KR102211796B1 - Method for controlling message communication in Ad hoc On-demand Distance Vector and System thereof - Google Patents

Abstract

According to one embodiment of the present invention, disclosed is a method for ensuring a high packet transmission rate by establishing a more stable path compared to the existing AODV, by adding a first parameter, a second parameter, and a third parameter to a header of a message transmitted and received in an AODV network.

Description

AODV network message transmission/reception control method and system thereof {Method for controlling message communication in Ad hoc On-demand Distance Vector and System thereof}

The present invention relates to an AODV network message transmission/reception control method and system thereof. More specifically, a first parameter, a second parameter, and a third parameter according to a preset reference time are added to a header of a message received on an AODV network. By doing so, the present invention relates to a method and a system for ensuring a high packet transmission rate by establishing a more stable path compared to the existing AODV.

An ad hoc network refers to a network in which a topology is autonomously configured by a plurality of nodes in an environment where there is no infrastructure of a specific network. Ad hoc network routing protocols can be classified into proactive, reactive, and hybrid methods according to a method of configuring a routing path.

The proactive method is characterized in that each node constituting the network periodically exchanges routing information through a routing table. The proactive method has an advantage in an environment with low latency and a small number of nodes when setting a route because all nodes know the routing information of other nodes, while there is a disadvantage in that the network load increases to maintain the routing information.

Unlike the proactive method, the reactive method establishes a path only when there is a message delivery request from a specific node. While the reactive method has a lower network load than the proactive method and has an advantage in a network environment where nodes are frequently moved, it takes a long time to set up a route compared to the proactive method, and a control message is transmitted for the route setting. As a result, there is a disadvantage that the network load increases.

In the hybrid method, a proactive method and a reactive method are used at the same time, and a network topology is formed between nodes with low mobility through the proactive method, and paths are established between nodes with high mobility through the reactive method. It has some of the advantages and disadvantages of the pro-act method and the reactive method.

According to the Ad-hoc On-Demand Distance Vector (AODV) routing algorithm, which is a representative reactive method, the source node uses RREQ (RREQ) to obtain route information for the destination node. Route REQuest) message is broadcast, and each node that receives it sends a RREP (Route REPly) message back to the reverse route to which the RREQ message was delivered, if it has information about the destination. Broadcast. When the RREQ message is delivered to the destination node, the destination node delivers the RREP message to the source node along the reverse path where the RREQ message was delivered. When the RREP message arrives at the source node, a bidirectional path is established between the source node and the destination node. The source node delivers the destination message to the destination node through the set path. In the process of delivering a message through the established path, the node that detects the disconnection of the path sends a RERR (Route Error) message to the source node to notify the path disconnection and search for a new path, or find a new path from the disconnected intermediate node. Local repair methods can also be used.

As above, AODV currently uses only the shortest hops as a metric for routing. In addition, the reliability of path problem caused by using the shortest hop as a metric has been pointed out by experts in this field for a long time, and various studies have been conducted to solve this problem, but still reliability. A methodology for solving the problem clearly has not been proposed.

1. Korean Patent Registration No. 10-1174549 (published on September 08, 2011) 2. Korean Patent Registration No. 10-2027997 (announced on Oct. 4, 2019)

The technical problem to be solved by the present invention is an AODV network that continuously updates the optimal route by adding three parameters to the header of a message transmitted and received between nodes, analyzing the added parameter from the destination node, and repeating route setting. It is to provide a method for controlling message transmission and reception.

A method according to an embodiment of the present invention for solving the above technical problem is a method for controlling message transmission and reception of an ad hoc on-demand distance vector (AODV) network operating in a network environment consisting of a source node, a relay node, and a destination node. A request message transmitting step of controlling the source node to transmit a request message to a relay node adjacent to the source node if there is no active path from the source node to the destination node; A message for controlling at least one relay node that has received the request message to add the information of the received relay node to the header of the request message, and to transmit the request message to which the information is added to an adjacent relay node or destination node. Relay stage; And generating a response message based on the average value of the first parameter, second parameter, and third parameter included in the header of the request message, and transmits the response message to the source node by receiving the request message to which the information is added. And a controlling response message transmitting step, wherein the first parameter, the second parameter, and the third parameter are values according to a network environment that varies for each reference time.

