KR20210086327A - Method for handover of user euipment in 5g remote acess network - Google Patents

Abstract

The present invention provides a handover method of a 5G communication system, which does not generate a procedure through a core network when handover occurs, and performs all the procedures of handover through MEC equipped with an AMF function to perform handover in a less delay time when proceeding through MEC than the existing handover, as a method for handover of user equipment (UE) in a 5G radio access network (5G-RAN). The method for handover of UE in a 5G-RAN includes the steps of: determining handover from a source cell to a target cell by UE; transmitting, by the source cell, a handover requirement message to the target cell; and receiving a handover command message from the target cell and transmitting the handover command message to the UE.

Description

A handover method of a terminal in a 5G radio access network {METHOD FOR HANDOVER OF USER EUIPMENT IN 5G REMOTE ACESS NETWORK}

The present invention relates to a handover method of a terminal in a 5G radio access network.

Current LTE (Long Term Evolution)) or if the 5G (5 ^th Generation) communication system, a UE (User Equipment, UE) node (gNodeb) and 1 is connected to 1, the wireless more associated nodes, these terminals due to the movement A handover occurs when another node with a stronger signal connection strength is detected, and when such handover occurs, data link through MME (Mobility Management Entity) or AMF (Access and Mobility Management) of the core network Procedures such as re-routing and re-establishing the control interface are required.

The 5G communication system introduced MEC (Mobile Edge Computing) for ultra-low latency service. If the service is installed in the MEC at the edge, the service can be used through the MEC instead of through the core network when a user requests a service.

However, when a user uses a service while moving, a procedure through the core network occurs when a handover occurs, and in this case, it is difficult for the 5G communication system to provide an ultra-low latency service.

In the present invention, when handover occurs in 5G network, all procedures are performed through MEC equipped with AMF function without going through the core network, so that handover can be performed with a lower delay time compared to the existing handover. make it possible

The present invention is a handover method of a horse in a 5G radio access network (5G-RAN),

determining a handover of a terminal (UE) from a source cell to a target cell;

Transmitting, by the source cell 200, a handover request message (handover requirement message) to the target cell 300;

Upon receiving the handover command message from the target cell 300 , the handover command message is transmitted to the UE, and the handover message is transmitted by the UE from the source cell 200 to the target cell 300 . It is set to be over and may include at least one processor configured to perform indirect data forwarding.

In the communication system, both the mapper source cell and the target cell may be connected to the same MEC.

The communication system is connected to the central cloud through a user plane function (UPF),

The user plane functional unit is connected to EC (Mobile Edge Computing),

The MEC may include a data path setting function unit and a control interface setting function unit.

The method includes the steps of: the target cell 300 transmitting a path conversion request to the MEC (400); and

The method may further include; setting a path conversion between the user plane function unit 500 and the target cell 300 .

The method may further include, by the user plane function unit 500 , transmitting an end marker signal to the target cell 300 .

The method comprises: transmitting, by the MEC (400), a path conversion request reception signal to the target cell (300); and

The target cell 300 may further include transmitting a UE context release signal to the source cell 200 .

In the present invention, when a user uses a service while moving, a procedure through the core network does not occur when a handover occurs, and all handover procedures are performed through the MEC equipped with the AMF function, compared to the existing handover MEC. Provides a handover method of a 5G communication system that can perform handover with a lower delay time when proceeding through .

1 illustrates a situation in which handover occurs in the configuration of a 5G communication system according to an embodiment of the present invention.
2 illustrates a step in which handover occurs in the configuration of a 5G communication system according to an embodiment of the present invention.
FIG. 3 illustrates a step in which handover occurs in the configuration of a 5G communication system following FIG. 2 according to an embodiment of the present invention.
4 is a block diagram illustrating the configuration of a terminal 1300 according to an embodiment of the present invention.
5 is a block diagram illustrating a configuration of a base station 1400 according to an embodiment of the present invention.

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

In describing embodiments in the present specification, descriptions of technical contents that are well known in the technical field to which the present invention pertains and are not directly related to the present invention will be omitted. This is to more clearly convey the gist of the present invention without obscuring the gist of the present invention by omitting unnecessary description.

For the same reason, some components are exaggerated, omitted, or schematically illustrated in the accompanying drawings. In addition, the size of each component does not fully reflect the actual size. In each figure, the same or corresponding elements are assigned the same reference numerals.

