KR20100004971A - Method for routing a path setting in a wireless sensor network and apparatus for performing the same - Google Patents

Abstract

PURPOSE: A method for setting a routing path in a wireless sensor network and an apparatus for performing the same are provided to search a node close to a destination to which a packet is transmitted to transmit a packet, thereby reducing a hop count number according to packet transmission. CONSTITUTION: A logic processor(100) comprises a sensor device and a memory. A hardware processor comprises an adjacent node information management module. The adjacent node information management module uses an adjacent table saved in the memory to manage adjacent node information. An antenna(300) wirelessly connects an external node with the hardware processor.

Description

METHOD FOR ROUTING A PATH SETTING IN A WIRELESS SENSOR NETWORK AND APPARATUS FOR PERFORMING THE SAME}

The present invention relates to a routing path establishment method and an apparatus for performing the same, and more particularly, to a routing path establishment method and apparatus for performing the same in a wireless sensor network.

A general mobile communication system transmits and receives data between a mobile terminal and a base station. The mobile station and the base station directly transmit and receive data without passing through other mobile terminals / nodes. However, a sensor network uses other sensor nodes when it wants to transfer data of a sensor node to a sink node.

Hereinafter, the structure of the wireless sensor network will be described with reference to FIG. 1. As shown in FIG. 1, the wireless sensor network consists of a sink node and a plurality of sensor nodes. Although FIG. 1 illustrates only one sink node, the wireless sensor network may consist of at least two sink nodes according to a user's setting.

The sensor node collects information about a target set by a designated user. Target information collected by the sensor node may include ambient temperature or movement of an object. The sensor node transmits the collected information to the sink node.

The sink node receives data transmitted by sensor nodes constituting the wireless sensor network. The sensor node located within a certain distance from the sink node directly transmits data to be transmitted to the sink node. However, a sensor node not located within the predetermined distance transmits the collected data to sensor nodes adjacent to the sink node instead of directly transmitting the collected data to the sink node.

As described above, the reason why a node that is not located within a certain distance transmits data by using adjacent nodes is to minimize power consumption due to data transmission. That is, the distance between the sink node and the sensor node and the power consumed by the sensor node to transmit data to the sink node are generally proportional to each other.

Therefore, the sensor node that is not located within a certain distance from the sink node can minimize the power consumption due to the data transmission by transmitting the collected data using a plurality of sensor nodes. Hereinafter, a node that plays a role of relaying data of another sensor node is called a relay node. Of course, the relay node also transmits the data collected by the relay node to another sink node or directly.

As described above, the sensor node collects information of the target and delivers the information to the sink node. In general, however, the target and sink nodes are not fixed but are somewhat mobile.

2 is a diagram illustrating a process of delivering information about a fixed target to a sink node with guaranteed mobility. For example, this is the case when the temperature information on a specific area is transmitted to a moving vehicle. In this way, the vehicle receives real-time temperature information about the specific area. Meanwhile, FIG. 3 illustrates a process of transmitting information about a target with guaranteed mobility to a fixed sink node. For example, this is the case where information about a moving object is transferred to a fixed sink node.

4 illustrates a process of setting a routing path for transmitting a data to a sink node by a sensor node in a general wireless sensor network. Hereinafter, a process in which the sensor node 1 establishes a routing path to the sink node will be described with reference to FIG. 4.

The sensor node 1 generates a routing request (RREQ) message including its address (source address) information and sink node address (destination address) information. The sensor node 1 broadcasts the generated routing request message to neighboring sensor nodes.

4, the sensor node 2, the sensor node 4, and the sensor node 5 receive the RREQ message. The sensor nodes receiving the RREQ message compare the destination address with their own address. If the destination address and its address are not the same, the sensor nodes update the received RREQ message and then broadcast it to neighbor nodes. The updated information includes the hop count number.

In addition, the sensor node receiving the RREQ message generates a routing table using the received RREQ message. The routing table includes an address of a source node, an address of a destination node, a hop count number, and an address of a sensor node broadcasting the RREQ message.

