KR20250044561A - Method and system for Multi-channel TDMA slot resource integrated management, coordination and sharing for maritime VHF band data exchange system - Google Patents

Abstract

The present invention relates to a method and system for integrated management, coordination, and sharing of multi-channel TDMA slot resources for a maritime VHF band data exchange system. The multi-channel TDMA slot resource integrated management, coordination, and sharing system according to one embodiment of the present invention ensures harmonious balance of the data link by minimizing waste of resources between different radio stations participating in a data link and sharing transmission resources according to priorities among an automatic identification system (AIS), an application specific message (ASM), and a very short-wave data exchange (VDE), thereby reducing the influence of radio collisions and interference within the data link.

Description

Method and system for multi-channel TDMA slot resource integrated management, coordination and sharing for maritime VHF band data exchange system

The present invention relates to a method and system for integrated management, coordination, and sharing of multi-channel TDMA slot resources for a maritime VHF band data exchange system.

The Automatic Identification System (AIS), a maritime VHF band digital radio communication system, was first introduced to mandatory ships in accordance with the International Convention for the Safety of Life at Sea in July 2002. However, as application technologies, equipment, and services that share AIS channel resources have emerged to meet various demands related to digital information transmission at sea, the number of available channel resources has gradually decreased. Accordingly, the International Maritime Organization (IMO) decided to introduce a Very High Frequency Data Exchange System (VDES), which integrates the Automatic Identification System (AIS), Application Specific Messages (ASMs), and Very High Frequency Data Exchange (VDE), in order to maintain the management function of the existing AIS for maritime traffic safety and to provide various types of maritime digital information services. The ultra-shortwave data exchange system will maintain the basic functions of the existing AIS related to maritime traffic safety, and will function as a means of exchanging information between ships and providing various maritime services required between ships and shores. It is also expected to be widely utilized as a global maritime safety and service information transmission system through information linkage between ships and satellites, and shore/operating stations and satellite earth stations.

AIS, ASM, and VDE integrated in VDES must be able to perform receiving operations independently. For transmitting operations, each component participating in the data link is synchronized based on Coordinated Universal Time (UTC), and information is transmitted by sharing a time slot with 26.666… milliseconds as a unit time according to the time division multiple access (TDMA) method, and priority use of slot resources is given according to the information exchange target, type, and size, and this is done through selective application of standardized specifications such as channel frequency, bandwidth size, modulation/demodulation method, and code rate.

The highest priority is given to AIS related to maritime traffic control and safe navigation of ships, and cargo information collection in coastal countries, followed by ASM used for special purposes and regional/international applications, and then terrestrial VDEs and satellite VDEs providing various maritime services are given priority for communications in that order. This means that when more than one communication system using adjacent frequency channels transmits signals, in order not to interfere with the reception of signals with low field strength on adjacent frequency channels, a communication system with a lower priority can take a method of avoiding the same time slot that a system with a higher priority is using/will use for its communication activities so as not to interfere with the communication activities of a higher priority system.

However, in these cases, the number of time slots that can be used by low-priority communication systems, especially terrestrial VDEs and satellite VDEs, is extremely limited, significantly reducing channel operation efficiency. Therefore, a close resource sharing cooperation system is required among data link participating components to efficiently utilize limited resources.

Embodiments of the present invention provide a method and system for integrated management, coordination, and sharing of multi-channel TDMA slot resources for a maritime VHF band data exchange system, which ensures channel operation efficiency of a communication system with low communication priority without impeding the reception of signals with low field strength in adjacent frequency channels when one or more communication systems (AIS, ASM, VDE) using adjacent frequency channels transmit signals between ship-to-ship, ship-to-shore, and ship-to-satellite within a coast station control area.

Embodiments of the present invention provide a method and system for integrated management, adjustment, and sharing of multi-channel TDMA slot resources for a maritime VHF band data exchange system, which ensures a harmonious balance of data links by minimizing waste of resources between different radio stations participating in a data link while reducing the influence of radio collisions and interference within the data link, and sharing transmission resources according to priorities among an automatic identification system (AIS), an application specific message (ASM), and very high frequency data exchange (VDE) constituting a single integrated VDES system.

However, the problem to be solved by the present invention is not limited thereto, and may be expanded in various ways in environments that do not deviate from the spirit and scope of the present invention.

According to one embodiment of the present invention, a multi-channel TDMA slot resource integrated management system for a maritime VHF band data exchange system may be provided, comprising: a message distribution device for distributing messages between a coastal station and a resource sharing device; and a resource sharing device for receiving, from the coastal station, dynamic and static information messages generated based on messages received at the coastal station and signal information messages about slot resources used for transmission, and generating a resource information sharing map matching a resource information map generated at the coastal station using the received dynamic and static information messages and the signal information messages, wherein the resource sharing device receives a resource request message from a ship station within a communication coverage area of the coastal station through the message distribution device, derives available resources from the generated resource information sharing map using the received resource request message, and allocates the derived available resources to the ship station through the message distribution device.

Dynamic and static information messages generated based on messages received from the above coastal station and signal information messages on slot resources used for transmission can be generated as a resource information sharing map in the form of a table by synthesizing the identification code of the coastal station or the ship station, separation distance, channel information, slot number used in the corresponding channel, and slot plan to be used in the corresponding channel.

The above resource sharing device can generate a resource information sharing map that matches the AIS (Automatic Identification System) resource information map, the ASM (Application Specific Message) resource information map, and the VDE (VHF Data Exchange) resource information map of the coastal station by using the received dynamic and static information messages and signal information messages.

The above resource sharing device can select a group of allocatable slot candidates through channel-by-channel slot status analysis from the generated resource information sharing map, and compare the selected group of slot candidates with a resource information sharing map generated based on information received from an adjacent coastal station having a communication coverage area overlapping with the communication coverage area of the coastal station to derive available resources.

The above resource sharing device can derive available resource candidates according to communication priority based on a search condition that a slot state having the same offset constituting a TDMA (Time Division Multiple Access) channel is a free slot from the generated resource information sharing map.

The above resource sharing device may omit searching for a slot state of the same offset constituting a TDMA channel in the ASM resource information map and the VDE resource information map if the slot state of the same offset constituting a TDMA channel in the AIS resource information map with a high communication priority is not an empty slot.

