Wireless relay system, its base unit, and communication resource control method

Abstract

To further improve safety by making it possible to quickly secure communication resources in an emergency.SOLUTION: A wireless relay system according to an embodiment is a system that relays wireless band signals transmitted and received from base stations of a mobile communication system on a physical layer. The wireless relay system includes a base unit that sends and receives wireless band signals to and from the base station, and a plurality of slave units. The slave units are distributed in areas along roads where vehicles can travel. The base unit includes a communication portion and a resource allocation control portion. The communication unit communicates with a facility control center that controls road ancillary equipment. The resource allocation control portion varies the allocation of radio resources in the physical layer for each subordinate device on the basis of information notified from the facility control center.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a wireless relay system, a master unit thereof, and a communication resource control method. [Background technology]

[0002] Road transportation systems are an essential part of infrastructure in modern society. The environment surrounding transportation platforms is undergoing major changes due to factors such as the shift to EVs, the rise of self-driving vehicles, the rise of MaaS (Mobility as a Service), and the arrival of a super-aging society. In response to these changes, infrastructure operators are considering ways to improve the maintenance and operation management of facilities by incorporating new technologies. For example, maintaining the safety and security of tunnels is an important issue for control systems that manage expressway infrastructure, as accidents and disasters in long tunnels can affect many lives and are one of the events that managers must be most wary of.

[0003] Meanwhile, mobile communication systems are also an essential infrastructure in modern society. Wireless relay systems play a role in expanding service areas. This system, also known as DAS (Distributed Antenna System), remotely relays the wireless zone of a base station at the physical layer, and has become widely known since the launch of 5G (fifth generation mobile communication system) services. A wireless relay system comprises a master unit connected to a base station and remote units connected to the master unit via optical fiber. For example, by placing the remote units along the inside of a tunnel, mobile communication services can be provided even inside the tunnel where radio waves from outside cannot reach. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6652667 [Patent Document 2] Japanese Patent Application Publication No. 2018-124638 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-252365 [Patent Document 4] Japanese Patent Application Laid-Open No. 2005-244873 Summary of the Invention [Problem to be solved by the invention]

[0005] In the event of an emergency such as an accident or disaster, it is desirable to immediately stop vehicles traveling on the section of the tunnel near the entrance of the disaster area, and to assist vehicles traveling on the section of the tunnel near the exit in evacuating quickly. The key to this is the communications environment. In order to enable rescue and recovery vehicles to work safely inside the tunnel, it is necessary to establish and maintain a communications environment as early as possible after a disaster occurs. However, especially in the entrance section, communication requests are concentrated, and in severe cases congestion may occur, causing communication to become impossible. As this could be a life-threatening situation, some kind of technological innovation is required.

[0006] Therefore, an object of the present invention is to provide a radio relay system and its master unit, and a communication resource control method that can quickly secure communication resources in an emergency and further improve safety. [Means for solving the problem]

[0007] According to an embodiment, the wireless relay system is a system that relays wireless band signals transmitted and received from a base station of a mobile communication system at a physical layer. The wireless relay system includes a base station that transmits and receives wireless band signals to and from the base station, and multiple slave stations. The slave stations are distributed in areas along roads on which vehicles can travel, and establish wireless zones. The base station includes a communication unit and a resource allocation control unit. The communication unit communicates with a facilities control center that controls roadside facilities. The resource allocation control unit identifies a disaster location within the area based on information notified from the facilities control center, and varies the allocation of wireless resources to each slave station under its control based on the relationship between the disaster location and the vehicle's traveling direction. Each slave station includes a wireless zone formation unit and a wireless connection unit. The wireless zone formation unit establishes a wireless zone using the wireless resources allocated by the base station. The wireless connection unit wirelessly connects to mobile stations present in the wireless zone. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a system diagram showing an example of a wireless relay system according to an embodiment. [Figure 2] 2 is a system diagram showing cooperation between the wireless relay system shown in FIG. 1 and a facility control center 400. [Figure 3] 2 is a functional block diagram showing an example of a parent device 100 and child devices 301 to 30n. [Figure 4] 3 is a functional block diagram showing an example of the central processing unit 500 and the monitor control console 700 shown in FIG. 2. [Figure 5] FIG. 8 is a diagram showing an example of data managed in a database 800. [Figure 6] FIG. 4 is a sequence diagram showing an example of a processing procedure according to the embodiment. [Figure 7] FIG. 10 is a diagram showing an example of radio resource allocation in normal times. [Figure 8] FIG. 10 is a diagram showing an example of radio resource allocation in normal times. [Figure 9] FIG. 10 is a diagram showing an example of wireless resource allocation when a fire occurs. [Figure 10]FIG. 10 is a diagram showing an example of wireless resource allocation when a fire occurs. DETAILED DESCRIPTION OF THE INVENTION

