Communication systems and information processing equipment

Abstract

This technology provides the ability to deliver information even to fixed terminals in areas where delivery is currently impossible. [Solution] The communication system comprises a plurality of fixed terminals capable of communicating with other fixed terminals located within a first distance from itself, a mobile terminal capable of wireless communication with the fixed terminals within a second distance, distribution means for distributing information to at least one of the plurality of fixed terminals, and control means for controlling the mobile terminal so that the information is transmitted to a fixed terminal among the plurality of fixed terminals if there is a fixed terminal among the plurality of fixed terminals that has not received the information from the other fixed terminals.

Description

Technical Field

[0001] The present invention relates to a communication system and an information processing apparatus.

Background Art

[0002] Techniques for transmitting data from a base station to a mobile body are known. For example, Patent Document 1 discloses a system for distributing data from a data base station arranged along a moving route of a train to a terminal in the mobile body. This technique assumes that the communication network on the infrastructure side is normal.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a communication network between fixed terminals, an unreachable area where information cannot be reached may occur due to a communication failure or the like. In this case, unless the communication failure or the like is resolved, it becomes difficult to transmit information to the fixed terminals in the unreachable area. Further, when constructing a communication network between fixed terminals by short-range wireless communication, the communication network may be divided into a plurality of physically or communication-topologically separated areas, and some of the areas may become unreachable areas.

[0005] The present disclosure provides a technique capable of delivering information to fixed terminals in an unreachable area.

Means for Solving the Problems

[0006] One aspect of the present disclosure provides a communication system comprising: a plurality of fixed terminals capable of communicating with other fixed terminals located within a first distance from itself; a mobile terminal capable of wireless communication with the fixed terminals within a second distance; distribution means for distributing information to at least one of the plurality of fixed terminals; and control means for controlling the communication operation of the mobile terminal so that, if there is a fixed terminal among the plurality of fixed terminals that has not received the information from the other fixed terminals, the information is transmitted to that fixed terminal.

[0007] The aforementioned fixed terminal may maintain status information indicating the update status of the information or its own communication status. The mobile terminal obtains the status information from the fixed terminal. The mobile terminal may determine, based on the status information, whether the fixed terminal is an unupdated terminal or a terminal unable to communicate.

[0008] The aforementioned fixed terminal may autonomously form or update communication groups depending on the status of other fixed terminals with which it can communicate. The mobile terminal moves between multiple communication groups. In this process, the mobile terminal may distribute or synchronize information held by one communication group to other communication groups.

[0009] In a communication group of fixed terminals that extends over a wider area than the first distance, information may be propagated by a bucket brigade method in which each fixed terminal successively transfers the information it receives to other fixed terminals within the first distance. The fixed terminal may hold or display at least one of the following as information: operation information, congestion information, local information, and commercial information. The fixed terminal may be installed at a bus stop, and the mobile terminal may be installed on a bus vehicle.

[0010] Another aspect of the present disclosure provides an information processing device comprising: management means for managing the distribution status of information to a plurality of fixed terminals capable of communicating with other fixed terminals located within a first distance from itself; distribution means for distributing the information to at least one of the plurality of fixed terminals; and control means for controlling the communication operation of a mobile terminal capable of wireless communication with a fixed terminal within a second distance so that, if there is a fixed terminal among the plurality of fixed terminals that has not received the information from the other fixed terminals, the information is transmitted to that fixed terminal. [Effects of the Invention]

[0011] According to the present invention, information can be delivered even to fixed terminals in areas where delivery is impossible. [Brief explanation of the drawing]

[0012] [Figure 1] A diagram illustrating the overall configuration of the communication system according to this embodiment. [Figure 2] A diagram illustrating the functional configuration of a communication system. [Figure 3] A diagram illustrating the hardware configuration of the management server. [Figure 4] A diagram illustrating the hardware configuration of a mobile terminal. [Figure 5] A diagram illustrating the hardware configuration of a fixed terminal. [Figure 6] A diagram illustrating multiple clusters. [Figure 7] A diagram illustrating countermeasures for communication interruptions within a cluster. [Figure 8] A diagram illustrating the data distribution sequence using fixed terminals within a cluster. [Figure 9] A diagram illustrating the data structure of the fixed terminal management table. [Figure 10] A diagram illustrating the control processing flow for data distribution by mobile terminals. [Figure 11] A diagram illustrating the data structure of a data package. [Figure 12] A diagram illustrating a data transfer sequence using a mobile terminal. [Figure 13]A diagram illustrating a detailed sequence in data synchronization processing between a mobile terminal and a fixed terminal.

Embodiments for Carrying Out the Invention

[0013] FIG. 1 is a diagram illustrating the overall configuration of a communication system 1 according to this embodiment. The communication system 1 according to this embodiment is a system for distributing information within a predetermined area, and is operated by, for example, a bus operating company or the like. The communication system 1 includes a base 50, a management server 10, a mobile body 40, a mobile terminal 20, and a plurality of fixed terminals 30. The base 50 is a facility such as an office. The management server 10 is an information processing device installed at the base 50 and manages the information to be distributed to each terminal. The mobile body 40 is a vehicle such as a bus that moves within the area. The mobile terminal 20 is an information terminal mounted on the mobile body 40 and capable of wireless communication. The fixed terminal 30 is an information terminal capable of wireless communication installed at various locations within the area, and is incorporated into infrastructure facilities such as bus stops.

