KR102128946B1 - Network structure for the scene of a fire - Google Patents

Abstract

The present invention relates to a network structure for reliable information transmission at a scene of a fire, which applying a routing protocol of multiple copy type simultaneously with using a delay and disruption tolerant network (DTN) instead of TCP/IP to smoothly transfer information between firefighters and between the firefighter and a control center and stably search for the location of a person who requires rescue. According to the present invention, the network structure comprises: a firefighter portable terminal, location tracking safety shoes of a firefighter, and the control center. The firefighter portable terminal comprises: a first function positioning a mobile communication terminal of a person, who requires rescue, through RSSI and BLE direction information received from other firefighter portable terminals and the mobile communication terminal of the person who requires rescue; and a second function determining and correcting the relative azimuth antenna of a firefighter who enters the scene of a fire based on an RF anchor and the location of the firefighter, wherein WLAN/BLE direction finding technology is applied to the first function and an inter-firefighter azimuth determination technology based on the RF anchor for radio tracing.

Description

Network structure for reliable transmission of information in the fire field

The present invention uses a DTN (Delay and Disruption Tolerant Network) instead of TCP/IP and applies a multi-copy routing routing protocol to ensure reliable and reliable information transfer between firefighters and between firefighters and command and control stations. At the same time, the present invention relates to a network structure for reliable information transmission in a fire site that enables a stable search for the location of a requestor.

The TCP/IP protocol basically has a continuous and bidirectional end-to-end communication path, and is designed assuming a short round-trip time, high transmission reliability, and symmetric data transmission/reception rates.

However, the heat (heat energy) in the fire scene interferes with the radio communication signal very much, and it may become as if the reinforcing bar is blocked.

In other words, because the communication path between end-to-end is frequently disconnected and has low transmission reliability in a fire scene, reliable data transmission cannot be guaranteed using traditional methods such as TCP/IP.

That is, the fire site is an environment in which it is difficult to secure a field of view due to smoke, but as described above, communication between the portable terminals of the firefighter is frequently disconnected, so data transmission and reception is very unstable, and communication between the portable terminal of the firefighter and the command control computer of the command center This frequent disconnection makes data transmission and reception very unstable. Therefore, it is difficult to identify the location of firefighters and escape routes.

Incidentally, in the case of a fire scene, the traditional network method such as TCP/IP does not facilitate communication of information between firefighters and between firefighters and command and control, and it is difficult to find the location of the requestor.

Korean Patent Publication No. 10-2009-0097842 (published on September 16, 2009), “Fireman's location tracking method and management system” Korean Registered Patent No. 10-1610108 (announced on April 11, 2016), “Ad-hoc network system for high temperature avoidance and routing path setting method” Korean Registered Patent No. 10-1651894 (announced on August 29, 2016), “Fire management method on the network using intelligent fire extinguishing tool, intelligent fire extinguishing tool and management server used for this”

In an embodiment of the present invention, a multi-copy routing routing protocol is applied at the same time using a DTN (Delay and Disruption Tolerant Network) instead of TCP/IP, and information transmission between the firefighters and between the firefighters and the command and control center is stable and reliable. It provides a network structure for reliable information transmission at the fire site, which enables it to stably search for the location of the requesting helper.

The network structure for reliable information transmission at a fire site according to an embodiment of the present invention is carried by a firefighter, and detects wireless communication information of the mobile communication terminal 10 carried by a requestor at the fire site, and moves Displays the location information of the communication terminal 10, and is equipped with artificial intelligence hardware 110 for signal processing in the terminal, wherein the artificial intelligence hardware 110 includes a communication module 111 between terminals, and a command control communication module 113. And a signal processing processor 114, and at the same time, an application processor that provides a multi-signal pattern collection function based on the firefighter's portable terminal 100 and a 3D precision positioning platform interworking function through data transmission and reception with the signal processing processor 114. A firefighter's portable terminal 100 including 115, worn by the firefighter, and equipped with an inertial sensor 210 to provide a self-position tracking function of the firefighter based on the inertial sensor 210, In case of emergency, the firefighter's location tracking safety boots 200 having the shortest return path guidance display function and the location information of the firefighter's portable terminal 100 are received, and the inertial sensor 210 of the firefighter's location tracking safety boots 200 Firefighter location tracking software using the signal of the firefighter and the firefighter's route search software for the search of the firefighter's request or for the safety return of the firefighter is mounted, and the firefighter location tracking software is determined based on the inertial sensor 210. It includes a command control computer 300 that tracks the indoor location using the walking characteristics of a circle, and provides an exploration route for performing a firefighter's mission through the firefighter's route search software, and includes the inertial sensor 210. By providing a single inertial sensor-based gait navigation system, it minimizes constraints due to sensor characteristics, considers the firefighter's motion based on learning, and provides an estimated position correction function using movement information, and provides a firefighter position monitoring system. , Conducting monitoring of the location of firefighters and the location of requesters, and possible directions or changes through route planning algorithms It provides a display function, and the firefighter may be capable of visualizing three types of information: a terminal UI, a helmet, and an air respirator.

According to an embodiment of the present invention, while using a multi-copy routing routing protocol using DTN (Delay and Disruption Tolerant Network) instead of TCP/IP, information transmission between the firefighters and between the firefighters and the command and control center is stable. It can be done reliably and at the same time it is possible to stably search for the position of the requestor.

1 is a network structure for reliable information transmission in a fire site according to an embodiment of the present invention
2 is a block diagram illustrating the configuration of a portable terminal of a firefighter in a network structure for reliable information transmission in a fire scene according to an embodiment of the present invention
3 is a diagram conceptually illustrating the processing action of the artificial intelligence hardware mounted on the portable terminal of the firefighter according to FIG. 2;
4 is a configuration diagram illustrating a location tracking system of a command and control computer in a network structure for reliable information transmission in a fire site according to an embodiment of the present invention
5 is a view showing an example of monitoring the position of the command and control computer in a network structure for reliable information transmission in a fire site according to an embodiment of the present invention
6 is a view showing an example of presenting the exploration hardness of the command control computer in the network structure for reliable information transmission in the fire site according to an embodiment of the present invention
7 is a diagram illustrating the counterpart angle measurement of the requestor and the correction of the Gyro measurement value of a firefighter in a network structure for reliable information transmission in a fire site according to an embodiment of the present invention.
8 is a diagram illustrating the direction detection of a requestor RF signal based on a super-directional antenna in a network structure for reliable information transmission in a fire site according to an embodiment of the present invention
9 is a diagram illustrating an RSSI-based requestor relative position estimation in a network structure for reliable information transmission in a fire site according to an embodiment of the present invention

The following detailed description of the present invention is an embodiment in which the present invention may be practiced and reference is made to the accompanying drawings shown as examples of the embodiment. These embodiments are described in detail so that those skilled in the art are sufficient to practice the present invention. It should be understood that the various embodiments of the invention are different, but need not be mutually exclusive. For example, the specific shapes, structures, and properties described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in relation to one embodiment. In addition, it should be understood that the position or arrangement of individual components within each described embodiment can be changed without departing from the spirit and scope of the invention.

