KR102177201B1 - Data transmitting and receiving method, apparatus and system in wireless communication system - Google Patents

Abstract

The present invention relates to a method and an apparatus for transmitting and receiving data by a first terminal in a wireless communication system. According to the present invention, the first terminal forms a connection by using a short distance wireless communication means with a second terminal, and transmits and receives data through a generic attribute profile (GATT) structure of Bluetooth through the formed connection. The first terminal measures an energy level to avoid collision in the connection with the second terminal and, after the connection, can obtain bulk data larger than a size capable of being stored in a characteristic from second data through division.

Description

Data transmission/reception method, device and system in wireless communication system {DATA TRANSMITTING AND RECEIVING METHOD, APPARATUS AND SYSTEM IN WIRELESS COMMUNICATION SYSTEM}

The present invention relates to a wireless communication system, and more particularly, to a method for establishing a connection and a method and an apparatus for transmitting and receiving data using a short-range/long-range wireless communication system.

Bluetooth is a short-range wireless technology standard that can wirelessly connect various devices in a short distance to exchange data. When performing wireless communication between two devices using Bluetooth communication, the user performs a procedure to search for Bluetooth devices to communicate with and request a connection. do. In the present invention, a device may mean a device or a device.

In this case, the user may perform a connection after searching for a Bluetooth device according to a Bluetooth communication method to be used using the Bluetooth device.

Bluetooth communication methods include BR/EDR (Basic Rate/Enhanced Data Rate) method and LE (Low Energy) method, which is a low power method. The BR/EDR method may be referred to as Bluetooth Classic. The Bluetooth classic method includes Bluetooth technology that has been inherited since Bluetooth 1.0 using Basic Rate and Bluetooth technology that uses Enhanced Data Rate supported from Bluetooth 2.0.

Bluetooth Low energy (hereinafter referred to as Bluetooth LE). Applied from Bluetooth 4.0, it can reliably provide hundreds of kilobytes (KB) of information by consuming less power. Protocol) is used to exchange information between devices, which can reduce energy consumption by reducing header overhead and simplifying operation.

Some Bluetooth devices do not have a display or user interface. The complexity of connection / management / control / disconnection between various types of Bluetooth devices and Bluetooth devices to which similar technologies are applied, among others, is increasing.

In addition, Bluetooth can achieve relatively high speed with relatively low power and low cost, but since the transmission distance is generally limited to a maximum of 100 m, it is suitable for use in a limited space.

An object of the present invention is to provide a method and an apparatus for resolving a collision in a channel to which a connection is to be formed in forming a connection using Bluetooth technology.

In addition, an object of the present invention is to provide a method and apparatus for transmitting/receiving by dividing data having a size that cannot be transmitted at a time using Bluetooth technology.

The technical problems to be achieved in the present specification are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those of ordinary skill in the technical field to which the present invention belongs from the following description. I will be able to.

The present invention provides a method and an apparatus performed to transmit and receive data by a first terminal in a wireless communication system for solving the above-described problem.

Specifically, a method performed to transmit and receive data by a first terminal in a wireless communication system according to an embodiment of the present invention is transmitted in a specific channel to form a connection using a near-range wireless communication means with the second terminal. Measuring the energy level of the received signal being received; Determining whether a collision has occurred in the specific channel based on the measured energy level; Establishing a connection with the second terminal based on the measured energy level according to whether the collision occurs; Transmitting a first read request message requesting to read a specific characteristic related to bulk data of a certain size or more to the second terminal, the bulk data consisting of a plurality of data, the specific characteristic Storing first data of the plurality of data; Receiving a first read response message including the first data from the second terminal; Performing a procedure for changing the information stored in the specific characteristic into second data that is next to the first data among the plurality of data; Transmitting a second read request message for requesting to read the specific characteristic to the second terminal; And receiving a second read response message including the second data from the second terminal, wherein the plurality of data is divided from the bulk data based on the size of the specific characteristic.

In addition, in the present invention, the performing of the change procedure may include: transmitting a first write request message for requesting to write a control characteristic for instructing change of information included in the specific characteristic to the second terminal; And receiving a first write response message indicating that the information of the specific characteristic has changed in response to the first write request message from the second terminal, wherein the information included in the first specific characteristic is It is changed from the first data to the second data.

In addition, in the present invention, the first write request message includes at least one of an operation code indicating change of information included in the specific characteristic or counter information indicating information to be changed.

In addition, in the present invention, the specific characteristic includes counter information indicating information included in the specific characteristic or number information indicating the number of the plurality of pieces of data divided from the bulk data.

In addition, the present invention further includes performing a configuration procedure for configuring the bulk data to be stored by the second terminal.

Further, in the present invention, the performing of the configuration procedure includes: transmitting a second write request message requesting to write a second characteristic for instructing the configuration of the bulk data to the second terminal; And receiving the second write response message from the second terminal, wherein the second write request message includes at least one of list information indicating the bulk data or order information indicating a division order of the bulk data. Include.

In addition, the present invention further includes the step of performing a collision resolution procedure with the second terminal when a collision occurs in the specific channel.

In addition, in the present invention, the performing of the collision resolution procedure may include changing a channel when the measured energy level is greater than or equal to a threshold value; Transmitting a trigger packet to a second terminal in the changed channel; And receiving a beacon signal on the changed channel from the second terminal.

In addition, the present invention includes the steps of: transmitting a request message for requesting a connection with the second terminal through Bluetooth to the second terminal through the changed channel; Receiving a confirm message from the second terminal in response to the request message through the changed channel; And changing a state to a semi-connected state for short data transmission, wherein the first terminal stores information related to a Bluetooth connection with the second terminal in the semi-connected state. .

According to an embodiment of the present invention, a terminal may establish a connection and transmit and receive data using a wireless communication system.

In addition, according to an embodiment of the present invention, when a connection is formed using a wireless communication system, when a collision occurs in a channel for connection establishment, the collision is avoided by detecting the energy level in each channel. I can.

Further, according to an embodiment of the present invention, when data is transmitted and received using a wireless communication system, data exceeding a size that can be included in one packet may be divided and transmitted.

In addition, according to the present invention, there is an effect of dividing data exceeding the size of data that can be stored in one characteristic and storing the divided data alternately in one characteristic.

In addition, according to the present invention, by alternately storing data divided into one characteristic, there is an effect of transmitting and receiving data having a large size through one characteristic.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those of ordinary skill in the art from the following description. will be.