The above resource sharing device can derive, as an available resource candidate, a selectable logical channel from the earliest point in time starting from a TDMA frame in which a selectable logical channel exists following the current TDMA frame in which the resource request message is received.

The above logical channel is defined as a function of a set of consecutive slots within the same TDMA channel in the horizontal direction, and the physical channel is defined by a maritime mobile service band frequency and bandwidth, and each physical channel is associated with one VDE slot map and can be mapped to one or more logical channels consisting of a Bulletin Board Signaling Channel (BBSC), an Announcement Signaling Channel (ASC), a Random Access Channel (RAC), a Data Channel (DC), and a Data Signaling Channel (DSCH).

The disclosed technology may have the following effects. However, this does not mean that a specific embodiment must include all or only the following effects, and thus the scope of the disclosed technology should not be construed as being limited thereby.

Embodiments of the present invention can ensure channel operation efficiency of a communication system with a low communication priority without impeding reception of signals with low field strength on adjacent frequency channels when one or more communication systems (AIS, ASM, VDE) using adjacent frequency channels transmit signals between ship-to-ship, ship-to-shore, and ship-to-satellite within a coast station control area.

Embodiments of the present invention provide a multi-channel TDMA slot resource integration management, coordination, and sharing technique and system for a maritime VHF band data exchange system, which can share transmission resources according to priorities among an automatic identification system (AIS), an application specific message (ASM), and a very short wave data exchange (VDE) constituting a single integrated VDES system, and minimize resource waste between different radio stations participating in a data link while also reducing the influence of radio collisions and interference within the data link, thereby ensuring a harmonious balance of the data link.

FIG. 1 is a diagram illustrating a linked configuration of a coastal station communicating directly with a ship station according to an embodiment of the present invention, a message distribution device that is linked to multiple coastal stations and transmits designated message packets, and a resource sharing device that maintains and manages a coastal station resource information sharing map of all regions.
FIG. 2 is a diagram illustrating a multi-channel TDMA slot resource integration management, coordination, and sharing system for a maritime VHF band data exchange system according to an embodiment of the present invention.
FIG. 3 is a drawing showing a synchronization procedure and method of a resource information sharing map between a coastal station and a resource sharing device for a maritime VHF band data exchange system according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating a procedure and method for requesting resources and allocating available resources between a ship station, a coast station, and a resource sharing device for a maritime VHF band data exchange system according to an embodiment of the present invention.
FIG. 5 is a diagram illustrating a method for deriving a selectable logical channel by comparing resource information sharing maps after the current frame between VDES communication systems of adjacent coastal stations whose communication areas overlap according to an embodiment of the present invention.
FIGS. 6 to 8 are diagrams illustrating an example of a method for analyzing available resources using free slots as keywords according to priorities in a VDES communication system according to an embodiment of the present invention.
FIG. 9 is a diagram showing a table showing map generation parameters for available resource analysis of ASM and VDE according to an embodiment of the present invention.
Figures 10 to 12 are drawings showing unique communication technology characteristics of VDE(S) according to an embodiment of the present invention.
FIG. 13 is a configuration diagram of a resource sharing device for a maritime VHF band data exchange system according to one embodiment of the present invention.

The present invention can be modified in various ways and has various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it can be understood that all modifications, equivalents, or substitutes included in the technical spirit and technical scope of the present invention are included. In describing the present invention, if it is determined that a specific description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The terms first, second, etc. may be used to describe various components, but the components are not limited by the terms. The terms are used only to distinguish one component from another.

The terms used in the present invention are only used to describe specific embodiments and are not intended to limit the present invention. The terms used in the present invention were selected from widely used general terms as much as possible while considering the functions of the present invention, but this may vary depending on the intention of a technician working in the relevant field, precedents, or the emergence of new technologies. In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in this case, the meanings thereof will be described in detail in the description of the relevant invention. Therefore, the terms used in the present invention should be defined based on the meanings of the terms and the overall contents of the present invention, rather than simply the names of the terms.

Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present invention, it should be understood that terms such as "comprise" or "have" are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

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

FIG. 1 is a diagram illustrating a linked configuration of a coastal station communicating directly with a ship station according to an embodiment of the present invention, a message distribution device that is linked to multiple coastal stations and transmits designated message packets, and a resource sharing device that maintains and manages a coastal station resource information sharing map of all regions.

As illustrated in FIG. 1, a multi-channel TDMA slot resource integrated management, coordination, and sharing system (100) according to one embodiment of the present invention includes a ship station (110), a coast station (120), a message distribution device (130), and a resource sharing device (140). However, not all of the illustrated components are essential components. The multi-channel TDMA slot resource integrated management, coordination, and sharing system (100) may be implemented with more components than the illustrated components, or may be implemented with fewer components.

A coast station (120) has a coast station control area. A ship station (110) operating within one or more overlapping coast station control areas can transmit an automatic position reporting message (AIS) or an application specific message (ASM). In addition, a ship station (110) within the control service area range within the jurisdictional sea area set by the coast station (120) can transmit a data exchange message (VDE) through a resource request and allocation for information transmission to the coast station.

The coastal station (120) creates a resource information map for ship stations (110) and adjacent coastal stations within the coastal station control area, and shares information for creating a resource information sharing map with a resource sharing device (140) through a message distribution device (130).

A message distribution device (130) is connected to a plurality of coastal stations (120) and transmits messages sent or received by the coastal stations (120) to a resource sharing device (140) or transmits messages received from the resource sharing device (140) to the coastal stations (120).

The resource sharing device (140) uses messages received from coastal stations (120) in all regions through the message distribution device (130) to create a resource information sharing map for all coastal stations that matches the resource information map that the coastal station (120) creates on its own, and continuously maintains and manages the same.

FIG. 2 is a diagram illustrating a multi-channel TDMA slot resource integration management, coordination, and sharing system for a maritime VHF band data exchange system according to an embodiment of the present invention.

The area within a radius of 120 NM from a coast station is considered a coast station control area. A radio station (ship station transponder) (110) of a ship operating within one or more overlapping coast station control areas can transmit an Automatic Information System (AIS) message using a SOTDMA access system according to the ship's speed and course, and can transmit an Application Specific Message (ASM) using an ITDMA or MITDMA access system depending on the availability of local services.

