KR102054731B1 - Underwater communication apparatus using seamless DTN (Delay Tolerant Network) protocol and method thereof - Google Patents

Abstract

The present invention relates to an underwater communication apparatus using a seamless DTN protocol that enables seamless underwater communication between divers in underwater using a seamless Delay Tolerant Network (DTN) protocol, and a method for underwater communication. .
The underwater communication device using the seamless DTN protocol according to the present invention is an underwater communication device mounted on a plurality of divers and constitutes a diver network (DN), which is connected to a lower data link layer to interface with an external device. Providing a data link abstract layer; And a DTN function that stores and retransmits the transmitted data in a buffer to perform DTN function for underwater communication, and forms a network topology that forms and manages a DN topology based on underwater MANET. The management unit, the environment information collection and management unit for collecting and managing the environment information by periodically analyzing the packets received through the overhearing of multiple communication media, the environment for storing the environment information collected and managed Selecting the data link layer through the machine learning based on the surrounding situation information collected and stored in the information storage unit, the surrounding situation information collection and management unit and the surrounding situation information storage unit, and establishing an operation policy And an S-DTN layer including an operation unit.

Description

Underwater communication apparatus using seamless DTN (Delay Tolerant Network) protocol and method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underwater communication apparatus and method, and in particular, to seamless underwater communication between divers by using a seamless Delay Tolerant Network (DTN) protocol. A communication device and a method for underwater communication thereof.

Divers generally work and work in poor underwater environments, so underwater communication between them is just as important as wetsuits. In diver networks, safety problems such as depth, tides, and floats can occur from time to time, so real-time and reliable communication between divers is essential.

Conventionally, when divers are underwater, it is difficult to secure a watch due to underwater turbidity and can be moved to a dangerous area according to the current. Therefore, depending on the situation, it is not possible to recognize the status or emergency situation of fellow divers in a timely manner, causing a safety accident. There is this.

In addition, the communication between the divers is often made by hand, there is a problem that the conversation between divers in the water is limited.

Accordingly, in the technical field, there has been a demand for the development of a technology that enables the real-time and reliable underwater communication by forming a diver network for safe underwater activities of divers.

Republic of Korea Patent No. 10-1296744 Republic of Korea Patent No. 10-1475926 Republic of Korea Patent Publication No. 10-2013-0030970

The present invention is an underwater communication apparatus capable of supporting real-time and reliable communication while supporting the mobility of divers in a diver network through a seamless DTN protocol in an underwater environment in response to the problems of the prior art and the demand of technology development and Its purpose is to provide the communication method.

In addition, the present invention provides a P2P-based handover (suitable for the underwater environment) to ensure the mobility of divers underwater communication device using a seamless DTN protocol to enable seamless communication (seamless) and its communication There is another purpose in providing a method.

The present invention also provides an underwater communication apparatus and a communication method for minimizing overhead and communication traffic through a compression scheme using a lightweight extension header and an address scheme for a seamless DTN protocol in a header of an existing underwater communication protocol. There is another purpose to provide.

In the underwater communication device using the seamless DTN protocol according to an embodiment of the present invention, in the underwater communication device which is mounted on a plurality of divers and constitutes a diver network (DN), it is connected to a lower data link layer and connected to an external device. A data link abstract layer providing an interface of the; And a DTN function that stores and retransmits the transmitted data in a buffer to perform DTN function for underwater communication, and forms a network topology that forms and manages a DN topology based on underwater MANET. The management unit, the environment information collection and management unit for collecting and managing the environment information by periodically analyzing the packets received through the overhearing of multiple communication media, the environment for storing the environment information collected and managed Selecting the data link layer through the machine learning based on the surrounding situation information collected and stored in the information storage unit, the surrounding situation information collection and management unit and the surrounding situation information storage unit, and establishing an operation policy And an S-DTN layer including an operation unit. It includes.

In an embodiment of the present invention, the data link abstract layer may include: a data link layer common interface for providing a unified common standard interface for accessing multiple interfaces to multiple communication media by a communication protocol operated in the diver network (DN); A data link layer common function unit providing redundant functions of the protocol of the data link layer for the multiple communication media as a common function; And a data link layer adapter supporting access to multiple communication media through the data link layer.

In the present invention, when the S-DTN layer receives a data transmission request from a preset external device, the data link layer selection and operation unit may satisfy a real-time restriction on the transmission of the data based on the surrounding situation information. After selecting a communication medium, the data transmission request is transmitted to the data link abstract layer through the selected multiple communication mediums.

In the present invention, the data link abstraction layer generates a packet suitable for the selected multi-communication medium and transmits the packet to an external device when the transmission request of the data is received.