1 is a schematic diagram showing an example of a wireless communication system using the Bluetooth low power energy technology proposed in the present specification.
2 shows an example of an internal block diagram of a device capable of implementing the methods proposed in the present specification.
3 is a diagram illustrating an example of a Bluetooth communication architecture to which the methods proposed in the present specification can be applied.
4 is a diagram showing an example of the structure of a Generic Attribute Profile (GATT) of Bluetooth low power energy.
5 is a flowchart illustrating an example of a connection procedure method in Bluetooth low power energy technology to which the present invention can be applied.
6 is a diagram showing a Bluetooth connection procedure.
7 is a diagram showing a Bluetooth process to which the present invention is applied.
FIG. 8 is a flowchart illustrating an example of a method for transmitting and receiving data having a data size of a predetermined size or more in a wireless communication system proposed by the present invention.
9 is a diagram showing an example of a method for dividing data to which the present invention is applied and storing it in one characteristic.

The above objects, features and advantages of the present invention will become more apparent through the following detailed description in conjunction with the accompanying drawings. However, in the present invention, various modifications may be made and various embodiments may be provided. Hereinafter, specific embodiments will be illustrated in the drawings and described in detail. Throughout the specification, the same reference numerals represent the same elements in principle. In addition, when it is determined that a detailed description of known functions or configurations related to the present invention may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

Hereinafter, a method and apparatus related to the present invention will be described in more detail with reference to the drawings. The suffixes "module" and "unit" for components used in the following description are given or used interchangeably in consideration of only the ease of preparation of the specification, and do not have meanings or roles that are distinguished from each other by themselves.

1 is a schematic diagram showing an example of a wireless communication system using the Bluetooth low power energy technology proposed in the present specification.

The wireless communication system 100 includes at least one server device 120 and at least one client device 110.

The server device and the client device perform Bluetooth communication using Bluetooth Low Energy (BLE, hereinafter referred to as'BLE' for convenience) technology.

First, compared to Bluetooth BR/EDR (Basic Rate/Enhanced Data Rate) technology, BLE technology has a relatively small duty cycle, enables low-cost production, and can significantly reduce power consumption through a low-speed data rate. When using a coin cell battery, it can operate for more than 1 year.

In addition, the BLE technology simplifies the connection procedure between devices, and the packet size is designed to be smaller than that of the Bluetooth BR/EDR technology.

In BLE technology, (1) the number of RF channels is 40, (2) the data transmission rate supports 1Mbps, (3) the topology is a scatternet structure, (4) the latency is 3ms, and (5) the maximum current Is less than 15mA, (6) the output power is less than 10mW (10dBm), and (7) is mainly used in applications such as mobile phones, watches, sports, healthcare, sensors, and device control.

The server device 120 may operate as a client device in a relationship with another device, and the client device may operate as a server device in a relationship with another device. That is, in the BLE communication system, any one device can operate as a server device or a client device, and if necessary, it is possible to simultaneously operate as a server device and a client device.

The server device 120 is a data service device, a slave device device, a slave device, a server, a conductor, a host device, a gateway, and a sensing device. It can be expressed as a (Sensing Device), a monitoring device, or the like.

The client device 110 is a master device, a master, a client, a member, a sensor device, a sink device, a collector, a third device, a fourth device, etc. Can be expressed.

The server device and the client device correspond to major components of the wireless communication system, and the wireless communication system may include other components in addition to the server device and the client device.

The server device refers to a device that provides data to the client device through a response when receiving a data request from the client device by receiving data from the client device and performing direct communication with the client device.

In addition, the server device sends a notification message and an indication message to the client device in order to provide data information to the client device. Further, when the server device transmits an indication message to the client device, it receives a confirmation message corresponding to the indication message from the client.

In addition, the server device provides data information to a user through a display unit or receives a request input from a user through an input unit (User Input Interface) in the process of transmitting and receiving notification, instruction, and confirmation messages with the client device. can do.

In addition, the server device may read data from a memory unit or write new data to the memory unit in the process of transmitting and receiving messages with the client device.

In addition, one server device may be connected to a plurality of client devices, and it is possible to easily reconnect (or connect) with the client devices by using bonding information.

The client device 120 refers to a device that requests data information and data transmission from a server device.

The client device receives data from the server device through a notification message, an instruction message, and the like, and when receiving an instruction message from the server device, sends a confirmation message in response to the instruction message.

Similarly, the client device may provide information to a user through an output unit or receive an input from a user through an input unit in a process of transmitting and receiving messages with the server device.

In addition, the client device may read data from a memory or write new data to the memory in a process of transmitting and receiving a message with the server device.

Hardware components such as an output unit, an input unit, and a memory of the server device and the client device will be described in detail with reference to FIG. 2.

In addition, the wireless communication system may configure Personal Area Networking (PAN) through Bluetooth technology. For example, in the wireless communication system, files, documents, and the like can be exchanged quickly and safely by establishing a private piconet between devices.

2 shows an example of an internal block diagram of a device capable of implementing the methods proposed in the present specification.

As shown in FIG. 2, the server device includes an output unit 111, a user input interface 112, a power supply unit 113, a processor 114, and a memory unit. , 115), a Bluetooth interface 116, another communication interface 117, and a communication unit (or a transmission/reception unit 118).

The output unit 111, the input unit 112, the power supply unit 113, the processor 114, the memory 115, the Bluetooth interface 116, the other communication interface 117 and the communication unit 118 are proposed in this specification. To do how to do it is functionally linked.

In addition, the client device includes an output unit (Display Unit, 121), an input unit (User Input Interface, 122), a power supply unit (123), a processor (Processor, 124), a memory unit (125), and a Bluetooth interface. (Bluetooth Interface, 126) and a communication unit (or transceiver, 127).

The output unit 121, the input unit 122, the power supply unit 123, the processor 124, the memory 125, the Bluetooth interface 126, and the communication unit 127 are used to perform the method proposed in this specification. Functionally connected.

The Bluetooth interfaces 116 and 126 refer to a unit (or module) capable of transmitting request/response, command, notification, instruction/confirmation message, etc. or data between devices using Bluetooth technology.

The memories 115 and 125 are units implemented in various types of devices, and refer to units in which various types of data are stored.

The processors 114 and 124 refer to modules that control the overall operation of a server device or a client device, and control to process a message transmission request and a received message through a Bluetooth interface and other communication interfaces.

