KR102011666B1 - D-to-D system using 5G small cell, and the method therefor - Google Patents

Abstract

The present invention relates to D-to-D communication using a 5G small cell, wherein a user terminal (UE) located in the service area of the small cell uses the 5G communication method as it is and the terminal to be called is located in the service area of the small cell. If a D to D connection is provided, and the terminal to be called is not located in the service area of the small cell, the 5G communication network is used by accessing the DAS, and the calling terminal for the D to D connection from the UE It provides a D-to-D system and a method using a 5G small cell that provides a D to D connection between any terminal and the terminal located in the same 5G small cell without searching.

Description

D-to-D system and method using 5G small cell {D-to-D system using 5G small cell, and the method therefor}

The present invention relates to D-to-D communication using a 5G small cell, wherein a user terminal (UE) located in the service area of the small cell uses the 5G communication method as it is and the terminal to be called is located in the service area of the small cell. If a D to D connection is provided, and the terminal to be called is not located in the service area of the small cell, the 5G communication network is used by accessing the DAS, and the calling terminal for the D to D connection from the UE It relates to a D-to-D system and a method using a 5G small cell that provides a D to D connection between any terminal and the terminal located in the same 5G small cell without searching.

Device-to-device (D to D) communication refers to a method in which a terminal directly communicates with another terminal. For example, when D to D communication is performed between the first terminal and the second terminal, the first terminal may generate a message including data to be transmitted to the second terminal, and transmit the generated message to the second terminal. You can send it directly. The second terminal may receive a message including data from the first terminal, and may obtain data included in the received message.

D2D (DEVICE-TO-DEVICE) signal transmission method performed by the terminal in the wireless communication system of the Republic of Korea Patent No. 10-1921989 B1 shown in FIG. There is a terminal technology using the method. This technology relates to a device-to-device (D2D) signal transmission method performed by a terminal in a wireless communication system and a terminal using the method, and the method includes information indicating whether mode 2 operation is allowed in an exceptional state. And upon determining whether the terminal is in the exceptional state, and performing the mode 2 operation when the terminal is in the exceptional state, the mode 2 operation selects a specific resource from a resource pool and selects the selected resource. It is characterized in that the operation for transmitting the D2D signal by using.

As another background technology for the present invention, there is a signaling technique for D2D discovery between cells in the LTE network of Korea Patent Publication No. 10-2018-0036804 A shown in FIG. 2. This technique relates to a method of signaling for enhanced Node B (eNB), user equipment (UE), and proximity service and D2D discovery in an LTE network, wherein the eNB includes D2D resources configured by one or more neighbor cells. Inter-cell D2D discovery may be supported by transmitting signaling to the first user equipment (UE) to indicate configuration information for the D2D discovery resource pool, wherein the configuration information is provided between the serving cell of the first UE and one or more neighboring cells. And to include a timing offset.

Another background art of the present invention is a method and apparatus for transmitting D2D synchronization signals of Korean Patent No. 10-1905372 B1 shown in FIG. 3. This technique relates to a method, an apparatus, a network node, and a computer program product for transmitting D2D synchronization signals, wherein D2D synchronization signals are received from a first network node, and the hop number of the D2D synchronization signals is a radio of the D2D synchronization signals. Is determined based on the resources, and is configured to determine based on the number of hops whether to transmit the D2D synchronization signals to the second network node.

