WO2014058229A1

WO2014058229A1 - Device and method for managing topology of mobile ad hoc network

Info

Publication number: WO2014058229A1
Application number: PCT/KR2013/009025
Authority: WO
Inventors: 윤석훈; 르반둑
Original assignee: 울산대학교 산학협력단
Priority date: 2012-10-12
Filing date: 2013-10-10
Publication date: 2014-04-17
Also published as: KR101413856B1; KR20140047340A

Abstract

The present invention relates to a device and method for managing the topology of a mobile ad hoc network. The present invention includes: a source node transmitting packet data; a destination node receiving the packet data; at least one relay node located on a transmission link between the source node and the destination node and transmitting the packet data; a plurality of link nodes connecting each node and configuring the transmission link; and one or more automatic units that move a link node having the lowest individual data transmission rate from among the link nodes in response to a request from a relay node or a destination node and that adds a link node, when the overall data transmission rate of the transmission link is lower than or equal to a preset reference data transmission rate. In addition, the present invention adds at least one automatic unit functioning as a mobile relay to a link node of which each PDR is lowest from among the link nodes between the source node and the destination node, or the present invention removes the at least one automatic unit therefrom. According to the present invention, since it is possible to constantly maintain data transmission quality between nodes, there is an advantage in that the transmission link quality between the source node and the destination node is maintained at a level equal to or higher than a reference value desired by a user.

Description

Topology management device and method for mobile ad hoc network

The present invention relates to an ad hoc network, and more particularly, each node by moving, placing or excluding an unmanned unit (unmanned robot, drone) based repeater on an individual link node on a transmission link in an ad hoc network. The present invention relates to a topology management apparatus and method for a mobile ad hoc network, which enables to maintain a constant data transmission quality.

Mobile ad hoc network (MANET) refers to an autonomous network in which nodes communicate with each other without a separate infrastructure for communication in terms of network configuration. In this network structure, since there is no node controlling in the middle, each node must communicate in the network by making the most of the information it can have, and communicate with other nodes through the other nodes for communication with a long distance node.

That is, the mobile ad hoc network can configure the network autonomously without the help of a central communication network or central control, and thus has an advantage that it can be usefully applied to natural disasters, search and rescue activities in the remote areas, and the like. In addition, since various topologies are configured through communication between nodes, the distance limitation of wireless network communication may be overcome.

In this mobile ad hoc network, several ad hoc routing protocols have been proposed for efficient data relay and routing. Examples of ad hoc routing protocols include AODV, DSR, OLSR, and the like. Adhoc On Demand Distance Vector (AODV) is a reactive routing protocol that allows routes to be reconfigured according to the needs of the source node. Dynamic Source Routing (DSR) is a protocol that newly establishes a data relay path according to a change in routing to a source node. OLSR (Optimized Link State Routing Protocol) is also a leading link-state routing protocol that uses propagation of link state over mobile ad-hoc networks. In this OLSR protocol, nodes use the shortest hop as the forwarding pace and use topology information to maintain the relay link of the mobile ad hoc network.

The mobile ad hoc network presented above serves to substantially route the optimized data in the distributed arrangement of nodes and network topology for the nodes to form a radio link.

However, even with these advantages, mobile ad hoc networks are still limited in their utility. For example, in terms of usability, the transfer speed between nodes in a mobile ad hoc network must continuously provide the high data transfer performance required by the user application, which is often not the case for various reasons. In other words, high mobility of nodes, radio channel quality that changes with time, geographic problems such as obstacles, and distributed in large areas may not provide the data transmission rate of the user's desired quality when the distance between nodes becomes far. Can be.

Therefore, even if a mobile node is distributed in a large area or there is a geographic problem such as an obstacle, it is necessary to maintain a constant data transmission quality between each node constituting the network topology.

Accordingly, an object of the present invention is to solve the above problems, and transmits data between nodes by selecting at least one unmanned transmission link among a plurality of links and moving at least one unmanned unit on the link to serve as a mobile repeater. The present invention provides a topology management apparatus and method for a mobile ad hoc network that maintains a certain level of quality.

Another object of the present invention is to optimize the position of the unmanned unit moving on the link to improve the performance of the data transmission relay, and the position of the relay node located between the source node and the destination node and between the source node and the destination node In case of fluctuation, the unmanned unit also moves with reference to the fluctuating position.

