JP2005142959A - Ad hoc communication system, its communication device and method for determining destination - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform communication with high security in accordance with the configuration of organization at the utilization place. <P>SOLUTION: Each mobile node a-f becomes a source node. If a plurality of neighboring nodes exist when an address node belongs to other group, the neighboring node is selected as the destination node according to a priority of the condition: (1) a node of the same group and the same or upper class, (2) a node of a different group and the same or upper class, and (3) a node of lower class. Each mobile node 1-f transmits a packet to a selected destination node. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ad hoc communication system that forms an ad hoc network in which a plurality of mobile nodes dynamically establish a packet transmission path, a communication device thereof, and a transmission destination determination method.

  Conventionally, in an ad hoc network, a plurality of mobile nodes relay packets to enable communication between mobile nodes that cannot perform direct communication.

  When such relay communication is performed, there are generally a plurality of routes through which packets can be relayed. Which of the plurality of transmission paths is used for packet transmission is determined in consideration of reachability to the destination node and the cost of the path in the conventional path control.

Non-patent documents 1 to 4 are known as documents disclosing related technologies.
David B. Johnson, 2 others, "The Dynamic Source Routing Protocol for Mobile Ad Hoc Networks (DSR)", [online], April 15, 2003, IETF MANET Working Group, [search October 29, 2003] , Internet <URL: http://www.ietf.org/internet-drafts/draft-ietf-manet-dsr-09.txt> Thomas Clausen, 1 other, "Topology Dissemination Based on Reverse-Path Forwarding (TBRPF)", [online], January 3, 2003, IETF MANET Working Group, [October 29, 2003 search], Internet <URL : http://www.ietf.org/internet-drafts/draft-ietf-manet-olsr-11.txt> R. Ogier, 2 others, "Optimized Link State Routing Protocol", [online], October 14, 2003, Mobile Ad-Hoc Networks Working Group, [October 29, 2003 search], Internet <URL: http : //www.ietf.org/internet-drafts/draft-ietf-manet-tbrpf-11.txt> C. Perkins, two others, "Ad hoc On-Demand Distance Vector (AODV) Routing", [online], July 2003, Network Working Group, [October 29, 2003 search], Internet <URL: http : //www.ietf.org/rfc/rfc3561.txt>

  According to conventional routing control, all mobile nodes belonging to the network can be relay nodes. For this reason, there has been a security inconvenience such as the possibility of data being stolen.

  In addition, the configuration of an organization such as a company using a network cannot be reflected in the path control.

  The present invention has been made in consideration of such circumstances, and an object of the present invention is to enable communication with high security in accordance with the configuration of the organization of the user.

  In order to achieve the above object, according to the present invention, any one of the group identifiers defined for each of the plurality of groups is given, and any of the node class values defined for each of the plurality of classes In an ad hoc communication system in which an ad hoc network is formed by a plurality of mobile nodes to which the mobile node is assigned, each mobile node has a means for determining a route through which a packet can be transferred to another mobile node, and the other mobile node as a destination node. A destination node to which the packet is to be transmitted is determined from among the neighboring nodes including the destination node and a communicable mobile node having a route to the destination node. Determining means, and means for transmitting the packet to the destination node, and the determining means When the group identifier is different between the source node and the destination node, if there is a neighboring node having the same group identifier as the source node and having a higher or lower node class value than the source node Neighboring node is determined as the destination node, there is no neighboring node that matches the above condition, the source node and group identifier are the same, and the node class value is the same for the source node If a node exists, the neighboring node is determined as the destination node, there is no neighboring node that matches each of the above conditions, the group identifier is different from the source node, and the node class with respect to the destination node If there is a neighboring node having a higher value or a peer value, the neighboring node is determined as the destination node, and the above conditions are met. There is no neighboring node, the group identifier is different from the source node, and the group identifier is the same as the neighboring node or the source node whose node class value is lower than the destination node. If there is a neighboring node having a lower node class value, the neighboring node is determined as the destination node.

  By taking such measures, if each mobile node becomes a source node and the destination node belongs to another group and there are multiple neighboring nodes, (1) the group is the same, and Neighboring nodes are selected as transmission destination nodes in the order of priority: node class is higher or peer, (2) group is different, node class is higher or peer, and (3) node class value is lower. Each mobile node transmits a packet to the selected destination node. Accordingly, a packet transmission path is selected in consideration of the group to which each mobile node belongs and the class of each mobile node.

  According to the present invention, since the group to which each mobile node belongs and the class of each mobile node can be considered in selecting a packet transmission path, communication can be performed with high security in accordance with the configuration of the user organization. Is possible.

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

(First embodiment)
FIG. 1 is a diagram showing a configuration of an ad hoc communication system according to the first embodiment of the present invention.
As shown in FIG. 1, the ad hoc communication system according to the first embodiment includes a plurality of mobile nodes that can individually move. These mobile nodes can physically communicate with all adjacent mobile nodes. Each mobile node can be uniquely identified by a network address. Each mobile node belongs to one of a plurality of groups. A group can be uniquely identified by a group identifier. In addition, each mobile node is classified and a node class value is given. The node class value is represented by a positive integer, and a smaller value corresponds to a higher class. However, the node class value may be a system that can discriminate the hierarchical relationship of the class, and can be appropriately changed such that a larger value corresponds to a higher class. This node class value need not be unique.

  In FIG. 1, six mobile nodes of mobile nodes a to f are shown. The mobile nodes a, b, and c belong to the first group, and the mobile nodes d, e, and f belong to the second group. Assume that “1” is assigned as a group identifier to the first group, and “2” is assigned as a group identifier to the second group. The mobile nodes a and d are assigned “1” as the node class value, the mobile nodes b and c are assigned “2” as the node class value, and the mobile nodes e and f are “3” as the node class value. Is assumed to be granted. In FIG. 1, the group identifier and node class value for each mobile node are illustrated in the form of “group identifier: node class value”. Further, the straight line connecting the mobile nodes in FIG. 1 indicates the relationship of the mobile nodes that can communicate directly.

  The mobile node also functions as a router. When a packet destined for another mobile node is received, the mobile node forwards the packet to another mobile node. With this function, an ad hoc network is configured by enabling communication through an arbitrary path following the straight line shown in FIG.