In the present invention, the S-DTN layer performs a fragmentation (fragmentation) when the size of the data is larger than the maximum transmission size (MTU) of the selected multi-communication medium after receiving the transmission request of the data The data link abstraction layer transmits the packet to the link abstraction layer, and generates a packet suitable for the selected multiple communication media according to the fragmented data and transmits the packet to an external device.

In the present invention, when the S-DTN layer receives the packet from the outside, the S-DTN layer reassembles the fragmented data included in the packet and restores the original data.

In the present invention, the surrounding information collection and management unit the number of packets received for each time zone of the multi-communication medium, error information of the packet, the reception rate and error rate information for various frequency bands in the case of the same communication medium, the surrounding piggybacked on the receiving packet Collect the information of the diver network (DN) through the context information header to store and update the surrounding situation information storage unit.

In the present invention, the S-DTN layer performs a compression and decompression function of a cluster head selector or a lightweight address system suitable for a diver network (DN) to select cluster heads in a plurality of clusters when the diver network (DN) topology is formed. It may further include at least one of the lightweight address system compression and recovery unit.

In the present invention, the lightweight address system compression and recovery unit provides an address system that is compatible between the underwater and the ground IoT for interworking between the underwater IoT (IoUT) and the ground IoT.

In the present invention, the S-STN layer is a lightweight P2P-based handover function to perform a handover function to enable seamless underwater communication when a diver in a first cluster moves to a second cluster in the diver network (DN). It may further include wealth.

In addition, the underwater communication method using the seamless DTN protocol according to an embodiment of the present invention, comprising: configuring a diver network (DN) including a plurality of divers in the gateway and the cluster in the S-DTN layer; Collecting and storing a plurality of surrounding situation information through the data link abstraction layer; Selecting a multi-communication medium capable of satisfying a real-time constraint according to the transmission of the emergency message based on the stored surrounding situation information when the S-DTN layer receives an emergency message transmission request according to a risk detection from an external device; Transmitting, at the S-DTN layer, a request for transmission of the emergency message to the data link abstract layer; Generating a packet suitable for the selected multiple communication media in response to the emergency message and transmitting the generated packet to the outside through the multiple communication media in the data link abstract layer; It includes.

In the present invention, the step of collecting and storing the surrounding situation information, the number of packets received for each time zone of the multi-communication medium, the error information of the packet, the reception rate and error rate information for various frequency bands, the reception packet in the same communication medium Collects the information of the diver network (DN) through the piggybacked surrounding situation information expansion header and stores and updates the surrounding situation information storage unit.

In addition, the underwater communication method using the seamless DTN protocol according to another embodiment of the present invention, comprising: configuring a diver network (DN) including a plurality of divers in the gateway and the cluster in the S-DTN layer; Collecting and storing a plurality of surrounding situation information through the data link abstraction layer; Selecting a multi-communication medium capable of reliable transmission according to the transmission of the picture / video based on the stored surrounding situation information when the S-DTN layer receives a picture / video transmission request from an external device; Performing fragmentation of the photo / image by comparing the maximum transmission size (MTU) of the selected multi-communication medium with the size of the photo / image in the S-DTN layer; Transmitting a transmission request of the fragmented photo / video to the data link abstract layer by the S-DTN layer; And generating, by the data link abstraction layer, a packet corresponding to the selected multi-communication medium corresponding to the fragmented picture / video and transmitting the generated packet to an external device through the multi-communication medium.

In the present invention, the fragmentation is performed when the size of the picture / video is larger than the MTU of the selected multiple communication medium.

In the present invention, after the step of transmitting the packet to the external device, when receiving the packet at the external device, the original picture by reassembling the fragmented picture / video included in the packet in the S-DTN layer of the external device The method may further include restoring the image.

In addition, the underwater communication method using the seamless DTN protocol according to another embodiment of the present invention, comprising: configuring a diver network (DN) including a plurality of divers in the gateway and the cluster in the S-DTN layer; Collecting and storing a plurality of surrounding situation information through the data link abstraction layer; Performing communication with other divers in the first cluster at a data link abstract layer of the underwater communication device mounted on the first diver; During the communication, as the first diver moves from the first cluster to the second cluster, the data link abstraction layer loses communication with the first cluster head of the first cluster and the second cluster of the second cluster. Sensing movement between the first and second clusters through communication with the head; Notifying the S-DTN layer from the data link abstract layer to the received information through the first and second cluster movement detection and communication start; Storing the informed reception information in the S-DTN layer and recognizing information of a second cluster to which the first diver currently moves based on the surrounding situation information stored in the surrounding situation information storage unit; Transmitting a join request for the second cluster from the S-DTN layer to the second cluster head; The second cluster head notifying the DN gateway corresponding to the second cluster head of updating cluster information and transmitting a join approval of the second cluster to the S-DTN layer; And the first diver communicating with other divers in the second cluster.