[0014] Multiple fixed terminals 30 form a cluster 300 as a communication group. Multiple fixed terminals 30 may autonomously form or update the cluster 300. For example, the cluster 300 is formed or updated by each fixed terminal 30 periodically searching for nearby, communicable fixed terminals 30 and registering communication partners. The cluster 300 includes fixed terminals 30a located within the wireless communication range of the management server 10 and capable of direct communication, and fixed terminals 30b that do not communicate directly with the management server 10. Fixed terminals 30a capable of direct communication with the management server 10 may be referred to as "master terminals" below, and fixed terminals 30b that do not communicate directly with the management server 10 may be referred to as "slave terminals" below. However, the terms "master terminal" and "slave terminal" refer to differences in roles due to their positional relationship with the management server 10, and the devices themselves may be equivalent in terms of hardware and software. When the master fixed terminal 30a receives information distributed from the management server 10, it forwards the information to a slave fixed terminal 30b located within its communication range (i.e., within a first distance from itself). The slave fixed terminal 30b then forwards the received information to another fixed terminal 30b located within its communication range (i.e., within a first distance from itself). In this way, multiple fixed terminals 30 can share information within the cluster 300 using a bucket brigade method or the like. This ensures that information is distributed even to fixed terminals 30b that cannot communicate directly with the management server 10. In this specification, direct transmission of information from the management server 10 to the fixed terminals 30 is referred to as "distribution," while direct or indirect delivery of information to the fixed terminals 30 is referred to as "distribution."

[0015] The communication system 1 can distribute information using the mobile body 40 equipped with the mobile terminal 20. That is, the mobile body 40 is moving along a predetermined route, and the mobile terminal 20 holds the data acquired from the management server 10. When the mobile terminal 20 approaches any one of the fixed terminals 30 as the mobile body 40 moves (i.e., gets closer within a second distance from itself; the speed of the mobile body 40 at the time of approach is not limited), the mobile terminal 20 can perform wireless communication with the fixed terminal 30 and transfer the information to the fixed terminal 30. Therefore, since the fixed terminal 30 can also receive information via the mobile terminal 20, the mobile body 40 and the mobile terminal 20 function as a physical data carrier so as to complement the communication network between the fixed terminals 30.

[0016] FIG. 2 is a diagram illustrating the functional configuration of the communication system 1. As described above, the communication system 1 according to the present embodiment includes the management server 10, the mobile terminal 20, and the fixed terminal 30. The management server 10 includes a storage unit 11, a communication unit 12, a management unit 13, and a control unit 14. In the storage unit 11, for example, a fixed terminal management table 111 and a distribution data DB 112 are stored.

[0017] The fixed terminal management table 111 is a data table for managing the states of each fixed terminal 30 included in the communication system 1, and the management server 10 can grasp the network topology of the entire system and the reachability of information. The distribution data DB 112 is a database that accumulates content data (distribution data) representing the information to be distributed to each fixed terminal 30. The content data can include, for example, timetable data of transportation means such as buses, notification data regarding operation status and congestion status (operation information and congestion information), information such as regional events (regional information), and advertisement data (commercial information).

[0018] The communication unit 12 is a means for performing short-range wireless communication such as Wi-Fi HaLow (IEEE 802.11ah), for example, and can communicate with the fixed terminal 30 and the mobile terminal 20 within the communication range. The communication unit 12 functions as a distribution means for distributing information to at least one of the plurality of fixed terminals 30.

[0019] The management means 13 manages the information distribution status for each of the multiple fixed terminals 30, the communication status of each fixed terminal 30, etc., using the fixed terminal management table 111. The management means 13 can obtain status information for each fixed terminal 30 by communication via the base station of the fixed terminals 30, or by retrieving patrol logs collected and brought back by the mobile terminals 20.

[0020] The control means 14 controls the overall operation of the management server 10. The control means 14 also controls the mobile terminal 20 for the physical delivery of information to fixed terminals 30 that have not received information. Fixed terminals 30 that have not received information include, for example, unupdated terminals whose data has not been updated, and uncommunicated terminals that are unable to communicate due to a disconnection of the communication network. Control of the mobile terminal 20 includes controlling the operation of the mobile terminal 20 by sending instructions to the mobile terminal 20.

[0021] The mobile terminal 20 includes a storage means 21, a communication means 22, a control means 23, and a positioning means 24. The storage means 21 stores data handled by the mobile terminal 20 and stores distribution data received from the management server 10. The storage means 21 also stores log data collected from the fixed terminal 30. The storage means 21 functions as a buffer until the mobile terminal 20 enters the wireless communication range of the management server 10 and uploads the log data to the management server 10.

[0022] The communication means 22 can perform wireless communication with the management server 10 and with the fixed terminal 30, for example, using the IEEE 802.11ah standard. The communication range of the communication means 22 is, for example, within a second distance less than or equal to a first distance. The communication means 22 has sufficient communication performance (communication speed and connectivity) to enable passing communication with the fixed terminal 30 even when the mobile unit 40 is moving. This ensures a stable communication path even in places with poor line of sight or while moving. The relative magnitudes and absolute values ​​of the first and second distances can be arbitrarily set according to the communication method adopted.

[0023] The control means 23 controls the operation of the mobile terminal 20 to perform tasks such as detecting the location of the mobile terminal 20, transmitting distribution data, and collecting logs. The positioning means 24 includes, for example, a GPS (Global Positioning System) receiver and acquires the current locations of the mobile body 40 and the mobile terminal 20. The positioning means 24 outputs the generated location information to the control means 23. Note that the positioning means 24 may acquire location information using other technologies such as beacons or Wi-Fi positioning, not just GPS.

