Wireless communication network system

Abstract

The present disclosure provides a wireless communication network system including: a first communication device disposed outside a tunnel; the at least one second communication device is arranged in the tunnel, the first communication device is in communication connection with the at least one second communication device through an optical fiber, and the at least one second communication device is configured to receive a signal sent by the first communication device through the optical fiber and send the signal in the tunnel.

Description

Technical Field

[0001] The present disclosure relates to the field of communications, and in particular to a wireless communication network system. Background Art

[0002] Tunnel construction is a complex and technically demanding engineering activity. Especially with the increasing popularity of mechanical automation and intelligence, communication technology in the construction process is particularly important. Traditional tunnel construction communication mainly relies on wired methods, which not only limits the mobility of construction machinery, but also the wiring work itself has many inconveniences and safety hazards in such a closed and complex space as the tunnel.

[0003] With the development of wireless communication technology, wireless networks have gradually become a new choice for communication in tunnel construction. Summary of the invention

[0004] The inventors noticed that the existing technology has significant defects in tunnel construction communication. First, the wireless signal coverage is not comprehensive, especially in the deep tunnel, the signal attenuation is serious, resulting in communication blind spots. Second, when multiple machines work together, interference is likely to occur between communication devices, affecting the communication quality. In addition, the existing technology is not adaptable enough to environmental changes in the tunnel, and it is difficult to meet dynamic construction needs. These defects limit construction efficiency and increase safety risks.

[0005] Accordingly, the present disclosure provides a wireless communication network system that can effectively achieve wireless network coverage that meets the needs of multi-machine collaborative operations in a tunnel environment.

[0006] In a first aspect of the present disclosure, there is provided a wireless communication network system, comprising: a first communication device, arranged outside a tunnel; and at least one second communication device, arranged inside the tunnel, wherein the first communication device is communicatively connected to the at least one second communication device via an optical fiber, and the at least one second communication device is configured to receive a signal sent by the first communication device via the optical fiber, and send the signal in the tunnel.

[0007] In some embodiments, the first communication device is a baseband unit BBU; and the second communication device is a radio remote unit RRU.

[0008] In some embodiments, the network system further includes a leaky cable, wherein the at least one RRU device is configured to feed the signal into the leaky cable so as to transmit the signal in the tunnel.

[0009] In some embodiments, the at least one RRU device includes one RRU device.

[0010] In some embodiments, when the length of the tunnel is less than the single-side coverage distance of the RRU device, the RRU device is arranged at the entrance or exit of the tunnel.

[0011] In some embodiments, when the length of the tunnel is less than the coverage distance of the RRU device and not less than the single-side coverage distance of the RRU device, the RRU device is arranged in the middle area of ​​the tunnel.

[0012] In some embodiments, the at least one RRU device includes a plurality of RRU devices;

[0013] In some embodiments, when the length of the tunnel is not less than the coverage distance of the RRU device, the multiple RRU devices are arranged inside the tunnel, wherein the interval between two adjacent RRU devices is not greater than the coverage distance of the RRU devices.

[0014] In some embodiments, a special antenna is set at a turn in the tunnel, wherein the special antenna is electrically connected to the RRU device and is used to send the signal in the tunnel.

[0015] In some embodiments, a first directional antenna is provided at the exit of the tunnel, wherein the first directional antenna is electrically connected to the RRU device, for transmitting the signal to the outside of the tunnel.

[0016] In some embodiments, a second directional antenna is provided at the entrance of the tunnel, wherein the second directional antenna is electrically connected to the RRU device, for transmitting the signal to the outside of the tunnel.

[0017] In some embodiments, the first communication device is a near-end machine; and the at least one second communication device is a far-end machine.

[0018] In some embodiments, the remote unit is configured to receive a signal sent by the near-end unit via an optical fiber, and forward the signal in the tunnel via an antenna.

[0019] In some embodiments, the optical fiber comprises a low smoke zero halogen flame retardant optical cable.

[0020] In some embodiments, a physical isolation device is provided between the optical fiber and the high-voltage cable in the tunnel to reduce interference of the high-voltage cable on the optical fiber.

[0021] In some embodiments, the network system further includes: a plurality of wireless access points disposed on the palm face, wherein the plurality of wireless access points are communicatively connected to the first communication device via optical fibers.

