Tunnel embedded multi-source global coverage repeater system and method

Abstract

The invention relates to the field of communication technology and tunnel engineering crossing technology, and discloses a tunnel-embedded multi-source global coverage repeater system and method, the system comprises a tunnel-embedded deployment structure and repeater modules, the repeater modules are embedded into a tunnel side wall through the tunnel-embedded deployment structure, and multiple modules form a cascade network through cascade interfaces; the repeater module comprises an unvarnished transmission layer, a collaboration layer and an algorithm layer. The method corresponds to the system. According to the method, excavation-free transformation is achieved through tunnel-embedded deployment, construction is simplified, and deployment convenience is improved; the unvarnished transmission layer amplifies a multi-source signal through radio frequency direct connection, and prevents asynchronous interference in combination with time domain synchronization to guarantee signal integrity; the collaborative layer realizes multi-source on-demand collaborative coverage through frequency band identification, dynamic adjustment of coverage weight and transmitting power and signal coupling isolation combination; the algorithm layer constructs a tunnel topology model, predicts the coverage intensity, automatically optimizes the power, eliminates blind areas and avoids redundancy, thereby providing support for tunnel multi-source global high-quality coverage, and meeting intelligent traffic demands.

Description

Technical Field

[0001] This application relates to the interdisciplinary field of communication technology and tunnel engineering, specifically a tunnel-embedded multi-source full-area coverage repeater system and method. Background Technology

[0002] With the rapid development of transportation infrastructure such as highways and railways, tunnels, as key nodes, play a crucial role in ensuring the integrity and stability of their internal communication coverage for driving safety, emergency communication, and user experience. However, tunnels are long, narrow, and enclosed spaces where electromagnetic wave propagation is easily affected by rock wall obstruction and multipath reflection, resulting in rapid signal attenuation.

[0003] Traditional communication coverage solutions suffer from numerous core technical bottlenecks: Existing repeaters are mostly installed externally or on brackets, which requires excavation or drilling of the tunnel sidewalls. This not only damages the integrity of the tunnel structure but also increases the construction period and cost, making them unsuitable for the complex construction environment of tunnels. When multiple signal sources such as 4G, 5G and CATV need to be covered simultaneously in a tunnel, traditional solutions lack an effective signal synchronization mechanism. Multiple signal sources are prone to asynchronous interference in the time and frequency domains, and the coverage weight of each signal source cannot be dynamically adjusted according to signal strength and user density. This results in insufficient coverage in some areas, forming blind spots, or increased interference in areas where multiple signal sources overlap, affecting communication quality. Traditional solutions have a low degree of integration between tunnel topology and signal propagation characteristics, making it difficult to accurately predict coverage intensity in different areas and achieve dynamic optimization of transmission power. Furthermore, the fiber optic transmission channel lacks a reliable self-healing protection mechanism, and a link failure can easily lead to interruption of multi-source data transmission, further reducing coverage stability.

[0004] The aforementioned problems collectively result in insufficient reliability, economy, and adaptability of multi-source full-area coverage within tunnels, making it difficult to meet the demands of next-generation transportation infrastructure for high-quality communication coverage. There is an urgent need for a technical solution that balances excavation-free deployment, multi-source synchronous collaboration, dynamic coverage optimization, and reliable transmission. Summary of the Invention

[0005] The purpose of this application is to provide a tunnel-embedded multi-source full-area coverage repeater system and method to solve the technical problems mentioned in the background art.

[0006] To achieve the above objectives, this application discloses the following technical solutions: In a first aspect, this application discloses a tunnel-embedded multi-source full-area coverage repeater system, including a tunnel-embedded deployment structure and repeater modules. The repeater modules are embedded in the tunnel sidewall through the tunnel-embedded deployment structure, and multiple repeater modules are connected to form a cascaded network through cascading interfaces. The repeater module includes: The pass-through layer directly amplifies and forwards the received multi-source signals through radio frequency pass-through technology without performing signal demodulation or encoding processing. At the same time, it uses time-domain synchronization technology to synchronize the characteristics of the multi-source signals to achieve consistency of the multi-source signal characteristics. The multi-source signals include 4G, 5G and CATV signals. The coordination layer includes a frequency band identification module, a weight calculation module, a power allocation module, and a signal processing module. The frequency band identification module detects the frequency band type of multi-source signals. The weight calculation module dynamically adjusts the coverage weight of multi-source signals based on signal strength, user density, and interference levels. The power allocation module controls the transmission power of each frequency band based on the adjustment results of the coverage weight. The signal processing module performs coupling processing, isolation processing, and combining transmission processing on multi-frequency band signals. The algorithm layer includes a tunnel topology modeling module, a signal strength prediction module, and a power optimization module. The tunnel topology modeling module is used to construct a tunnel topology model of the tunnel geometry and signal propagation. The signal strength prediction module is used to analyze the signal data exchanged between adjacent repeater nodes via RS485 or long-distance radio technology to predict the signal coverage strength of each area. The power optimization module is used to automatically adjust the transmission power based on the signal coverage strength prediction results.

[0007] Preferably, the transparent layer includes a signal receiving module, a wideband filtering module, a synchronization processing module, a delay adjustment module, and a radio frequency pass-through amplification module; The signal receiving module is used to capture multi-source signals through a wideband antenna array and convert them into initial multi-source radio frequency electrical signals; The wideband filtering module is used to filter out the target frequency band components in the received initial multi-source radio frequency signal, remove interference signals from non-target frequency bands, and retain the pure multi-source signal. The synchronization processing module is used to extract synchronization identifiers from reference signals or clean multi-source signals sent by the base station, construct a unified time-domain reference frame, compare the time-domain characteristics of each clean multi-source signal with the time-domain reference frame, and calculate the time-domain deviation data of each signal. The delay adjustment module is used to adjust the delay duration of the signal transmission path according to the time domain deviation data output by the synchronization processing module, so that the phase difference of all pure multi-source signals in the time domain is controlled within a preset range, and a synchronized multi-source signal is obtained. The radio frequency pass-through amplification module is used to directly amplify the synchronized multi-source signal without signal demodulation or encoding processing to maintain the original modulation mode and encoding structure of the signal, and then transmit the amplified multi-source signal to the coordination layer.

[0008] Preferably, the synchronization processing module includes a feature extraction unit and a deviation calculation unit; The feature extraction unit is used to analyze the time-domain feature parameters of the pure multi-source signal and transmit the time-domain feature parameters to the deviation calculation unit; The deviation calculation unit is used to compare the time-domain characteristic parameters of each pure multi-source signal with the standard parameters within the frame one by one, based on the constructed time-domain reference frame, and calculate the time delay value and phase offset of each signal. The delay adjustment module includes a programmable delay unit and a phase calibration unit; The programmable delay unit is used to compensate for the delay of the transmission path of the corresponding pure multi-source signal based on the time delay value. At the same time, the phase calibration unit corrects the phase deviation of the signal by adjusting the phase compensation device of the signal transmission circuit according to the phase offset. During the delay compensation and phase deviation correction process, the deviation calculation unit collects the adjusted signal characteristics in real time and compares them with the time domain reference frame. If the deviation of a certain signal still exceeds the preset range, a recalibration command is sent to the delay adjustment module until the time domain characteristics of all pure multi-source signals are consistent with the reference frame, forming a synchronized multi-source signal.

[0009] Preferably, the method of dynamically adjusting the coverage weight of multi-source signals based on signal strength, user density, and interference level includes: Real-time signal strength data of each frequency band, user density data of each area in the tunnel, and interference level data between each frequency band are collected from multi-source signals. Based on the collected data, the coverage weight of each frequency band is dynamically adjusted according to the principles of prioritizing the increase of the corresponding frequency band weight in areas with insufficient signal strength, adapting high-weight signals to areas with high user density, and reducing the weight of frequency bands with severe interference. Finally, the weight allocation results of each frequency band are output.

[0010] Preferably, the control of the transmission power of signals in each frequency band based on the coverage weight result output by the weight calculation module includes: The power allocation module converts the coverage weight of each frequency band into a corresponding power allocation ratio and divides the total transmit power resources of the system. For frequency band signals with high weighting, more power resources are allocated to enhance their coverage. For frequency band signals with low weighting, appropriate base power is allocated to meet basic coverage requirements. At the same time, the power allocation module monitors the actual transmit power data of each frequency band signal in real time and compares the monitored data with the allocated power ratio. If a deviation occurs, the power amplification link of the corresponding frequency band is adjusted.

[0011] Preferably, the process of constructing the tunnel topology model includes: The tunnel topology modeling module acquires the original geometric structure data and signal propagation characteristic data of the tunnel; The acquired raw data is preprocessed to remove measurement errors in the geometric structure data and correct for environmental interference in the signal propagation characteristic data. A three-dimensional mesh model of the tunnel is constructed based on the preprocessed geometric data, and the installation positions of curves, obstacles and repeater modules in the tunnel are marked. Based on the preprocessed signal propagation characteristic data, different regions are assigned corresponding attenuation coefficients and reflection coefficients in the tunnel three-dimensional mesh model to form a tunnel topology model with signal propagation laws.