[0024] The fixed terminal 30 includes a storage means 31, a communication means 32, a control means 33, and a display means 34. The storage means 31 stores the operating programs and content data necessary for the fixed terminal 30, as well as log data such as environmental data and communication history acquired from sensors, etc. The storage means 31 also stores status information indicating the update status of the distributed data (version, update date, update time, etc.) or the communication status of the fixed terminal 30.

[0025] Communication means 32 is responsible for the communication function of the fixed terminal 30 and performs wireless communication with other fixed terminals 30 located within the communication range. Communication means 32 can relay packets received from other fixed terminals 30 and forward them to yet another fixed terminal 30, thereby realizing information propagation in a bucket brigade manner. In addition, communication means 32 can perform wireless communication with the mobile terminal 20, and when the mobile terminal 20 approaches within a second distance, it receives content data and transmits accumulated log data.

[0026] The control means 33 controls various parts of the fixed terminal 30 to perform data version control, data display control, etc. The display means 34 is a means for visually displaying information and is composed of, for example, electronic paper, liquid crystal panel, organic EL panel, etc. The display means 34 can display, for example, the latest timetable data, bus operation status, emergency information such as during disasters, etc. The display means 34 updates the displayed content according to instructions from the control means 33.

[0027] Figure 3 illustrates the hardware configuration of the management server 10. In this example, the management server 10 comprises a CPU 101, RAM 102, ROM 103, storage 104, and a communication interface 105 as physical components. These components are interconnected via a bus.

[0028] CPU 101 is an example of a processor that performs arithmetic processing. CPU 101 is implemented by one or more chips. RAM 102 is an example of volatile memory that provides a temporary workspace. ROM 103 is an example of non-volatile memory. Storage 104 is an example of auxiliary storage device that stores large amounts of data and is implemented by an HDD or SSD, etc. Communication interface 105 is hardware for communicating with external devices and includes an adapter for wireless communication.

[0029] The CPU 101 functions as a communication means 12, a management means 13, and a control means 14 by executing a program. The storage 104 functions as a storage means 11 that stores database files such as the fixed terminal management table 111 and the distribution data DB 112, and in this example, it also stores log data collected from the mobile terminal 20. The communication interface 105 communicates with the mobile terminal 20 and the fixed terminal 30.

[0030] Figure 4 illustrates the hardware configuration of the mobile terminal 20. The mobile terminal 20 is, for example, an information processing device such as a dedicated in-vehicle device, a tablet terminal, or a smartphone, and is physically configured as a computer including a processor 201, memory 202, GPS module 203, and communication module 204.

[0031] The processor 201 is a processing unit such as a CPU, which executes the operating system and various programs. The memory 202 is a storage medium such as ROM, RAM, or non-volatile memory, which stores programs and data. The GPS module 203 is a receiving device that receives signals from positioning satellites and generates its own position information. The communication module 204 is a wireless communication device compliant with the IEEE 802.11ah standard, etc., and uses the sub-gigahertz band, so it has high diffraction properties and is resistant to obstacles. Therefore, the communication module 204 is suitable for data transfer from a moving body 40 to a roadside fixed terminal 30.

[0032] Figure 5 illustrates the hardware configuration of the fixed terminal 30. The fixed terminal 30 comprises, as physical components, a microcontroller 301, storage 302, a wireless communication module 303, an electronic paper 304, a sensor 305, and a battery / solar panel 306. The fixed terminal 30 is preferably housed in a casing with environmental resistance suitable for outdoor installation. Each component operates using power supplied from the battery / solar panel 306.

[0033] The microcontroller 301 is a low-power microcontroller that operates intermittently, starting up periodically or when a communication request is received. The storage 302 is a non-volatile memory such as flash memory. The storage 302 holds content data, firmware, and routing information. The wireless communication module 303 is a communication device that supports a common communication method with the communication module 204 of the mobile terminal 20. The wireless communication module 303 performs ad-hoc or mesh communication with other fixed terminals 30 or the mobile terminal 20. The electronic paper 304 is a display device that can hold display content without power. The electronic paper 304 is an example of a display device and displays information such as timetables. Sensors 305 include a human presence sensor, a temperature sensor, and an illuminance sensor, which collect various measurement information.

[0034] Figure 6 is a diagram illustrating multiple clusters 300. The communication system 1 according to this embodiment includes multiple fixed terminals 30 distributed over a wide area. Each fixed terminal 30 has a predetermined communication range 310 centered on itself, and the multiple fixed terminals 30 constituting one cluster 300 are located in a positional relationship where the communication ranges 310 of neighboring fixed terminals 30 partially overlap. Fixed terminals 30 can communicate wirelessly with neighboring fixed terminals 30 by utilizing the overlap of their communication ranges 310.

[0035] Because the fixed terminals 30 are distributed over a wide area, there may be multiple independent clusters 300 where the chain of communication ranges 310 is interrupted and direct communication with each other is impossible. Of the multiple clusters 300, the fixed terminals 30 of cluster 300a, which includes the management server 10 at site 50, can receive information from the management server 10 through communication between the fixed terminals 30. On the other hand, in cluster 300b, which does not include the management server 10, information cannot be received from the management server 10 through communication between the fixed terminals 30 alone.

[0036] The communication system 1 according to this embodiment utilizes a mobile unit 40 and a mobile terminal 20 to complement the distribution of information to such clusters 300b. When the mobile unit 40 moves to the vicinity of cluster 300b, a fixed terminal 30 belonging to cluster 300b enters the communication range of the mobile terminal 20, and the mobile terminal 20 can establish wireless communication with the fixed terminal 30. The mobile terminal 20 transmits data acquired from the management server 10 to the fixed terminal 30, and the fixed terminal 30, upon receiving the data, forwards the data to other fixed terminals 30 within cluster 300b. This makes it possible to distribute information even to clusters 300b isolated from the management server 10.

