KR101567071B1 - Method for reducing address waste in low power wireless personal area network - Google Patents

Abstract

A method for reducing address waste in a low power wireless personal area network, comprising: checking a location between a new node and a coordinator node; transmitting a join request message to the coordinator node; Transmitting an address request message to a parent node of the coordinator node if the available address is found, receiving the available address information from the coordinator node when the available address is found, And assigning an address to the node.

Address waste, available address, new node

Description

[0001] METHOD FOR REDUCING ADDRESS WASTE IN LOW POWER WIRELESS PERSONAL AREA NETWORK [0002]

The present invention relates to a method for reducing address waste in a low power wireless personal area network (LoWPAN).

Generally, a personal area network (PAN) is a concept compared with a local area network (LAN) or a wide area network (WAN), and the PAN has a network unique to each individual. The PAN can be used in various fields such as a wireless sensor network and a home network. For example, the PAN implemented using Institute of Electrical and Electronics Engineers (IEEE) 802.15.4 standard is LoWPAN, which is a kind of wireless sensor network.

LoWPAN has a hierarchical sensor network and supports external interface. The LoWPAN includes a PAN coordinator, a coordinator or a full function device (FDD) that supports routing, and a routing function to manage routing and synchronization with nodes. And a Reduced-Function Device (RFD). The PAN coordinator manages addresses to be assigned to all nodes included in the LoWPAN. Since the number of allocated addresses has hierarchical network structure and address system like Zigbee and energy efficiency should be considered, the range of the number of nodes corresponding to the number of allocated addresses is fixedly allocated.

The coordinator or the FFD allocates an address unique to the RFD or its child nodes entering the communicable area of its own, and the address assigned to the child nodes is an address of the address managed by the PAN coordinator It is one. At this time, the FFD or RFD is assigned an address for communication with the parent node from a parent node in a 1-hop relationship with the FFD or RFD. The parent node may be a coordinator or FFD that supports the routing function.

Address management in the hierarchical allocation fixed allocation method leads to address waste in LoWPAN. In the initial network configuration, if all the nodes are evenly distributed, there is no waste of addresses. However, it is not configured to artificially allocate and check the sensor node, but it is automatically configured when the initial node is configured. Nondestructive node configuration is virtually impossible and some address wastage is inevitable.

In particular, if additional nodes need to be expanded after adding new nodes in the initial state without the number of nodes in the initial state, if all the nodes in the region have allocated the maximum number of child addresses, It is not possible to use the new PAN coordinator, thereby forming a new LoWPAN network by adding a new PAN coordinator, or reallocating the addresses of all the nodes.

1 is a diagram illustrating an address management method in a conventional LoWPAN.

Even if an attempt is made to expand a new node as shown in FIG. 1, if all the neighboring nodes have allocated all available addresses, even if there are available spare addresses in other areas, they can not be used and a new LoWPAN network must be formed do.

2 is a flowchart illustrating a process of entering a LoWPAN of an existing new node.

Referring to FIG. 2, in step 201, the new node searches for a parent node located in an adjacent space. If the parent node is found, the new node sends a join request message to the parent node in step 203. If the parent node receives the join request message in step 205, it determines whether there is an address to be assigned to the new node. If there is an address to be allocated, the process proceeds to step 207, and an address is assigned to the new node. If there is no address to be allocated, the process proceeds to step 209 and a new node is transmitted.

However, as described above, the hierarchical address fixed distribution scheme such as Zigbee is fixed according to the initial network configuration, so address waste may occur. In addition, since the number of all constituent nodes in the LoWPAN is wasted, Capacity. This may require unnecessary configuration of a new PAN coordinator.

As described above, the address management policy or algorithm in the LoWPAN considers only the fixed nodes, and efficient address management scheme considering address waste is needed by using the limited resource amount and energy efficiency of the LoWPAN.

It is an object of the present invention to provide a method for reducing address waste in a LoWPAN using available available addresses.

According to an aspect of the present invention, there is provided a method for reducing address waste in a low power wireless personal area network, the method comprising: broadcasting a beacon request message to find a coordinator node at a distance adjacent to the new node; Transmitting the address information of the new node to the new node; and transmitting, by the coordinator node, the coordinator node, when the new node transmits the network join message to the coordinator node, And a step in which the coordinator node transmits an address request message to its parent node and determines whether the parent node has an available address, if there is no available address, and if the child node or the parent node includes an available address If there is an available address, It characterized in that the step of transmission by a coordinator node updates the address information of the coordinator node, and, based on the updated address information, comprising the step in which the coordinator node assigns the address available to the new node.

If there is no available address in the coordinator node to which the new node belongs, the coordinator node draws an available address from another node and allocates the available address to the new node. Therefore, the available address in the network can be used freely, It is possible to minimize waste.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be appreciated that those skilled in the art will readily observe that certain changes in form and detail may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims. To those of ordinary skill in the art.