The processors 114 and 124 may be expressed as a control unit, a control unit, and a controller.

The processors 114 and 124 may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit, and/or a data processing device.

The processors 114 and 124 control the communication unit to receive an advertising message from a server device, transmit a scan request message to the server device, and scan in response to the scan request from the server device. Controls the communication unit to receive a Scan Response message, and controls the communication unit to transmit a Connect Request message to the server device to establish a Bluetooth connection with the server device.

In addition, the processor (114, 124) after the Bluetooth LE connection (Connection) is formed through the connection procedure, the communication unit to read (Read) or write (Write) data using the property protocol from the server device. Control.

The memories 115 and 125 may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium, and/or other storage device.

The communication units 118 and 127 may include a baseband circuit for processing a radio signal. When the embodiment is implemented in software, the above-described technique may be implemented as a module (process, function, etc.) that performs the above-described functions. The modules are stored in memory and can be executed by the processor.

The memories 115 and 125 may be inside or outside the processors 114 and 124, and may be connected to the processors 114 and 124 by various well-known means.

The output units 111 and 121 refer to modules for providing device status information and message exchange information to a user through a screen.

The power supply unit (power supply unit, 113, 123) refers to a module that receives external power and internal power under the control of a control unit and supplies power necessary for the operation of each component.

As mentioned earlier, BLE technology has a small duty cycle, and power consumption can be greatly reduced through a low data rate.

The input units 112 and 122 refer to a module that provides a user's input to the controller, such as a screen button, so that the user can control the operation of the device.

3 is a diagram illustrating an example of a Bluetooth communication architecture to which the methods proposed in the present specification can be applied.

Referring to FIG. 3, (a) of FIG. 3 shows an example of a protocol stack of Bluetooth Basic Rate (BR)/Enhanced Data Rate (EDR), and (b) is a protocol stack of Bluetooth Low Energy (LE). Shows an example of.

Specifically, as shown in (a) of FIG. 3, the Bluetooth BR/EDR protocol stack is based on a host controller interface (HCI, 18). It may include a host stack (20).

The host stack (or host module) 20 refers to a wireless transmission/reception module that receives a 2.4 GHz Bluetooth signal and a hardware for transmitting or receiving a Bluetooth packet, and is connected to a Bluetooth module that is the controller stack 10 to provide a Bluetooth module. Control and perform actions.

The controller stack 10 may include a PHY layer 12, a link controller layer 14, and a link manager layer 16.

The PHY layer 12 is a layer that transmits and receives a 2.4GHz radio signal, and when using GFSK (Gaussian Frequency Shift Keying) modulation, data can be transmitted by hopping 79 RF channels.

The link controller layer 14 plays a role of transmitting a digital signal, selects a channel sequence hopping 1400 times per second, and transmits a time slot of 625us length for each channel.

The link manager layer 16 controls the overall operation (link setup, control, and security) of the Bluetooth connection using LMP (Link Manager Protocol).

The link manager layer 16 may perform the following functions.

-ACL/SCO logical transport, logical link setup and control.

-Detach: Disconnects the connection and informs the other device of the reason for the suspension.

-Power control and role switch.

-Performs security (authentication, pairing, encryption) function.

The host controller interface layer 18 provides an interface between the host module and the controller module so that the host provides commands and data to the controller, and the controller provides events and data to the host.

The host stack (or host module, 20) includes a logical link control and adaptation protocol (L2CAP, 21), an attribute protocol (Protocol, 22), a generic attribute profile (GATT, 23), and a generic access profile (Generic Access). Profile, GAP, 24), and BR/EDR profile 25.

The logical link control and adaptation protocol (L2CAP, 21) may provide one bidirectional channel for transmitting data to a specific protocol or profile.

The L2CAP 21 may multiplex various protocols, profiles, etc. provided by the upper level of Bluetooth.

The L2CAP of Bluetooth BR/EDR uses a dynamic channel, supports protocol service multiplexer, retransmission, and streaming mode, and provides segmentation and reassembly, per-channel flow control, and error control.

The general attribute profile (GATT, 23) may be operable as a protocol that describes how the attribute protocol 22 is used when configuring services. For example, the general attribute profile 23 may be operable to specify how ATT attributes are grouped together into services, and may be operable to describe features associated with services.

Thus, the general attribute profile 23 and the attribute protocol ATT 22 can use features to describe the state and services of a device, and how features relate to each other and how they are used.

The attribute protocol 22 and the BR/EDR profile 25 define a service (profile) using Bluetooth BR/EDR and an application protocol for sending and receiving these data, and the generic access profile (Generic Access Profile) , GAP, 24) defines the device discovery, connection, and security level.

As shown in (b) of FIG. 4, the Bluetooth LE protocol stack includes a controller stack 30 operable to process a wireless device interface where timing is important, and a host operable to process high level data. Includes the Host stack (40).

First, the controller stack 30 may be implemented using a communication module that may include a Bluetooth wireless device, for example, a processor module that may include a processing device such as a microprocessor.

The host stack can be implemented as part of an OS running on a processor module, or as an instantiation of a package on the OS.

In some instances, the controller stack and the host stack may operate or run on the same processing device within a processor module.

The controller stack 30 includes a physical layer (PHY, 32), a link layer (34), and a host controller interface (36).

The physical layer (PHY, wireless transmission/reception module, 32) is a layer that transmits and receives a 2.4 GHz radio signal, and uses GFSK (Gaussian Frequency Shift Keying) modulation and a frequency hopping technique composed of 40 RF channels.

The link layer 34, which transmits or receives Bluetooth packets, creates a connection between devices after performing advertising and scanning functions using three advertising channels, and data packets of up to 257 bytes through 37 data channels. It provides the function of sending and receiving.

The host stack is a logical link control and adaptation protocol (L2CAP, 41), a security manager (Security Manager, SM, 42), an attribute protocol (Attribute Protocol, ATT, 43), and a generic attribute profile (GATT, 44). , Generic Access Profile (45), may include a LE profile (46). However, the host stack 40 is not limited thereto and may include various protocols and profiles.

The host stack uses L2CAP to multiplex various protocols and profiles provided by the upper level of Bluetooth.

First, L2CAP (Logical Link Control and Adaptation Protocol, 41) may provide one bidirectional channel for transmitting data to a specific protocol or profile.

The L2CAP 41 may be operable to multiplex data between higher layer protocols, segment and reassemble packages, and manage multicast data transmission.