[0037] Figure 7 illustrates a measure to address communication interruptions within a cluster. When the communication ranges 310 of multiple fixed terminals 30 overlap within a cluster 300, information can be transferred within the cluster 300 using a bucket brigade or mesh communication method. However, in some fixed terminals 30 constituting the cluster 300, communication failures may cause the communication range 310, shown by the dotted line in Figure 7, to shrink or disappear. In this case, the communication relay via the fixed terminal 30 is interrupted, and the cluster 300 is divided into multiple regions. When the cluster 300 is divided in this way, there is a possibility that the distributed information may not reach the fixed terminals 30 in the divided region.

[0038] In such a communication disruption state, the mobile unit 40 and the mobile terminal 20 function as physical means of transporting data. The mobile terminal 20 can receive distribution data from the management server 10 or other fixed terminals 30 that can communicate. When the mobile unit 40 moves to the vicinity of a fixed terminal 30 located in a fragmented area, the mobile terminal 20 transmits the distribution data to the target fixed terminal 30. As a result, even if a disruption occurs in the cluster 300, the mobile unit 40 and the mobile terminal 20 can supplement the distribution of information, making it possible to distribute information to the entire system.

[0039] Figure 8 illustrates a data distribution sequence by fixed terminals within a cluster. This sequence shows normal operation when the communication network between fixed terminals 30 is functioning correctly. If there is a fixed terminal 30 (master unit) located within the communication range of the management server 10 in the cluster, in step S801, the management server 10 distributes data packets of distribution data to the master unit. These data packets include, for example, timetable update data. When the master unit fixed terminal 30 receives these data packets, it stores them in its storage 302 and updates the display content of the display means 34 as necessary. In step S802, the fixed terminal 30 forwards the distribution data to other nearby, communicable fixed terminals 30. Here, the other fixed terminals 30 are slave units located outside the communication range of the management server 10.

[0040] In step S803, the fixed terminal 30 (slave) that receives the data further forwards the distribution data to another fixed terminal 30 located within its communication range. In other words, each fixed terminal 30 performs multi-hop communication based on a so-called bucket brigade method or mesh communication protocol. At this time, each fixed terminal 30 checks the version information or timestamp of the received distribution data and determines whether the information of the received distribution data is newer than the information held in its storage 302. The fixed terminal 30 can avoid unnecessary data overwriting by performing data update processing only when the information is newer. In addition, the fixed terminal 30 may forward only information newer than information previously forwarded, or prevent loop forwarding of data packets within the cluster by using TTL (Time To Live), sequence number management, etc.

[0041] In step S804, a fixed terminal 30 that has completed updating its data generates an acknowledgment (ACK) indicating this and sends it toward the management server 10 (the upstream side from which the distributed data was transferred). In step S805, the acknowledgment is forwarded by each fixed terminal 30 toward the management server 10. In step S806, the management server 10 receives the acknowledgment from each fixed terminal 30 via the master unit. Based on the received acknowledgment, the management server 10 updates the status information of each fixed terminal 30 recorded in the fixed terminal management table 111. Specifically, the management server 10 rewrites the version of the data held by the corresponding fixed terminal 30 to the latest value. The management server 10 obtains and updates the status information of fixed terminals 30 in clusters 300 to which it does not belong via the mobile terminal 20.

[0042] Figure 9 illustrates the data structure of the fixed terminal management table 600. In this embodiment, the fixed terminal management table 600 is stored in the storage means 11 of the management server 10. The management server 10 can centrally manage the status of multiple fixed terminals 30 distributed throughout the system using the fixed terminal management table 600. The fixed terminal management table 600 holds multiple records corresponding to each fixed terminal 30. Each record includes a field (information item) that stores attribute information or status information of the fixed terminal 30.

[0043] The attribute information of the fixed terminal 30 includes, for example, terminal ID 601, installation location information 602, and cluster ID 603. Changeable status information includes, for example, communication status flag 604 and retained data version 605. This information is updated based on periodic reports from the fixed terminal 30 or log data brought back by the mobile terminal 20. The management server 10 operates to keep this information up-to-date at all times.

[0044] Terminal ID 601 is identification information used to uniquely identify each fixed terminal 30. Terminal ID 601 may be, for example, a serial number assigned at the time of manufacture, a MAC address, or a logical ID code assigned during system operation. The management server 10 can use Terminal ID 601 as a search key to issue distribution instructions and check the status of a specific fixed terminal 30.

[0045] The installation location information 602 is coordinate information indicating the location where the fixed terminal 30 is physically installed, and includes, for example, latitude and longitude data. By using this installation location information 602, the management server 10 can compare the operating route of the mobile body 40 with the positional relationship of the fixed terminals 30 and determine which fixed terminals 30 the mobile body 40 will pass near.

[0046] Cluster ID 603 is information used to identify the cluster 300 to which each fixed terminal 30 belongs, and fixed terminals 30 belonging to the same cluster 300 share the same cluster ID 603. Communication status flag 604 is a flag that indicates the current communication capability of each fixed terminal 30, and can take values ​​such as "online," "offline," or "requires confirmation." "Online" indicates a state in which communication is accessible within the cluster 300 to which it belongs. "Offline" indicates a state in which access within the cluster 300 is impossible due to a failure of communication equipment, a power outage, or a disruption of the relay route. "Requires confirmation" indicates a state in which the feasibility of access is unknown due to response delays, etc. The control means 14 of the management server 10 can determine the target of physical data transport by the mobile terminal 20 by extracting fixed terminals 30 whose communication status flag 604 value is "offline."

