JP7067145B2 - Wireless communication system and communication path switching method - Google Patents

Description

The present invention relates to a wireless communication system and a method of switching a communication path .

In a wireless communication system including a plurality of wireless communication terminals, a technique is known in which content data is simultaneously transmitted (for example, broadcast transmission) from a source wireless communication terminal to another wireless communication terminal by multi-hop communication.

Further, in a wireless communication system that performs multi-hop communication, a technique is known in which a node station groups other node stations into a plurality of groups based on the strength of received radio waves and generates a routing table for each group (). For example, see Patent Document 1).

In a wireless communication system in which content data is simultaneously transmitted from a source wireless communication terminal to another wireless communication terminal by multi-hop communication, it is not always guaranteed that the content data will be transmitted to all wireless communication terminals. ..

This means that, for example, when a wireless communication terminal whose wireless communication is disconnected when changing the communication path of multi-hop communication can select a new connection destination, can the content data be transmitted to more wireless communication terminals? This is because it does not consider whether or not it is.

As described above, in the conventional technique, it is difficult to transmit the content data to more wireless communication terminals in the wireless communication system in which the content data is simultaneously transmitted from the transmission source wireless communication terminal by multi-hop communication. Was there.

The embodiment of the present invention has been made in view of the above problems, and is in a wireless communication system in which content data is simultaneously transmitted from a source wireless communication terminal to another wireless communication terminal by multi-hop communication. , Allows content data to be transmitted to more wireless communication terminals.

In order to solve the above problems, the wireless communication system according to the embodiment of the present invention includes a plurality of hopping terminals and a communication management device, and simultaneously transmits data from the source terminal to another terminal by multi-hop communication. The hopping terminal functions as an access point for millimeter-wave wireless communication, and serves as a first communication unit forming a network cell for the millimeter-wave wireless communication and a station for the millimeter-wave wireless communication. A second communication unit that functions and connects to a network cell formed by another hopping terminal, a third communication unit that performs wireless LAN communication with the communication management device, the first communication unit, and the second communication unit. Of the communication units of the above, the data transfer unit that transmits the data received by one communication unit to the other terminal by the other communication unit, and the second communication while transmitting the data to the other terminal. When the unit detects deterioration or disconnection of the communication quality of the millimeter-wave wireless communication, the communication management of the disconnection notification including the information of another hopping terminal that can be connected by the second communication unit is performed by the wireless LAN communication. It has an information transmission unit to be transmitted to the device and a connection control unit for connecting the second communication unit to the hopping terminal of the connection destination notified from the communication management device by the wireless LAN communication, and the communication management. The apparatus comprises the millimeter wave from the wireless LAN communication unit that performs wireless LAN communication with the hopping terminal and the first hopping terminal that detects deterioration or disconnection of the communication quality of the millimeter wave wireless communication among the hopping terminals. Based on the acquisition unit that acquires the information of the second hopping terminal that can be connected by wireless communication by the wireless LAN communication and the information of the second hopping terminal acquired by the acquisition unit, the second hopping terminal is used. , A classification unit for classifying into a first terminal group in which a communication path is connected to the source terminal and a second terminal group in which a communication path is not connected to the source terminal, and the classification unit. Of the first terminal group and the second terminal group classified by the above, the second hopping terminal included in a terminal group different from the terminal group to which the first hopping terminal belongs is connected to the connection destination. The hopping terminal includes a notification unit for notifying the first hopping terminal by the wireless LAN communication.

According to one embodiment of the present invention, in a wireless communication system in which content data is simultaneously transmitted from a source wireless communication terminal to another wireless communication terminal by multi-hop communication, the content data can be transferred to more wireless communication terminals. You will be able to send.

It is a figure (1) for demonstrating the millimeter-wave wireless communication system which concerns on one Embodiment. It is a figure (2) for demonstrating the millimeter-wave wireless communication system which concerns on one Embodiment. It is a figure for demonstrating the example of beamforming which concerns on one Embodiment. It is a figure which shows the structural example of the communication system which concerns on one Embodiment. It is a figure which shows the example of the hardware composition of the hopping node and the edge node which concerns on one Embodiment. It is a figure which shows the example of the hardware composition of the communication management apparatus which concerns on one Embodiment. It is a figure which shows the example of the functional structure of the hopping node which concerns on one Embodiment. It is a figure which shows the example of the functional structure of the edge node which concerns on one Embodiment. It is a figure which shows the example of the functional structure of the communication management apparatus which concerns on one Embodiment. It is a sequence diagram which shows the example of the registration process of the hopping node which concerns on 1st Embodiment. It is a figure for demonstrating the cutting determination which concerns on 1st Embodiment. It is a flowchart which shows the example of the processing of the hopping node which concerns on 1st Embodiment. It is a figure which shows the example of the network configuration at the time of disconnection which concerns on 1st Embodiment. It is a flowchart which shows the example of the notification processing of the connection destination which concerns on 1st Embodiment. It is a figure (1) which shows the image of the information managed by the communication system which concerns on 1st Embodiment. It is a figure (2) which shows the image of the information managed by the communication system which concerns on 1st Embodiment. It is a figure which shows the example of the network configuration after the route switching which concerns on 1st Embodiment. It is a sequence diagram which shows the example of the processing of the communication system which concerns on 1st Embodiment. It is a flowchart which shows the example of the notification processing of the connection destination which concerns on 2nd Embodiment. It is a figure which shows the example of the updated communication route table which concerns on 2nd Embodiment. It is a figure which shows the example of the network configuration after the route switching which concerns on 2nd Embodiment. It is a sequence diagram which shows the example of the processing of the communication system which concerns on 2nd Embodiment. It is a sequence diagram which shows the example of the processing of the communication system which concerns on 3rd Embodiment. It is a sequence diagram which shows the example of the activation processing of the hopping node which concerns on one Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

<Overview of millimeter-wave wireless communication system>
Before explaining the embodiment of the present invention, the outline of the millimeter wave wireless communication system related to each embodiment of the present invention will be described.

The millimeter-wave wireless communication system is a wireless communication system that transmits data at high speed using a millimeter-wave (60 GHz) band in which radio waves have high straightness and a communication range is relatively narrow. Here, the following description will be given assuming that the millimeter-wave wireless communication system is a wireless communication system compliant with IEEE (Institute of Electrical and Electronics Engineers) 802.11ad. In addition, IEEE802.11ad is an example of the millimeter wave wireless communication system according to this embodiment.

(Network configuration)
The millimeter-wave wireless communication system compliant with IEEE802.11ad communicates using the millimeter-wave (60 GHz) band, which has high radio wave straightness and a relatively narrow communication range, and uses a wide band of 2.16 GHz per channel. This realizes high-speed data communication.

Further, in the millimeter wave band, the propagation loss of radio waves becomes large, so in the millimeter wave wireless communication system, a beamforming technique for narrowing down the beam direction of radio waves to transmit and receive radio waves is used in order to increase the antenna gain. Therefore, it is basically difficult for the communication unit of the millimeter-wave wireless communication system to communicate with a plurality of communication devices at the same time.

Therefore, in the millimeter-wave wireless communication system, a TDMA (Time Division Multiple Access) communication protocol is used as the wireless multiplexing method instead of the CSMA / CA method used in the conventional wireless LAN (Local Area Network) system. Be done.

In a millimeter-wave wireless communication system, a coordinator device called an AP (Access Point) forms a network cell called a BSS (Basic Service Set) and manages time slots in the TDMA protocol.

1 and 2 are diagrams for explaining a millimeter-wave wireless communication system according to an embodiment. FIG. 1A shows an example of a one-to-one network configuration in which AP110 forming a BSS100, which is a network cell of a millimeter-wave wireless communication system, and STA (Station) 120 communicate with each other by millimeter-wave wireless communication 130. Shows. In the example of FIG. 1 (a), the AP 110 manages the time slot in the TDMA protocol and transmits, for example, a beacon frame at a predetermined time interval.

FIG. 1B shows an example of a star-type network configuration in which the AP 110 forming the BSS 100 and a plurality of STAs 120-1 to 120-3 communicate with each other by the millimeter wave wireless communication 130. Also in the example of FIG. 1 (b), the AP 110 manages the time slot in the TDMA protocol and transmits, for example, a beacon frame at a predetermined time interval.

In IEEE802.11ad, in addition to the network configuration shown in FIGS. 1 (a) and 1 (b), as shown in FIG. 2 (a), a PBSS (Personal Basic Service Set) 200 formed by a coordinator device called a PCP is used. A network configuration called is defined. In PBSS200, STAs 120-1 to 120-3 can communicate with other STAs via PCP201, or can communicate with other STAs without going through PCP201.

(Time slot configuration)
FIG. 2B is a diagram showing an example of a time slot according to an embodiment. FIG. 2B shows the time slot allocation in the TDMA protocol managed by AP110. As shown in FIG. 2B, the time slot of the TDMA protocol managed by the AP 110 includes a BHI (Beacon Header Interval) and a DTI (Data Transfer Interval).

BHI includes BTI (Beacon Transmission Interval), A-BFT (Association Beamforming Training), and ATI (Announcement Transmission Interval).

BTI is the period during which AP110 transmits a beacon frame. A-BFT is a beamforming training period. ATI is a period for transmitting and receiving management information, control information, and the like between AP110 and STA120-1 to 120-3.

DTI includes CBAP (Contention Based Access Period) and SP (Service Period).

CBAP is a conflict period allocated for AP110 and a plurality of STA120s to compete and communicate with each other. The SP is a dedicated period allocated for communication between the AP 110 and one STA 120.

