KR102286509B1 - Delivery method for message based delay tolerant network routing protocol using characteristics of forwarding nodes, recording medium and device for performing the method - Google Patents

Abstract

The message transmission method based on the delay-tolerant network routing protocol using the characteristics of the forwarding node exchanges summary vectors (SVs) containing message information stored with each other when the transmitting node contacts the receiving node, and the message to be delivered Check that there is; classifying a contact relationship between the transmitting node and the receiving node by identifying the type of the receiving node as one of a pedestrian, a vehicle, and a tram based on the information of the summary vector; determining whether a message delivery condition to the receiving node is satisfied by using different forwarding prediction rates according to a contact relationship between the transmitting node and the receiving node; and transmitting a message to the receiving node when the message forwarding condition is satisfied. Accordingly, more efficient message delivery is possible by considering the characteristics of nodes in the PRoPHET routing protocol.

Description

DELIVERY METHOD FOR MESSAGE BASED DELAY TOLERANT NETWORK ROUTING PROTOCOL USING CHARACTERISTICS OF FORWARDING NODES, RECORDING MEDIUM AND DEVICE FOR PERFORMING THE METHOD }

The present invention relates to a method for transmitting a message based on a delay-tolerant network routing protocol using the characteristics of a forwarding node, a recording medium and an apparatus for performing the same, and more particularly, to a message transmitting node and a receiving node in which the routing path between the end-to-end is not guaranteed. Based on Probabilistic Routing Protocol using the History of Encounters and Transitivity (PRoPHET), it relates to a routing protocol that attempts to successfully deliver a message to a destination by additionally utilizing characteristics such as mobility and range of contact nodes.

Delay Tolerant Network (DTN) communicates in an environment where there is no stable communication path between the sending node and the receiving node, unlike the existing communication networks that can communicate only when there is a stable communication path between the sending node and the receiving node. This is a possible communication network.

To this end, in a delay-tolerant network, a bundle layer is defined above the transport layer so that a message can be stored for a long time until it meets a nearby communication node. In a delay-tolerant network, a node with a message to be delivered forwards the message to a neighboring node one hop away through opportunistic contact with the neighboring node.

A node with a message stores and moves the message in its own buffer with the help of the bundle layer. When it comes into contact with another node, it delivers the message if it meets the predefined delivery conditions, and repeats this message delivery process to the final destination. to convey the message. The message delivery method in such a delay-tolerant network is usually referred to as a store-carry-forward method.

In a delay-tolerant network, the method of determining whether to transmit a message to a contact node when contacting another node has the greatest influence on the performance of the routing protocol, and various methods have been studied.

Epidemic protocol, which is the simplest delay-tolerant routing protocol, unconditionally delivers its own message when it comes into contact with neighboring nodes. In an environment where the buffer size is not large enough, there is a disadvantage in that performance degradation occurs due to buffer overflow.

In the Probabilistic Routing Protocol using History of Encounters and Transitivity (PRoPHET) protocol, which is a routing protocol established as a standard by the Internet Engineering Task Force (IETF), which establishes Internet standards, the delivery predictability is calculated using past contact information between nodes. It calculates and delivers the message if the contact node has a larger delivery prediction rate than itself for the destination node of the stored message.

The propagation prediction rate between two nodes is defined as a value with a characteristic that its value increases at every contact and its value decreases exponentially as time increases after the most recent contact.

However, since the PRoPHET protocol does not consider other characteristics of a node other than the forward prediction rate calculated using contact information with other nodes in the past, there is a limit to improving performance in a limited buffer capacity. Unnecessary message transmission occurs.

Transmission of such unnecessary messages increases the overhead of the entire network and ultimately causes a problem of lowering the transmission success rate of the entire network.

KR 10-1471276 B1 KR 10-2019-0035056 A KR 10-2018-0092943 A

A. Lindgren, A. Doria, E. Davies, and S. Grasic, "Probabilistic routing protocol for intermittently connected networks", IETF RFC 6693, Aug. 2012 D. Y. Seo, Y. W. Chung, “An Efficient Context-aware Opportunistic Routing Protocol”, The Transactions of the Korean Institute of Electrical Engineers, 65(12), 2218-2224, Dec. 2016

Accordingly, it is an object of the present invention to provide a message transmission method based on a delay-tolerant network routing protocol using the characteristics of a forwarding node.

Another object of the present invention is to provide a recording medium in which a computer program for performing a message transmission method based on a delay tolerant network routing protocol using the characteristics of the forwarding node is recorded.

Another object of the present invention is to provide an apparatus for performing a message transmission method based on a delay tolerance network routing protocol using the characteristics of the forwarding node.

A method for transmitting a message based on a delay-tolerant network routing protocol using the characteristics of a forwarding node according to an embodiment for realizing the object of the present invention includes: Checking whether there is a message scheduled to be delivered by exchanging a summary vector (SV); classifying a contact relationship between the transmitting node and the receiving node by identifying the type of the receiving node as one of a pedestrian, a vehicle, and a tram based on the information of the summary vector; determining whether a message delivery condition to the receiving node is satisfied by using different forwarding prediction rates according to a contact relationship between the transmitting node and the receiving node; and transmitting a message to the receiving node when the message forwarding condition is satisfied.

