JP2014204437A - Acquisition of downlink routing, maintenance method, and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a node for a multi-hop network.SOLUTION: A transferred or monitored data packet is decoded. A source node, a destination node, a transmission node, a reception node, a type, and a data payload are acquired. When the number of hops from the source node to the destination node is larger than the number of hops from said node to the destination node and a difference between the two is 2, determination is made, on the basis of a data packet transfer table, as to whether or not a data packet was transferred or monitored. When the data packet was not transferred or monitored and the reception node is said node, information about a parent node of the source node is added to the data packet, and the data packet including the parent node information is transferred. When the data packet was not transferred or monitored, an information item corresponding to the source node and its parent node is stored in the data packet transfer table, a transmission mark is set to a prescribed value, and a forgotten time is initialized.

Description

  The present invention relates to the field of communication technology, and more particularly to a method and apparatus for acquiring and maintaining downlink routing in a multi-hop network.

  In order to aggregate data packets at a gateway, the multi-hop network mainly provides uplink routing (from the general node to the gateway). When the gateway controls a node or voluntarily queries a node's data, downlink routing is required. Since the storage space of the general node is limited, the routing of the multi-hop node cannot be maintained, so it is necessary to acquire and maintain the downlink routing on the gateway side.

  The conventional routing algorithm establishes a global routing table in the gateway, thereby obtaining and maintaining downlink routing in the gateway. However, this method requires a method of broadcasting and flooding, so that the load of acquisition and maintenance is large.

  The above description of the technical background is an explanation for making the technical solution of the present invention clear and complete, and is described for the purpose of understanding those skilled in the art. These technical solutions are merely described as the background art portion of the present invention, and are not known by those skilled in the art.

  Embodiments of the present invention mainly provide a downlink routing acquisition and maintenance method and apparatus that effectively acquire and maintain downlink routing on the gateway side and reduce the load on the system.

  In one aspect of an embodiment of the present invention, a node in a multi-hop network decodes a forwarded or monitored data packet, and the data packet source node, destination node, transmission node, reception node, type, and A decoding means for obtaining a data payload, and the number of hops from the source node to the destination node of the data packet is greater than the number of hops from the node to the destination node, and the difference between the two is 2, First determining means for determining whether or not the data packet of the source node has been transferred or monitored based on a data packet transfer table; and if the data packet of the source node has not been transferred or monitored, the first The receiving node of the data packet is not The parent node information of the source node of the data packet is added to the data packet, the transmission means for transferring the data packet including the parent node information, and the data packet of the source node have not been transferred or monitored And the first determination means store information items corresponding to the source node and its parent node in the data packet forwarding table, and set a transmission mark corresponding to the information item to a predetermined value. And a first updating means for initializing a preset forgetting time corresponding to the information item.

  In another aspect of an embodiment of the present invention, a gateway node in a multi-hop network, based on a received data packet including parent node information, a downlink routing table includes an address of the source node of the data packet and its If the determination result of the first determination means and the first determination means is negative to determine whether an information item corresponding to the address of the parent node is stored, one piece of information in the downlink routing table Write the address of the source node of the data packet and the address of its parent node in the item, update the update time corresponding to the information item, or update the update time and the expiration time corresponding to the information item, If the determination result of the determination means is affirmative, the downlink routing table Updating the update time corresponding to the information item in the first update time, or updating the update time corresponding to the information item in the downlink routing table, and resetting the expiration time corresponding to the information item. The downlink routing table includes a plurality of information items, each information item includes a node address, a parent node address, and an update time, or each information item includes a node address, a parent node address A gateway node is provided that includes an address, update time, and expiration time.

  According to the embodiment of the present invention, the system load due to acquisition and maintenance of downlink routing on the gateway side is reduced.

  Certain embodiments of the present invention are disclosed in detail and illustrate the manner in which the principles of the present invention can be employed, as illustrated in the following description and drawings. The embodiment of the present invention is not limited in scope. The embodiments of the present invention include various alterations, modifications, and equivalents within the scope and spirit of the appended claims.

  Features described and / or shown in one embodiment may be used in one or many other embodiments in the same or similar manner, and may be combined with features in other embodiments, Features in other embodiments may be substituted.

  As used herein, the term “inclusive / include” means the presence of a feature, element, step or component, and the presence or absence of one or more other features, elements, steps or components. It does not exclude the addition.

The present invention can be better understood by the following description with reference to the drawings. Elements in the drawings are not drawn to scale, but illustrate the principles of the invention. Corresponding parts in the drawings may be enlarged or reduced to show certain parts of the invention. Elements and features described in one drawing or embodiment of the invention may be combined with elements and features shown in one or many other drawings or embodiments. In the drawings, similar reference numerals may indicate corresponding members in any number of drawings, and may indicate corresponding members used in a plurality of embodiments.
5 is a flowchart of a downlink routing acquisition and maintenance method according to an embodiment of the present invention. It is a figure which shows the frame structure of the data packet which concerns on the Example of this invention. 5 is a flowchart of a method for adding parent node information to a data packet. It is a figure which shows the frame structure of the data packet after adding parent node information to a data packet. It is a figure which shows the structure of the node in the multihop network which concerns on the Example of this invention. 6 is a flowchart of a downlink routing acquisition and maintenance method according to another embodiment of the present invention. 7 is a flowchart of a method for a gateway node to update its downlink routing table in the method shown in FIG. It is a figure which shows the structure of a downlink routing table. It is a figure which shows the frame structure of the changed ACK message. It is a figure which shows the network topology in an example of the established downlink routing. FIG. 6 illustrates a downlink routing inquiry process. It is a figure which shows the structure of the gateway which concerns on the Example of this invention.

  The embodiments of the present invention can be understood from the drawings and the following description. These embodiments are merely exemplary and do not limit the invention.

  To make it easier for those skilled in the art to understand the principles and embodiments of the present invention, the example of the present invention is described by taking an example of an Ad-hoc network. However, the example of the present invention is limited to an Ad-hoc network. For example, the methods and apparatus provided by the embodiments of the present invention may be applied to other multi-hop networks such as sensor networks.

