JP7114952B2 - Communication system and method of controlling communication system - Google Patents

Description

The present invention relates to a communication system and a method of controlling a communication system.

IEEE (Institute of Electrical and Electronics Engineers) 802.11ad is known as a standard for wireless communication that performs high-speed data transmission using the millimeter wave (60 GHz) band, which has high straightness of radio waves and a relatively narrow communication range. .

Also, in a multi-hop network divided into a plurality of clusters, a technique is known for reducing the difference in cluster size by changing the cluster head candidates of each cluster based on the distance between the cluster head candidates. (See Patent Document 1, for example).

A communication system that performs multi-hop communication of data using a plurality of relay terminals that form a subnetwork by millimeter wave wireless communication and a connection terminal that connects to the subnetwork by millimeter wave wireless communication is conceivable. In such a communication system, since radio waves with strong directivity are used for communication between terminals, the number of terminals that can be connected to each subnetwork is limited, and the number of terminals connected to each subnetwork is uneven. If there is, the connectivity and convenience of the communication system may decrease.

In addition, in such a communication system, since the relay terminal and the connection terminal have different terminal configurations, for example, the technique disclosed in Patent Document 1 cannot be applied as it is.

Embodiments of the present invention have been made in view of the above problems, and data are transmitted using a relay device that forms a subnetwork with radio waves having directivity and a connection terminal that is connected to the subnetwork. Improve the connectivity and convenience of multi-hop communication systems.

In order to solve the above problems, a communication system according to an embodiment of the present invention is a communication system including a plurality of relay terminals, a plurality of connection terminals, and a communication management device , wherein the relay terminals are:
A first communication unit that functions as an access point for the first wireless communication and forms a subnetwork for the first wireless communication, and another relay terminal that functions as a station for the first wireless communication and forms a relay terminal. a second communication unit that connects to the subnetwork; a third communication unit that performs second wireless communication with the communication management device; data received by one of the first communication unit and the second communication unit based on an instruction relating to a communication path for wireless communication, and transmitting data received by the other communication unit to another relay terminal; or a data transfer unit that transfers data to the edge node; and a connection terminal management unit that manages the connection terminal connected to the subnetwork formed by the first communication unit; a fourth communication unit that functions as one wireless communication station and is connected to the subnetwork; the communication management device includes a fifth communication unit that performs the second wireless communication with the relay terminal; an information acquiring unit for acquiring the number of the connected terminals connected to each relay terminal from the plurality of relay terminals using the second wireless communication; and the number of the connected terminals acquired by the information acquiring unit. is equal to or greater than a threshold, the connection terminal connected to the relay terminal having the largest number of connection terminals is determined using the second wireless communication. and a relay terminal management unit that transmits control information for instructing execution of processing for reducing the number of terminals.

According to one embodiment of the present invention, the connectivity and convenience of a communication system that performs multi-hop communication of data using a relay device that forms a subnetwork with radio waves having directivity and a connection terminal that connects to the subnetwork. can be improved.

1 is a diagram (1) for explaining a millimeter wave wireless communication system according to an embodiment; FIG. FIG. 2 is a diagram (2) for explaining a millimeter wave wireless communication system according to an embodiment; FIG. 3 is a diagram for explaining an example of beamforming according to an embodiment; FIG. It is a figure which shows the structural example of the communication system which concerns on one Embodiment. FIG. 4 is a diagram illustrating an example of a hardware configuration of a hopping node and an edge node according to one embodiment; FIG. It is a figure which shows the example of the hardware constitutions of the communication management apparatus which concerns on one Embodiment. FIG. 4 is a diagram illustrating an example of a functional configuration of a hopping node according to one embodiment; FIG. FIG. 4 is a diagram illustrating an example of a functional configuration of an edge node according to one embodiment; FIG. It is a figure which shows the example of functional structure of the communication management apparatus which concerns on one Embodiment. FIG. 11 is a sequence diagram illustrating an example of hopping node registration processing according to an embodiment; FIG. 7 is a sequence diagram illustrating an example of edge node registration processing according to an embodiment; FIG. 11 is a flowchart illustrating an example of processing when a hopping node is activated according to one embodiment; FIG. FIG. 7 is a sequence diagram illustrating an example of edge node count acquisition processing according to the first embodiment; It is a figure which shows the example of the information which the communication system which concerns on one Embodiment manages. FIG. 7 is a sequence diagram illustrating an example of edge node selection processing according to the first embodiment; FIG. 7 is a sequence diagram illustrating an example of edge node connection processing according to the first embodiment; FIG. 4 is a diagram illustrating an example of a network configuration after changing a connection destination according to the first embodiment; FIG. FIG. 12 is a sequence diagram illustrating an example of connection destination change processing according to the second embodiment;

Embodiments of the present invention will be described below with reference to the accompanying drawings.

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

A millimeter-wave wireless communication system is a wireless communication system that performs high-speed data transmission using a millimeter-wave (60 GHz) band, in which radio waves are highly rectilinear and have a relatively narrow communication range. Here, the following description will be given assuming that the millimeter wave wireless communication system is a wireless communication system conforming to IEEE (Institute of Electrical and Electronics Engineers) 802.11ad. Note that IEEE802.11ad is an example of a millimeter-wave wireless communication system according to this embodiment.

(network configuration)
A millimeter-wave wireless communication system that conforms to IEEE802.11ad communicates using the millimeter-wave (60 GHz) band, which has a relatively narrow communication range with high straightness of radio waves, and uses a wide band of 2.16 GHz per channel. This enables high-speed data communication.

In addition, since the propagation loss of radio waves increases in the millimeter wave band, in order to increase the antenna gain in the millimeter wave wireless communication system, a beamforming technique is used in which radio waves are transmitted and received by narrowing the beam direction of the radio waves. 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 communication protocol of the TDMA (Time Division Multiple Access) method 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 AP (Access Point) forms a network cell called 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. 1(a) shows an example of a one-to-one network configuration in which an AP 110 forming a BSS 100, which is a network cell of a millimeter wave wireless communication system, and a STA (station) 120 communicate by millimeter wave wireless communication 130. showing. In the example of FIG. 1(a), the AP 110 manages time slots in the TDMA protocol and, for example, transmits beacon frames at predetermined time intervals.

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

In IEEE802.11ad, in addition to the network configurations shown in FIGS. 1A and 1B, a PBSS (Personal Basic Service Set) 200 formed by a coordinator device called PCP and A network configuration called In PBSS200, STAs 120-1 to 120-3 can communicate with other STAs via PCP201, and can communicate with other STAs without PCP201.

