KR101481150B1 - Device determination method for device to device communications - Google Patents

Abstract

The present invention relates to a method for direct communication between devices, comprising the steps of: searching for a terminal to be communicated or using a previously stored terminal information to select a terminal to be communicated, selecting a terminal to communicate with using the previously stored terminal information Determining whether there is a candidate terminal in the pre-stored terminal information, if the candidate terminal exists, determining a terminal to communicate among the candidate terminals using the pre-stored terminal information, The method comprising: transmitting a request message; establishing security between terminals when receiving an invitation response message from a terminal that has transmitted the invitation request message; and performing communication with the secured terminal, It is possible to reduce the time and power consumption of the terminal search that occurs every time the communication is attempted.

Description

[0001] The present invention relates to a method for determining a terminal to communicate in a direct communication between devices,

The present invention relates to a method for determining a terminal communicating in direct communication between devices, and more particularly, to a method for determining a terminal having a high priority by using a previously stored terminal information, .

Machine to machine (M2M) can collect necessary information through sensors attached to an object and enable mutual sharing of information between objects through a communication device attached to the object. In other words, the concept and technology that objects construct a network using a small communication device and share collected information is called M2M communication.

 M2M communication is possible with low-cost, low-power, wireless short-range data transmission using short-range wireless technology such as Zigbee, bluetooth, and Wi-Fi Direct.

In the case of direct communication between devices using short-range wireless technology such as Zigbee, bluetooth, Wi-Fi Direct, etc., it is important to determine a terminal to communicate directly by searching for a terminal capable of communication among surrounding communication terminals. In case of conventional Wi-Fi Direct or bluetooth terminal, when searching for direct communication, the terminal is searched.

In the case where a channel to be transmitted and a channel to be received are different from each other in the searching process of the two terminals, or if the request probe is not received due to a time difference in the same channel, the two terminals fail to search each other, There is a problem of consuming.

Whenever an M2M terminal belonging to the same group attempts to perform data transmission, searching for the terminal in the above manner may be very inefficient in terms of search time consumption and power consumption of the terminal for searching.

The first problem to be solved by the present invention is to provide an apparatus-to-apparatus direct communication method capable of solving a delay in search time or a terminal search failure and efficiently using power and time of a terminal consumed in searching for a terminal.

A second problem to be solved by the present invention is to provide a terminal capable of effectively solving time delay or terminal search failure and efficiently using power and time of a terminal consumed in searching for a terminal.

It is another object of the present invention to provide a computer-readable recording medium storing a program for causing a computer to execute the above-described method.

In order to accomplish the first object of the present invention, there is provided a method for controlling a mobile communication terminal, the method comprising the steps of: searching for a terminal to be communicated or using a previously stored terminal information; Determining whether there is a candidate terminal in the pre-stored terminal information if it is determined to select a terminal to be communicated using the pre-stored terminal information; If the candidate terminal exists, determining a terminal to communicate among the candidate terminals using the previously stored terminal information; Transmitting an invitation request message to the determined terminal; Setting an inter-terminal security when receiving an invite response message from a terminal that has transmitted the invite request message; And performing a communication with the security-enhanced terminal.

According to the embodiment of the present invention, when it is determined to search for the terminal to communicate in the step of determining whether to select the terminal using the terminal information to be communicated or the terminal information to be communicated, Thereby searching for a terminal capable of communication; Determining whether the discovered terminal is a terminal that has previously communicated if the terminal search is successful; And determining the searched terminal as a terminal to communicate with when the searched terminal has previously communicated, the method comprising the steps of transmitting the invitation request message, establishing the inter-terminal security, and And performing the step of performing the communication.

According to an embodiment of the present invention, the method further includes a step of determining a group owner between terminals when the searched terminal is not a terminal that has previously communicated, and when the group owner is determined, Wherein the step of determining the group owner among the terminals determines the terminal supporting the Wi-Fi direct as the group owner, It may be a direct communication method between devices.

According to an embodiment of the present invention, the step of determining a terminal to communicate among the candidate terminals comprises: classifying terminals capable of communicating among the candidate terminals; And determining a terminal to be communicated according to the priority by assigning a priority to the candidate terminal classified as the communicatable terminal by using the position or signal strength of the terminal, The priorities may be given in order of priority to the terminals in descending order or in a descending order of the strength of the signals. , The candidate terminal that received the ACK signal for retransmission of the signal is classified as the communicatable terminal or the position information of the terminal included in the peer to peer information-element (P2P IE) of the candidate terminal and the position information of the terminal And classifying the terminal into the communicatable terminal by using the strength.

