KR101043762B1 - Method and System for Network Configuration at Wireless Body Area Network - Google Patents

Abstract

The present invention proposes a method for constructing an energy efficient multi-hop network in a tree type wireless body network. The multi-hop network configuration method according to the present invention selects the parent node so that the overall power consumption is optimized while satisfying the packet transmission delay constraint when the switching node disconnected from another node selects the parent. Specifically, the switching node first broadcasts a paging message to inform the parent candidate node of the connection request and when selecting one of the parent candidate nodes responding to the paging message, the standard deviation of the remaining power values of all nodes is minimal. Select the parent node to be used. The present invention can be utilized in the recent wireless body network management for ubiquitous healthcare services.

Network management, wireless body network (WBAN), energy efficient configuration management,

Description

Method and system for configuring wireless body network {Method and System for Network Configuration at Wireless Body Area Network}

The present invention relates to a multi-hop network configuration method and a multi-hop network system. In more detail, when a node constituting a wireless body area network (WBAN) is disconnected from a connected node due to movement of a human body, power consumption between each node becomes constant among the reachable parent candidate nodes, The present invention relates to a multi-hop wireless body network configuration method and system for selecting a node capable of guaranteeing QoS (Quality of Service) and setting it as a new parent node.

Recently, research on wireless body network for ubiquitous health care service has been actively conducted mainly on IEEE. The wireless body network is often configured in a tree form of parent and child nodes based on multi-hop communication in consideration of power limitation and biometric characteristics. In this case, unlike the existing sensor network, there is a high possibility that the nodes connected to the network are disconnected due to frequent body movements, and there is a limit on the number of node connections that can be processed by each node due to the power consumption limitation of each node.

As society ages rapidly around the world, the number of chronically ill and elderly populations is increasing, and medical expenditures are rapidly increasing. In order to reduce such medical expenditures and to provide health care and medical services available “anytime, anywhere”, research on Ubiquitous (Healthcare Services) is being actively conducted. U-health care service is a basic function to acquire the body biometric information and remote monitoring, one way to obtain biometric information is the Wireless Body Area Network (WBAN).

A wireless body network is defined as a wireless communication within 3 meters from the inside of the human body and the human body based on the human body. In other words, the biometric information detected by the biometric sensor is transmitted to the user's gateway (PDA, notebook, PC, etc.) using a wireless body network so that the user's health status can be monitored remotely. However, since sensor nodes have a small data capacity and battery-based power consumption structure, there is a need for a method of guaranteeing quality of service (QoS) with minimal power consumption.

Although much research has been conducted on power consumption in the sensor network, the wireless body network environment is different from the traditional sensor network. Unlike traditional sensor networks, sensors in wireless body networks can be located inside the body, so biological properties and antenna height inside the body can affect packet loss. In addition, direct single-hop communication within the body, where biological properties must be considered, consumes high propagation costs and shortens battery life. Therefore, there is an urgent need for a study on power consumption in a multi-hop communication based wireless body network.

In particular, when a lot of child nodes require registration from a new parent node, it is necessary to solve the problem that a connection request of a child node cannot be handled due to the limited power and memory of the sensor node. If the connection with the server is lost, it is necessary to improve the problem of the quick connection setup of the broken node. In addition, when setting a new connection node when the connection with another node is lost, it is necessary to prevent a large difference in power consumption between the nodes.

The technical problem to be solved by the present invention is to solve the above problems, when setting up a new connection node when the connection to the other node is disconnected, multi-hop network configuration so that there is no significant difference in power consumption between each node To provide a way.

Another technical problem to be solved by the present invention is to solve the above problems, to provide a multi-hop network configuration method for enabling a fast connection of the disconnected node when the connection to the other node is disconnected.

Another technical problem to be solved by the present invention is to establish a new connection node when the connection with another node is lost, so that the number of hops with the root node does not exceed a certain number of times, and the delay time of the urgent packet is a predetermined limit. It is to provide a multi-hop network configuration method that does not exceed.

