First node, network system, method and program

Abstract

To provide a first node, a network system, a method and a program which can quickly change the ad hoc network topology of mobile communication.SOLUTION: A first node 11 includes: a transmitter unit 111 which sends data to a second node 12 in a network in order to send data from the first node 11 to a third node 13 via the second node 12; a receiver unit 112 which, based on a distance between the second node 12 and the third node 13 and transmission power of the second node 12, receives communication impossible information from a fourth node 14 which has predicted that communication between the second node 12 and the third node 13 would be impossible; and a control unit 113 which, when receiving the communication impossible information, selects a fifth node 15 in place of the second node 12 among the plurality of nodes, based on each distance among a plurality of nodes in the network and the transmission power of each of the plurality of nodes.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a first node, a network system, a method, and a program, and more particularly to a first node, a network system, a method, and a program that are capable of quickly changing an ad-hoc network topology for mobile communications. [Background technology]

[0002] In many communication methods used in ad-hoc networks, whether communication is possible over the communication links between all nodes in the network is determined by Hello messages or the like periodically sent by each node, and then the network configuration (network topology) is determined. Changes to the network configuration are made by detecting changes in the communication state of the links between nodes using Hello messages or the like, and then exchanging control messages for controlling the network topology, the control messages including information about the links between the nodes. Note that communication links are sometimes simply referred to as links.

[0003] Paragraph 0019-0022 of Patent Document 1 states, "When the station starts up, it acquires its own station's location information by a location information acquisition means. Next, it broadcasts its own station name identification information, location information, and the station name identification information and location information of communicable subscriber stations. Subscriber stations B12 and C13 that receive this broadcast transmission respond by similarly transmitting their own station name identification information, location information, and the station name identification information and location information of communicable subscriber stations. However, subscriber station D14 does not respond because it is outside the radio wave coverage of subscriber station A11. Subscriber station A11 edits the subscriber station layout table in its own station based on the received content." It is described in paragraphs 0029-0032 of Patent Document 1 that "When the broadcast transmission from the subscriber station C13 is no longer received in the operation step ST4, the subscriber station layout table is updated in the operation step ST4 based on the position information of the subscriber station C13 contained in the broadcast transmission from the subscriber station B12 that can continue to be received. The position information of the subscriber station C13 is relayed and updated by the subscriber station B12, and the communication path information is also updated to the content of only the relay path as direct communication becomes impossible. When transmission data addressed to the subscriber station C13 occurs, the communication path via the subscriber station B12 is selected in the subsequent operation step ST6." However, when it is predicted that communication between each node in the network will be impossible, it is not described that a node that can communicate is selected based on the distance between the multiple nodes in the network and the transmission power of each of the multiple nodes, and data is transmitted to the destination node via the node that can communicate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-229173 A Summary of the Invention [Problem to be solved by the invention]

[0005] As mentioned above, in networks, changes in the communication status of links are detected by regular transmission of Hello messages from each node. Therefore, when a communication disconnection occurs in a link, it takes time to detect it, which causes the network topology to take time to change, which is an issue. In particular, in the case of a moving object moving at high speed such as an airplane, the relative positions of the nodes change significantly, so the communication disconnection of the links between the nodes can last for a long period of time, making the network susceptible to the effects of such disruptions.

[0006] An object of the present disclosure is to provide a first node, a network system, a method, and a program that solves any of the above-mentioned problems. [Means for solving the problem]

[0007] The first node according to the present disclosure comprises: A transmitter for transmitting data from the node to a third node via a second node in a network, the data being transmitted to the second node; a receiving unit that receives information of communication failure from a fourth node that predicts communication failure between the second node and the third node based on a distance between the second node and the third node and a transmission power of the second node; a control unit that, when receiving the information indicating that communication is not possible, selects a fifth node from among the plurality of nodes to replace the second node based on distances between the plurality of nodes in the network and the transmission power of each of the plurality of nodes, and controls the node to transmit the data to the third node via the fifth node; Equipped with.

[0008] The first node according to the present disclosure comprises: A transmitter for transmitting data from the node to a third node via a second node in a network, the data being transmitted to the second node; a receiving unit that receives information of communication impossibility from a fourth node that predicts communication impossibility between the second node and the third node based on a position of the second node, a position of the third node, and a transmission range when the second node transmits the data; a control unit that, when receiving the information indicating that communication is not possible, selects a fifth node from among the plurality of nodes to replace the second node based on positions between the plurality of nodes in the network and the transmission ranges of each of the plurality of nodes, and controls the node to transmit the data to the third node via the fifth node; Equipped with.