According to the present invention, the safety of divers is guaranteed by enabling real-time and reliable underwater communication in a network between divers who are underwater.

In addition, according to the present invention it is possible to contribute to the activation of the relevant market by enabling reliable underwater communication between divers.

In addition, according to the present invention, through the real-time reliability and mobility features of the seamless DTN protocol, it is possible to mitigate and overcome the risks and limitations of activities that divers can experience underwater.

Furthermore, the present invention enables the activation of various application domains by applying the seamless DTN protocol to the underwater IoT environment.

1 is a diagram illustrating a seamless DTN based diver network according to an embodiment of the present invention;
2 is a block diagram illustrating an underwater communication apparatus using a seamless DTN protocol according to an embodiment of the present invention;
3 is a flow chart showing an underwater communication method using the seamless DTN protocol according to an embodiment of the present invention;
4 is a flowchart illustrating an underwater communication method using a seamless DTN protocol according to another embodiment of the present invention;
5 is a flowchart showing a method of underwater communication using the seamless DTN protocol according to another embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to the accompanying drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used to refer to the same components as much as possible, even if displayed on different drawings. In addition, in describing the embodiments of the present invention, when it is determined that a detailed description of a related well-known configuration or function disturbs the understanding of the embodiment of the present invention, the detailed description thereof will be omitted.

In addition, in describing the components of the embodiments of the present disclosure, terms such as first, second, A, B, (a), and (b) may be used. These terms are only to distinguish the components from other components, and the nature, order or order of the components are not limited by the terms. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected or connected to that other component, but there is another component between each component. It will be understood that may be "connected", "coupled" or "connected".

1 is a block diagram of a seamless DTN based diver network according to an embodiment of the present invention. Referring to FIG. 1, a seamless DTN-based diver network (DN, Diver Network) according to the present invention includes a plurality of divers 10, a plurality of gateways 20, a communication network 30, and a DN service management server 40. It is configured to include. At this time, the diver 10 may be an underwater robot such as an AUV (Autonomous Underwater Vehicle) or a ROV (Remotely Operated Vehicle) as a subject who moves and moves underwater. In addition, it means a device that performs various functions while being attached or worn by a diver, diver, and the like. In the present embodiment, these are collectively referred to as divers for convenience of description.

DN network according to the present invention is preferably formed of a cluster-based structured diver network topology as shown in the figure. In the figure, some clusters of DN topologies are shown as an example, but the number thereof may be changed.

Some plurality of divers 10 in underwater communication with each other form a DN cluster 11. Each cluster 11 has a cluster head 10a, respectively. The cluster head 10a is set to one of the plurality of divers 10 included in the cluster 11. The cluster head 10a also communicates with other divers 10 while performing activities and tasks underwater, receives data, and transmits the data to the upper DN gateway 20 through underwater communication.

Each gateway 20 corresponds to at least one cluster 11. That is, the data is received from at least one cluster head 10a and transmitted to the DN service management server 40 on the ground through the communication network 30. The DN service management server 40 processes and manages the data received from the divers 40 underwater in the ground.

Each of the divers 10 is guaranteed for mobility. Thus, as shown in the figure 'move' may move from the original DN cluster 11 to its own DN cluster (11). The drawing shows an example in which the diver # 1.1.4 moves from the DN cluster # 1.1 to the DN cluster # 1.2 and then to the DN cluster # 2.1.

Here, the divers 40 are each provided with an underwater communication device for transmitting and receiving data through underwater communication. These underwater communication devices transmit and receive data between each other and between the DN gateway 20 using a seamless DTN protocol. In this case, the underwater communication apparatus according to the present invention is characterized in that the seamless real-time and reliable underwater communication is possible when transmitting data. Underwater communication applied to the present embodiment uses a variety of multiple communication media. For example, communication media such as sound waves, visible light, magnetic fields, and low frequencies are applied.

2 is a block diagram illustrating an underwater communication apparatus using a seamless DTN protocol according to an exemplary embodiment of the present invention. Referring to FIG. 2, the underwater communication device 100 (hereinafter, referred to as an underwater communication device for convenience) using the seamless DTN protocol according to the present invention includes a data link abstract layer 110, a network layer 120, and a transmission layer 130. ), S-DTN layer 140 and the cross-layer interface 150 is configured.