Therefore, the following detailed description is not intended to be taken in a limiting sense, and the scope of the present invention is limited only by the appended claims, along with all ranges equivalent to those claimed by the claims if appropriately described. In the drawings, similar reference numerals refer to the same or similar functions throughout several aspects.

The terminology used in the present invention has been selected, while considering the functions in the present invention, general terms that are currently widely used have been selected, but this may vary according to the intention or precedent of a person skilled in the art or the appearance of new technologies. In addition, in certain cases, some terms are arbitrarily selected by the applicant, and in this case, their meanings will be described in detail in the description of the applicable invention. Therefore, the term used in the present invention should be defined based on the meaning of the term and the entire contents of the present invention, not a simple term name.

In the present invention, when a certain part “includes” a certain component, it means that the component may further include other components, not to exclude other components, unless otherwise stated. Also, “… Wealth”,　＂… The term “module” means a unit that processes at least one function or operation, which may be implemented in hardware or software, or a combination of hardware and software.

A network structure for reliable information transmission in a fire site according to an embodiment of the present invention will be described with reference to FIGS. 1 to 9.

1 is a network structure for reliable information transmission at a fire site according to an embodiment of the present invention, and FIG. 2 is a fire brigade in a network structure for reliable information transmission at a fire site according to an embodiment of the present invention. 3 is a diagram illustrating the configuration of the original portable terminal, and FIG. 3 is a diagram conceptually illustrating a processing operation of the AI hardware mounted in the portable terminal of the firefighter according to FIG. 2, and FIG. 4 is an embodiment of the present invention. In a network structure for reliable information transmission in a fire site according to the configuration diagram illustrating the location tracking system of the command and control computer, Figure 5 is a network for reliable information transmission in the fire site according to an embodiment of the present invention It is a view showing an example of monitoring the position of a command and control computer in a structure, and FIG. 6 shows an example of presenting an exploration hardness of a command and control computer in a network structure for reliable information transmission in a fire site according to an embodiment of the present invention FIG. 7 is a diagram illustrating a requester's counterpart angle measurement and a firefighter's Gyro measurement correction in a network structure for reliable information transmission at a fire site according to an embodiment of the present invention, and FIG. 8 is a diagram of the present invention FIG. 9 is a diagram illustrating the direction detection of a requestor RF signal based on a super-directional antenna in a network structure for reliable information transmission at a fire site according to an embodiment, and FIG. 9 is a reliable view at a fire site according to an embodiment of the present invention. This is a diagram illustrating the estimation of the relative position of the requestor based on RSSI in the network structure for information transmission.

As shown, the network structure for reliable information transmission at the fire site according to an embodiment of the present invention includes a firefighter's portable terminal 100, a firefighter's location tracking safety boots 200 and a command control computer 300. Including.

The firefighter's portable terminal 100 is carried by the firefighter, and the firefighter's portable terminal 100 detects the wireless communication information of the mobile communication terminal 10 carried by the requestor at the fire site, and the mobile communication terminal 10 Displays the location information. To this end, the portable terminal 100 of the firefighter is equipped with artificial intelligence hardware 110 for signal processing in the terminal for RF positioning, and the artificial intelligence hardware 110 includes a communication module 111 between terminals, and a command control communication module 113. ) And a signal processing processor 114, and at the same time, an application processor that provides a multi-signal pattern collection function and a 3D precision positioning platform interworking function based on the firefighter's portable terminal 100 through data transmission and reception with the signal processing processor 114. (115).

In other words, the firefighter's portable terminal 100 is a firefighter's location sensor tracking and command control interlocking technology applied.

And the firefighter's portable terminal 100 is applied with technologies such as hardware design for low power consumption, code optimization for power optimization, 3D precision positioning platform interlocking technology application, and fire safety equipment/command control system ICD design. In addition, the firefighter's portable terminal 100 is subjected to a data linkage test between mobile terminals, a data linkage test with a PDR terminal, and a test bed performance evaluation and test as a linkage test.

The firefighter's location tracking safety boots 200 are worn by firefighters, and equipped with an inertial sensor 210 to provide a firefighter's self-position tracking (PDR) function based on the inertial sensor 210 and return it to the shortest in an emergency. It has a route guidance display function.

In other words, the firefighter location tracking safety boots 200 can provide a location tracking system without restrictions such as pre-equipment and location information, and at the same time, provide a location monitoring function for firefighters and requesters.

The command and control computer 300 receives the location information of the firefighter's portable terminal 100, and uses the signal of the inertial sensor 210 of the firefighter's location tracking safety boots 200 to search for the location of the firefighter's location software and the firefighter's requestor. Also, the firefighter's route search software for safe return of the firefighter is mounted. The firefighter location tracking software tracks the indoor location using the walking characteristics of the firefighter identified based on the inertial sensor 210, and the command control computer 300 provides the firefighter's mission through the firefighter's route navigation software. It provides an exploration route for performance.

In addition, the network structure for reliable information transmission at the fire site in this embodiment provides a single inertial sensor-based walking navigation system, which minimizes constraints due to sensor characteristics and considers the operation of firefighters based on learning, It is possible to provide an estimated position correction function using the motion information. In addition, by providing a location monitoring system for firefighters, it is possible to provide firefighters' location and requestor location monitoring, and provide directions or directions through a route planning algorithm.

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In addition, the network structure for reliable information transmission at the fire site of the present embodiment enables a firefighter to visualize three types of information: a terminal UI, a helmet, and an air respirator.

The following describes the configuration that is the technical background of the above-described embodiment.

In order to realize an autonomous vehicle or a self-driving car, which is a recent issue, a connected car technology that provides a seamless connection to a vehicle in various environments is essential. Currently, the vehicle network (Vehicular network) technology for implementing a connected car is mainly composed of a single-hop wireless communication technology based on a transportation system infrastructure. Coverage of such single-hop communication is limited to the area where the transportation system infrastructure is built. Therefore, in order for the vehicle network to cover a wider area than the present, it is necessary to introduce a multi-hop communication, in which the vehicle itself functions as a mobile router and can transmit information remotely through transmission between vehicles. The multi-hop vehicle network has a number of challenging technical issues due to the high dynamic characteristics of the vehicle. Let's take a look at Delay-tolerant vehicular networking technology, a technology that can solve the connectivity between end nodes that can occur due to the high mobility of the vehicle network. To this end, we first analyze the technical background and key related technologies of delay-tolerant vehicle networking, and based on this, summarize technical issues that require future R&D.