According to an embodiment of the present invention, before transmitting the invitation request message, the method further comprises transmitting a request for transmission (RTS) to the candidate terminal to communicate with the terminal, And transmits the invitation request message when a CTS (clear to send) is received from the determined candidate terminal. The method of claim 1, further comprising: Wherein the step of determining whether to select the terminal determines to search for a terminal to be communicated if it is an initial communication without the previously stored terminal information or a period set to search for a new terminal, The security setting step sets security between the terminals through WPS (Wi-Fi Protected Setup). New methods can be.

According to another aspect of the present invention, there is provided an information processing apparatus including a storage unit storing terminal information; Determines whether to select a terminal to be communicated using the terminal information stored in the storage unit, assigns a priority to the candidate terminal classified as a communicable terminal by using the position of the terminal or the strength of the signal A controller for determining a terminal to communicate according to the priority; And a communication unit for transmitting and receiving the terminal information and the signal to and from the communicatable terminals, wherein the control unit classifies the candidate terminal that has received the ACK signal for retransmission of the signal as the communicable terminal, And classifies the terminal into the communicatable terminals by using the position information of the terminal and the strength of the received signal included in the Peer-to-Peer Information-Element (IE).

According to another aspect of the present invention, there is provided a computer-readable recording medium having recorded thereon a program for causing a computer to perform the direct communication method between the devices.

According to the present invention, by determining a terminal to communicate in direct communication between the devices, it is possible to reduce the time and power consumption of the terminal search that occurs every time the terminal attempts to communicate. In addition, according to the present invention, by transmitting data to the terminal located at the farthest position among terminals capable of communicating with each other with the positional information of the terminals, it is possible to reduce the number of nodes to terminals desired to communicate. .

1 is a block diagram of a terminal according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating a Wi-Fi direct communication procedure and a terminal search according to another embodiment of the present invention.
FIG. 3 illustrates a P2P IE frame according to another embodiment of the present invention.
4 is a flowchart of a direct communication method between devices according to an embodiment of the present invention.
5 is a flowchart of a method of searching for a terminal to communicate in a direct communication method between devices according to another embodiment of the present invention.
6 is a flowchart of a method of searching for a terminal to communicate in a direct communication method between devices according to another embodiment of the present invention.
7 is a flowchart of a method of determining a terminal to communicate among a plurality of candidate terminals in a direct communication method between devices according to another embodiment of the present invention.
8 is a flowchart of a direct communication method between devices according to another embodiment of the present invention.

Prior to the description of the concrete contents of the present invention, for the sake of understanding, the outline of the solution of the problem to be solved by the present invention or the core of the technical idea is first given.

A method for direct communication between devices according to an embodiment of the present invention includes the steps of: searching for a terminal to communicate with or selecting a terminal to communicate with using previously stored terminal information, Determining whether there is a candidate terminal in the pre-stored terminal information, if the candidate terminal exists, determining a terminal to communicate among the candidate terminals using the pre-stored terminal information, Setting an inter-terminal security when receiving an invitation response message from a terminal that has transmitted the invitation request message; and performing communication with the secured terminal.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art, however, that these examples are provided to further illustrate the present invention, and the scope of the present invention is not limited thereto.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, in which: It is to be noted that components are denoted by the same reference numerals even though they are shown in different drawings, and components of different drawings can be cited when necessary in describing the drawings. In the following detailed description of the principles of operation of the preferred embodiments of the present invention, it is to be understood that the present invention is not limited to the details of the known functions and configurations, and other matters may be unnecessarily obscured, A detailed description thereof will be omitted.

1 is a block diagram of a terminal according to an embodiment of the present invention.

The terminal 100 according to an exemplary embodiment of the present invention includes a storage unit 110, a control unit 120, and a communication unit 130.

The storage unit 110 stores terminal information.

More specifically, the storage unit 110 stores the received terminal information through communication with other nearby terminals. The terminal information may include a Peer to Peer (IE) information element, a Wi-Fi Simple Configuration (WSC) IE, and the P2P IE includes a terminal ID, Listen channel, Operation Channel, . In addition to the P2P attribute information, the P2P IE may further include Device Positional information, which is the location information of the terminal, and Signal Power information, which is the strength of the received signal.