  Although it is arbitrary what kind of form this ad hoc communication system is used, for example, use as a communication system in a company is assumed. In this case, for example, it is conceivable that separate groups are used for each department of the company, and mobile nodes used by employees belonging to each department are operated as belonging to the group corresponding to the department. Furthermore, in this case, it is possible to set the node class value higher for mobile nodes used by employees with higher positions. Specifically, the node class value of the mobile node used by the general manager is “1”, the class value of the mobile node used by the section manager is “2”, and the node class value of the mobile node used by general members is “ 3 ”and so on.

FIG. 2 is a functional block diagram showing the configuration of the communication device used as the mobile node in FIG.
As shown in FIG. 2, the communication device includes a radio unit 1, a route search unit 2, a route table storage unit 3, a group identifier storage unit 4, a node class value storage unit 5, a transmission destination determination unit 6, a communication control unit 7, A buffer 8 and an interface unit 9 are included.

  The wireless unit 1 performs wireless communication with other mobile nodes.

  The route search unit 2 searches for a physically communicable route via the wireless unit 1. The route search unit 2 creates a route table indicating the result of the search. The route table storage unit 3 stores the above route table.

  The group identifier storage unit 4 stores a group identifier of a group to which a mobile node to which this communication device is applied belongs. The node class value storage unit 5 stores the node class value assigned to the mobile node to which this communication device is applied.

  The transmission destination determination unit 6 determines the transmission destination of the packet in consideration of the routing table, the group identifier, and the node class value stored in the routing table storage unit 3, the group identifier storage unit 4, and the node class value storage unit 5.

  The communication control unit 7 stores the packet in the buffer 8 when the wireless unit 1 receives a packet destined for the communication device. Further, the communication control unit 7 transmits a packet destined for another mobile node stored in the buffer 8 to the transmission destination determined by the transmission destination determination unit 6 via the wireless unit 1.

  The interface unit 9 acquires a packet destined for another mobile node from a predetermined information processing unit (not shown) and stores it in the buffer 8. The interface unit 9 extracts a packet destined for the mobile node to which the communication apparatus is applied from the buffer 8 and sends the packet to the information processing unit. The information processing unit may be provided inside the communication device or may be provided in another device connected to the communication device.

  Note that the route search unit 2, the transmission destination determination unit 6, and the communication control unit 7 can be realized, for example, by causing a processor to execute a program describing processing as each of the above-described units. As the routing table storage unit 3, the group identifier storage unit 4, the node class value storage unit 5, and the buffer 8, for example, a semiconductor memory can be used.

Next, the operation of the ad hoc communication system according to the first embodiment configured as described above will be described.
Each mobile node individually performs the operations described below.
First, the route table is created by the route search unit 2 searching for a route, for example, as in an existing ad hoc network. This routing table is stored in the routing table storage unit 3.

  On the other hand, if a packet to be transmitted from the data processing unit to another mobile node is output, this packet is stored in the buffer 8 by the interface unit 9. If a packet designating another mobile node as a destination is wirelessly transmitted, the packet is received by the wireless unit 1 and stored in the buffer 8 by the communication control unit 7.

  In the following description, the mobile node designated as the destination of the packet is the destination node, the mobile node transmitting the packet stored in the buffer 8 as described above to the other mobile node is the source node, and the source node is the packet A destination mobile node is referred to as a destination node, and a mobile node (including a destination node) that can communicate with the source node is referred to as a neighboring node.

Now, each mobile node becomes a transmission source node when a packet designating another mobile node as a destination is stored in the buffer 8 as described above. Then, the mobile node executes the processing as shown in FIG. 3 in response to the fact that it has become the transmission node.
FIG. 3 is a flowchart showing a processing procedure in which the transmission destination determination unit 6 of the transmission node determines the transmission destination node. The transmission destination determination unit 6 executes the processing shown in FIG. 3 for each of the packets stored in the buffer 8.
In step Sa1, the transmission destination determination unit 6 confirms whether direct communication with the destination node is possible. If direct communication is impossible, the transmission destination determination unit 6 proceeds from step Sa1 to step Sa2. In step Sa2, the transmission destination determination unit 6 confirms whether there is a neighboring node having a route to the destination node with reference to the route table. If there is no corresponding neighboring node, the packet cannot be sent to the destination node at present. Therefore, the transmission destination determination unit 6 abandons the determination of the transmission destination node and ends the processing of FIG.

  By the way, if direct communication with the destination node is possible, the transmission destination determination unit 6 proceeds from step Sa1 to step Sa3. In step Sa <b> 3, the transmission destination determination unit 6 confirms whether the group identifier of the destination node is the same as the group identifier stored in the group identifier storage unit 4. If the group identifiers are different, in step Sa4, the transmission destination determination unit 6 confirms whether there is a neighboring node having a route to the destination node with reference to the route table.

  If the group identifiers are the same, or if there is no neighboring node having a route to the destination node although the group identifiers are different, the transmission destination determination unit 6 proceeds from step Sa3 or step Sa4 to step Sa5. In step Sa5, the transmission destination determination unit 6 selects the destination node as the transmission destination node, and ends the processing.

  On the other hand, direct communication with the destination node is impossible, or direct communication with the destination node is possible, but the group identifier is different and there is a neighboring node having a route to the destination node. In this case, the transmission destination determination unit 6 proceeds from step Sa2 or step Sa4 to step Sa6. In step Sa6, the transmission destination determination unit 6 confirms whether there is a neighboring node that matches the first condition. Here, the first condition is a condition that “the group identifier is the same as that of the transmission node and the node class value is higher than the transmission node”. If there is a neighboring node that satisfies the first condition, the transmission destination determination unit 6 proceeds from step Sa6 to step Sa7. In step Sa7, the transmission destination determination unit 6 selects one of the neighboring nodes that matches the first condition as a transmission destination node, and ends the processing.