  In the Ad-hoc network, two types of nodes, that is, a source node and a forwarding node are included. The source node periodically or irregularly transmits data whose final destination is the gateway, and the transfer node transfers only the data packet transmitted from the source node without generating the original data. The source node may have a function of transferring data from other source nodes, and in this case, the function is the same as that of the transfer node. Here, when the source node transmits a data packet to the gateway, address information included in the data packet includes GS (Global Source: source node), GD (Global Destination: destination node), and LS (Local Source: transmission node). ) And LD (Local Destination: receiving node).

  In an embodiment of the present invention, it is assumed that uplink routing has already been established in the network, that is, all nodes have acquired the next hop parent node.

<Example 1>
In this embodiment, a method for acquiring and maintaining a downlink routing is provided, and the method is applied to a node having a forwarding function in a multi-hop network, for example, a forwarding node or a source node. FIG. 1 is a flowchart of the method. As shown in FIG. 1, the method includes the following steps.

  Step 101: The node decodes the transferred or monitored data packet, and acquires the source node, destination node, transmission node, reception node, type, and data payload of the data packet.

  Here, as shown in FIG. 2, the frame structure of the data packet includes a source node (GS), a destination node (GD), a transmission node (LS), a reception node (LD), a number (FID), and a type (TYPE). , And a data payload. In addition, since the meaning of each segment is the same as a prior art, the description is abbreviate | omitted here.

  Step 102: The number of hops of the source node (the number of hops from the source node to the destination node) of the data packet is larger than the number of hops of the node itself (the number of hops from the node to the destination node), and the difference in the number of hops between the two In the case of 2, the node determines whether the data packet of the source node has been transferred or monitored based on the data packet transfer table stored therein.

  Here, the data packet transfer table includes several (one or more) information items, and each information item is stored after the node transfers or monitors the data packet. Each information item includes the address of one source node and the address of its parent node.

  Preferably, each information item may further include a transmission mark indicating the update time of the information item. Here, each node divides the operation time into a number of update cycles, and within one update cycle, the node performed an operation of adding parent node information to the data packet, or corresponds to an item in another node When the transmission of the parent node information is monitored, the transmission mark corresponding to this information item is set to a predetermined value, for example 1, and when the next update period is entered, the transmission mark is set to a non-predetermined value, for example 0. Reset it. Further, when the node receives the data packet from the source node, the node needs to determine the transmission mark if the information in the data packet is the same as the information of the stored item. In one update cycle, if the transmission mark is the predetermined value (for example, 1), the process is terminated. If the transmission mark is not the predetermined value (for example, 0), the parent node information is included in the data packet. The transmission mark is changed to the predetermined value. A specific processing process will be described later.

  Preferably, each information item may further include a forgetting time indicating an expiration time of the information item. When creating an information item of the data packet table, the forgetting time of the information item may be initialized and set. When a node receives or monitors a data packet corresponding to an information item (for example, the information in the data packet is the same as the stored item information), the forgetting time corresponding to the information item is reset to the initial value. To do. When the forgetting time corresponding to one information item has reached, the node may determine whether to delete the information item based on its own load.

  Here, since the information item including the address of the source node is stored in the data packet transfer table, when a data packet of a certain source node has been transferred, the data packet transfer table corresponds to the source node. The information item should be stored. For this reason, it is possible to determine whether or not the data packet transmitted from the source node has been transferred by referring to the information item in the data packet transfer table stored on the node side.

  Step 103: When the data packet of the source node has not been transferred or monitored and the receiving node of the data packet is the node, the node adds the parent node information of the source node of the data packet to the data packet. And transfer the data packet including the parent node information.

  In one embodiment, if the node has not forwarded or monitored the data packet of the source node, the node stores information items corresponding to the source node and its parent node in the data packet forwarding table; A transmission mark corresponding to the information item is set to a predetermined value.

  Here, the node has not transferred or monitored the data packet of the source node, and the LD (receiving node) in the data packet is the ID of the node itself, that is, this node is the receiving node of the data packet. If the node needs to transfer the data packet, the node adds the parent node information of the source node in the data packet to the data packet, and transfers the data packet including the parent node information. . In one embodiment, the node needs to further create an information item corresponding to the source node and its parent node in the local data packet forwarding table, where the source node in the information item is the The GS in the data packet, and its parent node is the LS in the data packet. The transmission mark corresponding to the newly created information item may be further set to the predetermined value. Further, the forgetting time corresponding to the newly created information item may be further initialized.

  Here, the node has not transferred or monitored the data packet of the source node, and the LD (receiving node) in the data packet is not the ID of the node itself, that is, this node is not the receiving node of the data packet. If the node does not need to transfer the data packet and simply monitors the data packet, the node only needs to add the parent node information of the source node in the data packet to the data packet. Similarly, the source node in the information item is a GS in the data packet, and its parent node is an LS in the data packet. Similarly, the transmission mark corresponding to the newly created information item may be set to the predetermined value. Further, the forgetting time corresponding to the newly created information item may be initialized at the same time.

  This node may add the parent node information of the source node in the data packet to the data packet by the method shown in FIG. As shown in FIG. 3, the method includes the following steps.

  Step 301: Extract a transmission node from the data packet.

  Here, as described in step 102, since this node is a two-hop node from the source node, the transmission node (LS) in the data packet is the parent node of the source node.

  Step 302: Add a transmission node of the data packet to the data payload of the data packet.

  Here, by adding the transmission node of the source node to the data payload of the data packet, the gateway and its parent node information can be acquired so as to determine the downlink routing. Details will be described in the following examples.

  The frame structure of the changed data packet is shown in FIG. 4, and the data payload (DATA Payload) of the data packet includes not only the original data content (DATA) but also parent node information (Parent ID). Yes. In the example shown in FIG. 4, the parent node information is added to the head portion of the data payload, but the present embodiment is not limited to this.

  Step 303: The type of the data packet is changed to a data packet including parent node information of the source node.

  Here, by changing the type of the data packet (for example, the TPYE segment shown in FIG. 4), the gateway can determine the type of the data packet. As a result of determining the type of the data packet, when the data packet is a data packet including parent node information, information on the source node and its parent node may be extracted and added to the downlink routing table. Details will be described in the following examples.

  In order to better understand the method of this embodiment, the method is described in the following example.