(Time slot configuration)
FIG. 2(b) is a diagram illustrating an example of time slots according to one embodiment. FIG. 2(b) shows allocation of time slots in the TDMA protocol managed by AP 110. FIG. The time slot of the TDMA protocol managed by the AP 110 includes BHI (Beacon Header Interval) and DTI (Data Transfer Interval), as shown in FIG. 2(b).

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

BTI is the period during which AP 110 transmits a beacon frame. A-BFT is the beamforming training period. ATI is a period for transmitting and receiving management information, control information, etc. between AP 110 and STAs 120-1 to 120-3.

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

CBAP is a contention period allocated for the AP 110 and a plurality of STAs 120 to contend and communicate. SP is a dedicated time period allocated for communication between AP 110 and one STA 120 .

The AP 110 transmits as many beacon frames as the number of antenna sectors, which are multiple beam patterns formed by the AP 110, in the BTI. On the other hand, STAs 120-1 to 120-3 receive all beacon frames transmitted from the AP by setting omnidirectional antennas or semi-omnidirectional antennas, and send information indicating the antenna sector with the best reception quality to AP 110. provide feedback. As a result, AP 110 can ascertain whether each STA 120-1 to 120-3 should communicate using the antenna sector.

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

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

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

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

In RXSS, a beamforming training sequence in the opposite direction to TXSS is executed, and when TXSS and RXSS are completed, radio waves can be transmitted and received between AP 110 and STA 120 by millimeter wave wireless communication.

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

FIG. 4 is a diagram illustrating a configuration example of a communication system according to one embodiment. The communication system 400 includes, for example, multiple 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, "hopping node 401" is used when indicating an arbitrary hopping node among the plurality of hopping nodes 401-1 to 401-5. Also, when indicating an arbitrary edge node among the one or more edge nodes 402-1 to 402-7, "edge node 402" is used.

A hopping node (relay terminal) 401 includes 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. and a communication device. Note that millimeter wave wireless communication is an example of first wireless communication that performs multi-hop communication using radio waves having directivity. Also, wireless LAN communication is an example of second wireless communication having a wider communication range than first wireless communication.

A plurality of hopping nodes 401-1 to 401-5 form different sub-networks (BSS) in millimeter wave wireless communication using the first communication unit. For example, in FIG. 4, hopping node 401-1 forms subnetwork 406-1 and hopping node 401-2 forms subnetwork 406-2. Hopping node 401-3 forms subnetwork 406-3, and other hopping nodes similarly form subnetwork.

Also, the hopping node 401 can connect to a sub-network formed by other hopping nodes using the second communication unit. In the example of FIG. 4, hopping node 401-2 uses a second communication unit (STA) to connect subnetwork 406-1 formed by the first communication unit (AP) of hopping node 401-1 to a millimeter network. It can be connected by wave wireless communication. Also, the hopping node 401-1 is connected to the subnetwork 406-3 formed by the first communication unit (AP) of the hopping node 401-3 by millimeter wave wireless communication through the second communication unit (STA). be able to. Similarly, the hopping node 401-3 connects to the sub-network formed by the first communication unit (AP) of the hopping node 401-4 by millimeter wave wireless communication through the second communication unit (STA). can be done.

Furthermore, 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 can perform wireless LAN communication with the communication management device 403 using the third communication unit. can. The access point for wireless LAN communication may be the communication management device 403, or may use another access point. Here, the following description is given assuming that the access point for wireless LAN communication is the communication management device 403 .

An edge node (connection terminal) 402 is a communication device that includes a fourth communication unit that functions as an STA for millimeter-wave wireless communication, and connects to one subnetwork among a plurality of subnetwork formed by the edge node 402. . In the example of FIG. 4, edge nodes 402-1 to 402-3 use a fourth communication unit (STA) to connect subnetwork 406- formed by the first communication unit (AP) of hopping node 401-1. connected to 1.

Also, although not essential, the edge node 402 may further have a communication unit that performs wireless LAN communication. For example, the dashed line 404 in FIG. 4 indicates the connection relationship between devices through wireless LAN communication, and it is indicated that the edge node 402-6 can communicate with the communication management device 403 through wireless LAN communication. . Similarly, multiple hopping nodes 401-1 to 401-5 are shown to be able to communicate with the communication management device 403 via wireless LAN communication.

In the above configuration, each hopping node 401 uses a second communication unit (STA) to collect information of peripheral communication devices through millimeter wave wireless communication, and transmits the collected information to the communication management device through wireless LAN communication. 403.

A communication management device (communication management terminal) 403 uses information received from each hopping node 401 via wireless LAN communication to establish a connection relationship between devices by millimeter-wave wireless communication, as indicated by a solid line 405 in FIG. 4, for example. to manage. Further, when multi-hop communication is performed by millimeter wave wireless communication, the communication management device 403 determines a data communication route based on the connection relationship between the devices, and instructs the hopping nodes 401 on the communication route regarding the communication route. is transmitted by wireless LAN communication.

The hopping node 401 transfers the content data received by the millimeter wave wireless communication to another communication device using the millimeter wave wireless communication based on the communication path instruction notified by the wireless LAN communication from the communication management device 403. .

As described above, in the present embodiment, the hopping node 401 has two millimeter wave communication units, and content data is transferred using the two millimeter wave communication units, so the delay time of data transfer can be reduced. .

<Hardware configuration>
(Hardware configuration of hopping node)
FIG. 5A shows an example of the hardware configuration of the hopping node 401. FIG. The hopping node 401 includes, 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, 516-2, lamp 517, bus 518 and the like.

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

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

The wireless LAN communication device 515 is, for example, a wireless communication device for performing wireless LAN communication conforming to standards such as IEEE802.11a/b/g/n/ac. Control) section, communication control section, etc.

The millimeter wave wireless communication devices 516-1 and 516-2 are, for example, wireless communication devices for performing millimeter wave wireless communication conforming to standards such as IEEE802.11ad. Including the control unit, etc.

The lamp 517 is, for example, a light-emitting element for displaying the operating state of the hopping node 401 by changing color, lighting/blinking, or the like. A bus 518 is connected to each component described above and transmits address signals, data signals, 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. As shown in FIG. The edge node 402 has, 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. Among them, the configuration 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. is the same as the configuration of each unit described in the hopping node 401, so the description is omitted here. omitted.

The display device 527 is a display device such as a liquid crystal display that displays a display screen. The input device 528 is, for example, an input device such as a touch panel or a keyboard that receives user input operations.

Note that the configuration of the edge node 402 shown in FIG. 5 is an example, and the edge node 402 may not have the wireless LAN communication device 525 .

