Ad hoc network route construction system, node, and center node

1. An ad hoc network route construction system, comprising:

one center node; and

a plurality of next hop nodes, wherein

the center node

generates a request packet including a data part and a header part, a MAC (Media Access Control) address of the center node and position information of the center node being described in the data part, a positive integer value being described in the header part as time to live, and

transmits the request packet to one or more next hop nodes located in an area where the one or more next hop nodes can communicate with the center node,

each of the next hop nodes

receives the request packet,

if determining that a value of the time to live described in the header part of the request packet is 0,

generates a reply packet including a data part, all of MAC addresses and all pieces of position information described in the data part of the received request packet being described in the data part of the reply packet, and

transmits the reply packet to a request source node as a source of the received request packet,

each of the next hop nodes excluding the next hop node being a source of the reply packet further

receives the reply packet from a request destination node, and

transmits the received reply packet to the request source node, and the center node further

receives one or more reply packets from one or more request destination nodes, and then

creates, at regular time intervals, a routing table based on all of MAC addresses and all pieces of position information described in data parts of the received one or more reply packets.

2. The ad hoc network route construction system according to claim 1 , wherein

each of the next hop nodes

if determining that a value of the time to live described in the header part of the request packet is 0, further

determines whether or not there is a request destination node being a destination of the request packet, and

if determining that there is the request destination node,

additionally describes a MAC address and a position information of the next hop node itself in the data part of the received request packet, and

transmits a request packet, in which the time to live of the header part of the received request packet is reset, to the request destination node.

3. The ad hoc network route construction system according to claim 1 , wherein

each of the next hop nodes

if determining that a value of the time to live described in the header part of the request packet is not 0,

determines whether or not there is a request destination node being a destination of the request packet,

if determining that there is the request destination node,

additionally describes a MAC address and position information of the next hop node itself in the data part of the received request packet, and

transmits a request packet, in which a value described in the header part of the received request packet as the time to live is decremented, to the request destination node.

4. The ad hoc network route construction system according to claim 2 , wherein

each of the next hop nodes

if determining that there is no request destination node, determines that the next hop node itself is a terminal node,

the terminal node

generates a reply packet including a data part describing all the MAC addresses and all the position information described in the data part of the received request packet, and

transmits the reply packet to a request source node being a source of the received request packet.

5. The ad hoc network route construction system according to claim 2 , wherein

each of the next hop nodes

when determining whether or not there is the request destination node,

reads position information of the request source node from the data part of the received request packet, and

determines, based on the position information of the request source node and the position information of the next hop node itself, whether or not there is the request destination node located at a position away from a position of the request source node.

6. The ad hoc network route construction system according to claim 5 , wherein

each of the next hop nodes

when determining whether or not there is the request destination node,

divides an area, in which the next hop node itself can perform communication, into two communicable areas by a straight line that is orthogonal to a line segment and passes through the position of the next hop node itself, the line segment connecting the position of the request source node and the position of the next hop node itself, and

determines whether or not there is the request destination node located in the area including no position of the request source node out of the two communicable areas.

7. The ad hoc network route construction system according to claim 6 , wherein

each of the next hop nodes

if receiving request packets from a plurality of request source nodes,

additionally describes the MAC address of the next hop node itself and the position information of the next hop node itself in the data part of one of the received request packets, and

transmits the described request packet to the request destination node.

8. The ad hoc network route construction system according to claim 7 , wherein

each of the next hop nodes

when determine whether or not there is the request destination node,

transmits a HELLO packet to one or more different next hop nodes located in an area, in which the one or more different next hop nodes can communicate with the next hop node itself,

requests, from the one or more different next hop nodes, a response packet in which position information of the one or more different next hop nodes as response sources is additionally described, as a response packet to the HELLO packet,

receives, from the one or more different next hop nodes, the response packet in which the position information of the one or more different next hop nodes is additionally described, and

determines whether or not there is the request destination node based on the position information of the one or more different next hop nodes additionally described in the received packet.

9. A node, included in an ad hoc network route construction system including one center node, and a plurality of nodes, the node comprising:

a packet control unit that

receives, from the center node, a request packet including a data part and a header part, a MAC (Media Access Control) address of the center node and position information of the center node being described in the data part, a positive integer value being described in the header part as time to live;

if determining that a value of the time to live described in the header part of the request packet is 0,

generates a reply packet including a data part, all of MAC addresses and all pieces of position information described in the data part of the received request packet being described in the data part of the reply packet; and

transmits the reply packet to a request source node as a source of the received request packet.

10. The node according to claim 9 , wherein

the packet control unit

if determining that a value of the time to live described in the header part of the request packet is 0, further

determines whether or not there is a request destination node being a destination of the request packet, and

if determining that there is the request destination node,

additionally describes a MAC address and a position information of the node itself in the data part of the received request packet, and

transmits a request packet, in which the time to live of the header part of the received request packet is reset, to the request destination node.

11. The node according to claim 9 , wherein

the packet control unit

if determining that a value of the time to live described in the header part of the request packet is not 0,

determines whether or not there is a request destination node being a destination of the request packet,

if determining that there is the request destination node,

additionally describes a MAC address and position information of the next hop node itself in the data part of the received request packet, and

transmits a request packet, in which a value described in the header part of the received request packet as the time to live is decremented, to the request destination node.

12. The node according to claim 10 , wherein

the packet control unit

if determining that there is no request destination node, determines that the next hop node itself is a terminal node,

if determining that the next hop node itself is the terminal node

generates a reply packet including a data part describing all the MAC addresses and all the position information described in the data part of the received request packet, and

transmits the reply packet to a request source node being a source of the received request packet.

13. A center node, included in an ad hoc network route construction system including

one center node, and

a plurality of next hop nodes, wherein

the center node

generates a request packet including a data part and a header part, a MAC (Media Access Control) address of the center node and position information of the center node being described in the data part, a positive integer value being described in the header part as time to live, and

transmits the request packet to one or more next hop nodes located in an area where the one or more next hop nodes can communicate with the center node,

each of the next hop nodes

receives the request packet,

if determining that a value of the time to live described in the header part of the request packet is 0,

generates a reply packet including a data part, all of MAC addresses and all pieces of position information described in the data part of the received request packet being described in the data part of the reply packet, and

transmits the reply packet to a request source node as a source of the received request packet,

each of the next hop nodes excluding the next hop node being a source of the reply packet further

receives the reply packet from a request destination node, and

transmits the received reply packet to the request source node, and the center node further

receives one or more reply packets from one or more request destination nodes, and then

creates, at regular time intervals, a routing table based on all of MAC addresses and all pieces of position information described in data parts of the received one or more reply packets.