KR101475934B1 - Mode controlling node and method thereof in an ad-hoc network - Google Patents

Abstract

A node included in an ad hoc network stores a node table including information on the number of active neighbor nodes and node status, receives a packet from a neighbor node, transmits a packet to a neighbor node, And if the number of active neighbor nodes is greater than or equal to the threshold value, a random number between 0 and the number of active neighbor nodes is set as a random number If the random number is greater than or equal to the threshold value, the node status is set to passive. If the random number is smaller than the threshold value, the node status is set to active. If the number of active neighbor nodes is smaller than the threshold value, By setting the state to be active, conflicts and storms of broadcast packets can be overcome.

Description

[0001] MODE CONTROLLING NODE AND METHOD THEREOF IN AN AD-HOC NETWORK [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a node for controlling its own state and a control method thereof, and more particularly to a node for controlling its own packet transmission / reception state included in an ad hoc network and a control method thereof.

Ad-hoc networks do not require underlying network devices such as base stations or access points or specific network connection rules to configure and maintain the network. The ad-hoc nodes communicate with each other by using a wireless interface, overcome the restriction on the communication distance of the wireless interface by the multi-hop routing function, and the network phase is dynamically changed have.

The broadcast transmission method is a method in which a sender transmits data to all the receivers on the same subnetwork. In this case, the broadcast packet transmitted in the ad hoc network includes various transmission and reception processes such as paging, alarm signal transmission and routing. .

Broadcast packets are easy to use and implement but have the drawbacks of redundant re-broadcast, competition, and collision. A broadcast storm is a phenomenon in which broadcast packets are generated on a network due to a failure of a network device or a loop in a bridge, and a broadcast storm problem occurs due to the disadvantage of the broadcast packet described above.

In this regard, Korean Patent Laid-Open No. 10-2008-7019687 (entitled " Communication method and apparatus relating to operation in cooperative and non-cooperative mode) discloses a method of selecting and switching between operations of communication devices in cooperative and non- And devices have been described.

The present invention overcomes the limitations of the prior art such as redundant packet transmission / reception, competition, and collision due to unnecessary packets transmitted by nodes when the number of neighboring nodes is large, and overcomes the broadcast storm caused thereby.

The present invention also attempts to overcome the limitations of the prior art in which all nodes are affected even when only some nodes are locally clustered in the prior art.

According to an aspect of the present invention, there is provided a node included in an ad hoc network according to the first aspect of the present invention includes a node table storing information on the number of active neighbor nodes, ; A transmitting and receiving unit receiving a packet from a neighboring node or transmitting a packet to a neighboring node; And a controller for comparing the number of active neighbor nodes with a predetermined threshold value and setting the state of the node as active or passive according to a result of the comparison, And if the random number is greater than or equal to the threshold, sets the node state to passive, and if the random number is greater than or equal to the threshold, And sets the state of the node to active when the number of the active neighbor nodes is smaller than the threshold value.

A method for controlling a state of a node included in an ad hoc network according to the second aspect of the present invention is characterized in that a node table storing state information and the number of active neighbor nodes is stored in the node, Comparing a number of the threshold values with a predetermined threshold value; And setting the state of the node as active or passive according to a comparison result of the comparing step, wherein when the number of the active neighbor nodes is greater than or equal to the threshold value, Active node sets a state of the node to active if the random number is less than a threshold, and if the random number is less than a threshold, The state of the node is set to passive, and if the number of the active neighbor nodes is smaller than the threshold value, the state of the node is set to be active.

According to the above-mentioned object of the present invention, it is possible to smoothly transmit and receive a node from a situation such as duplicate packet transmission / reception, competition, collision even when there are many nodes in the ad hoc network as a whole or locally.

1 illustrates an ad hoc network including a state control node according to the present invention.
FIG. 2 illustrates a configuration of a node included in an ad hoc network according to an embodiment of the present invention.
3 is an overall flowchart of a method of controlling a state of a node included in an ad hoc network according to the present invention.
4 shows a flowchart for updating information of a neighbor node stored in an entry.
5 illustrates in detail a process of updating the state of an active neighbor node according to an embodiment of the present invention.
FIG. 6 illustrates a process of updating a state of a node in accordance with an embodiment of the present invention.
7 shows the process of updating the state of the node according to the current state of the node.
8 is a graph for explaining the reason for generating the random number, and shows the state of the node according to the presence or absence of the random number.
FIG. 9 is a graph illustrating a result of an experiment of network transmission performance to which the present invention is applied in an AODV environment.
10 is a graph illustrating a result of an experiment of network transmission performance applying the present invention in a GPSR environment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between .