KR 10-1921989 B1 KR 10-2018-0036804 A KR 10-1905372 B1 KR 10-1698858 B1 KR 10-1794689 B1

 5G; NR; User Equipment (UE) radio transmission and reception; Part 1: Range 1 Standalone (3GPP TS 38101-1 version 1530 Release 15), ETSI TS 138 101-1 V1530 (2018-10)  5G; Study on new radio access technology (3GPP TR 38912 version 1410 Release 14), ETSI TR 138 912 V1410 (2017-10)  5G; NR; Overall description; Stage-2 (3GPP TS 38300 version 1531 Release 15), ETSI TS 138 300 V1531 (2018-10)

According to the present invention, a user terminal (UE) located in a service area of a small cell uses a 5G communication method as it is, and provides a D to D connection when the terminal to be called is located in a service area of a small cell. Provided are a D to D system using a 5G small cell and a method thereof, in which a 5G communication network is used by connecting to a DAS when not located in the service area of the small cell. The D to D system and the method using the 5G small cell of the present invention, D to D connection between any terminal and the terminal located in the same 5G small cell without the search of the calling terminal for the D to D connection in the user terminal (UE) It is an object of the present invention to provide a D-to-D system using the 5G small cell and a method thereof.

The present invention, in order to solve the above problems, a small cell having at least one small cell AP, a backhaul network and the mobile communication via the small cell AP via a Distributed Antenna Systems (DAS) In a D-to-D system using a 5G small cell connected to a macro cell base station or a core network through a mobile switching center (MSC), D to D communication between the small cell AP and a distributed antenna system (DAS) And a control unit, wherein the D to D communication control unit collects user terminal and access small cell AP information in the small cell and receives information of a terminal called from a user terminal (UE) located in the small cell. When the called terminal is located in the small cell, if the user terminal (UE) and the call to the terminal (D) D to D connection is performed, the called terminal is not located in the small cell In the present invention, a D-to-D system using a 5G small cell, which is configured to perform 5G communication by connecting the UE to a distributed antenna system (DAS), provides a means for solving the problem.

According to the D-to-D system and the method using the 5G small cell of the present invention, the user terminal (UE) located in the service area of the small cell uses the 5G communication method as it is and the terminal to be called is the service area of the small cell If it is located inside, it provides D to D access. If the terminal to be called is not located in the service area of the small cell, it connects to the DAS to use 5G communication network. There is a technical effect of providing a D to D connection between any terminal and the terminal located in the same 5G small cell without searching the calling terminal.

1 is a background technology of the present invention, a method of transmitting a D2D (DEVICE-TO-DEVICE) signal performed by a terminal in a wireless communication system and the configuration of a terminal technology using the method
2 is a diagram showing the configuration of a signaling technique for D2D discovery between cells in an LTE network as another background technology for the present invention.
3 is a schematic diagram of a method and apparatus for transmitting D2D synchronization signals as another background technology of the present invention.
4 is a configuration of small cells of a 5G mobile communication system
5 is a diagram illustrating a connection relationship between small cells in a 5G mobile communication system.
6 is a basic configuration of a D-to-D system using a 5G small cell of the present invention
7 is a configuration of a small cell AP 100 in the D-to-D system using the 5G small cell of the present invention
8 is a configuration of the D to D communication control unit 200 in the D-to-D system using the 5G small cell of the present invention
9 is a driving method for performing a D to D connection when a user terminal (UE) in a small cell calls another user terminal located in the same small cell;
10 is a driving method for performing an external 5G connection when a user terminal (UE) in a small cell calls another user terminal not located in the same small cell;

The following merely illustrates the principles of the invention. Accordingly, those of ordinary skill in the art may implement the principles of the present invention and invent various devices included in the concept and scope of the present invention, although not clearly described or illustrated herein. Furthermore, all conditional terms and embodiments listed herein are in principle clearly intended for the purpose of understanding the concept of the invention and are not to be limited to the specifically listed embodiments and states. Should be. In addition, it is to be understood that all detailed descriptions, including the principles, aspects, and embodiments of the present invention, as well as listing specific embodiments, are intended to include structural and functional equivalents of these matters.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. In the following description of the present invention, if it is determined that the detailed description in the related known art may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fifth generation mobile communication (5G) is a next generation wireless network technology including mobile communication, which uses a very high frequency millimeter wave. Although a clear configuration has not yet been established, 3GPP Release 15 is the most common definition of 5G. Unlike the carrier frequencies of 3G or 4G, millimeter waves used to implement broadband in 5G networks can collide and disperse when there is a failure due to straightness. Therefore, millimeter waves (30GHz-300GHz) used in 5G communication can transmit only a short distance due to their frequency characteristics. In addition, there is a technical problem of millimeter wave with strong straightness due to radio wave blocking by weather or physical feature. To overcome this problem, the proposed 5G standard design method uses small cells over a short range (about 250-300m) and uses a large number of small cells for communication rather than a small number of large cells.