A system according to another embodiment of the present invention for solving the above technical problem is a message transmission/reception control system of an ad hoc on-demand distance vector (AODV) network operating in a network environment consisting of a source node, a relay node, and a destination node. As, it includes a node management unit, a branch operation unit, and a repetition control unit, wherein the node management unit transmits a request message to a relay node adjacent to the source node when there is no active path from the source node to the destination node. Control, and at least one relay node that has received the request message adds the information of the received relay node to the header of the request message, and transmits the request message to which the information is added to an adjacent relay node or destination node. Control, the destination node receives the request message to which the information is added, and generates a response message based on the average value of the first parameter, the second parameter, and the third parameter included in the header of the request message to the source node. Control to transmit, and the branch operation unit performs an operation to transmit a request message or a response message to a relay node or a destination node adjacent to a node controlled by the node management unit, and the repetition control unit, the number of relay nodes The repetitive operation of the branch operation unit is controlled in proportion, and the first parameter, the second parameter, and the third parameter may be values according to a network environment that varies for each reference time.

An embodiment of the present invention may provide a computer-readable recording medium storing a program for executing the method.

According to the present invention, a more stable path is established compared to the existing AODV network scheme, thereby ensuring a high packet transmission rate.

In addition, according to the present invention, compared to the conventional AODV network method, it is possible to expect an effect of minimizing a delay rate due to packet retransmission.

1 is a diagram schematically showing an example of a network environment of a mobile ad hoc network.
2 shows a block diagram of an example of a system according to the present invention.
3 schematically shows the format of the request message of the present invention.
4 is a flowchart of an example of a method for controlling transmission and reception of an AODV network message according to the present invention.

Since the present invention can apply various transformations and have various embodiments, specific embodiments are illustrated in the drawings and will be described in detail in the detailed description. Effects and features of the present invention, and a method of achieving them will be apparent with reference to the embodiments described later in detail together with the drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various forms.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, and when describing with reference to the drawings, the same or corresponding components are assigned the same reference numerals, and redundant descriptions thereof will be omitted. .

In the following embodiments, terms such as first and second are used for the purpose of distinguishing one component from other components, not for a limiting meaning.

In the following embodiments, a singular expression includes a plurality of expressions unless the context clearly indicates otherwise.

In the following embodiments, the terms include or have means that the features or elements described in the specification are present, and do not preclude the possibility of adding one or more other features or components in advance.

When a certain embodiment can be implemented differently, a specific process order may be performed differently from the described order. For example, two processes described in succession may be performed substantially simultaneously, or may be performed in an order opposite to the described order.

1 is a diagram schematically showing an example of a mobile ad hoc network environment.

Referring to FIG. 1, it can be seen that the network environment of FIG. 1 includes a source node 11, an end node 13, and a destination node 15, and between the source node 11 and the destination node 15 Since a plurality of relay nodes are located in the source node 11, the message transmitted from the source node 11 to the destination node 15 is relayed.

In FIG. 1, each node is a node having mobility, and its geographic location is variable over time. The solid line and dotted line between the node and the node mean the connection based on MANET (Mobile Ad hoc Network), respectively.

That is, since the solid line between the node and the node is a connected link by MANET, the nodes connected by MANET transmit messages through a method of spreading RREQ, RERR, RREP, etc., and between nodes and nodes. The dotted line is a path that has not yet been established, but is a link that can be potentially established, and is between the source node 11 and the destination node 15 according to changes in the network environment depending on the passage of time or external factors. It can be used when there is a need to change the path of

In FIG. 1, the source node 11 generates a request message and a destination message for establishing a transmission path to the destination node 15. In addition, in FIG. 1, the end node 13 receives the request message generated by the source node 11, generates an error message, and transmits it to the source node 11 through the reverse path of the path of the request message. The destination node 15 receives a request message (RREQ) and a destination message from the source node 11, and generates a response message (RREP) to indicate that the request message has been received, so that the request message is sent to the source node 11 The response message is controlled to arrive at the source node 11 through a reverse path of the path transmitted to the node 15.