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise. The word " step (or step) "or" step "used to the extent that it is used throughout the specification does not mean" step for.

A node in accordance with an embodiment of the present invention cooperates with a routing protocol. The routing protocol informs the node of a broadcast packet among the received packets and confirms whether the broadcast packet should be transmitted to the node when it is necessary to transmit the broadcast packet.

In the present specification, an active state means a state in which a packet can be transmitted, and a passive state means a state in which a packet can not be transmitted.

The term " Active Neighbor Node Entry " refers to a node capable of transmitting a packet among neighbor nodes, and "Active Neighbor Node Entry" means an entry for storing information of an active neighbor node Which includes address information for storing address information of an active neighbor node and time information for storing time information of a last packet received from the corresponding active neighbor node.

In the present specification, the term "standby state" means a state in which a node waits for a state in which there is no transmission / reception of a packet.

At this time, each node may include an " active neighbor node table (hereinafter referred to as a table) ", which includes the state information of the node and the number of active neighbor nodes, but may further include an entry or a timer. However, the timer may be in addition to the table, node, or external device.

On the other hand, when the packet transmission / reception is not performed for a predetermined time, the entry of the active neighbor node is deleted and the number of active neighbor nodes is decreased. The node status is also changed to active. At this time, a state where the transmission / reception of the packet is not performed for a predetermined time may be a case where a preset time comes in the timer in the standby state, and this is referred to as " timeout " throughout the specification. The timer operates when there is no transmission or reception of a packet to the node.

The present invention can be varied flexibly according to the number of active neighbor nodes in an active or passive state. A broadcast packet can be transmitted when the node is active, but it can not be transmitted when the node is in the passive state. The node can know the number of active neighbor nodes by receiving the packet transmitted by the active neighbor node.

If the number of active neighbor nodes is greater than or equal to a predetermined threshold, the node operates in an active or passive state. However, if the number of active neighbor nodes is less than a predetermined threshold value, the node will operate in an active state. At this time, the threshold value can be preset by the user as the number of active neighbor nodes to be maintained including the node.

1 illustrates an ad hoc network including a state control node according to the present invention.

An ad-hoc network, also called a wireless ad-hoc network, is a method of establishing a network between wireless portable devices without infrastructure such as a base station. Recently, research on efficient routing algorithm in wireless ad-hoc network environment has been conducted with the rapid increase of the use of wireless portable devices having a short-range communication function such as wireless LAN and Bluetooth.

A wireless medium basically has a feature of transmitting data in a broadcast manner. When a plurality of nodes occupy a wireless medium, a transmission error occurs due to a data collision. Therefore, a transmission method considering characteristics of a wireless medium is needed.

The present invention overcomes the limitations of the prior art such as redundant packet transmission / reception, competition, and collision due to unnecessary packets transmitted by nodes when the number of neighboring nodes is large, and overcomes the broadcast storm caused thereby.

In this case, each node is connected to a neighboring node through a network, and the network may be a wired network such as a local area network (LAN), a wide area network (WAN), or a value added network (VAN) And may be implemented in any kind of wireless network, such as a mobile radio communication network or a satellite communication network.

FIG. 2 illustrates a configuration of a node included in an ad hoc network according to an embodiment of the present invention.

The node includes a storage unit 210, a transceiver unit 220, and a control unit 230, and may further include a timer. However, although not shown, the timer may be a node table 215 or an external device in addition to the node.

The storage unit 210 stores a node table 215. The table 215 includes node status information and information on the number of active neighbor nodes and includes an active neighbor node entry . In this case, the entry includes address information in which the address information of the active neighbor node is stored and time information in which the last time the packet was received from the active neighbor node is stored.

The transceiver 210 receives a packet from a neighboring node or transmits a packet to a neighboring node.

The controller 220 compares the number of the active neighbor nodes with the predetermined threshold value, and sets the state of the node as active or passive according to the comparison result.

If the number of active neighbor nodes is greater than or equal to the threshold value, the controller 220 sets the node state to passive. However, if the number of active neighbor nodes is less than the threshold value, the node state is set to active.

According to another embodiment of the present invention, if the number of active neighbor nodes is greater than or equal to a threshold value, a random number between 0 and the number of active neighbor nodes is generated. If the random number is greater than or equal to the threshold value, Is set to passive. However, if the random number is less than the threshold value, the node state is set to active.