[0009] The network system according to the present disclosure includes: A first node, a second node, a third node, a fourth node, and a fifth node, The first node, a first transmitting unit configured to transmit data from the first node to the third node via the second node in a network; a first receiving unit that receives information of communication failure from a fourth node that predicts communication failure between the second node and the third node based on a distance between the second node and the third node and a transmission power of the second node; a control unit that, when receiving the information indicating that communication is not possible, selects a fifth node from among the plurality of nodes to replace the second node based on distances between the plurality of nodes in the network and the transmission power of each of the plurality of nodes, and controls the node to transmit the data to the third node via the fifth node; The second node, A second receiving unit that receives the data from the first node; a second transmission unit that transmits the data to the third node; the second receiving unit does not receive the data from the first node when the communication failure is predicted, the second transmission unit, when the communication failure is predicted, does not transmit the data to the third node; The third node, a third receiving unit that receives the data from the second node; the third receiving unit receives the data from the fifth node when the communication failure is predicted, The fourth node, A prediction unit that predicts the communication failure based on a distance between the second node and the third node and the transmission power of the second node; a fourth transmission unit that transmits the communication impossible information to the first node, The fifth node, a fifth receiving unit that receives the data from the first node when the communication failure is predicted; and a fifth transmission unit that transmits the data to the third node when the communication failure is predicted. Network system.

[0010] The method according to the present disclosure comprises: transmitting data from a first node to a second node in a network for transmission of said data to a third node via said second node; receiving information of communication failure from a fourth node that predicts communication failure between the second node and the third node based on a distance between the second node and the third node and a transmission power of the second node; When the information indicating that communication is not possible is received, a fifth node is selected from among the plurality of nodes to replace the second node, based on distances between the plurality of nodes in the network and the transmission power of each of the plurality of nodes, and the data is transmitted from the node to the third node via the fifth node; Equipped with.

[0011] The program according to the present disclosure is transmitting data from a first node to a second node in a network for transmission of said data to a third node via said second node; receiving information of communication failure from a fourth node that predicts communication failure between the second node and the third node based on a distance between the second node and the third node and a transmission power of the second node; When the information indicating that communication is not possible is received, a fifth node is selected from among the plurality of nodes to replace the second node, based on distances between the plurality of nodes in the network and the transmission power of each of the plurality of nodes, and the data is transmitted from the node to the third node via the fifth node; to be executed by the computer. Effect of the Invention

[0012] According to the present disclosure, it is possible to provide a first node, a network system, a method, and a program capable of quickly changing an ad-hoc network topology for mobile communications. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a block diagram illustrating a first node according to the first embodiment. [Diagram 2] 1 is a block diagram illustrating a network system according to a first embodiment. [Diagram 3] 2 is a block diagram illustrating a node according to the first embodiment. FIG. [Figure 4] 1 is a block diagram illustrating a network system according to a first embodiment. [Diagram 5] FIG. 2 is a diagram illustrating an example of routing information of each node according to the first embodiment. [Figure 6] 1 is a block diagram illustrating a network system according to a first embodiment. [Figure 7] FIG. 2 is a diagram illustrating an example of routing information of each node according to the first embodiment. [Figure 8] 1 is a block diagram illustrating a network system according to a first embodiment. [Figure 9]FIG. 2 is a diagram illustrating an example of routing information of each node according to the first embodiment. [Figure 10] FIG. 11 is a block diagram illustrating a first node according to a second embodiment. [Figure 11] FIG. 11 is a block diagram illustrating a network system according to a second embodiment. [Figure 12] FIG. 11 is a diagram illustrating an example of routing information of each node according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same or corresponding elements are given the same reference numerals, and for clarity of explanation, duplicate explanations will be omitted as necessary.

[0015] [Embodiment 1] <Overview of the first node configuration> FIG. 2 is a block diagram illustrating a first node according to the first embodiment. FIG. 1 shows a minimum configuration of a first node according to the first embodiment.

[0016] As shown in Fig. 1, the first node 11 according to the first embodiment includes a transmitting unit 111, a receiving unit 112, and a control unit 113. Each node may be referred to as a mobile object or a communication device. Communication between nodes may be referred to as mobile communication.