The RREQ message broadcast by the sensor node 1 is delivered to the sink node through various paths. The sink node establishes a routing path using the hop count number included in the delivered RREQ message. That is, the path with the smallest hop count is set as the routing path. Accordingly, the sink node sends a message to the sensor node 4 with a routing reply (RREP). The sensor node 4 transmits the RREP message to the sensor node 1 using the stored routing table. By performing the above-described processes, a routing path between the sensor node 1 and the sink node is established. The sensor node 1 transfers the collected information to the sink node by using the set routing path.

Technical challenge

Accordingly, the technical problem of the present invention has been made in view of the above, and an object of the present invention is to provide a routing path setting method in a wireless sensor network for transmitting a packet with a short path using neighboring node information.

Another object of the present invention is to provide an apparatus for performing the routing path establishment method in the wireless sensor network.

Technical solution

In order to realize the above object of the present invention, a routing path setting method in a wireless sensor network according to an embodiment of the present invention is a routing path setting method in a wireless sensor network transmitting a packet between a source node and a destination node, (a) As the routing begins, the source node searches for its neighbor nodes; (b) if the destination node includes the destination node, sending a packet to the destination node and ending the routing; (c) if the destination node is not included in the neighbor nodes, searching for a node closest to the destination node among the neighbor nodes and transmitting a packet to the nearest node; And (d) the nearest node searches for its neighbor nodes and feeds back to step (b).

In this embodiment, the hop count number at which the packet is transmitted is smaller than the hop count number hierarchically connecting the source node and the destination node.

In this embodiment, the neighbor nodes are obtained from the neighbor table of the source node.

In order to achieve the above object of the present invention, a routing path setting method in a wireless sensor network according to another embodiment includes: (a) configuring a current node, a destination node, and a next hop node closest to the current severity and the destination node; step; (b) calculating a first hop distance on a hierarchical routing path from the current node to the destination node and a second hop distance on a hierarchical routing path from the nearest next hop node to the destination node; (c) establishing a next hop node on the hierarchical routing path; (d) querying the neighbor table to extract the neighbor node information queried from the neighbor table; (e) calculating a third hop distance on a hierarchical routing path from the neighbor node to the destination node; (f) comparing the first hop distance with the third hop distance; (g) if the first hop distance is less than or equal to the third hop distance, checking whether the full search of the neighbor table is completed; (h) if it is checked that the search for the neighbor table is incomplete, returning to step (d) of querying the neighbor table; and if the search for the neighbor table is completed, the packet is sent to the next hop node. Doing; (i) comparing the second hop distance with the third hop distance if the first hop distance is greater than the third hop distance; And (j) if the second hop distance is greater than the third hop distance, setting the inquired neighbor node as the next hop node, and then feeding back to the step (g).

In order to achieve the above object of the present invention, an apparatus for setting a routing path in a wireless sensor network according to an embodiment includes a destination node, a source node, and a next hop node. The destination node finally receives the packet. The source node searches for the first neighboring nodes as the routing for transmitting the packet starts, and if the destination node is not included in the first neighboring nodes, the source node is closest to the destination node among the first neighboring nodes. Send a packet to the node. The next hop node retrieves second neighboring nodes as the packet is received from the source node, and transmits the packet to the destination node or the closest node to the destination node.

In the present embodiment, when the source node includes the destination node in the searched neighbor nodes, the source node transmits a packet to the destination node.

In this embodiment, there is one destination node and one source node.

In this embodiment, the next hop node is one or more.

In this embodiment, the hop count number at which the packet is transmitted is smaller than the hop count number hierarchically connecting the source node and the destination node.

In this embodiment, the neighbor nodes are obtained from the neighbor table of the source node.

In order to realize the above object of the present invention, a routing path setting apparatus in a wireless sensor network according to an embodiment includes a logic processor, a hardware processor, and an antenna. The logic processor includes a sensor device and a memory. The hardware processor includes a neighbor node information management module managing neighbor node information by using a neighbor table stored in the memory. The antenna wirelessly connects an external node with the hardware processor. The logic processing unit and the hardware processing unit finally receive a packet from the external node during operation of the destination node. The logic processing unit and the hardware processing unit search for the first neighboring nodes during operation of a source node, and if the destination node is not included in the first neighboring nodes, the logic processing unit and the hardware processing unit are located at a node closest to the destination node among the first neighboring nodes. Send the packet.

