Tunnel leaky cable communication system

Abstract

The embodiment of the utility model provides a tunnel leaky coaxial cable communication system. The tunnel leaky coaxial cable communication system comprises: at least one information source module, wherein the at least one information source module is installed at a preset point location in a tunnel; the input end of the multi-system combining platform is connected with at least one information source module and a direct-current power supply; the system comprises a multi-system combining platform, at least two sections of leaky coaxial cables, the at least two sections of leaky coaxial cables comprise an end side leaky coaxial cable, the input end of the end side leaky coaxial cable is connected with the output end of the multi-system combining platform, and two adjacent sections of leaky coaxial cables are connected through a relay unit. According to the scheme, continuous coverage of the long tunnel is achieved through relay unit cascading, unified access and composite transmission of frequency bands of multiple operators are achieved through the multi-system combining platform, repeated wiring is reduced, the resource utilization rate is increased, and the method adapts to complex space structures such as tunnel bending sections.

Description

Technical Field

[0001] This application relates to the field of wireless technology, specifically to a tunnel leaky cable communication system. Background Technology

[0002] In enclosed or semi-enclosed environments such as tunnels, the transmission of wireless communication signals is severely limited by physical barriers, mainly manifested in problems such as drastic signal attenuation and limited coverage. The shielding effect of the concrete or rock layers in tunnel structures on electromagnetic waves makes it difficult for traditional wireless communication methods to achieve effective coverage. Currently, leaky coaxial cable (LCC) is mainly used as the signal transmission medium in tunnels. It achieves longitudinal transmission and lateral radiation of electromagnetic waves through slots in the outer conductor, thereby forming a uniform signal field strength within the tunnel. A leaky cable system typically consists of a signal source, a remote radio unit (RRU), the leaky cable, and a point-of-integration (POI) device, and achieves long-distance coverage through segmented deployment.

[0003] The transmission attenuation and coupling loss of existing leaky cables increase with frequency, leading to a shortened coverage distance per cable. For example, in the 3.5GHz band, a leaky cable experiences approximately 6dB of attenuation per 100 meters, theoretically covering only 300 meters. Since signal and power sources are fixed within tunnels, medium-to-long tunnels (e.g., over 3 kilometers) require frequent additions of signal sources and leaky cables, further increasing deployment costs and wasting resources. Instantaneous user traffic within the coverage area of ​​a single leaky cable fluctuates significantly, making it difficult to fully utilize new signal sources and resulting in idle network resources. Furthermore, leaky cable installation requires strict adherence to spacing and bending radius requirements, leading to high construction complexity, and improper waterproofing and moisture-proofing of joints can easily cause signal interruptions. Utility Model Content

[0004] At least one embodiment of this application provides a tunnel leaky cable communication system to solve the problems of increased high-frequency loss and limited coverage distance, as well as low resource utilization and complex operation and maintenance.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] This application provides a tunnel leaky cable communication system, including:

[0007] At least one signal source module, and at least one of the signal source modules is installed at a predetermined point in the tunnel;

[0008] A multi-system combining platform, wherein the input terminal of the multi-system combining platform is connected to at least one of the signal source modules and a DC power supply;

[0009] At least two leakage cables, the at least two leakage cables including one end-side leakage cable, an input end of the end-side leakage cable being connected with an output end of the multi-system combining platform, and two adjacent leakage cables being connected through a relay unit.

[0010] Optionally, the relay unit includes:

[0011] A first combiner, an input end of the first combiner being connected with a leakage cable in a source direction; the source direction being a direction from the source module to the relay unit;

[0012] A second combiner, an output end of the second combiner being connected with a leakage cable in a relay direction; the relay direction being a direction from the relay unit to a next leakage cable or a coverage area;

[0013] At least one set of relay amplification channel circuits, an input end of each set of the relay amplification channel circuits being connected with an output end of the first combiner, an output end of each set of the relay amplification channel circuits being connected with an input end of the second combiner, each set of the channel circuits being used for transmitting signals of a preset frequency band and standard;

[0014] A detection unit, connected with each set of the relay amplification channel circuits.