  For example, in the example in which the source node A transmits a data packet to the node C via the node B, in the data packet received by the node C, GS is the node A, LS is the node B, and LD is the node C. Node C queries the local data packet transfer table and has not transferred or monitored the data packet from node A. That is, the data packet transfer table includes an information item in which the source node is node A. If not, the node C extracts the LS, that is, the address of the node B from the data packet according to the method of this embodiment, adds it to the data payload of the data packet, and sets the type of the data packet to the data including the parent node information. Change to packet and transfer the data packet. Further, the information item of node A and its parent node B may be added to the data packet transfer table, the transfer mark corresponding to the information item is set to a predetermined value, and the forgetting time corresponding to the information item may be initialized. .

  As another aspect of this embodiment, in the same example, when node D monitors the data packet (GS is node A, LS is node B, and LD is node C), node D When the data packet transfer table is inquired and the data packet from the node A has not been transferred or monitored, that is, when the data packet transfer table does not include an information item whose source node is the node A, According to the method, since node D is not the receiving node of the data packet, node D only needs to create information items of node A and its parent node B corresponding to the data packet in the data packet forwarding table. Alternatively, the transfer mark corresponding to the information item may be set to a predetermined value, and the forgetting time corresponding to the information item may be initialized.

  According to the processing of steps 101 to 103, the node transfers the data packet including the parent node information, so that the gateway node acquires the source node and its parent node and stores them in its downlink routing table. Can do. The gateway node can determine the downlink routing of an arbitrary node by obtaining information of all the source nodes and their parent nodes in the multi-hop network by this method. Downlink routing can be acquired and maintained on the gateway node side, and the load on the system can be reduced accordingly. The processing on the network side will be described in the following example.

  In one example of this embodiment, if it is determined in step 102 that the node has transferred or monitored the data packet of the source node, the method may further include the following steps.

  Step 104: The node determines whether or not the information item corresponding to the source node and its parent node is stored based on the stored data packet forwarding table.

  Step 105: If the information item corresponding to the source node and its parent node has not been stored and the receiving node of the data packet is the node, the node adds the data packet to the source node of the data packet. The parent node information is added, and the data packet including the parent node information is transferred.

  Similar to step 103, if the information item corresponding to the source node and its parent node has never been stored, the node corresponds to the source node and its parent node in the data packet forwarding table. Information items may be further stored. Preferably, a transmission mark corresponding to the information item may be set to a predetermined value, and a preset forgetting time corresponding to the information item may be initialized.

  In this example, if the node has transferred or monitored the data packet of the source node and does not store information items corresponding to the source node and its parent node, the node is the same as above. As described above, the following processing may be performed. That is, when the LD of the data packet is this node, the parent node information of the source node in the data packet is added to the data packet, the data packet including the parent node information is transferred, and the source packet is transferred to the data packet transfer table. Information items corresponding to the node and its parent node may be created. Preferably, the transmission mark corresponding to the information item may be set to a predetermined value, and the forgetting time corresponding to the information item may be initialized. On the other hand, when the LD of the data packet is not this node, it is only necessary to add a new information item to the data packet. Preferably, the transmission mark corresponding to the information item may be set to a predetermined value. Preferably, the forgetting time corresponding to the information item may be initialized at the same time.

  In this example, this node may add the parent node information of the source node in the data packet to the data packet by the method shown in FIG. Since it is the same as the above, its description is omitted.

  In order to better understand the method of this embodiment, the method is described in the following example.

  For example, in the example in which the source node A transmits a data packet to the node C via the node B, in the data packet received by the node C, GS is the node A, LS is the node B, and LD is the node C. Node C queries the local data packet forwarding table and includes information items for node A and its parent node E, but does not include information items for node A and its parent node B, ie from source node A. Although the data packet has been transferred or monitored, since the data packet was transferred via the node E, not the node B, the stored information item is the node A and its parent node E, and is received this time. It was discovered that the information items corresponding to the source node A and the parent node B of the data packet are not stored. According to the method of this embodiment, the node C extracts the LS, that is, the address of the node B from the data packet, adds it to the data payload of the data packet, and changes the type of the data packet to the data packet including the parent node information. Then, the data packet is transferred. Further, the information item of node A and its parent node B may be added to the data packet transfer table, the transfer mark corresponding to the information item is set to a predetermined value, and the forgetting time corresponding to the information item may be initialized. .

  As another aspect of the present embodiment, in the same example, when the node D monitors the data packet (GS is the node A, LS is the node B, and LD is the node C), the data packet forwarding table of the node D has the node When the information items of A and its parent node E are stored and the information items of node A and its parent node B of the data packet are not stored, node D is not the receiving node of the data packet, so node D It is only necessary to create information items of the node A and its parent node B corresponding to the data packet in the data packet forwarding table. Alternatively, the transfer mark corresponding to the information item may be set to a predetermined value, and the forgetting time corresponding to the information item may be initialized.

  According to the processing of steps 101, 102, 104, and 105, the node transfers the data packet including the parent node information, so that the gateway node acquires the source node and its parent node, and its own downlink routing table. Can be memorized. The gateway node can determine the downlink routing of an arbitrary node by obtaining information of all the source nodes and their parent nodes in the multi-hop network by this method. Downlink routing can be acquired and maintained on the gateway node side, and the load on the system can be reduced accordingly. The processing on the network side will be described in the following example.

  In one example of this embodiment, when it is determined in step 104 that information items corresponding to the source node and its parent node are stored, the method may further include the following steps.

  Step 106: It is determined whether or not the transmission mark corresponding to the information item has a predetermined value in a preset update cycle.

  Step 107: When it is determined that the transmission mark corresponding to the information item is not a predetermined value in the preset update cycle and the receiving node of the data packet is the node, the data packet includes The parent node information of the source node is added, and the data packet including the parent node information is transferred.

  Here, if the transmission mark corresponding to the information item is not a predetermined value in the preset update cycle, the transmission mark corresponding to the information item is changed to the predetermined value, and preferably corresponds to the information item. The forgotten time set in advance may be reset to the initial value.

  In addition, when the transmission mark corresponding to the information item is a predetermined value in the preset update cycle, the node may end the process.

  In this embodiment, if this node has transferred or monitored a data packet from the source node and stores information items corresponding to the source node and its parent node, it corresponds to the information item. When the transmission mark is still a predetermined value (for example, 1), it indicates that the information item has not passed the update cycle, and no processing is performed, or the forgetting time corresponding to the information item is reset to the initial value. Also good. On the other hand, when the transmission mark corresponding to the information item is a non-predetermined value (for example, 0), it indicates that the information item has already passed the update cycle, and when the LD of the data packet is the present node, the data packet The parent node information is added, the data packet including the parent node information is transferred, and the information item is processed again, so that the transmission mark corresponding to the information item is changed to a predetermined value again, Preferably, the forgetting time corresponding to the information item may be reset to an initial value. On the other hand, when the LD of the data is not this node, that is, when this node simply monitors the data packet, this node only needs to change the transmission mark of the information item in the data packet forwarding table to the predetermined value. Preferably, the forgetting time corresponding to the information item may be reset to an initial value.