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

According to an aspect of the present invention, there is provided a method of configuring a multi-hop network, in which a switching node disconnected from another node broadcasts a paging message and among parent candidate nodes responding to the paging message. Setting one node to a parent node of the switching node. At this time, the parent node is a value of the remaining power of each node calculated on the assumption that all non-root nodes included in the network transmit a packet toward the root node in a network configuration in which the switching node is a child node of the parent node. Is the node whose standard deviation is minimal.

According to another aspect of the present invention, there is provided a method of configuring a multi-hop network, in which a switching node disconnected from another node broadcasts a paging message and among parent candidate nodes responding to the paging message. Setting one node as a parent node of the transfer node. However, the parent node is set based on the remaining power amount of the parent candidate node.

In the multi-hop network system according to another aspect of the present invention for achieving the above technical problem, when it is determined that the connection with the other multi-hop node, the connection with the other multi-hop node is disconnected, paging (paging) One of a switching determination unit generating a message and broadcasting through the interface unit, a storage unit storing remaining power amount data of all the multi-hop nodes included in the multi-hop network system, and a parent candidate node responding to the paging message; At least one multi-hop node including a parent node determining unit for setting the node as a parent node. In this case, the parent node determiner sets the parent node based on the amount of the remaining power stored in the storage.

According to the present invention as described above, when one node included in the multi-hop network is disconnected from the other node in setting up a new connection node, so as not to make a large difference in the amount of power consumption between each node, The number of hops does not exceed a certain number of times, and the delay time of urgent packets does not exceed a predetermined limit.

In addition, when a node included in a multi-hop network loses connection with another node, a node that stores urgent packets is provided by providing a multi-hop network configuration method that enables fast connection establishment in establishing a new connection node. Has the effect of transmitting the packet with a minimum delay.

Advantages and features of the present invention, and methods for achieving them will be apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms. The embodiments of the present invention make the posting of the present invention complete and the general knowledge in the technical field to which the present invention belongs. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, a method of configuring a multi-hop network according to embodiments of the present invention will be described with reference to the accompanying drawings. At this time, it will be understood that each of the steps in the process flowchart figures may be performed by computer program instructions. It is to be understood that these computer program instructions may be mounted on a processor of a special purpose computer or other programmable data processing equipment, and in particular may be executed on a sensor node making up a wireless human body network.

The topology of a multi-hop network configuration according to the present invention may include at least a part of a tree topology.

Hereinafter, a method of configuring a multi-hop network according to an embodiment of the present invention will be described with reference to FIG. 1. 1 is a flowchart illustrating a method of configuring a multi-hop network according to the present embodiment.

The switching node disconnected from another node is disconnected from the node that was connected (S100). If the synchronization data received at regular intervals is not received even after a certain period of time, the connection may be detected as disconnected. The cause of the disconnection may be greater than the communication radius of the distance between other nodes due to the positional movement of the transfer node. For example, in a network configuration in which a node installed at the fingertip is connected to a node installed at the side, when the target of the wireless human network moves a hand and moves out of the communication radius with the node installed at the side, the hand The node installed in will detect the disconnection with the node installed in the side (S100). The transfer node may be a leaf node.

The switching node broadcasts a paging message (S102). The paging message may be a response request message in a predefined format. The paging message is received by another node within the communication radius of the switching node. The other node receiving the paging message transmits a response message.

The transfer node receives the response message (S104). The transfer node determines the node that sent the response message as a parent candidate node.

The switchover node sets one of the parent candidate nodes responding to the paging message as a parent node of the switchover node. However, in the parent node, the remaining power amount value of each node calculated on the assumption that all non-root nodes included in the network transmit packets in the direction of the root node in the network configuration in which the switching node is a child node of the parent node. Should be a node whose standard deviation is minimum (S106). Hereinafter, it should be noted that setting as a parent node includes forming a communication channel between a parent node and a child node.