[0009] (composition) FIG. 1 is a system diagram showing an example of a wireless relay system according to an embodiment. This system, known as a Distributed Antenna System (DAS), extends the wireless zone of a base station of a mobile communication system by using optical fiber communication. That is, the DAS relays radio band signals from the base station of the mobile communication system at the physical layer. The DAS can efficiently cover areas with long, narrow spaces, such as the land used by expressway companies or railway operators.

[0010] 1, a facility control center 400 is a control center that manages road facilities. In addition, fire detectors 4 that detect the occurrence of a fire and cameras that capture images inside the tunnel are also installed, for example, at equal intervals inside the tunnel. Furthermore, the DAS system includes a base station 200, a base station 100, and a plurality of slave stations 301 to 30n. The base station 100 connected to the base station 200 accommodates the plurality of slave stations 301 to 30n via optical fiber. The slave stations 301 to 30n are distributed along roads on which vehicles can travel. In the embodiment, it is assumed that the slave stations 301 to 30n are arranged along the inside of a tunnel on a highway.

[0011] The base station 100 can control the operations of the mobile stations 301 to 30n, such as turning radio wave output on / off. Based on the control from the base station 100, the mobile stations 301 to 30n transmit and receive radio band signals in the air interface section of the mobile communication system in both uplink and downlink (UL / DL) directions. That is, the mobile stations 301 to 30n each deploy a radio zone. The radio zones of the mobile stations 301 to 30n are combined to form a DAS service area that covers the inside of a tunnel. This makes it possible to deploy mobile communication services even in environments where radio waves from outside are difficult to reach, such as inside a tunnel. A mobile terminal carried by a passenger in the vehicle 3 can communicate with the Internet or the like from any of the slave units 301 to 30n via the master unit 100 and the base station 200. The master unit 100 communicates with a facility control center 400 that controls road incidental facilities on the road via an IP (Internet Protocol) network 1, and can exchange information with the facility control center 400.

[0012] 2 is a system diagram showing the cooperation between the wireless relay system shown in FIG. 1 and the facility control center 400. By physically connecting the IP network 1 and the parent device 100 of the wireless relay system (DAS) via an IP interface, it is possible to cooperate with each other.

[0013] In Fig. 2, when a fire detector 4 detects a fire in a tunnel, it generates a fire detection signal. This fire detection signal is received by a remote monitoring and control device (hereinafter referred to as an information hub) 6, which centrally manages the ancillary facilities in the tunnel. The information hub 6 digitizes the fire detection signal, places it in an IP packet, and transmits it to a central processing unit 500 in a facility control center 400 via an IP network 1.

[0014] Not only the fire detectors 4, but also the cameras 5 and the tunnel information boards 2 installed at the tunnel entrances are connected to the information hub 6. These are interconnected, for example, via Ethernet (registered trademark). Information about the inside of the tunnel, including video data and fire detection signals from the cameras 5, is transmitted to the facility control center 400 via the information hub 6. In addition, device control information transmitted from the facility control center 400 is transmitted to the destination devices via the information hub 6.

[0015] The facility control center 400 comprises a central processing unit 500, a large display 600, and a monitoring control console 700. The central processing unit 500 displays the operating status of the ancillary equipment inside the tunnel (fire detectors 4, cameras 5, etc.) on the display 600, and notifies the monitoring control console 700 of any abnormalities in the equipment inside the tunnel. This allows various types of information to be communicated to the controller at the facility control center 400.