In an embodiment of the present invention, the step of determining whether the message delivery condition to the receiving node is satisfied may include comparing the delivery prediction rate of the receiving node with a delivery prediction rate set differently according to the contact relationship, and is greater than the set delivery prediction rate. In this case, it can be determined that the message delivery condition is satisfied.

In an embodiment of the present invention, the contact relationship between the transmitting node and the receiving node is a tram and a tram, a tram and a vehicle, a tram and a pedestrian, a vehicle and a tram, a vehicle and a vehicle, a vehicle and a pedestrian, a pedestrian and a tram, and a pedestrian It can be classified into nine relationships between vehicles and pedestrians.

In an embodiment of the present invention, the set propagation prediction rates of the contact relationship between the transmitting node and the receiving node are P1, P2, P3, P4, P5, P6, P7, P8 and P9, which are probability values of 0 or more and 1 or less, respectively. can be set.

In an embodiment of the present invention, the values of P1, P2, P3, P4, P5, P6, P7, and P8 are preset, and when the receiving node is a tram, the P1, P4, and P7 values are the values of the receiving node being a vehicle. It may be set to a value lower than the P2, P5, and P8 values of the case.

In an embodiment of the present invention, P2, P5, and P8 values when the receiving node is a vehicle may be set to lower values than P3 and P6 values when the receiving node is a pedestrian.

In an embodiment of the present invention, when the receiving node is a tram, the values of P1, P4, and P7 are set to 0, when the receiving node is a pedestrian, the values of P3 and P6 are set to 1, and the P9 value is the transmission It can be set as the node's forwarding prediction rate.

In an embodiment of the present invention, it may be repeatedly performed for all messages stored in the transmitting node.

In a computer-readable storage medium according to an embodiment for realizing another object of the present invention, a computer program for performing a message transmission method based on a delay tolerance network routing protocol using the characteristics of the forwarding node is recorded, there is.

A message transmission apparatus based on a delay tolerance network routing protocol using the characteristics of a forwarding node according to an embodiment for realizing another object of the present invention, when a transmitting node contacts a receiving node, transmits message information stored with each other an information check unit that exchanges a summary vector (SV) contained therein and checks whether there is a message scheduled to be delivered; a contact relationship classification unit for classifying a contact relationship between the transmission node and the reception node by identifying the type of the reception node as one of a pedestrian, a vehicle, and a tram based on the information of the summary vector; a message forwarding condition determining unit configured to determine whether a message forwarding condition to the receiving node is satisfied by using a delivery prediction rate set differently according to a contact relationship between the transmitting node and the receiving node; and a message transmitting unit that transmits a message to the receiving node when the message forwarding condition is satisfied.

In an embodiment of the present invention, the message delivery condition determining unit compares the delivery prediction rate of the receiving node with a delivery prediction rate set differently according to the contact relationship, and satisfies the message delivery condition if it is greater than or equal to the set delivery prediction rate It can be judged that

In an embodiment of the present invention, the contact relationship between the transmitting node and the receiving node is a tram and a tram, a tram and a vehicle, a tram and a pedestrian, a vehicle and a tram, a vehicle and a vehicle, a vehicle and a pedestrian, a pedestrian and a tram, and a pedestrian It is classified into nine relationships between vehicles and pedestrians and pedestrians, and the set transmission prediction rates of the contact relationship between the transmitting node and the receiving node are P1, P2, P3, P4, P5, P6, which are probability values of 0 or more and 1 or less, respectively. It can be set to P7, P8 and P9.

In an embodiment of the present invention, the values of P1, P2, P3, P4, P5, P6, P7, and P8 are preset, and when the receiving node is a tram, the P1, P4, and P7 values are the values of the receiving node being a vehicle. is set to a lower value than the P2, P5, and P8 values in the case of the receiving node, and the P2, P5, and P8 values when the receiving node is a vehicle may be set to a value lower than the P3 and P6 values when the receiving node is a pedestrian. .

In an embodiment of the present invention, when the receiving node is a tram, the values of P1, P4, and P7 are set to 0, when the receiving node is a pedestrian, the values of P3 and P6 are set to 1, and the P9 value is the transmission It can be set as the node's forwarding prediction rate.

According to the message transmission method based on the delay-tolerant network routing protocol using the characteristics of the forwarding node, the contact relationship between nodes is distinguished in consideration of the mobility of each node in the delay-tolerant network environment composed of pedestrian, vehicle, and tram nodes, and the message By setting the delivery conditions differently for each contact relationship, sophisticated and improved transmission efficiency can be realized by utilizing the message delivery conditions along with the delivery prediction rate of the existing PRoPHET.