In order to obtain a standard deviation when the switching node is incorporated as a child node of each parent candidate node, the switching node preferably stores data on the amount of power of each node. The data on the amount of power preferably includes data on the amount of power remaining in each node and data consumed when transmitting and receiving packets. In addition, the data on the amount of power may be collected by the root node and distributed to all nodes in the network.

The standard deviation can be calculated by the formula published in Table 1.

Table 1: Equation for calculating standard deviation of remaining power values of each node

Referring to each symbol shown in Table 1 as follows. The set of nodes in which the number of connected nodes among the nodes in the entire network is s is {N ₁ , N ₂ ,. , N _s }. Since there may be another node that is not currently connected among the nodes included in the entire network, it may be understood that the standard deviation is calculated only for the currently connected node.

P (N _i ) is a value obtained by calculating the amount of power remaining after node i transmits a packet toward the root node. m is an average of remaining power amounts after all nodes included in the network transmit packets toward the root node. Therefore, when the value is calculated, it can be seen that the standard deviation of the remaining power amount values of each node calculated based on the assumption that all the non-root nodes included in the network transmit the packet toward the root node.

For each of the parent candidate nodes, the transfer node calculates the standard deviation under the assumption that the child node is a child node, and sets the parent candidate node having the smallest standard deviation value as the parent node. For example, when there are three parent candidate nodes, that is, when three nodes respond to the paging message, the standard deviation value is calculated three times, and among them, the parent candidate node having the smallest standard deviation value is selected. Is set to the parent node.

When setting the parent node, the switching node may be set in consideration of whether the number of hops between the parent node and the root node is less than or equal to a hop threshold. The hop threshold may be a predetermined value. That is, since the parent node is set so that the number of hops to the root node does not exceed a predetermined hop threshold, there is an effect that helps to guarantee QoS.

The hop threshold may be a value set based on an ordered pair of the root node and the parent node. That is, the hop threshold may not be previously designated with a single value as a whole, but different values may be specified according to the ordered pairs of the root node and the parent node.

In setting the parent node, the communication delay time calculated on the assumption that the switch node transmits an emergency packet to the parent node in a network configuration in which the switch node is a child node of the parent node is less than a preset delay time limit. It may be set in consideration of whether or not. The delay time threshold may be 100 milliseconds (ms) proposed by IEEE 802.15 TG (Task Group) 6. The emergency packet refers to a packet having an emergency level assigned to the packet or more. The urgency may be included in packets transmitted and received by each node of the present network.

Hereinafter, another multi-hop network configuration method according to another embodiment of the present invention will be described with reference to FIG. 2. 2 is a flowchart of a multi-hop network configuration method according to the present embodiment.

The switching node disconnected from another node is disconnected from the node that was connected (S200). If the synchronization data received at regular intervals is not received even after a certain period of time, the connection may be detected as disconnected. The cause of the disconnection may be greater than the communication radius of the distance between other nodes due to the positional movement of the transfer node. For example, in a network configuration in which a node installed at the fingertip is connected to a node installed at the side, when the target of the wireless human network moves a hand and moves out of the communication radius with the node installed at the side, the hand The node installed in the will detect that the connection with the node installed in the side (S200). The transfer node may be a leaf node.

The transfer node broadcasts a paging message (S202). The paging message may be a response request message in a predefined format. The paging message is received by another node within the communication radius of the switching node. The other node receiving the paging message transmits a response message.

The transfer node receives the response message (S204). The transfer node determines the node that sent the response message as a parent candidate node.

The switchover node sets one of the parent candidate nodes responding to the paging message as a parent node of the switchover node. However, the parent node is set based on the remaining power amount of the parent candidate node (S206). For example, the transfer node may set a node having the highest amount of current remaining power among the parent candidate nodes as a parent node, or set a node having the least amount of current remaining power among the parent candidate nodes as a parent node.