Automobiles are one of the core infrastructures that support the current society. Automobiles have greatly contributed to the improvement of human mobility, but on the other hand, they also cause various social problems. The most important examples are the damage caused by automobile accidents and the congestion and pollution caused by large-scale automobiles. It is reported that more than 1 million people die annually in traffic accidents worldwide, and that the waste of oil in traffic jams is 3.9 billion gallons in the United States alone, and that the amount of greenhouse gases emitted from transportation is 14% of total greenhouse gas emissions. have. An autonomous vehicle is a technology that has recently attracted attention as a solution to this problem caused by automobiles. Thanks to these interests, autonomous vehicles have also attracted attention as the hottest issue at the world's two major electronics exhibitions, CES and MWC.

Self-driving cars are made up of several infrastructure technologies. The representative examples are various sensor technologies that can recognize surrounding objects and traffic environments, and artificial intelligence technologies that analyze information on behalf of people and control driving based on them. In addition, another essential technology is a vehicle network technology for implementing a connected car. A connected car that provides essential information for autonomous driving through a seamless network connection can be said to be one of the key elements for realizing autonomous driving. Currently, the connected car market is expanding rapidly, and it is expected that by 2020, 75% of vehicles launched will be equipped with hardware that supports Internet connectivity.

Meanwhile, 5G mobile communication (5G), the next-generation network technology, considers autonomous vehicles as the main application field, and in the field of IoT/IoE (Internet of Things/Internet of Everything), the vehicle is defined as one of the main things to be connected to the Internet. Doing. From this point of view, the vehicle network can be said to be a key field not only for autonomous vehicles but also for the next generation network.

10 shows an example of a V2X (Vehicle to everything) environment in the vehicle network. As shown in the figure, in the vehicle network, vehicles support various connections such as vehicles, vehicles and roadside devices, vehicles and network infrastructure, and vehicles and pedestrians, thereby providing various information necessary for vehicles in a timely manner.

As a technology for a vehicle network, a wireless access in vehicular environments (WAVE) based on IEEE standards is typical. In addition, mobile communication technology-based technologies have recently been proposed as part of the development of 5G mobile communication technology. However, looking at vehicle network technologies that have been mainly researched and developed until recently, it can be seen that most of them are based on single-hop communication between vehicles or between vehicles and network infrastructure.

The coverage of this single hop-based communication is limited to the area where the network infrastructure is built. Therefore, if a vehicle is located in an area where a network infrastructure is not constructed, it is inevitable to have a limitation in communication between vehicles or Internet connection if a special device such as satellite communication is not provided. Therefore, in order to be able to provide various services to be implemented through a connected car in the future, a multi-hop-based communication technology that can escape the limitations of single-hop communication is required. In a vehicle network based on multi-hop communication, the vehicle itself functions as a mobile router, so that multi-hop transmission between vehicles enables communication with a vehicle or network infrastructure located at a remote location even when a network infrastructure is absent locally.

The multi-hop-based vehicle network has a design requirement that is different from the multi-hop networking of the existing wired/wireless network in technical aspect due to the high dynamic characteristics of the vehicle. A typical example is that in a vehicle network, it may be difficult to maintain a stable network connection due to the vehicle's high speed and high mobility. This is a factor not considered in the existing network technology designed assuming stable end-to-end connection. On the contrary, the vehicle is advantageous in communication that it is not limited by power consumption, processing, and storage for networking because the vehicle is not greatly restricted by power supply and space provision. This characteristic is different from the Internet of Things (IoT) environment in which objects with limited capabilities, such as sensors, should be considered. Therefore, it can be said that there are various technical issues to be solved in order to support efficient multi-hop networking in a special environment of the vehicle network.

Among these technical issues, we examine the delay-tolerant vehicle networking technology that enables communication even in an environment where continuous connectivity between end nodes is not guaranteed due to the high dynamic characteristics of the vehicle. To this end, we analyze the technical background and key related technologies of delay-tolerant vehicle networking and summarize the main technologies that require future R&D based on this.

-Technology background

Vehicle networks have been reported to have a high dynamic characteristic in which frequent separation occurs unlike conventional wired/wireless networks, and also have a short time for communication between vehicles. VANET (Vehicular Ad hoc networks) is a technology proposed for multi-hop networking in this dynamic network topology, and is based on the existing mobile ad hoc networking technology, MANET (Mobile Ad hoc networks). The specific characteristics of the vehicle network considered by VANET are as follows.

* Predictable mobility of vehicles moving on the road.

* Fast network topology changes due to high speed vehicles.

* Variable topology according to time (eg traffic congestion) and location (eg city center, countryside).

* Scalability of multiple vehicles operating as network nodes.

* Network separation due to vehicle's limited communication range.

* Unlimited power consumption for data processing.

However, in the case of VANET, assuming that a communication path exists between end-to-end as in the existing communication method, there is a limit to support connectionlessness that may occur frequently in an actual vehicle network. In order to solve this problem, technologies for applying a previously designed Delay tolerant networking (DTN) technology to a vehicle network for a communication environment in which there is connectionlessness have been continuously proposed since mid-2000.

DTN was developed in 2007 in recognition of the problem that TCP/IP, an existing internetworking technology, does not work properly in an environment where very high latency, low data rate, disconnectability, and end-to-end connectivity may not exist. Was enacted as an IETF standard. It was first designed for interplanetary communication with poor connectivity, but it has been proposed to be applied to various fields with non-connectivity. According to a pre-planned schedule, sensor networks having intermittent connectivity, terrestrial radio networks with difficult end-to-end connectivity guarantees, and satellite communication with high delay and periodic connectivity are considered as fields that need to be applied.

In the case of TCP/IP, there is basically a continuous and bidirectional end-to-end communication path, and it is designed with the assumption of short round trip time, high transmission reliability, and symmetric data transmission/reception rate. Therefore, when it is applied to a network environment in which there is no connection, problems such as a decrease in TCP performance due to high delay, a decrease in performance at the network layer due to loss of packet fragmentation, and disconnection of routing due to physical connectionlessness between vehicles Have Therefore, in order to solve this problem, DTN newly designed a bundling layer between the transport layer and the application layer in the OSI (Open Systems Inter-connection) layer structure, and store and forward (SF) between bundle layers rather than end-to-end communication. It is designed to communicate in an environment where there is no connection through hop-by-hop communication. 11, the characteristics of the existing TCP/IP and DTN are briefly compared.

Vehicular delay tolerant network (VDTN) is a technology that applies this DTN technology to a vehicle network, and enables multi-hop communication between vehicles or between a vehicle and an infrastructure even in a dynamic network environment of the vehicle network. In other words, VDTN can be said to have evolved the existing VANET technology to efficiently support the special network environment of vehicle networks by introducing SCF (Store, Carry and Forward) technology, which is an evolved delivery technology from DTN.

VDTN can provide a variety of vehicle-based services such as:

* Road safety (collision prevention, inter-vehicle cooperation for road hazard notification, etc.).