[0015] Optionally, the relay unit further includes:

[0016] A power management unit, receiving a direct current power signal from the first combiner and supplying power for the relay unit;

[0017] A control unit, connected with the detection unit, the power management unit and each set of the relay amplification channel circuits.

[0018] Optionally, the relay amplification channel circuit includes:

[0019] A duplexer or a radio frequency switch;

[0020] An attenuator, an input end of the attenuator being connected with the duplexer or the radio frequency switch;

[0021] A low noise amplifier, connected with the attenuator;

[0022] An adjustable attenuator, connected with the low noise amplifier;

[0023] A filter, connected with the adjustable attenuator;

[0024] A power amplifier, an output end of the power amplifier being connected with the duplexer or the radio frequency switch.

[0025] Optionally, the power management unit includes:

[0026] A voltage stabilizing module for converting an input direct current into a stable voltage;

[0027] A multiplexing module receives the voltage signal output by the voltage stabilizing module and inputs the voltage signal to the low-noise amplifier, the power amplifier and the control unit in the relay amplification channel circuit.

[0028] Optionally, the relay amplification channel circuit further comprises:

[0029] A temperature compensation module is integrated at an output end of the power amplifier.

[0030] A waterproof sealed cavity covers all active devices in the relay amplification channel circuit, and a heat-conducting silicone layer is arranged on a surface of the cavity.

[0031] A modular plug-in interface connects the relay amplification channel circuit, the first combiner and the second combiner.

[0032] Optionally, the leaky cable is a coaxial leaky cable, and an outer conductor of the coaxial leaky cable is provided with a plurality of slot structures.

[0033] Compared with the prior art, the tunnel leaky cable communication system comprises at least one signal source module, at least one of the signal source modules is installed at a preset point in a tunnel, a multi-system combining platform, an input end of the multi-system combining platform is connected with at least one of the signal source modules and a direct current power supply, and at least two sections of leaky cables, the at least two sections of leaky cables comprise an end-side leaky cable, an input end of the end-side leaky cable is connected with an output end of the multi-system combining platform, and adjacent two sections of leaky cables are connected through a relay unit. The scheme of the present application realizes long-tunnel continuous coverage through relay unit cascading, realizes unified access and composite transmission of multiple operator frequency bands through the multi-system combining platform, reduces repeated wiring and improves resource utilization, and is suitable for complex spatial structures such as tunnel curved sections. BRIEF DESCRIPTION OF DRAWINGS

[0034] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The detailed description is made with reference to the accompanying drawings.

[0035] Figure 1 A structural schematic diagram of a tunnel leaky cable communication system provided by an embodiment of the present application;

[0036] Figure 2 A structural schematic diagram of a relay unit provided by an embodiment of the present application.

[0037] Explanation of reference signs:

[0038] 1: source module; 2: multi-system combining platform; 3: DC power supply; 4: end-side leak cable; 5: leak cable; 6: relay unit. DETAILED DESCRIPTION

[0039] In the embodiments of the present application, the term "and / or" describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. The character " / " generally represents an "or" relationship between the associated objects before and after it.

[0040] In the embodiments of the present application, the term "multiple" means two or more, and other quantifiers are similar.

[0041] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0042] Please refer to Figure 1 The embodiments of the present application provide a tunnel leak cable 5 communication system, which comprises:

[0043] At least one source module 1, at least one of the source modules 1 is installed at a preset point in the tunnel;

[0044] A multi-system combining platform 2, the input end of the multi-system combining platform 2 is connected with at least one of the source modules 1 and a DC power supply 3;

[0045] At least two sections of leak cable 5, the at least two sections of leak cable 5 include an end-side leak cable 4, the input end of the end-side leak cable 4 is connected with the output end of the multi-system combining platform 2, and adjacent two sections of leak cable 5 are connected through a relay unit 6.