Additionally, a ship station transponder (110) within the control service area range within the jurisdictional waters set by the coastal station can transmit a data exchange message (VDE) to the coastal station through a resource request and allocation for information transmission.

A message transmitted from the ship station transponder (110) can be simultaneously received by the coast station A transponder (121) and the adjacent coast station B transponder (122) having overlapping coast station control areas. At this time, the coast station transponders (121, 122) can know the type of communication system used for transmission and channel information through independently operating channel receivers, and can measure the reception field strength and signal-to-noise ratio for each received message. In addition, the coast station transponders (121, 122) can identify the unique number of the ship through the maritime mobile service identification (MMSI), location information, and communication state information included in the AIS, ASM message transmitted by the ship station transponder (110). The coast station transponder (121, 122) can know the slot number (0 to 2,249) used by the ship station transponder (110) for the transmission and the slot plan (slot timeout, 7 to 0) to be additionally used for message transmission.

Coastal station transponders (121, 122) synthesize the identification code, separation distance, channel information, slot number used in the channel, and slot plan to be used in the channel of the corresponding ship station to create a resource information map in the form of a table. The target of this resource information map is not only the ship station transponder (110), but also the coast station transponders (121, 122), so that a resource information map can be created for an adjacent coast station B transponder (122) within the communication range of the coast station A transponder (121). The resource information map is created in a minimum of 4 frames (1 frame is 1 minute) and a maximum of 7 frames, and the relevant information is updated upon each reception.

When a coast station transponder (121, 122) receives a message transmitted from a ship station transponder (110) operating within a coast station control area, the coast station transponder may configure a VDM (AIS)/ADM (ASM)/EDM (VDE) message (sentence) of the NMEA protocol, and if the coast station transponder is the message transmitter, configure a VDO (AIS)/ADO (ASM)/EDO (VDE) message (sentence) and output it through a presentation interface configured as a serial communication port or an Ethernet communication port. At this time, the coast station transponder (121, 122) generates a related VHF data link signal information message (VSI sentence) together with a position information message received from another radio station and outputs them as a pair. This VHF data link signal information message contains the unique identification code of the coast station that generated the VSI message (sentence), a multi-sentence message sequence identifier, the time of message reception in UTC hours, minutes, seconds and fractions of a second, the number of the first slot used to transmit the message, and values for the received signal strength indicator (RSSI) and signal-to-noise ratio (SNR).

A pair of VDM/ADM/EDM or VDO/ADO/EDO messages (sentences) and VSI messages (sentences) output from a coastal station transponder (121, 122) are input to a message distribution device (130). The message distribution device (130) is linked to multiple coastal stations within a region, and can convert messages sent or received by coastal stations into message packets in a format that can be processed by an external system for the purpose of maritime traffic control, search and rescue, marine accident investigation, etc., and transmit them. In addition, the message distribution device (130) converts information messages, service messages, etc. that an external system intends to broadcast or individually transmit through the coastal station into message packets in a format that can be processed by the coastal station transponder (121, 122) and transmits them to the coastal station. The message distribution device (130) can be configured with equipment that processes load distribution according to message packets with different processing methods in one or more multiplexing configurations, and has a function of determining whether a message transmitted by a ship station transponder (110) located in an overlapping coast station control area is received repeatedly and filtering it.

A pair of VDM/ADM/EDM or VDO/ADO/EDO messages (sentences) and VSI messages (sentences) input to the message distribution device (130) are transmitted to the resource sharing device (140) for analysis of available resource status and allocatable resources of coastal stations within all regions.

The resource sharing device (140) uses information such as the type and channel information of the communication system in the coastal station's transmission or reception message and VHF data link signal information message transmitted to coastal stations in all regions, the maritime mobile service identification code (MMSI), location information, the slot number (0 to 2,249) used for the transmission, and the slot plan (slot timeout, 7 to 0) to be additionally used for message transmission, to create a resource information sharing map in the same form as the resource information map recorded by the coastal station itself, and can continuously maintain and manage the same.

Meanwhile, we will explain the procedures and methods for processing and responding to VDE resource requests from ships.

The ship station transponder (110) shall be able to identify whether the ship station is within the coast station control area by monitoring the coast station bulletin board message using Link ID 11 on channels 1024 and 2024 at all times through an independently operated channel receiver. If the ship station transponder (110) is determined to be within the coast station control area, it shall adjust the configuration of the physical channel and resource information map according to the contents of the coast station bulletin board message.

When a ship station belonging to a coast station control area wants to transmit information to other ships or the coast within the communication coverage using VHF data exchange technology, the ship station transponder (110) must request resources necessary for transmission to the coast (however, transmission may be made without resource allocation only in the case of short messages using a single time slot (26.666… milliseconds)). This is to prevent data link congestion that may occur due to the abuse of messages using multiple transmission slots, i.e., to prevent transmission of high-priority AIS and ASM messages from being hindered by VDE messages.

A resource request is made by transmitting a resource request message packet including a unique identification code (generator) of a ship station requesting resources and a unique identification code (destination) of a coast station receiving resources through a random access channel specified in a coast station bulletin board message. The coast station transponder (121) that receives the resource request message, if the destination matches its own unique identification code, configures the resource request message received from the ship into a message packet promised between the coast station and the message distribution device (130) and transmits it to the resource sharing device (140) through the message distribution device (130).

The resource sharing device (140) that receives the resource request of the ship station transponder (110) selects a group of allocatable slot candidates by analyzing the slot status of each channel of each communication system from the resource information map of the coast station A transponder (121) that received and transmitted the resource request. Then, the resource sharing device (140) compares and analyzes the selection result with the resource information map of the adjacent coast station having an overlapping communication coverage area within the communication coverage area, and determines and distributes allocated resources that do not affect or can minimize the effect on AIS and ASM transmission and VDE transmission of the adjacent coast station.

FIG. 3 is a drawing showing a synchronization procedure and method of a resource information sharing map between a coastal station and a resource sharing device for a maritime VHF band data exchange system according to an embodiment of the present invention.

In steps S101 and S102, the coast station A transponder (121) receives a message from the ship station transponder (110), and the adjacent coast station B transponder (122) also receives a message from the same ship station transponder (110).