In the present embodiment, the logic processing unit and the hardware processing unit search for the second neighbor nodes as the packet is received from the source node during the next hop node operation. Subsequently, the packet is transmitted to the destination node or the node closest to the destination node among the second neighbor nodes.

Favorable effect

As described above, according to the present invention, hierarchical routing may be performed by using a dynamically allocated 16-bit short address on a wireless sensor network, for example, a low-power wireless personal area network (6LoWPAN) based on Internet Protocol version 6. Can be. In particular, by using the neighbor node information on the wireless sensor network, routing hierarchically, searching for a node close to the destination where the packet is transmitted, and transmitting the packet, thereby reducing the number of hop counts due to packet transmission.

In addition, by reducing the number of hop counts required for hierarchical routing, routing time required for transmitting a packet can be reduced.

In addition, by reducing the total hop count, it is possible to reduce the traffic generated during routing and to reduce the power consumption of the nodes.

1 is a conceptual diagram illustrating the structure of a wireless sensor network.

2 is a conceptual diagram illustrating a moving target in a wireless sensor network.

3 is a conceptual diagram illustrating a sink node moving in a wireless sensor network.

4 is a conceptual diagram illustrating a process of setting a routing path in a wireless sensor network.

5 is a conceptual diagram illustrating a configuration of a wireless sensor network suitable for applying the present invention.

6 shows an example of a wireless sensor network protocol stack suitable for application of the present invention.

7 is a diagram illustrating a header format of a general IPv6.

FIG. 8 shows an example of a data frame format of the MAC / PHY layer shown in FIG. 6.

9 is a conceptual diagram illustrating a multi-hop tree according to the present invention.

10 is a block diagram illustrating a sensor node for performing a method for establishing a hierarchical routing path according to the present invention.

11 is a conceptual diagram illustrating an address assignment method according to a first embodiment of the present invention.

12 is a conceptual diagram illustrating a routing path setting method using the address assignment method shown in FIG. 11.

13 and 14 are conceptual diagrams illustrating a routing path establishment method according to a second embodiment of the present invention.

15 is a flowchart illustrating a hierarchical routing path setting method according to a second embodiment of the present invention.

Best Mode for Carrying Out the Invention

Hereinafter, various embodiments of a method and apparatus for setting a routing path in a wireless sensor network according to various aspects of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is limited to the following embodiments. The present invention may be embodied in various other forms without departing from the technical spirit of the present invention.

The main terms used in connection with the present invention are defined as follows.

Current Node refers to a node on a wireless sensor network, that is, when an IEEE 802.15.4 device receives an IPv6 packet.

Depth means the hop-distance from the coordinator: 10 of the wireless sensor network to the device. For example, the depth of coordinator 10 is zero.

Maximum Number of Children (MC) is the maximum number of children the device (eg node) can have.

A neighbor table refers to a table that contains information of neighboring devices in a personal operating space (POS). The neighbor table includes a personal area network ID (PAN Id: 16 bits), a neighbor short address (Neighbor. 16 bit short address: 16 bits), a neighbor EIU 64 address (Neighbor.IEEE EUI 64 bit address). (64 bits), a neighbor device type (Neighbor. Device type: 2 bits), a neighbor relationship (Neighbor.Relationship: 2 bits), and a neighbor depth (Neighbor.Depth: 8 bits). In the neighbor table, if a Neighbor Device Type (2 bits) field is '00', it represents a coordinator, '01' represents a router, and '10' represents an end device. '11' is reserved. In the neighbor table, if a neighbor relationship (2 bits) field is '00', it represents a parent, and if it is '01', it represents a child, and '10' and '11' are reserved. have.

-Personal Area Network ID (PAN Id) means a wireless sensor network 16-bit identifier assigned to the wireless sensor network for management. Here, a personal operating space (POS) means an area within a detection range of wireless transmission of an IEEE 802.15.4 packet.