However, when the switching node is newly incorporated as a child node of the parent node, and the parent node communicates with too many child nodes, the parent node consumes more power than other nodes, which is a battery replacement. There is a problem of shortening the cycle. Therefore, the multi-hop network configuration method according to the present embodiment determines whether the parent node has exceeded the threshold degree after the parent node setting step S206 (S208). The degree is an integer representing the number of child nodes owned by one node. The limit order is preferably a predetermined value. For example, if the limit order is designated as 5, each node may own only up to 5 child nodes.

If the parent node exceeds the limit order as a result of the determination (S208), one of the child nodes is disconnected. Among the child nodes, it is preferable to disconnect (S210) the child node having the lowest urgency of the stored packet. Since it is possible to guarantee the transmission of the current packet by maintaining the connection of the high urgency child node, it is effective in guaranteeing QoS.

The disconnected node broadcasts a paging message to reconnect. The disconnected node sets one of the parent candidate nodes responding to the paging message as a parent node of the disconnected node. The parent node of the remaining power amount values of each node calculated on the assumption that all the non-root nodes included in the network transmit a packet toward the root node in the network configuration in which the disconnection node is a child node of the parent node. It is preferable that the node has a minimum standard deviation (S212).

The standard deviation may be calculated by the formula shown in Table 1, and may be calculated by the same method as described in the above-described embodiment, which will be omitted.

When establishing a parent node, the disconnection node may be configured by further considering whether the number of hops between the parent node and the root node is less than or equal to a hop threshold. The hop threshold may be a predetermined value. That is, since the parent node is set so that the number of hops to the root node does not exceed a predetermined hop threshold, there is an effect that helps to guarantee QoS.

The hop threshold may be a value set based on an ordered pair of the root node and the parent node. That is, the hop threshold may not be previously assigned a single value as a whole, but may be different from each other according to an ordered pair of the root node and the parent node.

In setting a parent node, a communication delay time calculated based on the assumption that the disconnection node transmits an emergency packet to the parent node in a network configuration in which the disconnection node is a child node of the parent node, has a preset delay time limit. It may be set considering further whether or not. The delay time threshold may be 100 milliseconds (ms) proposed by IEEE 802.15 TG (Task Group) 6. The emergency packet refers to a packet having an emergency level assigned to the packet or more. The urgency may be included in packets transmitted and received by each node of the present network.

Hereinafter, a method of configuring a multi-hop network according to the present embodiment will be described with reference to FIGS. 3 to 6.

First, Table 2 is a table showing the amount of power remaining and the urgency of owned packets to be applied to this example.

<Table 2: Remaining Power of Each Node and Priority of Owned Packets>

The urgency is indicated by N: non-urgent packet, U: urgent packet.

First, FIG. 3 is an initial node configuration of a multi-hop network. Hereinafter, it is assumed that the limit order is 2, and the communication radius of each node is 40 cm.

As shown in FIG. 2, when the subject of the wireless human network raises his arm, a method of configuring a multi-hop network according to the present invention will be described.

Node J broadcasts a paging message, and nodes K, H, and L, which are within J's communication radius, transmit a response message. K, H, and L become parent candidate nodes.

J sets the H node having the smallest residual current among K, H, and L as a parent node. It should be noted that selecting a node with the smallest residual amount of current is just one example and may select a node with the largest amount of current.

As a result of J setting H node as a parent node, it can be seen that H node exceeds the limit order.

The H node must disconnect from one of the child nodes J, L, and K. The K node is disconnected because only K nodes among J, L, and K own non-urgent packets.

As shown in FIG. 3, the K node broadcasts a paging message. The G, H, and J nodes present in the paging message within the communication radius of K transmit a response message and become parent candidate nodes of the K node.

K node simulates each of G, H, J nodes as a parent node and becomes a child node of each node, and each node calculated by assuming that all non-root nodes included in the network transmit packets toward the root node. Simulate that the standard deviation of the remaining power values of is minimized. In this example, it is assumed that the standard deviation becomes minimum when the K node becomes a child node of the G node.

As shown in FIG. 4, the K node sets the G node as the parent node.