[0012] Preferably, the prediction of signal coverage strength in each region includes: The signal strength prediction module receives exchange data sent by adjacent repeater modules, parses the exchange data, and extracts the current signal strength value, transmit power value, and installation location coordinates of each adjacent repeater module. The parsed information of adjacent repeater modules is input into the tunnel topology model to determine the coverage boundaries of each adjacent repeater module and the relative positional relationship between the area to be predicted and each adjacent repeater module. Based on the signal propagation characteristic parameters of the area to be predicted in the tunnel topology model, and according to the transmission power and relative position of the adjacent repeater modules, the propagation loss of the signal from the adjacent repeater modules to the area to be predicted is calculated by the signal propagation prediction algorithm. Based on the current signal strength values ​​of adjacent repeater modules and the calculated propagation loss, the predicted signal coverage strength value of the area to be predicted is obtained, and areas with predicted values ​​lower than the preset blind zone determination threshold are marked as potential coverage blind zones.

[0013] Preferably, the automatic adjustment of the transmission power based on the signal coverage strength prediction result includes: The power optimization module receives the predicted coverage strength values ​​for each area and the markers of potential coverage blind spots output by the signal strength prediction module; it then classifies and judges the prediction results: if the predicted coverage strength of a certain area is higher than the preset blind spot determination threshold and there is no risk of overlapping interference, the current transmission power is maintained; if a certain area is a potential coverage blind spot, the transmission power of the corresponding repeater module needs to be increased; if the predicted coverage strength values ​​of areas where the coverage ranges of two or more repeater modules overlap exceed the preset overlap anti-interference threshold, the transmission power of at least one repeater module needs to be reduced to avoid interference. For situations requiring power adjustment, the required power adjustment range is calculated based on the difference between the predicted coverage intensity value of each area and the corresponding preset blind zone determination threshold, as well as the signal propagation loss coefficient of the tunnel in that area. The power optimization module sends a power adjustment command to the corresponding repeater module, and the repeater module responds to the power adjustment command and controls the built-in power amplifier circuit to change the output power. After the power adjustment is completed, the power optimization module obtains the adjusted area coverage intensity prediction value through the signal strength prediction module, and repeats the classification judgment to verify the adjustment effect. If there are still cases where the power needs to be adjusted, the adjustment range is repeatedly calculated and executed until the tunnel full coverage meets the standard.

[0014] Preferably, this tunnel-embedded multi-source full-area coverage repeater system also includes a transmission protection mechanism; the transmission protection mechanism includes a link monitoring module, a dual-ring network control module, and an optical fiber self-healing switching module; The link monitoring module is used to collect link status data in real time of each repeater module in the tunnel and the optical fiber transmission channel used to transmit multi-source signals and node interaction data. The collected link status data is compared with a preset normal threshold. If the link status data exceeds the threshold, it is determined to be a link abnormality and an abnormal alarm signal is output. The dual-ring network control module is used to construct a primary and backup dual-ring transmission link, connecting the fiber optic interfaces of all repeater modules in the tunnel to the primary ring link and the backup ring link respectively. The primary ring link is used for daily transmission of multi-source signals of the transparent transmission layer and adjacent node signal data required by the algorithm layer. The backup ring link is used to synchronously transmit key data of the primary ring link. The key data includes the real-time signal strength, current transmission power and link status data of each repeater module. The fiber optic self-healing switching module is used to trigger self-healing protection when the link is abnormal. In response to the abnormal alarm signal, after locating the abnormal link, it starts the self-healing switching logic: if the abnormality occurs in the main ring link, the transmission load of the main ring link is switched to the backup ring link, and the signal input of the main ring link is cut off at the same time; if the backup ring link detects the abnormality at the same time, the dual-ring network control module constructs a temporary transmission path through other normal nodes and performs link switching. After the switchover is completed, the link monitoring module continuously collects the link status data after the switchover to verify whether the transmission has returned to normal. If it has returned to normal, the current link transmission is maintained; if it is still abnormal, the self-healing switchover logic is repeated until the optical fiber transmission channel resumes reliable transmission.

[0015] Secondly, this application discloses a method for use in the tunnel-embedded multi-source full-area coverage repeater system described above, the method comprising: Step 1: Deploy repeater modules. The repeater modules are embedded into the tunnel sidewall using a tunnel-embedded deployment structure, and multiple repeater modules are connected through cascading interfaces to form a cascading network. Step 2: Transmission layer processing, which directly amplifies and forwards the received multi-source signals using radio frequency pass-through technology without signal demodulation or encoding, and simultaneously uses time-domain synchronization technology to synchronize the characteristics of the multi-source signals to achieve consistency of the multi-source signal characteristics; wherein, the multi-source signals include 4G, 5G and CATV signals; Step 3: Collaboration layer processing, including: Step 31: Detect the frequency band type of the multi-source signal using the frequency band identification module; Step 32: The coverage weight of the multi-source signals is dynamically adjusted based on signal strength, user density, and interference level using the weight calculation module; Step 33: Control the transmit power of each frequency band based on the adjustment results of the coverage weight through the power allocation module; Step 34: The signal processing module performs coupling processing on multi-band signals, isolation processing on signals of different frequency bands, and combining and transmission processing on multi-band signals. Step 4: Algorithm layer processing, including: Step 41: Construct a tunnel topology model that includes the tunnel geometry and signal propagation characteristics using the tunnel topology modeling module; Step 42: Analyze the signal data exchanged between adjacent repeater nodes via RS485 or long-distance radio technology using the signal strength prediction module to predict the signal coverage strength of each area; Step 43: The power optimization module automatically adjusts the transmission power based on the signal coverage strength prediction results; Step 5: Transmission protection processing. Through link monitoring, dual-ring network control and fiber optic self-healing switching mechanism, the status of the fiber optic transmission channel connecting each repeater module is monitored and anomalies are handled to ensure reliable transmission of multi-source signals and node interaction data.

[0016] Beneficial Effects: The tunnel-embedded multi-source full-coverage repeater system and method of this application embeds the repeater module into the tunnel sidewall through a tunnel-embedded deployment structure, eliminating the need for excavation or drilling modifications to the tunnel lining structure. This avoids the damage to the tunnel structural integrity caused by traditional external deployments and is adaptable to the special working conditions of dampness, dust, fire prevention, and explosion protection within tunnels. It also simplifies the construction process and improves the environmental adaptability and ease of implementation of the system deployment. Through the radio frequency direct pass-through technology and time-domain synchronization technology of the pass-through layer, the received multi-source signals are directly amplified and forwarded, and the signal characteristics are synchronized, effectively avoiding interference problems caused by asynchronous time-domain and frequency-domain characteristics of multiple sources, ensuring signal integrity during multi-source transmission. Through the collaborative work of the frequency band identification module, weight calculation module, power allocation module, and signal processing module, the frequency band types of multi-source signals are first accurately distinguished, and then the power allocation is dynamically adjusted according to the actual signal strength, user density, and interference level. The system integrates coverage weight and transmission power, ultimately coupling, isolating, and combining multi-band signals to achieve on-demand adaptation and efficient collaborative coverage of multiple signal sources within the tunnel. A tunnel topology model constructed by the tunnel topology modeling module, combined with the signal strength prediction module's analysis of interaction data between adjacent repeater nodes, accurately predicts the signal coverage in various tunnel areas. The power optimization module then automatically adjusts the transmission power based on the prediction results, effectively eliminating coverage blind spots common in traditional solutions and avoiding power redundancy in overlapping areas of multiple modules, ensuring stable full-area coverage of multiple signal sources within the tunnel. Furthermore, a cascaded network is formed by connecting multiple repeater modules through cascade interfaces, allowing for flexible expansion of the coverage range based on the actual tunnel length, adapting to the communication coverage needs of tunnels of different sizes. Ultimately, this provides reliable technical support for high-quality full-area coverage of multiple service signal sources in tunnel scenarios, meeting the core requirements of intelligent transportation for tunnel communication. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a structural block diagram of a tunnel-embedded multi-source full-area coverage repeater system provided in an embodiment of this application. Detailed Implementation

[0019] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0020] In this document, the term "comprising" is intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0021] This embodiment aims to address the core problems of traditional tunnel multi-source coverage schemes, such as the need to disrupt the tunnel structure for repeater deployment, the susceptibility to interference due to asynchronous time-frequency characteristics of multiple sources, insufficient accuracy in coverage intensity prediction and power adjustment, and the difficulty in rapid self-healing after fiber optic transmission link failures. In the first aspect, it provides a solution... Figure 1 The tunnel-embedded multi-source full-area coverage repeater system shown includes a tunnel-embedded deployment structure and repeater modules. The repeater modules are embedded in the tunnel sidewall through the tunnel-embedded deployment structure, and multiple repeater modules are connected to form a cascaded network through cascade interfaces.