The terminal information stored in the storage unit 110 searches for a communicatable terminal, transmits / receives additional terminal information used for determination of the terminal to be communicated to the searched terminal, stores the received terminal information, ). ≪ / RTI > The terminal can search for a terminal capable of communication to perform communication and at the same time transmit / receive additional terminal information to / from the searched terminal so as to determine a terminal to communicate without searching for a terminal.

The control unit 120 determines whether to select a terminal to communicate with by using the terminal information stored in the storage unit 110, and transmits the position or signal strength of the terminal to a candidate terminal classified as a communicable terminal And determines a terminal to communicate according to the priority.

More specifically, the control unit 120 determines a terminal to communicate with by using the terminal information stored in the storage unit 110. A terminal to be communicated can be determined by selecting a terminal to be communicated using the terminal information stored in the storage unit 110 or by searching for a neighboring terminal. The control unit 120 classifies the candidate terminal that received the ACK signal for retransmission of the signal into the communicable terminal or transmits the location information of the terminal included in the peer to peer information-element (P2P IE) And classifies the terminal into the communicatable terminal using the strength of the terminal.

First, the terminal to be communicated can be selected by using the terminal information stored in the storage unit 110. It is not necessary to search all the terminals every time communication is performed by determining terminals to be communicated by using the information of the terminal that already knows the information in advance and it is not necessary to transmit and receive new information for communication, Power consumption can be reduced. When it is determined to select a terminal to be communicated using the terminal information stored in the storage unit 110, it is determined whether there is a candidate terminal in the terminal information stored in the storage unit 110. If there is the candidate terminal, the terminal to communicate among the candidate terminals is determined using the previously stored terminal information. If there is no candidate terminal, the terminal to be communicated is determined through terminal search rather than terminal information stored in the storage unit 110.

Classifying a terminal capable of communicating among the candidate terminals to determine a terminal to be communicated among the candidate terminals, and when the number of candidate terminals classified as the communicable terminal is plural, And determine a terminal to communicate according to the priority. If there is one candidate terminal, the candidate terminal can be determined as the terminal to be communicated. However, when there are a plurality of candidate terminals, a candidate terminal having a higher priority among the candidate terminals is determined as the terminal to be communicated. The priorities may be given in order of closest to the locations of the terminals, or may be given priority in descending order of strength of the signals.

 In order to classify the candidate terminals as communicatable terminals, two methods can be used. Classifies the candidate terminal that received the ACK signal for retransmission of the signal into the communicatable terminal or uses the position information of the terminal and the strength of the received signal included in the peer to peer information-element (P2P IE) of the candidate terminal And classify it as the communicatable terminal.

First, terminals capable of communicating can be classified using a communication process. An acknowledgment or a non-acknowledgment (Nack) signal is received from a terminal that has received the data after transmitting data for retransmission of the data in the communication between wireless terminals. If the Ack is received during data transmission / reception and the terminal is installed in a fixed location, the channel environment or the distance will be the same, so the terminal receiving the Ack signal can determine that communication is possible. It is possible to store the ID of the terminal determined to be communicable in the storage unit 110 together with the received signal strength, and classify it as a communicatable terminal. If the candidate terminal receiving the Ack signal is one, the candidate terminal can be determined as a terminal to communicate with. If there are a plurality of candidate terminals to which the ACK signal has been transmitted, the candidate terminals having the highest ACK signal strength may be given priority and determined to be the terminal to be communicated.

Next, it can be classified into the communicatable terminals by using the position information of the terminal and the strength of the received signal included in the peer to peer information-element (P2P IE). It is judged that the terminal can communicate by using the distance of the terminal and the received signal strength of the signal by using the Device Positional information and the Signal Power information transmitted from the P2P attribute information of the P2P IE and classifies it as a communication capable terminal. When the distance of the terminal is within a critical distance or the received signal strength of the signal is equal to or greater than a threshold value, the terminal can be classified as a communicatable terminal. When determining a terminal to be communicated using the distance of the terminal, priority is given to a candidate terminal farthest from the terminal in order to reduce the number of nodes, or a candidate terminal having the shortest distance from the terminal Can be given priority. When a candidate terminal is classified by the strength of a received signal, priority can be given to a candidate terminal having the highest received power.

The base station sets security between the terminals when the terminal transmits the invite request message to the determined terminal after determining the terminal to be communicated and receives the invite response message from the terminal that has transmitted the invite request message, .

