KR100597409B1 - Method and apparatus for configuring routing path in a mobile ad hoc network - Google Patents

Abstract

The present invention relates to a method and apparatus for establishing a routing path for group communication in a mobile ad hoc network.

In accordance with another aspect of the present invention, a method for establishing a routing path for group communication includes receiving a group communication initialization packet including a source node address, a group address, an address of group members, and a distance value from a source node to each group member; Resetting each distance value included in the initialization packet by one hop, and selectively resetting the group communication initialization packet having the distance value reset according to the difference between the reset distance value and the distance value from itself to each group member. Broadcasting, and after broadcasting the group communication initialization packet, relaying data packets between the same source node and the same group members for group communication.

According to the present invention, it is possible to reduce waste of network resources in performing group communication in a mobile ad hoc network.

Ad hoc network, group communication, routing

Description

Method and apparatus for configuring routing path in a mobile ad hoc network

1 is a diagram for explaining group communication using conventional unicast.

2 is a diagram for explaining group communication using conventional broadcast.

3 is a diagram illustrating a routing process according to an embodiment of the present invention.

4 is a diagram illustrating an embodiment of information set in an initialization packet in a table format.

5A illustrates a control message of OLSR according to an embodiment of the present invention.

5B is a diagram illustrating a topology table of OLSR according to an embodiment of the present invention.

6A is a diagram illustrating information of an initialization packet that has passed one hop.

FIG. 6B is a diagram for describing whether to transmit an initialization packet whose distance information is reset.

6C is a diagram illustrating information of an initialization packet that has passed two hops.

7 is a block diagram illustrating a network device according to an embodiment of the present invention.

8 is a flowchart illustrating a process of transmitting an initialization packet by a source node.

9 is a flowchart illustrating a process of delivering an initialization packet of a node that has received an initialization packet.

<Explanation of symbols on main parts of the drawings>

310: control unit 320: storage unit

330: transceiver

The present invention relates to a method and apparatus for setting a routing path in a mobile ad hoc network, and more particularly, to a method and apparatus for setting a routing path for group communication in a mobile ad hoc network.

A mobile ad hoc network (MANET) secures communication using a wireless link without being based on an infrastructure between mobile network devices (hereinafter referred to as nodes). It is a network.

Nodes having a common interest among nodes scattered on such a network may form a group to perform their own communication. Nodes belonging to the same group share the same data, and communication between the nodes for this can be achieved through unicast or broadcast.

1 is a diagram for explaining group communication using conventional unicast.

The illustrated nodes belong to a mobile ad hoc network, of which shaded nodes form a group (hereinafter, nodes belonging to a specific group are called group members). Also, when node 1 is referred to as a source node, nodes 2 to 6 are in one hop region from the source node, and nodes 7 to 13 are in two hop regions from the source node.

The source node unicasts data to each group member to send to the group members. In this case, nodes 2 and 3 in the 1-hop region may receive data packets directly from the source node, but nodes 8 to 10 in the 2-hop region cannot receive data packets directly from the source node. Accordingly, the source node transmits the data packet by setting a relay that can relay the data packet transmission to the nodes 8 to 10 through the previously obtained routing information.

In the figure, node 4 is the relay for node 10 and node 3 is the relay for node 8 and node 9. Therefore, the source node unicasts the data packet to node 10 to node 4, and node 4 unicasts it to node 10. Similarly, data packets to be sent to nodes 8 and 9 can be relayed through note 3. This conveys the same data from the source node to each group member.

As such, when transmitting a data packet by unicast to all group members, the source node should unicast as many as the group members except itself. In addition, like the relationship between Rhodo 1 and Node 3, in some cases, the same data packet may be delivered multiple times along the same path. In particular, considering that each node delivers a data packet while reserving network resources through Request to Send / Clear to Send (RTS / CTS), it may be necessary to repeatedly use the same unicast for group communication. It's a waste of money.

 Therefore, for group communication, it is more effective to use broadcast than unicast.

2 is a diagram for explaining group communication using conventional broadcast.