[0046] In the embodiments of the present application, each system source (such as a fifth-generation mobile communication 5G base station, a Beidou positioning repeater) is deployed at a preset point in the tunnel, and is fed into a multi-system combining platform (POI) together with a DC power supply. The POI needs to support DC signal transmission, which realizes the integration of the source and the power supply. At this time, the leak cable has dual functions of signal transmission / radiation and relay unit power supply. The relay unit is segmented and covered: the leak cable is connected to the relay unit (Repeater) 6 at the edge of the coverage, compensates the signal attenuation through a low-noise amplifier (LNA) and a power amplifier (PA), and then connected to the next section of leak cable. If there is still a coverage requirement, the structure can be repeated to realize multi-stage relay.

[0047] For example, by using a high-frequency low-loss leaky cable (such as a 3.6G frequency leaky cable), the 3.5GHz frequency band has a comprehensive loss as low as 0.07dB / m, supports 700-3600MHz frequency band, and can realize high-frequency signal transmission optimization. The outer conductor adopts an eight-shaped slot hole design, combined with a foamed polyethylene-fluoroplastic composite material, to reduce high-frequency coupling loss. The leaky cable core and the shielding layer form a direct current power supply channel, and through the automatic tail cutting function, fault isolation is realized: when a short circuit is detected, the field effect transistor quickly cuts off the power supply of the fault section, ensuring the normal work of the front-end relay unit, and realizing direct current power supply and fault isolation.

[0048] Optionally, the POI combining platform combines signals such as 5G (3.4-3.6GHz), Beidou (1268 / 1561MHz), and broadcast (88-108MHz), with an insertion loss of ≤0.8dB, reducing the hardware deployment amount by 60%.

[0049] Optionally, the coverage distance of a single section of leaky cable is extended from 300 meters in the traditional scheme to 500 meters, and only 3 signal sources are needed for a 3-kilometer tunnel, saving 40% of the comprehensive cost compared to the traditional scheme, and greatly improving the coverage capability.

[0050] It should be noted that the input end of the end-side leaky cable 4 is directly connected to the output end of the multi-system combining platform 2, the POI platform integrates multi-operator 5G signals and Beidou positioning signals, and through the combining and splitting technology, the composite transmission of multi-frequency signals in the leaky cable is realized, avoiding the waste of resources caused by independent deployment of multiple cables. The wideband characteristics of the leaky cable support the compatibility of CDMA, WLAN and other systems, ensuring the stable transmission of signals of different systems. The two adjacent leaky cables 5 are connected through the relay unit 6, and the relay unit integrates a fiber optic repeater remote unit to complete the conversion and amplification of optical-electrical signals and compensate for the attenuation of high-frequency signals in long-distance transmission. The relay unit 6 supports dynamic power adjustment, balances the signal strength in the tunnel (such as high at both ends and low in the middle), and improves the uniformity of coverage.

[0051] It should also be noted that the end-side leaky cable 4 is only provided in one section, which is the front section of the leaky cable; the leaky cable 5 is the rear section of the leaky cable, and the leaky cable 5 can have multiple sections, and a relay unit 6 is provided between the end-side leaky cable 4 and the leaky cable 5, or between the leaky cable 5 and the leaky cable 5.

[0052] The POI platform of the present application aggregates multi-frequency signals, and uniformly accesses the end-side leaky cable, reducing repeated wiring and improving resource utilization. The relay unit cascades the optical fiber repeater technology, a single section of leaky cable covers 600 meters, supports long tunnel continuous coverage, and the relay unit supports remote monitoring and automatic technology implementation. This scheme realizes the direct connection of the end-side leaky cable and the POI, cascades the relay unit, and intelligently manages, solves the problems of high-frequency signal loss, long-distance coverage limitation, and multi-system coexistence, and is suitable for complex tunnel scenarios.