Reduced Function Device (RFD) is an IEEE 802.15.4 device in a wireless sensor network that does not have a router function and cannot transmit IPv6 packets to a next hop device. That is, the partial function device can only be an end device on the wireless sensor network.

A router is an FFD that can route packets to a next hop device on a wireless sensor network, and a short address is a 16-bit address dynamically assigned to the device from its parent.

An internet protocol version 6 based wireless sensor network suitable for application of the present invention is as shown in FIG. 5. In this embodiment, the wireless sensor network is Low Power Wireless Personal Area Networks (LoWPAN).

5 is a conceptual diagram illustrating a configuration of a wireless sensor network suitable for applying the present invention. 6 shows an example of a wireless sensor network protocol stack suitable for application of the present invention.

Referring to FIG. 5, the wireless sensor network consists of one PAN coordinator 10, a plurality of routers 20a, 20b, 20c and termination devices 30a, 30b, 30c, 30d, 30e.

According to the IEEE 802.15.4 specification, devices in a wireless sensor network are a full function device (FFD) that implements a complete protocol set of IEEE 802.15.4, and a reduced function that does not have a router function. Device: hereinafter referred to as RFD). The PAN coordinator 10 and the routers 20a, 20b, and 20c are FFD devices, and the terminators 30a, 30b, 30c, 30d, and 30e are RFD devices.

The FFD supports all network types supported by IEEE 802.15.4, can exchange data between the FFD and RFD, can act as a PAN coordinator, and performs all the functions described in IEEE 802.15.4.

In comparison, the RFD is designed to be suitable for smaller and lighter devices. These devices have the effect of lowering the price of energy by reducing the energy consumption rate as much as possible with simple functions and simple operation, minimizing the use resources, and lowering the chip implementation price.

The RFD can be used only as an end device in all network types. This means that RFDs can't send peer-to-peer data because they don't have routing capabilities and can't act as PAN coordinators.

The star shape, which consists of RFD and FFD with various functions in one PAN coordinator, can solve the lack of wireless interface of home network, PC peripheral, toy, game console, health care device, etc. Peer-to-Peer communication may utilize ad-hoc routing capabilities provided by the network layer. This can be applied to a variety of sensor networks, remote controls, actuators, and the like.

Devices of a wireless sensor network according to the IEEE 802.15.4 standard are connected to a parent device and a child device on the network. The child device is dynamically assigned a 16-bit short address from the parent device through association.

That is, the IEEE 802.15.4 device may be dynamically allocated a short address of 16 bits during association with a neighbor device (or router), also called a parent device. Only the assigned short address can know communication with the parent or child. On the other hand, disassociation is a procedure for removing an existing association with a neighboring device.

The PAN coordinator (10) is a full-function device (FFD) that becomes the most important manager of the wireless sensor network. The PAN coordinator 10 may initiate synchronization of the entire wireless sensor network through the transmission of beacons.

The terminators 30a, 30b, 30c, 30d, and 30e may be connected to any one of the routers 20a, 20b, and 20c to communicate with the terminator connected to the router. The routers 20a, 20b, and 20c route packets received from at least one or more of the end devices 30a, 30b, 30c, 30d, and 30e or from another router according to the hierarchical routing path setting method according to the present invention. do.

6 shows an example of a wireless sensor network protocol stack suitable for application of the present invention.

Referring to FIG. 6, protocols of a physical layer (L1), a MAC (MAC) layer (L2), an adaptation layer (L3), and an IPv6 layer (L4) are mounted on the wireless sensor network protocol stack. TPC, UDP, and ICMP are located on the IPv6 (L4), and the application layer is located thereon.

The physical layer (L1) and MAC layer (L2) is in accordance with the IEEE 802.15.4-2003 standard, the adaptation layer (L3) is IETF Internet draft (montenegro-lowpan-ipv6-over-802.15.4) The IPv6 layer (L4) is in accordance with RFC 2460 and related standards.

An IPv6 header format applied to the present invention is shown in FIG. 7 below.

7 is a diagram illustrating a header format of IPv6 applied to the present invention. FIG. 8 shows an example of a data frame format of the MAC / PHY layer shown in FIG. 6.