  In this example, this node may add the parent node information of the source node in the data packet to the data packet by the method shown in FIG. Since it is the same as the above, its description is omitted.

  In order to better understand the method of this embodiment, the method is described in the following example.

  For example, in the example in which the source node A transmits a data packet to the node C via the node B, in the data packet received by the node C, GS is the node A, LS is the node B, and LD is the node C. Node C queries the local data packet forwarding table, has found information items for node A and its parent node B, ie has forwarded or monitored the data packet of source node A, and the data Information items corresponding to the source node A and the parent node B of the packet are stored. In this case, according to the method of the present embodiment, the node C inquires whether or not the transmission mark corresponding to the information item is a predetermined value in the update period, and when it is the initial value, it has just transferred the data packet. Node C does not perform any processing. On the other hand, when it is not the initial value, it indicates that the information item has passed the update cycle, and since node C is the receiving node of the data packet, node C extracts the LS, that is, the address of node B from the data packet Are added to the data payload of the data packet, the type of the data packet is changed to a data packet including parent node information, and the data packet is transferred. Further, the information item of node A and its parent node B may be added to the data packet transfer table, the transfer mark corresponding to the information item is set to a predetermined value, and the forgetting time corresponding to the information item may be initialized. .

  As another aspect of the present embodiment, in the same example, when the node D monitors the data packet (GS is the node A, LS is the node B, and LD is the node C), the data packet forwarding table of the node D has the node When the information item of A and its parent node B is stored, since node D is not the receiving node of the data packet, node D will correspond to node A and its parent node corresponding to the data packet in the data packet forwarding table It is only necessary to create the information item B. Alternatively, the transfer mark corresponding to the information item may be set to a predetermined value, and the forgetting time corresponding to the information item may be initialized.

  According to the processing of steps 101, 102, 104, 106, and 107, the node forwards the data packet including the parent node information, so that the gateway node acquires the source node and its parent node, and its own downlink It can be stored in a routing table. The gateway node can determine the downlink routing of an arbitrary node by obtaining information of all the source nodes and their parent nodes in the multi-hop network by this method. Downlink routing can be acquired and maintained on the gateway node side, and the load on the system can be reduced accordingly. The processing on the network side will be described in the following example.

  In this embodiment, when the above-mentioned node is a transfer node that does not generate the original data packet and transfers only the data packet of the other node, the node transfers the data packet of the other node for the first time. After that, a message with an empty data payload may be voluntarily transmitted to the gateway at an update cycle. As a result, the node having the data transfer function that has received this message processes it in the same manner as the structure of the data packet transmitted from the source node, and the gateway node can acquire the parent node information of the node.

  In this embodiment, after transferring a data packet including parent node information from another node, this node temporarily stores the data packet including the parent node information in order to ensure transmission reliability. When the transmission of the data packet including the parent node information to the next hop node is successful (transmission and reception is successful), the node deletes the data packet including the parent node information and the data packet including the parent node information. If transmission to the next hop node fails (transmission fails), the node may re-add the data packet to the transmission order and retransmit the data packet. The additional position may be selected according to the actual situation, and may be added at the end of the transmission order, for example.

  In this embodiment, in order to further reduce the load on the system, when the node is a one-hop node in the multi-hop network, the operation (data) of the first embodiment is performed when the node transfers a data packet to the gateway. The data packet may be directly transferred according to the conventional method without executing parent node information to the packet and adding an item to the data packet transfer table. At this time, the gateway can query all the 1-hop nodes from its own adjacent node table, and acquire the parent node information of the 1-hop node, that is, the gateway itself.

  In this embodiment, in order to further reduce the load on the system, when a handshake (Hello) method or an acknowledgment (ACK) method is used, when the node is a one-hop node in the multihop network, the data packet is transferred. At this time, the LS information in the data packet may be deleted. That is, when the 1-hop node transfers the data packet to the gateway, the LS information of the data packet is deleted based on the conventional method, and the gateway transmits the hello packet or ACK between the 1-hop node and the 2-hop node. By monitoring the packet, it is possible to acquire parent node (1-hop node) information corresponding to the 2-hop node. Details are described in detail in Example 3.

  According to the method of this embodiment, a node having a transfer function in a multi-hop network transfers a data packet including parent node information to the next hop node, so that the gateway can acquire information on each node and its parent node. By establishing a downlink routing table based on the information, it is possible to determine downlink routing to an arbitrary node. Downlink routing can be acquired and maintained on the gateway node side, and the load on the system can be reduced accordingly.

  The embodiment of the present invention further provides a node in a multi-hop network and, as described in the second embodiment below, is similar to the problem solving principle of the node and the method of the first embodiment. Reference can be made to the implementation of the method of Example 1, and the description of overlapping parts is omitted here.

<Example 2>
Embodiments of the present invention further provide nodes in a multi-hop network. FIG. 5 is a diagram showing the configuration of the node. As illustrated in FIG. 5, the node includes a decoding unit 51, a first determination unit 52, and a transmission unit 53.

  The decoding unit 51 decodes the transferred or monitored data packet, and acquires the source node, destination node, transmission node, reception node, type, and data payload of the data packet.

  The first determination unit 52 has a hop count of the source node (the hop count from the source node to the destination node) of the data packet larger than a hop count of the node (the hop count from the node to the destination node), and If the difference between the two is 2, whether or not the data packet of the source node has been transferred or monitored is determined based on the data packet transfer table of the node.

  When the first determination unit 52 determines that the data packet of the source node has not been transferred or monitored, the transmission unit 53 transmits the data packet to the data packet when the reception node of the data packet is the node. The parent node information of the source node of the data packet is added, and the data packet including the parent node information is transferred.

  In one example, the node may further include a first update unit 54.

  When the first determination unit 52 determines that the data packet of the source node has not been transferred or monitored, the first update unit 54 corresponds to the source node and its parent node in the data packet transfer table. The information item to be stored is stored, and the transmission mark corresponding to the information item is set to a predetermined value.