[0047] The retained data version 605 indicates the version number of the content data (distribution data) currently held by the fixed terminal 30. The retained data version 605 may be, for example, a timestamp indicating the date and time the data was created, a sequence number indicating the number of updates, or a hash value generated from the data content. By comparing the version of the latest data in the distribution data DB 112 with the retained data version 605, the management server 10 can narrow down the targets for which updated data distribution is necessary, and duplicate distribution to fixed terminals 30 that already hold the latest data is avoided.

[0048] Figure 10 illustrates the control processing flow for data distribution by the mobile terminal 20. In step S901, the management means 13 of the management server 10 performs monitoring processing and periodically collects status information of each fixed terminal 30 for the cluster 300a to which the management server 10 itself belongs. The management means 13 also updates the fixed terminal management table 600 based on the collected status information.

[0049] In step S902, the management means 13 of the management server 10 collects status information of fixed terminals 30 for clusters 300b to which the management server 10 does not belong, via the mobile terminal 20. The mobile terminal 20 transmits the status information of each fixed terminal 30, which it collected when passing near clusters 300b as the mobile body 40 moves, to the management server 10 when it reaches the communication range of the management server 10. The management server 10 updates the fixed terminal management table 600 based on the received status information. This allows the management means 13 of the management server 10 to grasp the latest operating status of clusters 300b in remote locations. In other words, the management means 13 can manage the status of fixed terminals 30 distributed over a wide area by using a combination of direct monitoring and indirect monitoring via the mobile terminal 20.

[0050] In step S903, the control means 14 of the management server 10 periodically checks the data version and other information held in the fixed terminal management table 600 to identify areas where data to be distributed has not yet arrived as communication failure areas. Here, communication failure areas include, for example, areas where the sequential transfer of distribution data by multiple fixed terminals 30 is interrupted due to a failure in the communication function of a fixed terminal 30, resulting in the distribution data not being delivered, and areas in cluster 300b to which the management server 10 does not belong, where the distribution data has not been delivered for reasons such as the mobile terminal 20 storing the distribution data not having passed through cluster 300b. By identifying communication failure areas, the targets for which physical data transport is necessary are clarified.

[0051] In step S904, the control means 14 of the management server 10 selects a mobile body 40 to physically transport data to the identified communication failure area. In this selection process, the control means 14 refers to information such as the planned route of each mobile body 40 equipped with a mobile terminal 20, and searches for a mobile body 40 that is scheduled to pass near (within a second distance) a fixed terminal 30 located in the communication failure area. If there are multiple candidate mobile bodies 40, the management server 10 can select, for example, the mobile body 40 that can distribute the data the fastest. The selection criteria are not limited to the speed of arrival. The management server 10 may also select the optimal mobile body 40 by considering the remaining load capacity of the mobile body 40, the remaining fuel or battery level, or communication costs. Furthermore, the management server 10 may select not only regularly scheduled buses, but also mobile bodies 40 that operate irregularly, such as on-demand buses or taxis.

[0052] In step S905, the management server 10 sends a physical transport instruction and distribution data to the mobile terminal 20 of the selected mobile unit 40. The physical transport instruction includes a list of target fixed terminals 30, and the distribution data is sent, for example, as a data package. As a result, the mobile terminal 20 is controlled to physically transport the distribution data toward the communication loss area.

[0053] Figure 11 illustrates the data structure in the data package 700 of the distributed data. In this embodiment, the data package 700 is a logical unit of data entrusted from the management server 10 to the mobile terminal 20, or data transferred between fixed terminals 30. The management server 10 generates the data package 700 to deliver information to areas where the communication network is interrupted. The data package 700 functions as a container for reliably transmitting information between each device.

[0054] The data package 700 includes, for example, a package ID 701 that uniquely identifies the package. The package ID 701 is a system-wide unique identifier. Each fixed terminal 30 can determine duplicate data communication based on the package ID 701. The data package 700 also includes, for example, a distribution area / terminal list 702 that specifies the destinations for data distribution. The distribution area / terminal list 702 specifies a list of IDs of specific fixed terminals 30, a specific cluster ID, or information indicating a geographical range. By referring to this list, the mobile terminal 20 can determine which fixed terminal 30 to pass the data it is carrying to, or when to start transmitting after entering a certain area. In other words, the mobile terminal 20 can communicate only where necessary, enabling efficient data distribution.

[0055] The data package 700 includes the content data 703 that is actually distributed. The content data 703 is the actual information provided to the user and includes, for example, updated timetable data, service information, notices in PDF format, advertising images, or local news. The content data 703 can take any format, such as text, images, videos, or binary data. The fixed terminal 30 stores the received content data 703 in the storage means 31 and displays it on the display means 34. The content data 703 may be compressed to improve communication efficiency.

[0056] The data package 700 may include, for example, control commands 704 for display control and device control. The control commands 704 are a group of commands that include remote instructions to the fixed terminal 30, specifically instructing the fixed terminal 30 to restart, forcibly upload logs, update firmware, or change display brightness. The control means 33 of the fixed terminal 30 can change its operating mode or execute specified processes according to the control commands 704, and the management server 10 can perform maintenance and configuration changes on the fixed terminal 30, which is difficult to communicate with directly, via the mobile terminal 20.

[0057] The data package 700 may include, for example, a data expiration date 705. The expiration date 705 is time information for managing the freshness of the information, and indicates, for example, the end date and time or validity period of the data. The fixed terminal 30 periodically checks the expiration date 705 of the stored data and discards expired data or moves it to the archive area. This prevents the fixed terminal 30 from continuing to display old timetables or completed event information and prevents the depletion of storage resources.