(Hardware configuration of communication management device)
FIG. 6 is a diagram illustrating an example of a hardware configuration of a communication management device according to one embodiment; The communication management device 403 has, 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 device that implements each function of the communication management device 403 by executing a program stored in the flash ROM 603 or the like. A RAM 602 is a volatile memory used as a work area or the like for the CPU 511 . The flash ROM 603 is a rewritable non-volatile memory that can retain programs and data even when the power is turned off.

A wireless LAN communication device 604 is a wireless communication device for performing wireless LAN communication. A bus 605 is connected to each component described above and transmits address signals, data signals, various control signals, and the like.

<Function configuration>
Next, the functional configuration of each device will be described.

(Functional configuration of hopping node)
FIG. 7 is a diagram illustrating an example of a functional configuration of a hopping node according to one embodiment; A hopping node (relay terminal) 401 has 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. The hopping node 401 also 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 communication management unit 717, and the like. Furthermore, the hopping node 401 has an information transmitting unit 721, an information receiving unit 722, a registration requesting unit 723, and the like.

The wireless LAN communication unit (third communication unit) 701 is implemented by, for example, a program or the like executed by the wireless LAN communication device 515 in FIG. 5A and the CPU 511 in 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 implemented by, for example, programs executed by the millimeter wave wireless communication device 516-1 in FIG. 5A and the CPU 511 in FIG. 5A. A millimeter wave wireless communication unit (AP) 702 functions as an AP (access point) for millimeter wave wireless communication and forms a subnetwork (BSS) for millimeter wave wireless communication. In addition, a millimeter wave wireless communication unit (AP) 702 transmits and receives data to and from millimeter wave wireless communication STAs connected to the formed sub-network. Note that the millimeter wave wireless communication unit (AP) 702 is an example of a first communication unit.

The millimeter wave wireless communication unit (STA) 703 is implemented by, for example, programs executed by the millimeter wave wireless communication device 516-2 in FIG. 5(a) and the CPU 511 in FIG. 5(a). A millimeter wave wireless communication unit (STA) 703 functions as a millimeter wave wireless communication STA (station) and connects to a millimeter wave wireless communication sub-network formed by other hopping nodes. Also, a millimeter wave wireless communication unit (STA) 703 transmits and receives data to and from other hopping nodes forming a subnetwork by millimeter wave wireless communication. Note that the millimeter wave wireless communication unit (STA) 703 is an example of a second communication unit.

The storage unit 704 is realized by, for example, programs executed by the RAM 512, the storage unit 514, and the CPU 511 of FIG. functions as a buffer for storing Further, the storage unit 704 stores various information such as access point information notified from the communication management device 403 and information on the edge node 402 connected to the subnetwork 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 in FIG. 5(a). The communication link state measurement unit 711 measures the communication link state of millimeter wave wireless communication. The communication link state includes, for example, received signal strength, communication throughput, packet loss rate, SQ (Signal Quality) value, and other information. In the following description, the communication link state may be referred to as "communication quality".

The information collecting unit 712 is implemented by, for example, a program executed by the CPU 511 in FIG. to collect information.

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

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

The data transfer unit 713 is realized by, for example, a program or the like executed by the CPU 511 in FIG. 5(a). The data transfer unit 713 transfers the content data received by millimeter wave wireless communication (first wireless communication) to others by millimeter wave wireless communication based on the instruction regarding the communication path notified by the communication management apparatus 403 by wireless LAN communication. communication device.

Preferably, when the millimeter wave wireless communication unit (STA) 703 receives content data, the data transfer unit 713 uses the millimeter wave wireless communication unit (AP) 702 to transmit the received content data to another communication device (hopping). node 401 and edge node 402).

Further, when the millimeter wave wireless communication unit (AP) 702 receives the content data, the data transfer unit 713 uses the millimeter wave wireless communication unit (STA) 703 or the millimeter wave wireless communication unit (AP) 702 to Transfer the content data to another communication device.

The disconnect determination unit 714 is realized by, for example, a program executed by the CPU 511 in FIG.

An edge node management unit (connection terminal management unit) 715 is implemented by, for example, a program executed by the CPU 511 in FIG. 402 is managed. For example, the edge node management unit 715 registers the edge node 402 connected to the subnetwork 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. .

Further, the edge node management unit 715, in response to receiving the control information transmitted from the communication management device 403, instructs one or more edge nodes connected to the hopping node 401 to connect to another hopping node 401. Sends instruction information to instruct the change of

Note that the control information transmitted from the communication management device 403 includes an instruction to execute processing (adjustment) to reduce the number of edge nodes connected to the hopping node 401, the number of hopping nodes 401 to be reduced, and the hopping node to be reconnected. 401 priority, and other information.

The instruction information that the edge node management unit 715 transmits to the edge node 402 includes, for example, information about the priority of the hopping node 401 to be reconnected to.

The information transfer unit 716 is implemented, for example, by a program executed by the CPU 511 in FIG. For example, in response to a request from the edge node 402, the information transfer unit 716 transfers 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 a request from the communication management device 403, the information transfer unit 716 transfers information received from the communication management device 403 via wireless LAN communication to the edge node 402 via millimeter wave wireless communication.

The communication management unit 717 is implemented by, for example, a program executed by the CPU 511 in FIG. For example, the hopping node 401 checks whether there is a usable communication management device 403 in the vicinity at the time of startup or the like. can be executed.

The information transmission unit 721 is realized by, for example, a program executed by the CPU 511 in FIG. For example, the information transmitting unit 721 transmits the information on the peripheral communication devices collected by the information collecting unit 712, a disconnection notification indicating that the millimeter wave wireless communication has been disconnected, and the like to the communication management apparatus 403 via wireless LAN communication.

The information receiving unit 722 is implemented by, for example, a program executed by the CPU 511 in FIG. 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 via wireless LAN communication.

The registration request unit 723 is realized by, for example, a program executed by the CPU 511 in FIG. 5(a). The registration requesting unit 723 transmits a registration request to the communication system 400 including the information of the peripheral communication devices collected by the information collecting unit 712 by wireless LAN communication, for example, at the time of activation.

(Functional configuration of edge node)
FIG. 8 is a diagram illustrating an example of a functional configuration of an edge node according to one embodiment; An edge node (connection terminal) 402 includes 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 a communication link state measurement unit 807. etc.

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.

A millimeter wave wireless communication unit (STA) 801 is implemented by, for example, a program or the like executed by the millimeter wave wireless communication device 526 in FIG. 5B and the CPU 521 in FIG. and connect to the mmWave wireless subnetwork. Note that 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 in FIG. Transmit by millimeter wave wireless communication.

The data receiving unit 803 is implemented by, for example, a program executed by the CPU 521 in FIG.

The display control unit 804 is implemented by, for example, a program executed by the CPU 521 in FIG.
display the received video data.

