution characteristics of the phase difference spectrum with the preset multipath interference frequency domain characteristics to obtain the GSM-R multipath interference detection results.

11. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method of any one of claims 1 to 9.

12. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method of any one of claims 1 to 9.

13. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the method of any one of claims 1 to 9.

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