  In one example, the node may further include a second determination unit 55.

  When the first determination unit 52 determines that the data packet of the source node has been transferred or monitored, the second determination unit 55 determines the source node and its source based on the data packet transfer table of the node. It is determined whether or not the information item corresponding to the parent node is stored.

  When the second determination unit 55 determines that the information item corresponding to the source node and its parent node has not been stored, the transmission unit 53, when the reception node of the data packet is the node, The parent node information of the source node of the data packet is added to the data packet, and the data packet including the parent node information is transferred.

  In this example, the node may further include a second update unit 56.

  If the second determining unit 55 determines that the information item corresponding to the source node and its parent node has not been stored, the second updating unit 56 stores the source node and the source node in the data packet forwarding table. The information item corresponding to the parent node is stored, and the transmission mark corresponding to the information item is set to a predetermined value.

  In one example, the node may further include a third determination unit 57.

  When the second determination unit 55 determines that the information item corresponding to the source node and its parent node has been stored, the third determination unit 57 stores the information item in the preset update cycle. It is determined whether or not the corresponding transmission mark is a predetermined value.

  When the determination result of the third determination unit 57 is negative, the transmission unit 53 adds the parent node information of the source node of the data packet to the data packet when the reception node of the data packet is the node, Transfer data packets containing parent node information.

  In this example, the node may further include a third update unit 58.

  When the determination result of the third determination unit 57 is negative, the third update unit 58 changes the transmission mark corresponding to the information item to the predetermined value.

  In the above example, the transmission unit 53 may include the following modules.

  The extraction module 531 extracts a transmission node from the data packet.

  The addition module 532 adds the transmission node of the data packet to the data payload of the data packet.

  The change module 533 changes the type of the data packet to a data packet including parent node information of the source node.

  The transmission module 534 transmits a data packet including parent node information.

  In the above example, the first updating unit 54 may initialize a preset forgetting time corresponding to the information item after setting the transmission mark corresponding to the information item to a predetermined value.

  In the above example, the second updating unit 56 may initialize a preset forgetting time corresponding to the information item after setting the transmission mark corresponding to the information item to a predetermined value.

  In the above example, the third updating unit 58 changes the transmission mark corresponding to the information item to the predetermined value, and then resets the preset forgetting time corresponding to the information item to the initial value. Also good.

  In this embodiment, when the node is a transfer node, the transmission unit 53 transmits a data packet with an empty data payload to the gateway at a predetermined update cycle after first transferring the data packet of another node. May be.

  In one example, the node may further include a temporary storage unit 59.

  The temporary storage unit 59 temporarily stores the data packet including the parent node information after the transmission unit 53 transfers the data packet including the parent node information.

  The transmission unit 53 deletes the data packet including the parent node information stored in the temporary storage unit 59 when the transmission and reception of the data packet including the parent node information is successful, and when the transmission is failed, the temporary storage unit 59 The data packet including the parent node information stored in is retransmitted. For example, the data packet including the parent node information is added to the transmission order and transmitted.

  Since the function of each component of the node according to the present embodiment is the same as each step of the method according to the first embodiment, description of the contents thereof is omitted here.

  The node of this embodiment transfers a data packet including parent node information to the next hop node, so that the gateway can acquire information on each node and its parent node, and establish a downlink routing table based on the information. Thus, the downlink routing to an arbitrary node can be determined. Downlink routing can be acquired and maintained on the gateway node side, and the load on the system can be reduced accordingly.

<Example 3>
The embodiment of the present invention further provides a method for acquiring and maintaining a downlink routing applied to a gateway in a multi-hop network. FIG. 6 is a flowchart of the method. As shown in FIG. 6, the method includes the following steps.

  Step 601: The gateway updates a previously stored downlink routing table based on the received data packet including the parent node information.

  Here, the downlink routing table includes a plurality of information items, and each information item includes a node address, a parent node address, and an update time, or each information item includes a node address and a parent node address. , Renewal time, and expiration time.

  In one example of step 601, the gateway node may update the downlink routing table according to the method shown in FIG. As shown in FIG. 7, the method includes the following steps.

  Step 701: Based on the downlink routing table, it is determined whether information items corresponding to the address of the source node of the data packet and the address of its parent node are stored.

  Step 702: If the information item corresponding to the address of the source node of the data packet and the address of its parent node is not stored, the gateway node sets the source of the data packet in one information item of the downlink routing table. The address of the node and the address of its parent node are written, the update time corresponding to the information item is updated, or the update time and the expiration time corresponding to the information item are updated.

  Step 703: If the information item corresponding to the address of the source node of the data packet and the address of its parent node is stored, the gateway node updates the update time corresponding to the information item in the downlink routing table Alternatively, the update time corresponding to the information item in the downlink routing table is updated, and the expiration time corresponding to the information item is reset.

  In this embodiment, when the gateway receives a data packet whose type includes parent node information, the gateway stores the node ID (GS) and parent node ID (Parent) included in the data packet in the downlink routing table. The structure of the downlink routing table is shown in FIG. Here, the node ID may be a source node ID that generates source data, may not be a source data packet, and may be a transfer (Relay) node that transfers only data packets of other nodes, As described in the first embodiment, the forwarding node transmits a message with an empty data payload to the gateway, and GS in the message is the ID of the forwarding node.

  As shown in FIG. 8, in the downlink routing table, the storage content of the first column is the node ID, the storage content of the second column is the corresponding parent node ID, and the update time of the item in the third column The fourth column is optional and may be the expiration time of the information item.

  When the gateway receives a data packet containing an item, when the same item is already stored in the gateway, the gateway may update the update time of the item and further reset the expiration time of the item. If the expiry time of the item has not been reached, the gateway chooses to delete or continue to store this item based on factors such as the number of parent nodes of the node, memory usage, etc.

  According to the method of this embodiment, when a gateway queries the downlink routing of a node, the gateway reverses the completed route, that is, the node's uplink route, according to the reverse order from the node to the gateway. Inquired downlink routes. Here, when one or more parent nodes are stored in the downlink routing table, one of them is selected as the parent node of the downlink routing, for example, the node that forwards the data packet as the last parent node, that is, Select the node whose update time is closest to the current time.