In Bluetooth LE, 3 fixed channels (1 for signaling CH, 1 for Security Manager, 1 for Attribute protocol) are basically used. And, if necessary, a dynamic channel may be used.

On the other hand, in BR/EDR (Basic Rate/Enhanced Data Rate), a dynamic channel is basically used, and protocol service multiplexer, retransmission, and streaming mode are supported.

SM (Security Manager, 42) is a protocol for authenticating devices and providing key distribution, and is responsible for overall security of Bluetooth LE.

ATT (Attribute Protocol, 43) defines a rule for accessing data of a counterpart device in a server-client structure. ATT has the following 6 message types (Request, Response, Command, Notification, Indication, Confirmation).

① Request and Response message: Request message is a message for requesting and delivering specific information from a client device to a server device, and a response message is a response message to a request message, which can be used for transmission from a server device to a client device. Say.

② Command message: This is a message sent mainly to instruct a command for a specific operation from a client device to a server device. The server device does not transmit a response to the command message to the client device.

③ Notification message: This message is sent from the server device to the client device for notification such as an event, and the client device does not send a confirmation message for the notification message to the server device.

④ Indication and Confirm message: This message is sent from the server device to the client device for notification such as an event. Unlike the Notification message, the client device transmits a Confirm message for the Indication message to the server device.

The general access profile 45 is a layer newly implemented for Bluetooth LE technology, and is used to select a role for communication between Bluetooth LE devices and control how a multi-profile operation occurs.

In addition, the general access profile 45 is mainly used for device discovery, connection creation, and security procedures, defines a method of providing information to a user, and defines the following attribute types.

① Service: Defines the basic operation of the device as a combination of data-related behavior

② Include: Define the relationship between services

③ Characteristics: Data value used in service

④ Behavior: A computer-readable format defined as UUID (Universal Unique Identifier, value type)

The LE profile 46 is a profile dependent on GATT and is mainly applied to a Bluetooth LE device. The LE profile 46 may include, for example, Battery, Time, FindMe, Proximity, Time, and the like, and specific contents of GATT-based Profiles are as follows.

① Battery: How to exchange battery information

② Time: How to exchange time information

③ FindMe: Provides alarm service according to distance

④ Proximity: How to exchange battery information

⑤ Time: How to exchange time information

The general attribute profile GATT 44 may operate as a protocol describing how the attribute protocol 43 is used when configuring services. For example, the general attribute profile 44 may be operable to specify how ATT attributes are grouped together into services, and may be operable to describe features associated with services.

Thus, the general attribute profile 44 and the attribute protocol (ATT, 43) can use features to describe the state and services of a device and to describe how features are related to each other and how they are used.

Hereinafter, procedures of Bluetooth Low Energy (BLE) technology will be briefly described.

The BLE procedure can be classified into a device filtering procedure, an advertising procedure, a scanning procedure, a discovery procedure, and a connecting procedure.

Device Filtering Procedure

The device filtering procedure is a method for reducing the number of devices that respond to requests, instructions, and notifications in the controller stack.

When all devices receive a request, it is unnecessary to respond to it, so the controller stack can control the BLE controller stack to reduce power consumption by reducing the number of transmitting requests.

The advertising device or scanning device may perform the device filtering procedure to limit devices that receive an advertisement packet, a scan request, or a connection request.

Here, the advertisement device refers to a device that transmits an advertisement event, that is, performs advertisement, and is also referred to as an advertiser.

The scanning device refers to a device that performs scanning and a device that transmits a scan request.

In BLE, when a scanning device receives some advertisement packets from an advertisement device, the scanning device must transmit a scan request to the advertisement device.

However, if the device filtering procedure is used and thus the transmission of the scan request is unnecessary, the scanning device may ignore advertisement packets transmitted from the advertisement device.

The device filtering procedure can also be used in the connection request process. If device filtering is used in the connection request process, it is not necessary to transmit a response to the connection request by disregarding the connection request.

Advertising Procedure

The advertisement device performs an advertisement procedure to perform non-directional broadcast to devices in the area.

Here, non-directional broadcast refers to broadcast in all (all) directions, not broadcast in a specific direction.

In contrast, directional broadcast refers to broadcast in a specific direction. Non-directional broadcast occurs without a connection procedure between an advertisement device and a device in a listening (or listening) state (hereinafter, referred to as a listening device).

The advertising procedure is used to establish a Bluetooth connection with a nearby initiating device.

Alternatively, the advertisement procedure may be used to provide periodic broadcast of user data to scanning devices that are listening on the advertisement channel.

In the advertisement procedure, all advertisements (or advertisement events) are broadcast through advertisement physical channels.

The advertisement devices may receive scan requests from listening devices that are listening to obtain additional user data from the advertisement device. The advertisement device transmits a response to the scan request to the device that transmitted the scan request through the same advertisement physical channel as the advertisement physical channel receiving the scan request.

Broadcast user data sent as part of advertisement packets is dynamic data, while scan response data is generally static data.

The advertising device may receive a connection request from the initiating device on the advertising (broadcast) physical channel. If the advertisement device uses a connectable advertisement event and the initiating device is not filtered by the device filtering procedure, the advertisement device stops advertisement and enters a connected mode. The advertising device may start advertising again after the connected mode.

Scanning Procedure

A device performing scanning, that is, a scanning device, performs a scanning procedure to listen to a non-directional broadcast of user data from advertisement devices using an advertisement physical channel.

The scanning device transmits a scan request to the advertisement device through an advertisement physical channel in order to request additional data from the advertisement device. The advertisement device transmits a scan response, which is a response to the scan request, including additional data requested by the scanning device through the advertisement physical channel.

The scanning procedure may be used while being connected to other BLE devices in the BLE piconet.

If the scanning device receives a broadcast advertisement event and is in an initiator mode capable of initiating a connection request, the scanning device transmits a connection request to the advertisement device through the advertisement physical channel. And you can start a Bluetooth connection.

When the scanning device transmits a connection request to the advertisement device, the scanning device stops scanning the initiator mode for additional broadcast and enters the connection mode.

Discovering Procedure

Devices capable of Bluetooth communication (hereinafter, referred to as'Bluetooth devices') perform an advertisement procedure and a scanning procedure to discover nearby devices or to be discovered by other devices within a given area.