The underwater communication device 100 is connected to the lower data link layer 210 and the data link layer 210 is responsible for communication with the ground / underwater communication model 220. Such communication modems may include sound waves, visible light, low frequency, magnetic field modems, and the like. In addition, the underwater communication device 100 is connected to the upper diver network (DN) application layer 230.

The data link abstract layer 110 is a layer that provides an interface with the underlying data link layer 210. The data link abstract layer 110, the data link layer common functional unit 112, and the data link layer And an adapter 113. The data link layer common interface 111 is a unified common standard interface for a communication protocol operating in a diver network (DN) to access various multiple interfaces for multiple communication media (for example, sound wave, visible light, magnetic field, low frequency, etc.) standard interface). The data link layer common function unit 112 minimizes waste of resources by providing a redundant function of a protocol of the data link layer 210 for various multiple communication media as a common function as described above. The data link layer adapter 113 supports access to various media through the data link layer 210.

The network layer 120 may be selectively applied as a light weight network layer suitable for the underwater diver network (DN), and may include only minimal basic functions or delegate functions to the S-DTN layer 140.

The transport layer 130 may also be selectively applied as a lightweight network layer suitable for the DN, and it may be possible to include only minimal basic functions or delegate functions to the S-DTN layer 140.

The S-DTN layer 140 includes a DTN function unit 141, a network topology forming and managing unit 142, a cluster head selecting unit 143, a lightweight address system compression and restoration unit 144, and a surrounding situation information collecting and managing unit ( 145, a peripheral situation information storage unit 146, a data link layer selection and operation unit 147, and a lightweight P2P based handover function unit 148.

The DTN function unit 141 performs a lightweight DTN function for ensuring communication in the underwater environment. The DTN function unit 141 stores and retransmits a message transmitted from the transmitting end in a buffer using a store and forward mechanism, and then acknowledges the message. Do this.

The network topology formation and management unit 142 is overloaded and resources to adopt and operate a separate topology for the Underwater Mobile Ad-hoc Network (MANET) in the data link layer 210, network layer 120, transport layer 130, etc. In order to minimize waste, the S-DTN layer 140 performs a function of forming and managing a DN topology based on an underwater MANET.

The cluster head selecting unit 143 selects a cluster head in each cluster when forming a cluster-based DN topology.

Lightweight address system compression and restoration unit 144 is a configuration that performs the compression and recovery function of the lightweight address system suitable for the diver network (DN), underwater for the interworking between the Internet of Things (IoUT, Internet of Underwater Things) and the ground IoT And to support the interoperable address system between the ground IoT. In the case of the IPv6 system used in the terrestrial IoT, it is impossible to apply the address system to the underwater environment. Of course, on the ground, the Compression Scheme for IPv6 addressing system is applied in consideration of the operation in the constrained environment such as 6LoWPAN, but this also has a limitation in applying it directly to the underwater environment.

To overcome this, based on the 6LoWPAN compressor method, it reflects the environmental factors suitable for the diver network (eg, the number of divers in the cluster, the identifier length, the topology structure, etc.), omitting unnecessary parts and reducing the number of bits in the field. To further improve the compression efficiency.

The surrounding situation information collection and management unit 145 collects, manages, and stores surrounding situation information, which periodically analyzes packets received through overhearing of multiple communication media in the water. Collects LQI (Link Quality Indicator) information such as the number of packets received in each time slot of the multi-communication medium, error information of the packet, reception rate and error rate for various frequency bands even in the same medium, and transmits the information to the peripheral information storage unit 146. Save and update. In addition, it collects the diver network (DN) -related information (eg, cluster, cluster head, diver, etc.) through the surrounding information expansion header piggybacked in the reception packet to be stored and updated in the surrounding information storage unit 146 as well. .

The data link layer selection and operation unit 147 is a real-time and reliable through machine learning based on the surrounding situation information collected, stored and updated by the surrounding situation information collection and management unit 145 and the surrounding situation information storage unit 146. It performs the function of selecting the appropriate multiple data link layer and establishing the operation policy for underwater communication. The machine learning may apply a deep learning algorithm, for example.

In addition, the data link layer selection and operation unit 147 analyzes the latest ambient situation information in case of real-time emergency communication to select a multi-data link layer and multiple frequency bands that can satisfy the real-time constraints to perform communication. .

In addition, in the case of reliable communication, the data link layer selection and operation unit 147 analyzes the latest ambient situation information and selects a multiple data link layer and multiple frequency bands capable of reliable data transmission to perform communication. .

Further, when data division is required, the data link layer selection and operation unit 147 performs fragmentation of data in consideration of the maximum transmission unit (MTU) size of the multiple data link layer at the transmitting side. Allows transmission to the medium. Therefore, even if some packet loss occurs on the receiving side, reliable communication is possible by reassembling using packets received from other media.