* Optimize traffic conditions and road usage (prevent road congestion and monitor traffic conditions, etc.).

* Monitoring network for collecting sensor data (weather, pollution, road conditions, etc.).

* Commercial information (advertising, marketing information, travel information, parking information, etc.).

* Entertainment (Internet access, multimedia content sharing).

* Providing connectivity to remote areas such as the countryside or the Third World (file transfer, e-mail, cached web access, remote care).

* Emergency communication in disaster areas where existing network infrastructure is not available.

-Main technology

VDTN's main technologies such as structure, routing technology, next-generation networking technology, ICN (Information centric networking)-based vehicle network technology, and vehicle delivery network as an example of application in the wallpaper area will be described.

- rescue

As described above, the DTN network is composed of DTN nodes in which a new bundle layer is introduced between the transport layer and the application layer, as shown in FIG. 12.

At the end DTN node, the data of the application layer is converted into message units by the bundle layer, and then transmitted by hop-to-hop communication using the bundle protocol operating in the form of SF. Under the bundle layer, various network technologies including all OSI layers may exist. The application operates based on the bundle layer and is designed to include functions for communication quality management, such as minimizing exchange messages and restarting after disconnection during communication.

Such a DTN structure is a general structure, and if it is applied to a vehicle network as it is, there may be various inefficiencies. Therefore, various structures have been proposed for the VDTN, and among them, the VDTN structure as shown in FIG. 13 is considered the most influential. In this structure, the VDTN is a terminal node that provides connectivity to end users, a mobile node that delivers messages between end nodes, such as vehicles, and a fixed node located at the intersection to increase message transmission efficiency. It consists of a relay node.

As shown in FIG. 13, in the VDTN structure, unlike the existing DTN structure, the bundle layer is located between the network layer and the PHY/MAC. This allows multiple IP packets to be included in a single message and simplifies data processing and routing, reducing system complexity and achieving low cost and reduced energy consumption.

In addition, the VDTN structure is based on separation of a data plane (BAD: Bundle aggregation and de-aggregation) and a control plane (BSC: Bundle signaling control) as shown in FIG. 13. The BAD of the transmitting end collects IP packets to be transmitted in the unit of a bundle message and transmits them through a data plane, and the BAD of the receiving end performs a function of re-separating the received bundled message into IP packets. BSC is a signaling protocol for establishing a connection between VDTN nodes. It identifies the characteristics of the other node and exchanges control information for preparation for data transmission in the data plane. Separation of the data plane from the control plane can save resources and energy consumption in the data plane, such as storage capacity or bandwidth.

The difference between the existing DTN and VDTN is briefly summarized in FIG. 14.

The introduction of a bundle layer into an existing protocol stack, such as DTN or VDTN, inevitably increases the overhead due to duplicate processing. In an environment where IP-based applications are the main current situation, such overhead may be inefficient. In order to solve this overhead problem, a structure supporting DTN and IP in a hybrid form has also been proposed. 15 shows a hybrid structure based on a gateway called'IP-cum-DTN'.

In the gateway-based hybrid structure as shown in FIG. 15, the IP-based application operates in the form of dynamically selecting the DTN area if there is an end-to-end route and data is transmitted through the IP area. . As a result, the existing IP-based application can be used as it is on the host, thereby improving delivery efficiency in an environment where the IP-based application is predominant.

-Routing protocol

Since the vehicle network has a short contact time between vehicles and a high dynamic topology, the routing protocol technology to properly support this environment can be said to be a core technical issue of the VDTN along with the VDTN structure. The routing protocol for the VDTN is basically based on the DTN routing protocols, and has been developed in a way to apply it to the vehicle network environment.

The DTN routing protocol can be roughly divided into a single-copy method and a multiple-copy method. The single copy method maintains only a single copy of a bundle message when forwarding between network nodes. This method can save network resources such as storage devices and bandwidth and energy, but low transmission rates and large delays can be a problem. Direct delivery method that carries the bundle until the sending node meets the receiving node, First contact method that delivers the bundle to the first node it meets, and geographic delivery that reduces the geographical distance to the destination based on the location information of the node. ) Routing method is a typical example. On the other hand, the multiple copy method is a method of copying a bundle message multiple times when contacting between nodes. Since each copy of the bundled message is delivered independently, it has the advantage of high probability of delivery due to multi-path. In addition, delivery delay can be minimized by using an optimal delivery path through multiple paths. On the other hand, there is a great inefficiency in terms of network resource consumption. A typical example of multiple copies is the Epidemic method, which manages a list of bundle messages that a node needs to deliver and exchanges all unlisted bundle messages when contacting between nodes, limiting the number of copies made per bundle to control flooding. Spray and Wait, and MaxPro, which manages priority by scheduling bundles to be delivered in case of node to node and bundles to be discarded in case of overflow.

Among the various protocols as described above, a routing protocol worth paying attention to particularly in terms of a vehicle network is a geographic routing protocol. Geo-routing is a routing method in which the decision on forwarding is based on the location of the receiver by default. When a node with data to be delivered meets another node, the data is transferred to the node where the other node is closer to or more likely to reach the final receiver's location. Is the Greedy routing method. Since the geographic routing protocol performs routing according to the location information of each node, the network is a stateless method that does not maintain state information. Therefore, it is simpler and more efficient than other methods. In other words, it is not necessary to configure a network topology that is difficult to configure in a dynamic vehicle network or has a large overhead, and single copy routing can be used with low consumption of network resources. In addition, it is also an advantage of geographical routing that the location information of each node is easy to use since most vehicles have already built an environment in which most of the vehicles can basically use GPS information or a vehicle route, such as a navigation system. Fig. 16 briefly summarizes the characteristics of the major delay-tolerant geographic routing protocols proposed so far.

-Information-centric networking (ICN)

Recently, studies have been conducted to overcome the limitations of host-based TCP/IP technology that assumes stable end-to-end connectivity in a vehicle network environment based on a new network technology, information centric networking (ICN). ICN is basically a new communication method to communicate based on the information itself, not the host where the information is located. ICN has a feature that it can structurally support delay-sensitive communication by including in-network caching, which can store data for a considerable amount of time, as a basic element.

When using ICN for multi-hop communication in a vehicle network, it can have advantages in terms of application, mobility, and security compared to the existing TCP/IP technology. First, in terms of application, if the application nature of the vehicle network basically deals with content such as road surface conditions or traffic conditions, or if it is an information-centric nature independent of the information producer, it fits well with the basic concept of ICN. ICN also simplifies mobility management by allowing basic vehicle functions, Anycast and caching within the network, to bring the information the vehicle needs from the most convenient node, such as the nearest repository, based on the name of the information. . In addition, since ICN structurally supports the SCF function, it is possible to efficiently respond to a disconnected state due to mobility. In terms of security, ICN can provide improved security by applying security to the content itself, unlike channel security in host-based TCP/IP.