The operation reception unit 805 is realized by, for example, a program executed by the CPU 521 shown in FIG. 5B, and receives user's input operation and the like to the input device 528 shown in FIG. 5B.

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

The communication link state measuring unit 807 is realized by, for example, a program executed by the CPU 521 in FIG. 5B, the millimeter wave wireless communication unit (STA) 801, or the like. The communication link state measurement unit 807 measures the communication link state (communication quality) such as the received signal strength of millimeter wave wireless communication, communication throughput, packet loss rate, SQ (Signal Quality) value, and the like.

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

The information transmission unit 812 is implemented by, for example, a program executed by the CPU 521 in FIG. For example, the edge node 402 uses the information transmitting unit 812 to transmit request information or the like requesting transmission of data by multi-hop communication to the communication management device 403 .

The information receiving unit 813 is implemented by, for example, a program executed by the CPU 521 in FIG. 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 determination unit 903, a control information transmission unit 904, a hopping node management unit 905, an edge node management unit 906, a storage unit 907, and a priority determination unit. 908, etc.

The CPU 601 of the communication management device 403 functions as a control unit that implements each of the functional configurations described above by executing a predetermined program. Also, the communication management device 403 is an example of a terminal management device.

A wireless LAN communication unit (fifth communication unit) 901 is realized, for example, by a program or the like executed by the wireless LAN communication device 604 in FIG. 6 and the CPU 601 in FIG. 401, communicates with the edge node 402 and the like.

The information 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 through wireless LAN communication. For example, the information acquisition unit 902 transmits a scan request requesting acquisition of information to each hopping node 401 via wireless LAN communication, and acquires information of peripheral communication devices transmitted from each hopping node 401 . Information on the peripheral communication devices includes, for example, information such as the number of edge nodes 402 connected to each hopping node 401 .

The communication route determining unit 903 is implemented by, for example, a program executed by the CPU 601 in FIG. 6B, and transfers content data through multi-hop communication based on the information acquired by the information acquiring unit 902 through wireless LAN communication. Manage communication paths.

For example, the communication path determination unit 903 uses the information acquired by the information acquisition unit 902 to identify (or determine) the connection relationship between devices by millimeter wave wireless communication, as indicated by the solid line 405 in FIG. A communication route for multi-hop communication is determined based on the connection relationship obtained.

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

A hopping node management unit (relay terminal management unit) 905 is implemented by, for example, a program executed by the CPU 601 in FIG. hopping node 401 and its information.

The edge node management unit 906 is implemented by, for example, a program executed by the CPU 601 in FIG. to manage.

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

The priority determination unit 908 is realized by, for example, a program executed by the CPU 601 in FIG. determine the priority as For example, when the priority of the hopping node 401 is notified from the communication management device 403 or the hopping node 401, the edge node 402 preferentially connects to the hopping node 401 having a higher priority.

<Process flow>
Next, the flow of the control method for the communication system 400 according to this embodiment will be described.

(Hopping node registration process)
FIG. 10 is a sequence diagram illustrating an example of hopping node registration processing according to an embodiment. This processing shows an example of processing for registering the hopping node 401 in the communication management device 403 when the hopping node 401 is activated. In the following sequence diagrams, dashed arrows indicate communication by wireless LAN communication.

In step S1001, when the hopping node 401 is activated by, for example, turning on the power or by a user's activation operation, the processes from step S1002 onward are executed.

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

In steps S1003 and S1004, when the hopping node 401 receives a response from the communication management device 403, it scans (searches for) other communication devices by millimeter wave wireless communication. For example, the information collection unit 712 of the hopping node 401 uses the millimeter wave wireless communication unit (STA) 703 and the communication link state measurement unit 711 to collect information on other hopping nodes 401 that can be connected.

In step S1005, the hopping node 401 transmits a registration request requesting registration in the communication system 400 to the communication management apparatus 403 via wireless LAN communication. For example, the information transmitting unit 721 of the hopping node 401 uses the wireless LAN communication unit 701 to send a registration request including information (eg, identification information, received signal strength, etc.) of the other hopping nodes 401 collected by the information collecting unit 712. and transmits it to the communication management device 403 .

In step S<b>1006 , upon receiving the registration request from the hopping node 401 , the communication management device 403 registers the hopping node 401 in the communication system 400 . For example, the hopping node management unit 905 of the communication management device 403 stores information on other hopping nodes included in the registration request received from the hopping node 401 in the storage unit 907 . Hopping node management section 905 also determines access point information to be notified to hopping node 401 . This access point information includes, for example, information such as SSID (Service Set Identifier), encryption key, communication channel, IP address, etc. used by millimeter wave wireless communication unit (AP) 702 of hopping node 401 . Note that the SSID, IP address, and the like are examples of identification information that identifies a subnetwork for millimeter-wave wireless communication.

In step S1007, the communication management apparatus 403 transmits a registration completion notification including the registration number and access point information to the hopping node 401 by wireless LAN communication. For example, the control information transmission unit 904 of the communication management device 403 uses the wireless LAN communication unit 901 to send a registration completion notification including the access point information determined by the hopping node management unit 905 and the registration number generated at the time of registration. , to the requesting hopping node 401 .

In step S<b>1008 , the hopping node 401 uses the access point information notified from the communication management device 403 to activate an AP (access point) for millimeter wave wireless communication and a DHCP (Dynamic Host Configuration Protocol) server. For example, the millimeter wave wireless communication unit (AP) 702 of the hopping node 401 uses the SSID, encryption key, communication channel, IP address, etc. included in the notified access point information to access the millimeter wave wireless communication subnetwork (BSS). ).

By the above processing, the hopping node 401 forms a millimeter wave wireless communication sub-network, and the communication management device 403 stores the information of the hopping node 401 in the storage unit 907 .

In this way, by designating the SSID of the subnetwork formed by hopping node 401, communication management device 403 uses the SSID of hopping node 401 to determine whether or not it has been registered in communication system 400. will be able to

(edge node registration process)
FIG. 11 is a sequence diagram illustrating an example of edge node registration processing according to an embodiment. This processing shows an example of processing for the communication management device 403 to register the edge node 402 in the communication system 400 .

In step S1101, it is assumed that the edge node A 402a having the wireless LAN communication unit 811 is activated by, for example, a user's operation.

In step S1102, the edge node A 402a uses the millimeter wave wireless communication unit (STA) 801 to connect to the hopping node 401 by millimeter wave wireless communication.

In step S1103, the millimeter wave wireless communication unit (AP) 702 of the hopping node 401 permits the connection of the edge node A 402a and notifies the edge node A 402a of the IP address.

