Subway rail transit underground space emergency communication system and arrangement method thereof

Abstract

The invention relates to the field of mobile data communication services, in particular to a subway rail transit underground space emergency communication system and an arrangement method thereof. The subway rail transit underground space emergency communication system provided by the invention comprises a first communication link used for transmitting service data in a first state; the second communication link is used for transmitting service data in a second state; the communication link monitoring module is in signal connection with the first communication link and is used for monitoring the signal-to-noise ratio of data transmission in the first communication link; and the communication link switching module is in signal connection with the communication link monitoring module, is respectively in signal connection with the first communication link and the second communication link, and is used for switching the data transmission path from the first communication link to the second communication link according to the signal-to-noise ratio of data transmission in the first communication link. According to the invention, through double-link redundancy and rapid switching, automatic switching to a standby link is realized under abnormal conditions such as optical fiber faults or power interruption, and continuous and uninterrupted communication is ensured.

Description

Technical Field

[0001] This invention relates to the field of mobile data communication services, and more particularly to an emergency communication system for underground spaces in subway rail transit and its deployment method. Background Technology

[0002] In normal operation, subway communication relies on distributed antenna systems or ray feeders directly connected to ground base stations, which can meet the needs of daily dispatching and passenger service. However, in extreme emergency scenarios such as sudden fires, power outages, fiber optic cable breaks, or earthquakes, single-path or single-power supply modes are prone to communication blind spots, switching delays, or equipment power failures, causing the command center and on-site personnel to lose timely communication, affecting the efficiency of accident handling and endangering life safety. Summary of the Invention

[0003] In a first aspect, the present invention provides an emergency communication system for underground space in subway rail transit, comprising: The first communication link is used to transmit service data in the first state; The second communication link is set up in parallel with the first communication link and is used to transmit service data in the second state. A communication link monitoring module is connected to the signal of the first communication link and is used to monitor the signal-to-noise ratio of data transmission in the first communication link; The communication link switching module is signal-connected to the communication link monitoring module and signal-connected to the first communication link and the second communication link respectively. It is used to switch the data transmission path from the first communication link to the second communication link according to the signal-to-noise ratio of the data transmission in the first communication link.

[0004] In some examples, the first communication link in the emergency communication system for underground space of subway rail transit provided by the present invention is provided by a dual-fiber ring network. The dual-fiber ring network includes a first transmission fiber and a second transmission fiber that are independent of each other. The first transmission fiber and the second transmission fiber are both laid in a ring topology and are used to provide a first-first communication link and a first-second communication link that are redundant with each other.

[0005] In some examples, the emergency communication system for underground space in subway rail transit provided by the present invention further includes: The dual-fiber loop network monitoring module is connected to the first and second communication links respectively, and is used to monitor the signal-to-noise ratio of data transmission in the first and second communication links.

[0006] In some examples, the emergency communication system for underground space in subway rail transit provided by the present invention further includes: The dual-fiber ring network link switching module is used to switch the data transmission path from the first communication link to the second communication link based on the signal-to-noise ratio of the data transmission in the first and second communication links.

[0007] In some examples, the emergency communication system for underground space of subway rail transit provided by the present invention provides a second communication link through a plurality of relay nodes via wireless transmission. The plurality of relay nodes are spaced apart on the path of the dual-fiber ring network. Each relay node is equipped with a dual-frequency Mesh wireless communication module, a first SFP interface and a second SFP interface. The first SFP interface is used to plug into the first transmission fiber of the first communication link, and the second SFP interface is used to plug into the second transmission fiber of the second communication link.

[0008] In some examples, the emergency communication system for underground space of subway rail transit provided by the present invention includes a communication link monitoring module comprising several communication link monitoring sub-modules, which are respectively set in the several relay nodes. Each communication link monitoring sub-module is used to collect the signal-to-noise ratio of data transmission in the first communication link within the corresponding communication link segment.

[0009] In some examples, the emergency communication system for underground space of subway rail transit provided by the present invention includes a communication link switching module comprising several communication link switching sub-modules, which are respectively set in the several relay nodes. Any one of the communication link switching modules is used to switch the data transmission path from the first communication link to the second communication link according to the signal-to-noise ratio of the data transmission in the first communication link in the corresponding communication link segment.