[0022] In some embodiments, the wireless access point includes at least one of a pico base station or a WIFI access point.

[0023] In some embodiments, the network system also includes: a resource scheduling controller, configured to allocate a first bandwidth to the multiple wireless access points and a second bandwidth to the at least one second communication device when the engineering machinery located at the face is in a working state, wherein the first bandwidth is greater than the second bandwidth.

[0024] In some embodiments, the resource scheduling controller is configured to allocate reserved bandwidth resources to the multiple wireless access points when a traffic peak is detected on the engineering machinery.

[0025] In some embodiments, the resource scheduling controller is configured to allocate a third bandwidth to the multiple wireless access points and a fourth bandwidth to the at least one second communication device when the engineering machinery located at the tunnel face is in a non-working state, wherein the third bandwidth is smaller than the fourth bandwidth.

[0026] Other features and advantages of the present disclosure will become apparent from the following detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0028] Figure 1 A schematic diagram of the structure of a wireless communication network system according to an embodiment of the present disclosure;

[0029] Figure 2 A schematic diagram of the structure of a wireless communication network system according to another embodiment of the present disclosure;

[0030] Figure 3 A schematic diagram of the structure of a wireless communication network system according to another embodiment of the present disclosure;

[0031] Figure 4 A schematic diagram of the structure of a wireless communication network system according to another embodiment of the present disclosure;

[0032] Figure 5 A schematic diagram of the structure of a wireless communication network system according to another embodiment of the present disclosure;

[0033] Figure 6The present invention is a structural diagram of a wireless communication network system according to another embodiment of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present disclosure and its application or use. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0035] Unless specifically stated otherwise, the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure.

[0036] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0037] Technologies, methods, and apparatus known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, such technologies, methods, and apparatus should be considered part of the authorization specification.

[0038] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0039] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0040] The inventors have noticed that with the development of wireless communication technology, wireless networks have gradually become a new choice for communication in tunnel construction. However, existing wireless communication technologies face many challenges in the special environment of tunnels. First, the closed structure and complex terrain conditions of the tunnel will have a significant impact on the propagation of wireless signals, resulting in rapid signal attenuation and uneven coverage. Secondly, when multiple construction machines are operating at the same time in the tunnel, a large number of communication signals will be generated. These signals are prone to interfere with each other, affecting the stability and reliability of communication. In addition, the dynamic changes in the tunnel construction environment, such as the advancement of construction progress and changes in the position of machinery, also put forward higher requirements on the adaptability and flexibility of wireless networks.

[0041] Although some technologies have been used to try to solve these problems, such as expanding coverage by adding signal relay equipment, or using frequency planning and channel allocation techniques to reduce interference, these methods often have problems such as high cost, complex deployment, and poor dynamic adaptability.

[0042] Accordingly, the present disclosure provides a wireless communication network system that can effectively achieve wireless network coverage that meets the needs of multi-machine collaborative operations in a tunnel environment.

[0043] Figure 1 A schematic diagram of the structure of a wireless communication network system according to an embodiment of the present disclosure.

[0044] like Figure 1 As shown, the wireless communication network system includes a first communication device 11 and at least one second communication device 12. As an example, Figure 1 Two second communication devices 12 are shown.

[0045] The first communication device 11 is provided outside the tunnel 10 .

[0046] The at least one second communication device 12 is arranged inside the tunnel 10, wherein the first communication device 11 is communicatively connected to the at least one second communication device 12 via the optical fiber 13, and the at least one second communication device 12 is configured to receive the signal sent by the first communication device 11 via the optical fiber 12, and send the received signal in the tunnel 10.

[0047] It should be noted here that since the signal will not be affected by the complex environment in the tunnel during transmission in the optical fiber, the transmission quality of the signal is effectively improved.

[0048] In some embodiments, the optical fiber comprises a low-smoke, halogen-free, flame-retardant optical cable to ensure safety.

[0049] For example, optical fiber can be laid along the weak current channel in the tunnel. A docking optical cross-connection box should be installed outside the fence at the tunnel entrance to achieve smooth docking of optical cables inside and outside the red line. As for the core connection of the optical cable to each equipment point, a divergent connection or a ring connection can be used to improve the flexibility and reliability of the connection.

[0050] In some embodiments, a physical isolation device is provided between the optical fiber and the high-voltage cable in the tunnel to reduce the interference of the high-voltage cable on the optical fiber.

