Method for performing RLC migration in wireless network system and electronic device for performing method

Abstract

Disclosed are a method and an electronic device for performing RLC migration in a wireless network system. The method comprises the steps of: identifying, on the basis of a scaling situation, a source RLC of a first distributed unit (DU) to which data is to be migrated and a target RLC of a second DU to which data is to be migrated from the source RLC; issuing a command for data forwarding from the source RLC to the target RLC; identifying a downlink reference sequence number for downlink data obtained from a centralized unit (CU) on the basis of a forwarding command time point; delivering the migration information of the source RLC to the target RLC; transmitting downlink data processed from one of the source RLC or the target RLC to a medium access control (MAC) of the second DU on the basis of the downlink reference sequence number; and changing the F1-U interface of the CU to the CU and the target RLC.

Description

Method for performing RLC transfer in a wireless network system and electronic device for performing the method

[0001] Embodiments disclosed in this document relate to a method for performing RLC transfer in a wireless network system and an electronic device for performing the method.

[0002] In a radio access network (RAN) system, one cell site is connected to a distributed unit (DU), and the processing (or conversion) capacity of the distributed unit is determined by the maximum traffic that can enter the cell site. Except during peak traffic times, the DU's resources are not utilized.

[0003] A virtualized RAN (vRAN) system can perform the functions of a radio access network by virtualizing a DU or CU (centralized unit) into a vDU (virtualized DU) and vCU (virtualized CU) based on software rather than hardware and running them through a general server device.

[0004] A DU and a cell site (e.g., a set of RUs) in a wireless access network can form a 1:1 connection relationship with each other. In a virtual wireless access network, vDU pooling can break this 1:1 connection relationship and reduce the number of servers by virtualizing through DU pooling.

[0005] The present disclosure can be implemented in various ways, including as a method, system, device, or computer program stored on a computer-readable storage medium.

[0006] In one embodiment of the present disclosure, a method for performing RLC (radio link control) migration of a wireless network system may include a step of identifying a source RLC of a first distributed unit (DU) to which data is to be migrated and a target RLC of a second DU to which data is to be migrated, based on a scaling situation. In one embodiment of the present disclosure, the method may include a step of transmitting a data forwarding command from the source RLC to the target RLC to the source RLC. In one embodiment of the present disclosure, the method may include a step of identifying a downlink reference sequence number for downlink data obtained from a centralized unit (CU) based on a timing of the data forwarding command. In one embodiment of the present disclosure, the method may include a step of transmitting migration information of the source RLC to the target RLC. In one embodiment of the present disclosure, the method may include a step of transmitting the downlink data processed from one of the source RLC or the target RLC to a medium access control (MAC) of the second DU based on the downlink reference sequence number. In one embodiment of the present disclosure, the step of changing the F1-U interface of the CU to the CU and the target RLC may be included.

[0007] In one embodiment of the present disclosure, a program for performing the method on a computer can be recorded on a computer-readable recording medium.

[0008] In one embodiment of the present disclosure, an electronic device for performing RLC (radio link control) migration of a wireless network system may include a memory storing one or more instructions; and at least one processor for executing the one or more instructions stored in the memory. In one embodiment of the present disclosure, the at least one processor may, by executing the one or more instructions, cause the electronic device to identify a source RLC of a first distributed unit (DU) to which data is to be migrated and a target RLC of a second DU to which data is to be migrated from the source RLC, based on a scaling situation. In one embodiment of the present disclosure, the at least one processor may, by executing the one or more instructions, cause the electronic device to transmit a data forwarding command from the source RLC to the target RLC to the source RLC. In one embodiment of the present disclosure, the at least one processor may cause the electronic device to identify a downlink reference sequence number for downlink data obtained from a centralized unit (CU) based on the forwarding command time point by executing the one or more commands. In one embodiment of the present disclosure, the at least one processor may cause the electronic device to transfer previous information of the source RLC to the target RLC by executing the one or more commands. In one embodiment of the present disclosure, the at least one processor may cause the electronic device to transfer the downlink data processed from one of the source RLC or the target RLC based on the downlink reference sequence number to a MAC (medium access control) of the second DU by executing the one or more commands.In one embodiment of the present disclosure, the at least one processor may cause the electronic device to change the F1-U interface of the CU to the CU and the target RLC by executing the one or more instructions.

[0009] FIG. 1 is a block diagram illustrating a virtual wireless access network and a core network according to one embodiment.

[0010] FIG. 2a is a block diagram showing a scale-out situation of a DU according to one embodiment.