1 is a diagram for explaining a delay-tolerant network environment composed of pedestrians, vehicles, and tram nodes according to the present invention.
2 is a block diagram of an apparatus for transmitting a message based on a delay-tolerant network routing protocol using the characteristics of a forwarding node according to an embodiment of the present invention.
3 is a table of message delivery conditions according to a contact relationship between a transmitting node and a receiving node in the present invention.
4 is a table comparing characteristics of a protocol of the prior art and a protocol of the present invention.
5 is a flowchart of a message transmission method based on a delay-tolerant network routing protocol using the characteristics of a forwarding node according to an embodiment of the present invention.
6 is a table of an environment assumed in simulation for performance comparison between the present invention and the prior art.
7 is a chart comparing the present invention and the prior art in terms of transmission rate while changing the buffer size of the pedestrian.
8 is a chart comparing the present invention and the prior art in terms of load factor while changing the buffer size of pedestrians.
9 is a chart comparing the present invention and the prior art in terms of transmission delay while changing the buffer size of the pedestrian.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0023] Reference is made to the accompanying drawings, which show by way of illustration specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention are different but need not be mutually exclusive. For example, certain shapes, structures, and characteristics described herein with respect to one embodiment may be embodied in other embodiments without departing from the spirit and scope of the invention. In addition, it should be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the present invention. Accordingly, the detailed description set forth below is not intended to be taken in a limiting sense, and the scope of the invention, if properly described, is limited only by the appended claims, along with all scope equivalents to those claimed. Like reference numerals in the drawings refer to the same or similar functions throughout the various aspects.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the drawings.

1 is a diagram for explaining a delay-tolerant network environment composed of pedestrians, vehicles, and tram nodes according to the present invention. 2 is a block diagram of an apparatus for transmitting a message based on a delay-tolerant network routing protocol using the characteristics of a forwarding node according to an embodiment of the present invention.

According to the present invention, in a network environment 1 composed of moving nodes, that is, pedestrian, car, and tram nodes as shown in FIG. 1, the routing path between the message sending node and the receiving node is not guaranteed. In a Delay Tolerant Network (DTN) that uses a store-carry-forwarding method of message forwarding through a relay node, the forwarding prediction rate is calculated using past contact information between nodes, It is based on Probabilistic Routing Protocol (PRoPHET) using the History of Encounters and Transitivity (PRoPHET) technique, which uses this as a message delivery condition when contacting nodes.

In the present invention, the characteristics of the tram node in which the node of the delay-tolerant network periodically moves along a predetermined path in an environment classified as a pedestrian, a car, and a tram, and a wider movement range than that of a pedestrian at a faster speed We propose an effective routing protocol using the characteristics of a forwarding node to improve performance by considering the characteristics of a vehicle node that can move to

In the present invention, the relationship between the contact nodes of the 'sending node-receiving node' is defined as 'tram-tram', 'tram-vehicle', 'tram-pedestrian', 'vehicle-tram', 'vehicle-vehicle', 'vehicle-pedestrian' ', 'Pedestrian-Tram', 'Pedestrian-Vehicle', and 'Pedestrian-Pedestrian' are divided into 9 categories to define effective message delivery standards in each relationship, thereby improving performance.

Referring to FIG. 2 , a message transmission apparatus 10 (hereinafter referred to as a device) based on a delay tolerant network routing protocol using the characteristics of a forwarding node according to the present invention includes an information confirmation unit 110 , a contact relationship classification unit 130 , and message forwarding. It includes a condition determination unit 150 and a message transmission unit 170 .

In the device 10 of the present invention, software (application) for automatically verifying the validity of an API call may be installed and executed, and the information check unit 110 , the contact relationship classifier 130 , and the message transfer The configuration of the condition determination unit 150 and the message transmission unit 170 is to be controlled by software for performing message transmission based on a delay tolerance network routing protocol using the characteristics of the forwarding node executed in the device 10. can

The device 10 may be a separate node or a module of a node. In addition, the configuration of the information check unit 110 , the contact relationship classifier 130 , the message delivery condition determination unit 150 , and the message transmission unit 170 is formed as an integrated module or is composed of one or more modules. can get However, on the contrary, each configuration may be formed of a separate module.

The device 10 may be mobile. The apparatus 10 is a device, an apparatus, a terminal, a user equipment (UE), a mobile station (MS), a wireless device, and other terms such as a handheld device. can be called

The device 10 may execute or manufacture various software based on an operating system (OS), that is, the system. The operating system is a system program for software to use the hardware of the device, and is a mobile computer operating system such as Android OS, iOS, Windows Mobile OS, Bada OS, Symbian OS, Blackberry OS, and Windows series, Linux series, Unix series, It can include all computer operating systems such as MAC, AIX, and HP-UX.

When the transmitting node contacts the receiving node, the information check unit 110 checks whether there is a message scheduled to be delivered by exchanging summary vectors (SVs) containing message information stored with each other.

The contact relationship classification unit 130 classifies the contact relationship between the transmission node and the reception node by identifying the type of the reception node as one of a pedestrian, a vehicle, and a tram based on the information of the summary vector.

When the transmitting node is a tram, the relationship between the two nodes is classified into 'tram-tram', 'tram-vehicle', and 'tram-pedestrian' according to the node type of the receiving node.

When the transmitting node is a vehicle, the relationship between the two nodes is classified into 'vehicle-tram', 'vehicle-vehicle', and 'vehicle-pedestrian' according to the node type of the receiving node.

When the transmitting node is a pedestrian, the relationship between the two nodes is classified into 'pedestrian-tram', 'pedestrian-vehicle', and 'pedestrian-pedestrian' according to the node type of the receiving node, the transmitting node and the receiving node There are a total of 9 contact relationships, and the delivery prediction rate, which is the standard for message delivery, is used differently according to each relationship.