(RTS, request to send) to the determined candidate terminal before transmitting the invitation request message, and transmits a terminal to be communicated from the determined candidate terminal (CTS, clear to send) to the determined candidate terminal And to transmit the invitation request message when it is received. A request to send (RTS) message is transmitted to a terminal classified as a communicatable terminal, and an invitation request message is received after receiving a CTS (clear to send) message. Even if the invite request message is not received due to the channel status of the terminal receiving the invite request message or communication with another terminal during transmission of the invite request message, The mobile station can transmit the unnecessary invite request message by transmitting and receiving the transmission request and the transmittable message in case that there is no terminal receiving the invite request message. After transmitting the transmission request message, if there is no terminal transmitting a transmittable message among the terminals capable of communicating, the terminal starts the search process again.

The inter-terminal security can be set through WPS (Wi-Fi Protected Setup). WPS was proposed by the Wi-Fi Alliance as a standard for the secure installation of wireless networks. WPS simplifies the network connection process between terminals and protects the network from external attacks. A terminal can generate a service search request frame and a service search response frame using a WPS IE (Information Element), and can determine service information supported by the terminal through the frame.

If the control unit 120 determines to search for a terminal to be communicated, the control unit 120 searches for a terminal capable of communicating by transmitting and receiving a probe, and if the terminal search is successful, And if the searched terminal has previously communicated with the terminal, it can determine the searched terminal as a terminal to communicate with. When the terminal to be communicated is determined, an invitation request message is transmitted, and communication is established after establishing security between the terminals.

When it is determined to search for a terminal to be communicated, a terminal searching process is performed to determine a terminal to communicate with. The terminal search process will be described in detail with reference to FIG. FIG. 2A shows a process of searching for a terminal of Wi-Fi direct. The terminal 1 (device 1) 210 and the terminal 2 (device 2) 220 search for a peripheral terminal in need of data transmission. The number of channels used for the search of the UE is three, and channels 1,6,11 (2412, 2437, and 2462 MHz) are set to be used, and the UE can search through three channels in a search or listen state It can receive or transmit probes. The two terminals 210 and 220 transmit the request probe through channels 1, 6 and 11. However, since both terminals transmit probes in the search state, they can not hear each other's requests. Then, the terminal 1 alternates channels on the channels 1, 6 and 11, and the peripheral terminal waits for the reception of the request probe in the listening state. In the case of the terminal 2 (220), only the channel 6 receives the request probe of the terminal in the listening state, and then transmits the request probe through the channels 1, 6 and 11 immediately. The terminal 1 210, which is in a listening state in the listen state on the channels 1, 6 and 11, returns to the search state and transmits a request probe on each channel. At this time, the terminal 2 (220) receives the request probe of the terminal 1 (210) on channel 6 and transmits a response probe, so that the two terminals succeed in searching each other. In the case of searching for a terminal to communicate, when the channel to be transmitted and the channel to be received are different from each other in the searching process of the two terminals or when the request probe is not received due to the time difference in the same channel as shown in FIG. And it is possible to consume power and time by continuously transmitting the probes. Whenever an M2M terminal belonging to the same group attempts to perform data transmission, searching for the terminal in the above manner may be very inefficient in terms of search time consumption and power consumption of the terminal for searching. Therefore, when the previously stored terminal information can not be used, it is effective to perform terminal search.

2B is a flowchart illustrating a process of searching for a Wi-Fi direct terminal. In step 230, when the terminal requires communication, the terminal starts searching for the terminal. First, all the channels of the IEEE 802.11 are scanned to search for surrounding P2P (Pear- to Pear) group and IEEE 802.11 infrastructure network. In step 240, if there is no P2P (Peer-to-Pear) group and IEEE 802.11 infrastructure network available in the vicinity, a probe request is transmitted to an arbitrary channel for communication through other terminals in the vicinity. At this time, transmitting the probe request from the fixed channel is called Search state. The probe request may include information such as a Pear-to-Pear (IE) Information Element (IE) and a Wi-Fi Simple Configuration (WSC) IE. The P2P IE may include information such as ID of the terminal, Listen Channel, Operating Channel, and the like. The terminal transmitting the probe request waits on the channel to receive the probe request of the other terminal on the specific channel. This is called Listen state. The terminal transmitting the probe request receives the probe response message from the terminal receiving the prober request. In the probe response frame, an operating channel or a listener channel can be transmitted, and a probe response also includes a P2P IE and a WSC IE, and is transmitted to the UE. And the search for the terminal is terminated when the terminal receives the probe response.