4 illustrates a configuration of small cells of a 5G mobile communication system. The 5G small cells are divided into femto cells, pico cells, micro cells, and the like according to the radius of the serviced cell, its output, and the number of user equipment (UE). The service area in which the millimeter wave can be reached straight is accessible by a 5G macro cell. Small cells of a 5G mobile communication system may be constructed in a public small cell for access service of unspecified user equipment (UE) in a public place, and small cells for providing data access in a building or a house. Each small cell may be configured around an access point (AP) device as a small base station. Each of the small cells may be connected to a 5G macrocell via a wireless backhaul network via a microwave or millimeter wave channel to a core network or directly to a core network via a large fiber channel backhaul. In a 5G communication system, a user terminal (UE) may receive a network service via a small cell or directly connected to a 5G macrocell.

5 illustrates a connection relationship between small cells in a 5G mobile communication system.

Each small cell access point device (hereinafter, referred to as a 'small cell AP') constituting a small cell in 5G communication is provided through a backhaul network via a Distributed Antenna Systems (DAS) such as massive MIMO. It is connected to a macrocell base station or core network, and the macrocell base station or core network is connected to each of the small cell APs via mobile switching centers (MSCs). Accordingly, the access request of the user equipments (UEs) may be provided with a 5G mobile communication service by being connected to a macrocell base station or a core network via a distributed antenna system-backhaul network-mobile communication switching center.

In the configuration of the 5G small cell as described above, when data transmission or reception is performed between at least one UE located in the same cell, the access point device of the small cell is connected to the DAS-backhaul network-MSC-macrocell (core network). Since the data is exchanged within the same small cell, the DAS performs direct communication from the DAS to the core network, thereby reducing data traffic volume, delay speed, and delay. In particular, as the demand for multimedia and social network services has exploded, the amount of mobile traffic is increasing, and the number of things is continuously increasing due to the appearance of the Internet of Things (IoT). Accordingly, traffic volume is expected to increase even more explosively.

Background of the Invention A direct communication between devices (device to device, D to D) has been proposed. The above-described D to D communication has been discussed since 4G communication in LTE (long term evolution) scheme, and a technology for searching and accessing a terminal to be accessed by a user terminal in a periphery is common. However, this conventional method has been a barrier to practical use because not only a user terminal capable of D to D communication is provided separately, but also a communication channel different from the base station must be secured through the base station for D to D communication.

The present invention is to solve the above problems, the user terminal (UE) located in the service area of the small cell uses the 5G communication method as it is and the terminal to be called is located in the service area of the small cell D to D When the terminal to be called is not located within the service area of the small cell, the present invention provides a D to D system using a 5G small cell and a method for connecting to a DAS to use a 5G communication network. The D to D system and the method using the 5G small cell of the present invention, D to D connection between any terminal and the terminal located in the same 5G small cell without the search of the calling terminal for the D to D connection in the user terminal (UE) To provide.