Advantages and features of the present invention, and a method for achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains. It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

At this time, it will be understood that each block of the flowchart diagrams and combinations of the flowchart diagrams may be performed by computer program instructions. These computer program instructions may be embodied in a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, such that the instructions performed by the processor of the computer or other programmable data processing equipment are not described in the flowchart block(s). It creates a means to perform functions. These computer program instructions may also be stored in a computer-usable or computer-readable memory that may direct a computer or other programmable data processing equipment to implement a function in a particular manner, and thus the computer-usable or computer-readable memory. It is also possible that the instructions stored in the flow chart block(s) produce an article of manufacture containing instruction means for performing the function described in the flowchart block(s). The computer program instructions may also be mounted on a computer or other programmable data processing equipment, such that a series of operational steps are performed on the computer or other programmable data processing equipment to create a computer-executed process to create a computer or other programmable data processing equipment. It is also possible that instructions for performing the processing equipment provide steps for performing the functions described in the flowchart block(s).

Additionally, each block may represent a module, segment, or portion of code that includes one or more executable instructions for executing specified logical function(s). It should also be noted that in some alternative implementations it is also possible for the functions recited in blocks to occur out of order. For example, two blocks shown one after another may in fact be performed substantially simultaneously, or it is possible that the blocks are sometimes performed in the reverse order according to the corresponding function.

In this case, the term '~ unit' used in this embodiment means software or hardware components such as FPGA or ASIC, and '~ unit' performs certain roles. However, '~ part' is not limited to software or hardware. The '~ unit' may be configured to reside on an addressable storage medium or may be configured to replay one or more processors. Thus, as an example, '~' denotes components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, and procedures. , subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functions provided in the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. In addition, components and '~ units' may be implemented to play one or more CPUs in a device or secure multimedia card.

A terminal in the present invention may generally include a mobile terminal, and may indicate a device that has been subscribed to a mobile communication system and is provided with a service from the mobile communication system. The mobile terminal may include a smart device such as a smart phone or a tablet PC, which corresponds to an example and the present invention is not limited thereto.

The cellular wireless communication system performs a handover procedure when it is necessary to change the serving cell of the mobile terminal. For example, when it is difficult for a terminal to communicate with a source cell to perform communication due to disconnection by an obstacle, or when the terminal moves from an area within a source cell to an area of a target cell may perform handover to the target cell.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 illustrates a situation in which handover occurs in the configuration of a 5G communication system according to an embodiment of the present invention.

In a situation in which a UE (User Equipment, UE) is connected to the source cell 200 , the signal strength of the target cell 300 is stronger, and when the UE decides to perform handover to the target cell, in the prior art, the central cloud 600 ), it was difficult to achieve ultra-low delay in the handover process by performing handover in the Access and Mobility Management Function (AMF) of ), but the communication system according to the present invention provides a user plane function unit (a gateway in charge of the user plane) MEC (Mobile Edge Computing), a general-purpose server that performs various functions, is connected to User Plane Function (UPF), and this MEC includes a data path setting function unit and a control interface setting function unit, and the AMF of the central cloud 600 may perform the function of re-establishing the data link path and re-establishing the control interface. The MEC 400 may be connected to the UPF 500 to perform a high-speed handover at an edge close to the terminal to achieve ultra-low latency of the 5G communication system.

However, in the communication system according to the present invention, ultra-low delay and high-speed handover to the MEC 400 can be performed only for handover when both the source cell 200 and the target cell 300 are connected to the MEC 400 . , when the source cell 200 and the target cell 300 are not connected to the same MEC 400 , handover may be performed in the AMF of the central cloud 600 in a conventional manner.

2 illustrates a step in which handover occurs in the configuration of a 5G communication system according to an embodiment of the present invention.

First, in step S110 , the terminal 100 may transmit a measurement report to the source cell 200 . For example, the terminal 100 accessing the source cell 200 and performing communication may periodically measure the signal level and report it to the source cell 200 . Specifically, the terminal 100 may be set for a preset condition or reporting period for measurement report. In addition, the terminal 100 may perform the measurement report according to the setting, when the preset condition is satisfied, or according to a preset reporting period.

In step S111, the source cell 200 may determine a headover. For example, the source cell 200 or the terminal 100 may determine a target cell to perform handover based on the candidate cell information.

When handover to the target cell 300 is determined by the terminal 100 , the terminal 100 may perform initial access with the target cell 300 through a random access process.

First, in step S110 , the terminal 100 may transmit a measurement report to the source cell 200 .