[0010] In some examples, the emergency communication system for underground space of subway rail transit provided by the present invention also includes a power supply module in any relay node. The power supply module is electrically connected to the communication link monitoring submodule and the communication link switching submodule in the same relay node, and is used to supply power to the communication link monitoring submodule and the communication link switching submodule in the same relay node.

[0011] In some examples, the emergency communication system for underground space of subway rail transit provided by the present invention uses an edge computing unit as the communication link switching module to autonomously complete the judgment and execution of communication link switching.

[0012] Secondly, based on the emergency communication system for underground space of subway rail transit provided in the first aspect, the present invention also provides a deployment method for deploying the emergency communication system for underground space of subway rail transit provided in the first aspect in a subway rail transit environment, comprising the following steps: Determine the installation location of the relay node; Reserve fiber optic ducts and node mounting rails at the top of the tunnel or in the tunnel equipment area; A first transmission optical fiber and a second transmission optical fiber are laid inside the optical fiber duct; At each installation location, a repeater node is installed, and at each installation location, the first transmission fiber and the second transmission fiber are plugged into the first SFP interface and the second SFP interface in the corresponding repeater node.

[0013] The emergency communication system and its deployment method for underground space in subway rail transit provided by this invention include, but are not limited to, the following gains: This invention achieves automatic switching to a backup link in case of fiber optic failure or power outage through dual-link redundancy and rapid switching, ensuring uninterrupted communication. Furthermore, it employs a ring-shaped dual-fiber network for parallel transmission, combined with online monitoring technology, enabling accurate fault monitoring and diagnosis, improving network availability and maintainability. Further, through distributed intelligence, each relay node possesses edge computing capabilities, autonomously performing link status analysis and routing decisions, reducing central control pressure and enhancing system adaptability and self-healing capabilities. Finally, through simplified deployment and expansion, it utilizes a modular design combined with reserved conduits and rail-mounted installation, simplifying the construction process and supporting subsequent capacity expansion, thus improving deployment efficiency. Attached Figure Description

[0014] Figure 1 A first schematic diagram of the composition of an emergency communication system for underground space in subway rail transit provided as an example of the present invention; Figure 2 A second schematic diagram of the composition of an emergency communication system for underground space in subway rail transit provided as an example of the present invention; Figure 3 This invention provides an example of an underground emergency communication system for subway rail transit, illustrating the connection between a relay node and the first and second transmission optical fibers; and Figure 4 The flowchart illustrates the layout of an emergency communication system for underground space in subway rail transit, as provided in this invention. Detailed Implementation

[0015] In the following description, specific details such as particular systems, structures, and techniques are set forth for illustrative purposes rather than limiting, in order to provide a thorough understanding of the examples in this application. Those skilled in the art will understand that this application can also be implemented in other examples without these specific details.

[0016] In the description of this application, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted to avoid unnecessary detail from obscuring the description. Furthermore, it should be noted that terms such as "first" and "second" are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0017] Existing underground emergency communication systems typically use distributed antenna systems or ray feeders directly connected to ground base stations to achieve data transmission and communication. However, this approach involves a large amount of construction work, high maintenance costs, and is prone to communication blind spots in extreme scenarios such as fiber optic cable breakage, power outages, or fires.

[0018] To address the problems existing in the prior art, in one example of the present invention, the following is provided: Figure 1 The emergency communication system for underground space of subway rail transit shown includes a first communication link, a second communication link, a communication link monitoring module, and a communication link switching module.

[0019] Furthermore, the first communication link and the second communication link are configured in parallel and connected to the ground base station respectively. It is understood that the ground base station described in this example refers to base station equipment located within a ground command center and connected to the first and second communication links.

[0020] In this example, the first communication link is used to transmit service data in a first state. It should be noted that the first state is the normal communication state, which is characterized by the signal-to-noise ratio in the first communication link being equal to or higher than a preset threshold.

[0021] In this example, the second communication link is used to transmit service data in the second state. It should be noted that the second state is the abnormal communication state, which is characterized by the signal-to-noise ratio in the first communication link being lower than a preset threshold.