The message forwarding condition determining unit 150 determines whether the message forwarding condition to the receiving node is satisfied by using different forwarding prediction rates according to the contact relationship between the transmitting node and the receiving node.

The message delivery condition determining unit 150 compares the delivery prediction rate of the receiving node with a delivery prediction rate set differently according to the contact relationship, and determines that the message delivery condition is satisfied if it is greater than or equal to the set delivery prediction rate do.

A delivery prediction rate according to a contact relationship between the transmitting node and the receiving node is as follows. P1 to P8 are defined as probability values of 0 or more and 1 or less, respectively. Among them, values of P1, P2, P3, P4, P5, P6, P7, and P8 are preset, and P9 may be set differently as the PRoPHET delivery prediction rate.

'Tram-tram': P1

'tram-vehicle': P2

'Tram-Pedestrian': P3

'Vehicle-tram': P4

'vehicle-vehicle': P5

'Vehicle-Pedestrian': P6

'Pedestrian-tram': P7

'Pedestrian-Vehicle': P8

'Pedestrian-Pedestrian': P9

The message delivery conditions for each node type of the present invention are summarized in a table in FIG. 3 . 3 is a table of message delivery conditions according to a contact relationship between a transmitting node and a receiving node in the present invention.

Specifically, when the relationship between the contact nodes of the 'sending node-receiving node' is 'tram-tram', the message is delivered to the receiving node only when the forwarding prediction rate of the receiving node is greater than or equal to P1.

When the relationship between the contact nodes of the 'sending node-receiving node' is 'tram-vehicle', the message is delivered to the receiving node only when the forwarding prediction rate of the receiving node is greater than or equal to P2.

When the relationship between the contact nodes of the 'sender node-receiver node' is 'tram-pedestrian', the message is delivered to the receiving node only when the forwarding prediction rate of the receiving node is greater than or equal to P3.

When the relationship between the contact nodes of the 'sending node-receiving node' is 'vehicle-tram', the message is delivered to the receiving node only when the forwarding prediction rate of the receiving node is greater than or equal to P4.

When the relationship between the contact nodes of the 'sending node-receiving node' is 'vehicle-vehicle', the message is delivered to the receiving node only when the forwarding prediction rate of the receiving node is greater than or equal to P5.

When the relationship between the contact nodes of the 'sending node-receiver node' is 'vehicle-pedestrian', the message is delivered to the receiving node only when the forwarding prediction rate of the receiving node is greater than or equal to P6.

If the relationship between the contact nodes of the 'sender node-receiver node' is 'pedestrian-tram', the message is delivered to the receiving node only when the receiving node's delivery prediction rate is greater than or equal to P7.

If the relationship between the contact nodes of the 'sender node-receiver node' is 'pedestrian-vehicle', the message is delivered to the receiving node only when the forwarding prediction rate of the receiving node is greater than or equal to P8.

When the relationship between the contact nodes of the 'sender node-receiver node' is 'pedestrian-pedestrian', the message is delivered to the receiving node only when the forwarding prediction rate of the receiving node is greater than or equal to the forwarding prediction rate of the transmitting node.

As an embodiment, the delivery prediction rates P1, P4, and P7 values to be used as message delivery conditions when the receiving node is a tram are set to very low values, so that the delivery conditions when transmitting messages to a tram node having a large message storage space and excellent mobility are very high. This allows you to store many messages by mitigating it.

In addition, the delivery prediction rates P2, P5, and P8, which will be used as message delivery conditions when the receiving node is a vehicle, are also set to low values to relax the message delivery conditions to vehicle nodes with superior mobility compared to pedestrian nodes to send more messages. to be able to save

In the case of P3 and P6, where the receiving node is a pedestrian, the message is transmitted only when the pedestrian node is the destination, and in the case of contact between pedestrian nodes, the value of P9 enables message transmission using the comparison condition of the transmission prediction rate of the existing PRoPHET.

For example, when the receiving node is a tram, the P1, P4, and P7 values are set to 0, when the receiving node is a pedestrian, the P3 and P6 values are set to 1, and the P9 value is the transmission of the transmitting node It can be set to a prediction rate.

Through this, it is possible to improve the performance of a protocol that always transmits a message when the receiving node is a tram, and transmits a message only when the receiving node is a destination node when the transmitting node is a tram and the receiving node is a vehicle/pedestrian.

The message transmitting unit 170 transmits a message to the receiving node when the message forwarding condition is satisfied. This procedure operates so that it can be performed on all messages during a given contact time.

Prior art [Non-Patent Document 2: D. Y. Seo, Y. W. Chung, “An Efficient Context-aware Opportunistic Routing Protocol”, The Transactions of the Korean Institute of Electrical Engineers, 65(12), 2218-2224, Dec. 2016] utilizes the characteristics of a tram node that periodically moves a predetermined route in a delay-tolerant network environment classified as a pedestrian, a car, and a tram. The characteristics of the vehicle moving at a wider range and at high speed were not considered.

In the present invention, the PRoPHET protocol is assumed as the basic protocol, and among the existing studies related to the PRoPHET protocol, the existing research utilizing the characteristics of a tram that periodically moves along a designated route with an excellent buffer size in a delay-tolerant network composed of pedestrians, vehicles, and trams. expanded.