[0017] The transmitter 111 transmits data to the second node 12 in order to transmit data from the first node 11 to the third node 13 via the second node 12 within the network. In the network according to the first embodiment, the nodes communicate directly with each other, so the network is sometimes called an ad-hoc network. The connection form of the ad-hoc network is called an ad-hoc network topology.

[0018] The receiver 112 receives information of communication impossibility from the fourth node 14 that predicts communication impossibility between the second node 12 and the third node 13 based on the distance between the second node 12 and the third node 13 and the transmission power of the second node 12. When the receiver 112 cannot receive the communication impossibility information directly from the fourth node 14, it receives the communication impossibility information via another node (the second node 12 or a fifth node 15 described later).

[0019] When the control unit 113 receives information indicating that communication is not possible from the fourth node 14, it selects the fifth node 15 to replace the second node 12 from among the multiple nodes based on the distances between the multiple nodes in the network and the transmission power of each of the multiple nodes. The control unit 113 controls the transmission of data from the first node 11 to the third node 13 via the fifth node 15.

[0020] When the control unit 113 receives information indicating that communication is not possible from the fourth node 14, it selects the fifth node 15 based on the mutual distances between the first node 11, the second node 12, the third node 13, the fourth node 14, and the fifth node 15, and the respective transmission powers of the first node 11, the second node 12, the third node 13, the fourth node 14, and the fifth node 15.

[0021] The control unit 113 determines the transmission power of the first node 11 based on the location information of the first node 11 and the location information of the second node 12 .

[0022] The receiver 112 may receive information of communication impossibility from the fourth node 14 that predicts communication impossibility between the second node 12 and the third node 13 based on the position of the second node 12, the position of the third node 13, and the transmission range when transmitting data of the second node 12. When the controller 113 receives the information of communication impossibility from the fourth node 14, the controller 113 may select a fifth node 15 to replace the second node 12 from among the multiple nodes based on the positions between the multiple nodes in the network and the transmission ranges of each of the multiple nodes.

[0023] The transmitter 111 transmits a message including information that the next hop node is the second node 12, that the destination node that is the destination of the communication is the third node 13, and information on the transmission power of the first node 11. Furthermore, when the receiver 112 receives information that communication is not possible, the transmitter 111 transmits a message including information that the next hop node is the fifth node 15, that the destination node that is the destination of the communication is the third node 13, and information on the transmission power of the first node 11. The second node 12 and the fourth node 14 receive the message.

[0024] By receiving the message, the second node 12 knows that it (the second node 12) is the next hop node and that the destination of the communication is the third node 13. The second node 12 transmits a message including the next hop node and the destination node being the third node 13. The fourth node 14 receives the message addressed to the third node 13 transmitted from the second node 12 if it is within a receivable range. Upon receiving the message, the fourth node 14 predicts that communication between the second node 12 and the third node 13 will be impossible.

[0025] This allows the communication of a link that is not available for communication to be changed to another link in the ad hoc network, thereby shortening the time during which communication is not available between nodes. As a result, according to the first embodiment, it is possible to provide a first node, a network system, a method, and a program that are capable of quickly changing the ad hoc network topology for mobile communication.

[0026] Furthermore, in the first embodiment, communication failure is predicted rather than actually measured and detected, so that the ad-hoc network topology can be changed more quickly compared to a case where communication failure is detected.

[0027] <Outline of network system configuration> FIG. 2 is a block diagram illustrating a network system according to the first embodiment. FIG. 2 shows a minimum configuration of the network system according to the first embodiment.

[0028] As shown in Fig. 2, the network system 10s according to the first embodiment includes a first node 11, a second node 12, a third node 13, a fourth node 14, and a fifth node 15. The first node 11 has already been described, so a description thereof will be omitted. In the first node, the transmitting unit is referred to as a first transmitting unit, and the receiving unit is referred to as a first receiving unit. The fourth node 14 is assumed to be capable of communicating with the second node 12 and the fifth node 15.

[0029] The second node 12 has a second receiving unit 122 and a second transmitting unit 121. The second receiving unit 122 receives data from the first node 11. The second transmitting unit 121 transmits data to the third node 13. When it is predicted that communication between the second node 12 and the third node 13 will be impossible, the second receiving unit 122 does not receive data from the first node 11. When it is predicted that communication between the second node 12 and the third node 13 will be impossible, the second transmitting unit 121 does not transmit data to the third node.

[0030] The third node 13 has a third receiving unit 132. The third receiving unit 132 receives data from the second node 12. The third receiving unit 132 receives data from the fifth node 15 when communication failure between the second node 12 and the third node 13 is predicted.