The discovery procedure is performed asymmetrically. A Bluetooth device that tries to find other devices around it is called a discovery device, and listens to find devices that advertise scannable advertising events. A Bluetooth device that is discovered and available from another device is called a discoverable device, and actively broadcasts an advertisement event so that other devices can scan through an advertisement (broadcast) physical channel.

Both the discovering device and the discoverable device may already be connected to other Bluetooth devices in the piconet.

Connecting Procedure

The connection procedure is asymmetric, and the connection procedure requires that a specific Bluetooth device perform an advertisement procedure while another Bluetooth device performs a scanning procedure.

That is, the advertising procedure may be the goal, and as a result, only one device will respond to the advertisement. After receiving an advertisement event accessible from the advertisement device, the connection may be initiated by transmitting a connection request to the advertisement device through an advertisement (broadcast) physical channel.

Next, an operation state in BLE technology, that is, an advertising state, a scanning state, an initiating state, and a connection state will be briefly described.

Advertising State

The link layer (LL) enters the advertisement state by the instruction of the host (stack). When the link layer is in the advertisement state, the link layer transmits advertisement packet data units (PDUs) in advertisement events.

Each advertisement event consists of at least one advertisement PDU, and advertisement PDUs are transmitted through used advertisement channel indexes. The advertisement event may be terminated when each transmitted through advertisement channel indexes in which the advertisement PDU is used, or when the advertisement device needs to reserve space for performing other functions, the advertisement event may be terminated earlier.

Scanning State

The link layer enters the scanning state by the instruction of the host (stack). In the scanning state, the link layer listens for advertisement channel indexes.

There are two types of scanning states: passive scanning and active scanning, and each scanning type is determined by the host.

A separate time or advertisement channel index for performing scanning is not defined.

During the scanning state, the link layer listens for the advertisement channel index during the scanWindow duration. The scanInterval is defined as the interval (interval) between the starting points of two consecutive scan windows.

If there is no scheduling conflict, the link layer must listen to complete all scan intervals of the scan window as indicated by the host. In each scan window, the link layer must scan a different advertising channel index. The link layer uses all available advertising channel indices.

In passive scanning, the link layer only receives packets and cannot transmit any packets.

In the case of active scanning, the link layer performs listening to rely on the advertisement PDU type that can request advertisement PDUs and additional information related to the advertisement device to the advertisement device.

Initiating State

The link layer enters the start state by the instruction of the host (stack).

When the link layer is in the initiated state, the link layer listens for advertisement channel indexes.

During the start state, the link layer listens for the advertisement channel index during the scan window period.

Connection state

The link layer enters the connected state when the device performing the connection request, that is, when the initiating device transmits a CONNECT_REQ PDU to the advertisement device or when the advertisement device receives a CONNECT_REQ PDU from the initiating device.

After entering the connected state, the connection is considered to be created. However, it does not need to be considered to be established when the connection enters the connected state. The only difference between a newly created connection and an established connection is the link layer connection supervision timeout value.

When two devices are connected, the two devices act in different roles.

The link layer that plays the role of a master is called a master, and the link layer that plays the role of a slave is called a slave. The master controls the timing of the connection event, and the connection event refers to the timing of synchronization between the master and the slave.

Hereinafter, a packet defined in the Bluetooth interface will be briefly described. BLE devices use packets defined below.

Packet Format

The Link Layer has only one packet format used for both advertising channel packets and data channel packets.

Each packet is composed of four fields: Preamble, Access Address, PDU and CRC.

When one packet is transmitted on an advertisement physical channel, the PDU will be an advertisement channel PDU, and when one packet is transmitted on a data physical channel, the PDU will be a data channel PDU.

Advertising Channel PDU (Advertising Channel PDU)

The advertisement channel PDU (Packet Data Unit) has a 16-bit header and payloads of various sizes.

The PDU type field of the advertisement channel PDU included in the header indicates the PDU type as defined in Table 1 below.

PDU Type Packet Name 0000 ADV_IND 0001 ADV_DIRECT_IND 0010 ADV_NONCONN_IND 0011 SCAN_REQ 0100 SCAN_RSP 0101 CONNECT_REQ 0110 ADV_SCAN_IND 0111-1111 Reserved

The advertisement channel PDU types under the advertisement PDU (Advertising PDU) are called advertisement PDUs and are used in specific events.

ADV_IND: Connectable non-directional advertising event

ADV_DIRECT_IND: Connectable directional ad event

ADV_NONCONN_IND: Non-directed advertising event that is not connectable

ADV_SCAN_IND: scannable non-directional advertising event

The PDUs are transmitted in a link layer in an advertisement state, and received by a link layer in a scanning state or an initiating state.

Scanning PDU (Scanning PDU)

The advertisement channel PDU type below is called a scanning PDU and is used in the state described below.

SCAN_REQ: Sent by the link layer in the scanning state, and received by the link layer in the advertisement state.

SCAN_RSP: transmitted by the link layer in the advertisement state, and received by the link layer in the scanning state.

Initiating PDU (Initiating PDU)

The advertisement channel PDU type below is called an initiating PDU.

CONNECT_REQ: transmitted by the link layer in the initiating state, and received by the link layer in the advertisement state.

Data Channel PDU (Data Channel PDU)

The data channel PDU has a 16-bit header, payloads of various sizes, and may include a Message Integrity Check (MIC) field.

The procedure, state, packet format, etc. in the BLE technology described above can be applied to perform the methods proposed in this specification.

4 is a diagram showing an example of the structure of a Generic Attribute Profile (GATT) of Bluetooth low power energy.

Referring to FIG. 4, a structure for exchanging profile data of Bluetooth low power energy can be described.

Specifically, GATT (Generic Attribute Profile) defines a method of exchanging data using service and characteristic between Bluetooth LE devices.

In general, a peripheral device (for example, a sensor device) acts as a GATT server, has definitions for service and characteristics, and a central device is a GATT server. It acts as a client.

In order to read or write data, the GATT client sends a data request to the GATT server, and all transactions are initiated by the GATT client and receive a response from the GATT server.

The GATT-based operation structure used in Bluetooth LE is based on a profile, a service, and a characteristic, and may form a vertical structure as shown in FIG. 5.

The Profile is composed of one or more services, and the service may be composed of one or more characteristics or other services.

The service serves to divide data into logical units, and may include one or more characteristics or other services. Each service has a 16bit or 128bit identifier called UUID (Universal Unique Identifier).

The characteristic is the lowest unit in the GATT-based operation structure. The feature contains only one piece of data, and similarly to the service, it has a 16-bit or 128-bit UUID.