To this end, we proposed an effective routing protocol that additionally considers the characteristics of a vehicle moving over a wide range at higher speed with a larger buffer size than that of a pedestrian.

In the protocol proposed in the present invention, effective message delivery in each relationship using the relationship of a total of 9 contact nodes compared to the conventional technique consisting of an operation based on the relationship between the contact nodes divided into 4 when two nodes are in contact The standard was defined and performance was improved through this.

In the protocol proposed in the present invention, compared to a battery-operated pedestrian terminal, it can have sufficient power and a sufficient buffer space, and the performance is improved in consideration of the characteristics of a vehicle moving at a higher speed and in a wide range. To this end, a total of nine combinations of a case in which a transmitting node and a receiving node are a tram, a vehicle, and a pedestrian, respectively, are considered by separating the pedestrian and the vehicle as shown in FIG. 3 .

Then, when the receiving node is a vehicle, the values of P2, P5, and P8 are defined as appropriate values between 0 and 1, and when the delivery prediction rate of the vehicle that is the receiving vehicle to the destination node of the message under consideration is greater than this value, the message to convey

However, for fair comparison with the conventional protocol, when the simulation is performed, the values of P1, P4, and P7 are assumed to be 0 when the tram is the receiving node. The corresponding values of P3 and P6 were assumed to be 1.

Through this, we tried to improve the performance of the protocol that always transmits a message when the receiving node is a tram, and transmits a message only when the receiving node is a destination node when the transmitting node is a tram and the receiving node is a vehicle/pedestrian.

4 is a table comparing characteristics of a protocol of the prior art and a protocol of the present invention.

4 , the characteristics of the existing protocol and the protocol proposed in the present invention are classified as the characteristics of the transmitting node and the receiving node, the buffer size of the node, the combination of message delivery conditions of the transmitting node and the receiving node to be considered, when the receiving node is a vehicle Compare in terms of message delivery conditions.

The protocol proposed in the present invention considers a vehicle having a larger buffer than a pedestrian by further subdividing the characteristics of the vehicle/pedestrian that were considered the same in the previous study. Thereafter, in order to effectively reflect these characteristics, different message delivery conditions are assumed when the receiving node is a vehicle and a pedestrian, and effective message delivery is attempted.

5 is a flowchart of a message transmission method based on a delay-tolerant network routing protocol using the characteristics of a forwarding node according to an embodiment of the present invention.

The message transmission method based on the delay tolerance network routing protocol using the characteristics of the forwarding node according to the present embodiment may proceed in substantially the same configuration as the apparatus 10 of FIG. 2 . Accordingly, the same components as those of the device 10 of FIG. 2 are given the same reference numerals, and repeated descriptions are omitted.

In addition, the message transmission method based on the delay-tolerant network routing protocol using the characteristics of the forwarding node according to the present embodiment is to be executed by software (application) for performing message transmission based on the delay-tolerant network routing protocol using the characteristics of the forwarding node. can

Referring to FIG. 5 , in the message transmission method based on the delay tolerance network routing protocol using the characteristics of the forwarding node according to the present embodiment, when the transmitting node comes into contact with the receiving node (step S10), it contains message information stored with each other. By exchanging a summary vector (SV), it is checked whether there is a message scheduled to be delivered (step S20).

Based on the information of the summary vector, the types of nodes (pedestrians, vehicles, trams) between the contact nodes are checked, and a preparation process for comparing message delivery conditions according to node types is performed. Specifically, the type of the receiving node is checked as one of pedestrian, vehicle, and tram (step S30), and a contact relationship between the transmitting node and the receiving node is classified using the checked type of the receiving node (step S40). .

When the transmitting node is a tram, the relationship between the two nodes is classified into 'tram-tram', 'tram-vehicle', and 'tram-pedestrian' according to the node type of the receiving node.

When the transmitting node is a vehicle, the relationship between the two nodes is classified into 'vehicle-tram', 'vehicle-vehicle', and 'vehicle-pedestrian' according to the node type of the receiving node.

When the transmitting node is a pedestrian, the relationship between the two nodes is classified into 'pedestrian-tram', 'pedestrian-vehicle', and 'pedestrian-pedestrian' according to the node type of the receiving node, the transmitting node and the receiving node There are a total of 9 contact relationships, and the delivery prediction rate, which is the standard for message delivery, is used differently according to each relationship.

It is determined whether a message delivery condition to the receiving node is satisfied by using a delivery prediction rate set differently according to a contact relationship between the transmitting node and the receiving node (step S50).

In step S50, the delivery prediction rate of the receiving node is compared with a delivery prediction rate set differently according to the contact relationship, and if it is greater than or equal to the set delivery prediction rate, it is determined that the message delivery condition is satisfied.

A delivery prediction rate according to a contact relationship between the transmitting node and the receiving node is as follows. P1 to P8 are defined as probability values of 0 or more and 1 or less, respectively. Among them, values of P1, P2, P3, P4, P5, P6, P7, and P8 are preset, and P9 may be set differently as the PRoPHET delivery prediction rate.