[0016] Controllers constantly maintain and manage the operation of the expressway while referring to the information displayed on the screen of the display 600. For example, if a fire breaks out in a tunnel, the controller checks the images from the camera 5, etc., to confirm that a fire has definitely occurred and identify the location of the fire. The controller then operates the monitoring control console 700 to select a message to be displayed on the tunnel information board 2 and requests the central processing unit 500 to transmit the message. Based on instructions from the monitoring control console 700, the central processing unit 500 displays a message on the tunnel information board 2 via the information hub 6 of the relevant tunnel.

[0017] 3 is a functional block diagram showing an example of the parent device 100 and the child devices 301 to 30n. First, the parent device 100 will be described. The base station 100 includes a signal processing unit 110, a demultiplexing unit 130, a processor 140, a memory 150, a base station interface 160, a network interface 170, and a handset interface 180. In other words, the base station 100 is a computer including a processor and a memory.

[0018] The base station interface 160 is connected to the base station 200 via, for example, a coaxial cable. The network interface 170 is connected to the IP network 1. The slave interface 180 is connected to subordinate slaves 301 to 30n via optical fibers.

[0019] The signal processing unit 110 exchanges uplink / downlink (UL / DL) signals with the base station 200 via the base station interface 160 . The demultiplexer 130 converts the DL signal from the signal processing unit 110 into an optical signal, then wavelength-multiplexes it for each carrier and transmits it to the slave units 301 to 30n from the slave unit interface 180 via optical fiber. The demultiplexer 130 also separates the optical signals arriving from the slave units 301 to 30n via optical fiber into electrical signals and extracts digital signals. These digital signals are sent to the signal processing unit 110.

[0020] The signal processing unit 110 includes a transmit / receive switch (SW) 111, an A / D converter (ADC) 113, and a D / A converter (DAC) 116. The transmit / receive switch 111 switches the UL / DL switching timing with the opposing base station 200 in synchronization with the UL / DL switching timing provided by the processor 140. This realizes communication by TDD (Time Division Duplex).

[0021] In the downlink, a carrier band signal from the opposing base station 200 is sent to the A / D converter 113 of the signal processing unit 110. The A / D converter 113 converts this carrier band signal into a digital signal and sends it to the demultiplexing unit 130. The demultiplexing unit 130 converts the digital signal from the signal processing unit 110 into an optical signal, then wavelength-multiplexes it with other wavelengths and transmits it from the slave interface to the slave units 301 to 30n via optical fiber.

[0022] On the other hand, in the uplink, the digital signal from the demultiplexer 130 is input to a D / A converter (DAC) 116 of the signal processor 110. The D / A converter 116 converts the digital signal to an analog signal and upconverts it to the carrier band to reproduce a UL signal. This UL signal is transmitted to the base station 200 via the transmit / receive switch 111 and the coaxial cable.

[0023] The processor 140 of the base unit 100 includes an IP communication unit 140a and a resource allocation control unit 140b as processing functions according to the embodiment.

[0024] The IP communication unit 140 a communicates with the facility control center 400 via the IP network 1 . The resource allocation control unit 140b changes the allocation of wireless resources to the subordinate slave units 301 to 30n for each slave unit based on information notified from the facility control center 400. That is, the resource allocation control unit 140b changes the allocation of communication resources in the physical layer between the slave units and the mobile terminal.

[0025] The memory 150 is a nonvolatile memory such as a flash memory, and stores disaster location information 150a and slave unit position information 150b. The disaster location information 150a is information that indicates the location of the disaster location and is included in information notified from the facility control center 400.

[0026] The slave device position information 150b is information indicating the position information of the subordinate slave devices 301 to 30n within the tunnel (service area). By referring to the disaster location information 150a and the slave device position information 150b, the positional relationship between the disaster location and each of the slave devices 301 to 30n can be identified.

[0027] Next, the slave units 301 to 30n will be described. Each of the slave units 301 to 30n includes an antenna 27, a demultiplexer 21, a processor 22, a delay adjuster 23, a D / A converter (DAC) 24, a transmit / receive switch (SW) 25, and an A / D converter (ADC) .

[0028] The demultiplexer 21 separates the optical signal from the base station 100 into individual wavelengths, converts the optical signal into an electrical signal, and extracts a digital DL signal. The processor 22 detects the delay adjustment amount via the DL signal from the processor 140 of the base station 100, and outputs the amount to the delay adjustment unit 23. The delay adjustment unit 23 delays the transmission timing of the DL signal based on the delay adjustment amount from the processor 22. This allows the master device 100 and the slave devices 301 to 30n to be synchronized with each other.