It is still another object of the present invention to constantly check the transmission rate of the link and to remove the unmanned unit on the link or stop the function as a mobile repeater when the function of the unmanned unit in the link is limited.

According to a feature of the present invention for achieving the above object, a source node for transmitting packet data; A destination node for receiving the packet data; At least one relay node located on a transmission link forming between said source node and a destination node for carrying said packet data; A plurality of link nodes connecting each node to each other and constituting the transmission link; And at least one unmanned unit that moves to a link node having the lowest individual link quality among the link nodes and adds a link node when the total data rate is less than or equal to a preset reference data rate. It provides a topology management device of an ad hoc network.

The mobile ad hoc network topology management apparatus further includes a control center for moving the unmanned unit located within its transmission range onto the link node when the unmanned unit does not exist within the message transmission range of the relay node or the destination node. .

The individual link quality includes a data transmission success rate (PDR), an expected transmission count (ETX), an expected transmission time (ETT), a weighted cumulative ETT (WCETT), and a packet loss rate of each link. (Loss Rate) and one or more of received signal strength (RSSI) are used.

In addition, the unmanned unit is configured by adding at least one to at least one link node of the link node according to the comparison of the total data rate of the transmission link and the preset reference data rate, and corresponds to the movement of the node connected to it You move your position.

According to another aspect of the present invention, in an ad hoc network structure consisting of a source node, one or more relay nodes, and a destination node, a receiving step of receiving, by the destination node, an individual data rate of a link node connecting each node; Calculating, by the destination node, the total data rate of the transmission link using the respective data rate; Comparing a total data rate of the transmission link with a preset reference data rate; And setting the at least one unmanned unit on the link node having the lowest data rate among the link nodes when the total data rate is less than or equal to the reference data rate. A topology management method is provided.

The setting may include: transmitting, by the destination node, a request message to a node requiring an unmanned unit; The node forwarding a response message to the destination node; And transmitting, by the node, a mobile message to an unmanned unit located within its message transmission range.

Here, the individual data rate may be provided by calculating the total data rate of the transmission link using a serial number of packet data transmitted from the source node to the destination node.

In addition, when the destination node has not received the response message, the request message is transmitted to an adjacent node so that the unmanned unit moves on the link node having the next lowest data rate.

And, if the total data rate of the transmission link is equal to or greater than the reference data rate, the unmanned unit provided in the setting step is kept in position.

And, if the data rate of the transmission link including the unmanned unit is less than or equal to the data rate of the transmission link without the unmanned unit, characterized in that to remove the unmanned unit located on the link node.

In addition, when the unmanned unit is located on a link node, the unmanned unit moves to be located at an intermediate point between nodes connecting the link nodes using at least one of a location information value, an RSSI value, and an SNR value using GPS. It features.

On the other hand, if there is no unmanned unit around the relay node and the destination node, the node required by the unmanned unit transmits a request message to the control center using a wireless channel, the control center to the unmanned unit available state By transmitting a mobile message, it is characterized in that the unmanned unit is moved on the link node.

According to the topology management apparatus and method of the mobile ad-hoc network of the present invention, in the multi-hop wireless relay link structure, one or more unmanned units, which serve as relays, can be autonomously moved to link nodes having low individual data rates. As a result, the data transmission quality between nodes can be kept constant.

This ensures that the quality of the transmission link between the source and destination nodes is always maintained above the user's desired threshold.

1 is an overall configuration diagram of a mobile ad hoc network provided to explain an embodiment of the present invention;

2 is a configuration diagram showing an example in which an unmanned unit is added to the mobile ad hoc network shown in FIG.

3 is a flowchart illustrating a process of moving and adding an unmanned unit to a link node of FIG. 2 and a process of removing an unmanned unit.

4 is an exemplary view illustrating a configuration in which an unmanned unit moves to a link node by a control center according to another embodiment of the present invention.

5 is an exemplary view illustrating a process of arranging and removing an unmanned unit according to a position change of a node and an unmanned unit according to the present invention.

Hereinafter, embodiments of an apparatus and method for managing a topology of a mobile ad hoc network according to the present invention will be described in detail with reference to the accompanying drawings.