And in step S111, the source cell 200 may determine a handover. For example, the source cell 200 may determine a target cell to perform handover based on the measurement report received from the terminal 100 .

When the source cell 200 and the target cell 300 are cells of different base stations, in step S111 , the source cell 200 may transmit a handover request to the target cell 300 . In this case, the source cell 200 may transmit an updated security key based on a physical cell ID (PCID) of the target cell 300 .

In step S113 , the target cell 300 that has determined that the handover is acceptable may transmit a handover request response to the source cell 200 ( S114 ).

In step S150 , the source cell 200 receiving the handover request response may transmit an RRC connection reconfiguration message including movement control information to the terminal 100 . In this case, the source cell 200 may initialize the RAN handover by transmitting information on the target cell 300 to which the handover is to be performed to the terminal 100 together (S115).

Meanwhile, in step S117 , when the source cell 200 and the target cell 300 are cells of different base stations, in step S235 , the source cell 200 is the target cell 300 with a sequence number. number status, hereinafter SNstatus) may be transmitted. Specifically, the source cell 200 transmits the sequence number of the packet of the PDCP layer to the target cell 300 through the interface between the base stations, and informs which packet to transmit and receive to the terminal 100 after the handover is completed. can

The terminal 100 may transmit an RRC connection reconfiguration complete message to the target cell 300 to complete the connection with the target cell 300, and in step S116, the terminal 100 sends the source The connection with the cell 200 may be released and synchronization with the target cell 300 may be performed.

FIG. 3 illustrates a step in which handover occurs in the configuration of a 5G communication system following FIG. 2 according to an embodiment of the present invention.

4 is a block diagram illustrating a configuration of a terminal 1300 according to an embodiment of the present invention. The terminal 1300 may include a transceiver 1310 and a control unit 1320 .

The transceiver 1310 is a component for transmitting and receiving a signal.

And the control unit 1320 is a component for controlling the terminal 1300 as a whole. Specifically, the controller 1320 may control the transceiver 1310 to receive a message including information on at least one target cell for performing fast handover from a source cell.

In addition, the controller 1320 may control to perform the fast handover by reusing the radio bearer based on previously received information.

In addition, the control unit 1320 reuses a security key corresponding to the source cell and a radio bearer of a packet data convergence protocol (PDCP) and radio link control (RLC) to perform the high-speed handover. can be done

In addition, when the fast handover procedure is completed, the controller 1320 may control the transceiver 1310 to transmit a handover completion message including a new terminal identifier to the target cell. The security key and PDCP/RLC radio bearer corresponding to the source cell may be reused by the target cell that has received the handover completion message including the new terminal identifier.

Meanwhile, the controller 1320 may control the operation of the terminal 1300 in all the above-described embodiments as well as the above contents.

5 is a block diagram illustrating a configuration of a base station 1400 according to an embodiment of the present invention. The base station 1400 may include a transceiver 1410 and a controller 1420 .

The transceiver 1410 is a component for transmitting and receiving a signal.

And the control unit 1420 is a component for controlling the base station 1400 as a whole.

First, the base station 1400 may perform fast HO between a source cell and a target cell within a cell (intra). In this case, the controller 1420 may be included in each of the source cell and the target cell to control the operation of each cell. However, this is only an embodiment, and the controller 1420 may be included in the base station 1400 to control the operation of the source cell and the target cell.

First, when the control unit 1420 is a source cell or a control unit of the base station 1400, the control unit 1420 controls the transceiver 1410 to receive a measurement report including a measurement result for at least one cell from the terminal. can be controlled In addition, the controller 1420 may determine at least one target cell capable of performing fast handover that reuses a radio bearer based on the measurement report.

For example, the controller 1420 may determine another cell in the base station 1400 as a target cell to perform fast HO, based on the measurement report.

Also, the controller 1420 may control the transceiver to transmit information on the determined at least one target cell to the terminal.

Meanwhile, when performing the high-speed handover, a security key corresponding to the source cell, a packet data convergence protocol (PDCP), and a radio bearer of radio link control (RLC) are connected to the terminal and the target cell. can be reused by

In addition, when the control unit 1420 is the control unit of the base station 1400, the control unit 1420, in the at least one target cell, the terminal and the target cell on which the high-speed handover is performed is the same as the source cell of the base station. In the case of a cell, it is possible to control to skip the security key and the PDCP/RLC reset. Such an operation may be performed by the control unit of the target cell when there is a separate control unit of the target cell.