In step S1104, the edge node A 402a transmits a registration request including the IP address notified from the hopping node 401 to the communication management device 403 via wireless LAN communication.

In step S1105, the communication management device 403 registers the edge node A 402a in the communication system 400 upon receiving the registration request from the edge node A 402a. For example, the edge node management unit 906 of the communication management device 403 associates the IP address included in the registration request received by the edge node A 402a with the identification information of the edge node A 402a and stores it in the storage unit 907 .

Edge node A 402 a is registered in communication system 400 by the above processing. If the edge node 402 does not have the wireless LAN communication unit 811, for example, edge node registration processing is performed by the processing after step S1111.

In step S1111, the edge node B 402b that does not have the wireless LAN communication unit 811 is activated by, for example, a user's operation.

In step S1112, the edge node B 402b uses the millimeter wave wireless communication unit (STA) 801 to connect to the hopping node 401 by millimeter wave wireless communication.

In step S1113, the millimeter wave wireless communication unit (AP) 702 of the hopping node 401 permits the connection of the edge node B 402b and notifies the edge node B 402b of the IP address.

In step S1114, the edge node B 402b transmits a registration request including the IP address notified from the hopping node 401 to the hopping node 401 by millimeter wave wireless communication.

In step S1115, upon receiving the registration request sent from the edge node B 402b to the communication management apparatus 403, the information transfer unit 716 of the hopping node 401 transfers the received registration request to the communication management apparatus 403 via wireless LAN communication. .

In step S<b>1116 , upon receiving the registration request from the edge node B 402 b via the hopping node 401 , the communication management device 403 registers the edge node B 402 b in the communication system 400 .

Thus, the edge node 402 may communicate with the communication management device 403 via the hopping node 401 .

(Processing when starting a hopping node)
The hopping node 401 can execute the functions of the communication management device 403 if there is no communication management device 403 nearby at the time of activation.

FIG. 12 is a flowchart illustrating an example of processing when a hopping node is activated according to one embodiment. The hopping node 401 executes the processing shown in FIG. 12, for example, at startup.

In step S1201, the hopping node 401 scans the communication management device 403 by wireless LAN communication.

In step S1202, the hopping node 401 branches the process depending on whether or not the communication management apparatus 403 is found (whether or not the communication management apparatus 403 is present) by scanning by wireless LAN communication.

If the communication management device 403 is present, the hopping node 401 shifts the process to step S1207. On the other hand, if there is no communication management device 403, the hopping node 401 shifts the processing to step S1203.

After shifting to step S<b>1203 , the hopping node 401 activates the communication management unit 717 and causes the hopping node 401 to execute the function of the communication management device 403 . Thereby, the communication management unit 717, for example, the information acquisition unit 902, the communication route determination unit 903, the control information transmission unit 904, the hopping node management unit 905, the edge node management unit 906 included in the communication management device 403 shown in FIG. , priority determination unit 908 and the like.

In step S1204, the hopping node 401 scans for other communication devices using millimeter wave wireless communication. For example, the information collection unit 712 of the hopping node 401 uses the millimeter wave radio communication unit (STA) 703 and the communication link state measurement unit 711 to collect information on other connectable hopping nodes 401 in the vicinity.

In step S1205, the registration request unit 723 of the hopping node 401 requests the registration of the hopping node 401 to the communication management unit 717 functioning as a communication management device.

In step S1206, registration requesting section 723, upon receiving the registration completion notification from communication managing section 717, causes the process to proceed to step S1210.

On the other hand, when moving from step S1202 to step S1207, the hopping node 401 scans for other communication devices by millimeter wave wireless communication.

In step S1208, the registration requesting unit 723 requests the communication management apparatus 403 to register the hopping node 401 through wireless LAN communication.

In step S1209, the registration requesting unit 723 determines whether or not a registration completion notification has been received from the communication management apparatus 403 within a predetermined time.

If the registration completion notification is not received from the communication management device 403 within the predetermined time, the registration requesting unit 723 returns the process to step S2201 and executes the same process again. On the other hand, if the registration completion notification is received from the communication management device 403 within the predetermined time, the registration requesting unit 723 shifts the process to step S1210.

In step S1210, the millimeter wave wireless communication unit (AP) 702 of the hopping node 401 uses the access point information included in the registration completion notification received from the communication management apparatus 403 to activate the access point for millimeter wave wireless communication.

In this way, the hopping node 401 can execute the function of the communication management device 403 and the function of the hopping node 401 when there is no communication management device 403 nearby.

<Change processing of connection destination of edge node>
Next, an example of processing for changing the hopping node 401 to which the edge node 402 is connected when the number of edge nodes 402 connected to each hopping node 401 is uneven will be described.

[First Embodiment]
An access point (subnetwork) for millimeter wave wireless communication formed by the hopping node 401 has a smaller number of connectable terminals than an access point such as a general wireless LAN. Therefore, when the number of edge nodes 402 connected to the access point formed by the hopping node 401 increases, the number of other hopping nodes 401 connectable to the access point decreases, and the degree of freedom of communication paths may decrease.

Moreover, when the number of edge nodes 402 connected to the access point formed by the hopping node 401 increases, the newly activated edge node 402 may not be able to connect to the access point formed by the hopping node 401 .

In this way, if the number of edge nodes 402 connected to the subnetwork formed by each hopping node 401 is uneven, the connectivity and convenience of the communication system may deteriorate.

In the present embodiment, a control method for the communication system 400 that improves the connectivity and convenience of the communication system 400 by eliminating imbalance in the number of edge nodes 402 connected to the subnetwork formed by each hopping node 401. explain.

(Acquisition processing of the number of edge nodes)
FIG. 13 is a sequence diagram illustrating an example of processing for acquiring the number of edge nodes according to the first embodiment. This process is executed by the communication management device 403 at, for example, a certain time, a predetermined time interval, a predetermined event, or the like.

Here, as an example, the communication system 400 has a network configuration as shown in FIG. 4, and the following description will be given.

In step S1301, the information acquisition unit 902 of the communication management apparatus 403 requests the hopping node 401-1 to acquire the number of connected edge nodes 402 via wireless LAN communication.

In step S1302, the edge node management unit 715 of the hopping node 401-1 acquires the number of edge nodes 402 connected to the subnetwork formed by the millimeter wave wireless communication unit (AP) 702 of the hopping node 401-1. .

In step S1303, the information transmitting unit 721 of the hopping node 401-1 transmits the obtained number of edge nodes to the communication management device 403 via wireless LAN communication.

Through the above processing, the information acquisition unit 902 of the communication management device 403 can acquire the number of edge nodes connected to the hopping node 401-1.