1 is an overall configuration diagram of a mobile ad hoc network provided to explain an embodiment of the present invention. As shown in FIG. 1, a mobile ad hoc network (hereinafter referred to as an 'ad hoc network') 100 includes

nodes

101 and 102 and a plurality of

unmanned units

110, 120, 130, and 140. do.

Nodes

101 and 102 are composed of at least two. A normal node is a medium for transmitting and receiving packet data. In FIG. 1, reference numeral '101' is used as a source node, and '102' is classified as a destination node. In some cases, at least one relay node may be provided between the source node 101 and the destination node 102. The relay node serves to deliver the packet data transmitted from the source node 101 to the destination node 102. Of course, if the source node 101 can deliver packet data to the destination node 102 without the assistance of the relay node, the relay node is not necessarily required. On the other hand, when the source node 101 needs to reach the destination node 102 through several hops of the packet data, the relay node is necessary.

The source node 101 and the destination node 102 have a message including their ID and location information, which are broadcast periodically or randomly to their surroundings.

The

unmanned units

110, 120, 130, and 140 are located between the source node 101 and the destination node 102 to serve as mobile repeaters as necessary. Unmanned

unit

110, 120, 130, 140 also has a message including its ID and location information. The unmanned unit will be described in more detail with reference to FIG. 2.

According to FIG. 1, the source node 101 and the destination node 102 are provided with a message including their ID and location information from the

unmanned units

110, 120, 130, and 140. Location information for the 120, 130, and 140 may be obtained. In addition, the source node 101 and the destination node 102 may also send and receive messages to each other to check the location information of the other party. In addition, since the messages transmitted and received by the source node 101 and the destination node 102 also include messages for the

unmanned units

110, 120, 130, and 140, the source node 101 or the destination node ( 102 may also check the information on the unmanned unit that is outside the transmission range. For example, the source node 101 can know the location information of the unmanned unit (130, 140).

FIG. 2 is a diagram illustrating an example in which an unmanned unit is added to the mobile ad hoc network illustrated in FIG. 1.

Referring to FIG. 2, a source node 210 and a destination node 250 are configured.

Relay nodes

220, 230, and 240 are configured between the source node 210 and the destination node 250. As described above, the source node 210, the

relay node

220, 230, 240, and the destination node 250 have a message including their ID and location information.

The transmission path between the source node 210 and the destination node 250 generally consists of multiple hops. Therefore, when the source node 210 delivers the packet data to the destination node 250, an independent link exists between the nodes due to the

relay nodes

220, 230, and 240, and a combination of the respective links. Packet data is passed through. Therefore, in the embodiment, a link formed between the node and the node will be described as a 'link node', and all of the link nodes, that is, the entire transmission path will be described as a 'transport link'.

Accordingly, in FIG. 2, link nodes may be represented by '11', '12', '13', and '14' by reference numerals, and transmission links representing the entirety of these link nodes may be represented by '10'. .

Each node that serves to receive packet data transmitted by the source node 210, that is, the

relay nodes

220, 230, and 240, and the destination node 250 are each

link node

11, 12, 13, and 14. Each individual packet delivery ratio ( PDR ) for each PRS can be measured. Each

relay node

220, 230, 240 transmits the individual data rates ( each PDR ) for the

link nodes

11, 12, 13, and 14 measured by the

relay nodes

220, 230, and 240 to adjacent nodes located in the transmission path direction. do. In particular, the destination node 250 measures an individual data rate ( each PDR ) for the link node 14 connected to the destination node 250, and periodically uses the serial number included in the packet data to periodically check the source node 210 and the destination node ( 250), the total data rate (PDR on all transmission links 10 to: a _ete R) is measured. Here, the data rate refers to a data delivery rate (PDR), which will be briefly described as a data rate in the embodiment.

At least one unmanned unit 300 is constructed which moves on the

link nodes

11, 12, 13, 14 to serve as mobile repeaters. The unmanned unit 300 refers to robotic nodes (RN). The unmanned unit 300 also serves as one node capable of transmitting and receiving data, and moves autonomously according to a series of control operations. The unmanned unit 300 is installed in the air above the ground, and underwater according to the location or location of the ad hoc network.