[0029] The delay-controlled DL signal is output to a D / A converter 24. The D / A converter 24 converts the DL signal into an analog signal and upconverts it to the band of the assigned channel. This DL signal in the radio band is radiated into the air via a transmit / receive switch 25 and an antenna 27 and is received by a mobile terminal (not shown).

[0030] The UL signal that reaches the slave device 301 is sent from the antenna 27 to the A / D converter 26 via the transmit / receive switch 25. The A / D converter 26 down-converts the UL signal from the mobile terminal to baseband, then converts it to digital, and outputs the digital signal to the demultiplexer 21. The demultiplexer 21 converts the digital signal into an optical signal, then multiplexes it, and transmits it to the master device 100 via optical fiber.

[0031] The processor 22 of each of the slave units 301 to 30n includes a wireless zone forming unit 22a and a wireless connection unit 22b.

[0032] The wireless zone forming unit 22a forms its own wireless zone using the wireless resources allocated by the master unit 100. The wireless connection unit 22b wirelessly connects to mobile stations located within its own wireless zone.

[0033] Fig. 4 is a functional block diagram showing an example of the central processing unit 500 and the monitoring control console 700 shown in Fig. 2. The central processing unit 500 includes an IP data transmitting / receiving unit 51, a receiving processing unit 52, a display unit 53, a status determining unit 54, and a transmitting processing unit 55.

[0034] The transmission processing unit 55 passes data acquired from the database 800 and data passed from the monitoring control console 700 to the IP data transmission / reception unit 51. The IP data transmission / reception unit 51 converts the acquired data into IP packets and sends them to the IP network 1, and also extracts data from the IP packets that arrive via the IP network 1. Here, the data acquired from the IP network 1 includes, for example, data detected by the fire detector 4.

[0035] The receiving processing unit 52 stores the data passed from the IP data transmitting / receiving unit 51 in the database 800, or transmits it to the display unit 53. The display unit 53 visualizes the data passed from the receiving processing unit 52 and displays it on the display 600.

[0036] The situation determination unit 54 decodes the data passed from the reception processing unit 52 and determines whether a fire has broken out in the tunnel, for example, based on the detection data of the fire detector 4. If it determines that a fire has broken out in the tunnel, the situation determination unit 54 references the information held in the database 800 to create information for notifying the base unit 100, and passes this information to the transmission processing unit 55. This information is sent to the IP network 1 via the transmission processing unit 55 and the IP data transmission / reception unit 51, and is delivered to the destination base unit 100.

[0037] The monitoring control console 700 comprises a tunnel information display unit 71 , a monitor 72 , an operation unit 73 , a data creation unit 74 , and a database 75 . The tunnel information display unit 71 displays on the monitor 72, for example, real-time images from the camera 5 sent from the central processing unit 500. This allows the controller to visually check the status of the roadside facilities inside the tunnel, and prevents the issuance of an alarm due to a malfunction of the fire detector 4. Furthermore, if the controller confirms through visual check that there is actually a fire, he or she operates the operation unit 73 to display, for example, a message on a tunnel information board to call attention to the situation.

[0038] The database 75 stores, for example, a message template 75a for when there is a traffic jam or a message template 75b for when a fire has broken out. The controller operates the operation unit 73 to select a message according to the status of the roadside equipment. The data creation unit 74 creates control data based on the selected message and passes it to the transmission processing unit 55 of the central processing unit 500. The transmission processing unit 55 processes the control data and passes it to the IP data transmission / reception unit 51, which then converts the control data into IP packets and sends them to the IP network 1.

[0039] The database 800 accessible from the central processing unit 500 is a database for monitoring road incidental facilities in tunnels and managing the acquired status.

[0040] 5 is a diagram showing an example of data managed in database 800. Database 800 manages tunnel identification codes 81, a fire detector management table 82, a slave unit management table 83, a fire situation management table 84, a camera management table 85, and an information board management table 86.