[0051] For example, if optical fiber needs to be laid in a railway power channel, physical isolation measures should be implemented between the optical fiber and the power cable to reduce potential interference between the two. This can be achieved by using flame-retardant troughs or tubes, isolation hooks and other isolation equipment.

[0052] In some embodiments, Figure 1 In the embodiment, the first communication device 11 is a BBU (Baseband Unit), and the second communication device 12 is a RRU (Remote Radio Unit).

[0053] Figure 2 A structural diagram of a wireless communication network system according to another embodiment of the present disclosure.

[0054] like Figure 2 As shown, the BBU 21 is arranged outside the tunnel 10. The at least one RRU 22 is arranged inside the tunnel 20, wherein the BBU 21 is communicatively connected with the at least one RRU 22 via an optical fiber 23, and the at least one RRU 22 is configured to receive a signal sent by the BBU 21 via the optical fiber 23, and feed the received signal into the leaky cable 24 via a multiplex input and output (POI) combiner, so as to send the signal in the tunnel 20, thereby achieving full coverage of the signal in the tunnel.

[0055] For example, BBU equipment is installed in the operator's room outside the railway safety line at the tunnel entrance. RRU equipment is reasonably configured in key locations such as the tunnel entrance station, the communication cavern, the cable excess length chamber, the comprehensive cavern and the power cavern according to the RRU spacing allowed by the link budget.

[0056] It should be noted here that when the wavelength of the electromagnetic wave is less than half the diameter of the outer conductor of the leaky cable, the signal will be reflected inside the cable and cannot be transmitted effectively. After testing and analysis, the theoretical cutoff frequency of the 13 / 8-inch leaky cable is about 2.7GHz, while the theoretical cutoff frequency of the 5 / 4-inch leaky cable is about 3.7GHz. Taking into account the different frequencies of different operators, for example, the frequency of China Mobile 5G is 2.6GHz, and the frequency of China Telecom and China Unicom 5G is 3.5GHz, a 5 / 4-inch leaky cable is selected to ensure that each RRU device can cover an area of ​​about 250 meters.

[0057] In addition, in order to ensure signal coverage at the tunnel entrance, a field station is usually set up at the tunnel entrance to install the RRU and antennas of each system. When laying out the macro base station closest to the tunnel entrance, the extended coverage range of the tunnel entrance antenna of the Telecom / Unicom 5G system must also be considered.

[0058] In some embodiments, the at least one RRU device includes one RRU device, that is, only one RRU device is arranged in the tunnel.

[0059] For example, when the length of the tunnel is less than the single-side coverage distance of the RRU device, the RRU device is arranged at the entrance or exit of the tunnel.

[0060] For example, for a short tunnel, if its length is less than 250 meters, that is, less than the single-side coverage distance of the RRU equipment (250 meters), you can choose to install the RRU at the entrance or exit of the tunnel according to the terrain conditions and power access points at the tunnel entrance. The RRU can be installed in a cabinet or installed on a steel pole at the field leveling station together with the antenna.

[0061] In some embodiments, when the length of the tunnel is less than the coverage distance of the RRU device and not less than the single-side coverage distance of the RRU device, the RRU device is set in the middle area of ​​the tunnel to achieve full coverage of the signal in the tunnel.

[0062] For example, for a short tunnel, if its length is greater than 250 meters and less than 500, that is, greater than the single-sided coverage distance of the RRU device (250 meters) and less than the coverage distance of the RRU device (500 meters), you can choose to install the RRU in the middle area of ​​the tunnel based on the terrain conditions and power access points at the tunnel entrance, so as to achieve full signal coverage in the tunnel.

[0063] In some embodiments, the at least one RRU device includes multiple RRU devices, that is, multiple RRU devices are arranged in the tunnel.

[0064] For example, when the length of the tunnel is not less than the coverage distance of the RRU devices, a plurality of RRU devices are arranged inside the tunnel, wherein the interval between two adjacent RRU devices is not greater than the coverage distance of the RRU devices.

[0065] For example, for a longer tunnel, if the length exceeds 500 meters, multiple RRU devices can be installed in appropriate locations based on the terrain conditions at the tunnel entrance and the available space in the tunnel, and the spacing between adjacent RRU devices can be set to 500 meters, thereby using leaky cables to achieve full signal coverage in the tunnel.