[0053] The scheme of the application solves the problems of high frequency loss, resource waste and complex operation and maintenance of the traditional leaky cable system through high frequency signal enhancement, relay cascade and intelligent operation and maintenance technology, and provides a high cost-effective solution for tunnel communication.

[0054] Referring to Figure 2 As shown in the figure, the relay unit 6 comprises:

[0055] A first combiner (combiner 1) whose input end is connected with a leaky cable 5 in the source direction; the source direction is the direction from the source module 1 to the relay unit 6;

[0056] A second combiner (combiner 2) whose output end is connected with a leaky cable 5 in the relay direction; the relay direction is the direction from the relay unit 6 to the next section of leaky cable 5 or the coverage area;

[0057] At least one set of relay amplification channel circuits, the input end of each set of relay amplification channel circuits is connected with the output end of the first combiner, the output end of each set of relay amplification channel circuits is connected with the input end of the second combiner, and each set of channel is used for transmitting signals of a preset frequency band and a preset standard;

[0058] A detection unit connected with each set of relay amplification channel circuits.

[0059] In the embodiment of the application, based on the double-combiner architecture and the multi-channel relay amplification technology, long-distance low-loss transmission of high-frequency signals and intelligent monitoring are realized. The first combiner (combiner 1) integrates signals in the source direction, and the input end of the first combiner is connected with a leaky cable 5 in the source direction (i.e. the leaky cable section from the source module 1 to the relay unit 6), and receives multi-band signals (such as operator 5G frequency band, Beidou positioning signal) from the source. The output end of the first combiner: through a multi-system combining platform (POI), the signals are branched to different relay amplification channel circuits to avoid mutual interference of multi-band signals. The first combiner is built-in with a reactive circuit, which reduces signal reflection loss through impedance matching (<0.5 dB) to ensure the transmission efficiency of high-frequency signals. The input end of the second combiner (combiner 2) receives signals (processed by amplification and filtering) from the relay amplification channel circuit. The output end of the second combiner (combiner 2) is connected with a leaky cable 5 in the relay direction (i.e. the leaky cable section from the relay unit 6 to the next section of leaky cable or the coverage area), and the composite signal is radiated to the tunnel coverage area through the leaky cable. Figure 2 The structure of the dashed box in the figure is a relay amplification channel circuit; each set of channel of the application independently processes preset frequency band signals (for example: channel-1 is dedicated to 3.5GHz 5G signal, and channel-2 is dedicated to 2.6GHz LTE signal); the relay amplification channel circuit of the application adopts the optical fiber repeater remote machine technology to complete the optical-electric conversion and power amplification, and compensates the transmission loss of the leaky cable.

[0060] The relay unit 6 of the present application monitors the signal power, intermodulation interference (IMD) and equipment temperature of each group of relay amplification channels in real time, and uploads data to the remote operation and maintenance platform. A coupler is arranged between the combiner 1 and the duplex filter to collect residual intermodulation signals, and automatically adjust the channel gain after triggering the alarm threshold. The ground fault is detected through the elastic deformation body connecting structure, and the remote platform is combined to realize rapid fault isolation.

[0061] Optionally, the working process of the relay unit 6 is as follows: the signal source module outputs a multi-frequency signal → the leakage cable 5 transmits the signal to the combiner 1 → the signal is split to each relay amplification channel. Each channel is independently amplified and filtered → the signals are combined by the combiner 2 → the signals are output to the relay direction leakage cable 5 for radiation coverage. The detection unit feeds back the channel state in real time, dynamically adjusts the power and heat dissipation, and ensures the stability of the relay unit 6.