The nodes shown belong to a mobile ad hoc network, of which shaded nodes form a group. In addition, when node 1 is referred to as a source node, nodes 2 to 6 are in one hop region from the source node, and nodes 7 to 13 are in two hop regions from the source node.

The source node broadcasts a data packet for delivery to group members, and neighbor nodes that receive it also broadcast it. At this time, in order to prevent the data packet from being broadcast indefinitely, the source node sets the distance from the group member farthest from the group member belonging to the same group as the transmission limit distance of the broadcast. When a data packet having a transmission limit distance is broadcast, a distance value set in the data packet decreases by 1 as each node passes through the node, and transmission of the data packet stops when the distance value set in the data packet becomes 0.

For example, in the illustrated example, the group members farthest from the source node are nodes 8 to 10 and the distance from the source node is two hops. The source node broadcasts by setting the broadcast forwarding limit to 2 for the data packet to be forwarded. When the broadcasted data packet is delivered to the nodes 2 through 6, the nodes 2 through 6 decrease the distance value set in the received data packet by 1 and broadcast it to their neighbor nodes. Nodes 7 to 13 that receive this also reduce the distance set in the received data packet by one. At this time, since the distance value set for the data packet becomes 0, the nodes 7 to 13 stop the transmission of the received data packet.

In this way, unlike the case of using unicast, the use of broadcast prevents waste of network resources due to repeated transmission of the same data. However, even with this method, if the group members are not uniformly distributed in a square as shown in the drawing, data is spread to the region 110 where the group members do not exist, thereby causing waste of network resources.

Therefore, when performing group communication in a mobile ad hoc network, a routing method is required to reduce waste of network resources.

An object of the present invention is to reduce the waste of network resources in performing group communication in a mobile ad hoc network.

The objects of the present invention are not limited to the above-mentioned objects, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, a routing path establishment method for group communication according to an embodiment of the present invention includes a source node address, a group address, an address of group members and a distance value from the source node to each of the group members. Generating a group communication initialization packet; and broadcasting the initialization packet.

In order to achieve the above object, a routing path establishment method for group communication according to an embodiment of the present invention includes a source node address, a group address, an address of group members and a distance value from the source node to each of the group members. Receiving a group communication initialization packet, resetting each distance value included in the initialization packet by one hop, and according to a difference between the reset distance value and a distance value from itself to each group member. Selectively broadcasting a group communication initialization packet whose distance value has been reset, and relaying a data packet between the source node and the group members for group communication after broadcasting the group communication initialization packet; do.

In order to achieve the above object, a network device according to an embodiment of the present invention generates a group communication initialization packet including a source node address, a group address, an address of group members, and a distance value from the source node to each of the group members. A control unit, and a transceiver for broadcasting the generated initialization packet.

In order to achieve the above object, a network device according to an embodiment of the present invention receives a group communication initialization packet including a source node address, a group address, an address of group members, and a distance value from the source node to each of the group members. A group communication in which the distance value is reset according to a difference between the reset value and the distance value included in the initialization packet, and each distance value included in the initialization packet decreases by one hop, and the distance value between the reset distance value and the distance value from itself to each group member. And selectively broadcasting the initialization packet through the transceiver, and after the group communication initialization packet is broadcast, relaying a data packet between the source node and the group members for group communication.

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and those of ordinary skill in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a diagram illustrating a routing process according to an embodiment of the present invention.

The illustrated nodes belong to a mobile ad hoc network, of which shaded nodes form a group, and node 1 operates as a source node. In addition, the arrow and the solid line in the figure means that the distance between each node is one hop. For example, the distance between node 1 and node 2 through node 6 is 1 hop, and the distance between node 1 and node 7 through node 13 is 2 hops. The arrow also indicates the transmission path of the packet.

A source node (node 1) that wants to send a data packet to group members generates a group communication initialization packet (hereinafter referred to as an initialization packet) for establishing a routing path of the data packet. In the initialization packet, information on an address of the source node, a group address, an address of each group member, and a distance from the source node to each group member is set. In FIG. 4, an embodiment of information set in the initialization packet is illustrated in a table format, based on the situation of FIG. 3.