[0022] The tunnel-embedded deployment structure can be any existing installation structure that can be embedded into the tunnel sidewall, such as the existing elastic snap-fit ​​installation structure. Its structure includes: an arc-shaped snap-fit ​​base that matches the tunnel sidewall; an adjustable-angle fixing bracket; and a self-locking device to ensure stable installation in the high-humidity environment of the tunnel. The elastic snap-fit ​​uses PA66+30% glass fiber composite material commonly used in engineering fields, adapting to the common concrete or brick surface curvature of tunnel sidewalls. No drilling is required during installation; the snap-fit ​​is fixed by elastically deforming and snapping into a pre-set shallow groove (depth ≤20mm) in the tunnel sidewall. Secondly, the cascade interface adopts a dual-mode interface compatible with RS485 and LoRa, allowing selection of the transmission method based on the tunnel length (LoRa for short distances ≤500m, RS485 for long distances >500m).

[0023] To clarify the matching relationship between the number of modules in the cascaded network and the tunnel coverage requirements, the following formula for calculating the minimum deployment number of repeater modules is used to ensure full coverage without blind spots: In the formula, Minimum number of repeater modules to be deployed in the tunnel (rounded up); Total tunnel length (unit: m), taken from tunnel construction design drawings; Effective coverage radius of a single direct current station module (unit: m), obtained through field testing (e.g., 4G / 5G signal coverage in a concrete tunnel). m, CATV signal m); Maximum deflection angle of tunnel curves (unit: rad), taken from tunnel geometry data collected by laser scanning equipment, for straight tunnels. ( ), curve tunnel Calculated based on the actual curvature (e.g., a curve with a curvature radius of 500m). rad, This formula allows for the precise calculation of the minimum number of modules required for tunnels of different lengths and curvatures. This avoids cost waste caused by module redundancy and prevents coverage blind spots caused by insufficient modules, providing a quantitative basis for system deployment. Combined with the tunnel-embedded deployment structure and dual-mode cascade interface, it enables flexible adaptation to tunnels of different sizes.

[0024] Specifically, the repeater module includes: Component 1, the pass-through layer, directly amplifies and forwards received multi-source signals using radio frequency pass-through technology without demodulation or encoding. Simultaneously, time-domain synchronization technology synchronizes the characteristics of the multi-source signals to achieve consistency. These multi-source signals include 4G (fourth-generation mobile communication technology), 5G (fifth-generation mobile communication technology), and CATV (Cable Television) signals. Feasibly, the radio frequency pass-through technology employs a GaN-based broadband power amplifier, supporting unified amplification across the 4G (1.8GHz), 5G (3.5GHz), and CATV (750MHz) frequency bands. Secondly, the time-domain synchronization technology uses the synchronization signal block (SSB) issued by the 5G base station as a reference, automatically switching to the 4G primary synchronization signal (PSS) when no 5G signal is available, ensuring a unified synchronization benchmark for the multiple signal sources.

[0025] Component 2, the Collaboration Layer, includes a frequency band identification module, a weight calculation module, a power allocation module, and a signal processing module. The frequency band identification module detects the frequency band type of multi-source signals. The weight calculation module dynamically adjusts the coverage weight of multi-source signals based on signal strength, user density, and interference levels. The power allocation module controls the transmission power of each frequency band based on the adjustment results of the coverage weights. The signal processing module performs coupling processing, isolation processing, and combining transmission processing of multi-frequency band signals. Component 3, the algorithm layer, includes a tunnel topology modeling module, a signal strength prediction module, and a power optimization module. The tunnel topology modeling module is used to construct a tunnel topology model of the tunnel geometry and signal propagation. The signal strength prediction module is used to analyze the signal data exchanged between adjacent repeater nodes via RS485 (Recommended Standard 485) or LoRa (Long Range) technology to predict the signal coverage strength of each area. The power optimization module is used to automatically adjust the transmission power based on the signal coverage strength prediction results.

[0026] Based on the above, the tunnel-embedded multi-source full-area coverage repeater system of this embodiment solves the problems of traditional repeaters damaging the tunnel structure and having poor deployment flexibility through the tunnel-embedded deployment structure and dual-mode cascade interface, adapting to the coverage requirements of tunnels of different lengths; through radio frequency direct pass and unified reference time domain synchronization technology, it avoids the delay and asynchronous interference caused by multi-source demodulation coding, ensuring the integrity and consistency of multi-source signal transmission; through the module division of labor of the coordination layer and algorithm layer, it realizes the full-process control of multi-sources from type identification, weight adaptation to coverage optimization, providing system-level support for tunnel multi-source full-area coverage.

[0027] In this embodiment, the transparent transmission layer includes a signal receiving module, a wideband filtering module, a synchronization processing module, a delay adjustment module, and a radio frequency pass-through amplification module.

[0028] The signal receiving module is used to capture multi-source signals through a broadband antenna array and convert them into initial multi-source radio frequency electrical signals. Feasibly, the broadband antenna array adopts an industry-standard 4-element microstrip antenna structure, with the element spacing based on the CATV signal wavelength (wavelength corresponding to 750MHz). The design is half of the m), with an antenna gain of ≥8dBi, which can simultaneously capture 4G (1.8GHz), 5G (3.5GHz), and CATV (750MHz) signals and convert them into initial RF electrical signals of -30~-10dBm, thus meeting the conventional input range of RF signal processing.

[0029] The wideband filtering module is used to filter out the target frequency band components in the received initial multi-source radio frequency signals, remove interference signals from non-target frequency bands, and retain the pure multi-source signals. Feasibly, the wideband filtering module adopts an industry-known multi-band bandpass filter, integrating three independent filtering channels (4G channel: 1.71~1.88GHz, 5G channel: 3.4~3.6GHz, CATV channel: 700~800MHz). This filter has an out-of-band rejection of ≥40dB and an insertion loss of ≤1dB, effectively filtering out interference signals from adjacent frequency bands (such as interference from 1.9GHz LTE signals to the 4G channel), which is a conventional filtering scheme in radio frequency signal processing.

[0030] The synchronization processing module is used to extract synchronization identifiers (such as the frame synchronization header of 4G / 5G signals and the synchronization byte of CATV signals) from the reference signal or clean multi-source signal sent by the base station, construct a unified time-domain reference frame, and compare the time-domain characteristics of each clean multi-source signal with the time-domain reference frame to calculate the time-domain deviation data of each signal. Feasibly, the synchronization identifiers are selected from signal characteristics defined in industry standards, specifically: the primary synchronization signal (PSS) and secondary synchronization signal (SSS) of 4G signals, the synchronization signal block (SSB) of 5G signals, and the synchronization byte (0x47) of CATV signals; the time-domain reference frame is based on the period (10ms) of the 5GSSB, with time accuracy controlled within ±1μs, meeting the signal synchronization accuracy requirements in the 3GPP standard.

[0031] The delay adjustment module is used to adjust the delay duration of the signal transmission path based on the time-domain deviation data output by the synchronization processing module, so that the phase difference of all pure multi-source signals in the time domain is controlled within a preset range, thus obtaining synchronized multi-source signals. Feasibly, the delay adjustment module uses an industry-known programmable delay line (such as AD9508), with a delay adjustment accuracy of 1ns and a preset multi-source signal phase difference range ≤5°; the RF pass-through amplification module uses a commonly used GaN-based wideband power amplifier (operating frequency band 0.7~3.6GHz), with a gain adjustment range of 20~30dB and an output power ≤10W. The amplified signal is directly transmitted to the frequency band identification module of the coordination layer, ensuring that the original modulation method and coding structure are not changed during signal transmission.

[0032] The RF pass-through amplification module is used to directly amplify synchronized multi-source signals without signal demodulation or encoding processing to maintain the original modulation scheme and encoding structure, and then transmit the amplified multi-source signals to the coordination layer. Feasibly, the wideband RF amplification link can be any existing technology, and the gain of the RF pass-through amplification link can be controlled by an MCU, with a gain adjustment range of 20-30dB, ensuring that the power of amplified signals from different frequency bands matches the requirements of the coordination layer.

[0033] Based on the above, the tunnel-embedded multi-source full-coverage repeater system of this embodiment improves the acquisition strength and purity of the initial signal and reduces the interference basis for subsequent synchronization processing by using a multi-element wideband antenna and a multi-band bandpass filter with high out-of-band suppression. By using a time-domain reference frame with μs-level precision and ns-level delay adjustment, the phase difference of the multiple sources is controlled within a very small range to avoid signal distortion caused by time-domain asynchrony. By using a wideband GaN power amplifier, the system adapts to the power requirements of the coordination layer while maintaining the original signal structure, providing high-quality signal input for multi-source collaborative processing.

[0034] Furthermore, the synchronization processing module includes a feature extraction unit and a deviation calculation unit.

[0035] The feature extraction unit is used to analyze the time-domain feature parameters of the clean multi-source signal and transmit the time-domain feature parameters to the deviation calculation unit. Feasibly, the time-domain feature parameters analyzed by the feature extraction unit include: frame synchronization header position (accuracy ±0.1μs) and symbol period (4G symbol period 16.67μs, 5G symbol period 33.33μs) for 4G and 5G signals, and synchronization byte interval (204μs) and clock frequency (25MHz) for CATV signals.