Figure 6 shows the basic configuration of a D-to-D system using a 5G small cell of the present invention. D-to-D system using the 5G small cell of the present invention, the small cell having at least one small cell AP (100) and the small cell AP via a distributed antenna system (DAS: Distributed Antenna Systems) In a D-to-D system using a 5G small cell connected to a macro cell base station or a core network through a backhaul network and mobile switching centers (MSCs), it is distributed with the small cell AP 100. The D to D communication control unit 200 is provided between the antenna systems (DAS), and the D to D communication control unit 200 collects user terminal and access small cell AP information in the small cell and is located in the small cell. When the information on the terminal called from the user terminal (UE) is received, if the called terminal is located in the small cell, and performs the D to D connection between the UE and the terminal called (call), The called terminal is in a small cell If not located in the user terminal (UE) is characterized in that configured to perform 5G communication by connecting to a distributed antenna system (DAS).

Figure 7 shows the configuration of a small cell AP 100 in a D-to-D system using a 5G small cell of the present invention.

Small cell AP 100 of the present invention;

A main CPU 110 controlling the small cell AP 100; UE for storing the ID of each small cell AP 100 and the information (for example, CID: caller ID) of the user terminal (UE) connected to the small cell AP 100 according to the small cell AP 100. Data memory 120; A nonvolatile memory 130 in which a program and data for driving the main CPU 110 and an ID of each of the small cell APs 100 are stored; A UE data processor 150 for detecting signal strength of a user terminal (UE) and detecting a data traffic amount; An uplink interface 160 for packet communication with the D to D communication control unit 200 under control of the main CPU 110; A downlink interface 170 for packet communication with user terminals (UEs) under the control of the main CPU 110; A packet synchronization clock 140 for synchronously communicating the uplink packets with the downlink packets; It consists of.

8 illustrates a configuration of the D to D communication control unit 200 in the D-to-D system using the 5G small cell of the present invention. The D to D communication control unit 200 of the present invention;

A D to D communication processor 210 for driving the D to D communication control unit 200; An AP uplink communication unit 220 connected to the D to D communication processor 210 to receive uplink packets of the small cell APs 100; An AP downlink communication unit 230 connected to the D to D communication processor 210 to provide downlink packets for the small cell APs 100; A packet buffer for temporarily storing the uplink packets and the downlink packets; An AP ID memory 250 for storing IDs of small cell APs 100 controlled by the D to D communication control unit 200; A packet clock 260 for communicating the uplink packets and the downlink packets with small cell APs 100 in synchronization with a macro cell and a core network; A packet converter 270 for rearranging uplink packets stored in the packet buffer 240 into downlink packets or converting downlink packets into uplink packets; The D to D communication processor 210 connects the uplink packets and the downlink packets to a distributed antenna system (DAS) and provides or provides the macrocell and the core network through a backhaul network and a mobile communication switching center (MSC). Receiving DAS interface 280; And a UE / AP map memory 290 for storing information of a user terminal (UE) connected for each ID of the small cell APs 100 controlled by the D to D communication control unit 200.

The D to D communication control unit 200 of the present invention provides uplink packets of the small cell APs 100 to the macro cell and the core network through the DAS interface 280 by the D to D communication processor 210 and to the DAS interface. The downlink packet may be provided from the macro cell and the core network through 280, and the uplink packets received from the small cell APs 100 through the AP uplink communication unit 220 may be converted into a packet converter. 270 may be converted into a downlink packet and provided to the small cell APs 100 through the AP downlink communication unit 230.

FIG. 9 illustrates a method of driving a D-to-D system using a 5G small cell of the present invention, in which a D to D connection is performed when a user terminal (UE) in a small cell calls another user terminal located in the same small cell. The driving method is shown. The driving method will be described step by step as follows.