[0031] The fourth node has a prediction unit 143 and a fourth transmission unit 141. The prediction unit 143 predicts that communication between the second node 12 and the third node 13 will be impossible based on the distance between the second node 12 and the third node 13 and the transmission power of the second node 12. The fourth transmission unit 141 transmits information that communication between the second node 12 and the third node 13 will be impossible to the first node 11.

[0032] The fourth node 14 receives the location information and the transmission power of multiple nodes in the network. The fourth node 14 calculates the distance between the second node 12 and the third node 13 based on the location information of the second node 12 and the location information of the third node 13.

[0033] The fifth node has a fifth receiving unit 152 and a fifth transmitting unit 151. The fifth receiving unit 152 receives data from the first node 11 when it is predicted that communication between the second node 12 and the third node 13 will be impossible. The fifth transmitting unit 151 transmits data to the third node 13 when it is predicted that communication between the second node 12 and the third node 13 will be impossible.

[0034] <Node configuration details> FIG. 3 is a block diagram illustrating a node according to the first embodiment. Each of the first node 11 to the fifth node 15 shown in FIG. 1 has the same configuration, and the node 10 shown in FIG. 3 is shown as a representative of the nodes having the same configuration.

[0035] As shown in FIG. 3, node 10 is a mobile body having communication capabilities, and includes a transmitting unit 101, a receiving unit 102, a routing control unit 103, a routing information storage unit 104, a wireless communication monitoring unit 105, a message processing unit 106, a communication-prohibited link information storage unit 107, a surrounding node position information storage unit 108, a local node position information storage unit 109, a routing change notification unit 110, and a message creation unit 111m.

[0036] The transmitting unit 101 shown in Fig. 3 corresponds to the transmitting unit 111 shown in Fig. 1, and the receiving unit 102 shown in Fig. 3 corresponds to the receiving unit 112 shown in Fig. 1. Also, the routing control unit 103, the routing information storage unit 104, the wireless communication monitoring unit 105, the message processing unit 106, the communication-prohibited link information storage unit 107, the peripheral node position information storage unit 108, the own node position information storage unit 109, the routing change notification unit 110, and the message creation unit 111m shown in Fig. 3 correspond to the control unit 113 shown in Fig. 1. Note that the elements shown in Fig. 3 and the elements shown in Fig. 1 do not necessarily have to have the correspondence relationship shown above.

[0037] Based on the routing information stored in the routing information storage unit 104, the transmitter 101 includes information such as the next hop node, destination node, transmission power (transmission output of wireless communication), and wireless transmission range in a message, converts the message into a wireless signal, and transmits the message to other nodes.

[0038] The receiving unit 102 receives a radio signal from another node, and generates (constructs) a message from the received radio signal.

[0039] The routing control unit 103 also refers to the information stored in the peripheral node position information storage unit 108, and determines the routing that indicates the communication path within the network. The routing control unit 103 exchanges information required for exchanging routing information (referred to as routing information) with other nodes via the transmitting unit 101 and the receiving unit 102. In this way, the routing control unit 103 exchanges routing information with other nodes. The routing control unit 103 stores the determined routing information in the routing information storage unit 104.

[0040] The routing information storage unit 104 stores the routing information. The routing information storage unit 104 updates the routing information based on the routing information notified from the routing control unit 103.

[0041] The wireless communication monitoring unit 105 receives wireless signals other than those addressed to the node 10 itself via the receiving unit 102, and judges whether or not there is a link with which communication is not possible (a communication-prohibited link) based on information acquired from the routing information storage unit 104, the peripheral node position information storage unit 108, and the node itself position information storage unit 109. The information acquired by the wireless communication monitoring unit 105 includes the position information of each node, the transmission power of each node, and the like.

[0042] The wireless communication monitoring unit 105 predicts and detects communication-disabled links based on the position information of each node and information such as the transmission power (transmission output) of each node. When the wireless communication monitoring unit 105 detects a new communication-disabled link, it notifies the communication-disabled link information storage unit 107 and the routing change notification unit 110 of the detected communication-disabled link information.

[0043] The message processing unit 106 processes a message received via the receiving unit 102 and addressed to the node 10 itself.

[0044] The communication-disabled link information storage unit 107 stores information on communication-disabled links. The communication-disabled link information storage unit 107 updates the routing information with the information on communication-disabled links notified by the wireless communication monitoring unit 105.