Next, a process of newly configuring a transmission link by moving an unmanned unit on a link node in the mobile ad hoc network structure of FIG. 2 will be described with reference to FIG. 3. 3 is a flowchart illustrating a process of moving and adding an unmanned unit to a link node of FIG. 2 and a process of removing an unmanned unit.

First, packet data is transmitted from the source node 210 (s100). The generated packet data is transferred to the destination node 250 which is the final destination via the

relay nodes

220, 230 and 240 (s102).

During the transmission of the packet data, each of the

relay nodes

220, 230, 240, and the destination node 250 receives packet data from the previous node and transmits the packet data to each

link node

11, 12, 13, 14. The individual data rate for each PDR is measured (s104). The measured individual data rate each PDR is transmitted to the destination node 250 together with the packet data (s106).

The destination node 250 may determine the link node required by the unmanned unit through each received data rate ( PDR ) or serial number of packet data.

To this end, the destination node 250 first calculates the total data rate ( All PDR : _Rete ) for the transmission link 10 by using Equation 1 below. [Equation 1] is an example using the serial number of the packet data. That is, the total data rate ( all PDR : _Rete ) is measured as a ratio of the number of packets received by the destination node 250 and the number of packets transmitted by the source node 210 during a predetermined time interval. The serial number is included in the packet data to cause the destination node 250 to determine the number of transmitted packets and the number of lost packets.

Equation 1

The destination node 250 is the total data rate by Equation 1: Calculate the (R _ete all PDR) and compares it with the set group based on the data rate (s108). For reference, the reference data rate may be a value set by a user or a network administrator or a minimum value at which packet data may be smoothly transmitted in an ad hoc network. However, the reference data rate may be changed by various topographic factors such as spaces and obstacles in which nodes are arranged.

As a result of comparing the total data rate ( All PDR : _Rete ) and the reference data rate, when the total data rate ( all PDR : _Rete ) is less than the reference data rate (s110), the destination node 250 is a link node 11 12, 13, and 14 determine the link node having the smallest individual data rate ( each PDR ) (s112). Here, the determination of the link node having the smallest individual data rate ( each PDR ), the destination node 250 periodically measures the packet transmission success rate using the serial number included in the packet data, the packet transmission success rate does not meet the criteria The failed link node may be determined to have the lowest link quality. In FIG. 2 of the embodiment, it is assumed that the link node having the smallest individual data rate ( each PDR ) is '13'. This is a link node connecting the relay node 230 and the relay node 240.

Accordingly, the destination node 250 transmits a request message (REI-REQ) for adding an unmanned unit to the relay node 240 on the link node 13 (s114).

The relay node 240 receiving the request message REI-REQ transmits a response message ACK to the destination node 250 (s116). At the same time, the relay node 240 determines whether there is an unmanned unit within a range, for example, in one hop or two hops (S118). As a result of the determination, if there is an unmanned unit 300, a mobile message MREQ is transmitted to the unmanned unit 300 (S120). Here, if the destination node 250 does not receive any response message (ACK) from the relay node 240 after the transmission of the request message (REI-REQ), the individual data rate ( each PDR ) is the next smaller link Send a request message (REI-REQ) to the relay node associated with the node. This process proceeds sequentially and repeatedly depending on whether or not a response message (ACK) is received. On the other hand, if the unmanned unit does not exist as a result of the determination in step 118 is configured to search for and add the unmanned unit by the control center to be described later (s132). The function performed by the control center will be described with reference to FIG. 4.

The unmanned unit 30 receiving the movement message MREQ moves on the link node 13 (s122), where the unmanned unit 300 is located at an intermediate point of the link node 13. desirable. This is to efficiently transmit packet data between the relay node 230 and the relay node 240. Here, the operation of moving the unmanned unit 300 to the intermediate point of the link node 13 will be described in detail below.

When the unmanned unit 300 moves to the intermediate point on the link node 13 according to the above process, the link node 13 is connected to the link node 13 'and the link node 13 "by the unmanned unit 300. In this case, the unmanned unit 300 notifies that the transmission path has been changed by transmitting a link change message (CHG-NEXT-HOP) to the relay node 230. In addition, the relay node 240 sends a response message ( REI-REP) is transmitted to the destination node 250 to confirm that the unmanned unit 300 has been added normally.