[0066] In some embodiments, the wireless communication network system further includes: a first directional antenna disposed at the exit of the tunnel, wherein the first directional antenna is electrically connected to the RRU device and is used to send the signal to the outside of the tunnel, thereby ensuring that the coverage of the signal is extended to the outside of the tunnel. Thus, when the communication device leaves the tunnel from the tunnel exit, it is ensured that the network environment does not suddenly change.

[0067] In some embodiments, the wireless communication network system further comprises: a second directional antenna disposed at the entrance of the tunnel, wherein the second directional antenna is electrically connected to the RRU device and is used to send the signal to the outside of the tunnel, thereby ensuring that the coverage of the signal is extended to the outside of the tunnel. Thus, when the communication device leaves the tunnel from the entrance of the tunnel, it is ensured that the network environment does not suddenly change.

[0068] In some embodiments, the wireless communication network system further includes: a special antenna disposed at a turn in the tunnel, wherein the special antenna is electrically connected to the RRU device for sending signals in the tunnel.

[0069] It should be noted here that special antennas are favored for their flexibility and scalability. They are usually installed at the same point as the RRU equipment and connected through jumpers. Within the coverage range, points can be set as needed, or points can be set for signal weak points in the covered area to achieve supplementary signal depth coverage. Especially in the turning area of ​​the tunnel, since the signal strength may drop significantly, setting antenna points in these areas can ensure the continuity and stability of the signal.

[0070] Here, we take the special antenna accessing the 2.6G frequency band as an example to calculate the coverage distance. According to the wireless propagation model, the maximum allowable path loss is shown in formula (1).

[0071] 32.5+20×log(F)+20×log(1000×R)(1)

[0072] In formula (1), F is the frequency band, in MHz, which is 2600 MHz here; R is the coverage radius, in m.

[0073] For example, when the base station transmission power is set to 12dBm, the antenna gain is set to 13dBi, the equipment body loss is set to 25dB, and the edge field strength requirement is -105dBm, after link loss, the maximum allowable path loss is 92.5dB. According to the wireless propagation model formula, it can be calculated that the coverage radius of the special antenna is approximately 385m. In the case of a straight line, the spacing between special antennas can reach more than 700m, and the coverage effect is particularly obvious for straight tunnels.

[0074] For example, Figure 3 As shown, the test tunnel 30 is 1.2 km long and has two turning points on the way. Three RRU points are set here, namely: one point is set at each end of the tunnel, namely RRU 31 and RRU 32, so as to achieve signal coverage in the middle direction of the tunnel, and RRU 33 is set at one point in the middle of the tunnel, so as to achieve signal coverage in the direction of both ends of the tunnel. Since there is obvious attenuation at the two turning points of the tunnel, special antennas 34 and characteristic antennas 35 can be added as needed to improve the signal coverage effect.

[0075] In some embodiments, Figure 1 In the embodiment, the first communication device 11 is a near-end device, and the at least one second communication device 12 is a far-end device.

[0076] It should be noted here that when it is not suitable to deploy leaky cables, digital wireless fiber optic repeaters can be used for deployment.

[0077] Figure 4 The present invention is a structural diagram of a wireless communication network system according to another embodiment of the present invention.

[0078] like Figure 4 As shown, the remote unit 42 is configured to receive the signal sent by the near-end unit 41 through the optical fiber 43 and forward the signal in the tunnel 40 through the antenna.

[0079] It should be noted here that the near-end machine uses a receiving antenna to capture wireless signals, and converts them into the CPRI (Common Public Radio Interface) standard format through digital processing, and then transmits them to the remote machine through optical fiber. After receiving the data in CPRI format, the remote machine performs digital-to-analog conversion, and regenerates and amplifies the RF signal to achieve remote coverage of the base station signal. This digital fiber repeater has higher output power, lower noise coefficient and longer transmission distance, and will not interfere with the base station when multiple remote coverage, making the network more flexible. In addition, the delay of the remote overlapping coverage area can be adjusted. These advantages together enhance the remote coverage capability of the base station signal. This can effectively solve the network coverage problems in signal blind spots and weak areas, improve the channel utilization of the main base station, and improve the problem of poor network coverage.