[0045] The surrounding node position information storage unit 108 stores position information (latitude, longitude, altitude, direction of movement, etc.) of nodes present in the vicinity of the node 10, information on the node's speed, and information on the node's acceleration, based on information notified by radar or other nodes.

[0046] The local node position information storage unit 109 stores the position information of the local node 10 obtained from a GPS (Global Positioning System), a navigation system, or the like.

[0047] Based on the information on the link that cannot be communicated with, notified by the wireless communication monitoring unit 105, the routing change notification unit 110 creates a message to notify other nodes that the link is an uncommunicable (unusable) link, and notifies the transmitting unit 101.

[0048] The message creation unit 111m creates a message to be transmitted to other nodes, and notifies the transmission unit 101 of the created message.

[0049] <Network system operation> FIG. 4 is a block diagram illustrating a network system according to the first embodiment. FIG. 4 shows a state when communication from the first node 11 to the third node 13 is possible. The solid lines in FIG. 4 indicate the communication paths from the first node 11 to the third node 13 at a certain time, and the dotted lines indicate links with a high probability of communication.

[0050] FIG. 5 is a diagram illustrating routing information of each node according to the first embodiment. FIG. 6 is a block diagram illustrating a network system according to the first embodiment. FIG. 6 shows a state after some time has passed since FIG. 4, and shows a state in which communication from the second node 12 to the third node 13 is not possible.

[0051] FIG. 7 is a diagram illustrating the routing information of each node according to the first embodiment. FIG. 8 is a block diagram illustrating a network system according to the first embodiment. FIG. 9 is a diagram illustrating routing information of each node according to the first embodiment.

[0052] In the initial state, an ad-hoc network as shown in Fig. 4 is configured by an existing ad-hoc routing technology. The communication path from the first node 11 to the third node 13 is the path shown by the solid line in Fig. 4 (first node 11 → second node 12 → third node 13).

[0053] 5, when the ad-hoc network shown in FIG. 4 is configured, the routing information of the first node 11 has the destination node as the third node 13 and the next hop node as the second node 12. Also, the routing information of the second node 12 has the destination node as the third node 13 and the next hop node as the third node 13.

[0054] Next, assume that time has passed from the initial state and the communication environment has become as shown in Fig. 6. In Fig. 6, it is assumed that the relative positions of the nodes have changed, or the radio wave environment of the communication path from the second node 12 to the third node 13 has deteriorated, so that communication (wireless communication) from the second node 12 to the third node 13 has become impossible. However, it is assumed that communication from the first node 11 to the second node 12 does not become impossible.

[0055] As shown in FIG. 7, when the ad-hoc network shown in FIG. 6 is configured, the routing information of the first node 11 has the destination node as the third node 13 and the next hop node as the second node 12. Moreover, the routing information of the second node 12 has the destination node as the third node 13 and the next hop node as the third node 13. Moreover, the routing information of the fourth node 14 has the destination node as the second node 12 and the next hop node as the second node 12. Moreover, the other destination node is the fifth node 15 and the other next hop node is the fifth node 15.

[0056] 6, a message is transmitted from the first node 11 to the third node 13. At this time, the message creation unit 111m of the first node 11 creates a message to be transmitted to the third node 13, and notifies the created message to the transmission unit 101 of the first node 11. The transmission unit 101 of the first node 11 confirms the destination of the message (the third node 13 in this example) from the notified message, and queries the routing information storage unit 104 about the next hop node when transmitting the message to this destination. From this query, the transmission unit 101 of the first node 11 confirms that the next hop node is the second node 12, and transmits the message to the second node 12 by wireless communication.

[0057] The receiving unit 102 of the second node 12 receives the wireless communication transmitted from the first node 11 and generates (constructs) a message. Since the generated message is not addressed to its own node (the second node 12 in this case), the transmitting unit 101 is notified of the message. The transmitting unit 101 of the second node 12 queries the routing information storage unit 104, confirms that the next hop node is the third node 13, and transmits the message to the third node 13 via wireless communication.

[0058] At this time, since the third node 13 is not present within the communication range of the second node 12, the third node 13 cannot receive the message transmitted from the second node 12.

[0059] On the other hand, since the fourth node 14 exists within the communication range of the second node 12, the fourth node 14 can receive the message transmitted from the second node 12. The fourth node 14 receives the message transmitted from the second node 12. That is, the receiving unit 102 of the fourth node 14 receives the wireless communication and generates a message. Since the destination and next hop node of the message are the third node 13 and not the own node (the fourth node 14 in this case), the wireless communication monitoring unit 105 is notified of the message.