Referring to FIG. 7, the IPv6 header format has a size of 10 rows x 32 bits = 40 octets, version, priority, flow level, payload length, next header, hop limit, 128 bits of source address, and 128 bits. Consists of the destination address.

In addition, the frame according to the IEEE 802.15.4-2003 standard is a beacon frame for transmitting beacons in the coordinator, a data frame for transmitting data, a response frame for notifying the other party when the data frame is successfully received, MAC command It is divided into frames.

Referring to FIG. 8, the data frame of the MAC / PHY layer includes a packet format of the physical layer and a packet format of the MAC layer.

The packet format of the physical layer includes a preamble sequence, a start of frame delimiter, a frame length, and a MAC layer data unit (MPDU).

The packet format of the MAC layer includes a frame control, a sequence number, an addressing field, a data payload, and a frame check sequence (FCS).

Each device of the wireless sensor network to which the present invention is applied may be represented as a node of a tree having multiple hops, as shown in FIG. 9 below.

9 is a conceptual diagram illustrating a multi-hop tree according to the present invention. For convenience of description, the same reference numerals are given to the same configuration of the wireless sensor network shown in FIG. 5.

Referring to FIG. 9, Node A corresponding to a root in the tree structure is a PAN coordinator and a depth is '0'. Node B, Node D, and Node F are routers, and Node C, Node E, Node G, Node H, and Node I are end devices.

The nodes are low power communication devices each having a wireless communication function. The nodes may each be a source node that generates data or an intermediate node that relays data from a source node and a destination node to a destination node or intermediate data. In addition, each node may be connected to other nodes in a hierarchical structure.

10 is a block diagram illustrating a sensor node for performing a hierarchical routing path setting method according to the present invention.

Referring to FIG. 10, the sensor node for performing the hierarchical routing path setting method according to the present invention includes a logic processor 100, a hardware processor 200, and an antenna 300.

The logic processor 100 may include an application module 110, a sensing processing module 120, an IP processing module 130, an adaptive layer packet processing module 140, a routing processing module 150, and a neighbor node information management module 160. ), The MAC layer module 170. In this embodiment, the logic processing unit 100 is logically separated, but not hardware separated.

The hardware processing unit 200 includes a sensor device 210 for performing observation of an environment, a central processing unit (CPU) 220, a memory 230, a network device 240 for communicating, and a flash memory for performing long-term recording of data. 250.

Typically, in wireless sensor networks, eg, ZigBee networks, each node is provided in a table with information for managing and maintaining the network. The information stored in the table is called a network information base (NWK IB). The network information base may be stored in the memory.

The network information base stores the maximum number of children, the maximum depth of the network tree, the maximum number of ZigBee routers that can be a child, the information related to broadcast transmission, the neighbor table having the information of neighbor nodes, the route table, and the security related information. Include.

The neighbor table stores information such as a PAN identifier, a 64-bit address of its parent or child, a 16-bit network address, a device type, and a relationship between itself and a neighbor node (eg, parent, child, neighbor).

The neighbor table includes the neighbor node's receiver during the superframe's activity period, 64-bit address of all neighbors, beacon instruction (order), authority to participate in the network, transmission failure rate, potential parent, average link quality indicator (link). information such as a quality indicator, a logical channel value, a beacon frame arrival time, and a beacon transmission time offset may be selectively stored.

The route table stores information used when searching a route to transmit data from a multihop network to a destination.

The memory 230 stores information of neighbor nodes. The neighbor node information may be provided via the MAC layer module 170. The service of the MAC layer module 170 includes beaconing. The neighbor node information is used in the routing processing module process to find a short path.

Meanwhile, the sensor device 210 may include a temperature sensor, a humidity sensor, an illuminance sensor, an infrared sensor, or the like.

The network device 240 may be in bidirectional communication with another node having a particular identifier. For example, Blue Tooth, IEEE802.15.4, ZigBee, etc. may be mounted on the network device 240.

Packet information arriving at the network device 240 is processed via the MAC layer module 170 and then provided to the adaptation layer packet processing module 140. The adaptation layer packet processing module 140 performs a packet processing process. The packet processing process includes header parsing, packet fragmentation (separation / reassembly), header compression, and the like.