[0080] The near-end machine captures the spatial RF signals from the communication base station outside the tunnel through a directional antenna, digitizes and converts these signals into photoelectric signals, and then transmits them to the far-end machine through optical fiber. After receiving the signal, the far-end machine digitizes and converts it into photoelectric signals again, and performs RF amplification. Finally, the directional antenna covers the signal inside the tunnel, completing the remote coverage of the base station signal.

[0081] During the entire transmission process, the digital signal and the optical signal are independent of each other, and the digital signal is not affected by the attenuation of the optical signal, thereby eliminating the loss of the wireless signal path between the base station and the repeater. Even in long-distance and high-speed transmission, it can maintain a high dynamic range, ensure signal quality, and make full use of spectrum resources and network equipment. This is equivalent to establishing a two-way transparent channel between the base station and the mobile phone, extending the coverage of the wireless signal.

[0082] For example, the near-end machine is equipped with four optical ports, each of which can connect up to 8 remote machines in series, and can support up to 32 remote machines in total. This flexible and changeable networking mode includes point-to-point, star, daisy chain and hybrid networking, etc., which can build a distributed coverage system and achieve wide coverage. Therefore, the system is particularly suitable for areas such as tunnels and underground pipe galleries that require long-distance strip coverage.

[0083] Figure 5The present invention is a structural diagram of a wireless communication network system according to another embodiment of the present invention.

[0084] like Figure 5 As shown, the wireless communication network system includes a plurality of wireless access points 53 arranged in a palm face 50, a first communication device 51 (for example, Figure 2 The BBU 21) in the network is connected to multiple wireless access points 53 through rHUB 52 and optical fiber.

[0085] For example, the wireless access point 52 includes at least one of a pico base station pRRU or a WIFI access point.

[0086] It should be noted here that for users who can use the public network, have extremely high latency requirements, and have many obstacles on the construction site, only WiFi Mesh coverage solutions can be deployed. The terminal is inexpensive, easy and quick to deploy, and can achieve latency control within 10ms, which is suitable for working conditions with many turning points. The MPP (Massively Parallel Processing) network is connected to the backbone ring network through wires, and is equipped with omnidirectional antennas and directional antennas. The omnidirectional antenna supports 5GHz for MPMesh networking, and the directional antenna supports 2.4GHz for directional coverage of lanes. The distance between wireless nodes is generally 100-120m. To ensure communication quality, it is not recommended to exceed 8 hops.

[0087] Figure 6 The present invention is a structural diagram of a wireless communication network system according to another embodiment of the present invention. Figure 6 and Figure 5 The difference is that in Figure 6 In the illustrated embodiment, the wireless communication network system further includes a resource scheduling controller 54 .

[0088] The resource scheduling controller 54 is configured to allocate a first bandwidth to the plurality of wireless access points 53 and allocate a first bandwidth to at least one second communication device ( Figure 6 (not shown) allocates a second bandwidth, wherein the first bandwidth is greater than the second bandwidth.

[0089] That is to say, when the engineering machinery located at the tunnel face 50 is in a working state, more bandwidth resources are allocated to the wireless access point 53 located at the tunnel face 50 to ensure the communication demand of the engineering machinery.

[0090] In some embodiments, the resource scheduling controller 54 is configured to allocate the reserved bandwidth resources to the multiple wireless access points 53 when a traffic peak of the construction machinery is detected.

[0091] It should be noted here that, in the case of a traffic peak in the construction machinery, the reserved bandwidth resources are allocated to the wireless access point 53 located at the tunnel face 50 to ensure the communication demand of the construction machinery.

[0092] In some embodiments, the resource scheduling controller 54 is configured to allocate a third bandwidth to the plurality of wireless access points 53 and allocate a third bandwidth to at least one second communication device ( Figure 6 A fourth bandwidth is allocated (not shown), wherein the third bandwidth is smaller than the fourth bandwidth.

[0093] That is to say, when the engineering machinery located at the tunnel face 50 is in a non-working state, that is, the communication demand of the engineering machinery is relatively small, in this case, more bandwidth resources are allocated to the second communication device located in the tunnel, thereby improving the network quality in the tunnel and providing efficient use of bandwidth resources.

[0094] In some embodiments, the system can provide an intuitive user interface that enables construction managers to monitor network status and resource allocation in real time and perform manual intervention when necessary. The user interface supports a variety of operations, including viewing, adjusting, and optimizing resource allocation.