[0022] It is understood that the aforementioned preset threshold refers to the lowest acceptable value of the signal-to-noise power ratio (SNR) at the receiving end in the first communication link, used to determine whether the quality of the main link meets the requirements of normal service. Typically, this preset threshold ranges from 12dB to 18dB, with a commonly used value of 15dB. In this example, to ensure communication stability and timely handover in the complex environment of a subway tunnel, the preset threshold is set to 15dB.

[0023] Furthermore, the communication link monitoring module is connected to the first communication link signal and is used to monitor the signal-to-noise ratio of data transmission in the first communication link; the communication link switching module is connected to the communication link monitoring module and is also connected to the first communication link and the second communication link signal respectively, and is used to switch the data transmission path from the first communication link to the second communication link according to the signal-to-noise ratio of data transmission in the first communication link.

[0024] To provide a highly reliable data transmission link in underground environments and enable rapid fault recovery, in one example provided by this invention, the first communication link proposed in the above example is provided by a dual-fiber ring network. It should be noted that the dual-fiber ring network proposed in this example refers to a transmission backbone within the tunnel and station equipment area, employing two physically independent single-mode optical fibers laid in a ring topology with mutual redundancy.

[0025] Furthermore, the dual-fiber ring network provided in this example includes a first transmission fiber and a second transmission fiber that are independent of each other. Both the first and second transmission fibers are laid in a ring topology and are used to provide redundant first-to-first and first-to-second communication links, respectively. That is, the first and second transmission fibers start from the ground base station, pass sequentially through relay nodes along the top of the tunnel or equipment area, and finally return to the ground base station, forming two closed physical loops. In some embodiments, both the first and second transmission fibers are made of G.652D single-mode fiber, which has low attenuation, wide bandwidth, and long-distance transmission capabilities.

[0026] To enable communication link switching within a dual-fiber ring network, in one example of the present invention, the emergency communication system for underground space of subway rail transit further includes: a dual-fiber ring network monitoring module, which is connected to the first communication link and the first second communication link respectively, for monitoring the signal-to-noise ratio of data transmission in the first communication link and the first second communication link.

[0027] In some embodiments, the dual-fiber loop network monitoring module collects the signal-to-noise ratio (SNR) of the two fiber loops at a period of 200ms or other preset sampling periods: if the SNR of the current communication link is continuously lower than 15dB, link switching is immediately triggered.

[0028] Furthermore, in this example, the emergency communication system for underground space in subway rail transit also includes a dual-fiber ring network link switching module, used to switch the data transmission path from the first communication link to the second communication link based on the signal-to-noise ratio of the data transmission in the first communication link and the second communication link. It should be noted that the switching operation between the first and second communication links is only performed when the signal-to-noise ratio of at least one communication link in the first communication link reaches or exceeds a preset threshold.

[0029] In order to efficiently switch to a backup link for reliable data transmission in the event of a fiber optic failure, in one example of the present invention, the second communication link in the emergency communication system for underground space of subway rail transit is realized by several relay nodes through wireless transmission.

[0030] like Figure 2 and Figure 3As shown, several relay nodes are set at intervals along the path of the dual fiber optic ring. Each relay node is equipped with a dual-frequency Mesh wireless communication module, a first SFP interface and a second SFP interface. The first SFP interface is used to connect the optical fiber of the first communication link, and the second SFP interface is used to connect the optical fiber of the second communication link.

[0031] It should be noted that the spatial interval between any two adjacent relay nodes on a dual-fiber ring network needs to be determined based on the effective transmission distance of the dual-frequency Mesh wireless communication module configured on the relay node.

[0032] Specifically, the effective transmission distance mentioned above is constrained by factors such as the operating frequency band of the dual-frequency Mesh wireless communication module, maximum transmit power, receiver sensitivity, tunnel cross-section attenuation characteristics, and multipath effect. Therefore, in straight sections, it is preferable to control the interval between adjacent relay nodes within the range of 300 to 500 m. In shield tunnel sections, curved sections, or areas with significant structural obstacles, this interval can be further shortened to 200 to 300 m to ensure that the second communication link transmitted via Mesh wireless can still meet the target communication needs in the event of failure of the first communication link or emergency.