In BTI, the AP 110 transmits as many beacon frames as the number of antenna sectors, which are a plurality of beam patterns formed by the AP 110. On the other hand, the STAs 120-1 to 120-3 are set to the omnidirectional antenna or the quasi-omnidirectional antenna to receive all the beacon frames transmitted from the AP, and the information indicating the antenna sector having the best reception quality is transmitted to the AP110. provide feedback. As a result, the AP 110 can grasp whether to communicate with each STA120-1 to 120-3 by using the antenna sector.

(Beamforming)
Here, only an outline of SLS (Sector Level Sweep) will be described as an example of beamforming technology.

There are two types of SLS, TXSS (Tx Sector Sweep) and RXSS (Rx Sector Sweep). TXSS is a beamforming training for determining an antenna sector to be used at the time of transmission, and RXSS is a beamforming training for determining an antenna sector to be used at the time of reception.

FIG. 3 is a diagram for explaining an example of beamforming according to an embodiment. In the example of FIG. 3, for the sake of simplicity, only four antenna sectors of sectors 1 to 4 are shown among the antenna sectors which are a plurality of beam patterns formed by the AP 110.

In the TXSS, the AP 110 forms the BSS 300 by switching each sector (sectors 1 to 4) of the plurality of beam patterns 303 from the antenna 301 and sequentially transmitting predetermined packets. On the other hand, the STA 120 sets the antenna 302 to an omnidirectional antenna or a quasi-omnidirectional antenna, receives the packet transmitted from the AP 110, and feeds back the information indicating the antenna sector having the best reception quality to the AP 110.

In RXSS, a beamforming training sequence in the direction opposite to that of TXSS is executed, and when TXSS and RXSS are completed, radio waves can be transmitted and received by millimeter wave wireless communication between AP110 and STA120.

<System configuration>
Subsequently, the configuration of the communication system according to the present embodiment will be described.

FIG. 4 is a diagram showing a configuration example of a communication system according to an embodiment. The communication system (wireless communication system) 400 has, for example, a plurality of hopping nodes 401-1 to 401-5, one or more edge nodes 402-1 to 402-7, and a communication management device 403. In the following description, when indicating an arbitrary hopping node among a plurality of hopping nodes 401-1 to 401-5, "hopping node 401" is used. Further, when indicating an arbitrary edge node among one or more edge nodes 402-1 to 402-7, "edge node 402" is used.

The hopping node (hopping terminal) 401 is a first communication unit that functions as an AP for millimeter-wave wireless communication, a second communication unit that functions as an STA for millimeter-wave wireless communication, and a third communication unit that performs wireless LAN communication. It is a communication device provided with. The millimeter-wave wireless communication is an example of wireless communication in which multi-hop communication is performed using a radio wave having directivity. Further, the wireless LAN communication is an example of the second wireless communication having a wider communication range than the first wireless communication. Further, the hopping node 401 is an example of a wireless communication terminal.

The plurality of hopping nodes 401-1 to 401-5 use the first communication unit to form different network cells (BSS) from each other in millimeter-wave wireless communication. For example, in FIG. 4, the hopping node 401-1 forms the network cell 406-1, and the hopping node 401-2 forms the network cell 406.2. Further, it is assumed that the hopping node 401-3 forms the network cell 406-3, and the other hopping nodes also form the network cell in the same manner.

Further, the hopping node 401 can be connected to a network cell formed by another hopping node by using the second communication unit. In the example of FIG. 4, the hopping node 401-2 is connected to the network cell 406-1 formed by the first communication unit (AP) of the hopping node 401-1 by using the second communication unit (STA). It can be connected by wave wireless communication. Further, the hopping node 401-1 is connected by the second communication unit (STA) to the network cell 406-3 formed by the first communication unit (AP) of the hopping node 401-3 by millimeter wave wireless communication. be able to. Similarly, the hopping node 401-3 is connected by the second communication unit (STA) to the network cell formed by the first communication unit (AP) of the hopping node 401-4 by millimeter wave wireless communication. Can be done.

Further, the plurality of hopping nodes 401-1 to 401-5 are included in the same wireless LAN network 407 as the communication management device 403, and the third communication unit can be used to perform wireless LAN communication with the communication management device 403. can. The access point for wireless LAN communication may be the communication management device 403 or may use another access point.

The edge node (edge terminal) 402 is a communication device including a fourth communication unit that functions as an STA for millimeter-wave wireless communication, and is connected to one network cell among a plurality of network cells formed by the edge node 402. ..
In the example of FIG. 4, the edge nodes 402-1 to 402-3 use the fourth communication unit (STA), and the network cell 406- formed by the first communication unit (AP) of the hopping node 401-1. It is connected to 1.

Further, although not essential, the edge node 402 may further have a communication unit for performing wireless LAN communication. For example, the broken line 404 in FIG. 4 shows the connection relationship between the devices by wireless LAN communication, and it is shown that the edge node 402-6 can communicate with the communication management device 403 by wireless LAN communication. .. Similarly, it is shown that the plurality of hopping nodes 401-1 to 401-5 can communicate with the communication management device 403 by wireless LAN communication.

In the above configuration, each hopping node 401 collects information on peripheral communication devices by millimeter-wave wireless communication using a second communication unit (STA), and the collected information is used as a communication management device by wireless LAN communication. Send to 403.

The communication management device (communication management terminal) 403 uses the information received by wireless LAN communication from each hopping node 401, for example, the connection relationship between the devices by millimeter wave wireless communication as shown by the solid line 405 in FIG. To manage. Further, when multi-hop communication by millimeter wave wireless communication is performed, the communication management device 403 determines a data communication path based on the specified connection relationship, and gives an instruction regarding the communication path to the hopping node 401 in the communication path. Send by wireless LAN communication.

The hopping node 401 receives data received by one of the first communication unit and the second communication unit based on the instruction regarding the communication path notified from the communication management device 403 by wireless LAN communication. Transfer to another communication device in the other communication unit.

As described above, in the present embodiment, the hopping node 401 has two millimeter-wave communication units, and the data received by one communication unit can be transferred to another communication device by the other communication unit. Video data, audio data, etc. can be easily stream-transferred.

<Hardware configuration>
(Hardware configuration of hopping node)
FIG. 5A shows an example of the hardware configuration of the hopping node 401. The hopping node 401 may be, for example, a CPU (Central Processing Unit) 511, a RAM (Read Only Memory) 512, a ROM (Read Only Memory) 513, a storage unit 514, a wireless LAN communication device 515, a millimeter wave wireless communication device 516-1, and the like. It has 516-2, ramp 517, bus 518 and the like.

The CPU 511 is an arithmetic unit that realizes each function of the hopping node 401 by reading a program or data stored in a ROM 513, a storage unit 514, or the like on the RAM 512 and executing processing. The RAM 512 is a volatile memory used as a work area or the like of the CPU 511. The ROM 513 is a non-volatile memory that can hold programs and data even when the power is turned off.

The storage unit 514 is, for example, a storage device such as an HDD (Hard Disk Drive), SSD (Solid State Drive), or flash ROM, and stores an OS (Operating System), an application program, various data, and the like.

The wireless LAN communication device 515 is a wireless communication device for performing wireless LAN communication conforming to a standard such as IEEE802.11a / b / g / n / ac, and is, for example, an antenna, a wireless unit, and a MAC (Media Access). Control) unit, communication control unit, etc. are included.

The millimeter-wave wireless communication device 516-1 and 516-2 are, for example, wireless communication devices for performing millimeter-wave wireless communication compliant with standards such as IEEE802.11ad, and are, for example, an antenna, a wireless unit, a MAC unit, and communication. Includes control unit, etc.

The lamp 517 is a light emitting element for displaying, for example, the operating state of the hopping node 401 by changing the color, lighting / blinking, or the like. The bus 518 is connected to each of the above components and transmits an address signal, a data signal, various control signals, and the like.

(Hardware configuration of edge node)
FIG. 5B shows an example of the hardware configuration of the edge node 402. The edge node 402 includes, for example, a CPU 521, a RAM 522, a ROM 523, a storage unit 524, a wireless LAN communication device 525, a millimeter-wave wireless communication device 526, a display device 527, an input device 528, a bus 529, and the like. Of these, the configurations of the CPU 521, RAM 522, ROM 523, storage unit 524, wireless LAN communication device 525, millimeter wave wireless communication device 526, bus 529, etc. are the same as the configurations of the respective parts described in the hopping node 401, so the description is given here. Omit.

The display device 527 is a display device such as a liquid crystal display that displays a display screen. The input device 528 is an input device such as a touch panel or a keyboard that accepts a user's input operation.

The configuration of the edge node 402 shown in FIG. 5 is an example, and the edge node 402 does not have to have the wireless LAN communication device 525.

(Hardware configuration of communication management device)
FIG. 6 is a diagram showing an example of the hardware configuration of the communication management device according to the embodiment. The communication management device 403 includes, for example, a CPU 601, a RAM 602, a flash ROM 603, a wireless LAN communication device 604, a bus 605, and the like.

The CPU 601 is an arithmetic unit that realizes each function of the communication management device 403 by executing a program stored in the flash ROM 603 or the like. The RAM 602 is a volatile memory used as a work area or the like of the CPU 511. The flash ROM 603 is a rewritable non-volatile memory that can hold programs and data even when the power is turned off.

The wireless LAN communication device 604 is a wireless communication device for performing wireless LAN communication. The bus 605 is connected to each of the above components and transmits an address signal, a data signal, various control signals, and the like.