On the other hand, when the target cell on which the fast handover is performed is a cell of a base station different from the source cell, and the control unit 1420 is the control unit of the source cell, the security key and the PDCP/RLC radio bearer are transmitted to the target cell. The transceiver 1410 may be controlled to transmit information on .

In the at least one target cell, when the terminal and the target cell to which the fast handover is performed are cells of a base station different from the source cell, when the control unit 1420 is the control unit of the source cell, the RLC sequence number status ( The transceiver 1410 may be controlled to transmit a sequence number status) to the target cell.

On the other hand, when the controller 1420 is the controller of the target cell, the controller 1420 controls the transceiver 1410 to receive a handover message including a new terminal identifier from the terminal upon completion of the high-speed handover, Based on the new terminal identifier of the received message, to reuse the security key corresponding to the source cell and the radio bearer of the packet data convergence protocol (PDCP) and radio link control (RLC) can be controlled

In addition, when the target cell is a cell of a base station different from the source cell, the controller 1420 controls the transceiver 1410 to receive the security key and information on the PDCP/RLC radio bearer, Based on the received information, it is possible to control to reuse the security key corresponding to the source cell and the PDCP/RLC radio bearer.

In addition, when the target cell is a cell of a base station different from the source cell, the controller 1420 may control the transceiver 1410 to receive an RLC sequence number status from the source cell.

When the source cell and the target cell are cells of separate base stations, the above operations may be performed by each of the control units of the cells.

Meanwhile, the controller 1420 may control the operation of the base station 1400 in all the above-described embodiments as well as the above contents.

The components of the above-described terminal and base station may be implemented in software. For example, the control unit of the terminal and the base station may further include a flash memory or other non-volatile memory. Programs for performing respective roles of the control unit may be stored in the non-volatile memory.

In addition, the control unit of the terminal and the base station may be implemented in a form including a CPU and a random access memory (RAM). The CPU of the control unit may copy the above-described programs stored in the non-volatile memory to the RAM and then execute the copied programs to perform the functions of the terminal as described above.

The control unit is a component responsible for controlling the terminal and the base station. The control unit may be used interchangeably with the same meaning as a central processing unit, a microprocessor, a processor, and an operating system. In addition, the control unit of the terminal and the base station may be implemented as a single-chip system (System-on-a-chip or System on chip, SOC, SoC) together with other functional units such as a communication module included in the terminal.

Meanwhile, the method of the terminal and the base station according to the above-described various embodiments may be coded with software and stored in a non-transitory readable medium. Such a non-transitory readable medium may be mounted and used in various devices.

The non-transitory readable medium refers to a medium that stores data semi-permanently, rather than a medium that stores data for a short moment, such as a register, cache, memory, etc., and can be read by a device. Specifically, it may be a CD, DVD, hard disk, Blu-ray disk, USB, memory card, ROM, or the like.

In addition, although preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and the technical field to which the present invention belongs without departing from the gist of the present invention as claimed in the claims In addition, various modifications may be made by those of ordinary skill in the art, and these modifications should not be individually understood from the technical spirit or perspective of the present invention.

Claims (6)

As a handover method of a horse in a 5G radio access network (5G-RAN),
determining a handover of a terminal (UE) from a source cell to a target cell;
Transmitting, by the source cell 200, a handover request message (handover requirement message) to the target cell 300;
Upon receiving the handover command message from the target cell 300 , the handover command message is transmitted to the UE, and the handover message is transmitted by the UE from the source cell 200 to the target cell 300 . A method comprising at least one processor configured to be overridden and configured to perform indirect data forwarding. According to claim 1,
The source cell and the target cell are both connected to the same MEC. According to claim 1,
The communication system is connected to the central cloud through a user plane function (UPF),
The user plane functional unit is connected to EC (Mobile Edge Computing),
wherein the MEC includes a data path setting function unit and a control interface setting function unit. 4. The method of claim 3,
The method includes the steps of: the target cell 300 transmitting a path conversion request to the MEC (400); and
The handover method further comprising; setting a path conversion between the user plane function unit 500 and the target cell 300 . 4. The method of claim 3,
The method further comprises the step of the user plane function unit (500) sending an end marker signal to the target cell (300). 4. The method of claim 3,
The method comprises: transmitting, by the MEC (400), a path conversion request reception signal to the target cell (300); and
The handover method, further comprising the target cell (300) sending a UE context release signal to the source cell (200).

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