In steps S103 and S104, the coast station A transponder (121) generates dynamic and static information messages and signal information messages for slot resources used for transmission based on the received messages, and updates and sets the resource information map of coast station A using the dynamic and static information messages. The adjacent coast station B transponder (122) generates dynamic and static information messages and signal information messages for slot resources used for transmission based on the received messages, and updates and sets the resource information map of coast station B using the dynamic and static information messages. Here, each coast station generates dynamic and static information messages and signal information messages in text format in ASCII code using the binary message received from the ship station. At this time, the signal information message may be referred to as the same message as the VDL signal information message (VSI, VDL Signal Information Message). The VDL signal information message indicates a text message including additional signal information for the VDL message (such as the TDMA slot number used when the VDL (VHF Data Link) message is transmitted to the airship) on a serial or Ethernet communication network.

In steps S105 and S106, the message distribution device (130) receives dynamic and static information messages generated from a coast station A transponder (121) and VDL signaling information messages about slot resources used for transmission. The message distribution device (130) receives dynamic and static information messages generated from an adjacent coast station B transponder (122) and VDL signaling information messages about slot resources used for transmission.

In step S107, the message distribution device (130) transmits dynamic and static information messages and VDL signal information messages received from each coastal station to the resource sharing device (140).

In step S108, the resource sharing device (140) generates a resource information sharing map that matches the resource information map of the coastal station using the transmission/reception messages, VDL signal information messages, etc. received through the message distribution device (130).

FIG. 4 is a diagram illustrating a procedure and method for requesting resources and allocating available resources between a ship station and a resource sharing device for a maritime VHF band data exchange system according to an embodiment of the present invention.

In step S201, the coast station A transponder (121) receives a resource request message from the ship station transponder (110).

In step S202, the message distribution device (130) receives a resource request message from the coast station A transponder (121).

In step S203, the message distribution device (130) transmits a resource request message received from the coastal station A transponder (121) to the resource sharing device (140).

In step S204, the resource sharing device (140) derives available resources from the resource information sharing map according to the resource request message received through the message distribution device (130).

In step S205, the resource sharing device (140) generates a resource allocation message according to the derived available resources and transmits it to the message distribution device (130).

In steps S206 and S207, the message distribution device (130) transmits a resource request message to the coast station A transponder (121) and transmits a resource request message to the coast station B transponder (122).

In steps S208 and S209, the coastal station A transponder (121) updates and sets the resource information map of coastal station A according to the resource request message received from the message distribution device (130), and the adjacent coastal station B transponder (122) updates and sets the resource information map of coastal station B according to the resource request message received from the message distribution device (130).

In step S210, the coast station A transponder (121) transmits the received resource request message to the ship station transponder (110) to allocate resources to the ship station.

FIG. 5 is a diagram illustrating a method for deriving a selectable logical channel by comparing resource information sharing maps after the current frame between VDES communication systems of adjacent coastal stations whose communication areas overlap according to an embodiment of the present invention.

As illustrated in FIG. 5, according to an embodiment of the present invention, through service data linkage (511) of coast station A, coast station A AIS reporting and service schedule, coast station A ASM reporting and service schedule, coast station A VDE upper/lower leg service schedule, and through coast station A, Presentation Interface data linkage (512), VDO/VDM/VSI, ADO/ADM/VSI, EDO/EDM/VSI are used to create a ship AIS resource map, a coast AIS resource map, a ship ASM resource map, a coast ASM resource map, a ship VDE resource map, and a coast VDE resource map. In addition, according to an embodiment of the present invention, coast station A VDES resource map creation (513) is performed using coast station A AIS resource map, coast station A ASM resource map, and coast station A VDE resource map.

Meanwhile, according to an embodiment of the present invention, through the service data linkage (521) of coastal station B, coastal station B AIS reporting and service schedule, coastal station B ASM reporting and service schedule, coastal station B VDE upper/lower leg service schedule, and through the coastal station B, Presentation Interface data linkage (522), VDO/VDM/VSI, ADO/ADM/VSI, EDO/EDM/VSI are used to create a ship AIS resource map, a coastal AIS resource map, a ship ASM resource map, a coastal ASM resource map, a ship VDE resource map, and a coastal VDE resource map. And according to an embodiment of the present invention, coastal station B VDES resource map creation (523) is performed using the coastal station B AIS resource map, the coastal station B ASM resource map, and the coastal station B VDE resource map.

The resource sharing device (140) according to an embodiment of the present invention can identify an AIS empty slot group, an ASM empty slot group, and a VDE selectable logical channel group by using the coastal station A VDES resource map and the coastal station B VDES resource map. The resource sharing device (140) according to an embodiment of the present invention can derive a selectable logical channel by comparing the resource information sharing maps after the current frame between the VDES communication systems of adjacent coastal stations whose communication areas overlap according to an embodiment of the present invention.

FIGS. 6 to 8 are diagrams illustrating an example of a method for analyzing available resources using free slots as keywords according to priorities in a VDES communication system according to an embodiment of the present invention.

We will explain a method for analyzing available resources through initialization of the VDES resource information map and real-time resource status information update.

The coast station has resource information maps (610, 620, 630, 640) for each of the AIS, ASM, and VDE-TER communication systems, respectively. The resource information maps (610, 620, 630, 640) are generated by using messages received through data link monitoring for the AIS channel and ASM channel for 1 frame (1 minute) from the time the system first starts operating, to generate the AIS resource information map (610) and the ASM resource information map (620) for ship stations within the radio reception range, and during this period, the coast station adds resource utilization plans for coast station report messages, control/management, and (application) service messages set by itself to the AIS resource information map (610) and the ASM resource information map (620) to complete the initial configuration.

In addition, a VDE resource information map (630, 640) is created that reflects a pre-planned coastal station VDE-TER Bulletin Board message or a resource utilization plan for maritime service data transmission provided from a service center, and allocable resource information derived by analyzing TDMA time slot resources requested by ship stations within the controlled service area range within the jurisdictional sea area set by the coastal station is reflected in the VDE-TER resource information map to update it.