<Functional configuration>
Subsequently, the functional configuration of each device will be described.

(Functional configuration of hopping node)
FIG. 7 is a diagram showing an example of the functional configuration of the hopping node according to the embodiment. The hopping node (hopping terminal) 401 includes a wireless LAN communication unit 701, a millimeter wave wireless communication unit (AP) 702, a millimeter wave wireless communication unit (STA) 703, a storage unit 704, and the like. Further, the hopping node 401 includes a communication link state measurement unit 711, an information collection unit 712, a data transfer unit 713, a disconnection determination unit 714, an edge node management unit 715, an information transfer unit 716, a connection control unit 717, and the like. Further, the hopping node 401 has an information transmission unit 721, an information reception unit 722, a registration request unit 723, and the like.

The wireless LAN communication unit (third communication unit) 701 is realized by, for example, a program executed by the wireless LAN communication device 515 of FIG. 5A and the CPU 511 of FIG. 5A. The wireless LAN communication unit 701 connects the hopping node 401 to the wireless LAN network 407 and performs wireless LAN communication with the communication management device 403.

The millimeter-wave wireless communication unit (AP) 702 is realized by, for example, a program executed by the millimeter-wave wireless communication device 516-1 of FIG. 5A and the CPU 511 of FIG. 5A. The millimeter-wave wireless communication unit (AP) 702 functions as an AP (access point) for millimeter-wave wireless communication and forms a network cell for millimeter-wave wireless communication. Further, the millimeter-wave wireless communication unit (AP) 702 transmits / receives data by millimeter-wave wireless communication with the STA of millimeter-wave wireless communication connected to the formed network cell. The millimeter wave wireless communication unit (AP) 702 is an example of the first communication unit.

The millimeter-wave wireless communication unit (STA) 703 is realized by, for example, a program executed by the millimeter-wave wireless communication device 516-2 of FIG. 5A and the CPU 511 of FIG. 5A. The millimeter-wave wireless communication unit (STA) 703 functions as an STA (station) for millimeter-wave wireless communication and connects to a network cell for millimeter-wave wireless communication formed by another hopping node. Further, the millimeter-wave wireless communication unit (STA) 703 transmits / receives data by millimeter-wave wireless communication with another hopping node forming a network cell. The millimeter wave wireless communication unit (STA) 703 is an example of the second communication unit.

The storage unit 704 is realized by, for example, a program executed by the RAM 512 of FIG. 5A, the storage unit 514, and the CPU 511 of FIG. 5A, and temporarily receives data received by millimeter-wave wireless communication, for example. Functions as a buffer to store in. Further, the storage unit 704 stores various information such as access point information notified from the communication management device 403 and information of the edge node 402 connected to the network cell formed by the millimeter wave wireless communication unit (AP) 702. ..

The communication link state measuring unit 711 is realized by, for example, a program executed by the CPU 511 of FIG. 5A. The communication link state measuring unit 711 measures, for example, the communication link state of the millimeter wave radio communication unit (AP) 702, the hopping node 401 capable of communicating with the millimeter wave radio communication unit (STA) 703, and the edge node 402. The communication link state includes, for example, information such as received signal strength, throughput value, and packet loss rate. In the following description, the communication link state may be referred to as "communication quality".

The information collecting unit 712 is realized by, for example, a program executed by the CPU 511 of FIG. 5A, and scans (searches) other peripheral wireless communication terminals (hopping node 401, edge node 402) by millimeter-wave wireless communication. And collect information.

For example, the information collecting unit 712 uses the communication link state measuring unit 711 to acquire identification information (hopping node number, etc.) of other hopping nodes around the hopping node 401, and information such as the communication link state. Further, the information collecting unit 712 uses the communication link state measuring unit 711 to acquire the identification information (edge node number and the like) of the edge node around the hopping node 401 and the information such as the communication link state.

The information collected by the information collecting unit 712 is transmitted to the communication management device 403 by wireless LAN communication, for example, by the information transmitting unit 721.

The data transfer unit 713 is realized by, for example, a program executed by the CPU 511 of FIG. 5A. The data transfer unit 713 receives data received by one of the two millimeter-wave wireless communication units, the other, based on the instruction regarding the communication path notified from the communication management device 403 by wireless LAN communication. Transfer to another wireless communication terminal with the millimeter-wave wireless communication unit of. For example, the data transfer unit 713 uses the millimeter-wave wireless communication unit (STA) 703 to notify the data received by the millimeter-wave wireless communication unit (AP) 702 from the communication management device 403 by wireless LAN communication. Send to the wireless communication terminal of the transfer destination included in the instruction regarding.

The disconnection determination unit 714 is realized by, for example, a program executed by the CPU 511 of FIG. 5A, and determines disconnection of millimeter-wave wireless communication based on the communication link state measured by the communication link state measurement unit 711.

The edge node management unit (device management unit) 715 is realized by, for example, a program executed by the CPU 511 of FIG. 5A, and is connected to the network cell formed by the millimeter wave wireless communication unit (AP) 702. Manage. For example, the edge node management unit 715 registers the edge node 402 connected to the network cell formed by the millimeter wave wireless communication unit (AP) 702 in the hopping node 401, and notifies the registered edge node 402 of the IP address and the like. ..

The information transfer unit 716 is realized by, for example, a program executed by the CPU 511 of FIG. 5A, and relays information transmitted / received between the edge node 402 and the communication management device 403. For example, the information transfer unit 716 transfers the information received from the edge node 402 by millimeter wave wireless communication to the communication management device 403 by wireless LAN communication in response to the request from the edge node 402. Further, the information transfer unit 716 transfers the information received from the communication management device 403 by wireless LAN communication to the edge node 402 by millimeter wave wireless communication in response to the request from the communication management device 403.

The connection control unit 717 connects the millimeter-wave wireless communication unit to the other hopping node 401 notified from the communication management device 403 after the communication with the other hopping node 401 by the millimeter-wave wireless communication unit (STA) 703 is disconnected. (STA) 703 is connected by millimeter wave wireless communication.

The connection control unit 717 may be included in the communication management device 403. In this case, the millimeter-wave wireless communication unit (STA) 703 connects to another hopping node 401 notified from the connection control unit 717 of the communication management device 403 by millimeter-wave wireless communication.

The information transmission unit 721 is realized by, for example, a program executed by the CPU 511 of FIG. 5A, and transmits information to the communication management device 403 using the wireless LAN communication unit 701. For example, the information transmission unit 721 transmits information on peripheral wireless communication terminals collected by the information collection unit 712, a disconnection notification indicating that the millimeter-wave wireless communication has been disconnected, and the like to the communication management device 403 by wireless LAN communication. ..

The information receiving unit 722 is realized by, for example, a program executed by the CPU 511 of FIG. 5A, and receives information transmitted from the communication management device 403 using the wireless LAN communication unit 701. For example, the information receiving unit 722 receives control information such as an instruction regarding a communication path notified from the communication management device 403 by wireless LAN communication.

The registration request unit 723 is realized by, for example, a program executed by the CPU 511 of FIG. 5A. The registration request unit 723 transmits, for example, a registration request to the communication system 400 including information of peripheral wireless communication terminals collected by the information collection unit 712 by wireless LAN communication at the time of activation or the like.

(Functional configuration of edge node)
FIG. 8 is a diagram showing an example of the functional configuration of the edge node according to the embodiment. The edge node 402 has a millimeter-wave wireless communication unit (STA) 801, a data transmission unit 802, a data reception unit 803, a display control unit 804, an operation reception unit 805, a storage unit 806, and the like.

Preferably, the edge node 402 has a wireless LAN communication unit 811, an information transmission unit 812, an information reception unit 813, and the like.

The millimeter-wave wireless communication unit (STA) 801 is realized by, for example, a program executed by the millimeter-wave wireless communication device 526 of FIG. 5 (b) and the CPU 521 of FIG. 5 (b), and the millimeter-wave wireless communication STA is realized. To connect to a network cell for millimeter-wave wireless communication. The millimeter wave wireless communication unit (STA) 801 is an example of a fourth communication unit that performs millimeter wave wireless communication (first wireless communication).

The data transmission unit 802 is realized by, for example, a program executed by the CPU 521 of FIG. 5 (b), and content data such as video data, audio data, and files can be obtained by using the millimeter wave wireless communication unit (STA) 801. Transmit by millimeter wave wireless communication.

The data receiving unit 803 is realized by, for example, a program executed by the CPU 521 of FIG. 5B, and video data, audio data, and a file are used in millimeter-wave wireless communication using the millimeter-wave wireless communication unit (STA) 801. Receive content data such as.

The display control unit 804 is realized by, for example, a program executed by the CPU 521 of FIG. 5 (b), and the display device 527 of FIG. 5 (b) has an operation screen and a data reception unit 803.
Displays the video data etc. received by.

The operation receiving unit 805 is realized by, for example, a program executed by the CPU 521 of FIG. 5 (b), and receives a user's input operation or the like to the input device 528 or the like of FIG. 5 (b).

The storage unit 806 stores, for example, content data such as video data, audio data, and files received by the data reception unit 803.

The wireless LAN communication unit 811 is realized by, for example, a program executed by the wireless LAN communication device 525 of FIG. 5B and the CPU 521 of FIG. 5B, and communicates with the communication management device 403 or the like by wireless LAN communication. I do.

The information transmission unit 812 is realized by, for example, a program executed by the CPU 521 of FIG. 5B, and uses the wireless LAN communication unit 811 to transmit information to the communication management device 403 or the like by wireless LAN communication. For example, the edge node 402 transmits the request information or the like requesting the transmission of data by multi-hop communication to the communication management device 403 by using the information transmission unit 812.