The present invention proposes a method for reducing address waste in a low power wireless personal area network (LoWPAN).

Prior to describing the present invention, a range from a corresponding coordinator to one hop in the LoWPAN is referred to as a communicable region, and nodes communicating within a range of one hop are defined as child nodes of a coordinator, (Parent node). A parent node is a node that manages routing in its communicable area. When a connection request is received from nodes located in a communicable area from an address pool, an address that is not currently used in the address pool is allocated to the parent node And assigns the connection request to the received nodes. The address pool contains unique addresses obtained from the coordinator of the personal area network. Also, each node includes an address information table for managing the address allocation state, and this table is updated when the state of the stored address is changed.

Also, in the address allocation, the address allocation is sequentially allocated to the nodes within the range, and the present invention is performed when the new node does not join the network formed around the parent node. The basic algorithm of the present invention is as follows.

First, the new node selects one of its parent nodes located close to itself and transmits a network join message. This subscription message is repeatedly transmitted at predetermined time intervals. The selected parent node can be defined as a coordinator node. The coordinator node receiving the network join message generates an address request message and sends it to its child node. Here, the coordinator node may broadcast an address request message in consideration of the address state of the child nodes and the depth of the current network in order to obtain the latest address information from the child node thereof.

When broadcast is used, a beacon request is transmitted to a child node without using a message, and a child node receiving the beacon may transmit its own free address information to a beacon payload. The child node having the free address transmits its own free address information to the coordinator node. If there is no free address, it sends an address request message to its child node again.

If there is no response to the address request message, the coordinator node sends the address request message back to its parent node. The parent node of the coordinator node receiving the address request message transmits an address request message to its child node, and if there is no response, the address request message is transmitted to the grandparent node again. This process is repeated until the node having the free address is found.

If a node with a free address is found, the coordinator node receives the address information of the corresponding node from its child node or the parent node, updates the address information, and receives the network join request message again from the new node. When a join request message is received from the new node, the coordinator node receives the network join response message and allocates the address to the new node.

The present invention will be described in detail with reference to the following examples based on the above basic algorithm.

3 is a flowchart illustrating an address allocation process of a new node in an address depleted state according to an embodiment of the present invention. In FIG. 3, it is assumed that all the addresses allocated to the parent node are used first.

Referring to FIG. 3, in step 301, the new node broadcasts a beacon request message to all channels through a scanning process in order to subscribe to a desired LoWPAN network. The broadcasted beacon request message is received by all the parent nodes adjacent to the new node. In step 303, one or more parent nodes that have received the beacon request message transmit a response message to the new node. The response message contains information about the address allocation state of the parent node. A new node that has received one or more response messages can know how many parent nodes exist at a location adjacent to itself and can also know how much the parent node is allocating addresses.

In step 305, the new node selects a specific parent node from among the parent nodes that transmitted the response message, and proceeds to step 307 to transmit a join request message to the selected parent node (the selected parent node is defined as a coordinator node). When transmitting a request message, it is possible to send a message by selecting a parent node including an available address. However, since it is assumed that all the addresses allocated to the parent node are used as assumed above, Select as coordinator.

The coordinator node selected in step 309 transmits an available address pool message indicating that there is no available address to the new node that has transmitted the subscription request message because all the addresses allocated to the coordinator node are used. In step 311, when the new node receives the available address pool message, it waits for a preset time.

In step 313, the coordinator node transmits an address request message to its parent node while the new node is waiting. The parent node receiving the address request message confirms whether there is a free address. If all the addresses are used by the child nodes of the parent node, the address request message is sent again to the parent node of the parent node. In this way, an address request message is sent until an available address is found. If the available address is confirmed, the coordinator node receives the address response message in step 315. The order of receiving the address response message proceeds in the reverse order in which the address request message was sent. For example, if the available address is identified at the grandparent node of the coordinator node, the grandparent node sends the address response message to the parent node and the parent node sequentially sends the address response message to the coordinator node.

In step 317, the coordinator node stores and updates available address information included in the received address response message in its own address information table. Of course, all nodes that have received an available address response message also delete the available address from their tables.

In step 319, the new node transmits a beacon request message to the coordinator node again after a predetermined time elapses. In step 321, the coordinator node transmits a response message to the new node, and in step 323, the new node sends a subscription request message to the subscription request message. In step 325, the coordinator node having received the join request message transmits the join response message to the new node to assign an address. The subscription response message includes the available address information. In step 327, the new node receiving the subscription response message stores the available address information in its own table.

4 and 5 are exemplary diagrams illustrating a procedure for assigning an available address to a new node according to an embodiment of the present invention.