[0060] The wireless communication monitoring unit 105 of the fourth node 14 inquires of the communication-disabled link information storage unit 107 whether or not link information between the second node 12 and the third node 13 is stored, and confirms that it is not stored. The wireless communication monitoring unit 105 of the fourth node 14 acquires the position information of the second node 12 and the third node 13 from the surrounding node position information storage unit 108, and acquires the position information of its own node from its own node position information storage unit 109.

[0061] The wireless communication monitoring unit 105 of the fourth node 14 predicts that wireless communication from the second node 12 to the third node 13 will be impossible, based on the position information of each node and information such as the transmission power (transmission output) of each node contained in the message.

[0062] When the wireless communication monitoring unit 105 of the fourth node 14 predicts that communication is impossible, it notifies the communication impossible link information storage unit 107 and the routing change notification unit 110 of information on the communication impossible link.

[0063] The communication-impossible link information storage unit 107 of the fourth node 14 stores information on the communication-impossible links. The routing change notification unit 110 of the fourth node 14 creates a message indicating that the communication link between the second node 12 and the third node 13 is not capable of communication and requests a change in routing within the network, based on the notified information on the communication-impossible links. The routing change notification unit 110 of the fourth node 14 notifies the sending unit 101 of the created message in order to transmit the message to the network (ad-hoc network) to which the node belongs.

[0064] The transmitting unit 101 of the fourth node 14 inquires of the routing information storage unit 104 about nodes with which direct communication is possible, and transmits a message to the obtained directly communicable nodes, such as the second node 12 and the fifth node 15.

[0065] The second node 12 and the fifth node 15 receive the message and change the routing (communication path) in the ad-hoc network according to the routing protocol used in the ad-hoc network. The second node 12 or the fifth node 15 notifies the first node 11 of the change in routing.

[0066] As a result, the communication path from the first node 11 to the third node 13 is changed to, for example, the routing as shown in Fig. 8. After the network configuration is changed, that is, after the routing (communication path) is changed, communication from the first node 11 to the third node 13 becomes possible via the communication path shown in Fig. 8.

[0067] The features of the first embodiment are as follows. A node (communication device) mounted on a mobile object participating in an ad-hoc network, A function of acquiring location information of the own node and surrounding nodes around the own node; A node characterized by being able to change the network topology of the ad hoc network by identifying links through which communication is not possible from the location information when receiving a message and notifying other nodes of the links through which communication is not possible.

[0068] [Embodiment 2] FIG. 10 is a block diagram illustrating a first node according to the second embodiment. FIG. 11 is a block diagram illustrating a network system according to the second embodiment. FIG. 12 is a diagram illustrating the routing information of each node according to the second embodiment.

[0069] The node 20 according to the second embodiment differs from the node 10 according to the first embodiment in that a network design storage unit is added.

[0070] 10, the network design storage unit 111n stores the transmission time, the transmitting node (next hop node), the receiving node, the destination node, the transmission power, etc. of each node participating in the ad hoc network. The network design storage unit 111n notifies the wireless communication monitoring unit 105 of necessary information in response to an inquiry.

[0071] In embodiment 1, upon receiving a message from the second node 12 to the third node 13, the wireless communication monitoring unit 105 of the fourth node 14 predicted whether communication was not possible over the link between the second node 12 and the third node 13.

[0072] In contrast, in the second embodiment, it is confirmed that the own node (in this case, the fourth node 14) is present between the second node 12 and the third node 13, and if the wireless communication monitoring unit 105 of the fourth node 14 fails to receive the message addressed to the third node 13 from the second node 12 at the time of sending the message, it also predicts a link that cannot be communicated with.

[0073] The operation of the second embodiment will be described. The operations up to the point where the second node 12 performs wireless communication toward the third node 13 are the same as those in the embodiment 1. The operations thereafter are as follows.

[0074] As shown in FIG. 11, the third node 13 and the fourth node 14 are not within the communication range of the second node 12, so the third node 13 and the fourth node 14 do not receive the message.

[0075] 12, in this case, the routing information of the first node 11 has the destination node as the third node 13 and the next hop node as the second node 12. In addition, the routing information of the second node 12 has the destination node as the third node 13 and the next hop node as the third node 13. In addition, the routing information of the fourth node 14 has the destination node as the fifth node 15 and the next hop node as the fifth node 15.