Similarly, the information acquisition unit 902 of the communication management device 403 connects to each hopping node 401 from each of the other hopping nodes 401-2 to 401-5 registered in the communication system 400 in steps S1304 to S1315. get the number of edge nodes 402 that are Further, the information acquisition unit 902 stores information on the number of edge nodes acquired from the hopping nodes 401-1 to 401-5 in the storage unit 907. FIG.

FIG. 14A shows an image of an example of edge node number information acquired by the information acquisition unit 902 and stored in the storage unit 907 through the above process. In the example of FIG. 14A, the edge node count information stores information such as “IP address”, “MAC address”, and “number of edge nodes” for each hopping node 401 .

“IP address” is the IP address of hopping node 401 , and “MAC address” is the MAC address of hopping node 401 . Note that the IP address and MAC address are examples of identification information that identifies the hopping node 401 .

“Number of edge nodes” is information indicating the number of edge nodes connected to the subnetwork formed by the hopping node 401 .

In step S1316 of FIG. 13, the edge node management unit 906 of the communication management device 403 uses the edge node number information as shown in FIG. is compared with a first predetermined threshold. If the difference between the maximum and minimum numbers of edge nodes exceeds the first threshold, the edge node management unit 906 starts edge node selection processing as shown in FIG. 14, for example.

For example, in FIG. 14A, the maximum number of edge nodes is "3" and the minimum number is "0", so the difference between the maximum and minimum numbers of edge nodes is "3". Further, when the difference "3" between the maximum value and the minimum value of the number of edge nodes exceeds a first threshold value (for example, "2"), the edge node management unit 906 selects the edge node shown in FIG. Let the process begin.

If the difference "3" between the maximum and minimum numbers of edge nodes does not exceed a first threshold value (for example, "2"), the edge node management unit 906 terminates the process.

(Selection processing of edge nodes)
FIG. 15 is a sequence diagram illustrating an example of edge node selection processing according to the first embodiment. This process is executed, for example, when it is determined in step S1316 in FIG. 13 that the difference between the maximum and minimum numbers of edge nodes exceeds the first threshold.

In step S1501, the priority determining unit 908 of the communication management device 403 determines the connection priority of each hopping node 401 based on information on the number of edge nodes as shown in FIG. 14(a), for example.

For example, in the information on the number of edge nodes shown in FIG. Determine connection priority.

Here, the hopping node 401 with a small number of "edge nodes" is preferentially connected to the edge node 402. Therefore, the connection priority is set so that the hopping node 401 with a small "number of edge nodes" has a higher priority. to decide.

For example, in FIG. 14A, the priority determining unit 908 sets the connection priority of the hopping node 401-3, which has the smallest "number of edge nodes", to be the highest (for example, "1"). Also, the priority determination unit 908 sets the connection priority of the hopping nodes 401-2 and 401-5, which have the next smallest number of edge nodes after the hopping node 401-3, to the connection priority of the hopping node 401-3. Set low (eg "2"). Furthermore, priority determining section 908 sets the connection priority of hopping node 401-4, which has a smaller “number of edge nodes” than hopping nodes 401-2 and 401-5, to the connection priority of hopping nodes 401-2 and 401-5. degree) (eg "3").

In step S1502, the edge node management unit 906 of the communication management device 403 uses the control information transmission unit 904 to reduce the number of edge nodes 402 connected to the hopping node 401-1 having the maximum “number of edge nodes”. Send a reduction request (control information) requesting This reduction request includes, for example, priority information as shown in FIG.

FIG. 14(b) shows an image of an example of priority information transmitted by the communication management device 403. FIG. This priority information is created by, for example, the priority determination unit 908 or the edge node management unit 906, and information such as "SSID" and "connection priority" is stored for each hopping node 1401. FIG.

“SSID” is an example of identification information that identifies a millimeter-wave wireless communication subnetwork. The “connection priority” is the connection priority determined by the priority determining unit 908, and the edge node 402 gives priority to the hopping node 401 having a smaller “connection priority” value (higher priority). connect to.

The "SSID" includes, for example, a common character string (eg, "Milli-Wave-BSS") and an index number (or character string) that differs for each hopping node, as shown in FIG. 14(b). .

Depending on the OS, the hopping node 401 to be connected cannot be selected using the BSSID. Therefore, if the SSID of the hopping node 401 is shared, the hopping node 401 to be connected may not be selected. On the other hand, if the SSIDs of the hopping nodes 401 are completely different, there is a possibility that they will be connected to an external network. Select hopping node 401 .

In step S1503, the information collection unit 712 of the hopping node 401-1 requests the edge node 402-1 connected to the hopping node 401-1 to obtain communication quality (eg, SQ value) through millimeter wave wireless communication. Send a get request to request. The SQ value is an example of information indicating the communication quality of millimeter wave wireless communication, and information indicating other communication quality such as communication throughput, received signal strength, bit error rate, packet error rate, etc. is used. It can be.

In step S1504, the communication link state measuring unit 807 of the edge node 402-1 measures the communication quality of millimeter wave wireless communication.

In step S1505, the data transmission unit 802 of the edge node 402-1 transmits information indicating the measured communication quality of millimeter wave wireless communication to the hopping node 401-1 by millimeter wave wireless communication.

Through the above processing, the information collection unit 712 of the hopping node 401-1 acquires information indicating the communication quality of millimeter wave wireless communication with the edge node 402-1 connected to the hopping node 401-1. can be done.

Similarly, in steps S1506 to S1511, the information collecting unit 712 of the hopping node 401-1 receives millimeter wave wireless Collect information indicating the communication quality of communication.

Preferably, the information collecting unit 712 uses the collected information to create communication quality information as shown in FIG. 14(c), for example. In the example of FIG. 14(c), the communication quality information stores "IP address", "MAC address", and "SQ value" information for each edge node 402 connected to the hopping node 401-1. It is

“IP address” and “MAC address” are examples of identification information for identifying the edge node 402 . The “SQ value” is an example of information indicating the communication quality of millimeter wave wireless communication, and the larger the value, the better the communication quality.

In step S1512, the edge node management unit 715 of the hopping node 401-1 selects one of the edge nodes 402-1 to 402-3 connected to the hopping node 401-1, which edge node has worse communication quality than the other edge nodes. Select 402.

At this time, the number of edge nodes 402 to be selected follows the "number of terminals of edge nodes 402 to be reduced" included in the reduction request received in step S1502. Here, the following description is given assuming that the number of edge nodes 402 to be selected is "1".

In the example of FIG. 14(c), the edge node manager 715 selects the edge node 402-3 with the smallest SQ value.