Packets arriving at them by adaptive layer packet processing are delivered to the application module 110 via the IP processing module 130. The IP processing module 130 performs a routing process if the packet is to be routed.

The sensor node may be operated as a source node to which a packet is transmitted, may be operated as a next hop node (or a relay node) to deliver the packet, or may be operated as a destination node to which the packet is delivered.

In a routing operation, there is one source node and one destination node, and one or more next hop nodes. Of course, if the source node and the destination node are placed closest, the next hop node can be omitted.

When the sensor node is the source node, as the routing for transmitting the packet starts, the first neighbor nodes are searched for. In the above search, if the destination node is not included in the first neighbor nodes, the packet is transmitted to a node closest to the destination node among the first neighbor nodes. The sensor node transmits a packet to the destination node when the searched neighbor nodes include the destination node.

When the sensor node is a next hop node, as packets are received from the source node, the second neighbor nodes are searched for, and the packet is transmitted to the destination node or the node closest to the destination node among the second neighbor nodes. send.

Accordingly, the hop count number at which the packet is transmitted is smaller than the hop count number hierarchically connecting the source node and the destination node.

11 is a conceptual diagram illustrating an address assignment method according to a first embodiment of the present invention. In particular, it is described that an address is given under the condition of MC = 3.

Referring to FIG. 11, node 1 is disposed at a top level, and node 1 is connected to node 2, node 3, and node 4 as child nodes. Thus, the node 2, the node 3, and the node 4 are connected to node 1 as a parent node.

The child node refers to a node connected directly below the node with respect to any one node (arbitrary node) in a hierarchical structure. On the other hand, the parent node is a concept in contrast to the child node, and refers to a node that is directly connected to the top of the node for any one node. Here, the connection means a logical connection or a wireless connection, not a physical connection or a wired connection.

The node 2 is connected to nodes 5, 6 and 7 as child nodes, and the node 5 is connected to nodes 14, 15 and 16 as child nodes. Thus, nodes 5, 6 and 7 are connected to node 2 as parent nodes, and nodes 14, 15 and node 16 are connected to node 5 as parent nodes.

Node 6 is a child node and is connected to node 17, node 18 and node 19. Thus, node 17, node 18 and node 19 are connected to node 6 as a parent node.

The node to which an address is to be assigned determines its own child and, if there is no child, allocates an address according to Equation 1 below. In the embodiment of the present invention, it is assumed that every node knows its depth.

Equation 1

FC = MC * AP + 1

Here, FC is the address of the child node, MC is the maximum number of children, AP is the address of the parent node. If there was no child before the parent was connected, the new child becomes the first child and receives a new short address by Equation 1 above.

If the new child is not the first child of the parent, then the IEEE 802.15.4 device receives the address of the parent's existing child plus one. For this assignment the router must maintain a neighbor table with address information of the child and parent.

On the other hand, if there are child nodes, the address is allocated by adding '1' to the largest address among the child nodes.

In the routing path setting method according to the first embodiment of the present invention, a path for routing a packet is calculated as follows.

An ancestor node defined as 'C', current node's depth as 'DC', destination node's address as 'D', and node K's depth D ) Is defined as 'AA (D, K)'. Here, the current node is a node that a packet passes through in the routing process.

If the current node belongs to the ancestor group of the destination node, the address of the next hop node (or next transmitting node) is 'AA (DC + 1, D)'. On the other hand, if the current node belongs to the descendant group of the destination node, the address of the next hop node is 'AA (DC-1, C)'. In other cases, the address of the next hop node is 'AA (DC-1, C)'. In this case, the ancestor node refers to nodes connected to an upper level of the node with respect to any one node (arbitrary node) in the hierarchical structure and includes the above-described parent node. On the other hand, the descendant node is a concept in contrast to the ancestor node, and refers to nodes connected to the lower part of the node for any one node (arbitrary node) in a hierarchical structure.

An example of a packet transmission method according to the first embodiment of the present invention described above will be described with reference to FIG.

12 is a conceptual diagram illustrating a routing path setting method using the address assignment method shown in FIG. 11. In particular, when the source node is node 14 and the destination node is node 19, a routing path establishment method will be described.