The lightweight P2P based handover function unit 148 performs a lightweight P2P based handover function suitable for a diver network (DN). This is to perform a handover function so that seamless underwater communication is possible even if a diver belonging to a cluster in the DN moves to another cluster.

In addition, the lightweight P2P-based handover function unit 148 is configured to form a lightweight P2P-based overlay network, that is, a diver network (DN) in the network topology forming and managing unit 142 and perform a lightweight P2P-based handover when the diver moves. do.

In addition, in the case of the diver moving from one cluster to another cluster, the current situation is moved by utilizing the surrounding context information of the piggybacked extended header of the plurality of receiving packets received through the multiple communication media through the surrounding situation information collecting and managing unit 145. Recognize clusters and perform handovers.

Meanwhile, the S-DTN layer 140 may receive a message or data from an external device such as various sensors, cameras, smart devices, and the like. Such messages or data may preferably be emergency messages or emergency data informing the diver of danger. That is, in the present exemplary embodiment, in order to detect an emergency situation or an emergency situation, a risk may be detected through various sensors, and an image may be captured and transmitted as an emergency situation through a camera.

Referring to the communication process of the underwater communication device 100 having such a configuration, if the underwater communication device 100 mounted on the diver is added to the diver network (DN) to enter a specific cluster network topology forming and management unit 142 Performs the diver network formation process. The surrounding situation information collection and management unit 145 continuously collects, analyzes and updates various surrounding situation information collected through the data link abstract layer 110.

At this time, if a risk is detected from a preset external device mounted on a specific diver or a picture / image is taken, the S-DTN layer 140 requests a risk detection emergency message or a picture / image transmission. Then, the data link layer selection and operation unit 142 selects a multi-communication medium that can satisfy real-time constraints on emergency message or picture / video transmission based on the surrounding situation information according to the transmission request. In addition, an emergency message or a picture / video transmission request is made to the data link abstract layer 110 through the selected multiple communication media.

In this case, when the transmission target is a picture / video, the S-DTN layer 140 may perform fragmentation of the picture / video by considering the MTU of the multi-communication medium selected as described above. The picture / video transmission request is then a fragmentation picture / video data transmission request.

The data link abstract layer 110 generates a packet suitable for the selected multiple communication medium and transmits the packet to the underwater communication device 100 of the cluster head or another diver through the selected multiple communication medium. This transmission may be done by broadcasting. Underwater communication apparatus 100 of another diver to receive the packet through the data link abstract layer (110).

Accordingly, as soon as the data link abstract layer 110 receives the received packet, the data link abstract layer 110 outputs an alarm through an external device mounted on the diver so that the diver knows the occurrence of an emergency and notifies the support request. As soon as the clusterhead receives the packet, the cluster head selects the neighboring diver, the clusterhead and / or the DN gateway to propagate using the context information and transmits the packet to the selected target.

If a packet including fragmented photo / image data is received, the fragmented photo / image data in the S-DTN layer 140 is reassembled and restored to the original photo / image, and then the restored photo / Instruct the diver to request assistance by sending a video.

3 is a flowchart illustrating an underwater communication method using a seamless DTN protocol according to an embodiment of the present invention. Referring to FIG. 3, the underwater communication method using the seamless DTN protocol according to an embodiment of the present invention provides a real-time and reliable packet transmission process to notify a neighboring diver when a danger is detected.

First, a process of forming a diver network DN is performed between the DN gateway 20 and the plurality of divers 10 in the cluster (S101). The DN formation process is performed in the network topology formation and management unit 142 of the underwater communication device 100 of the diver. In the DN forming process, for example, a plurality of divers belonging to a cluster, a cluster head decision among a plurality of divers, and a DN gateway decision corresponding to the cluster are made.

Subsequently, the underwater environment information collection and management unit 145 continuously collects, analyzes and updates various surrounding situation information collected through the data link abstract layer 110 (S103). The analysis and update results are stored in the surrounding situation information storage unit 146.

Subsequently, when the danger of the diver is detected from an external device (eg, a danger detection sensor) mounted on the diver (S105), the external device transmits a request for transmitting a danger detection emergency message to the S-DTN layer of the underwater communication device 100 ( 140) (S107). Accordingly, the S-DTN layer 140 selects an appropriate multi-communication medium that can satisfy the real-time constraint on the transmission of the emergency message based on the surrounding situation information (S109). Then, the emergency message transmission request is transmitted to the data link abstract layer 110 through the selected multiple communication media (S111).