The information receiving unit 813 is realized by, for example, a program executed by the CPU 521 of FIG. 5B, and receives control information or the like notified from the communication management device 403 by wireless LAN communication using the wireless LAN communication unit 811. do.

(Functional configuration of communication management device)
The communication management device 403 includes a wireless LAN communication unit 901, an information acquisition unit 902, a communication route management unit 903, a control information transmission unit 904, a hopping node management unit 905, an edge node management unit 906, a storage unit 907, a notification unit 908, and It has a classification unit 909 and the like.

The wireless LAN communication unit (fifth communication unit) 901 is realized by, for example, a program executed by the wireless LAN communication device 604 of FIG. 6 and the CPU 601 of FIG. 6B, and is a hopping node in wireless LAN communication. Communicates with 401, edge node 402, etc.

For example, the wireless LAN communication unit 901 has another hopping that can be connected from one hopping node 401 when one hopping node 401 changes from a specified state to another hopping terminal. It functions as a receiver that receives the search results searched for the terminal.

In addition, "when the communication state transitions from the specified state" includes, for example, the case where the hopping node 401 detects the deterioration (deterioration) of the communication quality of the millimeter wave wireless communication, or the case where the disconnection is detected. Is done. Further, in the following description, the hopping node 401 that detects the deterioration (decrease) or disconnection of the millimeter wave wireless communication and transmits the disconnection notification to the communication management device 403 is referred to as the "disconnected hopping node 401". There is.

The information acquisition unit (acquisition unit) 902 is realized by, for example, a program executed by the CPU 601 in FIG. 6B, and acquires information from a plurality of hopping nodes 401 by wireless LAN communication. For example, the information acquisition unit 902 transmits a scan request requesting information acquisition to a plurality of hopping nodes 401 by wireless LAN communication at a predetermined time interval or the like, and transmits the scan request from the plurality of hopping nodes 401. Acquires information on nearby wireless communication terminals.

The communication path management unit 903 is realized by, for example, a program executed by the CPU 601 in FIG. 6B, and is a communication that transfers data by multi-hop communication based on the information acquired by the information acquisition unit 902 by wireless LAN communication. Manage routes.

For example, the communication path management unit 903 identifies (or determines) the connection relationship between the devices by millimeter wave wireless communication as shown by the solid line 405 in FIG. 4 by using the information acquired by the information acquisition unit 902. The communication path of multi-hop communication is determined based on the connection relationship (or determined).

The control information transmission unit 904 is realized by, for example, a program executed by the CPU 601 of FIG. 6B, and transmits control information to the hopping node 401 or the like by wireless LAN communication.

The hopping node management unit 905 is, for example, the information of the hopping node 401 registered in the communication system 400 based on the information acquired by the information acquisition unit 902, which is realized by the program executed by the CPU 601 in FIG. 6B. To manage.

The edge node management unit 906 manages the information of the edge node 402 included in the communication system 400 based on the information acquired by the information acquisition unit 902, which is realized by the program executed by the CPU 601 in FIG. 6B, for example. do.

The storage unit 907 is realized by, for example, a program executed by the CPU 601 of FIG. 6B, a flash ROM 603, a RAM 602, and the like. The storage unit 907 stores various information such as a communication path managed by the communication path management unit 903 and information acquired by the information acquisition unit 902, for example.

When the classification unit 909 receives a disconnection notification including the scan result of another hopping node 401 from the hopping node 401 when transmitting data all at once by multi-hop communication, the other hopping node 401 is set to the first terminal group. And the second terminal group.

Here, the first terminal group includes a hopping node 401 to which a transmission source terminal that simultaneously transmits data in multi-hop communication and a communication path of multi-hop communication are connected. On the other hand, the hopping node 401 to which the communication path of the multi-hop communication is not connected to the transmission source terminal is classified into the second terminal group.

The notification unit 908 selects and disconnects a connection destination at which the data transmitted by the transmission source terminals all at once reaches all the hopping nodes 401 (or more hopping nodes 401) included in the communication system 400. Notify the hopping node 401.

For example, in the notification unit 908, when the disconnected hopping node 401 is connected to the source terminal and the communication path, that is, when it belongs to the first terminal group, the notification unit 908 of the hopping node 401 belonging to the second terminal group. Select the hopping node 401 to connect to.

On the other hand, in the notification unit 908, when the disconnected hopping node 401 is not connected to the transmission source terminal, that is, when it belongs to the second terminal group, the notification unit 908 of the hopping node 401 belonging to the first terminal group. Select the hopping node 401 to connect to.

For example, the notification unit 908 connects one or more hopping nodes 401 included in a terminal group different from the terminal group to which the disconnected hopping node 401 belongs among the first terminal group and the second terminal group. Select as the hopping node 401 of.

As an example, the notification unit 908 connects to one hopping node 401 having the best communication quality from one or more hopping nodes 401 included in a terminal group different from the terminal group to which the disconnected hopping node 401 belongs. Select as the hopping node 401 of.

Further, as another example, the notification unit 908 has the number of hops between one or more hopping nodes 401 included in a terminal group different from the terminal group to which the disconnected hopping node 401 belongs and the terminal of the transmission source. One hopping node 401 that minimizes (the number of relays) may be selected.

Further, the notification unit 908 notifies the disconnected hopping node 401 via the control information transmission unit 904 of the selected connection destination hopping node 401.

As a result, the connection control unit 717 of the disconnected hopping node 401 becomes one hopping node 401 included in the terminal group different from the terminal group to which the own terminal belongs among the first terminal group and the second terminal group. , Connect your terminal by millimeter wave wireless communication.

The notification unit 908 is an example of a transmission unit that transmits the classification result of the classification unit 909 to one hopping terminal whose communication state has changed from the specified state.

<Processing flow>
Subsequently, the flow of processing in the communication path switching method according to the present embodiment will be described.

[First Embodiment]
(Hopping node registration process)
FIG. 10 is a sequence diagram showing an example of the registration process of the hopping node according to the first embodiment. This process shows an example of the process when the hopping node 401 is started and registered as a hopping node in the communication management device 403. In the following sequence diagram, the broken line arrow represents communication by wireless LAN communication.

In step S1001, when the hopping node 401a is started by, for example, turning on the power or starting operation by the user, the processes after step S1002 are executed.

In step S1002, the hopping node 401a connects to the communication management device 403 by wireless LAN communication. For example, the wireless LAN communication unit 701 searches for the communication management device 403 by broadcast (or multicast), and requests the searched communication management device 403 to connect by wireless LAN communication.

When the hopping node 401a receives the response from the communication management device 403 in step S1003, the hopping node 401a scans another wireless communication terminal by millimeter-wave wireless communication in step S1004. For example, the information collecting unit 712 of the hopping node 401a uses the millimeter wave wireless communication unit (STA) 703 and the communication link state measuring unit 711 to provide information on other hopping nodes in the vicinity (for example, SSID, radio wave strength, etc.). ) Collect.

In step S1005, the hopping node 401a transmits a registration request requesting registration to the communication management device 403 by wireless LAN communication. This registration request includes scan results by the information gathering unit 712 (for example, SSIDs of other hopping nodes in the vicinity, radio field strength, etc.).

In step S1006, when the communication management device 403 receives the registration request from the hopping node 401a, the communication management device 403 executes a process of registering the hopping node 401a in the communication system 400. For example, the hopping node management unit 905 of the communication management device 403 stores information of other hopping nodes included in the registration request received from the hopping node 401 in the storage unit 907. Further, the hopping node management unit 905 determines the access point information (AP information) to be notified to the hopping node 401. This access point information includes, for example, information such as an SSID (Service Set Identifier), an encryption key, a communication channel, and an IP address used by the millimeter-wave wireless communication unit (AP) 702 of the hopping node 401.

In step S1007, the hopping node management unit 905 of the communication management device 403 selects the hopping node 401 to be connected to the hopping node 401a. For example, the hopping node management unit 905 connects from the hopping nodes 401 registered in the communication management device 403 based on the strength of the received radio wave included in the scan result, the number of connected wireless communication terminals, and the like. Select the previous hopping node 401.

If the hopping node to be connected can be selected in step S1007, the communication management device 403 executes the processes of steps S1008 to S1010. Here, assuming that the hopping node 401b is selected as the connection destination of the hopping node 401a, the following description will be given.

In step S1008, the hopping node management unit 905 of the communication management device 403 transmits a registration completion notification indicating that the registration is completed to the requesting hopping node 401a by wireless LAN communication. The registration completion notification includes, for example, information on the connection destination hopping node (for example, hopping node 401b) selected in step S1007, and access point information (AP information) determined in step S1006.

In step S1009, the millimeter-wave wireless communication unit (STA) 703 of the hopping node 401a connects to the connection destination hopping node 401b included in the registration completion notification by millimeter-wave wireless communication.

In step S1010, the millimeter-wave wireless communication unit (AP) 702 of the hopping node 401 uses the access point information included in the registration completion notification to connect the access point for millimeter-wave wireless communication and the DHCP (Dynamic Host Configuration Protocol) server. to start. For example, the millimeter-wave wireless communication unit (AP) 702 forms a network cell (BSS) for millimeter-wave wireless communication by using the SSID, encryption key, communication channel, IP address, etc. included in the notified access point information. ..

On the other hand, if the hopping node to be connected cannot be selected in step S1007, the communication management device 403 executes the process of step S1011.