Referring to FIG. 12, the parent node of node 14 is node 5. FIG. At this time, node 5 is the current node. However, node 5, which is the current node, does not belong to the ancestor group of node 19 in the destination mode, nor to the descendant group. Thus, the address of the next hop node is the parent node of node2. At this time, the node 2 is the current node.

Node 2, the current node, belongs to the ancestor group of the destination node. Thus, the address candidate of the next hop node is node 6 or node 7. However, since node 7 does not belong to the ancestor group of the destination node, the address of the next hop node is node 6. Node 6 is the current node.

Node 6, the current node, belongs to the ancestor group of the destination node. Thus, the address candidates of the next hop node are node 17, node 18 and node 19. However, the routing process is terminated because the destination node exists in the address candidate. The packet is transmitted to node 19 via node 5, node 2, and node 6 as a relay node between node 14, which is the source node and node 19, which is thus configured.

In the first embodiment of the present invention described above, the packet to be transmitted is delivered to the next hop node (parent node or child node) on the path from the source node to the destination node. Each time a packet is passed through the next hop node, routing takes a long time and a lot of traffic.

13 and 14 are conceptual diagrams illustrating a routing path establishment method according to a second embodiment of the present invention. For convenience of description, it is assumed that the topology of the multi-hop tree illustrated in FIGS. 13 and 14 is the same as that of the multi-hop tree illustrated in FIG. 11. The routing path setting method may be applied to a wireless sensor network, for example, low power wireless personal area networks (LoWPAN).

First, as shown in Fig. 13, node 14, which is the source node, searches for the node closest to node 19, which is the destination node, among its neighboring nodes. In this embodiment, the neighbor nodes of the source node are node 2, node 5, node 15 and node 16. Among the above-described nodes 2, 5, 15 and 16, node 2 having a close hop distance to the destination node is selected as the next hop node.

Subsequently, as shown in FIG. 14, node 2 at which the packet arrives searches for a node closest to node 19 which is a destination node among its neighbor nodes. In the present embodiment, the neighbor nodes of node 2 are node 1, node 5, node 6, node 17, node 18 and node 19. Here, node 2, which is a destination node, is included, so node 2 transmits the arrived packet to node 19.

As a result, in the same topology, the routing path establishment method according to the second embodiment may confirm that the total hop distance is reduced from four hops to two hops, compared to the routing path establishment method according to the first embodiment.

15 is a flowchart illustrating a hierarchical routing path setting method according to a second embodiment of the present invention.

Referring to FIG. 15, as the hierarchical routing operation is started, a source node, a destination node, and a next next hop node between the source node and the destination node are set (step S105).

Subsequently, a first hop distance on a hierarchical routing path from the source node to the destination node and a second hop distance on a hierarchical routing path from the nearest next hop node to the destination node are calculated (step S110).

Next, a next hop node on the hierarchical routing path is set (step S115).

Next, the neighbor table is queried (step S120), and the neighbor node information queried from the neighbor table is extracted (step S125).

Subsequently, a third hop distance on the hierarchical routing path from the neighbor node to the destination node is calculated (step S130).

Next, the first hop distance and the third hop distance are compared (step S135).

Then, if the first hop distance is less than or equal to the third hop distance, it is checked whether the search of the entire neighbor table is completed (step S140). If it is checked that the search for the entire neighbor table is incomplete, the process returns to step S120 for querying the neighbor table.

When it is checked that the search for the entire neighbor table is completed, the packet is transmitted to the next hop node (step S145), and the hierarchical routing operation is terminated.

In step S135, when the first hop distance is greater than the third hop distance, the second hop distance and the third hop distance are compared (step S150).

When the second hop distance is greater than the third hop distance, the inquiry neighbor node is set as the next hop node (step S155), and the feedback is returned to the step S140.

As described above, although described with reference to the preferred embodiments of the present invention, those skilled in the art various modifications and variations of the present invention without departing from the spirit and scope of the present invention described in the claims below You will understand that it can be changed.