The characteristic is defined as a value of various types of information, and one attribute is required to contain each information. Several consecutive attributes can be used.

The attribute is composed of four components and has the following meaning.

-handle: the address of the property

-Type: type of attribute

-Value: the value of the attribute

-Permission: permission to access properties

5 is a flowchart illustrating an example of a connection procedure method in Bluetooth low power energy technology to which the present invention can be applied.

The server transmits an advertisement message to the client through three advertisement channels (S5010).

The server may be referred to as an advertiser before connection, and may be referred to as a master after connection. As an example of the server, there may be a sensor (such as a temperature sensor).

In addition, the client may be referred to as a scanner before connection, and may be referred to as a slave after connection. An example of a client may be a smart phone.

As discussed earlier, Bluetooth communicates by being divided into a total of 40 channels through the 2.4GHz band. Three of the 40 channels are advertisement channels, and are used for exchange of packets exchanged for establishing a connection, including various advertisement packets.

The remaining 37 channels are used for data exchange after connection to the data channel.

After receiving the advertisement message, the client may transmit a Scan Request message to the server to obtain additional data (eg, server device name) to the server.

In this case, the server transmits a Scan Response message including additional data to the client in response to the Scan Request message.

Here, the Scan Request message and Scan Response message are one end of the advertisement packet, and the advertisement packet may include only 31 bytes or less of User Data.

Therefore, if the size of the data is larger than 3 bytes, but there is data that has a large overhead to send the data by connecting it, the data is divided and sent twice using the Scan Request message/Scan Response message.

Next, the client transmits a Connection Request message for establishing a Bluetooth connection with the server to the server (S5020).

Through this, a Link Layer (LL) connection is established between the server and the client.

After that, the server and the client perform a security establishment procedure.

The security establishment procedure can be interpreted as or performed by including Secure Simple Pairing.

That is, the security establishment procedure may be performed through Phase 1 to Phase 3.

Specifically, a pairing procedure (Phase 1) is performed between the server and the client (S5030).

In the pairing procedure, the client transmits a Pairing Request message) to the server, and the server transmits a Pairing Response message to the client.

Through the pairing procedure, authentication requirements, I(Input)/O(Output) capabilities, and Key Size information are exchanged between devices. With this information, it is decided which key generation method to use in Phase 2.

Next, as Phase 2, legacy pairing or secure connection between the server and the client is performed (S5040).

In Phase 2, a 128bits Temporary Key and Short Term Key (STK) that performs legacy pairing are created.

-Temporary Key: Key created to create STK

-Short Term Key (STK): Key value used to create an encrypted connection between devices

If secure connection is performed in Phase 2, a 128 bit Long Term Key (LTK) is generated.

-Long Term Key (LTK): Key value used not only for encrypted connection between devices but also for future connection

Next, as SSP Phase 3, a key distribution procedure is performed between the server and the client (S5050).

Through this, a secure connection is established between the server and the client, and data can be transmitted and received by forming an encrypted link.

Hereinafter, a method for transmitting and receiving a long attribute value will be described.

The longest attribute that can be transmitted in a single packet is ATT_MTU-1 octet. Here, ATT_MTU means the maximum size of a packet transmitted between the client and the server.

At a minimum, the Attribute Opcode is included in the Attribute PDU. The attribute value can be defined larger than ATT_MTU-1 octet, and this attribute is called a long attribute.

In order to read the entire value of an attribute larger than ATT_MTU-1 octet, a Read Blob Request message is used. The read request message can be used to read the first ATT_MTU-1 octet of the long attribute value.

A ready write request message and an execution write request message can be used to write the entire value of an attribute larger than ATT_MTU-3 octets. The write request message can be used to write the first ATT_MTU-3 octet of the long attribute value.

It is difficult to determine if the attribute value is longer than ATT_MTU-3 octets using a specific protocol. The upper layer specification specifies that a given attribute can have a maximum length greater than ATT_MTU-3 octets.

The maximum length of the attribute value is 512 octet. That is, the maximum length of data that can be stored in one characteristic is 512 octet.

However, when data exceeding the maximum length that can be stored in one characteristic occurs, there is no method for transmitting and receiving data through the ATT Protocol.

Accordingly, in order to solve this problem, the present invention proposes a method for transmitting and receiving data through one characteristic by dividing data when the maximum length that can be stored in one characteristic is exceeded.

6 is a diagram showing a Bluetooth connection procedure.

The Bluetooth pairing procedure is divided into Standby State and Connected State only, and the device after pairing is in the Connected State, and the connected device is operated in the Standby State. do.

Even when the Bluetooth devices are connected to a specific device through the connection process (S410) and then reconnect (S420) to reconnect later, they attempt to connect through the same procedure as the previous connection process (S410).

Specifically, the Human Input Device (Human Input Device, 200) basically enters the standby state when power is supplied, and then the Inquiry State (Inquiry State) to discover nearby connectable devices. ), and the host 100 may enter an Inquiry Scan State in order to receive an ID packet transmitted by a nearby device in an Inquiry state.

The human input device 200 that has entered the inquiry state transmits an inquiry message using an ID packet once or at predetermined time intervals in order to discover devices that can be connected to the surroundings (S412).

The ID packet may be a General Inquiry Access Code (GIAC) or a Dedicated Inqury Access Code (DIAC).

After receiving the GIAC or DIAC, which is an ID packet transmitted by the host device 100, the human input device 200 sends a frequency hopping sequence to the host device 100 in order to perform Bluetooth pairing with the host device 100. (Frequency Hoppinf Sequence, FHS) can be transmitted, and if necessary, for example, when there is data to be transmitted, an extended inquiry response (hereinafter referred to as EIR) can be transmitted.

If a connectable Bluetooth device is found in the vicinity through the inquiry procedure, a paging procedure may be performed. The paging procedure refers to a step of performing an actual connection by synchronizing a hopping sequence with an address and clock information when a nearby connectable Bluetooth device is found through the inquiry procedure.

The host device 100 and the human input device 200 that performed the connection go through an L2CAP connection and service discovery step through a security establishment step (S414) (S416).

The L2CAP (Logical Link Control and Adaption Protocol) is a packet-based protocol and has similar characteristics to the UDP protocol. It has a packet size of up to 672 bytes by default, but can be changed up to 65,535 bytes when communication starts.