In step S1011, the hopping node management unit 905 of the communication management device 403 transmits a registration completion notification indicating that the registration is completed to the requesting hopping node 401a by wireless LAN communication. In this case, the hopping node 401a starts over from the process of scanning another communication terminal by, for example, millimeter-wave wireless communication.

The hopping node 401a may notify the fact by a lamp or the like while another hopping node 401 to be connected cannot be found. As a result, the administrator, the installer, and the like can recognize that another hopping node 401 needs to be installed around the hopping node 401a.

In this way, the hopping node 401 connects to another hopping node 401 as soon as it is started. As a result, basically, a network is formed so that data can be transmitted to all wireless communication terminals at the same time by multi-hop communication by millimeter wave wireless communication.

However, if the situation is not improved and there is a hopping node 401 in which another hopping node 401 that can be connected by millimeter-wave wireless communication cannot be found, the communication management device 403 excludes the hopping node 401 from the communication path and wireless LAN. Send data by communication.

(About the disconnection judgment of the communication path)
FIG. 11 is a diagram for explaining the cutting determination according to the first embodiment. For example, as shown in FIG. 11, the hopping node B performing millimeter-wave wireless communication with the hopping node A continuously monitors the communication link state of the millimeter-wave wireless communication of the hopping node A, and performs millimeter-wave wireless communication. Judge disconnection (route switching).

At this time, there are a plurality of determination conditions for the hopping node 401 to determine the disconnection of the millimeter-wave wireless communication. for example,
1) When the millimeter-wave radio is disconnected or disconnected and a reconnection request is made but the connection cannot be made 2) The signal strength and throughput value of the millimeter-wave radio are below the threshold, or the packet error rate is above the threshold 3) Video -In the case of audio stream transfer, the loss rate of the video data packet in the transport application layer is equal to or higher than the threshold value. 4) In the case of video / audio stream transfer, the sequence number included in the packet header in the transport application layer. For example, when the next sequence number cannot be received for a certain period of time.

In the case of the condition 1), it is assumed that the hopping node B makes a reconnection request one or more times. Such processing is effective, for example, when an obstacle exists between the hopping node A and the hopping node B for a short period of time.

Regarding the condition of 2), as shown in FIG. 11, the threshold value is determined by combining one or more parameters (signal strength, throughput value, error rate, etc.) indicating communication quality. At this time, the moving average value may be used.

Regarding the condition of 3), for example, when transferring a video stream, the threshold value of the packet loss rate fluctuates depending on the video quality and quality required by the application.

The same applies to the condition of 4), which depends on, for example, the frame rate and resolution of video data.

Especially in the case of video stream transfer, it is difficult to make a switching judgment only by the condition 1) (millimeter wave wireless communication parameter), and if the condition 1) is satisfied, the secondary judgment is made under the conditions 3) and 4). When this condition is also satisfied, it is desirable to carry out the route switching process.

(Processing of hopping node)
FIG. 12 is a flowchart showing an example of processing of the hopping node according to the first embodiment. This process shows an example of the process executed when the hopping node 401 changes the communication path of the multi-hop communication and the millimeter-wave wireless communication is disconnected.

In step S1201, the information receiving unit 722 of the hopping node 401 receives a start notification from the communication management device 403 indicating that the multi-hop communication is started by the wireless LAN communication.

In step S1202, the communication link state measuring unit 711 of the hopping node 401 starts monitoring the communication quality of the millimeter wave wireless communication.

For example, in step S1203, the communication link state measuring unit 711 of the hopping node 401 has a communication quality such as a throughput value and an error rate of the millimeter wave wireless communication of the hopping node 401 to which the millimeter wave wireless communication unit (STA) 703 is connected. To measure.

In step S1204, the disconnection determination unit 714 of the hopping node 401 determines whether or not the measured communication quality is equal to or higher than the threshold value. When the measured communication quality is equal to or higher than the threshold value, the disconnection determination unit 714 returns the process to step S1203, and the communication link state measurement unit 711 continues to measure the communication quality. On the other hand, when the measured communication quality is not equal to or higher than the threshold value, the disconnection determination unit 714 shifts the process to step S1207.

Further, in step S1205, the communication link state measuring unit 711 of the hopping node 401 communicates with the millimeter wave radio communication of the hopping node 401 to which the millimeter wave radio communication unit (STA) 703 is connected in parallel with the processing of step S1203. Measure the received signal strength.

In step S1206, the disconnection determination unit 714 of the hopping node 401 determines whether or not the measured intensity of the received radio wave is equal to or greater than the threshold value. When the strength of the measured received radio wave is equal to or higher than the threshold value, the disconnection determination unit 714 returns the process to step S1205, and the communication link state measuring unit 711 continues to measure the strength of the received radio wave. On the other hand, when the measured intensity of the received radio wave is not equal to or higher than the threshold value, the disconnection determination unit 714 shifts the process to step S1207. The strength of the received radio wave of millimeter-wave wireless communication is another example of the communication quality of millimeter-wave wireless communication.

In step S1207, the information collecting unit 712 of the hopping node 401 scans another wireless communication terminal (hopping node 401) that can be connected by millimeter wave wireless communication using the millimeter wave wireless communication unit (STA) 703 (hopping node 401). search for.

In step S1208, the information transmission unit 721 of the hopping node 401 notifies the communication management device 403 of the disconnection notification including the scan result (search result) by wireless LAN communication.

In step S1209, when the connection control unit 717 of the hopping node 401 receives the information of the connection destination notified from the communication management device 403, the connection control unit (STA) 703 of the millimeter wave radio communication unit (STA) 703 is connected to the notified connection destination.

(Notification processing of connection destination)
FIG. 13 is a diagram showing an example of a network configuration when a disconnection occurs in the first embodiment. In FIG. 13, content data is simultaneously transmitted (for example, broadcast transmission) from an edge node (source) 402a, which is a wireless communication terminal of a transmission source, to other hopping nodes 401a to 401d and edge nodes 402b to 401e. And.

At this time, the content data transmitted from the edge node (source) 402a is sequentially multi-hop-transferred in the direction of the arrow of the "data transmission direction" in the figure, and reaches each wireless communication terminal.

Here, for example, it is assumed that the hopping node 401b detects the deterioration of the communication quality of the millimeter wave wireless communication with the hopping node 401c by the process shown in FIG. 12, and transmits the disconnection notification to the communication management device 403. At this time, the communication management device 403 executes, for example, the notification processing of the connection destination as shown in FIGS. 14A and 14B.

FIG. 14 is a flowchart showing an example of notification processing of the connection destination according to the first embodiment.

(Notification processing of connection destination 1)
FIG. 14A shows an example of the notification process of the connection destination executed by the communication management device 403.

In step S1411, when the information receiving unit 813 receives the disconnection notification transmitted from the hopping node 401, the communication management device 403 executes the processes after step S1412. The disconnection notification transmitted from the hopping node 401 includes the scan result of another hopping node 401 that can be connected from the hopping node 401, which is scanned by the hopping node 401.

FIG. 15A shows an image of an example of the scan result by the hopping node 401b shown in FIG. In the example of FIG. 15A, the scan result includes information such as “hopping node”, “SSID”, and “radio wave intensity”. Since the edge node 402 cannot be connected from the millimeter wave radio communication unit (STA) 703 of the hopping node 402, it is not included in the scan result.

The information of the "hopping node" is the information of the hopping node 401b that has been scanned (for example, the terminal name, the terminal ID, the node number, etc.). The information of "SSID" is information such as SSID that identifies another hopping node 401 searched by the hopping node 401b. The "radio wave strength" information is information indicating the strength of radio waves received from another hopping node 401.

In step S1412, the communication path management unit 903 of the communication management device 403 determines whether the content data transmitted by the edge node (source) 402a, which is the terminal of the transmission source, reaches all the hopping nodes 401.

As described above, the communication route management unit 903 manages the communication route for transferring data by multi-hop communication based on the information acquired by the information acquisition unit 902 in the wireless LAN communication. For example, the communication path management unit 903 manages the connection relationship between terminals by millimeter-wave wireless communication and the communication path of multi-hop communication as shown by the solid line in FIG. 13 using the information acquired by the information acquisition unit 902. are doing.

In the example of FIG. 13, the communication path management unit 903 determines that the content data does not reach the hopping nodes 401c and 401d due to the disconnection of the millimeter-wave wireless communication between the hopping node 401b and the hopping node 401c. can.

In step S1413, the communication management device 403 selects the hopping node 401 whose content data reaches all the hopping nodes 401 as the connection destination hopping node by connecting the hopping node 401b.

For example, in the example of FIG. 13, by connecting the hopping node 401b to the hopping node 401c or the hopping node 401d, the content data transmitted by the source terminal reaches all the hopping nodes 401.

Preferably, the communication path management unit 903 uses the hopping node 401 having the best communication quality as the connection destination among the hopping nodes 401c and 401d in which the content data transmitted by the transmission source terminal reaches all the hopping nodes 401. select.

For example, in the example of FIG. 15A, among the hopping nodes 401c and 401d in which the content data transmitted by the source terminal reaches all the hopping nodes 401, the strength of the received radio wave of the hopping node 401d is higher. Large (good communication quality). Therefore, the communication path management unit 903 selects the hopping node 401d as the connection destination of the disconnected hopping node 401b. The strength of the received radio wave is an example of information on communication quality, and other information on communication quality (for example, throughput value, error rate, etc.) may be used.

In step S1414, the notification unit 908 of the communication management device 403 notifies the hopping node 401b that has transmitted the disconnection notification of the information of the selected connection destination (for example, the hopping node 401d) by wireless LAN communication.