[0011] FIG. 2b is a block diagram illustrating a scale-in situation of a DU according to one embodiment.

[0012] Figure 3 illustrates RLC transfer of DU according to one embodiment.

[0013] FIG. 4 is a flowchart illustrating a method for performing RLC transfer of a DU according to one embodiment.

[0014] FIG. 5a is a block diagram illustrating a flow for transmitting downlink data before RLC transfer according to one embodiment.

[0015] FIG. 5b illustrates a flow for transmitting downlink data when RLC is transferred according to one embodiment.

[0016] FIG. 5c illustrates a flow for transmitting downlink data after RLC transfer is completed according to one embodiment.

[0017] FIG. 6 illustrates a flow for transferring UE context in a virtual wireless access network according to one embodiment.

[0018] FIG. 7 illustrates a flow of forwarding RLC data and transmitting data between a source RLC and a target RLC in a virtual wireless access network according to one embodiment.

[0019] Figure 8 illustrates downlink data stored in a source RLC according to one embodiment.

[0020] FIG. 9 illustrates a flow for changing the F1-U path of a CU in a virtual wireless access network according to one embodiment.

[0021] FIG. 10 illustrates a method for performing RLC transfer of DU for uplink data in a virtual wireless access network according to one embodiment.

[0022] FIG. 11a is a block diagram illustrating a flow for transmitting uplink data before RLC transfer according to one embodiment.

[0023] Figure 11b illustrates a flow for transmitting uplink data when RLC is transferred according to one embodiment.

[0024] Figure 11c illustrates a flow for transmitting uplink data after RLC transfer is completed according to one embodiment.

[0025] Figure 12 illustrates a flow for transmitting uplink data during RLC transfer according to one embodiment.

[0026] Figure 13 illustrates uplink data stored in a buffer of a source RLC according to one embodiment.

[0027] Figure 14 illustrates a flow for changing a MAC-RLC path and transmitting uplink data according to one embodiment.

[0028] FIG. 15 is a flowchart illustrating a method for transmitting a reception status message of a user device to a source RLC or a target RLC according to one embodiment.

[0029] FIG. 16a is a block diagram illustrating a path for processing a reception status message before an RLC-MAC path is changed according to one embodiment.

[0030] FIG. 16b is a block diagram illustrating a path for processing a reception status message after an RLC-MAC path is changed according to one embodiment.

[0031] Figure 17 illustrates a flow for transmitting RLC transfer and reception status messages according to one embodiment.

[0032] Figure 18 illustrates downlink data stored in user equipment according to one embodiment.

[0033] FIG. 19 illustrates a reception status message to be processed by a source RLC and a target RLC, which are generated by dividing a reception status message according to one embodiment.

[0034] FIG. 20 is a block diagram illustrating an electronic device according to one embodiment.

[0035] In this disclosure, the expression “at least one of a, b or c” may refer to “a”, “b”, “c”, “a and b”, “a and c”, “b and c”, “all of a, b and c”, or variations thereof.

[0036] The terms used in this disclosure are selected from widely used, common terms, taking into account the functions of the disclosure. However, these terms may vary depending on the intentions of those skilled in the art, precedents, the emergence of new technologies, etc. Furthermore, in certain cases, terms may be arbitrarily selected by the applicant, in which case their meanings will be described in detail in the relevant description. Therefore, the terms used in this disclosure should not be defined simply as names, but rather based on the meanings of the terms and the overall content of the disclosure.

[0037] Singular expressions may include plural expressions unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art described herein. Furthermore, terms containing ordinal numbers, such as "first" or "second," used herein may be used to describe various components, but such components should not be limited by such terms. Such terms are used solely to distinguish one component from another.

[0038] When a part of the specification is said to "include" a component, this does not exclude other components, but rather implies the inclusion of other components, unless otherwise specifically stated. Furthermore, terms such as "part" and "module" used in the specification mean a unit that processes (or converts) at least one function or operation, which may be implemented in hardware, software, or a combination of hardware and software.

[0039] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings so that those skilled in the art can easily practice the present disclosure. However, the present disclosure may be implemented in various different forms and is not limited to the embodiments described herein. In addition, in the drawings, parts that are not related to the description are omitted to clearly explain the present disclosure, and similar parts are designated with similar reference numerals throughout the specification. In addition, the reference numerals used in each drawing are only for the purpose of describing each drawing, and different reference numerals used in different drawings do not indicate different elements.