The state control operation principle of the node in more detail will be described later with reference to FIG. 7 and FIG.

In addition, when the transceiver 220 receives a packet from a neighboring node, the controller 230 according to an exemplary embodiment of the present invention determines whether information about a neighboring node that transmitted the packet is stored in the entry. According to an embodiment of the present invention, whether or not the information on the neighboring node that transmitted the packet is stored in the entry can be confirmed by checking whether the address of the neighboring node is stored in the address information of the entry.

At this time, if the information about the neighboring node that transmitted the packet is stored in the entry, the controller 230 updates the neighboring node information of the entry. According to an embodiment of the present invention, when the address of the neighboring node that transmitted the packet is stored in the address information, the neighboring node updating unit 230 updates the time information of the corresponding entry to the time of receiving the packet of the neighboring node .

If the information on the neighboring node is not stored in the entry, the controller 230 generates a new entry, adds neighboring node information to the entry, and increases the number of active neighboring nodes. At this time, the neighbor node information is added according to an embodiment of the present invention, when the controller 230 generates a new entry and receives the address and the packet of the neighbor node that has transmitted the packet in the address information and the time information of the entry And increasing the number of active neighbor nodes of table 215 by the number of entries generated.

In addition, the controller 230 according to an exemplary embodiment of the present invention checks if there is an expired active neighbor node entry. If there is an expired active neighbor node entry, the controller 230 deletes the entry of the corresponding neighbor node, .

In addition, the controller 230 according to an embodiment of the present invention approves packet transmission when a node makes a packet transmission request in an active state. Here, the transmission request means a state in which the routing protocol of the node asks whether the packet transmission should be possible when the broadcast packet transmission is required.

The control unit 230 may initialize all the states of the node. At this time, if the predetermined time has elapsed in the timer in the waiting state, that is, when the timeout occurs, Initializes the number of active neighbor nodes in table 215, and deletes all entries. And sets the state of the node to the active state.

Also, even when the node boots, the controller 230 initializes the number of active neighbor nodes of the timer and the table 215, and sets the node state to the active state.

FIG. 3 is an overall flowchart of a method for a node included in an ad hoc network according to an embodiment of the present invention to control its own state.

According to an embodiment of the present invention, when a node is booted, the number of active neighbor nodes is initialized to zero and the timer is also initialized. It also sets the state of the node to active.

First, when a node receives a packet from a neighboring node in a standby state (S1110), a process will be described.

First, the neighbor node information stored in the entry is updated (S1120). The updating process will be described later in more detail with reference to FIG.

FIG. 4 shows a flow chart for updating information of the neighboring node in more detail.

At this time, if the information about the neighboring node is stored in the entry, the active neighboring node information of the entry is modified (S1121). According to an embodiment of the present invention, when the address of the neighboring node that transmitted the packet is stored in the address information of the entry, the time information of the entry is modified and updated to the time of receiving the packet of the neighboring node.

However, if the information about the neighboring node is not stored in the entry, a new neighboring node entry is created (S1125), information about the neighboring node is added to the entry, and the number of active neighboring nodes in the table of the node is updated (S1126). According to an embodiment of the present invention, address information of a new entry, time of receiving a neighbor node address and packet when the packet is transmitted to the time information is stored, and the number of active neighbor nodes of the table is Increases.

Referring again to FIG. 3, the state of the active neighbor node may be updated (S1130). FIG. 5 illustrates details of updating the state of the active neighbor node according to an embodiment of the present invention.

First, it checks whether there is an expired active neighbor node entry. If there is an expired active neighbor node entry, the entry of the corresponding neighbor node is deleted and the number of active neighbor nodes is decreased (S1131).

Next, the state of the node can be updated (S1140), and FIG. 6 illustrates in detail the process of updating the state of the node according to an embodiment of the present invention.

First, the number of active neighbor nodes is compared with the predetermined threshold value. If the number of active neighbor nodes is not equal to or greater than the threshold value, that is, if the number of active neighbor nodes is less than the threshold value, the state of the node is set to active and the process proceeds to the next step (S1141). However, if the number of active neighbor nodes is greater than or equal to the threshold value, the state of the node is set to passive according to an embodiment of the present invention (S1146).

However, according to another embodiment of the present invention, when the number of active neighbor nodes is greater than or equal to the threshold value, a random number between 0 and the number of active neighbor nodes is generated (S1145). If the random number is smaller than the threshold value, the state of the node is set to active and the process proceeds to the next step (S1141). On the other hand, if the random number is greater than or equal to the threshold, the state of the node is set to active and the process proceeds to the next step (S1146).