Then, the data link abstract layer 110 generates a packet suitable for the selected multi-communication medium (S113), and transmits the packet to the underwater communication device 100 and the cluster head of another diver (S115). This transmission may be made by broadcast, and the packet is transmitted to the S-DTN layer 140 through the data link abstract layer 110 of the underwater communication device 100 (S117). In addition, the S-DTN layer 140 transfers it back to the external device (S119). In response, the external device outputs an alert in response to the received packet (S121). These alerts allow divers to detect and assist neighboring divers in dangerous situations.

In addition, when the cluster head receives the packet as described above, the cluster head selects an adjacent diver, a cluster head, or a DN gateway to transmit the packet based on the surrounding situation information as described above (S123), and transmits the packet to the selected object (S123). S125).

Through this process, if a diver's danger occurs, the packet can be sent in real time to other divers, cluster heads, and DN gateways.

4 is a flowchart illustrating a method of underwater communication using a seamless DTN protocol according to another embodiment of the present invention. Referring to FIG. 4, in the underwater communication method using the seamless DTN protocol according to another embodiment of the present invention, a real-time and reliable packet transmission process for notifying a diver between neighboring divers when a picture or video according to a risk is taken To provide.

First, as in FIG. 3, a process of forming a diver network DN is performed between the DN gateway 20 and the plurality of divers 10 in the cluster (S201). Subsequently, the underwater environment information collection and management unit 145 continuously collects, analyzes and updates various surrounding situation information collected through the data link abstract layer 110 (S203). The analysis and update results are stored in the surrounding situation information storage unit 146.

Subsequently, when a picture or video (photo / video) is taken from an external device (for example, a camera) mounted on the diver (S205), the external device transmits the received picture / video transmission request to the underwater communication device 100 of the diver. S-DTN layer 140 of the transfer to (S207). Accordingly, the S-DTN layer 140 selects a multi-communication medium capable of reliable transmission of a picture / video transmission based on the surrounding situation information (S209). Then, the transmission request of the picture / video is transmitted to the data link abstract layer 110 through the selected multi-communication medium (S213).

In this case, if necessary prior to the request for transmitting the picture / video after step S209, it is also possible to selectively perform fragmentation of the picture / video data (S211). This is performed when the size of the photo / image data is larger by comparing the maximum transmission size (MTU) of the multi-communication medium configured in step S209 with the size of the photo / image data. This is because a picture / video size larger than the MTU of a multi communication medium cannot be sent all at once. This is because in an emergency situation, when only a part of the picture / video is transmitted or the data is broken, the emergency situation may not be properly informed. Therefore, in another embodiment, when the fragmentation operation is performed as in step S211, the request for transmission of the fragmented picture / video is transmitted to the data link abstract layer 110 in step S213.

Thereafter, the data link abstract layer 110 generates a packet suitable for the selected multi-communication medium (S215), and transmits the packet to the underwater communication device 100 of another diver (S217). This transmission can be done by broadcast. Subsequently, a picture / video is transmitted to the S-DTN layer 140 through the data link abstract layer 110 of the underwater communication device 100 of another diver (S219). The S-DTN layer 140 transfers it back to the external device (S223). Accordingly, the external device may output a picture / video in response to the received packet and may also output an alarm. Other divers will be able to identify these photos / videos so they can detect and assist other divers in danger.

In this case, when receiving the packet including the fragmented picture / video in the S-DTN layer 140 as in the other embodiment, in step S223 before transmitting the packet to the external device S-DTN layer 140 After reassembling the fragmented picture / video in the original image is assembled (S221), it is transferred to the external device (S223).

In addition, when the cluster head receives the packet as described above, the cluster head may select a neighbor diver, a cluster head, or a DN gateway to transmit the packet based on the surrounding situation information as described above, and transmit the packet to the selected target.

Through this process, if a diver's danger occurs, the packet can be sent in real time to other divers, cluster heads, and DN gateways.

5 is a flowchart illustrating a method of underwater communication using a seamless DTN protocol according to another embodiment of the present invention. Referring to FIG. 5, in the underwater communication method using the seamless DTN protocol according to another embodiment of the present invention, when the first diver moves from the first cluster to another second cluster as shown in FIG. Represents a communication process between underwater communication devices for handover.

First, a process of forming a diver network DN is performed between the DN gateway 20 and the plurality of divers 10 in the cluster as in FIGS. 3 and 4 (S301). Subsequently, the underwater environment information collection and management unit 145 continuously collects, analyzes and updates various surrounding situation information collected through the data link abstract layer 110 (S303). The analysis and update results are stored in the surrounding situation information storage unit 146.