[0058] Figure 12 illustrates a data transport sequence using the mobile terminal 20. This sequence shows the process of physically transporting and distributing data using the mobile device 40 to areas where communication infrastructure is disrupted or where direct communication with the management server 10 is not possible.

[0059] In step S1001, the mobile terminal 20 is located within the communication range of the management server 10. The communication range of the management server 10 is, for example, a Wi-Fi area set up at a base 50 such as a bus depot. In step S1001, the mobile terminal 20 establishes a communication connection with the management server 10, receives a transport instruction and a data package 700, and stores them in the storage means 21.

[0060] In step S1002, the mobile body 40, equipped with the mobile terminal 20, moves along a predetermined route or an arbitrary route in accordance with normal operating procedures. As the mobile body 40 moves, the data package 700 stored in the storage means 21 of the mobile terminal 20 is physically transported. In other words, the process in step S1002 is an example of a data transport phase in which digital data is transported through physical space while stored on a recording medium, rather than being transmitted as radio waves.

[0061] In step S1003, the control means 23 of the mobile terminal 20 controls the communication means 22 to periodically acquire terminal information of the fixed terminals 30 that can communicate, and compares the acquired terminal information with the distribution target area / terminal list 702 included in the data package 700. Based on this comparison result, the control means 23 determines whether or not the mobile terminal has entered the distribution target area where the fixed terminals 30 to be distributed are installed.

[0062] Upon entering the distribution area, in step S1004, the mobile terminal 20 controls the communication means 22 to send a connection request to the target fixed terminal 30 and establish a local communication link. This connection request is, for example, a probe request or association request in a wireless LAN. This local communication link is a direct wireless connection between terminals that does not go through a wide area network such as the Internet.

[0063] Once a communication link is established, in step S1005, the mobile terminal 20 transmits the data package 700 it holds to the fixed terminal 30, and the fixed terminal 30 receives this data package 700. At this time, the mobile terminal 20 can check the version of the data held by the fixed terminal 30 and transmit only the data that needs to be updated. Furthermore, the mobile terminal 20 does not need to communicate individually with all the fixed terminals 30 belonging to the isolated cluster 300b. When the mobile terminal 20 passes the distribution data to the fixed terminal 30 that becomes the entry point to cluster 300b, i.e., the first fixed terminal 30 to become communicable, the fixed terminal 30 that receives the data and the other fixed terminals 30 perform the transfer process within the isolated cluster 300b using a bucket brigade or mesh communication method. As a result, information received by, for example, one fixed terminal 30 from the mobile terminal 20 is disseminated to each fixed terminal 30 within cluster 300b. Therefore, information updates can be performed on an area-by-area or cluster-by-cluster basis without the mobile unit 40 having to pass near all the fixed terminals 30.

[0064] Figure 13 illustrates a detailed sequence of data synchronization processing between the mobile terminal 20 and the fixed terminal 30. This sequence is executed when the fixed terminal 30 enters the communication range (within the second distance) of the mobile terminal 20 due to the movement of the mobile body 40.

[0065] In step S1101, the mobile terminal 20 sends a logical connection request to the fixed terminal 30, and the fixed terminal 30 receives the connection request. If the fixed terminal 30 permits the connection, it sends an acknowledgment (ACK) or a connection permission message back to the mobile terminal 20. The mobile terminal 20 establishes a logical communication path upon receiving the response from the fixed terminal 30. At this time, the mobile terminal 20 and the fixed terminal 30 may perform mutual authentication processing. This prevents unauthorized data rewriting or eavesdropping by third-party devices.

[0066] In step S1102, the mobile terminal 20 queries the fixed terminal 30 for version information of the currently held data. Specifically, for example, the mobile terminal 20 sends a version confirmation request command to the fixed terminal 30. In step S1103, in response to the version information query, the fixed terminal 30 sends back a response message to the mobile terminal 20 that includes the held data version 605 of the content data currently held and available for display or distribution.

[0067] In step S1103, the mobile terminal 20, having acquired the retained data version 605, determines whether a data update is necessary for the fixed terminal 30. Specifically, the control means 23 of the mobile terminal 20 compares the acquired retained data version 605 with the version information of the content contained in the data package 700 stored in its own storage means 21. The control means 23 then determines that an update is necessary if the version of the data package 700 is newer than the retained data version 605. On the other hand, if the retained data version 605 of the fixed terminal 30 is already the latest version, or newer than the version of the data package 700, the control means 23 determines that an update is unnecessary. This determination avoids unnecessary data transmission, allowing for effective use of limited communication time and bandwidth.

[0068] If it is determined that an update is necessary, in step S1104, the mobile terminal 20 sends the update data to the fixed terminal 30. That is, the mobile terminal 20 extracts the content data 703 to be delivered to the fixed terminal 30 from the data package 700 and sends it to the fixed terminal 30 as update data. The fixed terminal 30 receives the update data and writes it to its storage means 31. The fixed terminal 30 may also send a completion notification to the mobile terminal 20 indicating that the data reception has been completed successfully.

[0069] In step S1105, the mobile terminal 20 sends a request to the fixed terminal 30 to upload log data. In step S1106, upon receiving the request, the fixed terminal 30 reads various log data stored in its storage means 31 and sends it to the mobile terminal 20. Here, the log data includes, for example, an operation log showing the operating status of the fixed terminal 30, a communication log showing communication errors and connection history, or environmental data (temperature, humidity, pedestrian flow data, etc.) acquired by the sensor 305. The processing in steps S1105 and S1106 is a data transfer process in the reverse direction (uplink direction) that is performed in conjunction with, or before or after, the transmission of distribution data (downlink direction).