[0040] Throughout the specification, when a part is said to be "connected" to another part, this includes not only "directly connected" or "physically connected," but also "electrically connected" with another element in between. In this disclosure, the terms "transmit," "receive," and "communicate" include both direct and indirect communication. Furthermore, when a part is said to "include" or "comprise" a component, this does not exclude other components, but rather includes other components, unless otherwise specifically stated.

[0041] Throughout this disclosure, unless specifically stated otherwise, “or” is inclusive and not exclusive. Thus, unless explicitly indicated otherwise or the context dictates otherwise, “A or B” can mean “A, B, or both.” As used herein, the phrases “at least one of” or “one or more of” can mean that different combinations of one or more of the listed items can be used, or that only any one of the listed items is required. For example, “at least one of A, B, and C” can include any of the following combinations: A, B, C, A and B, A and C, B and C, or A and B and C.

[0042] A "controller" can refer to any device, system, or part thereof that controls at least one operation. A controller can be implemented in hardware, a combination of hardware and software, or firmware. The functions associated with a particular controller can be centralized or distributed, localized or remote.

[0043] Additionally, the computer-readable medium may be provided in the form of a non-transitory storage medium. Here, a 'non-transitory storage medium' is a tangible device and may exclude wired, wireless, optical, or other communication links that transmit temporary electrical or other signals. Meanwhile, this 'non-transitory storage medium' does not distinguish between cases where data is permanently stored in the storage medium and cases where it is temporarily stored. For example, a 'non-transitory storage medium' may include a buffer where data is temporarily stored. The computer-readable medium may be any available medium that can be accessed by a computer, and may include both volatile and non-volatile media, and removable and non-removable media. The computer-readable medium includes media on which data can be permanently stored and media on which data can be stored and later overwritten, such as a rewritable optical disk or an erasable memory device.

[0044] According to one embodiment, the method according to various embodiments disclosed in the present document may be provided as a computer program product. The computer program product may be traded between sellers and buyers as a product. The computer program product may be distributed in the form of a device-readable storage medium (e.g., compact disc read only memory (CD-ROM)) or may be provided through an application store (e.g., Play Store). TM) or directly between two user devices (e.g., smartphones), online distribution (e.g., downloading or uploading). In the case of online distribution, at least a portion of the computer program product (e.g., downloadable app) may be at least temporarily stored or temporarily created in a device-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or an intermediary server.

[0045] Definitions for other specific words and phrases may be provided throughout this disclosure. Those skilled in the art will understand that, in various instances, the defined words and phrases may apply to past and future usages.

[0046] Each component described later in this specification may additionally perform some or all of the functions performed by other components in addition to its own main function, and some of the main functions of each component may be performed entirely by other components.

[0047] In the present disclosure, the term "scaling" may refer to an operation of moving a determined configuration of a DU to another DU according to predetermined criteria. Additionally, the term "scaling" may include an operation of creating a DU to which a cell will be moved before moving a cell, or deleting a DU from which a cell has been moved after moving a cell. Furthermore, the term "scaling" may be used as a general term for a scale-in process and a scale-out operation.

[0048] In the present disclosure, the term "scale-in" may include an operation of removing DUs determined to be scale-in targets from a DU pool containing DUs in a wireless network system based on predetermined criteria. Furthermore, the scale-in operation may reduce the number of DUs that no longer require processing (or conversion), thereby reducing the required resources.

[0049] In the present disclosure, the term "scale-out" may include a series of operations that determine a DU as a scale-out target based on predetermined criteria, create a new DU, and transfer data of the DU as a scale-out target to the created DU to distribute the processing (or transformation) amount. In other words, scale-out can improve overall performance by adding a DU with similar specifications to share the load of the existing DU when the capacity or performance of the DU reaches its limit.

[0050] In one embodiment of the present disclosure, "migration" may refer to a series of processes for moving data from a source DU determined as a scale target to another target DU in scaling. For example, DU "migration" may include the transfer of at least one of information, context, or interface associated with the source DU. In the present disclosure, the term "migration" may be used interchangeably with "transfer," "movement," and "migration."

[0051] In one embodiment of the present disclosure, a source DU may be determined as a scale target and may represent a DU to which its data is transferred, and a source RLC may be determined as a scale target and may represent an RLC to which its data is transferred.

[0052] In one embodiment of the present disclosure, the target DU may be determined as a scale target and may indicate a DU to which data is to be transferred from a source DU, and the target RLC may be determined as a scale target and may indicate an RLC to which data is to be transferred from a source RLC.