According to the above-described process, the unmanned unit 300 additionally disposed at the link node 13 among the

link nodes

11, 12, 13, and 14 performs a role as a mobile repeater (S124). Therefore, the relay node 230 and the relay node 240 and increase the transmission rate of the packet data in between, whereby the total data rate of the transmission link (10) can be improved (all R _ete PDR).

The destination node 250 has full data rate of the transmission link 10 after the link node (13 ') (13 "), the newly formed: Measure (all PDR R _ete) (s126) The results of the measurements are as described above total data rate due to the additional arrangement of the unmanned unit 300 as: not less than (all PDR R _ete) the standard data rate is (s128), maintains the current transmission link status (s130), while unattended unit ( 300) is added batch though the overall data rate (all PDR: when R _ete) the standard data rate or less should not stop, go to the 114 steps as described above is performed by repeating the process of adding an unattended unit 300 This may continue to be performed until the total data rate ( All PDR : _Rete ) is greater than or equal to the reference data rate.

On the other hand, it is necessary to remove the unmanned unit 300 in a state where the unmanned unit 300 is disposed in the

link nodes

11, 12, 13, 14. That is, even if the unmanned unit 300 is added, if the total data rate ( all PDR : _Rete ) for the transmission link 10 before the unmanned unit 300 is added does not increase, in this case, the unmanned unit 300 is removed. can do.

Next, a description will be given of how the unmanned unit 300 moves to the intermediate point of the link node 13. The method for moving to the intermediate point is presented in three embodiments in the embodiment.

Firstly, the GPS information is used to move to the midpoint of the geographic location.

In this method, the unmanned unit equipped with the GPS receiver module checks the midpoint between the nodes based on its position and the position of the nodes (i.e., the transmitting node, the relay node, and the destination node) acquired through the GPS signal, and the tolerance range. To go inside. After the unmanned unit is moved to the midpoint between the nodes, a process of relocating the location is performed at predetermined time periods.

The second method is to move to the midpoint using RSSI.

This method first parallelizes the method of moving to the midpoint of the geographical location. That is, the unmanned unit moves to the midpoint of the geographical position between nodes. The unmanned unit then compares the RSSI values between nodes and moves to a point where the RSSI values are equal or within tolerance. The unmanned unit will then move on a line segment that connects the nodes.

Third, the method moves to the midpoint using the SNR value.

This also parallels the way to the midpoint of the geographic location. That is, the unmanned unit moves to the midpoint of the geographic location between the nodes. The unmanned unit then compares each SNR value with the node and moves to a point where the SNR values are equal or within tolerance. The unmanned unit will then move on a line segment that connects the nodes.

Meanwhile, as described above, the process related to the movement of the unmanned unit is performed by the corresponding node (that is, the relay node) receiving the request message (REI-REQ) of the destination node and delivering the movement message (MREQ) to the unmanned unit. Is done. However, this case is limited to the case where there is an unmanned unit within a certain range in which a node can transmit a message, that is, 1 to 2 hops. If there is no unmanned unit within the above-described predetermined range, the operation of moving the unmanned unit to a link node having a low data rate cannot be performed. However, even if there is no unmanned unit within a certain range to move the unmanned unit to improve the data transmission quality of the transmission link. This will be described with reference to FIG. 4.

As shown in FIG. 4, the source node 400, the destination node 404, the

relay nodes

401, 402, 403 and the transport nodes forming the transport link between the source node 400 and the destination node 404. It includes an unmanned unit 410 to serve as a repeater. At this time, the unmanned unit 410 is a case where the source node 400, the relay node 401 (402) 403, the destination node 404 is located outside the range that can send a message.

In addition, the control center 420 is further configured. The control center 420 may be a central management center or a base station. The control center 420 receives a request message (RN-REQ) for adding an unmanned unit 410 at a specific node and transmits a mobile message (MREQ) to an unmanned unit 410 in an available state. . At this time, the unmanned unit 410 in the available state is in a waiting state for deployment or within the transmission range of the control center 420, for example, the unmanned units are located within 1 to 2 hops.

In this configuration will be described the process of moving the unmanned unit.

4, the first to

third relay nodes

401, 402, 9403 are located between the source node 400 and the destination node 404, and a total of four

link nodes

21, 22, and 23 are located. 24 is present. It is assumed that the individual data rates ( each PDR ) of the second link node 22 among the

link nodes

21, 22, 23, and 24 are the lowest.