The attributes and characteristics of messages exchanged between the source node 11, the plurality of relay nodes, and the destination node 15 of FIG. 1 will be described later in FIG. 2. In addition, for convenience of explanation, in FIG. 1, the function of each node has been described with the source node 11, the end node 13, and the destination node 15 as subjects, but in reality, the source node 11 and the end node 13 ) And the operation of the destination node 15 are based on a protocol defined in the ad hoc network message transmission/reception control system that controls the network environment.

2 shows a block diagram of an example of a system according to the present invention.

Referring to FIG. 2, it can be seen that the system 100 for transmitting and receiving an AODV network message according to the present invention includes a node management unit 110, a branch operation unit 130, and a repetition control unit 150. Hereinafter, it is assumed that the network environment includes one source node, one destination node, and at least one relay node.

First, the node management unit 110 manages information of each node constituting the network. The node management unit 110 manages a routing table generated by each node constituting a network, and manages information so that an abnormality does not occur in a path set from a source node to a destination node.

As an example, the node management unit 110 may control the source node to transmit a request message (RREQ) to a relay node adjacent to the source node if there is no active path from the source node to the destination node. At this time, if there is an active path from the source node to the destination node, the source node may transmit the request message to the destination node through the already generated path or directly to the destination node in a unicast method.

In addition, the node management unit 110 adds the information of the relay node to the header of the request message by the relay node receiving the request message (RREQ) from the source node, and sends the request message to which the information is added to the adjacent relay node or It can be controlled to send to the destination node. As the request message passes through multiple relay nodes, more relay node information is included, and the information included in the request message is converted into a response message, and is finally used to determine the path at the source node. Information on the relay node included in the request message will be described later with reference to FIG. 3.

When the request message transmitted from the source node is transmitted to the destination node through at least one relay node, the node management unit 110 controls the destination node to generate a response message based on the request message. Specifically, when the destination node receives the request message, the node management unit 110 generates a response message based on the average value of the first parameter, the second parameter, and the third parameter included in the header of the request message and transmits it to the source node. To be controlled.

That is, in the present invention, the source node sets the path by additionally defining three parameters as multiple parameters in the response message required to determine the path, so that when a packet is transmitted through the configured path, a high packet rate can be guaranteed. I can. The three parameters included in the header of the request message have the following characteristics.

First, the first parameter may be defined as a value obtained by dividing a sum of links newly created between nodes constituting a network during a reference time and links released between nodes constituting a network during a reference time by a reference time. For example, based on the node currently under control of the node management unit 110 for a given time t, the sum of the number of new links (connections) established and the number of links (connections) disconnected is obtained, and at a given time t The divided value may be the first parameter. If the number of newly established links is 20 for 10 seconds and the number of disconnected links is 10, the first parameter may be 1 or 3. The number of disconnected links may be positive or negative depending on the setting. The first parameter may be referred to as a link change rate (LCR) as a rate of link change per unit time, and units/s may be used as the unit of the first parameter.

The second parameter may be defined as a value obtained by dividing the total amount of data in a buffer of a node constituting the network during the reference time by the reference time. The second parameter means the occupancy ratio of the buffer of the node, and is a value calculated as an average value of how much data exists in the buffer for a given time t.

time One 2 3 4 5 6 7 data 40 30 20 50 55 20 19

Table 1 is a table showing numerical values for explaining the method for obtaining the second parameter.