[0041] The tunnel identification code 81 is code information for uniquely identifying a tunnel to be monitored. The tunnel identification code 81 enables the system to identify, for example, the location of the tunnel. The fire detector management table 82 is a table for managing each fire detector 4 (FIG. 2) by associating it with the identification information of the slave unit located in the direction of the tunnel exit. The fire detector management table 82 stores, for example, the identifier code of the slave unit that stops (shuts off) radio wave output when the fire detector 4 detects a fire. In this embodiment, each fire detector 4 is associated with the identification code of the slave unit installed in the direction of the tunnel exit from the location of the fire detector 4.

[0042] The slave unit management table 83 is a table for managing each of the slave units 301 to 30n in association with its operating status. The fire situation management table 84 is a table for managing information (fire situation) indicating whether a fire has been detected by each fire detector 4 (FIG. 2) in association with each other.

[0043] The camera management table 85 is a table for managing each camera 5 in association with its current status. The information board management table 86 is a table for managing each tunnel information board 2 (FIG. 2) in association with its current display content (display state).

[0044] (action) Next, the operation of the above configuration will be described. FIG. 6 is a sequence diagram illustrating an example of a processing procedure according to the embodiment. When a fire is detected by any of the fire detectors 4 (step S1), the fire detector 4 issues fire detection information. This fire detection information is notified to the central processing unit 500 of the facility control center 400 from the information hub 6 via the IP network 1.

[0045] Upon receiving the fire detection information, the central processing unit 500 registers the fire situation in the fire situation management table 84 of the database 800, and also displays the tunnel in which the fire was notified and the location of the fire on the display 600. Furthermore, the central processing unit 500 waits for confirmation by the controller (step S3). The controller checks the images from each camera 5 displayed on the display 600, and if the controller does not find any images that support the occurrence of a fire, the controller determines that the alarm is a false alarm (Yes) and the system returns to the idle state (step S4).

[0046] If flames or smoke caused by a fire are visible, the controller confirms that it is not a false alarm (No) and operates the operation unit 73 (Fig. 2) to select the content to be displayed on the tunnel information board. In this case, the message "Tunnel Fire Occurred" is selected. This message is sent from the central processing unit 500 via the IP network 1 and information hub 6 to the tunnel information board 2, where it is displayed.

[0047] Furthermore, the central processing unit 500 transmits disaster location information indicating the location of the disaster location to the parent device 100 via the IP network 1 (step S5). The master device 100 receives the disaster location information, stores the information in the memory 150 (disaster location information 150a), and identifies the slave device that should stop transmitting (step S6). Here, the resource allocation control unit 140b (FIG. 3) of the master device 100 identifies the slave device that should stop transmitting based on the disaster location and the location information of the slave devices 301 to 30n.

[0048] The resource allocation control unit 140b stops radio waves from the slave units located ahead of the disaster location in the traveling direction of the vehicle, and then reallocates the radio resources remaining due to the radio waves being stopped to the slave units located behind the disaster location in the traveling direction.

[0049] For example, if a fire breaks out between slave units 301 and 302, resource allocation control unit 140b recalculates the allocation of resources to each of slave units 301 to 303 (step S7) and sends a resource resetting request based on the results to slave units 301 to 303. Receiving this, the slave unit 301 resets the time slot schedule in its own wireless zone (step S8). Then, both the slave units 302 and 303 stop transmitting (steps S9 and S10).

[0050] Here, examples of the wireless resources include a plurality of time slots that are time-division multiplexed, a plurality of frequency bands that are frequency-multiplexed, etc. In the embodiment, the time slots will be described as an example.

[0051] 7 and 8 are diagrams showing an example of radio resource allocation in normal times. As shown in Fig. 7, under normal circumstances, radio resources are allocated roughly equally to mobile devices 301 to 303 in a service area. Suppose seven vehicles 3a to 3g are present in the service area. Then, as shown in Fig. 8, slot τ1 is allocated to vehicle 3a, slot τ2 to vehicle 3b, ..., slot τ7 to vehicle 3g. Conventionally, this allocation is fixed, and in the event of a fire, radio resources are allocated to mobile devices that do not require allocation.

[0052] In contrast to this, in the embodiment, if a fire breaks out between slave units 301 and 302 in the state shown in FIGS. 7 and 8, the time slot allocation is dynamically changed. 9 and 10 are diagrams showing an example of wireless resource allocation when a fire occurs. As shown in Figure 9, when a fire breaks out between slave units 301 and 302, slave units 302 and 303 stop transmitting. As a result, the remaining time slots are reallocated to slave unit 301, and as shown in Figure 10, communication with vehicles 3a, 3b, and 3c is repeated in slots from τ4 onwards. This allows vehicles 3a, 3b, and 3c to expand their communication bands compared to before the fire broke out, making it possible to quickly obtain necessary information.