[0033] Furthermore, in this example, the communication link monitoring module in the emergency communication system for underground space of subway rail transit also includes several communication link monitoring sub-modules, which are respectively set in the several relay nodes. Each communication link monitoring sub-module is used to collect the signal-to-noise ratio of data transmission in the first communication link within the corresponding communication link segment.

[0034] It should be noted that the communication link segment mentioned in this example refers to the transmission interval formed by the corresponding optical fiber connection between any two adjacent smart repeater nodes in an optical fiber ring network; specifically, it refers to the optical fiber length range covered by the single-mode optical fiber laid along the pre-buried duct from the first or second SFP interface output end of a certain repeater node to the first or second SFP interface input end of its next adjacent repeater node; for example, a 350-meter section of G.652D single-mode optical fiber between node A and node B at the top of the tunnel constitutes a communication link segment in this example.

[0035] Furthermore, in this example, the communication link switching module in the emergency communication system for underground space of subway rail transit includes several communication link switching sub-modules, which are respectively set in the several relay nodes. Any one of the communication link switching modules is used to switch the data transmission path from the first communication link to the second communication link according to the signal-to-noise ratio of the data transmission in the first communication link in the corresponding communication link segment.

[0036] It should be noted that in most practical application scenarios, the first communication link often only experiences a break or performance degradation in a local area. Therefore, in this example, the communication link switching module only performs switching on the communication link segment detected as abnormal, without needing to perform a full link switch. Specifically, it includes the following steps: (1) When a communication link monitoring submodule detects that the signal-to-noise ratio in its corresponding communication link segment is lower than a preset threshold, the sub-communication link monitoring submodule sends a switching signal to the communication link switching submodule in the same relay node; (2) The communication link switching submodule uses the first and last relay nodes of the link segment as the switching anchor points, and only switches the transmission path of the service data from the first communication link to the second communication link within the corresponding communication link segment; (3) After the handover, the service data is relayed along the Mesh wireless network for at least one hop in the corresponding communication link segment until it is reconnected to the next available first communication link node; (4) When the communication link monitoring submodule detects that the signal-to-noise ratio of this communication link segment is higher than or equal to the preset threshold, the communication link switching submodule automatically switches in the opposite direction to restore the original optical fiber transmission path.

[0037] Understandably, this partial handover mechanism only calls the backup link for the affected section, while the remaining link segments continue to transmit normally along the main link, which can greatly reduce the load on the Mesh network and improve the system handover efficiency.

[0038] In this example, to ensure efficient link switching, the communication link switching module is an edge computing unit that can autonomously complete the communication link switching judgment and execution.

[0039] It is understandable that the communication link switching module in any relay node integrates independent computing and storage resources to complete functions such as communication link status determination, switching strategy generation, and command execution locally, without relying on a remote command center or upper-level cloud platform.

[0040] To ensure stable data transmission and normal operation of backup lines during power outages, in one example provided by this invention, a power supply module is also provided in any relay node. The power supply module is electrically connected to the communication link monitoring submodule and the communication link switching submodule in the same relay node, and is used to supply power to the communication link monitoring submodule and the communication link switching submodule in the same relay node.

[0041] To ensure independent power supply, the power module includes an independent power source, such as a battery; in other examples, to achieve continuous power supply, the power module consists of an AC input unit, a UPS uninterruptible power supply, a battery pack, a micro-vibration energy harvester, a DC / DC converter, and a battery management system (BMS).

[0042] Furthermore, during continuous power supply, the mains input unit converts AC mains power into DC power to supply the various electronic modules of the relay node; when the mains power is interrupted, the UPS automatically switches to battery power supply within a preset time limit, and the DC / DC converter outputs the required DC voltage; the battery pack preferably uses 48V / 10Ah lithium-ion batteries, which can provide continuous power supply for more than 4 hours in the event of a power outage; the micro-vibration energy harvester uses tunnel vibration to assist in charging the battery pack, thereby extending the power outage time; the BMS provides overcharge, over-discharge, over-temperature and short-circuit protection, and reports the battery charge status in real time for operation and maintenance monitoring.