As shown in Table 1, the amount of data changed from 40 to 19 during the 7 unit time period, and based on Table 2, when the second parameter, which is the ratio that occupied the buffer of the node, is calculated, 32 is obtained. The second parameter is a numerical value indicating how much data occupies the buffer of a corresponding node per unit time, and may be referred to as BOR (Buffer Occupancy Ratio), and the unit may be byte/s.

The third parameter may be defined as a value obtained by dividing the sum of the intensity of signals received from each node constituting the network during the reference time by the reference time. Since the third parameter means an average value of the strength of the signal received by the node during a given time, it is possible to use dB/s (decibels per unit time) as a unit. The third parameter may be referred to as RSSI (Received Signal Strength Indicator).

The first parameter to the third parameter are calculated by the corresponding node each time a request message is transmitted, and are continuously averaged as history information of the request message. Since the first parameter to the third parameter are accumulated on average, the request message may be monotonically reduced or changed to a form in which a specific section is vibrated while the request message is continuously transmitted. The reference time for calculating the first parameter to the third parameter may be an arbitrary value and may be changed to an appropriate value by an administrator of the system.

When the request message arrives at the destination node, the node management unit 110 constructs several paths based on the multiple parameters included in the header of the request message, and the largest value The path to have is determined as the optimal path. In order to determine the optimal route at the destination node, as an example of a method of calculating the path value, the Analytic Hierarchy Process (AHP) and Simple Additive Weighting (SAW) can be used. have.

Equation 1 is an equation for calculating a path value.

In Equation 1, Vpath is the path value from the source node to the destination node, k1, k2, and k3 are weights for the first parameter, the second parameter, and the third parameter, and V1, V2, V3 are the first parameter, and It means the 2nd parameter and the 3rd parameter respectively. The weights of the three parameters are preset and may vary according to network fluctuations.

As an example, if the value representing the mobility of the network is higher than the preset mobility criterion a1 (if mobility is fast), the weight k1 of the first parameter (LCR) may be increased by one step (by 1), and the preset mobility If the criterion a2 is not reached (when network congestion occurs), the weight k2 of the second parameter BOR may be increased by one step (by 1). The mobility criterion is a variable value according to the number of paths constituting the path and the length of the path, and may be stored in advance as a reference value in the node management unit 110 or each node. In addition, the same method as the mobility criterion described above may be applied to the weight of the third parameter RSSI.

According to Equation 1, when two request messages are transmitted to the destination node and two paths A and B are confirmed, even if path A has a higher path value when multi-parameter weights are not applied, multi-parameter weighting When is applied, route B with a higher route value can be selected by the destination node.

Equation 2 is another example of calculating a path value, and may be used when an average value of three parameters is used.

As described above, according to the present invention, it is possible to calculate a route value from multiple parameters and establish a route by reflecting the mobility situation of the network, thereby ensuring a higher packet transmission rate compared to the existing AODV network method, and significantly increasing the time delay rate. Can be reduced.

In addition to the above-described methods, the hierarchical analysis method and the simple weighting method used in the present invention follow a widely known method, and thus a detailed description thereof will be omitted.

The node management unit 110 calculates at least two or more route values from the branch operation unit 130 when a plurality of routes can be set from the source node to the destination node according to the arrangement of nodes constituting the network and changes in the network environment. The destination node receives the required information and controls to calculate the route value through multiple parameters.

Through the above process, when the destination node determines a route corresponding to only one route value, the destination node generates a response message (RREP) and transmits it to the source node. The destination node may not generate a response message if the route value of the determined route is lower than the already established route value. Whenever the source node receives a response message, the source node changes the path for transmitting data (packets) from the source node to the destination node, and the destination node continuously calculates a path with higher performance through the history information. Receiving the response message from the source node can be interpreted as updating the path rather than changing the path.

The repetition control unit 150 is physically or logically connected to the node management unit 110 and the branch operation unit 130 to perform repetitive operations, and returns a result value to the node management unit 110 and the branch operation unit 130. And, depending on the embodiment, it may be implemented in a form included in the node management unit 110 or the branch operation unit 130.

3 schematically shows the format of the request message of the present invention.