17 shows an example of a structure in which ICN is applied in a WAVE-based vehicle network. As shown in the figure, ICN can be used as a technology to replace the existing TCP/IP at the network and transport layer.

-Vehicle transmission network

As the world rapidly changes to an Internet-based information society, access to the Internet is regarded as one of the basic human rights set by the United Nations. However, it is reported that the world's population with access to the Internet is still 40% of the total population, and the remaining 60% of the population is living in a difficult environment where Internet access is difficult. Google's LOON project and Facebook's internet. The org project is a representative example of R&D that is being done to support Internet access in this poor network environment. The delay-tolerant vehicle network is a technology that can be useful in such environments.

The vehicle transmission network can provide a low-cost Internet connection to the wallpaper area as a method of delay-sensitive communication in which the vehicle directly transmits data in a poor network environment in which a network infrastructure is not secured. DakNet and KioskNet, which developed it, are representative technologies. 18 is a conceptual diagram of DakNet in which services are actually provided in rural areas of India and Cambodia.

In the figure, Kiosk located in each village does not have a connection to the Internet, so the bus and DTN protocol act as a gateway for the connection between Kiosk and neighboring towns that have an Internet connection. The bus acting as a mobile access point receives a request from the village user for Internet access through Kiosk, delivers it to a town with Internet access, receives a response, moves it back to the village area, and delivers it to the Kiosk. Through this vehicle delivery network, it is possible to build a low-cost infrastructure for providing various Internet-based services such as email, web browsing, telemedicine, grain price information, and tax payment.

The vehicle transport network uses a PRoPHET routing protocol that performs stochastic routing without randomly moving network nodes due to the nature of the traffic infrastructure moving along the road. The PRoPHET routing protocol operates in the form of delivering a copy based on the delivery predictability of the contact node with the destination node.

-Research Trend

At the present time, the concept of the connected car concept is in its infancy, and the research on delay-tolerant vehicle networks is still in its infancy.

-IRTF/IETF

In early 2000, a group called Delay Tolerant Networking Research Group (DTNRG), which is responsible for DTN-related research, was created under the Internet Research Task Force (IRTF), an organization that mainly performs all phases of Internet standards. After coming to work, the work in 2016 was finally completed. Through the DTNRG activities, standardization of DTN-based technologies such as DTN structure and bundle protocol was achieved, but the work was completed without proceeding to the vehicle network part.

As for the vehicle network, a group of ITS technologies, which had been working in the form of Birds of a Feather (BoF), recently established a new working group (WG) within the Internet Engineering Task Force (IETF). Founded at the end of 2016 under the name of IPWAVE (IP Wireless Access in Vehicular Environments), this working group applies IPv6 to connect to the Internet based on IEEE 802.11 Outside the Context of a Basic Service Set (OCB), a representative vehicle network technology. Discussion of the problems to be solved is currently underway, and currently, work on problem analysis when IPv6 is applied to a vehicle network is mainly performed. However, the IPWAVE working group mainly focuses on IPv6-based vehicle network technology, so the discussion on delay-sensitive communication discussed in this paper has not been addressed yet.

Another notable group related to delay-tolerant communication is ICTF of IRTF. As described above, ICN basically has a delay-tolerant communication characteristic. ICNRG worked to develop technical scenarios for ICN and develop various scenarios to actually apply ICN, a new network protocol. Through this work, the vehicle network was proposed as one of the most promising fields that can have advantages through the application of ICN.

-Future Internet base

Since the beginning of 2000, research has been actively conducted worldwide in the name of the future Internet to overcome the limitations of current TCP/IP based Internet technologies. Representative examples of such research are the NDN and MobilityFirst projects conducted with the support of the American Science Foundation. After the basic network structure design, the two projects are actively developing application fields to apply new network technology as the next step, and the vehicle network is considered as one of the promising applications.

Since the recent network environment is rapidly changing in the direction of increasing mobility of communication nodes, both future Internet structures are designed to support delay-sensitive communication. In the case of NDN, ICN's networking function is included to provide delay-sensitive communication functions. In the NDN project, V-NDN technology, which applied NDN to an automotive network environment, was developed to prove the superiority of performance in a vehicle network environment and distribute it as open source. MobilityFirst basically proposed an integrated structure based on MobilityFirst for vehicle networks as a network structure designed to support delay-sensitive communication in a wireless-oriented environment. MobilityFirst structurally supports delay-tolerant communication through GNRS (Global name resolution system), a local storage and late binding, which is a mapping system between identifiers and addresses, and can efficiently support large-scale vehicle network environments through simulation. Proved.

Delay-tolerant vehicle networking technology is an essential technology for the realization of a connected car because it can extend the communication coverage to areas where the network infrastructure does not reach, but it is still in the early stages of research in the world.

In addition to the delay-tolerant vehicle networking technology, Connected Car has many technical issues to be solved in order to realize the future vision. Efficient interworking between heterogeneous networks in a vehicle network environment in which various wired and wireless access technologies exist, integrated identification system for vehicles and contents, application of new concept networks such as information-centric networks, efficient networking using vehicle devices such as navigation systems, and vehicle-based Emergency communication systems are a prime example. In particular, as the security problems of vehicles due to connected cars have emerged seriously recently, it can be said that the development of technology for this is an urgent problem to be solved.

The following describes a delay/split-tolerant network.

The Internet protocol applied to the terrestrial network operates in a network environment where message transmission time is guaranteed based on end-to-end connectivity. However, in a space communication environment, it is impossible to apply an Internet protocol such as Transmission Control Protocol (TCP), which requires end-to-end connectivity due to a large transmission delay and a communication link disconnection due to the movement or propagation characteristics of the planet. Also, in order to overcome the space communication environment in which high transmission errors occur, high-level error correction technology must be additionally applied.

Delay- and Disruption-Tolerant Network (DTN) is a concept proposed for interworking between heterogeneous networks with different transmission delay characteristics, and for this purpose, connectivity of networks composed of different transport protocols on the transport layer. It has a Bundle Protocol (BP) that guarantees, and through this, it can support inter-node communication even in environments where end-to-end connectivity is not guaranteed. The delay/split-allowed network uses the store-and-forward message transmission method. When the connection between nodes is lost, the message is stored in the node. When a connection is created, the message is transmitted to the next node according to the applied routing method. In addition, it is possible to adjust the message size so that the message can be stably transmitted according to the communication link and the limited transmission time generated intermittently through message fragmentation.

Therefore, the delay/split-tolerant network is suitable for a space communication environment in which a large transmission delay occurs due to intermittent communication link disconnection due to these advantages, and is also delayed in the Consultative Committee for Space Data Systems (CCSDS), an international standardization agency for space communication. Standardization of fragmentation-tolerant network protocols is in progress.