As the source node address, an address of node 1 may be set, and a group address may be set to distinguish it from other groups. In addition, the addresses of group members (node 2, node 3, node 8 to node 10) constituting the group are also set. Each of these addresses may follow a standardized protocol depending on the type of network in which the nodes exist.

Meanwhile, the address of each group member is set together with the distance from the source node to the corresponding group member. Since the node 2 and the node 3 are in the one-hop area from the source node, the distance value is set to 1, and the nodes 8 to the node 10 are in the two-hop area from the source node.

Information about these other nodes may be obtained in a general ad hoc network communication process prior to group communication using OLSR (Unicast Routing Protocol, RFC 3626).

More information on OLSR is available at http://hipercom.inria.fr/olsr.

For example, in a mobile ad hoc network, since nodes are connected by a wireless link without an infrastructure, the network topology changes frequently due to the mobility of nodes constituting the network. Therefore, the nodes belonging to the mobile ad hoc network include TC address (Topology Control message) including their address information, their routing information, and routing information about neighbor nodes in order to understand the status of neighbor nodes and the topology of the entire network. Replace periodically. That is, each node may store and periodically update information about neighbor nodes collected by the TC message.

In addition, group information for identifying a group member belonging to a specific group may be acquired in advance, and as an example, may be obtained through a control message of the OLSR. In this case, the storage format of the obtained group information may be a topology table of OLSR.

5A illustrates a control message of OLSR according to an embodiment of the present invention.

As shown, a group offset indicating a position at which a group address starts in a reserved field of a conventional OLSR control message is set, and a group address for identifying each group is set from a position designated by the group offset.

5B is a diagram illustrating a topology table of OLSR according to an embodiment of the present invention.

As shown, a group address list has been added to the conventional OLSR topology table.

When the initialization packet is generated, the source node broadcasts it, and the nodes receiving the initialization packet reset the distance value included in the initialization packet by decreasing the distance value set by the initialization packet by one.

For example, when the source node (node 1) generates and broadcasts an initialization packet including the information shown in FIG. 4, nodes (nodes 2 to 6) in the 1-hop region are received from node 1. Nodes 2 through 6 then reset so that the distance value set in the received initialization packet is reduced by one, and the content contained in the reset packet is shown in FIG. 6A.

On the other hand, the nodes (nodes 2 to 6) which reset the distance value of the initialization packet determine whether to transmit the initialization packet to their neighbor nodes. This determination may be performed by comparing the distance value reset in the initialization packet with the distance value from itself to each group member.

As a result of comparing the distance values, if the distance between itself and the group members is less than or equal to the distance value reset in the initialization packet, the nodes broadcast the initialization packet. Otherwise, the nodes stop transmitting the initialization packet. This will be described in detail with reference to FIG. 6B.

6B shows the distance value of each group member set in the initialization packet and the distance value from the nodes (nodes 2 to 6) that received the initialization packet of the source node (node 1) to each group member. Each distance value represents a hop number and was calculated based on the nodes shown in FIG. 3.

In the case of node 3, the distance value from node 3 to node 2 and node 10 is larger than the distance value of node 2 and node 10 set in the initialization packet. However, since the distance values to the nodes 8 and 9 are the same as the distance values of the nodes 8 and 9 set in the initialization packet, the node 3 broadcasts the initialization packet to the neighbor nodes. Accordingly, nodes 8 and 9 in the 1-hop region also receive the initialization packet from node 3.

On the other hand, referring to the case of node 4, the distance values from node 4 to node 2, node 3, node 8 and node 9 are all larger than the distance value set in the initialization packet. However, since the distance value to the node 10 is the same as the distance value of the node 10 set in the initialization packet, the node 4 may also transmit the initialization packet to neighboring nodes. Accordingly, node 10 in the 1 hop region also receives an initialization packet from node 4. FIG. Therefore, the initialization packet broadcast from the source node is delivered to all group members.

On the other hand, node 2, node 5 and node 6 stops transmitting the initialization packet because the distance value from itself to other group members is always larger than the distance value set in the initialization packet.