Hereinafter, the configuration and operation of a multi-hop network system according to another embodiment of the present invention will be described with reference to FIG. 7. 7 is a block diagram showing the configuration of a multi-hop network system according to the present embodiment.

As shown in FIG. 7, the multi-hop network system according to the present embodiment includes one or more multi-hop nodes 700. The multi-hop node 700 communicates with other multi-hop nodes 700 to form a multi-hop network system according to the present embodiment. Multi-hop node 700 preferably communicates wirelessly with other multi-hop nodes 700. The multi-hop node 700 may be, for example, a node constituting a wireless human body network (WBAN).

As shown in FIG. 7, the multi-hop node 700 includes a switching determination unit 702, a parent node determination unit 704, a child node manager 706, a storage unit 708, and an interface unit 710. can do.

The interface unit 710 performs wireless communication with other multi-hop nodes 700.

When the transfer determination unit 702 determines that the connection with the other multi-hop node 700 is disconnected, the transfer determination unit 702 generates a paging message and broadcasts it through the interface unit 710. When the transfer decision unit 702 does not receive a sync message periodically transmitted / received with the other multi-hop node 700, it is preferable to determine that the connection with the other multi-hop node 700 is disconnected.

The parent node determiner 704 sets one node among the parent candidate nodes responding to the paging message as the parent node. In this case, the parent node determination unit sets the parent node based on the amount of the remaining power amount stored in the storage unit 708. For example, a node having the largest remaining power amount among the parent candidate nodes may be set as a parent node, or a node having the smallest remaining power amount among the parent candidate nodes may be set as a parent node.

The storage unit 708 stores remaining power amount data of all the multi-hop nodes included in the multi-hop network system. The storage unit 708 stores power consumption data when transmitting and receiving packets of all the multi-hop nodes included in the multi-hop network system, and emergency data of packets stored by all the multi-hop nodes included in the multi-hop network system, respectively. It may further include.

When the node determined to be disconnected from other multi-hop nodes 700 becomes a child node of the parent node, the child node manager 706 exceeds the limit order when the degree of the parent node exceeds the limit order. Disconnects one of the node's child nodes. The degree means the number of child nodes. The limit order means a maximum value of the number of child nodes that a node can have. The child node manager 706 may disconnect the child node having the lowest urgency of the packet stored in the storage 708 among the child nodes. This is because the node with the lowest urgency of the stored packet is disconnected for a while and then reconnected does not cause a big problem in the QoS of the network.

The disconnected multi-hop node 700 must be reconnected to the network using the new multi-hop node 700 as a parent node. Hereinafter, the reconnection operation will be described.

When the transfer determination unit 702 determines that the connection with the parent node has been released, the transfer determination unit 702 generates a paging message and broadcasts it through the interface unit 710.

The parent node determining unit 704 sets one node among the parent candidate nodes responding to the paging message as a parent node of the disconnection node, wherein the parent node is configured to have the multi-hop node disconnected from the parent node. In the network configuration set as the child node of the parent node, a multi-hop node having a minimum standard deviation of the remaining power values calculated on the assumption that all non-root nodes included in the network transmit packets in the direction of the root node. To be

That is, the first multi-hop node 700 that is disconnected is quickly connected to the network by using the multi-hop node 700 having the largest or smallest remaining power among other multi-hop nodes 700 responding by broadcasting a paging message. After connecting, when the parent node is connected to a child node exceeding a limit order, the parent node disconnects the node with the lowest urgency of the owned packet, and the released node again broadcasts a paging message and responds to the other node. It will be understood that a new parent of the multi-hop nodes 700 will be established, and the new parent will be a multi-hop node with a minimum standard deviation of the remaining power values of each node.

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

1 is a first embodiment of a multi-hop network configuration method according to an embodiment of the present invention.

2 is a second embodiment of a multi-hop network configuration method according to an embodiment of the present invention.

3 is a first state diagram of an embodiment of a multi-hop network configuration method according to an embodiment of the present invention.

4 is a second state diagram of an embodiment of a multi-hop network configuration method according to an embodiment of the present invention.