  In one example of this embodiment, in order to further reduce the load on the system, the 1-hop node to the gateway does not aggregate the parent node information to the gateway, that is, does not forward the data packet to the gateway according to the method of the first embodiment. The data packet may be directly transferred according to the conventional method, that is, the parent node information may not be added to the data packet. At this time, the gateway may query its own adjacent node table, query all 1-hop nodes, and acquire the parent node information. That is, in this example, the gateway node queries its neighbor node table to determine the parent node information of the 1 hop node in the multi-hop network, and the 1 hop node is included in one information item of the downlink routing table. And the address of the parent node (that is, the gateway itself) are updated, the update time corresponding to the information item is updated, or the update time and the expiration time corresponding to the information item are updated.

  In another example of this embodiment, in order to further reduce the load on the system, if the 2-hop node to the gateway has a handshake (Hello) method or an acknowledgment (ACK) method, the 1-hop node transfers the data packet. In doing so, the LS information of the data packet may be deleted. The gateway acquires the parent node information of the 2-hop node by monitoring the hello packet or the ACK packet between the 1-hop node and the 2-hop node. At this time, the gateway writes the address of the 2-hop node and the address of its parent node in one information item of the downlink routing table, updates the update time corresponding to the information item, or adds the information item to the information item. Update the corresponding update time and expiration time. Here, the HELLO packet or the ACK packet includes information on the transmission node (1 hop information) and information on the reception node (2 hop information), and the information on the transmission node is parent node information of the 2 hop node. .

  In this example, when the handshake method is used, the inter-node handshake Hello packet has child node information of the transmitting node, and when the 1-hop node transmits the Hello packet to the 2-hop node, the gateway The Hello packet can be monitored, and information on the 1-hop node (parent node) corresponding to the 2-hop node (child node) is acquired and stored in the downlink routing table shown in FIG.

  In this example, when the ACK method is used, the 2-hop node to the gateway does not transmit parent node information to the gateway. The 2-hop node to the gateway needs to transfer the data packet through the 1-hop node to the gateway. When the data packet is successfully received by the 1-hop node to the gateway, an ACK message is returned to the 2-hop node to the gateway. By monitoring these ACK messages, the gateway acquires the routing information of the 2-hop node (child node) and the 1-hop node (parent node), and can add the parent node to the corresponding position in the downlink routing table.

  In the above two examples, different protocols have different ACK message configurations, but both are simple. In order to implement the method according to the embodiment of the present invention, the ACK message may include an ID of a 1-hop node (ACK message transmission side) and an ID of a 2-hop node (ACK message reception side). Taking the IEEE 802.11 protocol as an example, the frame structure of the modified ACK message is shown in FIG. Here, the receiving node ID can be copied from the data frame that needs to be confirmed, that is, the source node ID in the data frame, and the transmitting node ID is the ID of the node itself.

  In order to clarify the method of this embodiment, the method of this embodiment will be described with reference to the following drawings and specific examples.

  FIG. 10 shows a network topology, and FIG. 11 shows a downlink routing inquiry process. In the network topology shown in FIG. 10, the downlink routing table shown in FIG. 11 is established. When the gateway queries the downlink routing of node 8, it first queries node 7 that is the parent node of node 8 from the downlink routing, and then queries node 3 that is the parent node of node 7. This process is repeated until the gateway itself, which is the parent node of the node, is queried. Arranging all the nodes found by querying in reverse order, the gateway obtained the complete downlink routing to node 8, ie 0 → 1 → 3 → 7 → 8.

  According to the method of this embodiment, the gateway can determine the downlink routing to an arbitrary node by establishing and updating the downlink routing table based on the data packet including the parent node information. Downlink routing can be acquired and maintained on the gateway node side, and the load on the system can be reduced accordingly.

  The embodiment of the present invention further provides a gateway node in a multi-hop network, and is similar to the problem solving principle of the node and the method of Embodiment 3 as described in Embodiment 4 below. Regarding the implementation, reference can be made to the implementation of the method of Example 3, and the description of the overlapping parts is omitted here.

<Example 4>
Embodiments of the present invention further provide a gateway in a multi-hop network. FIG. 12 is a diagram showing the configuration of the gateway node. As illustrated in FIG. 12, the gateway node includes a first determination unit 121 and a first update unit 122.

  Based on the received data packet including the parent node information, the first determination unit 121 stores an address of the source node of the data packet and an information item corresponding to the address of the parent node in the downlink routing table. Determine whether or not.

  When the determination result of the first determination unit 121 is negative, the first update unit 122 writes the address of the source node of the data packet and the address of its parent node in one information item of the downlink routing table, When the update time corresponding to the information item is updated, or the update time and the expiration time corresponding to the information item are updated, and the determination result of the first determination unit 121 is affirmative, the information in the downlink routing table The update time corresponding to the item is updated, or the update time corresponding to the information item in the downlink routing table is updated, and the expiration time corresponding to the information item is reset.

  Here, the downlink routing table includes a plurality of information items, and each information item includes a node address, a parent node address, and an update time. Alternatively, each information item includes a node address and a parent node address. Includes address, update time, and expiration time.

  In one example, the gateway node further includes a second determination unit 123 and a second update unit 124.

  The second determination unit 123 determines whether or not the expiration time of each information item in the downlink routing table has been reached.

  If the determination result of the second determination unit 123 is affirmative, the second update unit 124 deletes the information item that has reached the expiration time or reaches the expiration time based on a predetermined rule. Select whether to keep memorizing information items.

  In one example, the gateway node further includes a query unit 125.

  The query unit 125 queries the adjacent node table to determine parent node information of the 1-hop node in the multi-hop network.

  The first updating unit 121 writes the address of the one-hop node and the address of its parent node in one information item of the downlink routing table, updates the update time corresponding to the information item, or the information item Update the update time and expiration time corresponding to.

  In one example, the gateway node further includes an acquisition unit 126.

  The acquisition unit 126 acquires the parent node information of the 2-hop node by monitoring a HELLO packet or an ACK packet transmitted from the 1-hop node of the multi-hop network to the 2-hop node.

  The first updating unit 121 writes the address of the 2-hop node and the address of its parent node in one information item of the downlink routing table, updates the update time corresponding to the information item, or the information item Update the update time and expiration time corresponding to. Here, the HELLO packet or the ACK packet includes information on a transmission node and information on a reception node, the transmission node is the one-hop node, the reception node is the two-hop node, and The information is parent node information of the 2-hop node.