In the M2M communication, it is assumed that the mobile station mainly communicates at a fixed position. Therefore, the distance between the terminals and the intensity of the signal do not change greatly. Also, when the same user uses the plurality of terminals to establish the M2M communication network by using the direct communication between the devices, all terminals can be set to the same channel for the convenience of terminal search. In such a situation, the terminal can be searched only when it is necessary to search for the terminal. The terminal can periodically search the terminal at the time of initial installation or in order to know the appearance of a new peripheral terminal.

When the requirements of the above two searches occur, the search of the terminal is started. A Probe Request message is transmitted to search for the UE. Probe Requests may include P2P IE, WSC IE. And additionally transmits a parameter for determining the terminal to the P2P IE. The parameter includes the distance information of the terminal and the channel information between the terminals.

If it is determined that the discovered terminal is a terminal that has previously communicated, if the detected terminal is a previously communicated terminal, the terminal is determined to be a terminal to communicate with, Message, and after establishing security between terminals, communication can be performed.

When the searched terminal is not a terminal that has previously communicated, the terminal determines a group owner between the terminals, and if the group owner is determined, the terminal can set security and then perform communication. A terminal supporting Wi-Fi direct may be determined as the group owner. If the searched terminal is not a terminal that has previously communicated, a group owner (GO) is set between the terminals. The group owner means a terminal that acts as an access point (AP) temporarily in Wi-Fi Direct like a wireless LAN. The determination of the group owner can be made through the GO intent information in the message through the Group Owner negotiation message after the search of the terminal is completed. The Go Intent information has a value ranging from 0 to 15, and the higher the value, the more likely it is the group owner. The group owner can only form a terminal supporting Wi-fi direct, and the existing terminal performs only the role of a client.

In determining whether to search for a terminal to be communicated or to select a terminal using terminal information stored in the storage unit 110, it is determined whether the initial communication with no terminal information stored in the storage unit 110 or the period set to search for a new terminal It is possible to search for the terminal to communicate with. In the case of the terminal performing the initial communication, since there is no information transmitted / received to / from other terminals, there is no terminal information stored in the storage unit 110, so that direct communication between the devices is possible only after the terminal searching process is inevitable. In addition, if there is movement of the terminal or entry of a new terminal, the terminal search can be performed to detect a change of the terminal. Even if there is a change in the terminal environment, efficiency can be reduced when using only the existing stored terminal information, so that the terminal can be periodically searched for every predetermined period.

The communication unit 130 transmits and receives the terminal information and signals to and from the communicatable terminals.

More specifically, the communication unit 130 transmits / receives data information or various signals to / from other terminals. A probe request for terminal search, terminal information, an invitation request message, an invitation response message, a transmission request, a transmission enable, and an ACK signal. The communication unit 130 can perform data communication in the same manner as the IEEE 802.11 standard.

FIG. 3 illustrates a P2P IE frame according to another embodiment of the present invention.

3A shows a configuration of a P2P IE format. P2P IE is defined in IEEE Std 802.11-2007, and the configuration field of P2P IE can be composed of Element ID, Length, P2P Attributes, and so on. P2P Attributes consists of one octet of P2P Attribute ID field, two octets of Length field, and variable length of attribute-specific information field. The P2P IE frame consists of up to 251 octets. If the P2P IE finds an unknown or reserved property ID value, the P2P device will ignore the statement and interpret the syntax of the remaining fields. One or more P2P IEs may be included in one frame.

FIG. 3B shows P2P Attribute ID definitions. P2P Attribute ID consists of P2P Capability, P2P Device ID, Group Owner Intent, Listen channel, P2P Device Info, etc. 19-220, 222-255 ID is reserved attribute, . P2P Device info may include P2P Device address, Config Method, Primary Device Type, Device Name and so on.

FIG. 3C shows that the P2P Attribute ID definitions indicate the use of additional information. In FIG. 3B, the attribute IDs 19-220 and 222-225 in the P2P attribute ID definitions are reserved and reserved for additional information transmission. In order to determine the terminal to be communicated, it transmits Device Positional information and Signal Power Information using the reserved Attribute IDs 19 and 20. The device position information includes the location information of the terminal, and the signal power information includes the reception power information of the terminal after passing through the channel.