Adjacent coastal stations have mutually exclusive service areas, and the timing of coastal station message transmission, such as coastal station reporting or control/management, (application) services, bulletin boards, and maritime service data, must be set and registered by adjusting the service type and service cycle, etc. according to the plan established in advance by the competent authority so that they do not conflict with each other. In addition, an independent resource information map can be configured between the upper leg and lower leg depending on the coastal station's communication channel operation mode.

The resource sharing device (140) generates a resource information sharing map that matches the resource information maps generated by each of a plurality of coastal stations within the jurisdiction. The resource sharing device (140) continuously updates the resource information sharing map for each frame, compares the resource information sharing maps between communication systems of adjacent coastal stations with overlapping communication areas, and analyzes/derives available resource candidates, i.e., selectable logical channels, according to the communication priority, based on a search condition that a slot state having the same offset that configures a TDMA channel is a free slot according to the communication system priority.

Since the slot state can have one of the following states: free slot, internal allocation, external allocation, available, and unavailable, the search speed can be increased by deriving available resource candidates according to communication priority from slot states of the same offset that constitute the TDMA channel, rather than deriving available resource candidates from each slot state.

As shown in FIGS. 6 to 8, the AIS resource information map (610) includes in-use slots (611) and available slots (612), which are a set of horizontally continuous slots. The ASM resource information map (620) includes in-use slots (621) and available slots (622), which are a set of horizontally continuous slots. The in-use slots may include internally allocated slots, externally allocated slots, and unavailable slots. The available slots may include available and empty slots.

The VDE selectable upper leg logical channel (630) includes a slot (631) corresponding to the same position as the slot (611) in use in the AIS resource information map (610), a slot (632) corresponding to the same position as the slot (621) in use in the ASM resource information map (620), an available slot (633) in the VDE selectable upper leg logical channel which is a set of horizontally continuous slots, and an available slot (643) in the VDE selectable lower leg logical channel which is a set of horizontally continuous slots.

In other words, since even if only one slot of the slots of the same offset constituting the TDMA channel in FIGS. 6 to 8 is used, it cannot become an available resource candidate, so the resource sharing device (140) can determine whether or not there is an empty slot based on the same offset. If the slot state of the same offset constituting the TDMA channel in the AIS resource information map with high communication priority is not an empty slot, the resource sharing device (140) can omit searching for the slot state of the same offset constituting the TDMA channel in the ASM resource information map (620) or the VDE resource information map (630, 640) as a selectable logical channel. Through this, the resource sharing device (140) can quickly perform a search operation for a selectable logical channel.

When both lower leg and upper leg transmissions of a ship station are allowed in a coast station service area, the number of available resources in the upper leg (160 MHz band) adjacent to the AIS and ASM frequency channels may be zero or fewer than that in the lower leg. However, the number of available resources is relatively larger in the lower leg (150 MHz band) where the frequency gap with the AIS and ASM frequency channels is large. The available slots (643) as available resources in the VDE selectable lower leg logical channel may be zero or fewer than that in the VDE selectable upper leg logical channel (633). As the channel bandwidth decreases, the amount of data transmitted decreases, but the number of available resources increases. In other words, a large number of users can utilize communication resources with a small capacity.

Here, selection of resources required for allocation can be made from a TDMA frame in which a selectable logical channel exists following the current TDMA frame in which the resource request is received, and the selectable logical channel with the earliest point in time is allocated to the first received resource request.

FIG. 9 is a diagram showing a table showing map generation parameters for available resource analysis of ASM and VDE according to an embodiment of the present invention.

The map generation parameters for ASM/VDE available resource analysis illustrated in Fig. 9 are described.

The parameters for creating a map for analyzing available resources include the frame number (frameNum), slot number (slotNum), remaining slot count (slotTimeout), channel division (channelDistn), and slot state (slotState).

Frame numbers are assigned in 1-minute increments, for a total of 1,440 frames per day, and are reset to 0 after 1 day.

The slot number refers to the slot number used for transmission, and is specified in units of 26.666… milliseconds, with a total of 2,250 slots per minute, and is initialized to 0 after 1 minute.

The number of slots remaining indicates how many more frames the current slot will be used for in the future, and is used as an important indicator for establishing slot usage plans.

The channel division has a total of 17 channels divided by frequency and bandwidth, and the VDE channels (4 to 17) follow the simplex/duplex mode selection of the coast station bulletin board message and the 25kHz/50kHz/100kHz bandwidth mode selection.

The slot status of ASM and VDE is divided into free slot, internally allocated slot, and externally allocated slot, and includes available slot and unavailable slot status only for AIS slot status. However, the available slot and unavailable slot status of AIS are not used in ASM and VDE available resource analysis.

Meanwhile, let's explain the AIS slot status.

Free (F): The slot is not used within the reception range of the own radio station. An externally allocated slot that has not been used for the previous three frames is also a Free slot. This slot can be considered as a candidate slot for use by the own station. 3-minute Missed Report (T): Assigned to another ship underway that has not received a signal for more than 3 minutes.

Available: The slot is allocated externally by a station and is a possible candidate for slot reuse. Far Allocation (D): Assigned by the station furthest away.

Not Available: The slot is externally allocated by the station and is not a candidate for slot reuse. Internally allocated (I): The slot is allocated by the station and is available for transmission. Externally allocated (E): The slot is allocated for transmission by another ship station within 120 NM of the ship. Coastal allocated (B): The slot is allocated by a coastal station within 120 NM of the ship. (X): Not available.

Meanwhile, we will explain the AIS reuse slot selection rules.

Rule 1: Free on selected channels and available on other channels

Rule 2: Available on selected channels and not used on other channels (Free)

Rule 3: Available on both channels

Rule 4: Free on selected channels and unavailable on other channels

Rule 5: Available on selected channels and unavailable on other channels

(1) Available - Mobile station (SOTDMA or ITDMA) or Coastal station reserved (FATDMA or Message 4) slots beyond 120 NM

(2) Unavailable - Coastal station reservation (FATDMA or Message 4) slot within 120 NM or mobile station reporting slot without location information

Let's explain the ASM, VDE slot status.