FIG. 7 shows the process of updating the state of this node according to the current state of the node.

In the active state, if there is a broadcast packet transmission request, depending on the condition, it is kept in an active state or set to a passive state as follows. And remains active when the number of active neighbor nodes is less than a preset threshold. If the number of active neighbors is greater than or equal to the threshold and the generated random number is less than the threshold, it remains active. On the other hand, if the number of active neighbor nodes is greater than or equal to the threshold value and the value of the random number is larger than the threshold value, the active node is set to the passive state.

In the passive state, if there is a broadcast packet transmission request, it is set to an active state or kept in a passive state according to a condition as follows. If the number of active neighbor nodes is less than the threshold value, the node is set to the active state. If the number of active neighbor nodes is greater than or equal to the threshold and the generated random number is less than the threshold, the node is set to the active state. On the other hand, if the number of active neighbor nodes is greater than or equal to the threshold value and the value of the generated random number is greater than or equal to the threshold value, the node remains in the passive state.

Here, FIG. 8 is a graph for explaining the reason for generating the random number, and shows the state of the node according to the presence or absence of the random number.

When the present invention does not generate a random number and the number of active neighbor nodes is equal to or greater than the threshold value and the state of the node is directly set to passive, the threshold is searched as the number of active nodes sharply shakes as shown in FIG. However, when the random number is used, the number of active nodes is linearly reduced, and the amount of packet transmission / reception can be controlled stably.

Then, according to an embodiment of the present invention, after determining whether or not to respond to the received packet, it updates the timer and waits again in the waiting state.

Referring to FIG. 3 again, a description will be given of a process in which the present invention operates when a node attempts to transmit a packet to a neighboring node in a standby state (S1210).

When the node requests packet transmission, the state of the active neighbor node and the state of the node are updated (S1230, S1240), and the process is the same as the active neighbor node state update process of FIG. 5 described above and FIGS. 6, Is the same as the node state updating process of FIG. 8 (S1130, S1140). The method further includes transmitting a broadcast packet if the node status is active, and ignoring the node's transmission request if the status is passive. The present invention updates the timer and waits again in the standby state.

Referring again to FIG. 3, when a timeout of a timer occurs in a standby state (S1310), the present invention performs the following operations.

The term "timeout" means a case in which a predetermined time has elapsed in a timer with no packet transmission / reception for a predetermined period of time. By this means, when a timeout of a timer occurs in a waiting state, , All entries stored in the node's table are deleted and the number of active neighbor nodes is initialized to zero. Also, the state of the node is set to active, and the timer is updated. The present invention then waits in the standby state again. In this case, the timer may be a node, a node controlling the state, or an external device in addition to the node table. The timer also operates when there is no packet transmission / reception to the node.

In this way, when the method of controlling the state of a node or node included in the ad hoc network of the present invention is used, it is possible to overcome the problem of the broadcast storm that occurs when the amount of packet transmission increases, The transmission performance is not degraded.

In order to confirm this, FIGS. 9 and 10 show graphs of results of experiments on network transmission performance applying the present invention in AODV and GPSR environments, respectively.

In the case of an ad hoc network, since there is no fixed infrastructure, mobile nodes must be able to transmit data. For this, each mobile node in the ad hoc network must perform the function of a general router. In this case, the routing path establishment protocol in the ad hoc network can be roughly classified into three types: a proactive or a table-driven routing protocol; the second is a reactive or demand- (On-demand) routing protocol, and the third is a hybrid protocol.

AODV (Ad hoc On-Demand Distance Vector Routing) is a representative request-based routing protocol and is a protocol that finds the routing path to the destination node when the source node needs data transmission.

GPSR (Greedy Perimeter Stateless Routing) is a representative geographical location-based routing protocol. Every node implementing GPSR knows its geographical location and geographical location of radio neighbors.

FIG. 9 shows a packet transmission rate when using AODV. denotes a threshold value of the present invention, and? indicates a packet transmission rate when the present invention is not applied.

9 (a), 9 (b) and 9 (c) show packet transmission rates in the case of 10, 20 and 30 fixed bit rates (CBRs), respectively. In all cases, as the number of nodes increases, the packet delivery rate decreases. This is because traffic of the network increases as the number of nodes increases. Also, as the fixed bit rate increases, the packet transmission rate decreases. This is because as the fixed bit rate increases, the number of data packets increases and the traffic of the network increases.