[0095] By implementing the above embodiments of the present disclosure, the limitations of traditional communication methods in tunnels are effectively solved, uniform coverage of wireless signals in tunnels is achieved, communication blind spots are eliminated, and communication efficiency is significantly improved. At the same time, the intelligent scheduling system can dynamically adjust network resources according to the construction progress and machine position, improving the flexibility and safety of construction.

[0096] In some embodiments, the functional unit described above can be implemented as a general-purpose processor, a programmable logic controller (PLC), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component or any appropriate combination thereof for performing the functions described in the present disclosure.

[0097] A person skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0098] The description of the present disclosure is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the present disclosure to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present disclosure, and to enable those of ordinary skill in the art to understand the present disclosure and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A wireless communication network system, comprising: A first communication device is arranged outside the tunnel; At least one second communication device is arranged inside the tunnel, wherein the first communication device is communicatively connected to the at least one second communication device via an optical fiber, and the at least one second communication device is configured to receive a signal sent by the first communication device via the optical fiber and send the signal in the tunnel.

2. The network system according to claim 1, wherein: The first communication device is a baseband unit BBU; The second communication device is a radio remote unit RRU.

3. The network system according to claim 2, further comprising a leaky cable, wherein: The at least one RRU device is configured to feed the signal into the leaky cable so as to transmit the signal in the tunnel.

4. The network system according to claim 3, wherein: The at least one RRU device includes one RRU device.

5. The network system according to claim 4, wherein: In a case where the length of the tunnel is less than the single-side coverage distance of the RRU device, the RRU device is arranged at the entrance or exit of the tunnel.

6. The network system according to claim 4, wherein: When the length of the tunnel is less than the coverage distance of the RRU device and not less than the single-side coverage distance of the RRU device, the RRU device is arranged in the middle area of ​​the tunnel.

7. The network system according to claim 3, wherein: The at least one RRU device includes multiple RRU devices.

8. The network system according to claim 7, wherein: When the length of the tunnel is not less than the coverage distance of the RRU devices, the multiple RRU devices are arranged inside the tunnel, wherein the interval between two adjacent RRU devices is not greater than the coverage distance of the RRU devices.

9. The network system according to claim 3, further comprising: A special antenna is arranged at a turn in the tunnel, wherein the special antenna is electrically connected to the RRU device and is used to send the signal in the tunnel.

10. The network system according to claim 3, further comprising: A first directional antenna is arranged at the exit of the tunnel, wherein the first directional antenna is electrically connected to the RRU device and is used to send the signal to the outside of the tunnel.

11. The network system according to claim 10, further comprising: A second directional antenna is arranged at the entrance of the tunnel, wherein the second directional antenna is electrically connected to the RRU device and is used to send the signal to the outside of the tunnel.

12. The network system according to claim 1, wherein: The first communication device is a near-end device; The at least one second communication device is a remote device.

13. The network system according to claim 12, wherein: The remote unit is configured to receive the signal sent by the near-end unit through an optical fiber, and forward the signal in the tunnel through an antenna.

14. The network system according to claim 1, wherein: The optical fiber includes a low-smoke, halogen-free, flame-retardant optical cable.

15. The network system according to claim 14, wherein: A physical isolation device is provided between the optical fiber and the high-voltage cable in the tunnel to reduce the interference of the high-voltage cable on the optical fiber.

16. The network system according to any one of claims 1 to 15, further comprising: A plurality of wireless access points are arranged on the palm face, wherein the plurality of wireless access points are communicatively connected with the first communication device via optical fibers.

17. The network system according to claim 16, wherein: The wireless access point includes at least one of a pico base station or a WIFI access point.

18. The network system according to claim 16, further comprising: The resource scheduling controller is configured to allocate a first bandwidth to the multiple wireless access points and a second bandwidth to the at least one second communication device when the engineering machinery located at the tunnel face is in a working state, wherein the first bandwidth is greater than the second bandwidth.

19. The network system according to claim 18, wherein: The resource scheduling controller is configured to allocate the reserved bandwidth resources to the multiple wireless access points when a traffic peak occurs on the engineering machinery.

20. The network system according to claim 18, wherein: The resource scheduling controller is configured to allocate a third bandwidth to the multiple wireless access points and a fourth bandwidth to the at least one second communication device when the engineering machinery located at the tunnel face is in a non-working state, wherein the third bandwidth is smaller than the fourth bandwidth.

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