[0036] The deviation calculation unit is used to compare the time-domain characteristic parameters of each pure multi-source signal with the standard parameters within the established time-domain reference frame, and calculate the time delay value and phase offset (i.e., the difference between the signal phase and the standard phase) of each signal. Feasibly, to avoid the impact of single feature point errors on synchronization accuracy, this embodiment calculates the time delay value using the following formula: In the formula, Time delay value (in μs) of the i-th signal source (i=1 represents 4G, i=2 represents 5G, i=3 represents CATV). : Period of the time-domain reference frame (10 4 μs, which is the period of 5GSSB (10ms). : The actual time (unit: μs) of the kth synchronization feature point of the i-th source, taken from data acquired by a high-speed ADC (sampling rate 100MSPS); : The standard time of the kth synchronization feature point (unit: μs), from industry specifications (4G follows 3GPP TS36.211, 5G follows 3GPP TS38.211, CATV follows GB / T14947). The weight of the kth synchronization feature point (the weight of the 5GSSB) 4GPSS weights Weight of CATV synchronization bytes ), set according to the communication priority of the information source; n: the number of synchronization feature points (4G and 5G signals take n=3, including PSS / SSS / frame header; CATV signals take n=2, including synchronization byte / clock mark).

[0037] Secondly, the formula for calculating the phase offset is as follows: In the formula, Phase offset of the i-th source (unit: rad); The actual phase of the i-th signal source (unit: rad) is obtained through a known quadrature demodulation circuit; The reference phase of the time-domain reference frame (unit: rad) is selected as the carrier phase of the 5GSSB. The carrier frequency of the i-th signal source (unit: Hz, 1.8 × 10⁻⁶ for 4G). 9 5G is 3.5×10 9 CATV is 7.5×10 8 ).

[0038] The delay adjustment module includes a programmable delay unit and a phase calibration unit.

[0039] The programmable delay unit is used to perform delay compensation (e.g., nanosecond-level precision) on the transmission path of the corresponding pure multi-source signal based on the time delay value. Simultaneously, the phase calibration unit corrects the phase deviation of the signal by adjusting the phase compensation devices (e.g., capacitors or inductors) in the signal transmission circuit according to the phase offset. During delay compensation and phase deviation correction, the deviation calculation unit collects the adjusted signal characteristics in real time and compares them twice with the time-domain reference frame. If the deviation of a signal still exceeds a preset range, a recalibration command is sent to the delay adjustment module until the time-domain characteristics of all pure multi-source signals are consistent with the reference frame, forming synchronized multi-source signals.

[0040] Feasible options are to use signal transmission circuits that specifically refer to independent radio frequency transmission branches for 4G, 5G, and CATV signals (each signal source corresponds to one branch, which is a well-known radio frequency circuit design). The phase compensation devices use industry-known variable capacitors (capacitance range 0~10pF) and adjustable inductors (inductance range 10~100nH). The capacitance or inductance value is adjusted by a control voltage of 0~3.3V output by the MCU, and the phase correction accuracy is ≤1°.

[0041] In addition, the preset ranges for the second comparison include: time delay deviation ≤ 10ns and phase offset deviation ≤ 3°. If the range is exceeded, recalibration is triggered to ensure that the final time domain characteristics of the multi-source are consistent with the reference frame.

[0042] Based on the above, the tunnel-embedded multi-source full-coverage repeater system of this embodiment accurately calculates the time-domain deviation of multiple sources by calculating the time delay value and phase offset, avoiding synchronization deviation caused by single feature point error and carrier frequency difference; through a clear RF transmission branch and a known phase compensation device, it ensures that the phase correction scheme can be implemented; through a closed-loop calibration mechanism of secondary comparison, the time-domain synchronization accuracy of multiple sources is controlled within 10ns, completely eliminating asynchronous interference of multiple sources and ensuring the integrity of the signal after RF pass-through amplification.

[0043] In this embodiment, the frequency band identification module detects the frequency band type of the received multi-source signals. The specific processing procedure is as follows: the frequency band identification module extracts the frequency band feature parameters (including signal center frequency, bandwidth, and frequency band identification information) of each signal, compares the extracted feature parameters with a preset standard frequency band database (storing standard features of 4G, 5G, and CATV frequency bands), and determines the specific frequency band type corresponding to each signal. The function of the frequency band type detection is to provide a basis for frequency band differentiation for the coverage weight adjustment of the weight calculation module, the transmit power control of the power allocation module, and the frequency band isolation processing of the signal isolation module, so as to avoid confusion processing of signals of different frequency bands.

[0044] Furthermore, the method of dynamically adjusting the coverage weight of multi-source signals based on signal strength, user density, and interference level includes: Real-time signal strength data of each frequency band was collected from multi-source signals (i.e., multi-source signals after synchronization output from the pass-through layer, collected through a known RSSI detection circuit, sampling frequency 1Hz, detection accuracy ±1dBm, meeting the conventional accuracy requirements for radio frequency signal strength detection), and user density data of each area in the tunnel were collected (from the user perception unit of the system's supporting monitoring layer, which counts the number of terminals in a 50m×50m area in the tunnel by detecting the random access channel (RACH) signal of the terminal (4G, 5G terminals) or the access signal of the CATV user set-top box (unit: people / 100m)). 2 (This refers to a well-known user density detection scheme), and the interference level data between signals in each frequency band (taken from the interference detection unit built into the coordination layer, which uses a well-known real-time spectrum analyzer (resolution bandwidth 10kHz) to detect the mutual interference signal power between frequency bands (unit: dBm), which can accurately identify the interference situation of adjacent frequency bands). Based on the collected data, the coverage weight of each frequency band is dynamically adjusted according to the principles of prioritizing the increase of corresponding frequency band weight in areas with insufficient signal strength, adapting high-weight signals to areas with high user density, and reducing the weight of frequency bands with severe interference. Finally, the weight allocation results of each frequency band are output to provide a basis for the power allocation module to adapt to the signal coverage needs of different areas in the tunnel.

[0045] Feasiblely, to achieve dynamic adaptation of multiple factors, this embodiment calculates the coverage weight using the following formula: Constraints: (in , , The system was optimized and tested across 10 tunnel scenarios (highway, railway, and tunnels of varying lengths), and it meets the priority requirements for multi-source coverage in tunnels.

[0046] In the formula, Coverage weight of the i-th source (range of values) ); Real-time RSSI value of the i-th source (unit: dBm). The maximum RSSI value among all sources; User density in the coverage area of ​​the i-th source (unit: people / 100m) 2 ), The maximum user density inside the tunnel (the actual peak user density measured). Interference power received by the i-th source (unit: dBm); Interference power threshold (unit: dBm), set to -90dBm, based on the terminal anti-interference capability requirements in 3GPP TS38.101-1.

[0047] Secondly, an example of weight adjustment logic: If the RSSI value of a 4G signal is -95dBm ( dBm), with a user density of 6 people / 100m in the coverage area. 2 ( person / 100m 2 The interference power is -95dBm. (dBm), then the coverage weight of the 4G signal. Prioritize and increase the weight of coverage to meet the coverage requirements of areas with weak signals and high density.

[0048] Based on the above, the tunnel-embedded multi-source full-area coverage repeater system of this embodiment ensures the authenticity and reliability of the input data for weight adjustment through known acquisition equipment and circuits, avoiding weight allocation deviations caused by data acquisition errors; by calculating coverage weights through multi-factor weights, it achieves dynamic adaptation of prioritizing coverage in weak signal areas, focusing on protecting high user density areas, and avoiding areas with severe interference, avoiding resource misallocation caused by traditional fixed weights; through quantitative adjustment logic, the weight allocation results are calculable and verifiable, providing an accurate basis for subsequent power allocation.

[0049] Furthermore, the control of the transmission power of signals in each frequency band based on the coverage weight result output by the weight calculation module includes: The power allocation module converts the coverage weight of each frequency band into a corresponding power allocation ratio and divides the total transmit power resources of the system. For frequency band signals with high weighting, more power resources are allocated to enhance their coverage capabilities. For frequency band signals with low weighting, appropriate base power is allocated to meet basic coverage requirements. At the same time, the power allocation module monitors the actual transmit power data of each frequency band signal in real time and compares the monitored data with the allocated power ratio. If a deviation occurs, the power amplification link of the corresponding frequency band is adjusted to ensure that the actual transmit power of each frequency band signal matches the coverage weight, avoiding coverage blind spots or interference due to power imbalance.

[0050] The signal processing module is used for coupling, isolating, and combining multi-band signals. Specifically, the process is as follows: First, the signal coupler couples the synchronous multi-source signals output from the pass-through layer, coupling each frequency band signal to a unified signal transmission channel, providing conditions for subsequent centralized processing. Next, the signal isolation module isolates the coupled multi-band signals, using a frequency isolation circuit to block mutual interference between different frequency band signals based on their frequency differences, ensuring that the signal characteristics of 4G, 5G, and CATV signals are not confused or attenuated during transmission. Finally, the multi-band combining module combines the isolated multi-band signals, integrating them into a single composite signal, which is then transmitted to the tunnel coverage area via a leaky coaxial cable (leaky cable) or wall-mounted antenna, achieving synchronous full-area coverage of multi-band signals.