In step S1513, the edge node management unit 715 of the hopping node 401-1 transmits instruction information instructing the edge node 402-3 selected in step S1512 to change the connection destination to another hopping node 401. FIG. This instruction information includes, for example, priority information as shown in FIG. 14(b).

In step S1514, the millimeter wave wireless communication unit (STA) 801 of the edge node 402-3 that has received the instruction information disconnects the millimeter wave wireless communication connected to the hopping node 401-1.

Preferably, when the edge node 402-3 cuts off the millimeter wave wireless communication with the hopping node 401-1, for example, it cuts off without maintaining the TCP (Transmission Control Protocol) communication connection. That is, the edge node 402-3 does not use the TCP keep-alive function. Also, when the edge node 402-4 is connected to another hopping node 401 by millimeter wave radio communication, it is connected by TCP communication.

In step S1515, the millimeter wave radio communication unit (STA) 801 of the edge node 402-3 scans for other hopping nodes connectable by millimeter wave radio communication.

FIG. 14(d) shows an image of an example of the scanning result by the edge node 402-3. In the example of FIG. 14(d), the scan result includes the SSID for identifying each subnetwork connectable from the edge node 402-3, and the received signal strength information of the radio wave received from each subnetwork.

In step S1516, the edge node 402-3 selects the destination hopping node 401 using, for example, the priority information shown in FIG. 14(b) and the scan result shown in FIG. select.

For example, the edge node 402-3 selects the hopping nodes 401-2 to 401-5, which are connection destination candidates, in order from the hopping node 401 having the highest connection priority, if the value of the received signal strength is equal to or greater than the second threshold. determine whether there is If the value of the received signal strength of hopping node 401 is equal to or greater than the second threshold, edge node 402-3 selects hopping node 401 as the hopping node to which it is connected.

For example, assume that the second threshold is "-60 dBm". In this case, the edge node 402-3 determines whether or not the received signal strength of the hopping node 401-3 whose connection priority is "1" in FIG. 14(b) is "-60 dBm" or more.

In the examples of FIGS. 14(b) and 14(d), the received signal strength of hopping node 401-3 is "-55 dBm", which is greater than the second threshold. 3 is selected as the hopping node 401 to be connected.

Here, for example, when the received signal strength of the hopping node 401-3 is less than the second threshold, the edge node 402-3 connects the hopping nodes 401-2 and 401-5 with the connection priority of "2". is greater than or equal to the second threshold. In this case, since the received signal strength of hopping node 401-2 is "-70 dBm" and the received signal strength of hopping node 401-5 is "-58 dBm", hopping node 401-5 is selected as connection destination hopping node 401. .

Here, the following description is given assuming that the edge node 402-3 has selected the hopping node 401-3 as the hopping node 401 to be connected.

The edge node 402-3 performs edge node connection processing as shown in FIG. 16, for example, on the selected hopping node 401-3.

(Edge node connection processing)
FIG. 16 is a sequence diagram illustrating an example of edge node connection processing according to the first embodiment.

In step S1601, the millimeter wave wireless communication unit (STA) 801 of the edge node 402-3 connects to the hopping node 401-3 selected in step S1516 of FIG. 15 by millimeter wave wireless communication.

In step S1602, the millimeter wave wireless communication unit (AP) 702 of the hopping node 401-3 permits the connection of the edge node 402-3 and notifies the edge node 402-3 of the IP address.

In step S1603, the edge node 402-3 transmits a registration request including the IP address notified from the hopping node 401-3 to the hopping node 401-3 by millimeter wave wireless communication.

In step S1604, the information transfer unit 716 of the hopping node 401-3 transfers the registration request received from the edge node 402-3 to the communication management device 403 via wireless LAN communication.

In step S1605, upon receiving the registration request from the edge node 402-3 via the hopping node 401-3, the communication management device 403 registers the edge node 402-3 with the communication system 400. FIG.

By the above processing, for example, the network configuration as shown in FIG. 4 is changed to the network configuration as shown in FIG.

FIG. 17 is a diagram illustrating an example of a network configuration after changing a connection destination according to the first embodiment; In the example of FIG. 17, the connection destination of the edge node 402-3 that was connected to the hopping node 401-1 in FIG. 4 is changed to the hopping node 401-3. As a result, the number of edge nodes 402 connected to each hopping node 401-1 to 401-5 becomes 1 or 2, and the bias in the number of edge nodes 402 connected to each hopping node 401-1 to 401-5 is reduced. It can be seen that it has been improved.

As described above, according to the present embodiment, the connectivity and convenience of the communication system 400 that performs multi-hop communication using the hopping node 401 that forms a subnetwork with radio waves having directivity and the edge node 402 that connects to the subnetwork. can improve sexuality.

[Second embodiment]
In the first embodiment, an example of processing when changing the hopping node 401 to which the edge node 402 is connected under the control of the communication management device 403 has been described. In the second embodiment, an example of processing in which the edge node 402 autonomously changes the hopping node 401 to which it is connected when, for example, the communication quality of the millimeter wave wireless communication of the hopping node 401 deteriorates will be described. do.

Note that the functional configurations of the hopping node 401, the edge node 402, and the communication management device 403 may be the same as the functional configurations of the devices according to the first embodiment shown in FIGS.

(connection destination change processing)
FIG. 18 is a sequence diagram illustrating an example of connection destination change processing according to the second embodiment.

In step S1801, it is assumed that the edge node 402 is communicating with the hopping node 401-1 by millimeter wave wireless communication, for example. Note that the edge node 402 continuously measures the communication quality (for example, communication throughput) of the millimeter-wave wireless communication while communicating with the hopping node 401-1, and for example, measures the communication quality as shown in FIG. 14(e). It is assumed that the measurement results are managed.

In step S1802, when edge node 402 detects deterioration of communication quality during millimeter wave wireless communication with hopping node 401-1, edge node 402 starts processing from step S1803.

For example, edge node 402
1) When the received signal strength is less than the threshold of the received signal strength for more than a predetermined number of times in succession 2) When the communication throughput is less than the threshold of the communication throughput 3) The bit error rate is less than the bit error rate 4) If the packet error rate exceeds the threshold of the packet error rate, it is determined that the communication quality has deteriorated if any of the conditions are met.

In step S1803, the edge node 402 disconnects millimeter wave wireless communication with the hopping node 401-1.

In step S1804, the edge node 402 scans for other hopping nodes 401 connectable by millimeter wave wireless communication. As a result, the edge node 402 acquires a scan result as shown in FIG. 14(d), for example.

In step S1805, the edge node 402 selects the hopping node 401 as the connection destination using the scan result. For example, the edge node 402 selects the SSID "Milli-Wave-BSS3" (hopping node 401-3) with the largest value of received signal strength from the scan result shown in FIG. 14(d).