Referring to FIG. 3, the request message shown in FIG. 3 includes LCR 210, BOR 220, and RSSI 230 as a first parameter, a second parameter, and a third parameter, respectively, in a header. , It can be seen that the other parts are the same as the RREQ messages transmitted and received on the existing AODV network. According to an embodiment, not only multiple parameters, but also mobility criteria corresponding to each of the multiple parameters may be stored in the header, and that the mobility criterion may be increased according to the network condition identified by the destination node, as previously described through Equation 1 There is a bar.

4 is a flowchart of an example of a method for controlling transmission and reception of an AODV network message according to the present invention.

Since the method according to FIG. 4 can be implemented by the system according to FIG. 2, it will be described below with reference to FIG. 2, and descriptions overlapping with those described in FIG. 2 will be omitted.

First, the sender node (source node) under the control of the node management unit 110 searches for a route to the destination node in its own routing table (S310).

If there is an active path, the sender node directly delivers a request message to the destination node through unicast, and if there is no active path, generates a request message (RREQ message) (S330).

When an intermediate node (relay node) receives a request message, the intermediate node checks whether it is in the entry (S350), and the destination node can generate a response message through whether the intermediate node is in the entry. Yes (S370).

When the destination node receives the request message, the route score (path value) is calculated using the hierarchical analysis method (AHP) and the multiple weighting method (SAW), and after determining one route, it is included in the response message and sent to the sender node (source node). To be delivered (S390).

The operation of the nodes constituting the entire network is controlled by the node management unit 110, and in the process of searching for a path, the branch operation unit 130 performs operations on various branches, and the repetitive variable operation is performed by the iteration control unit ( 150) will perform. Since the node management unit 110 performs various functions, it may be composed of a plurality of modules for individually performing the above-described functions.

The present invention is an invention devised to solve the reliability problem that occurs when the existing AODV network transmits/receives a message based on only the shortest hop, and the header of the request message transmitted from the source node to the destination node Multiple parameters (three parameters) that can reflect the mobility of the network are defined, and the route value is calculated through the multi-parameter and network mobility criteria in the destination node to establish an optimal route, and thus the present invention is used. Then, it is possible to expect an AODV network environment having a high packet transmission rate and a low time delay rate (prevention of delay due to packet retransmission).

The embodiment according to the present invention described above may be implemented in the form of a computer program that can be executed through various components on a computer, and such a computer program may be recorded in a computer-readable medium. In this case, the medium is a magnetic medium such as a hard disk, a floppy disk, and a magnetic tape, an optical recording medium such as a CD-ROM and a DVD, a magneto-optical medium such as a floptical disk, and a ROM. A hardware device specially configured to store and execute program instructions, such as, RAM, flash memory, and the like.

Meanwhile, the computer program may be specially designed and configured for the present invention, or may be known and usable to those skilled in the computer software field. Examples of the computer program may include not only machine language codes produced by a compiler but also high-level language codes that can be executed by a computer using an interpreter or the like.

The specific implementations described in the present invention are examples, and do not limit the scope of the present invention in any way. For brevity of the specification, descriptions of conventional electronic configurations, control systems, software, and other functional aspects of the systems may be omitted. In addition, the connection or connection members of the lines between the components shown in the drawings exemplarily represent functional connections and/or physical or circuit connections. It may be referred to as a connection, or circuit connections. In addition, if there is no specific mention such as "essential", "important", etc., it may not be an essential component for the application of the present invention.

In the specification of the present invention (especially in the claims), the use of the term "above" and a reference term similar thereto may correspond to both the singular and the plural. In addition, when a range is described in the present invention, the invention to which an individual value falling within the range is applied (unless otherwise stated), and each individual value constituting the range is described in the detailed description of the invention. Same as Finally, if there is no explicit order or contrary to the steps constituting the method according to the present invention, the steps may be performed in a suitable order. The present invention is not necessarily limited according to the order of description of the steps. The use of all examples or illustrative terms (for example, etc.) in the present invention is merely for describing the present invention in detail, and the scope of the present invention is limited by the above examples or illustrative terms unless limited by the claims. It does not become. In addition, those skilled in the art can recognize that various modifications, combinations, and changes may be configured according to design conditions and factors within the scope of the appended claims or their equivalents.