4 is a flowchart of a direct communication method between devices according to an embodiment of the present invention.

In step 410, it is determined whether to search for a terminal to communicate with or to use a previously stored terminal information to select a terminal to communicate with.

More specifically, it is determined whether to search for a terminal to communicate with or use the stored terminal information to select a terminal to communicate without searching for the terminal. It may be determined to search for a terminal to be communicated if it is the initial communication without the pre-stored terminal information, or corresponds to a period set to search for a new terminal. The pre-stored terminal information may include a step of searching for a terminal capable of communicating, transmitting / receiving additional terminal information used for determination of the terminal to be communicated to the searched terminal, and storing the received terminal information . The detailed description of this step corresponds to the detailed description of the storage unit 110 and the control unit 120 of FIG. 1 and is replaced with a detailed description of the storage unit 110 and the control unit 120 of FIG.

In step 420, if it is determined to select a terminal to communicate with using the previously stored terminal information, it is determined whether there is a candidate terminal in the previously stored terminal information.

More specifically, it is determined whether there is a candidate terminal stored in the previously stored terminal information. The detailed description of this step corresponds to the detailed description of the storage unit 110 and the control unit 120 of FIG. 1 and is replaced with a detailed description of the storage unit 110 and the control unit 120 of FIG.

If there is the candidate terminal, step 430 is to determine a terminal to communicate among the candidate terminals using the pre-stored terminal information.

More specifically, if the candidate terminal exists as a result of the determination in step 420, it is determined which terminal among the candidate terminals to communicate with. If there is no candidate terminal, the terminal searching for the terminal to communicate with. This step will be described in detail in FIG. The detailed description of this step corresponds to the detailed description of the control unit 120 of FIG. 1, and is replaced with a detailed description of the control unit 120 of FIG.

Step 440 is a step of transmitting an invitation request message to the determined mobile station.

More specifically, in step 430, an invitation request message is transmitted to a terminal determined as a terminal to communicate with. Further comprising the step of transmitting a request for transmission (RTS) to the candidate terminal determined to be communicated before transmitting the invitation request message, and transmitting the request to send to the candidate terminal from the determined candidate terminal (CTS, clear to send the invitation request message. The detailed description of this step corresponds to the detailed description of the control unit 120 of FIG. 1, and is replaced with a detailed description of the control unit 120 of FIG.

Step 450 is a step of establishing security between terminals when receiving an invitation response message from the terminal that has transmitted the invitation request message.

More specifically, when receiving the invitation response message from the terminal that received the invitation request message transmitted in step 440, it sets security between terminals for security during communication. Terminal security can be established through WPS (Wi-Fi Protected Setup). The detailed description of this step corresponds to the detailed description of the control unit 120 of FIG. 1, and is replaced with a detailed description of the control unit 120 of FIG.

Step 460 is a step of performing communication with the secure terminal.

More specifically, communication with the terminal is performed when security is established with the terminal to be communicated. The detailed description of this step corresponds to the detailed description of the control unit 120 of FIG. 1, and is replaced with a detailed description of the control unit 120 of FIG.

5 is a flowchart of a method of searching for a terminal to communicate in a direct communication method between devices according to another embodiment of the present invention.

Step 510 is a step of searching for a terminal capable of communicating by transmitting and receiving a probe.

More specifically, when it is determined in step 410 that a terminal to be communicated is to be searched, terminal search is performed by transmitting and receiving a probe. The detailed description of this step corresponds to the detailed description of the storage unit 110 and the control unit 120 of FIG. 1 and is replaced with a detailed description of the storage unit 110 and the control unit 120 of FIG.

In step 520, if the terminal search is successful, it is determined whether the searched terminal has previously communicated with.

More specifically, if the terminal search in step 510 is successful, it is determined whether the searched terminal has previously communicated with, to determine whether communication can be performed using the previous information. The detailed description of this step corresponds to the detailed description of the control unit 120 of FIG. 1, and is replaced with a detailed description of the control unit 120 of FIG.

In step 530, when the searched terminal has previously communicated, it is determined that the searched terminal is a terminal to communicate with.

More specifically, if it is determined in step 520 that the discovered terminal has previously communicated with the terminal, communication can be performed using the existing information, and the terminal searching for the discovered terminal can be determined do. The detailed description of this step corresponds to the detailed description of the control unit 120 of FIG. 1, and is replaced with a detailed description of the control unit 120 of FIG.