  If there is no neighboring node that matches the first condition, the transmission destination determination unit 6 proceeds from step Sa6 to step Sa8. In step Sa8, the transmission destination determination unit 6 confirms whether there is a neighboring node that satisfies the second condition. Here, the second condition is a condition that “the group identifier is the same as that of the transmission node and the node class value is the same for the transmission node”. If there is a neighboring node that satisfies the second condition, the transmission destination determination unit 6 proceeds from step Sa8 to step Sa9. In step Sa9, the transmission destination determination unit 6 selects one of the neighboring nodes that matches the second condition as the transmission destination node, and ends the process.

  If there is no neighboring node that matches the first or second condition, the transmission destination determination unit 6 proceeds from step Sa8 to step Sa10. In step Sa10, the transmission destination determination unit 6 confirms whether there is a neighboring node that satisfies the third condition. Here, the third condition is a condition that “the sending node and the group identifier are different and the node class value is higher or the same as the destination node”. If there is a neighboring node that matches the third condition, the transmission destination determination unit 6 proceeds from step Sa10 to step Sa11. In step Sa11, the transmission destination determination unit 6 selects one of the neighboring nodes that matches the third condition as a transmission destination node, and ends the process.

  If there is no neighboring node that matches any of the first to third conditions, the transmission destination determination unit 6 proceeds from step Sa10 to step Sa12. In step Sa12, the transmission destination determination unit 6 confirms whether there is a neighboring node that satisfies the fourth condition. Here, the fourth condition is a condition that “the sending node and the group identifier are different and the node class value is lower than the destination node”. If there is a neighboring node that matches the fourth condition, the transmission destination determination unit 6 proceeds from step Sa12 to step Sa13. In step Sa13, the transmission destination determination unit 6 selects one of the neighboring nodes that matches the fourth condition as a transmission destination node, and ends the processing.

  If there is no neighboring node that matches any of the first to fourth conditions, the transmission destination determination unit 6 proceeds from step Sa10 to step Sa14. In step Sa14, the transmission destination determination unit 6 determines that the neighboring node does not meet any of the first to fourth conditions, that is, “the transmission node and the group identifier are the same and the node class value is lower than the transmission node”. One of the neighboring nodes that meets the above condition is selected as a transmission destination node, and the processing is terminated.

  If there are a plurality of neighboring nodes that match each condition in steps Sa7, 9, 11, 13, and 14, a neighboring node having a node class value closer to the node class value of the transmission source node is selected as the transmission destination node. . In addition, when a packet transmitted from another mobile node is transmitted to another mobile node, the mobile node that transmitted the packet is excluded from the selection targets of the transmission destination node.

  The destination node determined by the destination determination unit 6 as described above is notified to the communication control unit 7. Then, the communication control unit 7 transmits the packet stored in the buffer 8 from the wireless unit 1 to the transmission destination node.

  A specific example of communication realized by each mobile node performing the above operation will be described below. Here, a case where a packet is sent from mobile node c to mobile node e when the ad hoc network is in the state shown in FIG.

  First, in the state shown in FIG. 1, communication is physically possible by a combination of {a, d}, {a, e}, {c, d}, {c, e}. Therefore, the mobile node c and the mobile node e can communicate directly. However, the mobile node c belongs to the first group, whereas the mobile node e belongs to the second group, and the group identifiers of the respective mobile nodes are different from each other. Since mobile node c has mobile nodes a, b, d, and e that can communicate, mobile node c selects a destination node from these mobile nodes.

  Since the mobile node a has the same group identifier “1” as the mobile node c, and the node class value is “1”, which is higher than the node class value “2” of the mobile node c, the first condition It matches. Since the mobile node b has the same group identifier “1” as the mobile node c, and the node class value is “2” and is the same as the node class value “2” of the mobile node c, the second condition It matches. The mobile node d has a group identifier “2” different from that of the mobile node c, and the node class value is “1”, which is higher than the node class value “3” of the mobile node e. It matches. The mobile node e has a group identifier “2” different from that of the mobile node c, and since it is the destination node itself, the node class value is the same and meets the fourth condition.

  Thus, since there is the mobile node a as a neighboring node that matches the first condition, the mobile node c selects the mobile node a as a destination node and transmits a packet as indicated by an arrow in FIG.

  When receiving the packet transmitted from the mobile node c, the mobile node a forwards the packet to the neighboring node because the destination is another mobile node e.

  Mobile node a and mobile node e can communicate directly. However, since the mobile node a belongs to the first group, the mobile node e belongs to the second group, and the group identifiers of the respective mobile nodes are different from each other. Since the mobile node “a” has mobile nodes “b”, “d”, and “e” that can communicate with each other in addition to the mobile node c, the destination node is selected from these mobile nodes.

  The mobile node b has the same group identifier “1” as the mobile node a, and the node class value is “2”, which is lower than the node class value “1” of the mobile node a. To none of the fourth conditions. Since the mobile node d has a group identifier “2” different from that of the mobile node c, and the node class value is “1”, which is higher than the node class value “3” of the destination node e, the third condition It matches. The mobile node “e” has a group identifier “2” different from that of the mobile node “c”, and is the destination node itself and has the same node class value, and therefore satisfies the third condition.

  Thus, there is no neighboring node that matches the first condition or the second condition, and there are the mobile node d and the mobile node e as neighboring nodes that meet the third condition. The node class value “1” of the mobile node d is closer to the class value “1” of the mobile node a than the node class value “3” of the mobile node e. Accordingly, the mobile node a selects the mobile node d as a transmission destination node, and transmits a packet as indicated by an arrow in FIG.

  When the mobile node d receives the packet transmitted from the mobile node a, the destination is the other mobile node e and forwards the packet to the neighboring node.

  The mobile node d and the mobile node e can directly communicate with each other and both belong to the second group. Accordingly, the mobile node d selects the mobile node e as a transmission destination node, and transmits a packet as indicated by an arrow in FIG.

  As described above, the packet transmitted from the mobile node c arrives at the destination mobile node e via the mobile node a and the mobile node d. At this time, as is apparent from FIG. 1, the route is selected so that the transmission of the packet exceeding the group is performed between the mobile nodes having higher node class values. As a result, the probability that a route passing through a mobile node having a lower node class value is selected is reduced. As described above, if a higher node class value is set for a mobile node with higher reliability, such as setting a higher node class value for a mobile node used by a higher-level employee, the reliability It is possible to reduce the probability that a packet is relayed by a low mobile node, and security can be improved.