In this state, since the unmanned unit is not located around the second relay node 402, the second relay node 402 uses a long distance low-speed radio channel to place the unmanned unit on the second link node 22. The request message RN-REQ is transmitted to the control center 420.

Then, the control center 420 searches for an unmanned unit in an available state in which it maintains information according to the request message RN-REQ. If there is an unmanned unit 410 in an available state around the search result control center 420, a mobile message (MREQ) is transmitted to the unmanned unit 410.

When the unmanned unit 410 receives the mobile message MREQ, the unmanned unit 410 moves to the intermediate point between the first relay node 401 and the second relay node 402 to form a new link node, and the packet is transmitted through the unmanned unit 410. Allows data to be passed Here, the process of moving to an intermediate point or forming a new link node will be applied as described above.

5 is an exemplary view illustrating a process of disposing and removing an unmanned unit according to a change in position of a node and an unmanned unit according to the present invention.

5 illustrates a process of disposing a node and an unmanned unit in consideration of time.

First, in the initial 't1' time zone, the source node 510, the first relay node 520, the second relay node 530, the destination node 540, and the second unmanned unit 620 form a transport link. have. The first unmanned unit 610 is not included in the transmission link in the 't1' time zone.

Thereafter, the source node 510, the first relay node 520, the second relay node 530, and the destination node 540 correspond to the source node 511, the first relay node 521, and the corresponding time lapse. The second relay node 531 is moved to the destination node 541. The nodes move to perform functions such as collecting information as needed. At this time, the movement of the unmanned unit 620 according to the movement of the nodes should also be considered.

That is, the source node 511 and the first relay node (t2) in the state where the position is changed to the source node 511, the first relay node 521, the second relay node 531, and the destination node 541 at 't2'. The first unmanned unit 610 moves on the link node when the individual data rates ( each PDR ) of the link nodes formed between 520 are the lowest. Also, if the respective data rate ( each PDR ) between the first relay node 520 and the second relay node 530 is not improved, the second unmanned unit 620 is also located on the link node as in the 't1' time. However, at this time, based on the changed position information of the first relay node 520 and the second relay node 530 is moved.

In the next 't3' it can be seen that the position changed to the source node 512, the first relay node 522 and the second relay node 532, the destination node 542 compared to the 't2'. And as can be seen in the figure between the source node 512 and the first relay node 522 is close, while the first relay node 522 and the second relay node 532, and the second relay node 532 and It can be seen that the destination nodes 542 are further away. In this case, since the individual data rates ( each PDR ) and the total data rates ( all PDR : _Rete ) for the link nodes between nodes are measured at all times, the arrangement of the unmanned unit should also be changed according to comparison with the reference data rate.

Therefore, if the source node 512 and the first relay node 522 are close to each other , and the individual data rate ( each PDR ) and the total data rate ( all PDR : R _ete ) are improved, they are placed in the link node in the 't2' time zone. The unmanned unit 610 is preferably removed. That is, as shown in the figure, the unmanned unit 6120 is removed between the source node 512 and the first relay node 522. On the contrary, since the first relay node 522 and the second relay node 532 and the second relay node 532 and the destination node 542 are further apart, it is preferable that an unmanned unit is further disposed. Accordingly, it can be seen that the first unmanned unit 610 is added between the first relay node 522 and the second relay node 532 in addition to the second unmanned unit 620 that is previously disposed. The same applies to the second relay node 532 and the destination node 542. That is, it can be seen that the third unmanned unit 631 is further configured between the second relay node 532 and the destination node 542.

As shown in FIG. 5, even though nodes move in the initially configured ad hoc network, the unmanned unit moves with the nodes, and thus the transport link for transmitting packet data is continuously maintained. This node and unmanned unit is the other node and to determine the location of the unmanned units and well as the individual data rate for each link node (each PDR) and the total data rate of the transmitted Link is also possible to check (all R _ete PDR).

As described above, in an embodiment of the present invention, at least one unmanned station serving as a mobile relay to a link node having the lowest individual data rate ( each PDR ) among a plurality of link nodes existing between the source node and the destination node. As the process of adding or removing units establishes various transmission links, it can be seen that data transmission quality between nodes can be kept constant at all times.