5 is a third state diagram of an embodiment of a multi-hop network configuration method according to an embodiment of the present invention.

6 is a fourth state diagram of an embodiment of a multi-hop network configuration method according to an embodiment of the present invention.

7 is a configuration diagram of a multi-hop network system according to an embodiment of the present invention.

Claims (13)

Broadcasting, by a transfer node disconnected from another node, a paging message; And Setting one node of a parent candidate node responsive to the paging message as a parent node of the transfer node, The parent node is a standard of the remaining power amount values of each node calculated on the assumption that all non-root nodes included in the network transmit a packet toward the root node in a network configuration in which the switching node is a child node of the parent node. A method of configuring a multi hop network, which is a node with minimum deviation. The method of claim 1, Broadcasting the paging message, A method of constructing a multi-hop network, comprising the step of broadcasting a paging message by a switching node that is disconnected because its distance from another node exceeds a communication radius. The method of claim 1, And wherein the parent node is established by further considering whether the number of hops with the root node is less than or equal to a hop threshold. The method of claim 3, wherein And the hop threshold is a value set based on an ordered pair of the root node and the parent node. The method of claim 1, The parent node is a communication delay time calculated on the assumption that the transfer node has sent an emergency packet to the parent node in a network configuration in which the transfer node is set as a child node of the parent node, whether the communication delay time is less than or equal to a preset delay time limit. How to configure a multi-hop network that is set up with more consideration. Broadcasting, by a transfer node disconnected from another node, a paging message; And Setting one node of a parent candidate node responsive to the paging message as a parent node of the transfer node, And the parent node is configured based on the amount of power remaining of the parent candidate node. The method of claim 6, If the switchover node becomes a child node of the parent node and the degree of the parent node exceeds a limit order, disconnecting one of the child nodes of the parent node. Configuration method. The method of claim 7, wherein Disconnecting one of the child nodes of the parent node, Disconnecting the child node having the lowest urgency of the stored packets among the child nodes. The method of claim 7, wherein After the disconnecting of one of the child nodes of the parent node, the disconnecting node broadcasting a paging message; And Setting a node of one of the parent candidate nodes responsive to the paging message as a parent node of the disconnect node; The parent node of the remaining power amount values of each node calculated on the assumption that all the non-root nodes included in the network transmit a packet toward the root node in the network configuration in which the disconnection node is a child node of the parent node. A method of configuring a multi-hop network where the node has a minimum standard deviation. An interface unit performing wireless communication with another multi-hop node; A switching determination unit generating a paging message and broadcasting through the interface unit when it is determined that the connection with another multi-hop node is lost; A storage unit which stores remaining power amount data of all the multi-hop nodes included in the multi-hop network system; And At least one multi-hop node including a parent node determining unit for setting one of the parent candidate node in response to the paging message as a parent node, The parent node determining unit sets the parent node based on the amount of the remaining power stored in the storage unit. 11. The method of claim 10, The multi-hop node, When the node determined to be disconnected from the other multi-hop node becomes a child node of the parent node and the degree of the parent node exceeds the limit order, the connection of one of the child nodes of the parent node is lost. The multi-hop network system further comprising a child node management unit to release. The method of claim 11, The storage unit, Further storing the amount of power consumed to transmit and receive packets and the urgency data of the stored packets to all the multi-hop nodes included in the multi-hop network system; The child node manager, The multi-hop network system of disconnecting the child node of the lowest urgency of the packet stored in the storage unit of the child node. 13. The method of claim 12, The transfer determination unit, If it is determined that the connection with the parent node has been released, a paging message is generated and broadcasted through the interface unit. The parent node determination unit, Set one node of the parent candidate node responding to the paging message as a parent node of the disconnection node, The parent node is calculated on the assumption that all non-root nodes included in the network transmit packets in the direction of the root node in a network configuration in which the multi-hop node disconnected from the parent node is a child node of the parent node. A multi-hop network system, which is a multi-hop node with a minimum standard deviation of remaining power values of each node.

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