  In addition, even if the source node and the destination node can communicate directly, if both nodes are in different groups and there is a neighboring node with a higher node class value than the source node, this neighborhood Relay is done at the node. As a result, a packet is transmitted by forcibly interposing a mobile node having a higher node class value capable of relaying the packet. As a result, transmission / reception of a packet across a group can be checked by a higher-order mobile node than the mobile node that transmits / receives the packet.

(Second Embodiment)
FIG. 4 is a diagram showing a configuration of an ad hoc communication system according to the second embodiment of the present invention.
As shown in FIG. 4, the ad hoc communication system according to the second embodiment is configured by a plurality of mobile nodes each belonging to one of a plurality of groups, as in the first embodiment. However, in the second embodiment, a hierarchical relationship is also defined for a group, and a group class value that can determine this hierarchical relationship is set for each group. This group class value need not be unique.

  FIG. 4 shows six mobile nodes, mobile nodes a to f. The mobile nodes a and b belong to the first group, the mobile nodes c and d belong to the second group, and the mobile nodes e and f belong to the third group. It is assumed that “1” is assigned to the first group as a group identifier, and the group class value is set to “1”. Assume that “2” and “3” are assigned as group identifiers to the second group and the outgoing 3 group, respectively, and the group class value is set to “2”. It is assumed that “1” is assigned as the node class value to the mobile nodes a, c, and e, and “2” is assigned as the node class value to the mobile nodes b, d, and f. In FIG. 4, the group identifier, node class value, and group class value for each mobile node are illustrated in the form of “group identifier. Group class value: node class value”.

FIG. 5 is a functional block diagram showing a configuration of a communication device used as a mobile node in FIG. 5 that are the same as those in FIG. 2 are assigned the same reference numerals, and detailed descriptions thereof are omitted.
As shown in FIG. 5, the communication device includes a radio unit 1, a route search unit 2, a route table storage unit 3, a group identifier storage unit 4, a node class value storage unit 5, a communication control unit 7, a buffer 8, and an interface unit 9. The group class value storage unit 10 and the transmission destination determination unit 11 are included. That is, the communication device of the second embodiment includes a transmission destination determination unit 11 instead of the transmission destination determination unit 6 in the communication device of the first embodiment, and a group class value storage unit 10 is newly added. is there.

  The group class value storage unit 10 stores a group class value of a group to which a mobile node to which this communication device is applied belongs. For example, a semiconductor memory can be used as the group class value storage unit 10.

  The transmission destination determination unit 11 is stored in the group class value storage unit 10 in addition to the path table, group identifier, and node class value stored in the route table storage unit 3, the group identifier storage unit 4 and the node class value storage unit 5. The destination of the packet is determined in consideration of the group class value. The transmission destination determination unit 11 can be realized by causing a processor to execute a program describing processing for that purpose.

Next, the operation of the ad hoc communication system according to the second embodiment configured as described above will be described.
The ad hoc communication system according to the second embodiment operates in substantially the same manner as the ad hoc communication system according to the first embodiment. However, in the second embodiment, the process of determining the packet transmission destination node in each mobile node is different from that in the first embodiment.

  FIG. 6 is a flowchart showing a processing procedure in which the transmission destination determination unit 11 of the transmission node determines the transmission destination node. In FIG. 6, only the same steps as those in FIG. 3 are illustrated, and these steps are denoted by the same reference numerals.

  As illustrated in FIG. 6, the transmission destination determination unit 11 performs the same processes as those of the transmission destination determination unit 6 in steps Sa <b> 1 to Sa <b> 9. Then, when there is no neighboring node that matches the first or second condition, the transmission destination determination unit 11 performs processing different from that of the transmission destination determination unit 6 as described below.

  If there is no neighboring node that matches the first or second condition, the transmission destination determining unit 11 proceeds from step Sa8 to step Sb1. In step Sb1, the transmission destination determination unit 11 checks whether there is a neighboring node that satisfies the fifth condition. Here, the fifth condition is a condition that “the group identifier is different from the transmitting node, the group class value is higher than the transmitting node, and the node class value is higher or equal to the destination node”. If there is a neighboring node that satisfies the fifth condition, the transmission destination determination unit 11 proceeds from step Sb1 to step Sb2. In step Sb2, the transmission destination determination unit 11 selects one of the neighboring nodes that matches the fifth condition as a transmission destination node, and ends the process.

  If there is no neighboring node that matches any of the first, second, and fifth conditions, the transmission destination determining unit 11 proceeds from step Sb1 to step Sb3. In step Sb3, the transmission destination determining unit 11 checks whether there is a neighboring node that satisfies the sixth condition. Here, the sixth condition is a condition that “the group identifier value is different from the transmitting node, the group class value is higher than the transmitting node, and the node class value is lower than the destination node”. If there is a neighboring node that satisfies the sixth condition, the transmission destination determining unit 11 proceeds from step Sb3 to step Sb4. In step Sb4, the transmission destination determination unit 11 selects one of the neighboring nodes that matches the sixth condition as a transmission destination node, and ends the process.

  If there is no neighboring node that matches any of the first, second, fifth, and sixth conditions, the transmission destination determining unit 11 proceeds from step Sb3 to step Sb5. In step Sb5, the transmission destination determination unit 11 checks whether there is a neighboring node that satisfies the seventh condition. Here, the seventh condition is a condition that “the group identifier is different from the transmitting node, the group class value is the same for the transmitting node, and the node class value is higher or the same for the destination node”. If there is a neighboring node that satisfies the seventh condition, the transmission destination determination unit 11 proceeds from step Sb5 to step Sb6. In step Sb6, the transmission destination determination unit 11 selects one of the neighboring nodes that matches the seventh condition as a transmission destination node, and ends the processing.

  If there is no neighboring node that matches any of the first, second, and fifth to seventh conditions, the transmission destination determining unit 11 proceeds from step Sb5 to step Sb7. In step Sb7, the transmission destination determining unit 11 confirms whether there is a neighboring node that matches the eighth condition. Here, the eighth condition is a condition that “the transmitting node is different from the group identifier, the group class value is equal to the transmitting node, and the node class value is lower than the destination node”. If there is a neighboring node that matches the eighth condition, the transmission destination determining unit 11 proceeds from step Sb7 to step Sb8. In step Sb8, the transmission destination determination unit 11 selects one of the neighboring nodes that matches the eighth condition as a transmission destination node, and ends the process.