The human input device 200 that has passed through the L2CAP connection and service discovery step (S416) may transmit data to the host device 100 (S418).

If there is no data exchange between the human input device 200 and the host device 100 through the connection process (S410) as described above, the Bluetooth module is converted into a sleep state to prevent energy consumption. The state ends.

Thereafter, in order for the human input device 200 and the host device 100 to transmit/receive data again, a reconnection process (S420) must be performed, and this reconnection process (S420) includes the connection process (S410) and It can be performed through the same procedure.

However, if the reconnection process occurs frequently, a delay may occur, and performing the same process as the initial connection to reconnect to the same device reduces efficiency and user convenience. Therefore, a method capable of solving these problems will be described below.

7 is a diagram showing a Bluetooth process to which the present invention is applied.

Referring to FIG. 7, (a) the current Bluetooth BR/EDR process does not have a reconnection procedure, and all devices are in a connected state through paging (Connected State, 514), and a standby state due to connection termination (512 ) Can be separated.

When the connected state 514 and the standby state 512 are classified as described above, a device that is not used for a certain period of time enters the standby state 512 and then performs a new paging step at the point of being used again. After that, it may take a long time to enter the connect state 514.

(b) In the Bluetooth process proposed in the present invention, only the device attempting the first Bluetooth connection stays in the standby state 522, and the device that has connected at least once goes to the suspend state 524 instead of the standby state 522. You can enter.

Unlike the standby state 522, the suspend state 524 stores a connection history including a unique address (hereinafter referred to as BD_ADDR) and an LT_ADDR (Logical Transport Address) of the host device assigned to it, and reconnection is performed. If possible, after entering the semi-connect state 526 for quick pairing, the connect state 528 may be entered only when continuous use is required.

The semi-connect state 526 may represent an intermediate step between the standby state 522 and the connect state 528, and may represent a temporary state for quickly transmitting short event data.

A procedure for transitioning from the suspended state 524 to the semi-connected state 526 or transitioning from the standby state 522 to the semi-connected state 526 is hereinafter referred to as FPPS (Fast Pre-Paging Scheme). .

Through the FPPS, the Bluetooth device may have basic information for reconnecting with the device once connected, and can quickly reconnect with the device once connected based on the basic information.

Hereinafter, a connection method and a data transmission/reception method in a wireless communication system proposed by the present invention will be described.

FIG. 8 is a flowchart illustrating an example of a method for transmitting and receiving data having a data size of a predetermined size or more in a wireless communication system proposed by the present invention.

Referring to FIG. 8, when a client (terminal 1) establishes a connection with a server (terminal 2), it can enter a specific state for reconnection, and divide the data to transmit and receive data of a certain size or more. You can switch to and save.

First, the first terminal may establish a connection with the second terminal using a long-distance and/or short-range wireless communication means.

Specifically, the energy level of a received signal transmitted through a specific channel may be measured in order to establish a connection using a near-range wireless communication means (S8010). In this case, the energy level may be measured through an energy detection process. Energy detection is for measuring the power of a signal received by the first terminal through a specific channel (here, energy may mean the power of the received signal), and the received signal communicates between the first terminal and the second terminal. It can be performed to determine whether or not it may cause interference.

Thereafter, the first terminal can determine whether a collision has occurred in a specific channel based on the measured energy level (S8020), and connects with the second terminal based on the measured energy level according to whether a collision has occurred. Can be formed (S8030).

Whether a collision occurs in a specific channel may be determined by whether the measured energy level exceeds a threshold value. That is, if the measured energy level is less than the threshold value, the first terminal determines that interference (e.g., Inter-Interference) does not occur, and transmits a trigger packet to perform a connection or reconnection procedure. I can.

However, if the measured energy level is greater than the threshold value, the terminal may determine that a collision or inter-interference with another network using the same band has occurred in the channel, and may perform a procedure for resolving the collision.

In the collision resolution procedure, when the energy level of a signal measured in a specific channel exceeds or exceeds a threshold value, the energy level is measured by changing a specific channel to another channel.

If the energy level measured in the changed channel exceeds the threshold value again, the channel is changed again, and if the energy level measured in the changed channel does not exceed the threshold value, a trigger packet is transmitted to the second terminal in the changed channel.

Thereafter, the first terminal may receive a beacon signal from the second terminal in response to the trigger packet on the changed channel, and transmit a request message to the second terminal to request a connection with the second terminal through Bluetooth through the changed channel. have.

Thereafter, the first terminal may receive a confirmation message in response to the request message in order to establish a connection with the second terminal, and change the state to a semi-connected state for transmitting short data. .

The semi-connected state is a state in which information for establishing a connection with the second terminal is stored, and the first terminal can transmit and receive not only data for establishing a connection with the second terminal, but also data of a short size. .

After establishing a connection with the second terminal, the first terminal may transmit and receive data through the GATT structure described in FIG. 4.

Specifically, the first terminal may transmit a first read request message requesting to read a specific characteristic related to bulk data of a predetermined size or more to the second terminal (S8040).

Here, the bulk data refers to data having a size that exceeds the size of data that can be stored in a characteristic in the GATT structure and/or the size of the payload that can be transmitted through one message, and the size of the characteristic And/or it may be divided according to the size of the payload and composed of a plurality of data. As an example of bulk data, association data of the first terminal and/or the second terminal may exist.

A counting number or index may be assigned to the plurality of pieces of data to distinguish an order, and a specific characteristic may store one of the plurality of pieces of data according to the counting number or index. For example, a specific characteristic may store first data, which is the first data among a plurality of data of bulk data.

Thereafter, the first terminal may receive a first read response message including the first data from the second terminal (S8050), and information stored in a specific characteristic is the next data of the first data among the plurality of data. A procedure for changing to the second data may be performed (S8060).

The procedure for changing data is a procedure for changing (or switching) the data stored in a specific specific data to the next data among a plurality of data, and the first terminal is the second terminal to change the information included in the specific characteristic. It is possible to transmit a first write request message requesting to write a control characteristic for indicating.

Thereafter, upon receiving the first write request message from the first terminal, the second terminal deletes the first data stored in the specific characteristic, and stores second data, which is the next data of the first data, in the specific characteristic.

When the data change of the specific characteristic is completed, the second terminal transmits a first write response message indicating that the information of the specific characteristic has changed in response to the first write request message to the first terminal.