[0076] The wireless communication monitoring unit 105 of the fourth node 14 periodically queries the network design storage unit 111n to confirm whether its own node (the fourth node 14 in this case) is between the transmitting node and the destination node at the time of transmission by the other node. Whether or not the own node is between them is confirmed by acquiring the position of the transmitting node from the surrounding node position information storage unit 108 and acquiring the position information of the own node from the own node position information storage unit 109 to confirm the relative position. If it is confirmed that the own node (the fourth node 14 in this case) is between the second node 12 and the third node 13 and has not received the corresponding message at that time, the following steps are executed.

[0077] Step S101: The wireless communication monitoring unit 105 of the fourth node 14 inquires of the communication-prohibited link information storage unit 107 whether link information between the second node 12 and the third node 13 is stored, and confirms that the link information is not stored.

[0078] Step S102: The wireless communication monitoring unit 105 of the fourth node 14 predicts that communication from the second node 12 to the third node 13 is not possible, based on the position information of each node and information such as transmission output included in the message.

[0079] Step S103: If the wireless communication monitoring unit 105 of the fourth node 14 predicts that communication is impossible, it notifies the communication impossible link information storage unit 107 and the routing change notifying unit 110 of information on the communication impossible link.

[0080] Step S104: The communication impossible link information storage unit 107 of the fourth node 14 stores this communication impossible link information.

[0081] Step S105: Based on the notified link information, the routing change notification unit 110 of the fourth node 14 creates a message for the ad hoc network to which it belongs, informing the transmitter 101 of the fourth node 14 that the link between the second node 12 and the third node 13 is not communicable and requesting a change in routing within the ad hoc network, and notifies the transmitter 101 of the fourth node 14.

[0082] Step S106: The transmitting unit 101 of the fourth node 14 inquires of the routing information storage unit 104 about nodes with which direct communication is possible, and transmits a message to the acquired directly communicable nodes such as the fifth node 15.

[0083] Step S107: The fifth node 15 receives the message transmitted from the fourth node 14, and changes the communication path in the ad-hoc network in accordance with the routing protocol used in the ad-hoc network.

[0084] As a result, the communication path is changed to one from the first node 11 to the third node 13 as shown in FIG. 8, and communication from the first node 11 to the third node 13 via the fifth node 15 becomes possible.

[0085] In the above embodiment, the present invention has been described as being configured as hardware, but the present invention is not limited to this. The present invention can also be realized by having a CPU (Central Processing Unit) execute a computer program to process each component.

[0086] In the above embodiment, the program can be stored and supplied to the computer using various types of non-transitory computer readable media. The non-transitory computer readable media includes various types of tangible storage media. Examples of the non-transitory computer readable media include magnetic recording media (specifically, flexible disks, magnetic tapes, and hard disk drives), magneto-optical recording media (specifically, magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, semiconductor memories (specifically, mask ROMs, PROMs (Programmable ROMs), and EPROMs (Erasable PROMs)), flash ROMs, and RAMs (Random Access Memory). The program may also be supplied to the computer by various types of transitory computer readable media. Examples of the transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The transitory computer readable media can supply the program to the computer via wired communication paths such as electric wires and optical fibers, or wireless communication paths.

[0087] Additionally, although operations are depicted in a particular order, this should not be understood as requiring such operations to be performed in the particular order or sequential order depicted, or that all of the depicted operations be performed, to achieve desirable results. In certain situations, multitasking and parallel processing may be advantageous. Similarly, although details of several specific embodiments are included in the above discussion, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable combination.

[0088] Although the present invention has been described above with reference to the embodiment, the present invention is not limited to the above. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the invention.

[0089] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0090] 10s: Network Systems 10: Node 101: Transmitter 102: Receiving unit 103: Routing control unit 104: Routing information storage unit 105: Radio communication monitoring unit 106: Message processing unit 107: Communication failure link information storage unit 108: Peripheral node location information storage unit 109: Local node location information storage unit 110: Routing change notification section 111m: Message Creation Section 11: First node 111: Transmitter 112: Receiving unit 113: Control unit 12: Second node 121: Second transmission unit 122: Second receiving unit 13: Third node 132: Third receiving unit 14: 4th node 141: 4th transmission unit 143: Prediction Department 15: 5th node 151: 5th transmission unit 152: 5th receiving unit

Claims

1. A transmitter for transmitting data from the node to a third node via the second node in a network, the data being transmitted to the second node; a receiving unit that receives information of a predicted communication failure from a fourth node that predicts a communication failure between the second node and the third node based on a distance between the second node and the third node and a transmission power of the second node; a control unit that, when receiving the predicted communication unavailability information, selects a fifth node from among the plurality of nodes to replace the second node based on distances between the plurality of nodes in the network and the transmission power of each of the plurality of nodes, and controls the node to transmit the data to the third node via the fifth node; A first node comprising:

2. when the control unit receives the predicted information of communication unavailability, the control unit selects the fifth node based on distances between the first node, the second node, the third node, the fourth node, and the fifth node, and the transmission powers of the first node, the second node, the third node, the fourth node, and the fifth node. The first node according to claim 1 .