S100: transmitting a request signal for calling another user terminal from a user terminal UE located in the small cell;

S105: the small cell AP to which the user terminal (UE) which has sent the request signal is connected (uplink) transmitting an ID and other user terminal data called to the D2D communication control unit 200;

S110: the D2D communication control unit 200 requesting status information for the small cell APs 100;

S115: The small cell APs 100 transmit (uplink) each ID and information of user terminals in the access service to the D2D communication control unit 200, and the D2D communication control unit 200 is for each small cell AP 100. Updating and storing information of user terminals in the access service in the UE / AP map memory 290;

S120: The D2D communication control unit 200 transmits a connection request signal to a destination AP to which another user terminal called according to the information stored in the UE / AP map memory 290 is connected. Accessing the D to D communication by transmitting an access request signal to the small cell AP to which is connected;

S125: notifying that the D to D connection is established from the accessed small cell AP for the user terminal (UE) that has transmitted the access request signal:

S130: transmitting and receiving packets between the connected small cell AP and another user terminal called through the D2D communication control unit 200;

S135: the packet transmitted to the called other user terminal is transferred from the connected small cell AP to the D2D communication control unit 200;

S140: The D2D communication control unit 200 converts the uplinked packets into downlink packets;

S145: The D2D communication control unit 200 transmits the converted downlink packets through the small cell AP connected to the user terminal (UE) and the other user terminal called;

It consists of.

At this time, the D2D communication control unit 200 repeats from the step S105 if the D to D service termination request in step S145, and repeats from the step S110 if there is no D to D service termination request.

FIG. 10 is a method of driving a D-to-D system using a 5G small cell of the present invention, in which an external 5G connection is performed when a user terminal (UE) in a small cell calls another user terminal not located in the same small cell. A driving method is shown. The driving method will be described step by step as follows.

S200: transmitting a request signal for calling another user terminal from a user terminal UE located in the small cell;

S205: the small cell AP to which the user terminal (UE) which has sent the request signal is connected (uplink) transmitting an ID and other user terminal data called to the D2D communication control unit 200;

S210: the D2D communication control unit 200 requesting status information for the small cell APs 100;

S215: The small cell APs 100 transmit (uplink) each ID and information of user terminals in the access service to the D2D communication control unit 200, and the D2D communication control unit 200 is for each small cell AP 100. Updating and storing information of user terminals in the access service in the UE / AP map memory 290;

S220: the D2D communication control unit 200, transmitting an access request signal to a small cell AP to which a user terminal (UE) that has transmitted an access request signal is connected to connect external 5G communication;

S225: notifying that the external 5G connection is established from the connected small cell AP to the user terminal (UE) that has transmitted the access request signal:

S230: Uplink packets of the user equipment (UE) that have sent the access request signal are transmitted to the connected small cell AP;

S235: transmitting a packet transmitted to the small cell AP through a D2D communication control unit 200 and a DAS;

S235: the packet transmitted to the called other user terminal is transferred from the connected small cell AP to the D2D communication control unit 200 and transmitted to the macro cell or the core network through the DAS;

S240: downlinking of the packet from another called user terminal to the D2D communication control unit 200 from the macro cell or the core network;

S245: the D2D communication control unit 200 transmitting the received downlink packets to the user terminal (UE) through the small cell AP to which the user terminal (UE) which has transmitted the access request signal is connected;

It consists of.

If there is a connection termination request to the D2D communication control unit 200 in step S240, and repeats from step S205, if there is no connection termination request is repeated from step S210.

In the D-to-D system and the method using the 5G small cell of the present invention, the user terminal (UE) located in the service area of the small cell uses the 5G communication method as it is, and the terminal to be called is within the service area of the small cell. If it is located, it provides D to D access, and if the terminal to be called is not located in the service area of the small cell, it provides a D to D system and a method using a 5G small cell that uses a 5G communication network by connecting to a DAS. do. The D to D system and the method using the 5G small cell of the present invention, D to D connection between any terminal and the terminal located in the same 5G small cell without the search of the calling terminal for the D to D connection in the user terminal (UE) There is a feature to provide.

Although the D-to-D system and the method using the 5G small cell of the present invention described above are described by the limited embodiments and drawings, the present invention is not limited thereto and the present invention belongs to Various modifications and variations are possible to those skilled in the art without departing from the spirit of the present invention and equivalents of the claims to be described below.