  If there is no neighboring node that matches any of the first, second, and fifth to eighth conditions, the transmission destination determining unit 11 proceeds from step Sb7 to step Sb9. In step Sb9, the transmission destination determining unit 11 checks whether there is a neighboring node that satisfies the ninth condition. Here, the ninth condition is that “the group identifier is the same as that of the transmission node and the node class value is lower than the transmission node”. If there is a neighboring node that satisfies the ninth condition, the transmission destination determining unit 11 proceeds from step Sb9 to step Sb10. In step Sb10, the transmission destination determination unit 11 selects one of the neighboring nodes that matches the ninth condition as a transmission destination node, and ends the process.

  If there is no neighboring node that matches any of the first, second, and fifth to ninth conditions, the transmission destination determining unit 11 proceeds from step Sb9 to step Sb11. In step Sb11, the transmission destination determining unit 11 determines that the neighboring node does not meet any of the first, second, and fifth to ninth conditions, that is, “the transmission node differs from the group identifier and the group class is different from the transmission node. One of the neighboring nodes meeting the condition “value is lower” is selected as the transmission destination node, and the processing is terminated.

  If there are a plurality of neighboring nodes that match each condition in steps Sa7, 9 and steps Sb4, 6, 8, 10, and 11, if the group class values of these neighboring nodes are different, the group of the source node A neighboring node having a group class value closer to the class value is selected as a transmission destination node. If the group class values of a plurality of neighboring nodes that match each condition are the same, a neighboring node having a node class value closer to the node class value of the transmission source node is selected as the transmission destination node. In addition, when a packet transmitted from another mobile node is transmitted to another mobile node, the mobile node that transmitted the packet is excluded from the selection targets of the transmission destination node.

  A specific example of communication realized by each mobile node performing the above operation will be described below. Here, a case where a packet is sent from the mobile node f to the mobile node a when the ad hoc network is in the state shown in FIG. 4 is illustrated.

  First, in the state shown in FIG. 4, physically {a, b}, {a, c}, {a, e}, {b, c}, {c, d}, {c, e}, {c , F}, {e, f}. Accordingly, direct communication between the mobile node f and the mobile node a is impossible. However, since the mobile node f has mobile nodes b, c, and e that can communicate in addition to the mobile node a, the destination node is selected from these mobile nodes.

  The mobile node b has a group identifier “1” different from that of the mobile node f, has a group class value “1” and is higher than the group class value “3” of the mobile node f, and further has a node class value. Is “2”, which is lower than the node class value “1” of the mobile node a, the sixth condition is satisfied. The mobile node c has a group identifier “2” different from that of the mobile node f, has a group class value “2” and is higher than the group class value “3” of the mobile node f, and further has a node class value. Is “1”, which is the same as the node class value “1” of the mobile node a, so the fifth condition is satisfied. Since the mobile node e has the same group identifier “3” as the mobile node f, and the node class value is “1”, which is higher than the node class value “2” of the mobile node f, the first condition It matches.

  Thus, since there is the mobile node e as a neighboring node that matches the first condition, the mobile node f selects the mobile node e as a transmission destination node, and transmits a packet as shown by an arrow in FIG.

When the mobile node e receives the packet transmitted from the mobile node f, since the destination is another mobile node a, the mobile node e forwards the packet to any of the neighboring nodes.
Mobile node e and mobile node a can communicate directly. However, the mobile node e belongs to the third group, whereas the mobile node a belongs to the first group, and the group identifiers of the respective mobile nodes are different from each other. Since the mobile node e has mobile nodes a and c that can communicate with each other in addition to the mobile node f, a destination node is selected from these mobile nodes.

  The mobile node a has a group identifier “1” different from that of the mobile node e, the group class value is “1”, which is higher than the group class value “3” of the mobile node e, and the destination node itself. Since the node class values are the same, the fifth condition is met. The mobile node c has a group identifier “2” different from that of the mobile node e, and the group class value is “2”, which is higher than the group class value “3” of the mobile node e. Is “1”, which is the same as the node class value “1” of the mobile node a, so the fifth condition is satisfied.

  Thus, there is no neighboring node that matches the first condition or the second condition, and there are the mobile node a and the mobile node c as neighboring nodes that meet the fifth condition. The group class value “2” of the mobile node c is closer to the class value “3” of the mobile node e than the node class value “1” of the mobile node a. Therefore, the mobile node e selects the mobile node c as a transmission destination node, and transmits a packet as shown by an arrow in FIG.

When the mobile node c receives the packet transmitted from the mobile node e, the mobile node c forwards the packet to any of the neighboring nodes because the destination is another mobile node a.
Mobile node c and mobile node a can communicate directly. However, the mobile node c belongs to the second group, whereas the mobile node a belongs to the first group, and the group identifiers of the respective mobile nodes are different from each other. Since the mobile node c has mobile nodes a, b, d, and f that can communicate in addition to the mobile node e, the destination node is selected from these mobile nodes.

  The mobile node a has a group identifier “1” different from that of the mobile node c, the group class value is “1”, which is higher than the group class value “2” of the mobile node c, and the destination node itself. Since the node class values are the same, the fifth condition is met. The mobile node b has a group identifier “1” different from that of the mobile node c, and the group class value is “1”, which is higher than the group class value “2” of the mobile node c. Is “2”, which is lower than the node class value “1” of the mobile node a, the sixth condition is satisfied. The mobile node b has the same group identifier “2” as the mobile node c, and the node class value is “2”, which is lower than the node class value “1” of the mobile node c. It matches. Since the mobile node f has a group identifier “3” different from that of the mobile node c, and the group class value is “3”, which is lower than the group class value of the mobile node c, the first, second, It does not meet any of the fifth to ninth conditions.

  Thus, there is no neighboring node that matches the first condition or the second condition, and there is a mobile node a as a neighboring node that matches the fifth condition. Therefore, the mobile node c selects this mobile node a as a destination node, and FIG. A packet is transmitted as indicated by an arrow in FIG.