The first write request message may include at least one of an operation code indicating change of information included in a specific characteristic or counter information indicating information to be changed, and the specific characteristic is counter information indicating information included in a specific characteristic Alternatively, number information indicating the number of the plurality of pieces of data divided from the bulk data may be included.

In order to obtain the second data changed from the first data, the first terminal may transmit a second read request message requesting the second terminal to read a specific characteristic (S8070), and the second data is included in response thereto. The second read response message to be read may be received (S8080).

Through such a data transmission/reception method, even large data including a large number of pieces of information can be stored alternately in specific characteristics through division, through which the terminal can transmit and receive data.

In this case, a configuration procedure for configuring bulk data to be stored by the second terminal may be performed before additional data is transmitted and received.

Specifically, the first terminal transmits a second write request message to the second terminal requesting the writing of a second characteristic for indicating the configuration of bulk data having a size of a certain size or more, and a second write response message in response thereto. Can receive.

The second write request message may include at least one of list information indicating the bulk data or order information indicating a division order of the bulk data.

9 is a diagram showing an example of a method for dividing data to which the present invention is applied and storing it in one characteristic.

Referring to FIG. 9, when specific data exceeds a size that can be stored in one characteristic, the server may divide the specific data into a plurality of data and store it in the characteristic.

Hereinafter, a case where specific data is related information including device connection information, pairing information and/or bonding information will be described as an example.

Specifically, the η server may configure association information to be stored in a characteristic among all association information. In the configuration of the related information, configuration information related to the configuration of the related information may be received from the client or the server may directly configure the related information.

For example, when the server receives configuration information related to the configuration of the connection information among the related information from the client, the server acquires and configures only connection information related to the connected device. Through this, the server device may obtain and configure related information of all devices associated with it, or obtain and configure related information including at least one of connection information, bonding information, and/or pairing information.

When the configured related information exceeds the maximum size that can be stored in one characteristic, the server may divide the configured related information into a plurality of data according to the maximum size. Hereinafter, each of the divided data will be referred to as a bank.

② After that, the server selects each divided bank in order and stores it in the properties. In other words, divided banks are selected in a specific order, and the selected bank is stored in the related characteristics (hereinafter, related state characteristics). When the server receives a message requesting the attribute value of the association state characteristic from the client, the server transmits the attribute value of the association state characteristic to the client through read response or read blob response messages. When the server transmits all the attribute values of the associated state characteristic to the client, it selects the next bank in a specific order and updates (or replaces) the attribute attribute values with the selected bank.

For example, when the server receives a write request message requesting the entry of a specific characteristic (eg, control point characteristic) instructing the replacement of the attribute value of the characteristic from the client, the attribute value of the associated state characteristic is transferred to another bank. And send a write response message notifying that the attribute value of the associated state property has changed to the client.

In this case, the client may change the attribute value of the association state characteristic to the specific bank regardless of the order by including and transmitting a value indicating the bank to be changed (eg, a specific number of the order) in the write request message.

After changing the attribute value of the associated state characteristic, when the server receives a read response or read blob response message requesting the changed attribute value of the associated state characteristic from the client, it is changed through the read response message or the read blob response message to the client. Property values can be sent to the client.

When data exceeding the maximum size that can be stored in one characteristic occurs, data can be divided according to the maximum size and stored in one characteristic, and the divided data can be stored alternately in one characteristic in a specific order. Data exceeding the maximum size can be transmitted to the client through one characteristic.

The above description of the present invention is for illustrative purposes only, and those of ordinary skill in the art to which the present invention pertains will be able to understand that other specific forms can be easily modified without changing the technical spirit or essential features of the present invention will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as being distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. do.

Claims (9)

In a method performed to transmit and receive data by a first terminal in a wireless communication system,
Measuring an energy level of a received signal transmitted through a specific channel to establish a connection between the second terminal and the near-range wireless communication means;
Determining whether a collision has occurred in the specific channel based on the measured energy level;
Establishing a connection with the second terminal based on the measured energy level according to whether the collision occurs; And
Transmitting a second write request message for requesting to write a second characteristic for instructing the configuration of specific information related to connection information used for reconnection with the second terminal to the second terminal;
Receiving the second write response message from the second terminal;
The second write request message includes at least one of list information indicating the specific information or order information indicating a division order of the specific information,
Including the step of transmitting and receiving the specific information to the second terminal,
When the size of the specific information is larger than the size that can be stored in the characteristic of the second terminal, transmitting and receiving the specific information,
Transmitting a first read request message requesting to read a specific characteristic related to some data of the specific information to the second terminal,
The partial data is one of a plurality of pieces of data in which the specific information is divided into equal sizes,
The specific characteristics are sequentially stored according to an index order among the plurality of data;
Receiving a first read response message including the partial data from the second terminal;
Performing a procedure for changing the partial data stored in the specific characteristic into the next partial data having a next index value of the partial data among the plurality of data;
Transmitting a second read request message requesting to read the specific characteristic to the second terminal; And
Receiving a second read response message including the following partial data from the second terminal,
The method of dividing the plurality of data based on the size of the specific characteristic.
The method of claim 1, wherein performing the change procedure comprises:
Transmitting a first write request message requesting to write a control characteristic for instructing to change the partial data included in the specific characteristic to the second terminal; And
Further comprising the step of receiving a first write response message indicating that the information of the specific characteristic has changed in response to the first write request message from the second terminal,
The partial data stored in the specific characteristic is changed to the next partial data.
The method of claim 2,
The first write request message includes at least one of an operation code instructing to change the partial data stored in the specific characteristic to the next partial data or counter information indicating information to be changed.
The method of claim 1,
The specific characteristic includes counter information indicating the partial data included in the specific characteristic or number information indicating the number of the plurality of data divided by the specific information.
delete delete The method of claim 1,
When a collision occurs in the specific channel, the method further comprising performing a collision resolution procedure with the second terminal.
The method of claim 7, wherein performing the conflict resolution procedure,
Changing a channel when the measured energy level is greater than or equal to a threshold value;
Transmitting a trigger packet to a second terminal in the changed channel; And
The method further comprising receiving a beacon signal in the changed channel from the second terminal.
The method of claim 8,
Transmitting a request message for requesting a connection to the second terminal through Bluetooth to the second terminal through the changed channel;
Receiving a confirm message from the second terminal in response to the request message through the changed channel; And
Including the step of changing the state to a semi-connected state (Semi-Connected State) for short data transmission,
The first terminal stores the specific information in the semi-connected state.

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