100: small cell AP 110: main CPU
120: UE data memory 130: nonvolatile memory
140: packet synchronization clock 150: UE data processor
160: uplink interface 170: downlink interface
200: D to D communication controller 210: D to D communication processor
220: AP uplink communication unit 230: AP downlink communication unit
240: packet buffer 250: AP ID memory
260: packet clock 270: packet conversion unit
280: DAS interface 290: UE / AP map memory

Claims (10)

In a 5G mobile communication system, a small cell having at least one small cell AP 100, a D to D communication control unit 200 to which the small cell APs are connected, and the D to D communication control unit 200 are connected. In a D-to-D system using a 5G small cell composed of Distributed Antenna Systems (DAS),

A D to D communication controller 200 is provided between the small cell AP 100 and a distributed antenna system (DAS),
The D to D communication control unit 200 collects the user terminal and access small cell AP information in the small cell,
When information of a terminal called from the user terminal (UE) located in the small cell is received, if the called terminal is located in the small cell, D to D of the terminal to be called with the user terminal (UE) Perform a connection,
If the called terminal is not located in the small cell, the D-to-D system using the 5G small cell, characterized in that configured to perform 5G communication by connecting the UE to a distributed antenna system (DAS).
According to claim 1, wherein the small cell AP (100);
A main CPU 110 controlling the small cell AP 100;
UE for storing the ID of each small cell AP 100 and the information (for example, CID: caller ID) of the user terminal (UE) connected to the small cell AP 100 according to the small cell AP 100. Data memory 120;
A nonvolatile memory 130 in which a program and data for driving the main CPU 110 and an ID of each of the small cell APs 100 are stored;
A UE data processor 150 for detecting signal strength of a user terminal (UE) and detecting a data traffic amount;
An uplink interface 160 for packet communication with the D to D communication control unit 200 under control of the main CPU 110;
A downlink interface 170 for packet communication with user terminals (UEs) under the control of the main CPU 110;
A packet synchronization clock 140 for synchronously communicating the uplink packets with the downlink packets; D-to-D system using a 5G small cell, characterized in that consisting of
The method of claim 1, wherein the D to D communication control unit 200;
A D to D communication processor 210 for driving the D to D communication control unit 200;
An AP uplink communication unit 220 connected to the D to D communication processor 210 to receive uplink packets of the small cell APs 100;
An AP downlink communication unit 230 connected to the D to D communication processor 210 to provide downlink packets for the small cell APs 100;
A packet buffer for temporarily storing the uplink packets and the downlink packets;
An AP ID memory 250 for storing IDs of small cell APs 100 controlled by the D to D communication control unit 200;
A packet clock 260 for communicating the uplink packets and the downlink packets with small cell APs 100 in synchronization with a macro cell and a core network;
A packet converter 270 for rearranging uplink packets stored in the packet buffer 240 into downlink packets or converting downlink packets into uplink packets;
The D to D communication processor 210 connects the uplink packets and the downlink packets to a distributed antenna system (DAS) and provides or provides the macrocell and the core network through a backhaul network and a mobile communication switching center (MSC). Receiving DAS interface 280;
A UE / AP map memory 290 for storing information of a user terminal (UE) connected for each ID of the small cell APs 100 controlled by the D to D communication control unit 200;
D-to-D system using a 5G small cell, characterized in that consisting of
The method of claim 3, wherein the D to D communication control unit 200,
D-to-D using 5G small cell, characterized in that configured to provide the uplink packet of the small cell AP (100) by the D to D communication processor 210 to the macro cell and the core network via the DAS interface 280. D system.
The method of claim 3, wherein the D to D communication control unit 200,
D-D using 5G small cell, characterized in that configured to receive from the macro cell and the core network downlink packets for the small cell AP (100) via the DAS interface 280 by the D to D communication processor 210 to-D system.
The method of claim 3, wherein the D to D communication control unit 200,
The uplink packets received from the small cell APs 100 through the AP uplink communication unit 220 are converted into downlink packets through the packet conversion unit 270, and the small cell AP through the AP downlink communication unit 230. D-to-D system using a 5G small cell, characterized in that configured to provide 100).