  As described above, the packet transmitted from the mobile node f reaches the destination mobile node a via the mobile node e and the mobile node c. At this time, as is clear from FIG. 4, the route is selected so that the transmission of the packet exceeding the group is performed between mobile nodes having higher node class values. As a result, the probability that a route passing through a mobile node having a lower node class value is selected is reduced. As described above, if a higher node class value is set for a highly reliable mobile node, such as setting a higher node class value for a mobile node used by a higher-level employee, the reliability It is possible to reduce the probability that a packet is relayed by a low mobile node, and security can be improved.

In addition, even if the source node and the destination node can communicate directly, if both nodes are in different groups and there is a neighboring node with a higher node class value than the source node, this neighborhood Relay is done at the node. As a result, a packet is transmitted by forcibly interposing a mobile node having a higher node class value capable of relaying the packet. As a result, transmission / reception of a packet across a group can be checked by a higher-order mobile node than the mobile node that transmits / receives the packet.
Furthermore, a route that takes into account the hierarchical relationship of the groups is selected.

(Third embodiment)
The configuration of the ad hoc communication system according to the third embodiment of the present invention is the same as the configuration of the first embodiment shown in FIG. The third embodiment differs from the first embodiment in the configuration of a communication device used as a mobile node.

FIG. 7 is a functional block diagram showing the configuration of the communication apparatus according to the third embodiment. 7 that are the same as those in FIG. 2 are assigned the same reference numerals, and detailed descriptions thereof are omitted.
As shown in FIG. 7, the communication device includes a radio unit 1, a route search unit 2, a route table storage unit 3, a group identifier storage unit 4, a node class value storage unit 5, a communication control unit 7, a buffer 8, and an interface unit 9. The priority list storage unit 12 and the transmission destination determination unit 13 are included. That is, the communication device of the third embodiment includes a transmission destination determination unit 13 instead of the transmission destination determination unit 6 in the communication device of the first embodiment, and additionally includes a priority list storage unit 12. is there.

  The priority list storage unit 12 stores a priority list described regarding a mobile node to be preferentially selected as a destination node regardless of the node class value. For example, a semiconductor memory can be used as the priority list storage unit 12.

  In the priority list, one priority designation is described in the form of “group identifier: node identifier / priority”. Specifies that a group or a mobile node specified by a group identifier or a node identifier is to be preferentially selected in a form specified by priority. As the node identifier, an identifier used in physical connection for identifying a mobile node, an identifier used in the network layer, or the like can be used. If there is no need to consider either the group identifier or the node identifier, “0” is entered. The priority is also originally expressed as a positive integer, but "0" can also be entered. The priority “0” indicates that the designation of the priority selection is invalidated. By using this, it is possible to temporarily invalidate the designation of priority selection.

  The form and number of priority selections may be arbitrary. In this embodiment, there are three types of priority selection, and the priorities are “1” to “3”. The priority “1” is given priority over all other groups or mobile nodes. Accordingly, the priority selection target with the priority “1” is designated by the node identifier. For example, if the mobile node d is a priority selection target, the description “0: d / 1” is included in the priority list. The priority “2” is given priority over other mobile nodes in the case where there are a plurality of neighboring nodes that meet a certain condition. Accordingly, the priority selection target having the priority “2” is designated by the node identifier. For example, if the mobile node b is the target of priority selection, the description “0: b / 2” is included in the priority list. The priority “3” gives priority to a specific group over other groups when there are a plurality of groups to which neighboring nodes that meet a certain condition belong. Accordingly, the priority selection target having the priority “3” is designated by the group identifier. For example, if the group with the group identifier “3” is prioritized over other groups, the description “3: 0/3” is included in the priority list.

  The transmission destination determination unit 13 is stored in the priority list storage unit 12 in addition to the route table, group identifier, and node class value stored in the route table storage unit 3, the group identifier storage unit 4, and the node class value storage unit 5. The packet transmission destination is determined in consideration of the priority list. The transmission destination determination unit 13 can be realized by causing a processor to execute a program describing a process for that purpose.

Next, the operation of the ad hoc communication system according to the third embodiment configured as described above will be described.
The ad hoc communication system of the third embodiment operates in substantially the same manner as the ad hoc communication system of the first embodiment. However, in the third embodiment, the process of determining the packet transmission destination node in each mobile node is different from that in the first embodiment.

  FIG. 8 is a flowchart showing a processing procedure in which the transmission destination determination unit 13 of the transmission node determines the transmission destination node. In FIG. 8, only the same steps as those in FIG. 3 are illustrated, and these steps are denoted by the same reference numerals.

  As illustrated in FIG. 8, the transmission destination determination unit 13 performs the processing from step Sa <b> 1 to step Sa <b> 5 in the same manner as the transmission destination determination unit 6. Then, the transmission destination determining unit 13 does not proceed from step Sa2 or step Sa4 to step Sa6 but proceeds to step Sc1. In step Sc <b> 1, the transmission destination determination unit 13 confirms whether the mobile node designated as the priority “1” in the priority list exists as a neighboring node. Here, if there is no corresponding neighboring node, or if priority “1” is not specified in the priority list, the transmission destination determining unit 13 proceeds from step Sc1 to step Sa6. Thereafter, the transmission destination determination unit 13 performs the processing after step Sa6 in the same manner as the transmission destination determination unit 6. However, if there is a corresponding neighboring node, the transmission destination determining unit 13 proceeds from step Sc1 to step Sc2. In step Sc2, the transmission destination determination unit 13 selects a neighboring node designated as the priority “1” as the transmission destination node, and ends the processing of FIG.

  In the first embodiment, when there are a plurality of neighboring nodes that match any of the first to fourth conditions or a plurality of neighboring nodes that do not match any of the first to fourth conditions, the transmission source A neighboring node having a node class value closer to the node class value of the node is selected as a transmission destination node. However, in the third embodiment, the transmission destination determination unit 13 performs the processing of steps Sa7, 9, 11, 13, and 14 according to the processing procedure shown in FIG.