While performing communication with other divers in the first cluster in the data link abstract layer 110 of the underwater communication device 100 mounted on the first diver (S305), the first diver receives the second cluster from the first cluster. In operation S307, the data link abstraction layer 110 detects the communication disconnection with the first cluster head and the movement of the cluster by receiving information with the second cluster head.

Accordingly, the data link abstract layer 110 notifies the S-DTN layer 140 of the reception information through the inter-cluster movement detection and communication start (S309). Then, the surrounding situation information collection and management unit 145 of the S-DTN layer 140 stores the received information in the surrounding situation information storage unit 146 (S311), and the lightweight P2P based handover function unit 148. In operation S313, the first diver recognizes information about the second cluster to which the first diver has moved based on the surrounding situation information stored in the surrounding situation information storage unit 146.

Thereafter, the S-DTN layer 140 of the underwater communication apparatus 100 of the first diver transmits the cluster join request to the second cluster head of the second cluster (S315). Then, the second cluster head notifies the DN gateway corresponding to the cluster information update (S317), and transmits the cluster join approval to the S-DTN layer 140 (S319). This allows the first diver to communicate with other divers in the second cluster.

Subsequently, the first cluster head notifies the S-DTN layer 140 of the second diver to update the corresponding cluster information (S321), and the first diver who moves to the second cluster communicates with other divers in the second cluster. It is made (S323).

As described above, the present invention provides an underwater communication protocol that enables real-time and reliable communication by forming a diver network (DN) for safe underwater activities between divers and performs underwater communication based on these protocols. An underwater communication device and a communication method thereof are provided. In particular, the present invention shows that a seamless underwater communication between divers is possible by providing a real-time emergency message transmission method, a real-time reliable message transmission method, and a divers handover communication method.

In the foregoing description, all elements constituting the embodiments of the present invention are described as being combined or operating in combination, but the present invention is not necessarily limited to the embodiments. In other words, within the scope of the present invention, all of the components may be selectively operated in combination with one or more. In addition, the terms "comprise", "comprise" or "having" described above mean that the corresponding component may be inherent unless specifically stated otherwise, and thus excludes other components. It should be construed that it may further include other components instead. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. Terms used generally, such as terms defined in a dictionary, should be interpreted to coincide with the contextual meaning of the related art, and shall not be interpreted in an ideal or excessively formal sense unless explicitly defined in the present invention.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

10: diver
10a: cluster head
11: cluster
20: DN gateway
30: communication network
40: DN service management server
110: data link abstract layer
111: common interface of data link layer
112: common function part of data link layer
113: data link layer adapter
120: network layer
130: transport layer
140: S-DTN layer
141: DTN function part
142: Network Topology Formation and Management Department
143: cluster head selection unit
144: Lightweight address system compression and restoration unit
145: Collection and management of surrounding situation information
146: surrounding information storage
150: cross-layer interface
210: data link layer
220: ground / underwater communication modem
230: diver network application layer

Claims (16)