[0053] (effect) As described above, in this embodiment, when a fire is detected by the fire detector 4, the facility control center 400 notifies the DAS master unit 100 of disaster location information. Upon receiving this, the master unit 100 stops transmitting signals from the slave units ahead of the disaster location and reallocates the corresponding communication resources to the remaining slave units.

[0054] When a fire breaks out, it is necessary to send an emergency stop message to vehicles traveling in the section before the fire site, and to support vehicles traveling after the fire site in quickly evacuating from the tunnel. However, with existing technology, while information is provided to people through displays such as road information boards, it cannot be said that information is provided sufficiently to the information and communications infrastructure. It is necessary to quickly establish and maintain a communications environment inside the tunnel so that rescue and recovery vehicles can work safely inside the tunnel. However, with existing technology, it is difficult to maintain a communications environment in necessary locations, such as around the fire site.

[0055] In contrast, in this embodiment, fire information is provided to a wireless relay system installed as a communications infrastructure within the tunnel, and the service area is dynamically changed. That is, the facility control center 400 obtains information on the location of the disaster from road tunnel emergency facilities (fire detectors 4, cameras 5, etc.), and controls the radio wave emissions of the DAS slave units accordingly, thereby making only a specific section within the tunnel the service area. In other words, by limiting the communicable section and narrowing down the terminals that can communicate, the bandwidth of each communication in the remaining area can be expanded and stabilized.

[0056] If a fire breaks out inside a tunnel, it is possible to maintain the communication environment from the fire source to the tunnel entrance by stopping the radio wave output of the slave units in the direction of the tunnel exit. In other words, by stopping the radio wave output of the slave units, it is possible to allocate wireless resources to the necessary areas.

[0057] As a result, according to the embodiment, communication resources can be quickly secured in an emergency, thereby making it possible to provide a wireless relay system, its parent unit, and a communication resource control method that further improve safety.

[0058] The present invention is not limited to the above-described embodiment. For example, in the embodiment, the mobile terminals ahead of the disaster location are stopped from transmitting, but this is not necessarily required. It is also possible to reserve time slots to leave even a small amount of room for communication without stopping transmission. In short, by dynamically changing the allocation of wireless resources for each mobile terminal based on the relationship between the disaster location and the direction of travel of the vehicle, it becomes possible to quickly secure communication resources in an emergency.

[0059] 1, infrastructure sharing may be applied so that base stations of different carriers (business entities) can be accommodated in the base station 100. This type of base station is also called a multi-carrier device.

[0060] DAS can also be applied to local 5G areas. Local 5G is a system that allows licensees to provide mobile communication services in their own areas. Local 5G allows quasi-synchronous operation or asynchronous operation using TDD (Time Division Duplex). The technology of the embodiments can also be applied to this type of system.

[0061] Furthermore, for example, the communication resources redistributed to the slave devices whose transmissions have not been stopped are not limited to time slots, but may be frequency or wavelength resources. Furthermore, so-called resource units, which are defined by frequency and time slots, may be redistributed.

[0062] In the embodiment, the master unit 100 takes the initiative in determining which slave units should stop transmitting and reallocating resources. Alternatively, the central processing unit 500 of the facility control center 400 may take the initiative in performing necessary control. For example, since the fire detector management table 82 is stored in the database 800 of Fig. 5, it is possible for the central processing unit 500 to identify which slave units should stop transmitting.

[0063] Therefore, when the fire detector 4 notifies the occurrence of a fire, the central processing unit 500 may automatically shut down the slave units on the exit side from the fire and reallocate wireless resources to the slave units on the entrance side.

[0064] When the central processing unit 500 detects a fire, it determines which slave unit to stop from information obtained from the database 800, and instructs the master unit 100 to stop transmitting from that slave unit. In response to this, the master unit 100 stops transmitting from the corresponding slave unit. This makes it possible to maintain the communication environment around the tunnel fire.