Free: Not available or allocated.

allocated: if externally allocated by an ASM or VDE radio station

unavailable

1. When internally allocated for transmission from its own radio station.

2. If the same slot as the AIS channel is allocated by the AIS radio station.

1) SOTDMA slot timeout = 0

2) Slots allocated to FATDMA radio stations within 120 NM

3. If internally assigned to its own radio station for address messages

4. If assigned for receiving its own radio station VDE

5. If assigned to receive VDE-TER or VDE-SAT bulletin boards.

Meanwhile, we will explain the candidate slot selection rules for ASM RATMDA transmission.

0. There must be at least a set of 8 candidate slots to choose from.

1. Candidate slots are initially selected from free slots in all VDES channels.

2. Unused on all AIS and ASM channels, unused or allocated on VDE channels.

3. Unused on any AIS channel, unused or allocated on another ASM channel or VDE channel.

4. Unused on one AIS channel, available on another AIS channel, unused or allocated on an ASM channel or VDE channel.

5. Available on all AIS channels, unused or allocated on other ASM channels or VDE channels.

Meanwhile, we will explain the candidate slot selection rules for VDE RAC transmission.

0. There must be at least a set of 8 candidate slots to choose from.

1. Candidate slots are initially selected from free slots in all VDES channels.

2. Unused on all AIS and VDE channels, assigned to one ASM channel and unused on other channels.

3. Unused on all AIS and VDE channels, allocated on all ASM channels.

4. Available on one AIS channel and one other AIS channel, unused or allocated on all ASM channels, unused on VDE channels.

5. Available on all AIS channels, unused or allocated on all ASM channels, unused on VDE channels.

A logical channel (LC) can be marked as unused if no LC assignment has been received for three consecutive TDMA frames. Whenever a logical channel (LC) is used for its own radio transmission or reception, the logical channel (LC) must be marked as internally allocated for the current TDMA frame and the next three TDMA frames.

Figures 10 to 12 are drawings showing unique communication technology characteristics of VDE(S) according to an embodiment of the present invention.

The unique communication technology characteristics of VDE(S) will be explained with reference to FIGS. 10 to 12.

VDE(S) uses the same multiple access method as the TDMA technology of the conventional AIS with 2,250 time slots per minute (26.666… milliseconds). This means that VDE(S) is not a separate communication technology from AIS, but rather a communication technology that encompasses AIS and is a broader concept.

However, it is very different from the conventional AIS in terms of the TDMA frame structure and the way it uses the physical/logical channels required for message transmission and reception, and although it has some similarities in frame structure and channel use with mobile communication technologies that use TDMA technology such as GSM and LTE, it is differentiated in the uplink/downlink communication method.

First, as shown in Fig. 10, the frame structure of AIS does not have a concept of a subframe smaller than a single communication frame having 2,250 time slots per minute. The frame is composed of only a sequential arrangement of slots in two physical channels.

On the other hand, as shown in Fig. 11, VDE has six consecutive slots forming one hex slot. The time interval of a hex slot is 160 milliseconds, and the slot time of each slot is 26.666… milliseconds. The hex slot must increase every six slots.

A TDMA channel is all slots with the same offset in a hex slot. Every sixth slot is part of the same TDMA channel. A total of six TDMA channels are defined, based on the order of the hex slots (0 to 5).

A TDMA channel is divided into TDMA frames. The basic time interval of a TDMA frame is defined by 15 hex slots within the TDMA channel. TDMA frames are numbered from 0 to 24. There is a function for setting the TDMA frame length by the coast station, and the frame length can be increased or decreased by selectively varying the number of hex slots.

A TDMA slot defines a slot number within a TDMA frame. When the TDMA frame length is 15 slots, TDMA slots are numbered cyclically from 0 to 14.

In addition, the frame structure of VDE(S) introduces the concept of logical channels that can be seen in mobile communications. These are BBSC(Bulletin Board Signaling Channel), ASC(Announcement Signaling Channel), RAC(Random Access Channel), DC(Data Channel), and DSCH(Data Signaling CHannel). This logical channel defines the function of a set of consecutive slots in a TDMA channel, and can be repeated in every TDMA frame.

As illustrated in Figure 12, physical channels are defined by frequency and bandwidth. VDE(S) has four physical channels, each with a 25 kHz bandwidth in the upper band (160 MHz band) and the lower band (150 MHz band), and two adjacent channels can be bundled to use a 50 kHz bandwidth, or four channels in the upper and lower bands can be bundled to use a 100 kHz bandwidth.

Each physical channel is associated with one VDE slot map, which maps to one or more logical channels consisting of Bulletin Board Signaling Channel (BBSC), Announcement Signaling Channel (ASC), Random Access Channel (RAC), Data Channel (DC), and Data Signaling Channel (DSCH). Each physical channel and logical channel can be used for uplink (ship-to-shore) and downlink (shore-to-ship) communications as needed, without separating frequencies or dividing time.

Mobile communication technologies such as GSM and LTE are very similar to VDE(S) in that they consist of large and small sub-frames (TDMA frame, Multi frame, Super frame, Hyper frame, etc.) that make up the entire frame and that the concept of logical channels is applied.

However, VDE(S) is differentiated from mobile communications such as GSM and LTE in that it is based on two-way device-to-device (D2D) communication between ships and shore on a single frequency (simplex mode) without using frequency division duplex (FDD) in which uplink and downlink channels are separated, or time division duplex (TDD) in which uplink operation occurs for a certain period of time and downlink operation occurs for a certain period of time.

Meanwhile, when explaining the VDE-TER link layer and the TDMA system, a TDMA channel is defined as six TDMA channels numbered from 0 to 5. A hex slot consists of six consecutive slot numbers assigned in the order of the TDMA channel number. For example, 26.7ms x 6 is approximately 160ms. A TDMA slot has slot numbers from 0' to '14' assigned to each group of Hexslots constituting a TDMA frame. A TDMA frame consists of a total of 25 frames when composed of Default 15 (Changeable to 2, 3, 5, 6, 7, 10) Hex slots. For example, Hexslot (6) x TDMA slot (15) x Total number of frames (25) = 2,250.