3. the transmission unit transmits a message including information indicating that a next hop node is the second node, information indicating that a destination node that is a destination of communication is the third node, and information on the transmission power of the own node; When the receiving unit receives the predicted information of communication unavailability, the transmitting unit transmits a message including information indicating that the next hop node is the fifth node, information indicating that a destination node that is a destination of communication is the third node, and information on the transmission power of the own node. A first node according to claim 1 or 2.

4. The control unit determines the transmission power of the first node based on location information of the first node and the location information of the second node. A first node according to any one of claims 1 to 3.

5. Upon receiving a message addressed to the third node from the second node, the fourth node predicts the communication failure between the second node and the third node. A first node according to any one of claims 1 to 4.

6. The fourth node is present between the second node and the third node, and when the fourth node cannot receive a message transmitted from the second node, the fourth node predicts the communication failure between the second node and the third node. A first node according to any one of claims 1 to 4.

7. A transmitter for transmitting data from the node to a third node via the second node in a network, the data being transmitted to the second node; a receiving unit that receives information of a predicted communication failure from a fourth node that predicts a communication failure between the second node and the third node based on a position of the second node, a position of the third node, and a transmission range when the second node transmits the data; a control unit that, when receiving the predicted communication unavailability information, selects a fifth node from among the plurality of nodes to replace the second node based on positions between the plurality of nodes in the network and the transmission ranges of each of the plurality of nodes, and controls the node to transmit the data to the third node via the fifth node; A first node comprising:

8. A first node, a second node, a third node, a fourth node, and a fifth node, The first node is a first transmitting unit configured to transmit data from the first node to the third node via the second node in a network; a first receiving unit that receives information of a predicted communication failure from a fourth node that predicts a communication failure between the second node and the third node based on a distance between the second node and the third node and a transmission power of the second node; a control unit that, when receiving the predicted information of communication impossibility, selects a fifth node to replace the second node from among the plurality of nodes based on distances between the plurality of nodes in the network and the transmission power of each of the plurality of nodes, and controls the node to transmit the data to the third node via the fifth node; The second node is A second receiving unit that receives the data from the first node; a second transmission unit that transmits the data to the third node; the second receiving unit does not receive the data from the first node when the communication failure is predicted, the second transmission unit, when the communication failure is predicted, does not transmit the data to the third node; The third node is a third receiving unit that receives the data from the second node; the third receiving unit receives the data from the fifth node when the communication failure is predicted, The fourth node is a prediction unit that predicts the communication failure based on a distance between the second node and the third node and the transmission power of the second node; a fourth transmission unit that transmits information of the predicted communication impossibility to the first node, The fifth node is a fifth receiving unit that receives the data from the first node when the communication failure is predicted; and a fifth transmission unit that transmits the data to the third node when the communication failure is predicted. Network system.

9. transmitting data from a first node to a second node in a network for transmitting the data to a third node via the second node; receiving information of a predicted communication failure from a fourth node that predicts a communication failure between the second node and the third node based on a distance between the second node and the third node and a transmission power of the second node; When receiving the predicted communication failure information, selecting a fifth node to replace the second node from among the plurality of nodes based on distances between the plurality of nodes in the network and the transmission power of each of the plurality of nodes, and controlling the data to be transmitted from the node to the third node via the fifth node; A method in a first node comprising:

10. transmitting data from a first node to a second node in a network for transmitting the data to a third node via the second node; receiving information of a predicted communication failure from a fourth node that predicts a communication failure between the second node and the third node based on a distance between the second node and the third node and a transmission power of the second node; When receiving the predicted communication failure information, selecting a fifth node to replace the second node from among the plurality of nodes based on distances between the plurality of nodes in the network and the transmission power of each of the plurality of nodes, and controlling the data to be transmitted from the node to the third node via the fifth node; A first node program that causes a computer to execute the above.

Images