When the delayed/divided network is applied to space communication, low earth orbit (LEO) satellites, geostationary orbit (GEO) satellites, lunar orbiters, etc. can be used as relay nodes. It can solve the problems faced by transmission delay and high transmission error in the communication between the Moon and Earth.

The message transmission rate in the delayed/split-tolerant network is affected by the space communication environment under consideration, especially the moving model of dynamically moving nodes. Therefore, by dividing the message in consideration of the movement of the nodes and analyzing the relationship between the time-to-live (TTL) and the buffer space (TTL) according to the routing technology, efficient resource utilization in the delayed/divided network is possible. It is possible, and it is possible to guarantee stable message transmission to the destination node.

The delayed/disrupted network is considered as a solution to the problems raised in the space communication environment, but there have not been many studies for performance analysis and performance improvement.

As a related research, the message transmission performance according to the routing technique and congestion control technology is analyzed by considering a model in which two satellites exist at a fixed location for communication between a ground station (GS) and a Mars probe. Did. However, it is necessary to further analyze the relationship between the message space and the buffer space, which considers the movement of the planets and satellites, and has a significant effect on message transmission performance.

We analyze the problems that will occur when delivering a large amount of messages in the communication between the earth base station and the moon probe, and present a space communication model to which the delay/disruption allowance network is applied to solve the problems. Considers the 3-hop relay space communication environment that transmits messages from the Earth base station to the moon probe through the Earth satellite (low orbit satellite or geostationary satellite), the Moon orbit, and in particular, the rotation of the Earth, the orbit of the Earth satellite and the Moon orbit , The time at which the Earth Base controls the Earth satellite, and the time at which the communication link between the Earth satellite and the Moon orbit, the Moon orbiter and the Moon probe is formed, is reflected and modeled by reflecting the actual space communication environment. The proposed space communication model was implemented as an ONE (Opportunistic Network Environment) simulator, and the optimal message life, buffer space, and message transmission rate according to message segmentation were analyzed to ensure the reliability of the message transmitted from the earth base station to the moon probe. Suggestions for efficient resource utilization.

-Delay/split network

☞ Limits of Earth base station-moon probe communication

Currently, the message capacity to send is not large, so it is possible to send a message directly from the earth base station to the moon probe. Considering the low transmission speed due to the transmission power of the limited earth base station and the high transmission delay according to the distance between the earth and the moon (360,000 km), the size of the message transmitted from the earth base station to the moon probe at a time is limited. In addition, in the current transmission method, when a transmission error occurs in the transmitted message, the earth base station retransmits the transmission error message to the moon probe.

However, considering the current situation in which the amount of messages to be transmitted from the earth base station to the moon probe gradually increases, the current message retransmission method does not effectively solve the problem of transmission error in transmitting large messages. Considering the waste of resources due to message retransmission at the terrestrial base station and high transmission delay due to message retransmission, it is necessary to apply a new communication model for efficient transmission of large messages.

☞ Network with delay/disruption

As introduced in the introduction, delay/split-tolerant networks have a bundled protocol for connectivity between heterogeneous networks with different transmission delay characteristics. This makes it possible to apply appropriate transmission protocols between interplanetary, interplanetary-satellite, and satellites, and enables communication between nodes even if end-to-end connectivity is not guaranteed, thereby enabling message transmission. In addition, the problem of the current system that occurs when a large message is transmitted can be solved by guaranteeing stable message transmission between nodes through message division, and ultimately by guaranteeing message transmission to a destination node (moon probe).

FIG. 19 shows a 3-hop space communication environment using earth satellites (low orbiting satellites or geostationary orbiting satellites) and moon orbit lines as relay nodes to which a delay/disruption allowing network is applied from the earth base station to the moon probe. Considering the limited message transmission speed of the earth base station and the long message transmission time between the earth and the moon, it is assumed that the message transmitted from the earth base station is received only by the earth satellite. The inter-satellite (Earth Satellite-Moon Orbital) communication link is determined by the movement of the satellite and the relative position of the satellite, and if the inter-satellite communication link is not formed, by the store-and-forward message transmission method, the earth satellite is the earth base station. After storing the message received from the buffer space and orbiting the earth, the corresponding message is transmitted when the moon orbit and the communication link are formed.

Therefore, the performance of the delay/split-tolerant network applied to space communication is determined by the available communication time between nodes, the size and life of transmission messages, the node buffer space, the routing technique, and the earth satellites, and each characteristic is described in the following subsections. . In this paper, when transmitting a large message (assuming 10MB message in this paper) from the earth base station to the moon probe, considering the space communication environment scenario using two earth satellites (low orbit satellite and geostationary satellite), Discuss how to allocate resources to maximize.

-Earth Base Station-Earth Satellite Communication

In the communication between the earth base station and the earth satellite, the time at which the earth base station controls the earth satellite varies according to the altitude of the satellite and the position of the earth base station. In the case of a low-orbit satellite orbiting at an altitude of 630 km, orbiting the earth takes about 90 minutes (540 seconds), orbiting the earth about 16 times a day. At this time, considering the terrestrial base station that controls the low-orbit satellite at a specific location, on average, it forms a communication link with the low-orbit satellite four times a day, and each control time lasts for about 15 minutes (900 seconds).

Based on this, in this paper, the contact period and contact duration of the ground base station and the low-orbit satellite were modeled as 21600 seconds and 900 seconds, and the ground base station was connected to the low-orbit satellite for 24 hours (86400 seconds) per day. The time to form the communication link is presented in FIG. 20. 'Contact On' means that the communication link between the earth base station and the earth satellite has been established, and indicates that the communication link is created at 0,21600, 43200, 64800 seconds, and 900 seconds is maintained.

On the other hand, the geostationary satellite (altitude 35,678 km) orbits the earth once a day, but orbits at the same speed as the earth's rotation speed, so it is possible to always control the geostationary satellite from the base station on the ground. Therefore, it is modeled that a geostationary satellite always forms a communication link with the earth base station.

-Message characteristics

When a large base station transmits a large message to an earth satellite, the performance of message transmission varies depending on the type of earth satellite utilized. In a space communication environment scenario using low-orbit satellites, considering the limited base station transmission speed and satellite control time (15 minutes), it is impossible to transmit large-capacity messages from the earth base station to low-orbit satellites at once. On the other hand, in a space communication environment scenario using a geostationary satellite, the geostationary satellite can always be controlled by the ground base station, so that a large message can be transmitted from the earth base station to the geostationary satellite at a time.

In the case of inter-satellite communication, since the message transmission speed supported by the earth satellite is very low, and the time during which the inter-satellite communication link is formed is limited due to the movement of the satellite and the relative position thereof, a large-scale message is also transmitted from the moon to the moon. It is impossible to transmit by line at once.

Therefore, when a large-scale message is transmitted from the earth base station to the moon probe, it is impossible in a 3-hop relay space communication environment to transmit messages between nodes at once, so the bundle protocol of the delay/split-tolerant network supports this. Introducing the concept of message segmentation, we present a method for delivering large-scale messages from earth base stations to the moon probe.