(Notification processing of connection destination 2)
FIG. 14B shows another example of the notification processing of the connection destination executed by the communication management device 403. The process shown in steps S1422 to S1426 of FIG. 14B is a specific example of the process shown in step S1413 of FIG. 14A.

In step S1421, when the information receiving unit 813 receives the disconnection notification transmitted from the hopping node 401, the communication management device 403 executes the processes after step S1422.

In step S1422, the classification unit 909 of the communication management device 403 acquires the scan result of another hopping node 401 that can be connected from the hopping node 401, which is included in the disconnection notification received by the information receiving unit 813.

In step S1423, the classification unit 909 uses the acquired scan result to connect other connectable hopping nodes 401 to the first terminal group to which the communication path is connected to the source terminal and the source terminal. And the second terminal group to which the communication path is not connected.

As described above, the communication path management unit 903 manages the information of the communication path of the multi-hop communication shown by the solid line in the network configuration shown in FIG. 13, for example.

FIG. 15B shows an image of an example of a communication route table that manages information on a communication route for multi-hop communication managed by the communication route management unit 903. In the example of FIG. 15B, the communication path table includes information such as "hopping node", "connection destination hopping node (AP)", and "connection with the source terminal".

The information of the "hopping node" is the information of the hopping node 401 registered in the communication management device 403 (for example, the terminal name, the terminal ID, the terminal number, etc.).

The information of the "connection destination hopping node (AP)" is the information of another hopping node 401 (for example, the terminal name, the terminal ID, the terminal number) to which the millimeter wave wireless communication unit (STA) 703 of each hopping node 401 is connected. Etc.). For example, in the example of FIG. 15B, the millimeter wave radio communication unit (STA) 703 of the hopping node 401a is connected to the millimeter wave radio communication unit (AP) 702 of the hopping node 401b by millimeter wave radio communication. It is shown. Further, it is shown that the millimeter-wave wireless communication unit (STA) 703 of the hopping node 401d is not connected to the access point of the other hopping node 401 by millimeter-wave wireless communication.

As for the information of "connection with the terminal of the source", the hopping node 401a to which the edge node (source) 402a, which is the terminal of the source of the content data, is directly connected is indicated by, for example, "○". There is.

The classification unit 909 uses, for example, a communication path table as shown in FIG. 15B, and when the millimeter-wave wireless communication of the hopping node 401b is disconnected, the classification unit 909 uses a communication path from each hopping node 401 to the source terminal. Determine if is connected.

FIG. 15C shows an image of the determination result of the communication path to the transmission source terminal in each hopping node 401.

For example, in FIG. 15B, since the hopping node 401a is directly connected to the terminal of the transmission source, the “communication path to the terminal of the transmission source” is “◯” in FIG. 15C.

Further, in FIG. 15B, since the hopping node 401b is connected to the AP of the hopping node 401b, the hopping node 401b can receive the content data via the hopping node 401a. Therefore, in FIG. 15C, the “communication path to the source terminal” of the hopping node 401b is “◯”.

On the other hand, in FIG. 15 (b), the hopping nodes 401c and 401d do not have a communication path to the hopping node 401a directly connected to the source terminal. Therefore, in FIG. 15 (c), "to the source terminal". Communication path "is" x ".

Further, the classification unit 909 can also obtain the number of hops (number of relays) from each hopping node 401 to the transmission source terminal by using the communication route table shown in FIG. 15 (b).

For example, the classification unit 909 uses the determination result as shown in FIG. 15 (c) to refer to the hopping nodes 401a, 401c, and 401d included in the scan result as shown in FIG. It is classified into a terminal group and a second terminal group.

For example, the hopping node 401a is classified into the first terminal group because the “communication path to the source terminal” is “◯” according to the determination result shown in FIG. 15 (c). On the other hand, the hopping nodes 401c and 401d are classified into the second terminal group because the "communication path to the source terminal" is "x" according to the determination result shown in FIG. 15 (c).

Here, returning to FIG. 14B, the explanation of the flowchart will be continued.

In step S1424, the notification unit 908 of the communication management device 403 determines whether the hopping node 401 that has transmitted the disconnection notification belongs to the first terminal group or the second terminal group. For example, in the example of FIG. 13, since the hopping node 401 to which the disconnection notification is transmitted is the hopping node 401b, the notification unit 908 refers to the determination result shown in FIG. 15 (c), and the hopping node 401b is the first terminal. Judge that it belongs to the group.

When the hopping node 401 that has transmitted the disconnection notification belongs to the first terminal group, the notification unit 908 shifts the process to step S1425. On the other hand, when the hopping node 401 that has transmitted the disconnection notification belongs to the second terminal group, the notification unit 908 shifts the process to step S1426.

After moving to step S1425, the notification unit 908 of the communication management device 403 selects the hopping node 401 to be connected from the other hopping nodes 401 classified into the second terminal group in step S1423.

As an example, the notification unit 908 uses the scan result shown in FIG. 15A to have a larger radio field intensity value (good communication quality) from the hopping nodes 401 classified into the second terminal group. Select one hopping node (eg, hopping node 401d).

Further, as another example, the notification unit 908 may select one or more hopping nodes 401 from other hopping nodes 401 classified into the second terminal group. In this case, the hopping node 401 that has transmitted the disconnection notification may selectively connect to the hopping node 401 having the best communication quality from among the one or more hopping nodes 401 notified from the communication management device 403.

In this case, each hopping node 401 may store, for example, the measurement history of the communication quality in the past millimeter-wave wireless communication in the storage unit 704 as shown in FIG. 16A. As a result, each hopping node 401 can select the hopping node 401 having the best communication quality from the one or more hopping nodes 401 notified from the communication management device 403.

In the example of FIG. 16A, an image of the measurement history of the communication quality stored in the storage unit 704 of the hopping node 401b is shown, and the hopping node 401d has a higher average throughput than the hopping node 401c. It is shown. Therefore, when the communication management device 403 notifies the hopping nodes 401c and 401d as the connection destination, the connection control unit 717 of the hopping node 401b connects to the hopping node 401d having a higher average throughput.

Here, the process returns to FIG. 14B, and the description of the flowchart is further continued.

When the process proceeds from step S1424 to step S1426, the notification unit 908 of the communication management device 403 selects the connection destination hopping node 401 from the other hopping nodes 401 classified into the first terminal group in step S1423.

As an example, the notification unit 908 uses the scan result as shown in FIG. 15A to have a higher radio wave intensity than the other hopping node 401 among the other hopping nodes 401 classified into the first terminal group. Select one hopping node 401 with a large value.

Further, as another example, as described in step S1425, the notification unit 908 selects one or more hopping nodes 401 from the other hopping nodes 401 classified into the first terminal group. Is also good.

In step S1427, the notification unit 908 of the communication management device 403 notifies the hopping node 401 that has transmitted the disconnection notification to the selected hopping node as the connection destination.

Upon receiving this notification, the hopping node 401 connects to the notified connection destination by millimeter wave wireless communication, for example, by the process shown in step S1209 of FIG.

At this time, the communication route management unit 903 of the communication management device 403 updates the communication route table as shown in FIG. 15B, for example, as the updated communication route table as shown in FIG. 16B. do. In the example of FIG. 16B, the connection destination of the hopping node 401b is changed to the hopping node 401d.

FIG. 17 is a diagram showing an example of a network configuration after route switching according to the first embodiment. This figure shows an example of the network configuration after the communication path is switched from the network configuration at the time of disconnection shown in FIG. 13 to the processing shown in FIGS. 12 and 14. In the example of FIG. 17, the hopping node 401b from which the millimeter-wave wireless communication with the hopping node 401c is disconnected is connected to the hopping node 401d. As a result, the content data simultaneously transmitted from the edge node (source) 402a reaches all the wireless communication terminals (hopping node 401 and edge node 402) again.

(Communication processing)
FIG. 18 is a sequence diagram showing an example of processing of the communication system according to the first embodiment. This process shows an example of the process of the entire communication system 400 corresponding to the process shown in FIGS. 12 and 15.

In steps S1801 and S1802, the hopping node 401b determines, for example, disconnection of millimeter-wave wireless communication with the hopping node 401c while transmitting data to the hopping node 401c, as shown in FIG. The hopping node 401b is an example of a first wireless communication terminal.

In step S1803, the information collecting unit 712 of the hopping node 401b scans (searches) another connectable wireless communication terminal with the millimeter wave wireless communication unit (STA) 703.

In step S1804, the information transmission unit 721 of the hopping node 401 notifies the communication management device 403 of the disconnection notification including the scan result by wireless LAN communication.

In step S1805, the communication management device 403 executes notification processing of the connection destination as shown in steps S1411 to S1413 of FIG. 14A or steps S1421 to S1426 of FIG. 14B. The communication management device 403 is an example of a second wireless communication terminal.

In step S1806, the notification unit 908 of the communication management device 403 notifies the hopping node 401b of the information of the connection destination (for example, the hopping node 401d) selected in step S1805 by wireless LAN communication.

In step S1807, when the connection control unit 717 of the hopping node 401b receives the information of the connection destination notified from the communication management device 403, the connection control unit 717 connects to the notified connection destination (for example, the hopping node 401d) by millimeter wave wireless communication. ..

In step S1808, the hopping node 401b and the hopping node 401d connected by millimeter-wave wireless communication mutually confirm the data reception status (or transmission status).

In step S1809, the hopping node 401b and the hopping node 401d receive (or transmit) unreceived (or untransmitted) data when there is unreceived (or untransmitted) data.