[0051] In this embodiment, to ensure the basic coverage requirements of low-weight sources, the power allocation is calculated using the following formula: In the formula, : Distributed power of the i-th source (unit: W); The base power of the i-th signal source (unit: W) is 1W for 4G and 5G signals and 0.5W for CATV signals. These are the measured minimum values ​​that meet the basic coverage requirements. The total system transmit power (in W) is set to 10W, based on the tunnel power supply capacity and the known GaN power amplifier hardware parameters (maximum output power 10W). : Coverage weight of the i-th source.

[0052] Secondly, the actual transmit power is monitored using a known power sensor (such as AD8361) with a monitoring accuracy of ±0.5dB and a sampling frequency of 2Hz. The power amplification links for the corresponding frequency bands specifically refer to the independent power amplification links for 4G, 5G, and CATV signals (each link includes a known variable gain amplifier (VGA) and a GaN power amplifier). When the deviation between the actual power and the allocated power is ≥1dB, the gain of the VGA is controlled by the MCU (adjustment range 0~20dB) for correction, with a response time ≤100ms, meeting the real-time requirements of power adjustment.

[0053] Based on the above, the tunnel-embedded multi-source full-area coverage repeater system of this embodiment ensures that low-weight sources (such as CATV) do not interrupt basic coverage through a power allocation formula, while enabling high-weight sources to obtain sufficient power to enhance coverage. It also ensures that the power monitoring and adjustment scheme is feasible through known power sensors and power amplification links, avoiding implementation difficulties caused by complex hardware solutions. Furthermore, it ensures that the actual transmit power of each frequency band matches the allocation ratio through real-time monitoring and rapid adjustment, avoiding insufficient coverage or interference superposition caused by power deviations, and improving power utilization efficiency.

[0054] In this embodiment, the process of constructing the tunnel topology model includes: The tunnel topology modeling module acquires the original geometric structure data of the tunnel (such as imported data from tunnel construction drawings (including length, curve location, and cross-sectional dimensions) or collected on-site by laser scanning equipment (supplementing the distribution of obstacles not marked on the drawings)) and the original signal propagation characteristics data (such as propagation loss data, reflection coefficient data, and multipath propagation parameters collected by a signal testing instrument at different locations in the tunnel (such as curves, straight sections, and near obstacles). The acquired raw data is preprocessed to remove measurement errors in the geometric structure data (such as eliminating cross-sectional dimension data that are outside the reasonable range) and to correct environmental interference in the signal propagation characteristic data (such as eliminating abnormal attenuation data caused by temporary obstruction). A three-dimensional mesh model of the tunnel is constructed based on the preprocessed geometric data, and the installation positions of curves, obstacles and repeater modules in the tunnel are marked. Based on the preprocessed signal propagation characteristic data, different regions are assigned corresponding attenuation coefficients and reflection coefficients in the tunnel three-dimensional mesh model to form a tunnel topology model with signal propagation laws, which is used for subsequent signal strength prediction.

[0055] Feasible methods for obtaining geometric structure data include: 1) importing CAD drawings from the tunnel construction design to obtain tunnel length, curve locations, and cross-sectional dimensions (width × height); 2) using a known 3D laser scanner (such as FaroFocus S70) to collect data on-site, obtaining the morphology of the tunnel wall and the coordinates of obstacles (such as ventilation ducts), with a scanning accuracy of ±2mm, meeting the accuracy requirements for tunnel geometric data acquisition. Signal propagation characteristic data is obtained using a known vector network analyzer (such as Keysight N9918A) at 20m intervals within the tunnel, collecting signal attenuation data (unit: dB / m), reflection coefficient (dimensionless), and multipath propagation parameters (unit: μs) at each test point. Three sets of data are collected for each test point, and the average value is taken to reduce random errors.

[0056] Secondly, in this embodiment, the industry-known 3σ criterion is used to remove outliers from the original data, as shown in the following formula: In the formula, Valid data after preprocessing; Raw collected data; The mean of the original data; Standard deviation of the original data (calculated from the sample variance).

[0057] Application example: If the signal attenuation data at a certain test point is 2.5 dB / m, while the average value of the data in that area is... dB / m, standard deviation dB / m ( If the value is 2.5 dB / m, it is outside the range and is considered an outlier (possibly due to temporary occlusion) and is removed to ensure data accuracy.

[0058] Furthermore, the 3D mesh model of the tunnel was constructed using the well-known AutoCAD Civil 3D software, with the mesh cell size set to 1m×1m×1m (balancing model accuracy and computational efficiency). The model was marked with tunnel curves (radius of curvature), obstacles (dimensions and coordinates), and the installation location of the repeater module (2.5m above the ground, consistent with the standard installation height for tunnel equipment). Based on the preprocessed propagation characteristic data, parameters were assigned to different regions of the model: an attenuation coefficient of 0.5dB / m for straight sections, 1.2dB / m for curved sections, a reflection coefficient of 0.8 for concrete walls, and a reflection coefficient of 0.95 for metal obstacles—all measured conventional values ​​in tunnel scenarios.

[0059] Based on the above, the tunnel-embedded multi-source full-area coverage repeater system of this embodiment ensures the accuracy of tunnel geometry and signal propagation characteristics data through known acquisition equipment and methods, avoiding the impact of original data errors on model accuracy; through 3σ criterion preprocessing, outliers are effectively eliminated, ensuring the reliability of the input model data; by constructing a three-dimensional mesh model using known software and assigning regional parameters, the topology model can reflect both the physical structure of the tunnel and the signal propagation law, solving the defect of traditional models that emphasize geometry but neglect propagation, and providing accurate model support for subsequent signal strength prediction.

[0060] Furthermore, the prediction of signal coverage strength in each region includes: The signal strength prediction module receives exchange data sent by adjacent repeater modules, parses the exchange data, and extracts the current signal strength value, transmit power value, and installation location coordinates of each adjacent repeater module. The parsed information of the adjacent repeater modules is input into the tunnel topology model to determine the coverage boundaries of each adjacent repeater module, as well as the relative positional relationship (such as distance and whether there is a curve blockage) between the area to be predicted and each adjacent repeater module. Based on the signal propagation characteristic parameters (attenuation coefficient, reflection coefficient) of the area to be predicted in the tunnel topology model, the propagation loss of the signal from the adjacent repeater module to the area to be predicted is calculated by a signal propagation prediction algorithm (such as ray tracing method) according to the transmission power and relative position of the adjacent repeater module. Based on the current signal strength values ​​of adjacent repeater modules and the calculated propagation loss, the predicted signal coverage strength value of the area to be predicted is obtained, and areas with predicted values ​​lower than the preset blind zone determination threshold are marked as potential coverage blind zones.

[0061] Feasible approach is to encapsulate the exchanged data using the industry-standard JSON format, including fields such as: module ID (e.g., "Mod_001"), current RSSI value (dBm), transmit power (dBm), and installation coordinates (x, y, z, m, with the tunnel entrance as the origin). The data transmission rate is ≤100kbps, transmitted via RS485 or LoRa links, meeting the bandwidth requirements for inter-module data exchange.

[0062] Secondly, based on the well-known signal propagation attenuation law, the distance to the coverage area boundary is calculated as follows: ,in This refers to the transmit power of the repeater module (unit: dBm). This is the minimum receiving sensitivity of the terminal (-120dBm for 5G terminals, in accordance with 3GPP standards). This represents the signal attenuation coefficient (unit: dB / m, taken from the tunnel topology model) for the region to be predicted. For example, when... dBm, At dB / m m, but in practice, due to hardware limitations, the effective coverage radius of a single module is limited. Choose a 30m radius to ensure controllable coverage.

[0063] In addition, to accurately calculate the loss, the propagation loss is calculated using the following formula: In the formula, Free-space propagation loss (unit: dB), calculated using the well-known Friis formula: (Where d is the transmission distance in km; f is the signal frequency in MHz). Tunnel wall attenuation loss (unit: dB). , ( dB / m is the conventional wall attenuation coefficient for concrete tunnels. Additional losses on curves (unit: dB). ( (This refers to the tunnel curve deflection angle, in rad, taken from the topology model). Multipath propagation loss (unit: dB). Based on the fitting of measured data of multipath propagation in tunnels, it is consistent with the attenuation law of multipath signals in tunnels.

[0064] Furthermore, the signal propagation prediction algorithm employs the industry-renowned ray tracing method, considering the direct, single-reflection, and single-diffraction paths of the signal. The algorithm is implemented using the well-known MATLAB software, achieving a computational efficiency of ≤1s / area, meeting real-time prediction requirements. Additionally, the preset blind zone determination threshold is set to the minimum receiving sensitivity of the 5G terminal minus 120dBm (complying with the 3GPP TS38.101-1 standard). If the predicted signal coverage strength of the area to be predicted is lower than this threshold, it is marked as a potential coverage blind zone.

[0065] Based on the above, the tunnel-embedded multi-source full-area coverage repeater system of this embodiment ensures that the information of adjacent repeater modules can be effectively parsed through the standardized JSON data format, avoiding information loss due to inconsistent data formats; it avoids the prediction error of traditional simplified models (considering only free space loss) by using a multi-factor propagation loss formula, thereby improving the accuracy of coverage intensity prediction; and it accurately locates potential weak coverage areas by using the well-known ray tracing method and a clear blind zone threshold, providing a clear adjustment target for subsequent power optimization.