There is no significant difference in the packet delivery rate between the case where the present invention is applied and the case where the present invention is not applied in an environment where the number of nodes is small. However, as the number of nodes increases, there is a big difference in packet delivery rate. In the case of FIG. 8 (a), there is no significant difference even when the present invention is applied. This is because bandwidth is sufficient to transmit traffic even if all nodes transmit broadcast packets.

On the other hand, in the case of FIG. 8 (b), when the present invention is not applied, the packet transmission rate sharply decreases when the number of nodes increases. As the number of nodes increases with the increase of data packets, the number of broadcast packets also increases.

In the case of FIG. 9 (c), the data packet is excessively increased in comparison with the bandwidth, and the packet transmission rate is reduced even when the present invention is applied. However, when the present invention is applied, the packet delivery rate is higher than when the present invention is not applied.

는 본 발명의 임계값이며,

인 경우에는 본 발명을 적용하지 않은 상태의 패킷 전달율을 나타낸다. 도 10의 (a), (b), (c)는 10, 20, 30개의 고정 비트율(Constant Bit Rate, CBR)을 갖는 경우의 패킷 전송률에 대하여 도시한다. 모든 경우에 노드의 수가 증가할수록 패킷 전달율이 감소 한다. 이는 노드의 수가 증가할수록 네트워크의 트래픽이 많아지기 때문이다. FIG. 10 shows the packet transmission rate when GPSR is used.

Is a threshold value of the present invention,

The packet transmission rate in a state where the present invention is not applied. 10 (a), 10 (b) and 10 (c) show packet transmission rates in the case of 10, 20 and 30 fixed bit rates (CBRs). In all cases, as the number of nodes increases, the packet delivery rate decreases. This is because traffic of the network increases as the number of nodes increases.

Also, as the fixed bit rate increases, the packet transmission rate decreases. This is because as the fixed bit rate increases, the number of data packets increases and the traffic of the network increases. In the environment with a small number of nodes, there is no significant difference in the packet delivery rate between the case where the proposed algorithm is applied and the case where the proposed algorithm is not applied. However, as the number of nodes increases, there is a big difference in packet delivery rate. In the case of FIG. 10 (a), there is no significant difference even if the present invention is applied. This is because bandwidth is sufficient to transmit traffic even if all nodes transmit broadcast packets.

In the case of FIG. 10 (b), when the present invention is not applied, the packet delivery rate sharply decreases when the number of nodes increases. As the number of nodes increases with the increase of data packets, the number of broadcast packets increases.

In the case of FIG. 10C, the data packet is excessively increased in comparison with the bandwidth, and the packet transmission rate is reduced even when the present invention is applied. However, when the present invention is applied, the packet delivery rate is higher than when the present invention is not applied.

When the ad hoc routing protocol transmits a broadcast packet, a problem of broadcast storm occurs. Various methods have been proposed to solve this problem, but there still existed a problem in that the performance is rapidly reduced in a packet transmission network. Also, there is a problem that the performance is rapidly reduced even when nodes are locally crowded.

The present invention proposes a technique of maintaining excellent performance even in a network with many packet transmissions by using a method of controlling the number of nodes capable of transmitting broadcast packets not exceeding a threshold value. And this method is applied to AODV and GPSR, and it shows excellent performance.

2 and 3 according to an embodiment of the present invention refer to a hardware component such as software, a field programmable gate array (FPGA), or an application specific integrated circuit (ASIC) Lt; / RTI >

However, 'components' are not meant to be limited to software or hardware, and each component may be configured to reside on an addressable storage medium and configured to play one or more processors.

Thus, by way of example, an element may comprise components and processes such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, Microcode, circuitry, data, databases, data structures, tables, arrays, and variables, as will be appreciated by those skilled in the art.

The components and functions provided within those components may be combined into a smaller number of components or further separated into additional components.

An embodiment of the present invention may also be embodied in the form of a storage medium including instructions executable by a computer, such as program modules, being executed by a computer. Computer readable media can be any available media that can be accessed by a computer and includes both volatile and nonvolatile media, removable and non-removable media. In addition, the computer-readable medium may include both computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Communication media typically includes any information delivery media, including computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave, or other transport mechanism.

The control method according to the present invention can be implemented as a computer-readable code on a computer-readable storage medium. Computer-readable storage media include any type of storage medium that stores data that can be decrypted by a computer system. For example, there may be a ROM (Read Only Memory), a RAM (Random Access Memory), a magnetic tape, a magnetic disk, a flash memory, an optical data storage device and the like. In addition, the computer-readable storage medium may be distributed and executed in a distributed manner in a computer system connected to a computer network and readable in a distributed manner.