Meanwhile, in the above-described exemplary embodiment, the unmanned unit is limited to moving to the link node having the lowest data rate by determining the data rate. However, the unmanned unit moves by comparing the link quality of the link node in addition to the data rate. The configuration can also be applied to the present invention. In other words, the estimated transmission count (ETX: Expected Transmission Count), expected transmission time (ETT: Expected Transmission Time), WCETT (weighted cumulative ETT), packet loss rate (RSSI), etc. It is also possible to use more than one.

Although described with reference to the illustrated embodiment of the present invention as described above, this is merely exemplary, those skilled in the art to which the present invention pertains without departing from the spirit and scope of the invention It will be apparent that other variations, modifications and equivalents are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

The present invention selects a weak link among multi-hop links from a data source to a destination, and moves the autonomous drone to an optimal position for relaying to form a high quality wireless link to replace the selected link. Because it can play a role, it is expected that the user can provide a data transmission rate of a desired quality, so that it can be applied to various fields such as civil and military purposes when there is no backbone network or limited function.

Claims

A source node for transmitting packet data;

A destination node for receiving the packet data;

At least one relay node located on a transmission link forming between said source node and a destination node for carrying said packet data;

A plurality of link nodes connecting each node to each other and constituting the transmission link; And

Mobile ad hoc including one or more unmanned units that move to the link node having the lowest individual link quality among the link nodes and add the link node when the total data rate is less than or equal to the preset reference data rate. Topology management unit in the network.
The method of claim 1,

When the unmanned unit does not exist in the message transmission range of the relay node or the destination node, a control center for moving the unmanned unit located within its transmission range on the link node, the topology management apparatus of the mobile ad hoc network .
The method according to claim 1 or 2,

The individual link quality includes a data transmission success rate (PDR), an expected transmission count (ETX), an expected transmission time (ETT), a weighted cumulative ETT (WCETT), and a packet loss rate of each link. Topology management device of a mobile ad hoc network, characterized in that at least one of (Loss Rate), received signal strength (RSSI) is used.
The method according to claim 1 or 2,

The unmanned unit is configured by adding at least one to at least one link node of the link nodes according to a comparison of the total data rate of the transmission link with a preset reference data rate, and corresponding to the movement of the node to which it is connected. Topology management device of a mobile ad hoc network, characterized in that to move the location of.
In an ad hoc network structure consisting of a source node, one or more relay nodes, and a destination node, the receiving step of receiving, by the destination node, an individual data rate of a link node connecting each node;

Calculating, by the destination node, the total data rate of the transmission link using the respective data rate;

Comparing a total data rate of the transmission link with a preset reference data rate; And

And comparing the at least one unmanned unit on the link node having the lowest data rate among the link nodes if the total data rate is less than or equal to the reference data rate. Topology management method.
The method of claim 5, wherein the setting step,

Transmitting, by the destination node, a request message to a node requiring an unmanned unit;

The node forwarding a response message to the destination node; And

And transmitting, by the node, a mobile message to an unmanned unit located within its message transmission range.
The method according to claim 5 or 6,

And said individual data rate calculates the total data rate of said transmission link using a serial number of packet data transmitted from said source node to said destination node.
The method of claim 6,

If the destination node has not received the response message, the topology management method of the mobile ad hoc network, characterized in that the request node is retransmitted to the adjacent node so that the unmanned unit moves on the link node with the next lowest data transmission rate of the link node. .
The method of claim 5,

And if the total data rate of the transmission link is equal to or greater than the reference data rate, maintaining the unmanned unit provided in the setting step.
The method of claim 5,

And if the data rate of the transmission link including the unmanned unit is less than or equal to the data rate of the transmission link without the unmanned unit, removing the unmanned unit located on the link node.
The method of claim 5,

When the unmanned unit is located on a link node, the unmanned unit moves to be located at an intermediate point between nodes connecting the link nodes using at least one of a location information value, an RSSI value, and an SNR value using GPS. Topology management method of mobile ad hoc network.
The method of claim 5,

If there is no unmanned unit around the relay node and the destination node, the node required by the unmanned unit transmits a request message to the control center using a wireless channel, and the control center moves a message to the unmanned unit in an available state. The method for managing a topology of a mobile ad hoc network, characterized in that for transmitting the unmanned unit is moved on the link node.