[0053] In one embodiment of the present disclosure, an 'RLC transfer' may include a transfer of at least one of information, context, or interface associated with RLC. For example, an "RLC transfer" may include a transfer of RLC configuration information. For example, an "RLC transfer" may be a transfer on a per-RLC basis, including a transfer of RLC configuration information and a UE context of a UE (user equipment) associated with RLC. For example, an "RLC transfer" may be a transfer on a per-UE basis, including a transfer of a UE context of a UE (user equipment) associated with RLC. For example, an "RLC transfer" may be a transfer on a per-UE basis, including a transfer of an interface for user data (e.g., an F1-U interface).

[0054] In one embodiment of the present disclosure, the 'UE context' may include information for wireless communication of the UE in a wireless communication system. For example, the 'UE context' may include location information of the UE, a terminal identifier, a status of the UE, service requirements, information on the network and cell currently in use, performance information of the UE, function information, security information, or authentication information. For example, the 'UE context' may include a unique number for each situation of UEs connected to a base station (e.g., radio network temporary identifier (RNTI)), information on DL Data Volume per UE (e.g., buffer occupancy (BO)), information on UL Data Volume per UE (e.g., buffer status report (BSR)), a physical downlink control channel (PDCCH) monitoring period for the UE to transmit and receive new DL / UL traffic (e.g., discontinuous reception (DRX)), and retransmission information per UE (e.g., hybrid automatic repeat request (HARQ) information). For example, a "UE context" may include different parameter values ​​or data for each of multiple UEs associated with the same cell. For example, a "UE context" may include common or shared parameter values ​​or data for multiple UEs associated with the same cell.

[0055] In one embodiment of the present disclosure, a 'UE associated with a cell' may include a UE associated with a cell, a UE attached to a cell, a UE communicating with an RU including a cell (i.e., transmitting and receiving data), a UE receiving a communication service via a cell, a UE transmitting and receiving data via a cell, a UE accessing a network via a cell, a UE included in a range (e.g., effective range, communication range) of a cell, a UE requesting a radio resource of a cell, or a UE allocated a radio resource of a cell, etc. For example, one or more UEs associated with a target cell may have a connection established and managed based on cell configuration information for the target cell.

[0056] In one embodiment of the present disclosure, "downlink data" may include all data destined for a user device in a wireless communication system. For example, "downlink data" may include data configured for reception by the user device and an acknowledgement (ACK) or negative acknowledgement (ACK) message to the user device.

[0057] Additionally, in the present disclosure, all types of data destined for a user device may be considered "downlink data," even if the user device does not receive the data. For example, when a base station transmits data to a core network, the core network forwards the data to a CU, and the CU processes (or converts) and forwards the data to a DU, even if the user device does not directly receive the data, all data during the data transmission process is destined for the user device, and thus may be considered "downlink data."

[0058] In one embodiment of the present disclosure, "uplink data" may include all data directed from a user device toward a base station in a wireless communication system. For example, "uplink data" may include capability information for the user device and a positive or negative response message indicating whether the user device has fully received downlink data.

[0059] Additionally, any type of data directed from a user device toward a base station can be considered "uplink data." For example, if a user device transmits data to a base station (RU), the RU transmits data to a base station (DU), and the DU transmits data to a base station (CU), all data transmitted during the data transmission process, even if the user device does not directly transmit the data, can be considered "uplink data" because it is directed toward the base station.

[0060] In one embodiment of the present disclosure, a "path" or "interface" may include the meaning of a module (e.g., a software module, a hardware module) that enables data transmission and reception. In one embodiment of the present disclosure, a "path" or "interface" may include the meaning of a logical or physical connection relationship. In one embodiment of the present disclosure, a "path" or "interface" may include the meaning of a data transmission and reception path. In one embodiment of the present disclosure, "establishing an interface between A and B" may include the meaning of establishing a connection so that A and B can transmit and receive data with each other and process (or convert) the received data.

[0061] FIG. 1 is a block diagram illustrating a virtual wireless access network and a core network according to one embodiment.

[0062] Referring to FIG. 1, a virtualized random access network (v-RAN) 100 may include a centralized unit (CU) 110, an operation administration maintenance (OAM) 120, N DUs from the first distributed unit (DU) 1 (130_1) to the Nth DU N (130_2), and a plurality of radio units (RUs) 140_1, 140_2, 140_3, 140_4) connected to each DU. The virtualized random access network (100) according to one embodiment may connect a core network (10) and a plurality of user devices (UEs) 20. For example, the virtualized random access network (100) may transmit data and signals between a base station and a user device using a wireless access technology. For example, the virtual wireless access network (100) can process initial connection of a user device, data transmission between a base station and a user device, transmission and reception of user data and control commands between a core network (10) and a user device (20), and QoS (Quality of Service) control for each terminal service.