A hierarchical routing operation is performed utilizing a dynamically allocated 16-bit short address on a wireless sensor network, for example, a low power wireless personal area network (6LoWPAN) based on Internet Protocol version 6. In particular, by routing the hierarchically using neighbor node information on the wireless sensor network, searching for a destination where a packet is transmitted or a node close to the destination and transmitting the packet, the number of hop counts due to packet transmission can be reduced. In addition, since the number of hop counts is reduced, routing operations can be speeded up, and traffic generated between nodes can be reduced.

Claims (12)

In a routing path setting method in a wireless sensor network transmitting a packet between a source node and a destination node, (a) as the routing begins, the source node searches for its neighbor nodes; (b) if the destination node includes the destination node, sending a packet to the destination node and ending the routing; (c) if the destination node is not included in the neighbor nodes, searching for a node closest to the destination node among the neighbor nodes and transmitting a packet to the nearest node; And and (d) the nearest node searching for its neighbor nodes and feeding back to step (b). The method of claim 1, wherein the number of hop counts over which the packet is transmitted is smaller than the number of hop counts hierarchically connecting the source node and the destination node. The method of claim 1, wherein the neighboring nodes are obtained from neighboring tables of the source node. (a) establishing a current node, a destination node and a nearest next hop node between the current urgency and the destination node; (b) calculating a first hop distance on a hierarchical routing path from the current node to the destination node and a second hop distance on a hierarchical routing path from the nearest next hop node to the destination node; (c) establishing a next hop node on the hierarchical routing path; (d) querying the neighbor table to extract the neighbor node information queried from the neighbor table; (e) calculating a third hop distance on a hierarchical routing path from the neighbor node to the destination node; (f) comparing the first hop distance with the third hop distance; (g) if the first hop distance is less than or equal to the third hop distance, checking whether the full search of the neighbor table is completed; (h) if it is checked that the search for the neighbor table is incomplete, returning to step (d) of querying the neighbor table; and if the search for the neighbor table is completed, the packet is sent to the next hop node. Doing; (i) comparing the second hop distance with the third hop distance when the first hop distance is greater than the third hop distance; And (j) if the second hop distance is larger than the third hop distance, setting the inquired neighbor node as the next hop node, and then feeding back to the step (g). How to set up routing paths on the sensor network. A destination node for finally receiving a packet; As routing for transmitting a packet is started, the first neighbor nodes are searched, and if the destination node is not included in the first neighbor nodes, the packet is transmitted to the node closest to the destination node among the first neighbor nodes. A source node for transmitting; And And a next hop node that searches for second neighbor nodes as the packet is received from the source node, and transmits the packet to the destination node or the closest node to the destination node among the second neighbor nodes. A device for performing a routing path establishment method on a wireless sensor network. The method of claim 5, wherein the source node, And transmitting a packet to the destination node when the found neighbor nodes include a destination node. 6. The apparatus of claim 5, wherein there is one destination node and one source node. 6. The apparatus of claim 5, wherein the next hop node is one or more. 6. The apparatus of claim 5, wherein the number of hop counts over which the packet is transmitted is smaller than the number of hop counts hierarchically connecting the source node and the destination node. 6. The method of claim 5, wherein the neighboring nodes are obtained from a neighbor table of the source node. In an apparatus for performing a routing path setting method in a wireless sensor network for transmitting a packet between a source node and a destination node, A logic processor including a sensor device and a memory; A hardware processor including a neighbor node information management module managing neighbor node information by using a neighbor table stored in the memory; And An antenna for wirelessly connecting an external node with the hardware processor; The logic processing unit and hardware processing unit, In operation of the destination node, finally receiving a packet from the external node, In operation of a source node, when a first neighbor node is searched and a destination node is not included in the first neighbor nodes, a packet is transmitted to a node closest to the destination node among the first neighbor nodes. An apparatus for performing a routing path establishment method on a wireless sensor network. The method of claim 11, wherein the logic processing unit and hardware processing unit, In a next hop node operation, when a packet is received from the source node, the second neighbor nodes are searched and the packet is transmitted to the destination node or the node closest to the destination node among the second neighbor nodes. An apparatus for performing a routing path establishment method on a wireless sensor network.

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