The link layer can be defined as follows:

Logical Channel (LC) defines the function for a set of consecutive slots within the same TDMA channel (horizontal direction). For example, BBSC, RAC, ASC, DC, DSCH, RC. Physical Channel (PC) is defined by maritime mobile service band frequency and bandwidth. For example, 4 Lower Leg channels (1024, 1084, 1025, 1085) and 4 Upper Leg channels (2024, 2084, 2025, 2085). VDE slot map Each physical channel is associated with one VDE slot map and mapped to one or more logical channels consisting of Bulletin Board Signaling Channel (BBSC), Announcement Signaling Channel (ASC), Random Access Channel (RAC), Data Channel (DC), and Data Signaling Channel (DSCH). Bulletin Board defines the physical channels together with the VDE slot map for the control station service area, and is transmitted by the control station. Short Data Message is a data transmission protocol used to transmit payload in only one slot. It does not require resource request/transfer and resource allocation messages and is transmitted on the random access channel (RAC). Data session is a data transmission protocol used to transmit data packet payload. Multi-session data transmission is multiple data sessions linked together to enable transmission of large data packet payloads. Data fragments are data that can be divided into multiple fragments during a data session and transmitted in separate slots. When transmitting data fragments over a single TDMA channel, 14 data fragments can be transmitted (assuming they do not interfere with AIS transmissions).

Let's explain the Control Station Service Area.

The information is transmitted as Bulletin Board messages via logical channel '0'. For example, Northeast latitude/longitude, Southwest latitude/longitude. The scope and target are only applicable to ships within the control station service area. While the ship station is within the control station service area, all data session transmissions between ships must be made through the control station. However, ships outside the control station service area (ships that have been confirmed to be within the communication range by AIS reception) can communicate directly.

The constraints require that the control stations have mutually exclusive service areas. The timing of the Bulletin Board broadcast on logical channel '0' needs to be coordinated so that it is shared appropriately between the control stations. In addition, if a VDE ship station detects that it is not within the control station service area, it should communicate using the default Bulletin Board.

In terms of Resource Management, the method of transmitting information between ships and shore is to establish a session on a logical channel that the control station reserves for a given time for a specific ship upon request. Short Data Messages generated on ships are transmitted on the Random Access Channel (RAC) without resource allocation. Network load management methods include introducing time distribution for resource requests; modifying the maximum allowable number of Short Data Messages generated on ships; or allowing only high priority traffic. Binary byte storage order (Endianness) is the target and method of Endianness, and uses the same Endianness as AIS in relation to the message structure. When generating a message, it must be grouped into 8-bit bytes from top to bottom in the table associated with each message. Multi-byte words are filled with the most significant byte in the message first.

Describes the data structures. Common conditions are that VDE packet transmissions must always fall within one slot (26.7ms). The number of bits transmitted per packet must be fixed according to the link ID used. A packet must consist of one or more VDE messages, zero padding, and a CRC. The padding is defined as a separate message. The CRC is always located at the end of the packet.

FIG. 13 is a configuration diagram of a resource sharing device for a maritime VHF band data exchange system according to one embodiment of the present invention.

As illustrated in FIG. 13, a resource sharing device (140) for a maritime VHF band data exchange system according to one embodiment of the present invention includes a communication module (210), a memory (220), and a processor (230). However, not all of the illustrated components are essential components. The resource sharing device may be implemented with more components than the illustrated components, or may be implemented with fewer components.

Below, the specific configuration and operation of each component of the resource sharing device (140) of Fig. 13 are described.

The communication module (210) can communicate with the message distribution device (130).

The memory (220) stores one or more programs related to a method for integrating, coordinating, and sharing multi-channel TDMA slot resources for a maritime VHF band data exchange system.

The processor (230) executes one or more programs stored in the memory (220). The processor (230) receives, from a coastal station, dynamic and static information messages generated based on messages received from the coastal station and signal information messages about slot resources used for transmission, generates a resource information sharing map matching a resource information map generated from the coastal station using the received dynamic and static information messages and signal information messages, receives a resource request message from a ship station within a communication coverage area of the coastal station through the coastal station, derives available resources from the generated resource information sharing map using the received resource request message, and allocates the derived available resources to the ship station.

According to embodiments, dynamic and static information messages generated based on messages received from a coastal station and signal information messages on slot resources used for transmission can be generated as a resource information sharing map in the form of a table by synthesizing identification codes of coastal stations or ship stations, separation distances, channel information, slot numbers used in the corresponding channel, and slot plans to be used in the corresponding channel.

According to embodiments, the processor (230) may use the received dynamic and static information messages and signal information messages to generate a resource information sharing map that matches the coast station's Automatic Identification System (AIS) resource information map, Application Specific Message (ASM) resource information map, and VHF Data Exchange (VDE) resource information map.

According to embodiments, the processor (230) selects a group of allocatable slot candidates through channel-by-channel slot status analysis from the generated resource information sharing map, and compares the selected group of slot candidates with a resource information sharing map generated based on information received from an adjacent coastal station having a communication coverage area overlapping with the communication coverage area of the coastal station to derive available resources.

According to embodiments, the processor (230) can derive available resource candidates according to communication priority by using a search condition that a slot state having the same offset constituting a TDMA (Time Division Multiple Access) channel is a free slot from the generated resource information sharing map.

According to embodiments, the processor (230) may omit searching for a slot state of the same offset constituting a TDMA channel in the ASM resource information map and the VDE resource information map if the slot state of the same offset constituting a TDMA channel in the AIS resource information map with a high communication priority is not an empty slot.

According to embodiments, the processor (230) may derive the earliest selectable logical channel from the TDMA frame in which the resource request message is received, as an available resource candidate, in which there is a selectable logical channel following the current TDMA frame.

According to embodiments, a logical channel is defined as a function of a set of consecutive slots within a same TDMA channel in a horizontal direction, a physical channel is defined by a maritime mobile service band frequency and bandwidth, and each physical channel is associated with one VDE slot map and can be mapped to one or more logical channels composed of a Bulletin Board Signaling Channel (BBSC), an Announcement Signaling Channel (ASC), a Random Access Channel (RAC), a Data Channel (DC), and a Data Signaling Channel (DSCH).