If it is determined in step 530 that a terminal to communicate with is determined, steps 440 through 460 are performed, that is, the invitation request message is transmitted, the inter-terminal security is established, and the communication is performed.

6 is a flowchart of a method of searching for a terminal to communicate in a direct communication method between devices according to another embodiment of the present invention.

Step 610 is a step of determining a group owner between terminals when the discovered terminal is not a terminal that has previously communicated.

More specifically, if it is determined in step 520 that the discovered terminal is not a terminal that has previously communicated, a group owner between terminals is determined for communication. A terminal supporting Wi-Fi direct may be determined as the group owner. The detailed description of this step corresponds to the detailed description of the control unit 120 of FIG. 1, and is replaced with a detailed description of the control unit 120 of FIG.

If the group owner is determined, establishing the inter-terminal security without transmitting the invitation request message and performing the communication.

7 is a flowchart of a method of determining a terminal to communicate among a plurality of candidate terminals in a direct communication method between devices according to another embodiment of the present invention.

Step 710 is a step of classifying the terminals available for communication among the candidate terminals.

More specifically, if it is determined in step 420 that there are a plurality of candidate terminals, all candidate terminals may not be capable of communicating with each other. Classifies the candidate terminal that received the ACK signal for retransmission of the signal into the communicatable terminal or uses the position information of the terminal and the strength of the received signal included in the peer to peer information-element (P2P IE) of the candidate terminal And classify it as the communicatable terminal. The detailed description of this step corresponds to the detailed description of the control unit 120 of FIG. 1, and is replaced with a detailed description of the control unit 120 of FIG.

In step 720, when there are a plurality of candidate terminals classified as the communicatable terminals, priority is given to them using the position or signal strength of the terminals, and the terminals to communicate are determined according to the priority.

More specifically, as a result of the classification in step 710, when there are a plurality of candidate terminals classified as the communicatable terminals, priority is given to them using the position or signal strength of the terminals to determine the terminals to communicate with. And determines a terminal to communicate according to the priority. The priorities may be given in order of closest to the locations of the terminals, or may be given priority in descending order of strength of the signals. The detailed description of this step corresponds to the detailed description of the control unit 120 of FIG. 1, and is replaced with a detailed description of the control unit 120 of FIG.

8 is a flowchart of a direct communication method between devices according to another embodiment of the present invention.

It is determined in step 810 whether a terminal search is necessary. If it is determined in step 810 that the terminal search is not required, it is determined in step 822 whether a candidate terminal exists. If it is determined in step 288 that a candidate terminal exists, the candidate terminal is classified as a terminal capable of communicating using P2P attribute information or ACK (Acknowledgment) to determine a terminal to communicate with. In step 842, the handover request message is transmitted to the terminal determined as a terminal to be communicated by handshaking before transmitting the invitation request message. When the signal transmission request is completed through handshaking, the invite request message is transmitted in step 842. Upon receipt of the invitation response message, security is established between the terminals using the WPS in step 850, and communication is performed in step 860.

If it is determined in step 810 that the terminal search is required, the terminal search is performed in step 821. If the terminal search in step 821 is successful, it is determined whether the terminal discovered in step 830 has previously communicated. If it is determined in step 830 that the discovered terminal is a terminal that has previously communicated, the base station transmits an invite request message in step 842, establishes security in step 850, and performs communication in step 860.

If it is determined in step 830 that the discovered terminal is not a terminal that has previously communicated with, it determines a group owner (GO) in step 841, and sets security in step 850 when the group owner is determined. do.

If it is determined in step 822 that the candidate terminal does not exist, the terminal search in step 821 is performed.

When the terminal for the M2M communication is installed for the first time, searching for terminals belonging to the existing group is started. Alternatively, the order of transmission terminals can be changed by periodically searching for a terminal and searching for installed terminals or updating terminal information. The search for the terminal is performed in step 821. The number of terminals to be searched according to the base of the existing M2M terminal may be a large number or a small number.

It is possible to simplify the procedure of the terminal search performed every time data is transmitted by the M2M terminals belonging to the same group using the pre-stored terminal information, and to control the communication terminal according to the ranking, thereby enabling data transmission through the minimum node in communication. In addition, the period of terminal search can be set by the manager managing the M2M terminal group.