[0070] The mobile terminal 20 stores the uploaded log data in its own storage means 21, and when the mobile body 40 returns to the communication range of the management server 10, it uploads the log data to the management server 10. This allows the management server 10 to obtain information from areas where it does not have direct communication means. In particular, even in communication-deprivation areas such as cluster 300b, to which the management server 10 does not belong, the mobile terminal 20 physically transports the data, enabling the management server 10 to understand the situation in that area and detect problems.

[0071] Variation This disclosure is not limited to the embodiments described above. Various modifications are possible. Several modifications are described below. At least some of the modifications described below may be used in combination with at least some of the other modifications or at least some of the embodiments described above.

[0072] (1) Data In the above embodiment, timetables, service information, local information, and advertising data were used as examples of the information to be distributed, but the types of data are not limited to these. The distributed data may also include announcements from the government, evacuation information in case of disaster, or coupon information from nearby stores. Furthermore, the distributed data may also include firmware update data for the fixed terminal 30, display screen layout definition files, etc. In addition, the distributed data may include video data and audio data, in which case the fixed terminal 30 is equipped with a function to play the received video data and audio data.

[0073] The data collected by the mobile terminal 20 from the fixed terminal 30 is not limited to log data. The mobile terminal 20 may collect environmental data acquired from the fixed terminal 30 by environmental sensors. The fixed terminal 30 may be equipped with a camera and a microphone, and the mobile terminal 20 may collect image data captured by the camera and audio data recorded by the microphone. This makes it possible for the management server 10 to collect local microclimate data and crime prevention information, and for example, to control agricultural sluice gates based on image data obtained from water level monitoring cameras. In addition, the fixed terminal management table 600 may include information other than the items described above. For example, the fixed terminal management table 600 may record the battery level of the fixed terminal 30, the operating status of the connected sensor 305, or a timestamp indicating the last communication time. Conversely, the mobile terminal 20 and the management server 10 may only distribute information to the fixed terminal 30 and not collect information from the fixed terminal 30.

[0074] (2) Content and order of processing In the above embodiment, an example was described in which the mobile body 40 passively carries data while traveling along a normal route, but the control of the mobile body 40 is not limited to this. The control means 14 may instruct the mobile body 40 to change its route if the data is of high urgency. For example, the control means 14 can generate a route that passes through a communication loss area and transmit this route to the navigation device of the mobile body 40 to instruct a route change. Also, if the mobile body 40 is an autonomous vehicle, the control means 14 may directly send a waypoint change command to the driving control system of the mobile body 40. If the mobile body 40 is a manned vehicle, the control means 14 may offer incentives (rewards or points) to the driver and encourage them to stop at the target area.

[0075] The timing of data distribution is not limited to after detecting a communication disruption. The management server 10 may predict the occurrence of a communication disruption based on past communication history, weather forecast data, etc. The management server 10 may also pre-control the mobile terminals 20 so that data is distributed to areas where a communication disruption is predicted. For example, if an approaching typhoon is predicted, the management server 10 may pre-transmit information on evacuation centers and disaster prevention maps to the mobile terminals 20 in preparation for distribution to each fixed terminal 30. This ensures that residents can obtain necessary information even after the communication infrastructure has actually gone down.

[0076] The bucket brigade method between fixed terminals 30 is not limited to simple flooding. Fixed terminal 30 may select the destination fixed terminal 30 depending on the destination and attributes of the data. Fixed terminal 30 may avoid transferring to other fixed terminals 30 with low battery levels. Fixed terminal 30 may prioritize selecting links with good communication quality. Fixed terminal 30 may manage the time to live (TTL) of the data it holds to prevent old data from accumulating in the network.

[0077] (3) Expansion or limitation of functions In the above embodiment, it was explained that the fixed terminal 30 autonomously forms a communication group (cluster), but the logic for this group formation can be dynamically changed. The fixed terminal 30 may change the group to which it belongs depending on the surrounding radio wave environment and the amount of communication traffic. The fixed terminal 30 may belong to multiple communication groups simultaneously. The mobile terminal 20 may move while retaining the data acquired in the first group, and when it enters the second group, it may transmit the data to the fixed terminal 30 in the second group. This makes it possible to share information between groups that are physically or communicationally separated.

[0078] The display means 34 of the fixed terminal 30 is not limited to electronic paper. The display means 34 may be a liquid crystal display, an organic EL display, or an LED matrix panel. The display means 34 may have a touch panel function and accept touch operations from the user. The fixed terminal 30 can switch the displayed content according to the user's operation. The fixed terminal 30 may store survey responses and messages entered by the user. The mobile terminal 20 can collect user input data and send it to the management server 10, thereby enabling two-way communication.

[0079] In the above embodiment, an example was described in which the mobile terminal 20 is installed on a mobile vehicle 40 such as a bus, but the mobile terminal 20 may also be a detachable portable device. Drivers, for example, can bring the mobile terminal 20 onto the mobile vehicle 40 at the start of their work and take it back with them at the end of their work. With a mobile terminal 20 of this form, it is possible to introduce the system of the present invention without modifying the mobile vehicle 40. The mobile terminal 20 may also be implemented as an application on a smartphone. In this case, the GPS function and Bluetooth function of the smartphone are used.