[0065] However, if the controller confirms that the fire notification from the fire detector 4 is a false alarm, the controller immediately sends a request to start the slave units to the central processing unit 500. Upon receiving this, the central processing unit 500 immediately restarts the slave units that have stopped transmitting and controls the redistributed radio resources to be restored. In this way, even if the slave units are automatically stopped when the fire notification is a false alarm, the slave units can be reliably restored by manual operation by an operator.

[0066] Although an embodiment has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. This novel embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. This embodiment and its modifications are included within the scope and spirit of the invention, and are also included in the inventions described in the claims and their equivalents. [Explanation of symbols]

[0067] 1...IP network, 2...tunnel information board, 3 (3a to 3g)...vehicle, 4...fire detector, 5...camera, 6...information hub, 21...multiplexing / demultiplexing unit, 22...processor, 22a...wireless zone formation unit, 22b...wireless connection unit, 23...delay adjustment unit, 24...D / A converter, 25...transmission / reception switch, 26...A / D converter, 27...antenna, 51...IP data transmission / reception unit, 52...reception processing unit, 53...display unit, 54...situation determination unit, 55...transmission processing unit, 60...display, 71...tunnel information display unit, 72...monitor, 73...operation unit, 74...data creation unit, 75...database, 75a...traffic jam message template, 75b...fire message template, 81...tunnel identification code, 82...fire Detector management table, 83...slave unit management table, 84...fire situation management table, 85...camera management table, 86...information board management table, 100...parent unit, 110...signal processing unit, 111...transmit / receive switch, 113...A / D converter, 116...D / A converter, 130...multiplexing / demultiplexing unit, 140...processor, 140a...IP communication unit, 140b...control unit, 150...memory, 150a...disaster location information, 150b...slave unit location information, 160...base station interface, 170...network interface, 180...slave unit interface, 200...base station, 301 to 30n...slave units, 400...facility control center, 500...central processing unit, 600...display, 700...monitoring control console, 800...database.

Claims

1. In a wireless relay system that relays wireless band signals transmitted and received from a base station of a mobile communication system at a physical layer, a master unit that transmits and receives the radio band signal to and from the base station; a plurality of slave units that are distributed in an area along a road on which vehicles can travel and that develop wireless zones; The parent device is a communication unit that communicates with a facility control center that controls road incidental facilities of the road; a resource allocation control unit that identifies a disaster location within the area based on information notified from the facility control center, and varies allocation of wireless resources for each slave unit under its control based on a relationship between the disaster location and the traveling direction of the vehicle, Each of the slave units a wireless zone forming unit that deploys the wireless zone using wireless resources allocated by the master unit; a wireless connection unit for wirelessly connecting with a mobile station located within the wireless zone;

2. the resource allocation control unit stops radio waves from a slave unit located ahead of the disaster location in the traveling direction, and reallocates the radio resources to a slave unit located behind the disaster location in the traveling direction. The wireless relay system according to claim 1 .

3. the master device further includes a storage unit configured to store location information of subordinate slave devices in the area; the resource allocation control unit identifies the slave device to be stopped from transmitting based on the location of the disaster and the location information of the slave device under control; The wireless relay system according to claim 2 .

4. In a base station of a wireless relay system that relays wireless band signals transmitted and received from a base station of a mobile communication system at a physical layer, a slave interface that accommodates a plurality of slave units that are distributed in an area along a road on which vehicles can travel, each of which deploys a wireless zone; a communication unit that communicates with a facility control center that controls road incidental facilities; a base unit that identifies a disaster location within the area based on information notified from the facility control center, and that varies the allocation of wireless resources to each subordinate slave unit based on the relationship between the disaster location and the direction of travel of the vehicle.

5. A communication resource control method for a wireless relay system that includes a base station for transmitting and receiving wireless band signals to and from a base station of a mobile communication system, and a plurality of slave stations that are distributed in an area along a road on which vehicles can travel and that establish wireless zones, and that relays the wireless band signals at a physical layer, comprising: a step in which the master unit identifies a disaster location within the area based on information notified from a facility control center that controls road facilities on the road, and varies allocation of wireless resources to each slave unit under its control based on a relationship between the disaster location and the traveling direction of the vehicle; and a step in which each of the slave units deploys the wireless zone using the wireless resources allocated by the master unit. A method for controlling communication resources.

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