[0043] To facilitate installation and subsequent maintenance, the emergency communication system for underground space in subway rail transit provided by this invention, in one example, uses, as shown in... Figure 4 The installation and layout shall be carried out as shown: S01. Determine the installation location of the relay node.

[0044] Furthermore, after completing the surveying of the tunnel and station structures, the installation points of relay nodes (IRNs) were determined based on the communication link coverage and Mesh wireless transmission capabilities.

[0045] In one specific embodiment, the base spacing is 300m to 500m in straight sections, and shortened to 200m to 300m in curved sections, shield tunnel sections, or areas with dense obstacles. It is understood that in other embodiments, the relay node spacing can be adjusted to adapt to different geological conditions, vibration energy harvesting efficiency, and wireless signal attenuation characteristics.

[0046] S02. Reserve fiber optic ducts and node mounting rails at the top of the tunnel or in the tunnel equipment area.

[0047] Furthermore, after completing step S01, based on the marked relay node location and pipeline route, pre-embedded pipelines and rail installation are carried out on the load-bearing structure of the tunnel top or station equipment area to meet the requirements of subsequent fiber optic laying and relay node sliding installation.

[0048] Understandably, the relay nodes are slid in and locked in by pre-installed rails, avoiding secondary damage to the main tunnel structure and enabling rapid placement and disassembly of the nodes without relying on temporary supports.

[0049] Furthermore, the uniform dimensions and strict parallelism of the mounting rails ensure the consistency of the height and position of each node chassis and the pre-embedded pipe outlet, eliminating manual positioning deviations and ensuring precise alignment of the fiber optic pigtails with the SFP interface and power interface.

[0050] Compared to traditional bolt drilling or welding methods, rail mounting causes less disruption to operations during construction and significantly reduces the manpower and material resources required for installation and maintenance. Furthermore, using industry-standard rails ensures compatibility with node chassis of different sizes and manufacturers, providing exceptional flexibility for future expansion or module upgrades.

[0051] S03. Lay the first transmission optical fiber and the second transmission optical fiber inside the optical fiber duct.

[0052] Furthermore, after completing the installation of the rails and the pre-reservation of the duct, the two pre-selected optical cables should be inserted into the optical fiber sleeve in parallel, serving as the first transmission optical fiber and the second transmission optical fiber, respectively.

[0053] Ideally, the minimum bending radius of the optical cable should always be kept at no less than 30mm during the laying process, and the cable should be supported by guide wheels or pulleys at regular intervals to prevent stress concentration or breakage. At the same time, tension monitoring equipment should be used to control the traction force to no more than 50N to avoid micro-bending loss caused by excessive tension.

[0054] It is important to note that the two optical cables should be color-coded at the duct entrance, and distance and ring number markings should be periodically printed on the sheaths for subsequent maintenance and location. After laying, at least 1.5m of pigtail should be reserved in the fusion splice box corresponding to the repeater node, and thermal splicing and waterproof and vibration-proof fixing should be performed according to relevant recommended standards. Subsequently, end-to-end insertion loss and return loss tests should be performed on both optical fibers to ensure that the attenuation value of each link meets the design requirements.

[0055] S04. Install a relay node at each installation location, and connect the first transmission fiber and the second transmission fiber to the first SFP interface and the second SFP interface in the corresponding relay node at each installation location.

[0056] Furthermore, at each reserved mounting position, the relay node chassis integrating the power module, edge computing unit, and Mesh wireless module will be slid into the node guide rail and locked with stainless steel bolts. After the chassis is installed, the first transmission fiber optic pigtail should be inserted into the first SFP interface input of this node, and the second transmission fiber optic pigtail should be inserted into the second SFP interface input, ensuring that the interfaces are not loose and maintain the minimum bending radius. Fiber optic cable management racks should be configured inside the node to fix the pigtails to prevent fiber displacement due to vibration or subsequent maintenance operations.