Claims (11)

As a message transmission control method of an AODV (Ad hoc On-demand Distance Vector) network operating in a network environment consisting of a source node, a relay node, and a destination node,
A request message transmitting step of controlling the source node to transmit a request message to a relay node adjacent to the source node when there is no active path from the source node to the destination node;
A message for controlling at least one relay node that has received the request message to add the information of the received relay node to the header of the request message, and to transmit the request message to which the information is added to an adjacent relay node or destination node. Relay stage; And
Controls that the destination node receives the request message to which the information is added, generates a response message based on the average value of the first parameter, the second parameter, and the third parameter included in the header of the request message, and transmits it to the source node. Including; a response message transmission step to
The first parameter,
A new link created between nodes constituting the network during a reference time; And
LCR (Link Change Rate), which is a value obtained by dividing the sum of links released between nodes constituting the network during the reference time by the reference time,
The second parameter,
It is a BOR (Buffer Occupancy Ratio), which is a value obtained by dividing the total amount of data in the buffer of the node constituting the network during the reference time by the reference time,
The third parameter,
A method for controlling AODV network message transmission and reception, characterized in that it is a received signal strength indicator (RSSI), which is a value obtained by dividing the sum of the strengths of signals received at each node constituting the network during a reference time by the reference time. delete delete delete The method of claim 1,
The step of transmitting the response message,
The average value is stored as a path value at a first time point, and if the path value at a second time point is greater than the route value at the first time point, a response message at the second time point is generated and transmitted to the source node. and,
The method according to claim 1,
A path change control step of controlling the source node receiving the response message of the second time point to change the path of the first time point stored in the path table to the route of the second time point. , AODV network message transmission and reception control method. A computer-readable recording medium storing a program for executing the method according to any one of claims 1 and 5. As a message transmission and reception control system of an AODV (Ad hoc On-demand Distance Vector) network operating in a network environment consisting of a source node, a relay node, and a destination node,
It includes a node management unit, a branch operation unit, and an iteration control unit,
The node management unit,
When the source node does not have an active path from the source node to the destination node, control to transmit a request message to a relay node adjacent to the source node,
At least one relay node that has received the request message adds the information of the received relay node to the header of the request message, and controls to transmit the request message to which the information is added to an adjacent relay node or a destination node,
Controls that the destination node receives the request message to which the information is added, generates a response message based on the average value of the first parameter, the second parameter, and the third parameter included in the header of the request message, and transmits it to the source node. and,
The branch operation unit,
Performs an operation to transmit a request message or a response message to a relay node or a destination node adjacent to the node controlled by the node management unit,
The repetition control unit,
Controls the repetitive operation of the branch operation unit in proportion to the number of relay nodes,
The first parameter,
A new link created between nodes constituting the network during a reference time; And
LCR (Link Change Rate), which is a value obtained by dividing the sum of links released between nodes constituting the network during the reference time by the reference time,
The second parameter,
It is a BOR (Buffer Occupancy Ratio), which is a value obtained by dividing the total amount of data in the buffer of the node constituting the network during the reference time by the reference time,
The third parameter,
An AODV network message transmission/reception control system, characterized in that it is a received signal strength indicator (RSSI), which is a value obtained by dividing the sum of the strengths of signals received at each node constituting the network during a reference time by the reference time. delete delete delete The method of claim 7,
The node management unit,
The average value is stored as a path value at a first time point, and if the path value at a second time point is greater than the route value at the first time point, a response message at the second time point is generated and transmitted to the source node. and,
AODV network message, characterized in that the source node receiving the response message of the second point of view changes the path of the first point of time stored in a path table to the path of the second point of view Sending and receiving control system.

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