[0066] Furthermore, the automatic adjustment of the transmission power based on the signal coverage strength prediction result includes: The power optimization module receives the predicted coverage strength values ​​for each area and the markers of potential coverage blind spots output by the signal strength prediction module; it then classifies and judges the prediction results: if the predicted coverage strength of an area is higher than the preset blind spot determination threshold and there is no risk of overlapping interference, the current transmission power is maintained; if an area is a potential coverage blind spot (the predicted value is lower than the preset blind spot determination threshold), the transmission power of the corresponding repeater module needs to be increased; if the predicted coverage strength of an area where the coverage ranges of two or more repeater modules overlap exceeds the preset overlap anti-interference threshold (the highest coverage standard used to avoid co-channel interference, which is set based on the anti-interference capability of the user terminal), the transmission power of at least one repeater module needs to be reduced to avoid interference. The no-overlap interference risk value satisfies any of the following conditions: first, the number of overlapping modules in the coverage area is <2; second, the predicted signal coverage strength of the overlapping area is ≤ the preset overlap anti-interference threshold (-85dBm, set based on the requirements for adjacent channel interference in 3GPP TS38.101-1). For areas where coverage overlaps, since tunnels are long and narrow spaces, adjacent repeater modules need to partially overlap their coverage areas to avoid signal blind spots (e.g., if the installation distance between adjacent modules is 50 meters and the coverage radius of a single module is 30 meters, then the 20-meter area between the two modules is the coverage overlap area). Secondly, the identification of this overlap area includes: ① extracting the installation coordinates and preset coverage radius (set according to the module power) of each repeater module from the tunnel topology model; ② drawing the coverage boundary of each module in the tunnel 3D mesh model with the installation coordinates of each module as the center and the preset coverage radius as the radius; ③ filtering out the mesh areas that are "simultaneously contained by the coverage boundaries of two or more modules", marking them as areas where coverage overlaps, and recording the number of coverage modules corresponding to this area (e.g., 2 overlapping modules, 3 overlapping modules). Furthermore, the criteria for determining whether the predicted coverage strength in overlapping areas exceeds the preset overlap anti-interference threshold and the resulting problems include: ① The power optimization module first presets an overlap anti-interference threshold for the overlapping area. This threshold must be such that exceeding it will result in unstable signal communication and potential additional interference. For example, if the minimum receiving sensitivity of user terminals (such as mobile phones and emergency communication equipment) in the tunnel is -90dBm, then the preset overlap anti-interference threshold is -85dBm (with a 5dBm redundancy). ③ When the predicted coverage strength of the overlapping area output by the signal strength prediction module exceeds this preset overlap anti-interference threshold, it is determined to be "predicted value too high." An excessively high prediction value will cause two core problems: ① Co-channel interference: Signals from multiple modules operating on the same frequency band (such as all being 5G signals) overlap in the overlapping area, leading to signal phase confusion and increased bit error rate when received by user terminals (e.g., call lag, data transmission packet loss); ② Resource waste: Excessive module transmission power consumes more power, and the excess signal strength has no actual communication gain, instead increasing the complexity of the electromagnetic environment in the tunnel.

[0067] For situations requiring power adjustment, the required power adjustment range is calculated based on the difference between the predicted coverage intensity value of each area and the corresponding preset blind zone determination threshold, as well as the signal propagation loss coefficient of the tunnel in that area (e.g., if the predicted blind zone value is 8dB lower than the blind zone determination threshold, and the propagation loss coefficient of that area is 0.8, then the adjustment range is 8dB ÷ 0.8 = 10dB). The power optimization module sends a power adjustment command to the corresponding repeater module, and the repeater module responds to the power adjustment command and controls the built-in power amplifier circuit to change the output power. After the power adjustment is completed, the power optimization module obtains the adjusted area coverage intensity prediction value through the signal strength prediction module, and repeats the classification judgment to verify the adjustment effect. If there are still cases where the power needs to be adjusted, the adjustment range is repeatedly calculated and executed until the tunnel full coverage meets the standard.

[0068] Feasible adjustment procedures for when the predicted coverage strength of overlapping areas exceeds the preset anti-interference threshold include: ① Locating the repeater modules corresponding to the overly high areas: Retrieving the marking information of the overlapping areas from the tunnel topology model to determine which repeater modules jointly cover the area (e.g., overlapping area A is covered by repeater modules 1, 2, and 3); ② Analyzing the coverage contribution of each repeater module: Calculating the signal contribution percentage of each repeater module to the overlapping area using the signal strength prediction module (e.g., repeater module 1 is closest to the overlapping area and contributes 60% of the signal strength; repeater modules 2 and 3 each contribute...). 20%); ③ Formulate differentiated adjustment strategies: Prioritize reducing the transmission power of "high-contribution and non-critical coverage repeater modules". For example, if repeater module 1 has the highest contribution and its individual coverage area has no blind zone risk, then reduce the transmission power of repeater module 1 by 5-8dB; repeater modules 2 and 3, because their coverage areas also include other blind zone edges, only reduce the power by 2-3dB; ④ Verify the adjustment effect: After adjustment, the signal strength prediction module recalculates the coverage strength prediction value of the overlapping area. If the prediction value drops to within the preset overlap anti-interference threshold range, the adjustment is complete; if it is still too high, repeat steps ① to ③ of this process until the prediction value meets the standard, avoiding interference while ensuring no blind zones.

[0069] Secondly, in this embodiment, the power adjustment range is calculated according to the region type (blind zone or overlapping zone) using the following formula: Blind spot adjustment range (power increase required): Overlap area adjustment range (power reduction required): In the formula, dBm (blind zone detection threshold). dBm (overlapping anti-interference threshold); : Predicted signal coverage strength of the area to be adjusted (unit: dBm); : Signal propagation loss coefficient of the area to be adjusted (unit: dB / m, taken from the tunnel topology model). dB (Power adjustment margin, used to cope with environmental fluctuations in the tunnel, is a standard margin setting in the engineering field).

[0070] Furthermore, the corresponding repeater modules specifically refer to all modules covering the area to be adjusted: when adjusting blind zones, the power of all coverage modules is increased; when adjusting overlapping areas, the power of the module that contributes the most to the coverage of that area is preferentially reduced (the contribution is calculated based on the distance between the module and the area and the attenuation coefficient). The power adjustment command adopts a well-known binary format, containing the module ID and target power (unit: dBm) fields, and is transmitted via an RS485 link. The reliability of the command is guaranteed by a well-known CRC check.

[0071] Furthermore, after the power adjustment is completed, the coverage strength prediction value of the area is re-acquired through the signal strength prediction module after 5 seconds, and the classification and judgment process is repeated to verify the effect; until the prediction value of all areas in the tunnel is ≥-120dBm and the prediction value of the overlapping area is ≤-85dBm, it is determined that the full coverage meets the standard.

[0072] Based on the above, the tunnel-embedded multi-source full-area coverage repeater system of this embodiment achieves differentiated power control for areas with different coverage states through clear classification and judgment criteria, ensuring coverage requirements in blind spots while avoiding interference in overlapping areas; through a precise adjustment amplitude formula, combined with propagation loss coefficient and engineering margin, it avoids over-adjustment or under-adjustment of power; through clear adjustment objects and verification loops, a closed-loop optimization mechanism is formed, ultimately eliminating coverage blind spots and controlling interference in overlapping areas, while reducing unnecessary power consumption.

[0073] In this embodiment, the tunnel-embedded multi-source full-area coverage repeater system also includes a transmission protection mechanism; the transmission protection mechanism includes a link monitoring module, a dual-ring network control module, and an optical fiber self-healing switching module; The link monitoring module is used to collect link status data (including optical power, signal transmission bit error rate and delay) of each repeater module in the tunnel and the optical fiber transmission channel used to transmit multi-source signals and node interaction data in real time. The collected link status data is compared with preset normal thresholds (such as normal optical power range of -5dBm to 0dBm, bit error rate ≤10-6, and delay ≤50ms). If the link status data exceeds the threshold, it is determined that the link is abnormal and an abnormal alarm signal is output. The dual-ring network control module is used to construct a primary and backup dual-ring transmission link, connecting the fiber optic interfaces of all repeater modules in the tunnel to the primary ring link and the backup ring link respectively. The primary ring link is used for daily transmission of multi-source signals of the transparent transmission layer and adjacent node signal data required by the algorithm layer. The backup ring link is used to synchronously transmit key data of the primary ring link. The key data includes the real-time signal strength, current transmission power and link status data of each repeater module. The fiber optic self-healing switching module is used to trigger self-healing protection when a link is abnormal. In response to an abnormal alarm signal, after locating the abnormal link (such as excessive optical power attenuation in a segment of the main ring link), it initiates the self-healing switching logic: if the abnormality occurs in the main ring link, the transmission load of the main ring link is switched to the backup ring link, and the signal input of the main ring link is cut off to avoid interference from abnormal signals; if the backup ring link detects an abnormality simultaneously (such as a failure of a common node in the dual rings), the dual-ring network control module constructs a temporary transmission path through other normal nodes and performs link switching. After the switchover is completed, the link monitoring module continuously collects the link status data after the switchover to verify whether the transmission has returned to normal (such as optical power and bit error rate returning to within the threshold). If it has returned to normal, the current link transmission is maintained; if it is still abnormal, the self-healing switchover logic is repeated until the optical fiber transmission channel resumes reliable transmission, ensuring that multi-source signal data and node interaction data are not interrupted, and supporting the stable operation of the pass-through layer, the collaboration layer and the dynamic coverage algorithm module.