[0057] After the node is powered on, it starts a self-test program to check whether the status of the two SFP optical link lights is normal. Finally, the service flow is verified under two working conditions: the main link is normal and the main link is broken. This confirms that the system can complete the switching and reconnection from fiber to Mesh wireless within the target time limit, thereby ensuring the system deployment quality and emergency switching performance.

[0058] In the examples above, the descriptions of each example have their own emphasis. For parts that are not described or recorded in detail in a certain example, please refer to the relevant descriptions in other examples.

[0059] It should be noted that the above examples can be freely combined as needed. The above are merely preferred embodiments of the present invention; it should be observed that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An emergency communication system for underground space in subway rail transit, characterized in that, include: The first communication link is used to transmit service data in the first state; The second communication link is set up in parallel with the first communication link and is used to transmit service data in the second state. A communication link monitoring module is connected to the signal of the first communication link and is used to monitor the signal-to-noise ratio of data transmission in the first communication link; The communication link switching module is signal-connected to the communication link monitoring module and signal-connected to the first communication link and the second communication link respectively. It is used to switch the data transmission path from the first communication link to the second communication link according to the signal-to-noise ratio of the data transmission in the first communication link.

2. The emergency communication system for underground space in subway rail transit according to claim 1, characterized in that, The first communication link is provided by a dual-fiber ring network, which includes a first transmission fiber and a second transmission fiber that are independent of each other. The first transmission fiber and the second transmission fiber are both laid in a ring topology and are used to provide a first-first communication link and a first-second communication link that are redundant with each other.

3. The emergency communication system for underground space in subway rail transit according to claim 2, characterized in that, Also includes: The dual-fiber loop network monitoring module is connected to the first and second communication links respectively, and is used to monitor the signal-to-noise ratio of data transmission in the first and second communication links.

4. The emergency communication system for underground space in subway rail transit according to claim 3, characterized in that, Also includes: The dual-fiber ring network link switching module is used to switch the data transmission path from the first communication link to the second communication link based on the signal-to-noise ratio of the data transmission in the first and second communication links.

5. The emergency communication system for underground space in subway rail transit according to claim 2, characterized in that, The second communication link is provided by a number of relay nodes via wireless transmission. The relay nodes are spaced apart on the path of the dual-fiber ring network. Each relay node is equipped with a dual-frequency Mesh wireless communication module, a first SFP interface and a second SFP interface. The first SFP interface is used to connect to the first transmission fiber of the first communication link, and the second SFP interface is used to connect to the second transmission fiber of the second communication link.

6. The emergency communication system for underground space in subway rail transit according to claim 5, characterized in that, The communication link monitoring module includes several communication link monitoring sub-modules, which are respectively set in the several relay nodes. Each communication link monitoring sub-module is used to collect the signal-to-noise ratio of data transmission in the first communication link within the corresponding communication link segment.

7. The emergency communication system for underground space in subway rail transit according to claim 6, characterized in that, The communication link switching module includes several communication link switching sub-modules, which are respectively set in the several relay nodes. Any one of the communication link switching modules is used to switch the data transmission path from the first communication link to the second communication link according to the signal-to-noise ratio of the data transmission in the first communication link in the corresponding communication link segment.

8. The emergency communication system for underground space in subway rail transit according to claim 6, characterized in that, Each relay node is also equipped with a power supply module, which is electrically connected to the communication link monitoring submodule and the communication link switching submodule within the same relay node, and is used to supply power to the communication link monitoring submodule and the communication link switching submodule within the same relay node.

9. The emergency communication system for underground space of subway rail transit according to any one of claims 1-8, characterized in that, The communication link switching module is an edge computing unit used to autonomously complete the judgment and execution of communication link switching.

10. A deployment method, said deployment method being used in a subway rail transit environment to deploy the subway rail transit underground space emergency communication system as described in any one of claims 5-9, characterized in that, Includes the following steps: Determine the installation location of the relay node; Reserve fiber optic ducts and node mounting rails at the top of the tunnel or in the tunnel equipment area; A first transmission optical fiber and a second transmission optical fiber are laid inside the optical fiber duct; At each installation location, a repeater node is installed, and at each installation location, the first transmission fiber and the second transmission fiber are plugged into the first SFP interface and the second SFP interface in the corresponding repeater node.

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