While the apparatus and method of the present invention has been described in connection with specific embodiments, some or all of those elements or operations may be implemented using a computer system having a general purpose hardware architecture.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

S1310: Timer Timeout
S1110: Receiving a packet
S1120: Update neighbor node information
S1130: Active neighbor node state update
S1140: Update node status
S1210: Request to send a packet
S1230: Active neighbor node state update
S1240: Update node status

Claims (10)

In a node included in an ad hoc network,
A storage unit storing a node table including information on the number of active neighbor nodes, and status information of the node;
A transmitting and receiving unit receiving a packet from a neighboring node or transmitting a packet to a neighboring node; And
And a controller for comparing the number of active neighbor nodes with a predetermined threshold value and setting the state of the node as active or passive according to a result of the comparison,
Wherein,
Generating a random number between zero and the number of active neighbor nodes if the number of active neighbor nodes is greater than or equal to the threshold,
Setting the node state to passive if the random number is greater than or equal to the threshold,
Setting the node state to active if the random number is less than the threshold,
And sets the state of the node to active if the number of active neighbor nodes is less than the threshold.
The method according to claim 1,
Wherein the node table further comprises an entry storing active neighbor node information,
Wherein,
When the receiving unit receives a packet from a neighboring node,
Checking whether information on the neighboring node is stored in the entry,
Updating the neighbor node information of the entry if information on the neighbor node is stored in the entry,
Generating a new entry if the information for the neighboring node is not stored in the entry, adding the neighboring node information to the entry, and increasing the number of active neighboring nodes.
3. The method of claim 2,
Wherein the active neighbor node information comprises:
Address information of an active neighbor node, and time information of a time at which a packet was last received from the active neighbor node,
Wherein,
When the address of the neighboring node that transmitted the packet is stored in the entry, updates the time information of the entry to the time of receiving the packet of the neighboring node,
Generating a new entry when an address of a neighboring node that has transmitted the packet is not stored in the entry, generating an address of a neighboring node that has transmitted the packet in the address information and time information, And increases the number of active neighbor nodes of the table.
The method according to claim 1,
Wherein,
And when the node makes a packet transmission request in an active state, approves transmission of the packet.
The method according to claim 1,
Wherein the node table further comprises an entry storing active neighbor node information,
Wherein,
Check for expired entries,
And if there is an expired entry, delete the expired entry and reduce the number of active neighbor nodes.
A method for controlling a state of a node included in an ad hoc network,
Wherein the node stores a node table including the number of active neighbor nodes and state information of the node,
Comparing the number of active neighbor nodes with a predetermined threshold value; And
And setting the state of the node to active or passive according to a comparison result of the comparing step,
Wherein the setting step comprises:
If the number of active neighbor nodes is greater than or equal to the threshold,
Generating a random number between 0 and the number of active neighbor nodes,
Comparing the random number and the size of the threshold value,
Setting the state of the node to active if the random number is less than a threshold,
Setting the status of the node to passive if the random number is greater than or equal to a threshold,
And setting the state of the node to active if the number of the active neighbor nodes is smaller than the threshold value.
The method according to claim 6,
Wherein the node table further comprises an entry storing information about an active neighbor node,
Wherein the active neighbor node information comprises:
Address information of an active neighbor node, and time information of a time at which a packet was last received from the active neighbor node,
When a node receives a packet from a neighboring node,
Prior to comparing the number of active neighbor nodes with the size of the threshold,
When the address of the neighboring node that transmitted the packet is stored in the address information, updates the time information of the entry to the time of receiving the packet of the neighboring node,
When an address of a neighboring node that has transmitted the packet is not stored in the address information, a new entry is generated and the address of the neighboring node that has transmitted the packet to the address information and the time information of the entry, And increasing the number of active neighbor nodes of the table.
The method according to claim 6,
And accepting transmission of the packet if the node requests a packet transmission in an active state.
The method according to claim 6,
Checking whether there is an expired entry; And
Deleting the expired entry if there is an expired entry, and decreasing the number of active neighbor nodes.
The method according to claim 6,
Initializing the number of active neighbors and a timer and setting the state of the node to an active state when a predetermined time has elapsed in a timer that operates when the node boots or there is no transmission or reception of a packet, ,
Further comprising the step of deleting all of the entries if a preset time has arrived in the timer,
Wherein the timer is present in the table, the node or an external device.

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