  The gateway node of this embodiment can determine the downlink routing to an arbitrary node by establishing and updating the downlink routing table based on the data packet including the parent node information. Downlink routing can be acquired and maintained on the gateway node side, and the load on the system can be reduced accordingly.

  Embodiments of the present invention further provide a communication network including one or more nodes described in Example 2 and gateway nodes described in Example 4. Since the contents are the same as described above, the description thereof is omitted here.

  An embodiment of the present invention is a computer-readable program that causes a computer to execute the downlink routing acquisition and maintenance method described in the first or third embodiment in the terminal device when the program is executed in the terminal device. Further providing.

  Embodiments of the present invention further provide a recording medium for recording a computer-readable program for causing a computer to execute the downlink routing acquisition and maintenance method described in Embodiment 1 or Embodiment 3 in a terminal device. To do.

  As described above, preferred embodiments of the present invention have been described. Since many features and advantages of these embodiments are expressly set forth in the detailed description, the appended claims are intended to cover all these features and within the true spirit and scope of these embodiments. It covers the benefits. Further, since many modifications and changes can be easily conceived by those skilled in the art, the embodiments of the present invention are not limited to the specific configurations and operations illustrated or described, and all the embodiments within the scope thereof are not limited. Appropriate modifications and equivalents can be covered.

  Each part of the present invention may be realized by hardware, software, firmware, or a combination thereof. In the embodiments described above, the multiple steps or methods may be implemented by executing software or firmware that is stored in memory and executed by the system with appropriate instructions. For example, when implemented by hardware, as in the other embodiments, a discrete logic circuit of a logic gate circuit having a logic function for a data signal, a dedicated integrated circuit for appropriately combining logic gate circuits, and programmable It may be realized by any one or a combination of the following known techniques such as a gate array (PGA) and a field programmable gate array (FPGA).

  Moreover, the following additional remarks are disclosed regarding the embodiment including each of the above-described examples.

(Appendix 1)
A method for acquiring and maintaining a downlink routing applied to a node having a data transfer function in a multi-hop network,
Decoding the transferred or monitored data packet and obtaining a source node, a destination node, a transmitting node, a receiving node, a type, and a data payload of the data packet;
The number of hops of the source node of the data packet (the number of hops from the source node to the destination node) is greater than the number of hops of the node itself (the number of hops from the node to the destination node), and the difference between the two is 2 Determining whether or not the data packet of the source node has been forwarded based on the data packet forwarding table of the node;
When the data packet of the source node has never been transferred, when the receiving node of the data packet is the node, parent node information of the source node of the data packet is added to the data packet, and includes parent node information Forwarding the data packet.

(Appendix 2)
When the data packet of the source node has not been transferred, the information item corresponding to the source node and its parent node is stored in the data packet transfer table, and the transmission mark corresponding to the information item is set to a predetermined value. The method of claim 1, further comprising:

(Appendix 3)
If the data packet of the source node has been transferred, determining whether or not the information item corresponding to the source node and its parent node is stored based on the data packet transfer table of the node;
When the information item corresponding to the source node and its parent node has not been stored, when the receiving node of the data packet is the node, the parent node information of the source node of the data packet is added to the data packet. The method according to claim 1, further comprising: transferring a data packet including parent node information.

(Appendix 4)
If the information item corresponding to the source node and its parent node has never been stored, the information item corresponding to the source node and its parent node is stored in the data packet forwarding table, and the transmission corresponding to the information item is performed. The method according to claim 3, further comprising the step of setting the mark to a predetermined value.

(Appendix 5)
If the information item corresponding to the source node and its parent node has been stored, determining whether or not the transmission mark corresponding to the information item is a predetermined value in a preset update cycle;
When a transmission mark corresponding to the information item is not a predetermined value in a preset update cycle, when the receiving node of the data packet is the node, the parent node information of the source node of the data packet is added to the data packet. And transferring the data packet including the parent node information.

(Appendix 6)
The method according to claim 5, further comprising the step of changing the transmission mark corresponding to the information item to the predetermined value when the transmission mark corresponding to the information item is not a predetermined value in a preset update period.

(Appendix 7)
Adding parent node information of a source node of the data packet to the data packet;
Extracting a sending node from the data packet;
Adding a sending node of the data packet to the data payload of the data packet;
The method according to any one of appendices 1 to 6, further comprising: changing a type of the data packet to a data packet including parent node information of a source node.

(Appendix 8)
The method according to claim 2 or 4, further comprising: initializing a preset forgetting time corresponding to the information item after changing a transmission mark corresponding to the information item to the predetermined value.

(Appendix 9)
The method according to claim 6, further comprising the step of resetting a preset forgetting time corresponding to the information item to an initial value after changing a transmission mark corresponding to the information item to the predetermined value.

(Appendix 10)
If the node is a relay node, the method further includes a step of transmitting a message with an empty data payload to the gateway at a predetermined update period after first transmitting a data packet of another node. the method of.

(Appendix 11)
After the data packet including the parent node information is transferred, the data packet including the parent node information is temporarily stored, and when the transmission and reception of the data packet including the parent node information is successful, the node The method according to claim 1, further comprising the step of: deleting a data packet that includes parent node information, and retransmitting the data packet that includes parent node information if the data packet fails.

(Appendix 12)
A method for acquiring and maintaining a downlink routing applied to a gateway node in a multi-hop network,
The gateway node includes updating a pre-stored downlink routing table based on a received data packet including parent node information;
The downlink routing table includes a plurality of information items, each information item includes a node address, a parent node address, and an update time, or each information item includes a node address, a parent node address, an update time, and A method, including an expiration time.

(Appendix 13)
The gateway node updates the pre-stored downlink routing table based on the data packet including the received parent node information.
When the information item corresponding to the address of the source node of the data packet and the address of its parent node is not stored in the downlink routing table, the gateway node stores the data item in one information item of the downlink routing table. Appendix 12 which includes writing the address of the source node of the packet and the address of its parent node, updating the update time corresponding to the information item, or updating the update time and expiration time corresponding to the information item. The method described.

(Appendix 14)
The gateway node updates the pre-stored downlink routing table based on the data packet including the received parent node information.
When information items corresponding to the address of the source node of the data packet and the address of its parent node are stored in the downlink routing table, the update time corresponding to the information item in the downlink routing table is updated, The method according to claim 12, further comprising: updating an update time corresponding to the information item in the downlink routing table and resetting an expiration time corresponding to the information item.