Nodes 8 to 10 that have received the initialization packet over two hops from the source node also decrease the distance value set in the received initialization packet by one. In this case, when the value of the distance value set in the received initialization packet is 0 (for example, the distance value of the node 2 and the node 3 in FIG. 6A), this value may be maintained. Information contained in the initialization packet whose distance value is reset by the nodes 8 to 10 is shown in FIG. 6C. As shown, if the distance values are all set to 0, the nodes stop sending further initialization packets.

On the other hand, the nodes (nodes 3 and 4) determined to transmit the reset packet having the reset distance value store the source node and group address (node 1 and group A address) set in the initialization packet, and the corresponding source node for the group. It becomes a relay for relaying data packets. Therefore, when the same source node that the user stores later transmits a data packet for the same group, nodes that set themselves as relays may forward it to their neighbors.

After broadcasting the initialization packet, the source node actually broadcasts the data packet to be transmitted. Since the source node address and the group address are set in the broadcast data packet, only nodes (nodes 3 and 4) that set themselves as relays during the initialization packet delivery process broadcast the received data packet and, as a result, forward the initialization packet. Data packets can be delivered along the path.

As described above, according to the present invention, since the transmission of data packets to the region 210 in which the group members are not distributed is restricted, the waste of network resources can be reduced.

7 is a block diagram illustrating a network device according to an embodiment of the present invention.

The illustrated network apparatus includes a transceiver 330 for transmitting and receiving a packet through a wireless link, a controller 310 for generating an initialization packet for group communication or retransmission of a received initialization packet, and information about other nodes. It includes a storage unit 320 for storing.

The storage unit 320 stores information and routing information about addresses of other nodes and a distance from the network device to each node. Such information may be obtained in general ad hoc network communication process prior to group communication through OLSR (Optimized Link State Routing Protocol, RFC 3626).

For example, since a mobile ad hoc network has mobile nodes connected by a wireless link without an infrastructure, the network topology changes frequently due to the mobility of nodes constituting the network. Therefore, nodes in the mobile ad hoc network periodically send a TC control message that includes their own address information, their routing information, and routing information of neighbor nodes in order to understand the status of neighbor nodes and the topology of the entire network. Replace with That is, each node may store information about neighbor nodes collected by the TC message in the storage unit 320 and periodically update it.

The storage unit 320 may also store group information for identifying group members belonging to a specific group. Group information may also be obtained in advance, and as an example, may be obtained through a control message of the OLSR. In this case, the storage format of the obtained group information may be a topology table of OLSR. A description of the control message and the topology table according to an embodiment of the present invention has been described above with reference to FIGS. 5A and 5B.

When the network device is a source node, the controller 310 generates an initialization packet to set up a routing path for group communication. In the initialization packet, information on an address, a group address, a group member address of the source node, and a distance from the source node to each group member is set, as described with reference to FIG. 4.

When the initialization packet is broadcast through the transceiver, the controller 310 may actually transmit data packets to be transmitted.

On the other hand, when the network device is a receiving node, when the initialization packet is received through the transceiver 330, the controller 310 decreases each distance value set in the initialization packet by one. Thereafter, the controller 310 determines whether to transmit the initialization packet by comparing the distance value from the network device to each group member, which has been previously obtained and stored in the storage unit 320, with the distance value reset in the initialization packet.

If the distance value of each group member stored in the storage unit 320 is smaller than or equal to the distance value of each group member reset, the controller 310 transmits the initialization packet to neighbor nodes. . At this time, the control unit 310 stores the source node and the group address set in the initialization packet in the storage unit 320, and relays the data packet transmitted by the same source node for the same group.

On the other hand, if all the distance values to each group member stored in the storage unit 320 is greater than the distance value to each group member reset in the initialization packet, the controller 310 stops transmitting the initialization packet. Therefore, in this case, the network device does not relay the data packet of the same source node in the group communication.

8 is a flowchart illustrating a process of transmitting an initialization packet by a source node.

A source node which initially forms a specific group and wants to transmit a data packet to group members of a group to which it belongs, generates an initialization packet to establish a routing path of group communication (S110). In the initialization packet, information on an address, a group address, a group member address of the source node, and a distance from the source node to each group member is set, as described with reference to FIG. 4.