[0074] Feasible settings include: optical power: using a known optical power meter (such as the Agilent 8163B) for acquisition, with a monitoring accuracy of 0.1 dBm, and a normal threshold set to -5 to 0 dBm (compliant with the conventional optical power range for single-mode fiber transmission); bit error rate (BER): monitored based on the known principle of a bit error rate tester (BERT), with a normal threshold ≤ 10. -6 (Following the ITU-T G.8261 standard for the bit error rate requirements of optical transmission systems); Transmission delay: The round-trip time is calculated by sending a known test frame (frame interval 1s), with a normal threshold of ≤50ms, meeting the real-time requirements of tunnel communication.

[0075] Secondly, in this embodiment, to avoid misjudgment caused by fluctuations in a single parameter, the anomaly determination index is calculated using the following formula: Constraints: When When this happens, it is determined to be a link anomaly; In the formula, Measured optical power (unit: dBm) dBm, dBm is the normal threshold for optical power; Actual bit error rate This is the normal threshold for the bit error rate; Measured transmission delay (unit: ms) ms is the normal latency threshold.

[0076] In addition, the dual-ring network structure adopts the industry-known two-fiber bidirectional multiplex section shared protection ring (MS-SPRing) structure (compliant with ITU-T G.841 standard). Both the main ring and the backup ring use 2-core single-mode optical fiber (transmission rate 1Gbps), and the optical fiber interface of the repeater module is the industry-common SC / APC type. The key data synchronously transmitted on the backup ring link is transmitted through the well-known time division multiplexing (TDM) method, which does not occupy the main bandwidth of the main ring and ensures the transmission efficiency of the main ring.

[0077] Furthermore, the location of abnormal links is determined using a known node-by-node polling method (sending link detection frames to each module and identifying faulty nodes based on feedback), with a location time of ≤10ms. The self-healing switching logic is implemented using a known FPGA chip, with a switching time of ≤50ms, meeting the self-healing time requirements of the ITU-T G.841 standard. If the backup link synchronization fails, the dual-ring network control module uses a known shortest path first algorithm (calculated based on module installation coordinates) to select other normal nodes to construct a temporary transmission path, ensuring uninterrupted data transmission.

[0078] Based on the above, the tunnel-embedded multi-source full-area coverage repeater system of this embodiment avoids false switching caused by transient fluctuations of a single parameter by using an anomaly judgment index fused with multiple parameters, thereby improving the accuracy of anomaly judgment; it controls the link fault recovery time by using a dual-ring network structure that conforms to international standards and fast self-healing switching, thereby meeting the reliability requirements of tunnel communication; and it copes with extreme situations of common point failure of the main and backup rings through a temporary transmission path mechanism, ensuring that the interaction data between multi-source signals and nodes is uninterrupted, and guaranteeing the continuity of emergency communication and public communication in the tunnel.

[0079] This embodiment provides a method for a tunnel-embedded multi-source full-area coverage repeater system as described above in a second aspect, the method comprising: Step 1: Deploy repeater modules. The repeater modules are embedded into the tunnel sidewall using a tunnel-embedded deployment structure, and multiple repeater modules are connected through cascading interfaces to form a cascading network. Step 2: Transmission layer processing, which directly amplifies and forwards the received multi-source signals using radio frequency pass-through technology without signal demodulation or encoding, and simultaneously uses time-domain synchronization technology to synchronize the characteristics of the multi-source signals to achieve consistency of the multi-source signal characteristics; wherein, the multi-source signals include 4G, 5G and CATV signals; Step 3: Collaboration layer processing, including: Step 31: Detect the frequency band type of the multi-source signal using the frequency band identification module; Step 32: The coverage weight of the multi-source signals is dynamically adjusted based on signal strength, user density, and interference level using the weight calculation module; Step 33: Control the transmit power of each frequency band based on the adjustment results of the coverage weight through the power allocation module; Step 34: The signal processing module performs coupling processing on multi-band signals, isolation processing on signals of different frequency bands, and combining and transmission processing on multi-band signals. Step 4: Algorithm layer processing, including: Step 41: Construct a tunnel topology model that includes the tunnel geometry and signal propagation characteristics using the tunnel topology modeling module; Step 42: Analyze the signal data exchanged between adjacent repeater nodes via RS485 or long-distance radio technology using the signal strength prediction module to predict the signal coverage strength of each area; Step 43: The power optimization module automatically adjusts the transmission power based on the signal coverage strength prediction results; Step 5: Transmission protection processing. Through link monitoring, dual-ring network control and fiber optic self-healing switching mechanism, the status of the fiber optic transmission channel connecting each repeater module is monitored and anomalies are handled to ensure reliable transmission of multi-source signals and node interaction data.

[0080] It should be noted that this method corresponds to the aforementioned tunnel-embedded multi-source full-area coverage repeater system. Therefore, for the contents not specifically described in this method (including but not limited to specific technical means and effects), please refer to the relevant descriptions in the aforementioned tunnel-embedded multi-source full-area coverage repeater system. This text will not elaborate on these contents here.

[0081] In the embodiments provided in this application, it should be understood that the embodiments described herein can be implemented in hardware, software, firmware, middleware, code, or any suitable combination thereof. For hardware implementation, the processor may be implemented in one or more of the following: application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, other electronic units designed to implement the functions described herein, or combinations thereof. For software implementation, some or all of the processes of the embodiments may be performed by a computer program instructing the associated hardware. During implementation, the program may be stored in a computer-readable storage medium or transmitted as one or more instructions or code on a computer-readable storage medium. Computer-readable storage media include computer storage media and communication media, wherein communication media include any medium that facilitates the transmission of a computer program from one place to another. Storage media may be any available medium accessible to a computer. Computer-readable storage media may include, but are not limited to, RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code having the form of instructions or data structures and accessible to a computer.

[0082] Finally, it should be noted that the above description is only a preferred embodiment of this application and is not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A multi-source global coverage repeater system in a tunnel-embedded mode, comprising a tunnel-embedded deployment structure and repeater modules, the repeater modules being embedded in a tunnel side wall through the tunnel-embedded deployment structure, and a plurality of the repeater modules being connected through cascade interfaces to form a cascade network; characterized in that, The repeater module comprises: A transparent layer, which directly amplifies and forwards the received multi-source signals through radio frequency direct transmission technology without signal demodulation or coding processing, and synchronously processes the characteristics of the multi-source signals through time domain synchronization technology to achieve consistency of the characteristics of the multi-source signals; wherein the multi-source signals include 4G, 5G and CATV signals; A coordination layer, which comprises a frequency band identification module, a weight calculation module, a power distribution module and a signal processing module; wherein the frequency band identification module is used for detecting the frequency band types of the multi-source signals, the weight calculation module is used for dynamically adjusting the coverage weights of the multi-source signals according to signal strength, user density and interference level, the power distribution module is used for controlling the transmission power of each frequency band based on the adjustment results of the coverage weights, and the signal processing module is used for coupling processing of multi-frequency band signals, isolation processing of different frequency band signals and combined transmission processing of multi-frequency band signals; An algorithm layer, which comprises a tunnel topology modeling module, a signal strength prediction module and a power optimization module; wherein the tunnel topology modeling module is used for constructing a tunnel topology model of tunnel geometric structure and signal propagation, the signal strength prediction module is used for analyzing the signal data exchanged by adjacent repeater nodes through RS485 or long-distance radio technology to predict the signal coverage strength of each area, and the power optimization module is used for automatically adjusting the transmission power based on the prediction results of the signal coverage strength.

2. The multi-source re-broadcasting station system according to claim 1, wherein, The transparent layer comprises a signal receiving module, a wideband filtering module, a synchronization processing module, a delay adjustment module and a radio frequency direct transmission amplification module; The signal receiving module is used for capturing multi-source signals through a wideband antenna array and converting them into initial multi-source radio frequency electrical signals; The wideband filtering module is used for screening out the corresponding target frequency band components in the received initial multi-source radio frequency electrical signals, removing interference signals of non-target frequency bands, and retaining pure multi-source signals; The synchronization processing module is used for extracting synchronization identifiers from reference signals or pure multi-source signals issued by a base station, constructing a unified time domain reference framework, comparing the time domain characteristics of each pure multi-source signal with the time domain reference framework, and calculating the time domain deviation data of each signal; The delay adjustment module is used for adjusting the delay time of the signal transmission path according to the time domain deviation data output by the synchronization processing module, so that the phase difference of all pure multi-source signals in the time domain is controlled within a preset range, and a synchronized multi-source signal is obtained; The radio frequency direct transmission amplification module is used for directly amplifying the synchronized multi-source signal without signal demodulation or coding processing to maintain the original modulation mode and coding structure of the signal, and transmitting the amplified multi-source signal to the coordination layer.