'Tram-tram': P1

'tram-vehicle': P2

'Tram-Pedestrian': P3

'Vehicle-tram': P4

'vehicle-vehicle': P5

'Vehicle-Pedestrian': P6

'Pedestrian-tram': P7

'Pedestrian-Vehicle': P8

'Pedestrian-Pedestrian': P9

The message delivery conditions for each node type of the present invention are summarized in a table in FIG. 3 . 3 is a table of message delivery conditions according to a contact relationship between a transmitting node and a receiving node in the present invention.

Specifically, when the relationship between the contact nodes of the 'sending node-receiving node' is 'tram-tram', the message is delivered to the receiving node only when the forwarding prediction rate of the receiving node is greater than or equal to P1.

When the relationship between the contact nodes of the 'sending node-receiving node' is 'tram-vehicle', the message is delivered to the receiving node only when the forwarding prediction rate of the receiving node is greater than or equal to P2.

When the relationship between the contact nodes of the 'sender node-receiver node' is 'tram-pedestrian', the message is delivered to the receiving node only when the forwarding prediction rate of the receiving node is greater than or equal to P3.

When the relationship between the contact nodes of the 'sending node-receiving node' is 'vehicle-tram', the message is delivered to the receiving node only when the forwarding prediction rate of the receiving node is greater than or equal to P4.

When the relationship between the contact nodes of the 'sending node-receiving node' is 'vehicle-vehicle', the message is delivered to the receiving node only when the forwarding prediction rate of the receiving node is greater than or equal to P5.

When the relationship between the contact nodes of the 'sending node-receiver node' is 'vehicle-pedestrian', the message is delivered to the receiving node only when the forwarding prediction rate of the receiving node is greater than or equal to P6.

If the relationship between the contact nodes of the 'sender node-receiver node' is 'pedestrian-tram', the message is delivered to the receiving node only when the receiving node's delivery prediction rate is greater than or equal to P7.

If the relationship between the contact nodes of the 'sender node-receiver node' is 'pedestrian-vehicle', the message is delivered to the receiving node only when the forwarding prediction rate of the receiving node is greater than or equal to P8.

When the relationship between the contact nodes of the 'sender node-receiver node' is 'pedestrian-pedestrian', the message is delivered to the receiving node only when the forwarding prediction rate of the receiving node is greater than or equal to the forwarding prediction rate of the transmitting node.

As an embodiment, the delivery prediction rates P1, P4, and P7 values to be used as message delivery conditions when the receiving node is a tram are set to very low values, so that the delivery conditions when transmitting messages to a tram node having a large message storage space and excellent mobility are very high. This allows you to store many messages by mitigating it.

In addition, the delivery prediction rates P2, P5, and P8, which will be used as message delivery conditions when the receiving node is a vehicle, are also set to low values to relax the message delivery conditions to vehicle nodes with superior mobility compared to pedestrian nodes to send more messages. to be able to save

In the case of P3 and P6, where the receiving node is a pedestrian, the message is transmitted only when the pedestrian node is the destination, and in the case of contact between pedestrian nodes, the value of P9 enables message transmission using the comparison condition of the transmission prediction rate of the existing PRoPHET.

For example, when the receiving node is a tram, the P1, P4, and P7 values are set to 0, when the receiving node is a pedestrian, the P3 and P6 values are set to 1, and the P9 value is the transmission of the transmitting node It can be set to a prediction rate.

Through this, it is possible to improve the performance of a protocol that always transmits a message when the receiving node is a tram, and transmits a message only when the receiving node is a destination node when the transmitting node is a tram and the receiving node is a vehicle/pedestrian.

When the message forwarding condition is satisfied, the message is transmitted to the receiving node (step S60).

This procedure makes it possible to perform all messages during a given contact time (steps S70 and S80).

In order to analyze the performance of the protocol proposed by the present invention in detail, the Opportunistic Network Environment (ONE) simulator [The Opportunistic Network Environment Simulator, http://www.netlab. tkk.fi/tutkimus/dtn/theone/(accessed: Sep. 16, 2019)] and [A. Keranen, J. Ott, and T. Karkkainen, "The ONE Simulator for DTN Protocol Evaluation", Proceedings of International Conference on Simulation Tools and Techniques, Rome, Italy, Article No. 55:1-10, Mar. 2009] was used to analyze the transmission rate, load factor, and transmission delay defined in Equations 1 to 3 below.

[Equation 1]

[Equation 2]

[Equation 3]

In this simulation, the proposed protocol and the conventional protocol [Non-patent Document 2: DY Seo, YW Chung, "An Efficient Context-aware Opportunistic Routing Protocol", The Transactions of the Korean Institute of Electrical Engineers, 65 ( 12), 2218-2224, Dec. 2016], the same simulation environment as that used in the existing protocol as shown in FIG. 6 was assumed.

However, for the performance analysis simulation of the proposed protocol that reflects the characteristics of the vehicle that can receive power and operate a superior buffer space compared to the pedestrian terminal, the buffer size of the pedestrian terminal in the previous study was set to 10Mbytes ~ 100Mbytes. The buffer size was set to 500Mbytes in both the proposed protocol and the existing protocol.