-Dictionary message splitting

The International Internet Standards Organization (IETF) document RFC 5050 defines the specifications for the bundled protocols essential to delay/split-tolerant networks. The bundled protocol is an overlay network concept and supports store-and-forward message transmission. In addition, it supports the concept of message division so that messages are reliably transmitted to the destination node, so that each divided message is independently routed and transmitted to the destination node, and finally the original message is restored at the destination node.

Message segmentation methods include proactive message fragmentation and proactive message fragmentation.

To apply the pre-message segmentation method to the space communication environment, a fragmentation factor must be defined. The division coefficient 1/n means that one message is divided into n messages of the same size. If the pre-division is not performed, it is assumed that the first message (10 MB) transmitted from the ground base station is divided into four messages of the same size (2.5 MB) in consideration of controlling the earth satellite No. 4 on the ground base station. Table 2 below shows the message size divided according to the division factor when message division is applied.

Additionally, in a space communication environment scenario using a geostationary satellite, the geostationary satellite can be controlled at a ground base station throughout the day. However, for fair transmission performance comparison and analysis of scenarios using low orbit satellites and geostationary satellites, the message sizes shown in Table 2 are assumed in scenarios using geostationary satellites.

-Message life and buffer space

Message lifetime and buffer space are closely related to the successful transmission of a message to the destination node. In a limited buffer space, if a message with a very large message lifetime cannot be delivered to the next destination node, the message is not discarded and continues to occupy the buffer space. If the message cannot be continuously delivered, the newly created message is not delivered due to insufficient buffer space of the node and is discarded. On the other hand, if the message life is very short, a problem occurs in that the message is destroyed before reaching the destination node.

The low-orbit satellite takes 90 minutes to orbit the Earth. If the message lifespan is less than 90 minutes, messages stored on low-orbit satellites are destroyed before orbiting the Earth, and new links are formed, preventing them from being sent to the Moon. Therefore, the following message life time was set in consideration of the movement of the low-orbit satellite and the moon orbit, and the minimum message life that can guarantee the reliability of message transmission is derived through analysis of simulation results.

22 shows this.

-Routing technique

Epidemic, Spray and wait, and PRoPHET are dynamic routing techniques that can be applied in a delay/split-tolerant network. Epidemic routing is a flooding-based routing method that sends a copy of a message to all nodes in contact, so that the message is delivered to the final destination node. The spray and wait method operates on the same principle as the epidemic routing method, but it can efficiently manage the buffer space of the node by limiting the number of copied messages. The PRoPHET routing method is an estimation-based routing method, which increases the message transmission rate, but has the disadvantage of requiring additional overhead.

In a 3-hop relay space communication environment, the association of message lifetime and buffer space rather than routing technique has a major effect on message transmission rate. So the simplest

Epidemic routing technique is applied to analyze message transmission performance.

-Comparison of low orbit and geostationary satellite scenarios

The characteristics of the space communication environment using the low orbit satellite and the geostationary orbit satellite can be summarized as shown in FIG. 23.

-Moon communication simulation

-ONE simulator

The ONE (Oppertunistic Netwrok Environment) simulator is suitable for constructing a delayed/disrupted network environment and evaluating message transmission performance by providing various mobility models and routing techniques of nodes. In this paper, the performance of message transmission in space communication environment scenarios was analyzed using the ONE simulator.

-ONE simulator: mobility model of nodes

ONE simulator has the advantage of implementing various movement models of nodes. The movement model of nodes provided by the ONE simulator can be summarized into the following three categories. 1) Random movement model, 2) Map-based movement model, 3) Human movement-based movement model. The space communication environment was constructed considering the map-based movement model among the above three movement models.

In order to implement a movement model in which the earth satellite and the moon orbiter revolve around the earth and the moon in the ONE simulator, a map-based movement model and a map route movement are applied to the earth satellite and the moon orbiter. The orbits of the Earth's satellites and the moon's orbit are made using the commercial program OpenJUMP in the GIS (Graphic Information System).

24 shows a GUI (Graphic User Interface) showing the space communication environment implemented by the ONE simulator. The location of the Earth and Moon is fixed, and each represents the Earth base station and the Moon probe. The low-orbit satellite and the moon-orbit line orbit along a circular orbit, and the existence of a communication link and the communication time are determined according to the relative positions between the satellites. 24 shows the time when the communication link of the low orbit satellite and the moon orbit line is formed, and the earth base station -. Low Orbit Satellite -. Lunar Orbit-Shows the 3-hop relay communication environment of the lunar probe.

The time to control the earth satellite from the earth base station according to the rotation of the earth and the revolution of the earth satellite can be confirmed in Table 1, and the connection time and the connection cycle accordingly are reflected in the ONE simulator.

-Simulator variable setting

In order to build a realistic space environment by utilizing the ONE simulator, simulation variables as shown in FIG. 25 are set.

The space communication environment of 24 hours (86400 seconds) was considered, and the transmission speeds of the ground base station, the earth satellite, and the moon orbit were assumed to be 4 kB/s, 0.5 kB/s, and 1 kB/s. Considering the earth's radius (6,387 km), the altitude of low orbit satellites and geostationary orbit satellites, the moving speed of satellites in each orbit was calculated, and the pre-message segmentation shown in Table 2 was used to evaluate the message transmission rate according to the segmentation The message size and message generation cycle were set by applying the coefficients. Various message life values were set to reflect that the low orbit satellite took 90 minutes to orbit the earth, and the buffer space was set to 0.5MB-10MB considering the minimum value (0.25MB) among the divided message sizes.

-Performance analysis

As a performance indicator for ensuring the reliability of the message transmitted from the earth base station to the moon probe, the delivery ratio may be considered. The message transmission rate is defined as follows.

Message rate=

If the message transmission rate is less than 1, it indicates that there are some messages generated by the Earth that could not be delivered to the lunar probe. Therefore, by analyzing the message life, the buffer space and the message partitioning coefficient of which the message transmission rate is 1, an optimal resource utilization method can be derived.

For fair performance analysis of scenarios using low-orbit satellites and geostationary-satellite satellites, 1 revolution in FIGS. 26 to 31 represents the orbital time (90 minutes) of the low-orbit satellites.

26 and 27 show the effect of message lifetime, message division coefficient, and buffer space on the message transmission rate in a space communication environment scenario considering a low orbit satellite.