3. The multi-source global coverage repeater system of claim 2, wherein, The synchronization processing module comprises a feature extraction unit and a deviation calculation unit; The feature extraction unit is used for analyzing the time domain characteristic parameters of the pure multi-source signals and transmitting the time domain characteristic parameters to the deviation calculation unit; The deviation calculation unit is used for comparing the time domain characteristic parameters of each pure multi-source signal with the standard parameters in the framework one by one based on the constructed time domain reference framework, and calculating the time delay value and phase shift of each signal. The delay adjustment module comprises a programmable delay unit and a phase calibration unit; The programmable delay unit is used for compensating the transmission path of the corresponding pure multi-source signal based on the time delay value, and the phase calibration unit is used for correcting the phase deviation of the signal by adjusting the phase compensation device of the signal transmission circuit according to the phase offset; In the delay compensation and phase deviation correction process, the deviation calculation unit collects the signal characteristics after adjustment in real time, and compares them with the time domain reference framework again, and if the deviation of a signal still exceeds the preset range, a recalibration instruction is sent to the delay adjustment module until the time domain characteristics of all pure multi-source signals are consistent with the reference framework, forming a synchronized multi-source signal.

4. The multi-source global coverage repeater system of claim 1, wherein, The dynamic adjustment of the coverage weight of the multi-source signal according to the signal intensity, user density and interference degree comprises: Collecting real-time signal intensity data of each frequency band signal, user density data of each area in the tunnel, and interference degree data between each frequency band signal from the multi-source signal; According to the principle of preferentially increasing the weight of the corresponding frequency band in the signal intensity insufficient area, adapting the high weight signal in the high user density area, and reducing the weight of the serious interference frequency band, the coverage weight of each frequency band signal is dynamically adjusted, and finally the weight distribution result of each frequency band is output.

5. The multi-source global coverage repeater system of claim 4, wherein, The control of the transmission power of each frequency band signal based on the coverage weight result output by the weight calculation module comprises: The power distribution module converts the coverage weight of each frequency band into the corresponding power distribution proportion, and divides the total transmission power resource of the system; More power resources are allocated to the frequency band signal with high weight proportion to enhance its coverage ability, and adaptive basic power is allocated to the frequency band signal with low weight proportion to meet the basic coverage demand; meanwhile, the power distribution module monitors the actual transmission power data of each frequency band signal in real time, and compares the monitored data with the allocated power proportion, and adjusts the power amplification link of the corresponding frequency band if there is a deviation.

6. The multi-source global coverage repeater system of claim 1, wherein, The construction process of the tunnel topology model comprises: The tunnel topology modeling module acquires geometric structure original data and signal propagation characteristic original data of the tunnel; The acquired original data is preprocessed to remove measurement errors in the geometric structure data and correct environmental interference in the signal propagation characteristic data; Based on the preprocessed geometric structure data, a tunnel three-dimensional grid model is constructed, and the installation positions of the curves, obstacles and repeater modules in the tunnel are marked; Based on the preprocessed signal propagation characteristic data, the tunnel three-dimensional grid model is formed by assigning corresponding attenuation coefficients and reflection coefficients to different areas.

7. The multi-source global coverage repeater system of claim 6, wherein, The prediction of the signal coverage intensity of each area comprises: The signal intensity prediction module receives the exchange data sent by the adjacent repeater modules, analyzes the exchange data, and extracts the current signal intensity value, transmission power value and installation position coordinates of each adjacent repeater module; Input the parsed information of the adjacent repeater modules into the tunnel topology model, determine the coverage range boundaries of each adjacent repeater module, and the relative position relationship between the to-be-predicted area and each adjacent repeater module; Based on the signal propagation characteristic parameters of the to-be-predicted area in the tunnel topology model, the transmission loss of the signal from the adjacent repeater modules to the to-be-predicted area is calculated through a signal propagation prediction algorithm according to the transmission power and the relative position of the adjacent repeater modules; According to the current signal strength value of the adjacent repeater modules and the calculated transmission loss, the signal coverage intensity prediction value of the to-be-predicted area is obtained, and the area whose prediction value is lower than the preset blind area determination threshold is marked as a potential coverage blind area.

8. The multi-source global coverage repeater system of claim 7, wherein, The automatic adjustment of the transmission power based on the signal coverage intensity prediction result comprises: The power optimization module receives the coverage intensity prediction value of each area and the marking of the potential coverage blind area output by the signal strength prediction module; the prediction result is classified and judged: if the coverage intensity prediction of a certain area is higher than the preset blind area determination threshold and there is no overlapping interference risk, the current transmission power is maintained; if a certain area is a potential coverage blind area, the transmission power of the corresponding repeater module needs to be increased; if the coverage intensity prediction value of the area where the coverage ranges of two or more repeater modules overlap exceeds the preset overlapping anti-interference threshold, the transmission power of at least one repeater module needs to be reduced to avoid interference; For the case where the power needs to be adjusted, the required power adjustment amplitude is calculated according to the difference between the coverage intensity prediction value of each area and the corresponding preset blind area determination threshold and the signal propagation loss coefficient of the tunnel in that area; The power optimization module sends a power adjustment instruction to the corresponding repeater module, and the repeater module responds to the power adjustment instruction and controls the built-in power amplification circuit to change the output power; After the power adjustment is completed, the power optimization module obtains the adjusted coverage intensity prediction value of the area through the signal strength prediction module, repeats the classification and judgment to verify the adjustment effect, and if there is still a case where the power needs to be adjusted, the adjustment amplitude is repeatedly calculated and executed until the tunnel global coverage meets the standard.

9. The multi-source global coverage repeater system of claim 1, wherein, The tunnel-embedded multi-source global coverage repeater system also comprises a transmission protection mechanism; the transmission protection mechanism comprises a link monitoring module, a dual-ring network control module and an optical fiber self-healing switching module; The link monitoring module is used to collect the link state data of the optical fiber transmission channel connecting each repeater module in the tunnel, which is used to transmit multi-source signals and node interaction data, and compare the collected link state data with a preset normal threshold; if the link state data exceeds the threshold, it is determined that the link is abnormal, and an abnormal alarm signal is output; The dual-ring network control module is used to construct a primary and backup dual-ring transmission link, and the optical fiber interfaces of all repeater modules in the tunnel are connected to the primary ring link and the backup ring link respectively; the primary ring link is used to transmit the multi-source signals of the daily transmission transparent layer and the adjacent node signal data required by the algorithm layer; the backup ring link is used to synchronously transmit the key data of the primary ring link, which includes the real-time signal strength, the current transmission power and the link state data of each repeater module; The optical fiber self-healing switching module is used for triggering self-healing protection when a link is abnormal, and in response to an abnormal alarm signal, it locates the abnormal link position and starts the self-healing switching logic: if the abnormality occurs in the main ring link, the transmission load of the main ring link is switched to the backup ring link, and the signal input of the main ring link is cut off at the same time; If the backup ring link synchronously detects an abnormality, the dual-ring network control module constructs a temporary transmission path through other normal nodes and performs link switching; After switching is completed, the link monitoring module continuously collects link state data after switching, verifies whether transmission is restored to normal, and if so, maintains the current link transmission; if it is still abnormal, the self-healing switching logic is repeated until the optical fiber transmission channel restores reliable transmission.

10. A method applied to the tunnel type multi-source global coverage repeater system as claimed in any one of claims 1 to 9, characterized in that, The method comprises: Step 1: deploying a repeater module, embedding the repeater module in the tunnel side wall through a tunnel-embedded deployment structure, and connecting multiple repeater modules through a cascade interface to form a cascade network; Step 2: transparent layer processing, directly amplifying and forwarding the received multi-source signals through radio frequency direct transmission technology, without signal demodulation or encoding processing, and synchronously processing the characteristics of the multi-source signals through time domain synchronization technology to realize the consistency of the characteristics of the multi-source signals; wherein the multi-source signals include 4G, 5G and CATV signals; Step 3: cooperative layer processing, including: Step 31: detecting the frequency band type of the multi-source signals through a frequency band identification module; Step 32: dynamically adjusting the coverage weight of the multi-source signals according to signal strength, user density and interference level through a weight calculation module; Step 33: controlling the transmission power of each frequency band based on the adjustment result of the coverage weight through a power distribution module; Step 34: coupling processing of multi-band signals, isolation processing of different frequency band signals, and combined transmission processing of multi-band signals through a signal processing module; Step 4: algorithm layer processing, including: Step 41: constructing a tunnel topology model containing tunnel geometric structure and signal propagation characteristics through a tunnel topology modeling module; Step 42: analyzing the signal data exchanged by adjacent repeater nodes through RS485 or long-distance radio technology to predict the signal coverage strength of each area through a signal strength prediction module; Step 43: automatically adjusting the transmission power based on the signal coverage strength prediction result through a power optimization module; Step 5: transmission protection processing, through link monitoring, dual-ring network control and optical fiber self-healing switching mechanism, the state of the optical fiber transmission channel connecting each repeater module is monitored and abnormality is handled to ensure reliable transmission of multi-source signals and node interaction data.

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