7 is a graph comparing transmission rates while changing a pedestrian's buffer size from 10 Mbytes to 100 Mbytes in units of 10 Mbytes. It can be seen that the protocol proposed in the present invention always has superior performance compared to the existing protocol in a situation where the values of P2, P5, and P8 are variously changed to 0, 0.4, and 08, and has a maximum of about 2.4% superior performance.

This is compared to the existing protocol in which a message is received only when the vehicle is a destination node when the transmission node is a tram by assuming the same characteristics of pedestrians and vehicles, but in the proposed protocol, in the case of a vehicle, preset P2, P5 , this is because, when the delivery prediction rate is larger than that of P8, the message can be spread properly by allowing the message to be received, and through this, the message can be delivered effectively.

8 is a graph comparing the load factor while changing the pedestrian's buffer size from 10 Mbytes to 100 Mbytes in units of 10 Mbytes. In the protocol proposed in the present invention, when the values of P2, P5, and P8 are variously changed to 0, 0.4, and 08, compared to the existing protocol, when the vehicle is a receiving node, the number of transmitted messages increases, but the number of transmitted messages is relatively As can be seen by inferring from Equation 2, it always has excellent performance regardless of various values of P2, P5, and P8 compared to the proposed protocol, and it can be confirmed that it has a lower load factor of up to 17.5%.

9 is a graph comparing the transmission delay while changing the pedestrian's buffer size from 10 Mbytes to 100 Mbytes in units of 10 Mbytes. The protocol proposed in the present invention delivers more messages to vehicles with greater movement speed and movement range than pedestrians, so regardless of the various values of P2, P5, and P8, it always has superior performance compared to the existing protocol and delivers up to 4.9% less It can be seen that there is a delay.

Also, as for the delivery delay in all protocols, it can be confirmed that the message overflow decreases as the size of the pedestrian's buffer increases, so that the delivery delay also decreases.

In the present invention, an effective routing protocol using the characteristics of a forwarding node to improve performance in consideration of the characteristics of a vehicle that has a larger buffer size than that of a pedestrian and moves in a wide range at higher speed was proposed and its performance was analyzed.

As a result of the performance analysis, the protocol proposed in the present invention differentiates the message delivery criteria of the receiving node from the vehicle and pedestrian nodes and efficiently utilizes the mobility of the vehicle node. It was confirmed that 4.9% had less propagation delay.

Through the above performance analysis results, in a delay-tolerant network environment composed of various nodes, performance can be effectively improved by setting message delivery conditions suitable for the characteristics of each node, effectively considering the characteristics of various nodes, such as the movement range, movement path, and movement speed of the node. It has been verified that

Such a method of transmitting a message based on a delay-tolerant network routing protocol using the characteristics of a forwarding node may be implemented as an application or implemented in the form of a program command that may be executed through various computer components and recorded on a computer-readable recording medium. there is. The computer-readable recording medium may include program instructions, data files, data structures, etc. alone or in combination.

The program instructions recorded on the computer-readable recording medium are specially designed and configured for the present invention, and may be known and available to those skilled in the computer software field.

Examples of the computer-readable recording medium include a hard disk, a magnetic medium such as a floppy disk and a magnetic tape, an optical recording medium such as a CD-ROM, a DVD, and a magneto-optical medium such as a floppy disk. media), and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like.

Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device may be configured to operate as one or more software modules to perform processing according to the present invention, and vice versa.

Although the above has been described with reference to the embodiments, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention described in the claims below You will understand.

The present invention proposes an effective delay-tolerant network routing protocol considering different characteristics of message relay nodes. To this end, the proposed protocol, which consists of message relay nodes such as pedestrians, vehicles, and trams, has a larger buffer size than pedestrians and effectively utilizes the characteristics of vehicles moving over a wide range at high speed. As a result of performance analysis through simulation, it was confirmed that the protocol proposed in the present invention had a transmission rate improved by up to 2.4%, a load factor reduced by up to 17.5%, and a transmission delay reduced by up to 4.9% compared to the existing protocol. Accordingly, since a message can be efficiently transmitted in an environment in which a stable end-to-end communication path does not exist between a source node and a destination node, it can be usefully applied to information communication fields requiring data transmission.

10: PRoPHET-based message transmission device using characteristics of forwarding node
110: information confirmation unit
130: contact relationship classification unit
150: message delivery condition determination unit
170: message transmission unit

Claims (13)