(Appendix 15)
When the expiration time of one information item of the downlink routing table has been reached, the gateway node selects whether to delete the information item or continue to store the information item based on a predetermined rule The method of claim 12, further comprising the step of:

(Appendix 16)
The gateway node queries an adjacent node table to determine parent node information of a one-hop node in the multi-hop network, and an address of the one-hop node and its parent node are included in one information item of the downlink routing table. The method according to claim 12, further comprising the step of: updating the update time corresponding to the information item, or updating the update time and the expiration time corresponding to the information item.

(Appendix 17)
The gateway node obtains parent node information of the 2-hop node by monitoring a HELLO packet or an ACK packet transmitted from the 1-hop node of the multi-hop network to the 2-hop node;
The gateway node writes the address of the 2-hop node and the address of its parent node in one information item of the downlink routing table, updates the update time corresponding to the information item, or corresponds to the information item Updating the renewal time and expiration time;
The HELLO packet or the ACK packet includes transmission node information and reception node information, the transmission node is the 1-hop node, the reception node is the 2-hop node, and the transmission node information is the The method according to appendix 12, which is parent node information of a 2-hop node.

Claims (10)

A node in a multi-hop network,
Decoding means for decoding the transferred or monitored data packet and obtaining a source node, a destination node, a transmission node, a reception node, a type, and a data payload of the data packet;
When the number of hops from the source node to the destination node of the data packet is larger than the number of hops from the node to the destination node, and the difference between the two is 2, based on the data packet forwarding table of the node, the source First determining means for determining whether the data packet of the node has been transferred or monitored;
When it is determined by the first determining means that the data packet of the source node has not been transferred or monitored, the source node of the data packet is included in the data packet when the receiving node of the data packet is the node Transmitting means for adding the parent node information and transferring a data packet including the parent node information;
If it is determined by the first determining means that the data packet of the source node has not been transferred or monitored, the data packet transfer table stores information items corresponding to the source node and its parent node; And a first updating means for setting a transmission mark corresponding to the information item to a predetermined value and initializing a preset forgetting time corresponding to the information item. A second determining unit; and a second updating unit,
The second determining means, when the first determining means determines that the data packet of the source node has been transferred or monitored, based on the data packet transfer table of the node, and Determine whether the information item corresponding to the parent node is stored,
When the second determining unit determines that the information item corresponding to the source node and its parent node has not been stored, the transmitting unit is configured such that when the receiving node of the data packet is the node, Adding parent node information of the source node of the data packet to the data packet, transferring the data packet including the parent node information,
When the second determining unit determines that the second determining unit determines that the information item corresponding to the source node and its parent node has not been stored, the second updating unit stores the source node and the source node in the data packet forwarding table. Storing an information item corresponding to the parent node, setting a transmission mark corresponding to the information item to a predetermined value, and initializing a preset forgetting time corresponding to the information item;
The node according to claim 1. And further comprising third determining means and third updating means,
When the second determining unit determines that the information item corresponding to the source node and its parent node has been stored, the third determining unit stores the information item in the preset update cycle. Determine whether the corresponding transmission mark is a predetermined value,
When the determination result of the third determining means is negative, the transmitting means adds parent node information of the source node of the data packet to the data packet when the receiving node of the data packet is the node, Forward data packets containing parent node information,
The third updating unit changes the transmission mark corresponding to the information item to the predetermined value when the determination result of the third determining unit is negative, and sets a preset forgetting time corresponding to the information item. To the initial value,
The node according to claim 2. The transmission means includes
An extraction module for extracting a transmission node from the data packet;
An additional module for adding a transmission node of the data packet to a data payload of the data packet;
A change module for changing the type of the data packet to a data packet including parent node information of a source node;
A transmission module for transmitting a data packet including parent node information,
The node according to claim 1. When the node is a transfer node, the transmission means transmits a message with an empty data payload to a gateway at a predetermined update period after first transferring a data packet of another node.
The node according to claim 1. Temporary storage means for temporarily storing the data packet including the parent node information after the transmission means transfers the data packet including the parent node information;
The transmission means deletes the data packet including the parent node information when transmission and reception of the data packet including the parent node information succeeds, and resends the data packet including the parent node information when the transmission fails.
The node according to claim 1. A gateway node in a multi-hop network,
Based on the received data packet including the parent node information, it is determined whether the downlink routing table stores an address of the source node of the data packet and an information item corresponding to the address of the parent node. 1 judging means,
When the determination result of the first determination means is negative, the address of the source node of the data packet and the address of its parent node are written in one information item of the downlink routing table, and the update time corresponding to the information item Or the update time and the expiration time corresponding to the information item are updated, and the update time corresponding to the information item in the downlink routing table is updated when the determination result of the first determination means is affirmative Or updating the update time corresponding to the information item in the downlink routing table and resetting the expiration time corresponding to the information item,
The downlink routing table includes a plurality of information items, each information item includes a node address, a parent node address, and an update time, or each information item includes a node address, a parent node address, an update time, and Gateway node, including expiration time. Second determination means for determining whether or not the expiration time of each information item of the downlink routing table has been reached;
If the determination result of the second determination means is affirmative, whether to delete the information item that has reached the expiration time or to store the information item that has reached the expiration time based on a predetermined rule A second update means for selecting, further comprising:
The gateway node according to claim 7. Query means for querying an adjacent node table to determine parent node information of a one-hop node in the multi-hop network;
The first update means writes the address of the one-hop node and the address of its parent node in one information item of the downlink routing table, updates the update time corresponding to the information item, or the information item Update the renewal time and expiration time corresponding to
The gateway node according to claim 7. An acquisition means for acquiring parent node information of the 2-hop node by monitoring a HELLO packet or an ACK packet transmitted from the 1-hop node of the multi-hop network to the 2-hop node;
The first updating means writes the address of the 2-hop node and the address of its parent node in one information item of the downlink routing table, updates the update time corresponding to the information item, or the information item Update the renewal time and expiration time corresponding to
The HELLO packet or the ACK packet includes transmission node information and reception node information, the transmission node is the 1-hop node, the reception node is the 2-hop node, and the transmission node information is the The parent node information of the 2-hop node,
The gateway node according to claim 7.

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