[0062] Optionally, the relay amplification channel circuit comprises:

[0063] a duplex filter or a radio frequency switch;

[0064] an attenuator, an input end of the attenuator being connected to the duplex filter or the radio frequency switch;

[0065] a low noise amplifier, connected to the attenuator;

[0066] an adjustable attenuator, connected to the low noise amplifier;

[0067] a filter, connected to the adjustable attenuator;

[0068] a power amplifier, an output end of the power amplifier being connected to the duplex filter or the radio frequency switch.

[0069] In the embodiment of the present application, the duplex filter / radio frequency switch is used to select the split mode according to the signal standard (such as FDD / TDD), and isolate the interference of uplink and downlink signals. For example, the radio frequency switch timing switching can be controlled through the synchronization signal to avoid the conflict between receiving and transmitting. The attenuator is used to attenuate the input level to prevent overload; the low noise amplifier is used to provide a preset range of gain, and the noise coefficient is controlled to be lower than a certain value to ensure the quality of weak signals; the attenuator is used to adjust the input level to prevent overload. The adjustable attenuator dynamically balances the channel gain and adapts to the radiation loss of the leakage cable. The power amplifier is used to output power greater than a preset value, which can support long-distance transmission of high-frequency signals.

[0070] Optionally, the relay amplification channel circuit further comprises:

[0071] a temperature compensation module, integrated in the output end of the power amplifier;

[0072] a waterproof sealed cavity, covering all active devices in the relay amplification channel circuit, and a heat-conducting silicone layer is arranged on the surface of the cavity;

[0073] A modular plug-in interface connects the relay amplification channel circuit, the first combiner, and the second combiner.

[0074] In the present application, the temperature compensation module is integrated at the output end of the power amplifier, and the temperature drift is offset by a negative feedback circuit. The waterproof sealed cavity can adopt an IP67 protection level, and the surface of the cavity is coated with a heat-conducting silicone layer to improve the heat dissipation and moisture-proof performance. The modular plug-in interface is used to support the quick connection (insertion loss ≤ 0.3 dB) of the relay channel and the combiner, facilitating the replacement of faulty components.

[0075] Optionally, the relay unit 6 further comprises:

[0076] A power management unit receives the DC power supply 3 signal from the first combiner and supplies the DC power supply 3 to the relay unit 6;

[0077] A control unit connected to the detection unit, the power management unit, and each group of relay amplification channel circuits.

[0078] Optionally, the power management unit comprises:

[0079] A voltage stabilizing module for converting the input DC voltage into a stable voltage;

[0080] A multi-channel distribution module that receives the voltage signal output by the voltage stabilizing module and inputs it to the low-noise amplifier, the power amplifier, and the control unit in the relay amplification channel circuit.

[0081] In the present application, the 48V DC input from the leaky cable is converted into a stable voltage (±5% fluctuation tolerance), and 12V / 5V is output for use by the low-noise amplifier, control unit, etc. The multi-channel distribution module is used to distribute power to the power amplifier, low-noise amplifier, and control unit as needed, greatly improving efficiency. The detection unit of the present application collects channel signal power, power amplifier temperature, and intermodulation distortion in real time. The control unit dynamically adjusts the gain of the adjustable attenuator, the bias voltage of the power amplifier, and the speed of the cooling fan according to the detection data, optimizes the energy efficiency ratio, and realizes the synergy of detection and control.

[0082] Optionally, the leaky cable 5 is a coaxial leaky cable, and the outer conductor is provided with a plurality of slotted structures.

[0083] The outer conductor of the coaxial leaky cable of the present application is periodically slotted (slot pitch λ / 4, λ is 3.5 GHz wavelength), and the radiation efficiency is improved, and the coverage density is adjustable to adapt to the curved section of the tunnel.

[0084] In summary, the present application has the following effects:

[0085] (1) Linear coverage structure innovation: adopt "source-leaky cable-relay-leaky cable" cascade architecture, compensate high frequency signal attenuation through relay unit, solve the problem of limited coverage of high frequency band of traditional leaky cable.