Embodiments of the present invention may be implemented in the form of program instructions that can be executed on various computer means and recorded on a computer readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

As described above, the present invention has been described with reference to particular embodiments, such as specific elements, and specific embodiments and drawings. However, it should be understood that the present invention is not limited to the above- And various modifications and changes may be made thereto by those skilled in the art to which the present invention pertains.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

100: terminal
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210: terminal 1
220: Terminal 2

Claims (14)

Determining whether to select a terminal to communicate with by using the terminal information to be communicated or previously stored terminal information;
Determining whether there is a candidate terminal in the pre-stored terminal information if it is determined to select a terminal to be communicated using the pre-stored terminal information;
If the candidate terminal exists, determining a terminal to communicate among the candidate terminals using the position or signal strength of the terminal among the previously stored terminal information;
Transmitting an invitation request message to the determined terminal;
Setting an inter-terminal security when receiving an invite response message from a terminal that has transmitted the invite request message; And
And performing communication with the secure terminal. The method according to claim 1,
When it is determined to search the terminal to communicate in the step of determining whether to select the terminal using the terminal information or the previously stored terminal information,
Searching for a terminal capable of communication by transmitting and receiving a probe;
Determining whether the discovered terminal is a terminal that has previously communicated if the terminal search is successful; And
And determining the searched terminal as a terminal to be communicated if the searched terminal is a terminal that has previously communicated,
The method comprising: transmitting the invitation request message; establishing the inter-terminal security; and performing the communication. 3. The method of claim 2,
Further comprising the step of determining a group owner between terminals when the searched terminal is not a terminal that has previously communicated,
And if the group owner is determined, performing the step of setting the inter-terminal security and performing the communication. The method of claim 3,
Wherein the step of determining a group owner between the terminals comprises:
And a terminal supporting Wi-Fi direct is determined as the group owner. The method according to claim 1,
If there is no candidate terminal in the step of determining whether there is a candidate terminal in the previously stored terminal information,
And searching for a terminal to be communicated. The method according to claim 1,
Wherein the step of determining a terminal to communicate among the candidate terminals comprises:
Classifying the terminals capable of communicating among the candidate terminals; And
Determining a terminal to communicate according to the priority by assigning a priority to the candidate terminal using the position or signal strength of the terminal when the number of candidate terminals classified as the communicatable terminal is plural, . The method according to claim 6,
Wherein the step of classifying the terminals capable of communicating among the candidate terminals comprises:
Classifies the candidate terminal that received the ACK signal for retransmission of the signal into the communicatable terminal or uses the position information of the terminal and the strength of the received signal included in the peer to peer information-element (P2P IE) of the candidate terminal And classifying the terminal into the communicatable terminal. The method according to claim 6,
The priority order may be,
Wherein the priorities are given in order of the closest position of the terminals or the priority is assigned in descending order of the intensity of the signals. The method according to claim 1,
The pre-
Searching for a terminal capable of communication;
Transmitting / receiving additional terminal information used for the determination of the terminal to be communicated to the searched terminal; And
And storing the received terminal information in the step of storing the received terminal information. The method according to claim 1,
Before sending the invitation request message,
Further comprising the step of transmitting a request for transmission (RTS, request to send) to the candidate terminal determined to be communicating with the terminal,
Wherein the invite request message is transmitted when the terminal to be communicated is received from a determined candidate terminal (CTS, clear to send). The method according to claim 1,
Wherein the step of searching for a terminal to be communicated or determining whether to select a terminal using previously stored terminal information comprises:
Determining whether to search for a terminal to be communicated if it is an initial communication without the pre-stored terminal information or a period set to search for a new terminal. The method according to claim 1,
The step of establishing the inter-
And establishing the inter-terminal security through Wi-Fi Protected Setup (WPS). A computer-readable recording medium storing a program for causing a computer to execute the method according to any one of claims 1 to 12. A storage unit for storing terminal information;
Determines whether to select a terminal to be communicated using the terminal information stored in the storage unit, assigns a priority to the candidate terminal classified as a communicable terminal by using the position of the terminal or the strength of the signal A controller for determining a terminal to communicate according to the priority; And
And a communication unit for transmitting and receiving the terminal information and the signal with the communicatable terminals,
Wherein,
Classifying the candidate terminal that received the ACK signal for retransmission of the signal into the communicatable terminal or using the strength of the received signal and the location information of the terminal included in the peer to peer information-element (P2P IE) of the candidate terminal And classifies the communication terminal into the communicatable terminal.

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