In step S1806, the edge node 402 connects to the hopping node 401-3 forming a subnetwork using the selected SSID "Milli-Wave-BSS3" by millimeter wave wireless communication.

In step S1807, the millimeter wave wireless communication unit (AP) 702 of the hopping node 401-3 permits the connection of the edge node 402 and notifies the edge node 402 of the IP address.

In step S1808, the edge node 402 transmits a registration request including the IP address notified from the hopping node 401-3 to the hopping node 401-3 by millimeter wave wireless communication.

In step S1809, the information transfer unit 716 of the hopping node 401-3 transfers the registration request received from the edge node 402 to the communication management device 403 via wireless LAN communication.

In step S1810, the communication management device 403 registers the edge node 402 with the communication system 400 upon receiving the registration request from the edge node 402 via the hopping node 401-3.

In this way, the edge node 402 can autonomously change the hopping node 401 to which it is connected, even if there is no instruction to change the connection destination from the communication management device 403 or the hopping node 401-1. .

18, for example, if the number of edge nodes 402 is uneven as in the network configuration shown in FIG. 4, the connection destination changing process described in the first embodiment is executed. be.

Therefore, the edge node 402 may lower the connection priority of the hopping node 401 when receiving the connection destination change instruction shown in step S1513 of FIG. 15 from the hopping node 401, for example. As a result, for example, when the edge node 402 selects the connection destination hopping node 401 in step 1805 of FIG. .

400 communication system 401 hopping node (relay terminal)
402 edge node (connection terminal)
403 communication management device (communication management terminal, terminal management device)
601 CPU (control unit)
701 wireless LAN communication unit (third communication unit)
702 millimeter wave wireless communication unit (AP) (first communication unit)
703 millimeter wave wireless communication unit (STA) (second communication unit)
711 communication link state measuring unit (measuring unit)
715 Edge node management unit (connection terminal management unit)
902 information acquisition unit 905 hopping node management unit (relay terminal management unit)
908 Priority determination unit

JP 2016-009977 A

Claims (9)

A communication system including a plurality of relay terminals, a plurality of connection terminals, and a communication management device ,
The relay terminal is
a first communication unit that functions as an access point for the first wireless communication and forms a subnetwork for the first wireless communication;
a second communication unit that functions as a station for the first wireless communication and connects to the subnetwork formed by other relay terminals;
a third communication unit that performs second wireless communication with the communication management device;
One of the first communication unit and the second communication unit based on the instruction regarding the communication path of the first wireless communication, which is notified from the communication management device in the second wireless communication a data transfer unit that transfers data received by the communication unit to another relay terminal or the connection terminal by the other communication unit;
a connection terminal management unit that manages the connection terminal connected to the subnetwork formed by the first communication unit;
has
The connection terminal is
Having a fourth communication unit that functions as a station for the first wireless communication and connects to the subnetwork,
The communication management device
a fifth communication unit that performs the second wireless communication with the relay terminal;
an information acquisition unit that acquires , from the plurality of relay terminals, the number of the connected terminals connected to each relay terminal using the second wireless communication ;
When the difference between the maximum number and the minimum number of connected terminals acquired by the information acquisition unit is equal to or greater than a threshold, the relay terminal having the largest number of connected terminals is selected using the second wireless communication. a relay terminal management unit that transmits control information instructing execution of processing for reducing the number of connection terminals connected to the relay terminal;
A communication system having The connection terminal management unit of the relay terminal instructs one or more connection terminals connected to the relay terminal to change connection destinations to other relay terminals in response to the reception of the control information. 2. The communication system of claim 1 , transmitting instructional information. The relay terminal has a measurement unit that measures the communication quality of the first wireless communication with the connection terminal connected to the relay terminal,
The connection terminal management unit of the relay terminal, in response to the reception of the control information, selects a connection terminal whose communication quality measured by the measurement unit is worse than that of other connection terminals among the connection terminals connected to the relay terminal. 2. The communication system according to claim 1 , wherein instruction information for instructing a change of a connection destination to another relay terminal is transmitted to the connected terminal. 4. The communication system according to claim 2, wherein said control information includes information for instructing said relay terminal having the largest number of said connected terminals to reduce the number of said connected terminals. Based on the number of connection terminals connected to each of the plurality of relay terminals, the communication management device determines that the number of connection terminals is different from the relay terminal having the largest number of connection terminals among the plurality of relay terminals. has a priority determination unit that determines the connection priority of the relay terminal of
The communication system according to any one of claims 2 to 4, wherein said control information and said instruction information include information on said connection priority determined by said priority determination unit. 6. The connection terminal according to claim 5, wherein, when receiving the instruction information from the relay terminal to which the connection terminal is connected, the connection terminal preferentially connects to the relay terminal having the higher connection priority included in the instruction information. communication system. 7. The SSID for identifying the subnetwork formed by the plurality of relay terminals includes a common character string and a character string or number different for each of the plurality of relay terminals. Communication system as described. When the first wireless communication with the relay terminal is disconnected, the connection terminal disconnects the TCP communication connection without maintaining the connection, and sends the relay terminal or another relay terminal different from the relay terminal to the connection terminal. 8. The communication system according to any one of claims 1 to 7, wherein said TCP communication is used when said first wireless communication is connected. A control method for a communication system including a plurality of relay terminals, a plurality of connection terminals, and a communication management device ,
The relay terminal
a first communication process that functions as an access point for a first wireless communication and forms a sub-network for the first wireless communication;
a second communication process that functions as a station for the first wireless communication and connects to the subnetwork formed by other relay terminals;
a third communication process for performing a second wireless communication with the communication management device;
one of the first communication process and the second communication process based on the instruction regarding the communication path of the first wireless communication, which is notified from the communication management device in the second wireless communication; Data transfer processing for transferring data received in communication processing to another relay terminal or the connection terminal in the other communication processing;
a connection terminal management process for managing the connection terminal connected to the subnetwork formed by the first communication process;
and run
The connection terminal
functioning as a station for the first wireless communication and executing a fourth communication process for connecting to the subnetwork;
The communication management device
a fifth communication process for performing the second wireless communication with the relay terminal;
an information acquisition process for acquiring , from the plurality of relay terminals, the number of the connected terminals connected to each relay terminal using the second wireless communication ;
If the difference between the maximum number and the minimum number of connected terminals acquired in the information acquisition process is equal to or greater than a threshold, the relay terminal having the largest number of connected terminals is selected using the second wireless communication. On the other hand, a relay terminal management process for transmitting control information instructing execution of a process for reducing the number of connection terminals connected to the relay terminal;
A method of controlling a communication system that performs

Images