[0086] (2) Multi-band multi-channel repeater design: the repeater adopts multi-band multi-channel parallel structure, supports independent control and simultaneous amplification of 5G, Beidou, broadcast and other multi-system signals. For example, a certain filter combining platform can combine three signals (3.4-3.6GHz, 1268 / 1561MHz, 88-108MHz), and the insertion loss is ≤0.8dB.

[0087] (3) DC power supply system integration: multiplex the DC power supply at the source, form a power supply channel through the core wire and the shielding layer of the leaky cable, realize the integration of "signal transmission + power supply". Compared with traditional AC power supply, the DC system reduces line loss, and supports seamless connection with renewable energy such as photovoltaic and energy storage, improving green and low-carbon benefits.

[0088] It should be noted that in this article, the term "includes", "contains" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or includes elements inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0089] The embodiments of the present application are described above in combination with the drawings, but the present application is not limited to the above specific embodiments, and the above specific embodiments are only illustrative, not restrictive, and those skilled in the art can make many forms under the inspiration of the present application without departing from the scope of the present application and the scope protected by the claims.

Claims

1. A tunnel leaky cable communication system characterized by, The application relates to a tunnel leakage cable system. The application comprises: at least one source module, which is installed at a preset point in a tunnel; a multi-system combination platform, the input end of which is connected with at least one source module and a direct-current power supply; 2. The tunnel leaky cable communication system of claim 1, wherein, at least two sections of leakage cable, the input end of an end-side leakage cable being connected with the output end of the multi-system combination platform, and adjacent two sections of leakage cable being connected through a relay unit. The relay unit comprises: a first combiner, the input end of which is connected with a source-direction leakage cable; the source direction is the direction from the source module to the relay unit; a second combiner, the output end of which is connected with a relay-direction leakage cable; the relay direction is the direction from the relay unit to the next section of leakage cable or a coverage area; at least one set of relay amplification channel circuit, the input end of each set of relay amplification channel circuit being connected with the output end of the first combiner, and the output end of each set of relay amplification channel circuit being connected with the input end of the second combiner, each set of channel being used for transmitting signals of a preset frequency band and mode; 3. The tunnel leaky cable communication system according to claim 2, wherein, a detection unit, which is connected with each set of relay amplification channel circuit. The relay unit further comprises: a power management unit, which receives a direct-current power supply signal from the first combiner and supplies power for the relay unit; 4. The tunnel leaky cable communication system of claim 3, wherein, a control unit, which is connected with the detection unit, the power management unit and each set of relay amplification channel circuit. The relay amplification channel circuit comprises: a duplexer or a radio frequency switch; an attenuator, the input end of which is connected with the duplexer or the radio frequency switch; a low-noise amplifier, which is connected with the attenuator; an adjustable attenuator, which is connected with the low-noise amplifier; a filter, which is connected with the adjustable attenuator; 5. The tunnel leaky cable communication system of claim 4, wherein, a power amplifier, the output end of which is connected with the duplexer or the radio frequency switch. The power management unit comprises: a voltage stabilizing module, which is used for converting an input direct-current into a stable voltage; 6. The tunnel leaky cable communication system of claim 4, wherein, a multi-channel distribution module, which receives a voltage signal output by the voltage stabilizing module and inputs the voltage signal into the low-noise amplifier, the power amplifier and the control unit in the relay amplification channel circuit. The relay amplification channel circuit further comprises: a temperature compensation module, which is integrated at the output end of the power amplifier; a waterproof sealed cavity, which covers all active devices in the relay amplification channel circuit, and a heat-conducting silica gel layer is arranged on the surface of the cavity; 7. The tunnel leaky cable communication system of claim 1, wherein, a modular plug-in interface, which is connected with the relay amplification channel circuit, the first combiner and the second combiner. The leakage cable is a coaxial leakage cable, and the outer conductor of the coaxial leakage cable is provided with a plurality of slot structures.

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