26 shows the message transmission rate when the buffer space of the low orbit satellite and the moon orbit is 5 MB. When the message division coefficient is 1/10, it indicates a higher message transmission rate than the remaining coefficient values. Even if a communication link between satellites is established, a message having a size of 0.25 MB or more means that a low orbit satellite cannot be transmitted to the moon orbit line. This is due to the short inter-satellite communication time due to the revolution of the satellite and the low transmission speed of the low-orbit satellite (0.5kB/s). In addition, when message division is not applied, it can be confirmed that the message transmission rate is 0. This means that messages larger than 2.5 MB cannot be transmitted in inter-satellite communication, and it can be seen that message division is necessary to transmit a message to the moon probe. In the case of message life, if the message is not destroyed while the low-orbit satellite orbits the earth 8 times (message life = 720 minutes), it can be seen that the message transfer rate is 1, and if the message life is less than 720 minutes, the moon probe There is a message that could not be sent to. This means that the duration of the inter-satellite communication link is insufficient, so that messages stored in the low-orbit satellite's buffer space are destroyed before being sent to the moon probe. Therefore, in order to ensure the reliability of the message by applying the store-and-forward message delivery method and the message division method when transmitting a large message of 10MB from the earth base station to the moon probe, sufficient message life time must be guaranteed.

27 shows a message transmission rate when the buffer space of a low-orbit satellite and a moon orbit line is 0.5 MB. When the message division coefficient is 1/4, it can be confirmed that the message is not transmitted to the moon probe, which is smaller than the size of the divided message (0.625 MB) and the buffer space of the low-orbit satellite is smaller (ie, 0.5 MB <0.625 MB), the Earth. This is because the message received from the base station cannot be stored by the low-orbit satellite. In addition, compared to the message transmission rate when the satellite buffer space is 5MB (FIG. 26), it can be confirmed that when the buffer space is 0.5MB, the message transmitted to the moon probe is small. This is because the buffer space of the low-orbit satellite is insufficient, and new messages transmitted from the earth base station are discarded without being stored in the low-orbit satellite.

28 shows that in a satellite communication environment considering a low-orbit satellite, a 0.25 MB segmented message (message division coefficient 1/10) is transmitted from the earth base station, and if a buffer space of 2.5 MB or more is secured to the satellite, all messages are sent to the moon probe. You can confirm that it is delivered.

29 to 31 show a change in the message transmission rate according to the message lifetime, message division coefficient, and buffer space in a communication environment using geostationary satellites. Since the earth base station can always control the geostationary satellite, it can be confirmed that the existence of the communication link between the satellites and the communication time have an important effect on the message transmission rate. When the message with sufficient message life (over 720 minutes) is divided and transmitted (size 0.25MB), and enough buffer space (over 2.5MB) is secured in the geostationary satellite, the earth base station utilizes the geostationary satellite to the moon probe. Reliability of the delivered message can be guaranteed.

Finally, comparing the results of FIGS. 26 to 28 with FIGS. 29 to 31, right

It can be confirmed that the transmission rate of the message transmitted to the moon probe varies depending on the type of earth satellite used in the main communication environment (low orbiting satellite or geostationary satellite). In particular, when the message lifetime is set to be smaller than 360 minutes (TTL = 4 revolutions), or if the buffer space of the satellite is not sufficiently secured, it can be seen that the message transmission rate is high in the space communication environment using the low-orbit satellite. This indicates that the use of low-orbit satellites, in which the inter-satellite communication link is frequently formed, is advantageous for transmitting a large-capacity message to the moon probe than the geostationary-satellite satellite in which the inter-satellite communication link is limited.

In conclusion, the concept that is used for delay/disruption tolerant networks is applied to the space communication environment where end-to-end connectivity is not guaranteed and long transmission time is required. The real space environment was implemented using the ONE simulator, and resources were efficiently utilized, and at the same time, the relationship between optimal message life, buffer space, and message segmentation was derived to ensure the reliability of the message delivered to the moon probe. The analyzed results can be applied to real systems, and can be expanded to research on system models and technologies to overcome the limited inter-satellite transmission speed.

To further organize the network structure for reliable information transmission in a fire scene according to an embodiment of the present invention, a DTN (Delay and Disruption Tolerant Network) designed for interplanetary communication with poor connectivity is used instead of TCP/IP. By using and applying the multi-copy routing protocol, it is possible to stably and reliably transmit information between firefighters and between the firefighters and the command and control center, while at the same time stably searching for the location of the requestor.

Incidentally, a single copy routing protocol may save network resources, but may cause low transmission rates and large delays. On the other hand, the multi-copy routing protocol is a method of copying and transferring data multiple times when contacting between nodes, and has a high probability of transmission due to multiple paths.

As described above, in the present description, specific matters such as specific components and the like have been described by limited embodiments and drawings, but they are provided only to help a more comprehensive understanding of the present invention, and the present invention is limited to the above embodiments No, those skilled in the art to which the present invention pertains can make various modifications and variations from these descriptions.

Therefore, the spirit of the present invention is limited to the described embodiments, and should not be determined, and it will be said that not only the claims described below, but all those with equivalent or equivalent modifications to the claims fall within the scope of the spirit of the present invention.

10: mobile communication terminal 100: firefighter portable terminal
110: artificial intelligence hardware 111: communication module between terminals
112: PDR communication module 113: command control communication module
114: signal processing communication module 115: application processor
200: Firefighter's location tracking safety boots 210: Inertial sensors
300: command control computer

Claims (1)

Artificial intelligence hardware for signal processing in the terminal, which detects wireless communication information of the mobile communication terminal 10 carried by a firefighter, and carried by a request assistant at a fire site, displays location information of the mobile communication terminal 10, 110) is mounted, the artificial intelligence hardware 110 includes a communication module 111, a command and control communication module 113 and a signal processing processor 114 between terminals, and simultaneously transmits and receives data to and from the signal processing processor 114. A firefighter's portable terminal 100 including an application processor 115 that provides a multi-signal pattern collection function and a 3D precision positioning platform interworking function based on the firefighter's portable terminal 100;
The firefighter's position tracking safety shoes worn by the firefighter and equipped with an inertial sensor 210 provide a self-positioning function of the firefighter based on the inertial sensor 210 and have a shortest return path guidance display function in an emergency. (200); And
The location information of the firefighter's portable terminal 100 is received, and the location tracking software of the firefighter using the signal of the inertial sensor 210 of the firefighter's location tracking safety boots 200 and the search for the request of the firefighter's request or the safety of the firefighter's safety The firefighter's route search software for returning is mounted, and the firefighter's position tracking software tracks the indoor location using the walking characteristics of the firefighter's walking force based on the inertial sensor 210, and uses the firefighter's route finding software. It includes a command and control computer 300 that provides an exploration route for the performance of the firefighter's mission through,
Providing a single inertial sensor-based walking navigation system through the inertial sensor 210 to minimize constraints due to sensor characteristics, to consider firefighter's motion based on learning, and to estimate the position of a position using information on movement,
Provides a location monitoring system for firefighters, monitors the location of firefighters and their location, and provides directions or directions for progress through a route planning algorithm.
Network structure for reliable information transmission at the fire site, characterized in that the firefighter can visualize three types of information: terminal UI, helmet and air respirator.

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