[0080] (4) System Configuration In the above embodiment, a route bus was used as an example of the mobile body 40, but the type of mobile body 40 is not limited to this. The mobile body 40 may be a taxi, a postal delivery vehicle, a waste collection vehicle, or a delivery truck. Preferably, the mobile body 40 is a vehicle that patrols a specific route. The mobile body 40 may be an unmanned mobile body such as a drone or an autonomous robot. The mobile body 40 may be a pedestrian or cyclist carrying a smartphone. In this case, a user terminal with a dedicated application installed functions as the mobile terminal 20, and the user terminal can transport data using the pass-by communication function. This makes it possible to build a more granular data distribution network.

[0081] The fixed terminal 30 is not limited to those installed at bus stops. The fixed terminal 30 may be installed on infrastructure equipment such as streetlights, traffic lights, vending machines, post boxes, digital signage, or utility poles. In particular, infrastructure equipment that is frequently passed by regularly patrolling mobile vehicles, such as vending machines and post boxes, is preferred. The fixed terminal 30 may also be installed in stores, sports facilities, leisure facilities, etc., and can be used to distribute information viewed in stores or facilities, or to distribute issued coupons. Stores along regular patrol routes of mobile vehicles such as buses and postal delivery vehicles are particularly preferred. The fixed terminal 30 is preferably equipped with an independent power source such as a solar panel, but may also be powered by a commercial power source. The fixed terminal 30 may function as a bulletin board in disaster evacuation shelters or as a tourist information board. The fixed terminal 30 can display or hold information according to the characteristics of the installation location.

[0082] The communication method of the fixed terminal 30 is not limited to Wi-Fi HaLow. Other LPWA standards such as LoRa(registered trademark)WAN, Sigfox, Wi-SUN, or Bluetooth(registered trademark) Low Energy (BLE) may be adopted for the fixed terminal 30. The fixed terminal 30 may utilize the side-link function (direct terminal-to-terminal communication) of 5G communication. The fixed terminal 30 may use visible light communication or sound wave communication to send and receive data. The fixed terminal 30 may switch between multiple communication methods as appropriate depending on the installation environment, required communication speed, and power consumption. The fixed terminal 30 may use different communication methods for communication with other fixed terminals 30 and for communication with the management server 10 and mobile terminals 20. For communication with the management server 10 and mobile terminals 20, the fixed terminal 30 may use, for example, Wi-Fi (Wireless Fidelity) communication. The mobile terminal 20 may communicate with the management server 10 via, for example, a mobile communication network, or it may use Wi-Fi (Wireless Fidelity) communication.

[0083] The functions of the management server 10 do not need to be implemented by a single server computer, but may be implemented by multiple server computers. The functions of the management server 10 may be run on a virtual machine in a cloud computing environment. Some or all of the functions of the management server 10 may be delegated to a specific fixed terminal 30 (for example, a master unit that acts as a regional hub). The functions of the management server 10 may be distributed across gateway devices in each area, based on the concept of edge computing. This reduces communication latency and improves autonomous operation in the event of a high-level network outage. [Explanation of Symbols]

[0084] 1...Communication system, 10...Management server, 11...Storage means, 12...Communication means, 13...Management means, 14...Control means, 20...Mobile terminal, 21...Storage means, 22...Communication means, 23...Control means, 24...Positioning means, 30...Fixed terminal, 30a...Fixed terminal (master unit), 30b...Fixed terminal (slave unit), 31...Storage means, 32...Communication means, 33...Control means, 34...Display means, 40...Mobile unit, 50...Location, 111...Fixed terminal management table, 112...Distribution data DB, 300, 300a, 300b...Cluster, 310...Communication range, 600...Fixed terminal management table, 700...Data package

Claims

1. Multiple fixed terminals capable of communicating with other fixed terminals located within a first distance from themselves, A mobile terminal capable of wireless communication with the fixed terminal within a second distance, A distribution means for distributing information to at least one of the aforementioned multiple fixed terminals, Control means for controlling the communication operation of the mobile terminal so that, if there is a fixed terminal among the plurality of fixed terminals that has not received the information from the other fixed terminals, the information is transmitted to that fixed terminal. A communication system equipped with [the following features].

2. In the communication system described in claim 1, The aforementioned fixed terminal maintains status information indicating the update status of the information or its own communication status. Communication system.

3. In the communication system described in claim 2, The mobile terminal obtains the status information from the fixed terminal and determines, based on the status information, whether the fixed terminal is an unupdated terminal or a terminal unable to communicate. Communication system.

4. In the communication system described in claim 1, The aforementioned fixed terminal autonomously forms or updates a communication group depending on the status of other fixed terminals with which it can communicate. Communication system.

5. In the communication system described in claim 4, When the mobile terminal moves between multiple communication groups, it distributes or synchronizes information held by one communication group to other communication groups. Communication system.

6. In the communication system described in claim 1, Each of the plurality of fixed terminals sequentially transfers the received information to other fixed terminals within the first distance, thereby propagating the information over a range wider than the first distance. Communication system.

7. In the communication system described in claim 1, The aforementioned fixed terminal holds or displays at least one of the following as information: operation information, congestion information, local information, and commercial information. Communication system.

8. In the communication system described in claim 1, The aforementioned fixed terminal is installed at the bus stop. The aforementioned mobile terminal is installed in a bus vehicle. Communication system.

9. A management means for managing the distribution status of information to multiple fixed terminals that can communicate with other fixed terminals located within a first distance from itself, Distribution means for distributing the information to at least one of the plurality of fixed terminals, When there is a fixed terminal among the plurality of fixed terminals that has not received the information from the other fixed terminals, control means control the communication operation of a mobile terminal that can wirelessly communicate with the fixed terminal within a second distance so that the information is transmitted to that fixed terminal. An information processing device equipped with the following features.

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