Referring to FIG. 4, the node H sets a coordinator node (node G) through transmission and reception of a beacon request message and a response message as shown in FIG. 3, transmits a join request message to the coordinator node, .

Node G, which is a coordinator node, is using all the available addresses of its address information table, and therefore transmits an address request message to node E, which is its parent node. Node E also sends an address request message to its parent node, Node B, because it is using all the available addresses in its address information table. The node B finds that there is an available address among the addresses in its address information table, and transmits an address request message to the node D corresponding thereto. Node D again retransmits to node F and receives a message containing an available address (Start Address = 923D, Counter = 2). After sending the message, the node F deletes the corresponding available address from its address information table. Where Counter represents the number of available addresses.

The node D sends a message containing the available address information from the node F to the node B, and the nodes D and B update the address status information of the nodes to their own table. The node B and the node E sequentially transmit the message including the available address information to the node G. [

The node G updates the received address information in its own address information table. After that, the node H allocates an available address at the time of joining the network and updates the table with information that the available address is being used.

FIG. 5 is a diagram illustrating a procedure for assigning an available address to a new node according to an embodiment of the present invention. The method for obtaining the available address is not so different from FIG. 4, and therefore, description of FIG. 5 is omitted.

4 and 5, when a new node sends a network join message to a coordinator node, even if the coordinator node itself does not have an available address, it transmits an address request message to a child node or a parent node of the coordinator node, Lt; / RTI > When a node having an available address is found, the coordinator node receives the information of the available address, stores it in its own address table, updates it, and assigns it as a new node, thereby enabling communication without having to configure the network separately.

6 is a diagram illustrating an address management method in a LoWPAN according to an embodiment of the present invention. FIG. 6 shows a process in which a new node is formed into a single LoPAN rather than a single new node.

Referring to FIG. 6, when node A has five child nodes and node A transmits a join request message to an adjacent coordinator node, the coordinator node fetches six available addresses including node A from itself or its parent node . Herein, the child nodes of the node A do not have to request the coordination request message to the coordinator node, respectively, and the node A transmits the join request message to the coordinator node by including the required number of the available nodes including the node itself in the join request message, When a node sends as many available addresses as needed to node A, node A again distributes the available address to its child nodes.

As described above, a method of reducing address waste in a low-power wireless personal area network according to an exemplary embodiment of the present invention can be configured and operated. While the present invention has been described with respect to specific embodiments, May be practiced without departing from the scope of the present invention. Accordingly, the scope of the present invention should not be limited by the illustrated embodiments, but should be determined by equivalents of the claims and the claims.

1 is a diagram showing an address management method in a conventional LoWPAN;

FIG. 2 is a flowchart showing a process of entering a LoWPAN of an existing new node

3 is a flowchart illustrating an address allocation process of a new node in an address depleted state according to an embodiment of the present invention.

4 and 5 are diagrams illustrating an example of a procedure for assigning an available address to a new node according to an embodiment of the present invention.

6 is a diagram illustrating an address management method in a LoWPAN according to an embodiment of the present invention.

Claims (10)

A method for reducing address waste in a low power wireless personal area network, A step in which the new node and the coordinator node check each other, Receiving, by the coordinator node, a subscription request message from the new node; The coordinator node receiving information of an available address from another node; And the coordinator node allocating an address to the new node based on the received available address information, The process of the new node and the coordinator node checking each other, Wherein the coordinator node broadcasts a beacon request message broadcast by the new node to select a desired coordinator node among at least one coordinator node located at a distance adjacent to the new node, To the new node. delete 2. The method of claim 1, And transmits the beacon request message to all channels to join the low power wireless personal area network. 2. The method of claim 1, And transmitting the join request message to the coordinator node periodically according to a predetermined time. 2. The method of claim 1, wherein the coordinator node And generates an address request message and transmits the generated address request message to its parent node if there is no available address among the addresses assigned to the node. 2. The method of claim 1, wherein the coordinator node receives information of an available address from another node, Allocating the available address to the new node when the available address is present; And if the parent node has an available address, storing information of the available address in its own address information table and updating the parent node, and the parent node having the available address deletes the available address information How to reduce address waste. 7. The method of claim 6, wherein the coordinator node And storing the available address information in its own address information table. When the new node transmits the join request message again, the new node transmits a join response message including the available address information to the new node. Way. 2. The method of claim 1, wherein the step of assigning an address to the new node comprises: Transmitting a join request message to the coordinator node after the new node waits for a preset time; And allocating to the new node an available address that the coordinator node has or received from the parent node. The method according to claim 1, Wherein the parent node of the coordinator node determines whether there is an available address, and if there is no available address, transmits an address request message to the parent node of the parent node. The method according to claim 1, Wherein the coordinator node allocates as many available addresses as the number of child nodes of the new node and the new node to the new node when the new node includes a child node.

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