FIG. 9 is a flowchart showing a processing procedure of the transmission destination determination unit 13 for selecting one of the neighboring nodes that match each condition.
In step Sd1, the transmission destination determination unit 13 confirms whether there are a plurality of neighboring nodes that match each condition. If there are a plurality of corresponding neighboring nodes, the transmission destination determining unit 13 proceeds from step Sd1 to step Sd2. In step Sd2, the transmission destination determination unit 13 confirms whether there is any of the neighboring nodes belonging to the group for which the priority “3” is set.

  If there is a neighboring node belonging to the group for which the priority “3” is set, the transmission destination determination unit 13 proceeds from step Sd2 to step Sd3. In step Sd3, the transmission destination determining unit 13 extracts all neighboring nodes belonging to the group for which the priority “3” is set. In step Sd4, the transmission destination determination unit 13 confirms whether or not there are a plurality of the extracted neighboring nodes.

  If a plurality of neighboring nodes are extracted in step Sd3, the transmission destination determining unit 13 proceeds from step Sd4 to step Sd5. If there is no neighboring node belonging to the group for which priority “3” is set, the transmission destination determination unit 13 proceeds from step Sd2 to step Sd5. In step Sd5, the transmission destination determining unit 13 confirms whether there is any of the neighboring nodes satisfying the conditions so far set with the priority “2”. If there is a neighboring node for which the priority “2” is set, the transmission destination determining unit 13 proceeds from step Sd5 to step Sd6. In step Sd6, the transmission destination determination unit 13 selects a neighboring node with the priority “2” as a transmission destination node, and ends the processing shown in FIG. On the other hand, if there is no neighboring node for which the priority “2” is set, the transmission destination determining unit 13 proceeds from step Sd5 to step Sd7. In step Sd7, the transmission destination determination unit 13 selects a node having a node class value closer to the node class value of the transmission source node among the neighboring nodes that satisfy the above conditions as a transmission destination node. The process shown in FIG. 9 ends.

  If there is only one neighboring node that matches any of the first to fourth conditions or one neighboring node that does not match any of the first to fourth conditions, or extracted in step Sd3. If there is only one neighboring node, the transmission destination determining unit 13 proceeds from step Sd1 or step Sd4 to step Sd8. In step Sd8, the transmission destination determining unit 13 selects only one neighboring node as a transmission destination node, and the processing of FIG.

A specific example of communication realized by each mobile node performing the above operation will be described below.
For example, a case where a packet is sent from the mobile node c to the mobile node e when the ad hoc network is in the state shown in FIG. 10 similar to FIG. Here, it is assumed that the priority list stored in the priority list storage unit 12 of the mobile node c is described as “0: d / 1”.

  Originally, as described in the first embodiment, the mobile node c selects the mobile node a as a transmission destination node, and sends a packet to the mobile node a as indicated by a broken line arrow. However, here, the description of the priority list of “0: d / 1” specifies that mobile node d is given priority over all mobile nodes. For this purpose, the mobile node c selects the mobile node d as a transmission destination node, and sends a packet to the mobile node d as indicated by a solid line arrow.

  FIG. 11 illustrates a case where there are two mobile nodes a and b as neighboring nodes that meet the first condition for the mobile node c that is the transmission source node. Here, it is assumed that the priority list stored in the priority list storage unit 12 of the mobile node c is described as “0: b / 2”. The description of the priority list “0: b / 2” specifies that mobile node b is given priority over other mobile nodes that meet the same conditions. For this purpose, the mobile node c selects the mobile node b as a destination node, and sends a packet to the mobile node b as indicated by an arrow.

  FIG. 12 illustrates a case where there are two mobile nodes “b” and “c” as neighboring nodes satisfying the third condition for the mobile node “a” that is the transmission source node. Here, it is assumed that the priority list stored in the priority list storage unit 12 of the mobile node a is described as “3: 0/3”. The description of the priority list “3: 0/3” specifies that the mobile node belonging to the group with the group identifier “3” is given priority over the mobile nodes of other groups that match the same condition. Yes. For this purpose, the mobile node a selects the mobile node c belonging to the group with the group identifier “3” as a transmission destination node, and sends a packet to the mobile node c as indicated by an arrow.

  Thus, basically, an appropriate route can be selected as described in the first embodiment by an operation similar to that of the first embodiment, but an exceptional route can be appropriately selected. is there. Therefore, flexible operation in accordance with the circumstances of the application organization can be performed.

Each of the above embodiments can be modified as follows.
In each of the above embodiments, an algorithm for determining a route in the group when the source node and the destination node belong to the same group is arbitrary, such as using an algorithm used in an existing ad hoc network. Can be changed.
The third embodiment is based on the second embodiment, and can also be realized by adding a change similar to the change to the first embodiment in the third embodiment. In this case, when mobile nodes belonging to different groups having the same group class value are candidates for the destination node, priority can be applied such that mobile nodes belonging to a specific group are preferentially selected.

  In each of the above embodiments, the group identifier is, for example, “1.0” for the first part, “2.0” for the second part, “1.1” for the first part first section, and the second part first. The section is set to “1.2”, the second section, the first section is “2.1”, the second section, the second section is “2.2”, etc. Alternatively, each mobile node may determine a destination node so that packet transfer is performed using a route according to the organization system as much as possible.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The figure which shows the structure of the ad hoc communication system which concerns on the 1st Embodiment of this invention. The functional block diagram which shows the structure of the communication apparatus utilized as a mobile node in FIG. The flowchart which showed the process sequence which the transmission destination determination part 6 of a transmission node determines a transmission destination node. The figure which shows the structure of the ad hoc communication system which concerns on the 2nd Embodiment of this invention. The functional block diagram which shows the structure of the communication apparatus utilized as a mobile node in FIG. The flowchart which showed the process sequence which the transmission destination determination part 11 of a transmission node determines a transmission destination node. The functional block diagram which shows the structure of the communication apparatus which concerns on 3rd Embodiment. The flowchart which showed the process sequence which the transmission destination determination part 13 of a transmission node determines a transmission destination node. The flowchart which shows the process sequence of the transmission destination determination part 13 for selecting one of the neighboring nodes which meet each condition. The figure which shows the specific example of communication by 3rd Embodiment. The figure which shows the specific example of communication by 3rd Embodiment. The figure which shows the specific example of communication by 3rd Embodiment.