Information set in the initialization packet, such as the address of the group members and the distance from the source node to each group member, may be obtained in advance for general ad hoc communication, not group communication, and the description thereof is as described above. .

When the initialization packet is generated, the source node broadcasts it (S120). Since the group communication routing path is established by the broadcast initialization packet, the source node may then transmit data packets to be transmitted by broadcast (S130 and S140).

9 is a flowchart illustrating a process of delivering an initialization packet of a node that has received an initialization packet.

When the initialization packet as described above is received (S210), the node receiving the same decreases the distance value set in the initialization packet by one (S220). The received initialization packet may be transmitted from a source node or may be forwarded from another node.

Thereafter, each distance value reset in the initialization packet is compared with a distance value from the network device to each group member, which is obtained in advance and stored in the storage 320 (S230). The information about the distance to each group member may be obtained in advance for general ad hoc communication, not group communication, and the description thereof has been described above.

If there is a distance value less than or equal to the distance value of each group member set in the initialization packet among the distance values to each group member stored in the storage unit 320, the receiving node may identify the source node and the group address set in the initialization packet. If the data packet of the same source node is received for the same group in the future, the storage unit stores the storage unit and sets itself as a relay relaying it (S240). In addition, in this case, the initialization packet is broadcast to neighboring nodes (S250).

Therefore, when the same source node stored as the one transmits a data packet for the same group, the receiving node transmits it to its neighboring nodes (S260).

On the other hand, if all distance values to each group member stored in the storage unit 320 are larger than the distance values to each group member set in the initialization packet, the receiving node stops transmitting the initialization packet. Therefore, in this case, the receiving node does not relay the data packets of the same source node in the corresponding group communication.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. You will understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

According to the method and apparatus for establishing a routing path of the present invention as described above, it is possible to reduce waste of network resources in performing group communication in a mobile ad hoc network.

Claims (10)

Generating a group communication initialization packet including a source node address, a group address, an address of group members and a distance value from the source node to each of the group members; And And broadcasting the initialization packet. The method of claim 1, wherein the information included in the initialization packet is obtained by a control message of OLSR. Receiving a group communication initialization packet comprising a source node address, a group address, an address of group members and a distance value from the source node to each of the group members; Resetting each distance value included in the initialization packet to be reduced by one hop; Selectively broadcasting a group communication initialization packet of which the distance value is reset according to a difference between the reset distance value and the distance value from itself to each group member; And After broadcasting the group communication initialization packet, relaying a data packet between the source node and the group members for group communication. The method of claim 3, wherein the information included in the initialization packet is obtained by a control message of an OLSR. 4. The method of claim 3, wherein selectively broadcasting the group communication initialization packet with the distance value reset includes: comparing the reset distance value with a distance value from itself to each group member; And If there is a distance value from the distance value from itself to each group member that is not greater than the distance value from each reset group member as a result of the comparison, broadcasting a group communication initialization packet with the distance value reset; To establish a routing path for group communication. A control unit for generating a group communication initialization packet including a source node address, a group address, an address of group members, and a distance value from the source node to each of the group members; And And a transceiver configured to broadcast the generated initialization packet. The network device of claim 6, wherein the information included in the initialization packet is obtained by a control message of an OLSR. A transceiver for receiving a group communication initialization packet including a source node address, a group address, an address of group members, and a distance value from the source node to each of the group members; And Resetting each distance value included in the initialization packet by one hop, and transmitting and receiving the group communication initialization packet in which the distance value is reset according to a difference between the reset distance value and the distance value from itself to each group member. And a control unit for selectively broadcasting through a unit, and relaying a data packet between the source node and the group members for group communication after the group communication initialization packet is broadcast. The network device of claim 8, wherein the information included in the initialization packet is obtained by a control message of an OLSR. The network of claim 8, wherein the group communication initialization packet having the reset distance value is broadcast when there is a distance value not greater than the distance value to each reset group member among the distance values to each group member. Device.

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