In step S1810, the hopping node 401d and the hopping node 401c mutually confirm the data reception status (or transmission status).

In step S1811, the hopping node 401d and the hopping node 401d receive (or transmit) unreceived (or untransmitted) data when there is unreceived (or untransmitted) data.

If the content data being transmitted is real-time streaming data, the processing of steps S1808 to S1811 is unnecessary.

As described above, according to the present embodiment, in a wireless communication system in which content data is simultaneously transmitted from a transmission source wireless communication terminal by multi-hop communication, the content data can be transmitted to a larger number of wireless communication terminals.

[Second Embodiment]
In the first embodiment, an example of processing when the hopping node 401 to be connected can be selected from the scan result of the disconnected hopping node 401 has been described. However, in reality, it may not be possible to select the hopping node 401 to be connected to. For example, there may be a case where the radio wave from another hopping node 401 does not reach due to a temporary obstacle or the like, or a case where the radio wave is too far to reach.

Therefore, in the second embodiment, for example, in step S1413 of FIG. 14A, an example of suitable processing when the hopping node to be selected cannot be selected will be described.

(Notification processing of connection destination)
FIG. 19 is a flowchart showing an example of notification processing of the connection destination according to the second embodiment. Of the processes shown in FIG. 19, the processes of steps S1411 to S1414 are the same as the processes of the first embodiment shown in FIG. 14 (a), and therefore, the differences from the first embodiment are mainly focused here. I will explain to.

In step S1901, the communication management device 403 determines in step S1413 whether or not the hopping node to be connected can be selected. If the hopping node to be connected can be selected, the communication management device 403 shifts the process to step S1414. On the other hand, if the hopping node to be connected cannot be selected, the communication management device 403 shifts the process to step S1902.

After moving to step S1902, the communication management device 403 requests a scan from all hopping nodes to which data does not reach.

As described above, the communication route management unit 903 of the communication management device 403 manages, for example, a communication route table for managing the communication route of multi-hop communication as shown in FIG. 15 (b). Therefore, the communication management device 403 identifies the hopping nodes 401c and 401d to which data does not reach, as shown in FIG. 15 (c), for example, when a disconnection occurs between the hopping node 401b and the hopping node 401c. can do.

In step S1903, the communication management device 403 selects, for example, a hopping node whose data reaches all the hopping nodes from the scan results received from the hopping nodes 401c and 401d where the data does not reach.

For example, in the network configuration shown in FIG. 13, in the first embodiment, a hopping node in which data reaches all hopping nodes is selected from the hopping node 401b in which disconnection occurs. However, in addition to this, for example, if any of the hopping nodes 401c and 401d that the data does not reach can be connected to any of the hopping nodes 401a, 401b and 401 that the data can reach, the data can reach all the hopping nodes. Become.

Therefore, in the present embodiment, when the hopping node 401 of the connection destination cannot be selected from the hopping node 401b in which the disconnection has occurred, the hopping node 401 of the connection destination is selected from the hopping nodes 401c and 401d to which the data does not reach.

For example, when the hopping node 401 to be connected is selected from the hopping node 401d, the communication management device 403 uses the other hopping node 401 scanned by the hopping node 401d as the first terminal group and the second terminal group described above. Classify into. Further, the communication management device 403 selects the hopping node 401 to be connected from among the classified first terminal group and the second terminal group, which are different from the terminal group to which the hopping node 401d belongs. do.

In step S1904, the communication management device 403 notifies the hopping node 401 whose connection destination is changed of the information of the connection destination hopping node 401.

For example, in the network configuration shown in FIG. 13, it is assumed that the hopping node 401a is selected as the connection destination of the hopping node 401d by the process of step S1903. In this case, for example, the communication route table as shown in FIG. 15B is updated as shown in FIG. 20.

In the example of FIG. 20, the connection destination of the hopping node 401b is changed to "None", and the connection destination of the hopping node 401d is changed to "Hopping node 401a". In this case, the communication management device 403 notifies the hopping node 401b and the hopping node 401d of the connection destination after the change.

FIG. 21 is a diagram showing an example of a network configuration after route switching according to the second embodiment. As shown in FIG. 21, when the hopping node 401d is connected to the hopping node 401a, the content data transmitted by the edge node (source) 402a is transmitted to all other wireless communication terminals.

(Communication system processing)
FIG. 22 is a sequence diagram showing an example of processing of the communication system according to the second embodiment. This process shows an example of the process of the entire communication system 400 corresponding to the process shown in FIG. Of the processes shown in FIG. 22, the processes of steps S1801 to S1804 are the same as the processes according to the first embodiment shown in FIG. 18, and therefore, the differences from the first embodiment will be mainly described here. I do.

In step S2001, the communication management device 403 executes the notification processing of the connection destination as shown in steps S1411 to S1413 of FIG. 14A or steps S1421 to S1426 of FIG. 14B. However, here, it is assumed that the hopping node 401 to which the hopping node 401b is connected cannot be selected.

In step S2002, the notification unit 908 of the communication management device 403 notifies the hopping node 401b that has transmitted the disconnection notification that the connection destination hopping node 401 does not exist by wireless LAN communication.

In steps S2003 and S2005, the communication management device 403 requests a hopping node (for example, hopping nodes 401c, 401d) to which the content data from the transmission source terminal does not reach, to scan by wireless LAN communication.

In steps S2004 and S2006, the hopping nodes 401c and 401d each transmit the scan result to the communication management device 403 by wireless LAN communication.

In step S2007, the communication management device 403 selects the hopping node 401 whose connection destination is changed and the hopping node of the connection destination so that the data reaches all the hopping nodes 401 from the received scan result. This process corresponds to the process of step S1903 in FIG. 19 described above.

In step S2008, the notification unit 908 of the communication management device 403 notifies the hopping node (hopping node 401d) whose connection destination is changed, which is selected in step S2007, of the information of the connection destination hopping node (hopping node 401a). ..

In step S2009, the connection control unit 717 of the hopping node 401d connects to the connection destination (for example, the hopping node 401a) notified from the communication management device 403 by millimeter wave wireless communication.

In step S2010, the hopping node 401d and the hopping node 401a connected by millimeter-wave wireless communication confirm the data reception status (or transmission status) with each other.

In step S2011, the hopping node 401d and the hopping node 401a receive (or transmit) unreceived (or untransmitted) data when there is unreceived (or untransmitted) data.

In step S2012, the hopping node 401d and the hopping node 401c mutually confirm the data reception status (or transmission status).

In step S2013, the hopping node 401d and the hopping node 401c receive (or transmit) unreceived (or untransmitted) data when there is unreceived (or untransmitted) data.

As described above, according to the present embodiment, the content data can be transmitted to more wireless communication terminals even when the connection destination hopping node 401 cannot be selected in the disconnected hopping node 401b.

[Third Embodiment]
In the first and second embodiments, the communication management device 403 connects the hopping node 401b based on the radio field strength received from another hopping node 401 included in the scan result as shown in FIG. 15A, for example. The previous hopping node 401 was selected.

In the third embodiment, an example of processing in which the communication management device 403 selects the hopping node 401 to be connected based on the throughput value of the millimeter-wave wireless communication with the other hopping node 401 will be described. ..

(Communication system processing)
FIG. 23 is a sequence diagram showing an example of processing of the communication system according to the third embodiment. An example of processing when the hopping node 401 of the connection destination is selected based on the throughput value of another hopping node 401 is shown.

Of the processes shown in FIG. 23, the processes shown in steps S1801 to S1804 and steps S1806 to S1809 are the same as the processes of the first embodiment shown in FIG. The differences will be mainly explained.

In step S2301, the communication management device 403 selects a candidate for the hopping node 401 to be connected to the hopping node 401b by using the scan result included in the disconnection notification received from the hopping node 401b.

For example, when a disconnection notification including a scan result as shown in FIG. 15A is received, the hopping nodes 401c and 401d to which the hopping node 401b is not connected by millimeter wave wireless communication are connected to the hopping node 401 as a connection destination. Select as a candidate.

At this time, the hopping node 401c disconnected by the hopping node 401b may be excluded from the candidates because the disconnection determination has just been performed. Here, the following description will be given assuming that the hopping nodes 401c and 401d are candidates for the hopping node 401 to be connected.

In step S2302, the communication management device 403 notifies the hopping node 401b that has transmitted the disconnection notification by wireless LAN communication to the list of the selected connection destination candidates.

In steps S2303 to S2308, the hopping node 401b sequentially connects millimeter-wave wireless communication to each of the notified candidates for the hopping node 401 to be connected to, and the communication quality of the millimeter-wave wireless communication (here, here,). Measure the throughput value).

For example, in step S2303, the connection control unit 717 of the hopping node 401b connects to the hopping node 401c by millimeter wave wireless communication using the millimeter wave wireless communication unit (STA) 703.

In step S2304, the communication link state measuring unit 711 of the hopping node 401b measures the throughput value in the millimeter-wave wireless communication with the hopping node 401c, for example, by transmitting and receiving measurement data.

In steps S2305 and S2306, the connection control unit 717 of the hopping node 401b disconnects the millimeter-wave wireless communication with the hopping node 401c and connects to the hopping node 401d by millimeter-wave wireless communication.

In step S2307, the communication link state measuring unit 711 of the hopping node 401b measures the throughput value of the millimeter wave wireless communication with the hopping node 401d.

In step S2308, the connection control unit 717 of the hopping node 401b disconnects the millimeter-wave wireless communication with the hopping node 401d.