Explanation of symbols

  a, b, d, e, f ... mobile node, 1 ... radio unit, 2 ... route search unit, 3 ... route table storage unit, 4 ... group identifier storage unit, 5 ... node class value storage unit, 6 ... destination Determining unit, 7 ... communication control unit, 8 ... buffer, 9 ... interface unit, 10 ... group class value storage unit, 11 ... destination determination unit, 12 ... priority list storage unit, 13 ... destination determination unit.

Claims (6)

An ad hoc network is provided by a plurality of mobile nodes to which one of group identifiers assigned to each of a plurality of groups is assigned and one of node class values set to each of a plurality of classes is assigned In the ad hoc communication system forming
Each mobile node
Means for determining a path through which a packet can be forwarded to another mobile node;
When a packet having another mobile node as a destination node is acquired and becomes a transmission source node, the packet is transmitted from the destination node and neighboring nodes including a communicable mobile node having a route to the destination node Determining means for determining a destination node as a destination;
Means for transmitting the packet to the destination node;
And when the group identifiers of the transmission source node and the destination node are different,
If there is a neighboring node whose group identifier is the same as that of the source node and whose node class value is higher or peer to the source node, the neighboring node is determined as the destination node;
If there is no neighboring node that matches the above condition, a group identifier is different from the source node, and there is a neighboring node having a higher or similar node class value to the destination node, the neighboring node is Decide on the destination node,
There is no neighboring node that matches each of the above conditions, the source node and the group identifier are different, and the group identifier is the same as the neighboring node or the source node whose node class value is lower than the destination node. An ad hoc communication system, wherein if there is a neighboring node whose node class value is lower than that of the source node, the neighboring node is determined as the destination node. An ad hoc network is provided by a plurality of mobile nodes to which one of group identifiers assigned to each of a plurality of groups is assigned and one of node class values set to each of a plurality of classes is assigned In the transmission destination determination method for determining the destination node to which each mobile node is a packet transmission destination from among the destination nodes and neighboring nodes including a mobile node capable of communication having a route to the destination node.
When the group identifiers of the source node and the destination node are different,
If there is a neighboring node whose group identifier is the same as that of the source node and whose node class value is higher or peer to the source node, the neighboring node is determined as the destination node;
If there is no neighboring node that matches the above condition, a group identifier is different from the source node, and there is a neighboring node having a higher or similar node class value to the destination node, the neighboring node is Decide on the destination node,
There is no neighboring node that matches each of the above conditions, the source node and the group identifier are different, and the group identifier is the same as the neighboring node or the source node whose node class value is lower than the destination node. A destination determination method, wherein if there is a neighboring node whose node class value is lower than the source node, the neighboring node is determined as the destination node. In the ad hoc communication system in which an ad hoc network is formed by a plurality of mobile nodes to which any one of a plurality of group identifier values is given and any of the group identifiers determined for each of the plurality of groups is given. In a communication device used as a mobile node,
Means for determining a path through which a packet can be forwarded to another mobile node;
When a packet having another mobile node as a destination node is acquired and becomes a transmission source node, the packet is transmitted from the destination node and neighboring nodes including a communicable mobile node having a route to the destination node Determining means for determining a destination node as a destination;
Means for transmitting the packet to the destination node;
And when the group identifiers of the transmission source node and the destination node are different,
If there is a neighboring node whose group identifier is the same as that of the source node and whose node class value is higher or peer to the source node, the neighboring node is determined as the destination node;
If there is no neighboring node that matches the above condition, a group identifier is different from the source node, and there is a neighboring node having a higher or similar node class value to the destination node, the neighboring node is Decide on the destination node,
There is no neighboring node that matches each of the above conditions, the source node and the group identifier are different, and the group identifier is the same as the neighboring node or the source node whose node class value is lower than the destination node. In addition, if there is a neighboring node whose node class value is lower than that of the transmission source node, the communication apparatus determines the neighboring node as the transmission destination node. Each of a plurality of groups each given one of a plurality of group class values is given one of a plurality of group identifiers, and one of a plurality of node class values is given In a communication device used as the mobile node in an ad hoc communication system that forms an ad hoc network with mobile nodes,
Means for determining a path through which a packet can be forwarded to another mobile node;
When a packet having another mobile node as a destination node is acquired and becomes a transmission source node, the packet is transmitted from the destination node and neighboring nodes including a communicable mobile node having a route to the destination node Determining means for determining a destination node as a destination;
Means for transmitting the packet to the destination node;
And when the group identifiers of the transmission source node and the destination node are different,
If there is a neighboring node whose group identifier is the same as that of the source node and whose node class value is higher or peer to the source node, the neighboring node is determined as the destination node;
There is no neighboring node that matches the above condition, the group identifier is different from the source node, the group class value is higher than the source node, and the node class value is higher or equal to the destination node. If there is a neighboring node that is, determine the neighboring node as the destination node,
There is no neighboring node that matches each of the above conditions, the source node and the group identifier are different, the group class value is higher than the source node, and the node class value is lower than the destination node. If there is a neighboring node, determine that neighboring node as the destination node;
There is no neighboring node that matches each of the above conditions, the group identifier is different from the source node, the group class value is the same as the source node, and the node class value is higher than the destination node. If there is a neighboring node that is a peer, determine that neighboring node as the destination node;
There is no neighboring node that matches each of the above conditions, the group identifier is different from the source node, the group class value is the same for the source node, and the node class value is lower for the destination node. If there is a neighboring node, determine that neighboring node as the destination node;
There is no neighboring node that matches each of the above conditions, the source node and the group identifier are different, and the group identifier is the same as the neighboring node or the source node whose node class value is lower than the destination node. In addition, if there is a neighboring node whose node class value is lower than that of the transmission source node, the communication apparatus determines the neighboring node as the transmission destination node.   5. The communication apparatus according to claim 3, wherein the determination unit unconditionally determines the mobile node as the transmission destination node when a mobile node designated in advance is included in a neighboring node. 6. .   5. The determination unit according to claim 3, wherein the determination unit determines the mobile node as the transmission destination node when the mobile node designated in advance is included in a neighboring node that meets a predetermined condition. The communication device described.

Images