In the underwater communication device constituting the diver network (DN),
DTN function for storing and retransmitting data in buffer to perform DTN function for underwater communication, network topology formation and management unit for forming and managing DN topology based on underwater MANET, at least Peripheral context information that periodically analyzes packets received through two or more communication media, wherein the peripheral context information includes communication status related information and the DN related information through the communication media At least one communication medium among a plurality of data link layers corresponding to the communication media through the information collection and management unit, the environment information storage unit for storing the environment information, the machine learning based on the environment information based on the environment information Data link layer selection and operation policy selection and An S-DTN layer including an operation unit; And
A data link abstract layer providing an interface between the S-DTN layer and the data link layers and processing the data according to a communication protocol corresponding to the selected data link layer;
Underwater communication device using a seamless DTN protocol comprising a.
The method of claim 1,
The data link abstract layer,
A data link layer common interface providing a unified common standard interface for the data link layers;
A data link layer common function unit providing redundant functions of communication protocols of the data link layers as a common function; And
And a data link layer adapter to support access to the communication media through the data link layers.
The method of claim 1,
The S-DTN layer,
When receiving a data transmission request from a preset external device, the data link layer selection and operation unit selects a communication medium that satisfies the real-time constraints on the data transmission among the communication media based on the surrounding situation information. Underwater communication device using a seamless DTN protocol for transmitting the data transmission request to the data link abstract layer through the selected communication medium.
The method of claim 3,
The data link abstract layer,
When the transmission request of the data is received, generates a packet suitable for the selected communication medium and transmits the packet to the outside, the underwater communication device using a seamless DTN protocol.
The method of claim 4, wherein
The S-DTN layer,
When the size of the data is larger than the maximum transmission size (MTU) of the selected communication medium, after performing fragmentation (fragmentation) and transmits the transmission request of the fragmented data to the data link abstract layer,
The data link abstract layer,
And generating a packet suitable for the selected communication medium according to the fragmented data to transmit the packet to the outside.
The method of claim 5,
The S-DTN layer,
And receiving the packet from the outside, reassembling the fragmented data contained in the packet to restore the original data.
The method of claim 1,
The communication state related information,
At least one of the number of received packets per time slot, packet error information, frequency band reception rate and error rate information for the communication medium,
DN related information,
And at least one of a cluster, a cluster head, and diver related information for the DN.
The method of claim 1,
The S-DTN layer,
Further comprising at least one of a cluster head selecting unit for selecting a cluster head in a plurality of clusters when forming the DN topology, or a lightweight addressing system compression and restoration unit for performing a compression and restoration function of the lightweight addressing system suitable for the DN, Underwater communication device using seamless DTN protocol.
The method of claim 8,
The lightweight address system compression and recovery unit,
Underwater communication device using the seamless DTN protocol, which provides an interoperable address system between the underwater and the ground IoT for interworking between the underwater IoT (IoUT) and the ground IoT.
The method of claim 9,
The S-DTN layer is,
And a lightweight P2P based handover function for performing a handover function to enable seamless underwater communication when the diver in the first cluster moves to the second cluster in the DN.
Configuring a diver network (DN) including a gateway and a plurality of divers in a cluster at the S-DTN layer;
Collecting and storing a plurality of surrounding situation information through the data link abstraction layer;
When the S-DTN layer receives an emergency message transmission request according to a risk detection from an external device, a communication medium capable of satisfying real time constraints of the emergency message transmission among a plurality of communication media based on the stored surrounding situation information Selecting a;
Transmitting, at the S-DTN layer, a request for transmission of the emergency message to the data link abstract layer; And
Generating a packet suitable for the selected communication medium in response to the emergency message and transmitting the generated packet to the outside through the selected communication medium in the data link abstract layer;
Underwater communication method using a seamless DTN protocol comprising a.
The method of claim 11, wherein the collecting and storing the surrounding situation information comprises:
Seamless DTN for collecting, storing and updating the information of the DN through time slots of the communication media, packet error information, frequency band reception and error rate information, and surrounding situation information expansion header piggybacked on the reception packet. Underwater communication method using protocol.
Configuring a diver network (DN) including a gateway and a plurality of divers in a cluster at the S-DTN layer;
Collecting and storing a plurality of surrounding situation information through the data link abstraction layer;
When the S-DTN layer receives a request for transmitting a picture / video from an external device, the S-DTN layer selects a communication medium capable of reliable transmission according to the picture / video transmission among a plurality of communication media based on the stored surrounding situation information. step;
Performing fragmentation of the photo / image by comparing the maximum transmission size (MTU) of the selected communication medium with the size of the photo / image in the S-DTN layer;
Transmitting, by the S-DTN layer, the transmission request of the fragmented picture / video to the data link abstract layer; And
Generating a packet corresponding to the selected communication medium in response to the fragmented picture / video in the data link abstract layer and transmitting the generated packet to the external device through the selected communication medium;
Underwater communication method using a seamless DTN protocol comprising a.
The method of claim 13,
The fragmentation is performed when the size of the picture / video is larger than the MTU of the selected communication medium, underwater communication method using a seamless DTN protocol.
The method of claim 13,
After transmitting the packet to the external device,
Receiving the packet from the external device, the S-DTN layer of the external device further comprises the step of reassembling the fragmented picture / video contained in the packet to restore the original picture / video, using the seamless DTN protocol Underwater communication method.
Configuring a diver network (DN) including a gateway and a plurality of divers in a cluster at the S-DTN layer;
Collecting and storing a plurality of surrounding situation information through the data link abstraction layer;
Performing communication with other divers in the first cluster at a data link abstract layer of the underwater communication device mounted on the first diver;
During the communication, as the first diver moves from the first cluster to the second cluster, the data link abstraction layer loses communication with the first cluster head of the first cluster and the second cluster of the second cluster. Sensing movement between the first and second clusters through communication with the head;
Notifying the S-DTN layer from the data link abstract layer to the received information through the first and second cluster movement detection and communication start;
Storing the informed reception information in the S-DTN layer and recognizing information of a second cluster currently moved by the first diver based on the surrounding situation information stored in the surrounding situation information storage unit;
Transmitting a join request for the second cluster from the S-DTN layer to the second cluster head;
The second cluster head notifying the DN gateway corresponding to the second cluster head of updating cluster information and transmitting a join approval of the second cluster to the S-DTN layer; And
And said first diver communicating with other divers in said second cluster.

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