Meanwhile, according to one embodiment of the present invention, the various embodiments described above may be implemented as software including instructions stored in a machine-readable storage medium that can be read by a machine (e.g., a computer). The device may include an electronic device (e.g., an electronic device (A)) according to the disclosed embodiments, which is a device that calls instructions stored from the storage medium and can operate according to the called instructions. When an instruction is executed by a processor, the processor may directly or under the control of the processor perform a function corresponding to the instruction by using other components. The instruction may include code generated or executed by a compiler or an interpreter. The machine-readable storage medium may be provided in the form of a non-transitory storage medium. Here, 'non-transitory' means that the storage medium does not include a signal and is tangible, and does not distinguish between data being stored semi-permanently or temporarily in the storage medium.

In addition, according to one embodiment of the present invention, the method according to the various embodiments described above may be provided as included in a computer program product. The computer program product may be traded between sellers and buyers as a commodity. The computer program product may be distributed in the form of a storage medium that can be read by a machine (e.g., compact disc read only memory (CD-ROM)) or online through an application store (e.g., Play StoreTM). In the case of online distribution, at least a part of the computer program product may be temporarily stored or temporarily generated in a storage medium such as a memory of a manufacturer's server, an application store's server, or a relay server.

In addition, according to one embodiment of the present invention, the various embodiments described above can be implemented in a recording medium that can be read by a computer or a similar device using software, hardware, or a combination thereof. In some cases, the embodiments described in this specification can be implemented by the processor itself. According to a software implementation, embodiments such as the procedures and functions described in this specification can be implemented by separate software modules. Each of the software modules can perform one or more functions and operations described in this specification.

Meanwhile, computer instructions for performing processing operations of a device according to the various embodiments described above may be stored in a non-transitory computer-readable medium. The computer instructions stored in the non-transitory computer-readable medium, when executed by a processor of a specific device, cause the specific device to perform processing operations in the device according to the various embodiments described above. The non-transitory computer-readable medium refers to a medium that stores data semi-permanently and can be read by a device, rather than a medium that stores data for a short period of time, such as a register, a cache, or a memory. Specific examples of the non-transitory computer-readable medium may include a CD, a DVD, a hard disk, a Blu-ray disk, a USB, a memory card, or a ROM.

In addition, each of the components (e.g., modules or programs) according to the various embodiments described above may be composed of a single or multiple entities, and some of the corresponding sub-components described above may be omitted, or other sub-components may be further included in various embodiments. Alternatively or additionally, some of the components (e.g., modules or programs) may be integrated into a single entity, which may perform the same or similar functions performed by each of the corresponding components prior to integration. Operations performed by modules, programs or other components according to various embodiments may be executed sequentially, in parallel, iteratively or heuristically, or at least some of the operations may be executed in a different order, omitted, or other operations may be added.

Although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and various modifications may be made by those skilled in the art without departing from the gist of the present invention as claimed in the claims. Furthermore, such modifications should not be individually understood from the technical idea or prospect of the present invention.

100: Multi-channel TDMA slot resource integration management, coordination, and sharing system
110: Ship station
120: Coastal station
130: Message distribution device
140: Resource sharing device
210: Communication Module
220: Memory
230: Processor

Claims (8)

In a multi-channel TDMA slot resource integration management system for a maritime VHF band data exchange system,
A message distribution device for distributing messages between coastal stations and resource sharing devices; and
A resource sharing device is provided for receiving dynamic and static information messages generated based on messages received from the coastal station and signal information messages about slot resources used for transmission, and for generating a resource information sharing map matching the resource information map generated from the coastal station using the received dynamic and static information messages and signal information messages.
A multi-channel TDMA slot resource integration management system for a maritime VHF band data exchange system, wherein the resource sharing device receives a resource request message from a ship station within the communication coverage area of the coastal station through the message distribution device, derives available resources from the generated resource information sharing map using the received resource request message, and allocates the derived available resources to the ship station through the message distribution device. In the first paragraph,
Dynamic and static information messages generated based on messages received from the above coastal stations and signaling information messages about slot resources used for transmission,
A multi-channel TDMA slot resource integration management system for a maritime VHF band data exchange system, which generates a resource information sharing map in the form of a table by synthesizing the identification code, separation distance, channel information, slot number used in the corresponding channel, and slot plan to be used in the corresponding channel of the coastal station or ship station. In the first paragraph,
The above resource sharing device,
A multi-channel TDMA slot resource integration management system for a maritime VHF band data exchange system, which generates a resource information sharing map that matches the coast station's AIS (Automatic Identification System) resource information map, ASM (Application Specific Message) resource information map, and VDE (VHF Data Exchange) resource information map by using the received dynamic and static information messages and signal information messages. In the first paragraph,
The above resource sharing device,
A multi-channel TDMA slot resource integrated management system for a maritime VHF band data exchange system, which selects a group of allocatable slot candidates through channel-by-channel slot status analysis from the generated resource information sharing map, and derives available resources by comparing the selected group of slot candidates with a resource information sharing map generated based on information received from an adjacent coastal station having a communication coverage area overlapping with the communication coverage area of the coastal station. In the first paragraph,
The above resource sharing device,
A multi-channel TDMA slot resource integration management system for a maritime VHF band data exchange system, which derives available resource candidates according to communication priority by searching for a free slot state having the same offset constituting a TDMA (Time Division Multiple Access) channel from the above-generated resource information sharing map. In the first paragraph,
The above resource sharing device,
A multi-channel TDMA slot resource integration management system for a maritime VHF band data exchange system, which omits searching for slot states of the same offset constituting a TDMA channel in the ASM resource information map and the VDE resource information map when the slot state of the same offset constituting a TDMA channel in the AIS resource information map with high communication priority is not an empty slot. In the first paragraph,
The above resource sharing device,
A multi-channel TDMA slot resource integration management system for a maritime VHF band data exchange system, which derives the earliest selectable logical channel as an available resource candidate from a TDMA frame in which a selectable logical channel exists following the current TDMA frame in which the above resource request message is received. In Article 7,
The above logical channel is defined as a function of a set of consecutive slots within the same TDMA channel in the horizontal direction, the physical channel is defined by a maritime mobile service band frequency and bandwidth, and each physical channel is linked to one VDE slot map and mapped to one or more logical channels consisting of a BBSC (Bulletin Board Signaling Channel), an ASC (Announcement Signaling Channel), a RAC (Random Access Channel), a DC (Data Channel), and a DSCH (Data Signaling Channel). A multi-channel TDMA slot resource integration management system for a maritime VHF band data switching system.

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