Communication system, communication device, communication method, and computer program product

1 . A communication system comprising:

a plurality of first communication devices constituting a multihop network; and

a second communication device constituting the multihop network in collaboration with the first communication devices, the second communication device being capable of communicating with a server device via a lower-level network and via a gateway being mobile, the server device being connected to a higher-level network, wherein

the second communication device includes one or more hardware processors coupled to a memory, the one or more hardware processors being configured to:

manage schedule information containing communicable-period information indicating a communicable period during which the gateway establishes a connection with the second communication device via the lower-level network; and

transmit first communication data addressed to the server device, the first communication data being transmitted to the server device via the lower-level network and the gateway in the communicable period indicated by the communicable-period information,

each of the plurality of first communication devices is configured to store the schedule information and transmit the first communication data to the server device via the second communication device, the lower-level network, and the gateway in the communicable period indicated by the communicable-period information;

the server device is configured to store the schedule information and transmit second communication data to the second communication device via the gateway and the lower-level network in the communicable period indicated by the communicable-period information, the second communication data being addressed to one of the plurality of first communication devices; and

the gateway is configured to store the schedule information and transfer the second communication data to the second communication device via the lower-level network in the communicable period indicated by the communicable-period information.

2 . The communication system according to claim 1 , wherein the schedule information is generated and distributed in advance by the gateway or the server device.

3 . The communication system according to claim 1 , wherein the multihop network includes a plurality of the second communication devices.

4 . The communication system according to claim 3 , wherein the one or more hardware processors of each of the second communication devices are configured to:

manage the schedule information in which lower-level NW identification information and the communicable-period information are associated with one another, the lower-level NW identification information indicating the lower-level network to which the gateway is able to establish a connection, the communicable-period information indicating the communicable period during which the gateway is present within a communication range enabling communication with the second communication device via the lower-level network identified by the lower-level NW identification information; and

transmit the first communication data to the server device via the second communication device connected to the lower-level network, via the lower-level network, and via the gateway, the first communication data being transmitted in the communicable period indicated by the communicable-period information specified in the schedule information corresponding to the lower-level NW identification information of the lower-level network to which the gateway is scheduled to connect at a scheduled transmission timing.

5 . The communication system according to claim 1 , wherein

the first communication device has a function for communicating with the second communication device, and does not have a function for communicating with the lower-level network; and

the second communication device functions as a concentrator of the multihop network, and transmits the first communication data originating in the first communication device for transmission.

6 . A communication device constituting a multihop network in collaboration with a plurality of first communication devices, the communication device being capable of communicating with a server device via a lower-level network and via a gateway being mobile, the server device being connected to a higher-level network, the communication device comprising:

one or more hardware processors coupled to a memory, the one or more hardware processors being configured to:

manage schedule information containing communicable-period information indicating a communicable period during which the gateway establishes a connection with the communication device via the lower-level network; and

transmit first communication data addressed to the server device, the first communication data being transmitted to the server device via the lower-level network and the gateway in the communicable period indicated by the communicable-period information,

wherein

each of the plurality of first communication devices is configured to store the schedule information and transmit the first communication data to the server device via the communication device, the lower-level network, and the gateway in the communicable period indicated by the communicable-period information;

the server device is configured to store the schedule information and transmit second communication data to the communication device via the gateway and the lower-level network in the communicable period indicated by the communicable-period information, the second communication data being addressed to one of the plurality of first communication devices; and

the gateway is configured to store the schedule information and transfer the second communication data to the communication device via the lower-level network in the communicable period indicated by the communicable-period information.

7 . A communication method implemented by a communication device constituting a multihop network in collaboration with a plurality of first communication devices, the communication device being capable of communicating with a server device via a lower-level network and via a gateway being mobile, the server device being connected to a higher-level network, the communication method comprising:

managing schedule information containing communicable-period information indicating a communicable period during which the gateway establishes a connection with the communication device via the lower-level network; and

transmitting first communication data addressed to the server device, the first communication data being transmitted to the server device via the lower-level network and the gateway in the communicable period indicated by the communicable-period information,

wherein

each of the plurality of first communication devices is configured to store the schedule information and transmit the first communication data to the server device via the communication device, the lower-level network, and the gateway in the communicable period indicated by the communicable-period information;

the server device is configured to store the schedule information and transmit second communication data to the communication device via the gateway and the lower-level network in the communicable period indicated by the communicable-period information, the second communication data being addressed to one of the plurality of first communication devices; and

the gateway is configured to store the schedule information and transfer the second communication data to the communication device via the lower-level network in the communicable period indicated by the communicable-period information.

8 . A computer program product comprising a non-transitory computer-readable recording medium on which a computer program executable by a computer is recorded, the computer constituting a multihop network in collaboration with a plurality of first communication devices, the computer being capable of communicating with a server device via a lower-level network and via a gateway being mobile, the server device being connected to a higher-level network, the computer program instructing the computer to:

manage schedule information containing communicable-period information indicating a communicable period during which the gateway establishes a connection with the computer via the lower-level network; and

transmit first communication data addressed to the server device, the first communication data being transmitted to the server device via the lower-level network and the gateway in the communicable period indicated by the communicable-period information,

wherein

each of the plurality of first communication devices is configured to store the schedule information and transmit the first communication data to the server device via the computer, the lower-level network, and the gateway in the communicable period indicated by the communicable-period information;

the server device is configured to store the schedule information and transmit second communication data to the computer via the gateway and the lower-level network in the communicable period indicated by the communicable-period information, the second communication data being addressed to one of the plurality of first communication devices; and

the gateway is configured to store the schedule information and transfer the second communication data to the computer via the lower-level network in the communicable period indicated by the communicable-period information.