As a driving method of D-to-D system using 5G small cell,
S100: transmitting a request signal for calling another user terminal from a user terminal UE located in the small cell;
S105: the small cell AP to which the user terminal (UE) which has sent the request signal is connected (uplink) transmitting an ID and other user terminal data called to the D2D communication control unit 200;
S110: the D2D communication control unit 200 requesting status information for the small cell APs 100;
S115: The small cell APs 100 transmit (uplink) each ID and information of user terminals in the access service to the D2D communication control unit 200, and the D2D communication control unit 200 is for each small cell AP 100. Updating and storing information of user terminals in the access service in the UE / AP map memory 290;
S120: The D2D communication control unit 200 transmits a connection request signal to a destination AP to which another user terminal called according to the information stored in the UE / AP map memory 290 is connected. Accessing the D to D communication by transmitting an access request signal to the small cell AP to which is connected;
S125: notifying that the D to D connection is established from the accessed small cell AP for the user terminal (UE) that has transmitted the access request signal:
S130: transmitting and receiving packets between the connected small cell AP and another user terminal called through the D2D communication control unit 200;
S135: the packet transmitted to the called other user terminal is transferred from the connected small cell AP to the D2D communication control unit 200;
S140: The D2D communication control unit 200 converts the uplinked packets into downlink packets;
S145: The D2D communication control unit 200 transmits the converted downlink packets through the small cell AP connected to the user terminal (UE) and the other user terminal called;
Driving method of D-to-D system using 5G small cell, characterized in that consisting of
The method of claim 7, wherein step S145,
If there is a request to terminate the D to D service is repeated from step S105,
If there is no request to terminate the D to D service, the method of driving a D-to-D system using a 5G small cell, further comprising the step of repeating from the step S110.
As a driving method of D-to-D system using 5G small cell,
S200: transmitting a request signal for calling another user terminal from a user terminal UE located in the small cell;
S205: the small cell AP to which the user terminal (UE) which has sent the request signal is connected (uplink) transmitting an ID and other user terminal data called to the D2D communication control unit 200;
S210: the D2D communication control unit 200 requesting status information for the small cell APs 100;
S215: The small cell APs 100 transmit (uplink) each ID and information of user terminals in the access service to the D2D communication control unit 200, and the D2D communication control unit 200 is for each small cell AP 100. Updating and storing information of user terminals in the access service in the UE / AP map memory 290;
S220: the D2D communication control unit 200, transmitting an access request signal to a small cell AP to which a user terminal (UE) that has transmitted an access request signal is connected to connect external 5G communication;
S225: notifying that the external 5G connection is established from the connected small cell AP to the user terminal (UE) that has transmitted the access request signal:
S230: Uplink packets of the user equipment (UE) that have sent the access request signal are transmitted to the connected small cell AP;
S235: transmitting a packet transmitted to the small cell AP through a D2D communication control unit 200 and a DAS;
S235: the packet transmitted to the called other user terminal is transferred from the connected small cell AP to the D2D communication control unit 200 and transmitted to the macro cell or the core network through the DAS;
S240: downlinking of the packet from another called user terminal to the D2D communication control unit 200 from the macro cell or the core network;
S245: the D2D communication control unit 200 transmitting the received downlink packets to the user terminal (UE) through the small cell AP to which the user terminal (UE) which has transmitted the access request signal is connected;
Driving method of D-to-D system using 5G small cell, characterized in that consisting of
The method of claim 9, wherein step S240,
If there is a connection termination request to the D2D communication control unit 200 repeats from S205,
If there is no access termination request, the method of driving a D-to-D system using a 5G small cell, further comprising the step of repeatedly performing from the step S210.

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