checking whether there is a message to be delivered by exchanging summary vectors (SVs) containing message information stored with each other when the transmitting node contacts the receiving node;
classifying a contact relationship between the transmitting node and the receiving node by identifying the type of the receiving node as one of a pedestrian, a vehicle, and a tram based on the information of the summary vector;
determining whether a message delivery condition to the receiving node is satisfied by using different forwarding prediction rates according to a contact relationship between the transmitting node and the receiving node; and
Including; transmitting a message to the receiving node when the message forwarding condition is satisfied;
The step of determining whether a message delivery condition to the receiving node is satisfied by using a delivery prediction rate set differently according to a contact relationship between the transmitting node and the receiving node includes:
The message delivery condition by comparing the forwarding prediction rate of the transmitting node and the receiving node differently from each other, and comparing the forwarding prediction rate of the receiving node with the size of the forwarding prediction rate according to the contact relationship between the transmitting node and the receiving node is to determine whether it is satisfied with
The contact relationship between the transmitting node and the receiving node is 9 types: tram and tram, tram and vehicle, tram and pedestrian, vehicle and tram, vehicle and vehicle, vehicle and pedestrian, pedestrian and tram, pedestrian and vehicle, and pedestrian and pedestrian classified as,
A method for transmitting a message based on a delay-tolerant network routing protocol using a characteristic of a forwarding node, wherein, only in the case of a contact between pedestrian nodes among the contact relationships, the delivery prediction rate according to the contact relationship is set differently as the PRoPHET delivery prediction rate.
The method of claim 1, wherein determining whether a message delivery condition to the receiving node is satisfied comprises:
A delay tolerant network using the characteristics of a forwarding node, which compares the delivery prediction rate of the receiving node with a delivery prediction rate set differently according to the contact relationship, and determines that the message delivery condition is satisfied if it is greater than or equal to the set delivery prediction rate A message transmission method based on a routing protocol.
According to claim 1,
The set propagation prediction rates of the contact relationship between the transmitting node and the receiving node are set to P1, P2, P3, P4, P5, P6, P7, P8 and P9, which are probability values of 0 or more and 1 or less, respectively. A message transmission method based on a delay-tolerant network routing protocol using
4. The method of claim 3,
The values of P1, P2, P3, P4, P5, P6, P7, P8 are preset,
When the receiving node is a tram, the P1, P4, and P7 values are set to a value lower than the P2, P5, and P8 values when the receiving node is a vehicle. transmission method.
5. The method of claim 4,
When the receiving node is a vehicle, the P2, P5, and P8 values are set to a value lower than the P3 and P6 values when the receiving node is a pedestrian. Delay tolerance network routing protocol-based message transmission method using the characteristics of the forwarding node .
6. The method of claim 5,
When the receiving node is a tram, the values of P1, P4, and P7 are set to 0,
When the receiving node is a pedestrian, the values of P3 and P6 are set to 1, a message transmission method based on a delay tolerance network routing protocol using a characteristic of a forwarding node.
According to claim 1,
A method for transmitting a message based on a delay-tolerant network routing protocol using characteristics of a forwarding node, which is repeatedly performed on all messages stored in the transmitting node.
The computer-readable storage medium in which a computer program is recorded for performing the message transmission method based on the delay-tolerant network routing protocol using the characteristics of the forwarding node according to claim 1 .
When the transmitting node comes into contact with the receiving node, the information check unit for checking whether there is a message to be delivered by exchanging a summary vector (SV) containing the message information stored with each other;
a contact relationship classification unit for classifying a contact relationship between the transmission node and the reception node by identifying the type of the reception node as one of a pedestrian, a vehicle, and a tram based on the information of the summary vector;
a message forwarding condition determining unit configured to determine whether a message forwarding condition to the receiving node is satisfied by using a delivery prediction rate set differently according to a contact relationship between the transmitting node and the receiving node; and
and a message transmission unit that transmits a message to the receiving node when the message forwarding condition is satisfied;
The message delivery condition determination unit,
The message delivery condition by comparing the forwarding prediction rate of the transmitting node and the receiving node differently from each other, and comparing the forwarding prediction rate of the receiving node with the size of the forwarding prediction rate according to the contact relationship between the transmitting node and the receiving node to determine whether it is satisfied
The contact relationship between the transmitting node and the receiving node is 9 types: tram and tram, tram and vehicle, tram and pedestrian, vehicle and tram, vehicle and vehicle, vehicle and pedestrian, pedestrian and tram, pedestrian and vehicle, and pedestrian and pedestrian classified as,
A message transmission apparatus based on a delay-tolerant network routing protocol using the characteristics of a forwarding node, wherein, only in the case of a contact between pedestrian nodes among the contact relationships, the delivery prediction rate according to the contact relationship is set differently as the PRoPHET delivery prediction rate.
The method of claim 9, wherein the message delivery condition determining unit,
A delay tolerant network using the characteristics of a forwarding node, which compares the delivery prediction rate of the receiving node with a delivery prediction rate set differently according to the contact relationship, and determines that the message delivery condition is satisfied if it is greater than or equal to the set delivery prediction rate A message transmission device based on a routing protocol.
10. The method of claim 9,
The set propagation prediction rates of the contact relationship between the transmitting node and the receiving node are set to P1, P2, P3, P4, P5, P6, P7, P8 and P9, which are probability values of 0 or more and 1 or less, respectively. Message transmission device based on delay-tolerant network routing protocol using
12. The method of claim 11,
The values of P1, P2, P3, P4, P5, P6, P7, P8 are preset,
P1, P4, and P7 values when the receiving node is a tram are set to values lower than P2, P5, and P8 values when the receiving node is a vehicle,
When the receiving node is a vehicle, the P2, P5, and P8 values are set to lower values than the P3 and P6 values when the receiving node is a pedestrian. Delay tolerance network routing protocol-based message transmission device using the characteristics of the forwarding node .
13. The method of claim 12,
When the receiving node is a tram, the values of P1, P4, and P7 are set to 0,
When the receiving node is a pedestrian, the P3 and P6 values are set to 1, and the P9 value is set to the transmission prediction rate of the transmitting node.

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