In step S2309, the information transmission unit 721 of the hopping node 401b transfers the measurement result of the throughput value measured with each hopping node 401 included in the list of connection destination candidates by wireless LAN communication to the communication management device 403. Send to.

In step S2310, the communication management device 403 selects the hopping node 401 to which the hopping node 401b is connected based on the measurement result of the throughput value received from the hopping node 401b. This process is basically the same as the notification process of the connection destination shown in FIG. 14 (a) or FIG. 14 (c), but when the hopping node 401 of the connection destination is selected, the received signal strength is changed. The difference is that the throughput value is used instead (or in addition).

For example, the classification unit 909 of the communication management device 403 sets the other hopping nodes 401 included in the scan result as shown in FIG. 15A into the above-mentioned first terminal group and the second terminal group. Classify.

Further, the notification unit 908 of the communication management device 403 is selected from among the classified first terminal group and second terminal group, which are different from the terminal group to which the hopping node 401b that has transmitted the disconnection notification belongs. , Select the hopping node 401 to connect to.

At this time, the notification unit 908 selects the hopping node 401 having the highest throughput value from the hopping nodes (for example, hopping nodes 401c and 401d) included in the terminal group different from the terminal group to which the hopping node 401b belongs. ..

Here, for example, when the hopping node 401d is selected as the connection destination hopping node, the processing as shown in steps S1806 to S1809 is executed.

As described above, the communication quality value of the millimeter-wave wireless communication used when the communication management device 403 selects the hopping node 401 to be connected is not limited to the strength of the received radio wave, but the throughput value is used. May be. Further, the communication quality value of the millimeter wave wireless communication used when the communication management device 403 selects the hopping node 401 to be connected is, for example, another communication quality value such as a bit error rate or a frame error rate. It may be used.

(About communication management equipment)
In the description so far, the communication management device 403 has been described as, for example, a dedicated device having a hardware configuration as shown in FIG. However, the present invention is not limited to this, and the communication management device 403 may be, for example, a wireless communication terminal having the hardware configuration of the hopping node 401 as shown in FIG. 5A.

As a result, for example, the hopping node 401 can be activated as the communication management device 403 and configure the communication system 400 when there is no communication management device 403 in the vicinity. Further, the communication management device 403 having the hardware configuration of the hopping node 401 can participate in multi-hop communication as one of the hopping nodes 401.

FIG. 24 is a sequence diagram showing an example of a hopping node activation process according to an embodiment.

When the hopping node A is activated in step S2401, in step S2402, the hopping node A determines whether or not the communication management device 403 is already operating by inquiring about the presence or absence of the communication management device 403 by wireless LAN communication. do.

In step S2403, if there is no response from the communication management device 403 within a predetermined time, the hopping node A is activated as the communication management device 403. At this time, the hopping node A may realize only the functional configuration of the communication management device 403 as shown in FIG. 9, or further realizes the functional configuration of the hopping node 401 as shown in FIG. 7. It may be.

When the hopping node B is activated in step S2404, the hopping node B inquires about the presence or absence of the communication management device 403 by wireless LAN communication in step S2405.

In step S2406, the hopping node A already activated as the communication management device 403 responds to the hopping node B by wireless LAN communication with information indicating that the hopping node A is operating as the communication management device 403.

In step S2407, when the hopping node B receives a response from the communication management device 403 within a predetermined time, the hopping node B is activated as the hopping node 401, and for example, the processing after step S1001 in FIG. 10 is executed.

By the above processing, the hopping node 401 automatically functions as the communication management device 403 even when there is no dedicated communication management device 403, and the communication system 400 can be configured.

400 Communication system (wireless communication system)
401 Hopping node (hopping terminal, wireless communication terminal)
402 Edge node (edge terminal)
403 Communication management device (communication management terminal)
701 Wireless LAN communication unit (third communication unit)
702 mmWave wireless communication unit (AP) (first communication unit)
703 Millimeter-wave wireless communication unit (STA) (second communication unit)
704 Storage unit 801 Millimeter-wave wireless communication unit (STA) (fourth communication unit)
901 Wireless LAN communication unit (fifth communication unit, receiving unit)
902 Information acquisition department (acquisition department)
908 Notification section (transmitter section)
909 Classification Department

Japanese Unexamined Patent Publication No. 2009-0946228

Claims (10)

A wireless communication system that includes a plurality of hopping terminals and a communication management device, and simultaneously transmits data from a source terminal to another terminal by multi-hop communication .
The hopping terminal is
A first communication unit that functions as an access point for millimeter-wave wireless communication and forms a network cell for millimeter-wave wireless communication.
A second communication unit that functions as a millimeter-wave wireless communication station and connects to a network cell formed by another hopping terminal.
A third communication unit that performs wireless LAN communication with the communication management device,
A data transfer unit that transmits the data received by one of the first communication unit and the second communication unit to another terminal by the other communication unit.
Other hopping that can be connected by the second communication unit when the deterioration or disconnection of the communication quality of the millimeter wave wireless communication by the second communication unit is detected while transmitting the data to the other terminal. An information transmission unit that sends a disconnection notification including terminal information to the communication management device, and
A connection control unit that connects the second communication unit to the connection destination hopping terminal notified from the communication management device.
Have,
The communication management device is
A wireless LAN communication unit that performs wireless LAN communication with the hopping terminal,
Among the hopping terminals, the first hopping terminal that detects the deterioration or disconnection of the communication quality of the millimeter wave wireless communication issues the disconnection notification including the information of the second hopping terminal that can be connected by the millimeter wave wireless communication. The acquisition department to acquire and
Based on the information of the second hopping terminal acquired by the acquisition unit, the second hopping terminal is used with the first terminal group to which the communication path is connected to the terminal of the transmission source and the transmission source. A classification unit that classifies terminals into a second group of terminals that are not connected to a communication path,
The second hopping terminal included in a terminal group different from the terminal group to which the first hopping terminal belongs among the first terminal group and the second terminal group classified by the classification unit. A notification unit that notifies the first hopping terminal as the connection destination hopping terminal, and
A wireless communication system. The wireless communication system according to claim 1, wherein the communication management device has a communication path management unit that manages the communication path of the multi-hop communication. The notification unit
When the first hopping terminal is connected to the source terminal and the communication path, one or more of the second hopping terminals included in the second terminal group are selected and the first hopping terminal is selected. Notify the hopping terminal of
When the first hopping terminal is not connected to the source terminal and the communication path, one or more of the second hopping terminals included in the first terminal group are selected and the first hopping terminal is selected. The wireless communication system according to claim 1 or 2 , which notifies the hopping terminal of the above. The notification unit selects the second hopping terminal having the best communication quality from the second hopping terminal included in the first terminal group or the second terminal group, and the first one. The wireless communication system according to claim 3, which notifies the hopping terminal . The wireless communication system according to claim 4, wherein the communication quality includes a value of a received signal strength or a throughput in the first hopping terminal . The wireless communication system according to claim 4 or 5, wherein the communication quality includes a value of a received signal strength or a throughput in the second hopping terminal . The notification unit selects the second hopping terminal having the smallest number of relays to the source terminal from the second hopping terminals included in the first terminal group or the second terminal group. The wireless communication system according to claim 3, wherein the first hopping terminal is notified. The first hopping terminal is
It has a storage unit that temporarily stores the data, and has a storage unit.
Claims 1 to 7, wherein the connection control unit transmits / receives the data that has not been transmitted / received to / from the connection destination hopping terminal after connecting the second communication unit to the connection destination hopping terminal. The wireless communication system according to any one of the above. The wireless communication system includes a fourth communication unit that performs millimeter-wave wireless communication, and includes an edge terminal connected to one network cell among the network cells, according to any one of claims 1 to 8. The wireless communication system described. It is a method of switching a communication path in a wireless communication system that includes a plurality of hopping terminals and a communication management device and simultaneously transmits data from a source terminal to another terminal by multi-hop communication.
The hopping terminal
The first communication process that functions as an access point for millimeter-wave wireless communication and forms the network cell for millimeter-wave wireless communication.
A second communication process that functions as a millimeter-wave wireless communication station and connects to a network cell formed by another hopping terminal.
A third communication process for performing wireless LAN communication with the communication management device,
Of the first communication process and the second communication process, the data transfer process of transmitting the data received in one of the communication processes to the other terminal in the other communication process.
Other hopping that can be connected by the second communication process when the deterioration or disconnection of the communication quality of the millimeter wave wireless communication by the second communication process is detected while transmitting the data to the other terminal. Information transmission processing for transmitting a disconnection notification including terminal information to the communication management device, and
The connection control process for connecting to the connection destination hopping terminal notified from the communication management device in the second communication process, and the connection control process.
And run
The communication management device
Wireless LAN communication processing that performs the wireless LAN communication with the hopping terminal,
Among the hopping terminals, the first hopping terminal that detects the deterioration or disconnection of the communication quality of the millimeter wave wireless communication issues the disconnection notification including the information of the second hopping terminal that can be connected by the millimeter wave wireless communication. The acquisition process to acquire and
Based on the information of the second hopping terminal acquired in the acquisition process, the second hopping terminal is the first terminal group to which the communication path is connected to the terminal of the transmission source, and the transmission source. Classification processing to classify into a second terminal group to which the communication path is not connected to the terminal, and
The second hopping terminal included in a terminal group different from the terminal group to which the first hopping terminal belongs among the first terminal group and the second terminal group classified by the classification process . , Notification processing for notifying the first hopping terminal as the hopping terminal of the connection destination,
How to switch the communication path.

Images