[0063] According to one embodiment, the core network (10) is the center of a mobile communications network and can play a role in controlling and managing the core functions of the mobile communications system. For example, the core network (10) can perform functions such as user authentication and identification, line control, location management, and service provision. For example, the core network (10) may include user authentication information for each telecommunications company, and may include a platform network that is wired and connected to servers and systems of various service providers via optical cables.

[0064] In one embodiment of the present disclosure, the virtual wireless access network (100) may include a 5GS (5G system), 4GS, or other known wireless communication system, and may include a wireless communication system to be developed in the future.

[0065] According to one embodiment, a virtual wireless access network (100) uses software technology and virtualization technology to virtualize part or all of a network structure within a base station and an access network, so that each network structure can be managed from a centralized data center or cloud. For example, according to one embodiment, a CU (110) of a virtual wireless access network (100) can be implemented as a virtualized vCU (virtualized-CU), and at least one DU (130_1, ..., 130_2) can be implemented as a virtualized vDU (virtualized-DU). When the CU (110) and at least one DU (130_1, ..., 130_2) according to one embodiment are implemented as a vCU and a vDU, the CU (110) and at least one DU (130_1, ..., 130_2) do not operate as physical hardware devices, but can perform the functions of the CU and DU as software modules.

[0066] In one embodiment, when at least one DU (130_1, ..., 130_2) is implemented as a vDU, a vDU pooling technology can be applied to at least one DU (130_1, ..., 130_2). The vDU pooling technology can reduce the number of servers required to build a RAN system by breaking the 1:1 matching relationship between a non-virtualized DU and a Cell (or a set of RUs) and pooling and virtualizing the DU. Therefore, the vDU pooling technology can reduce CAPEX (capital expenditure) and OPEX (operational expenditure) by reducing power consumption.

[0067] In a similar manner to implementing at least one DU (130_1, ..., 130_2) as a vDU, the CU (110) can also be implemented as a vCU, and by implementing the CU (110) as a vCU, CAPEX reduction and OPEX reduction effects can be obtained.

[0068] Here, the term "virtualization" can refer to a technology that can expand the resources available on a single device by integrating and managing multiple physical resources.

[0069] For convenience of explanation, the present disclosure assumes that CU (110) and at least one DU (130_1, ..., 130_2) are implemented as virtualized vCU and vDU for vRAN. However, the present disclosure is not limited thereto. For example, in a virtual radio access network (100) according to one embodiment, only at least one DU (130_1, ..., 130_2) may be implemented as a virtualized vDU, and the CU (110) may not be virtualized.

[0070] In the present disclosure, for the convenience of explanation, the number of RUs connected to a DU of a virtual wireless access network (100) or the number of UEs connected to the RUs is described as being constant, but is not limited thereto. For example, the number of RUs connected to DU 1 (130_1) and the number of RUs connected to DU N (130_2) may be different from each other, and the number of UEs connected to RU 1 (140_1) and the number of UEs connected to RU M (140_2) may be different from each other.

[0071] According to one embodiment, the OAM (120, Operations, Administration, and Maintenance) may be connected to each unit including the CU and RU of the virtual radio access network (100) and control the operation of each unit. For example, the OAM (120) may control DU 1 (130_1) to change the MAC (medium access control) address of DU 1 (130_1), or control DU 1 (130_1) to transmit data to at least one RU among a plurality of RUs (140_1, ..., 140_2) or not to transmit data.

[0072] An OAM (120) according to one embodiment may refer to a set of functions and protocols that support network operation, management, and maintenance. For example, an OAM (120) may not directly correspond to a specific network element, but may include a concept that includes functions necessary for the operation and management of the entire network. Accordingly, an OAM (120) according to one embodiment may be implemented as a specific device, but may also be implemented in combination with at least one unit among a CU (110), at least one DU (130_1, ..., 130_2), and a plurality of RUs (140_1, ..., 140_4) within a virtual wireless access network (100). In addition, an OAM (120) according to one embodiment may be implemented as a program or module written in software of the virtual wireless access network (100).

[0073] In one embodiment of the present disclosure, the CU (110) may be an entity that performs the functions of some layers among the protocol layers of a network. For example, the CU (110) may be an entity that performs network functions of the RRC (radio resource control) layer and the PDCP (packet data convergence protocol) layer, but the functions that the CU (110) can process (or convert) are not limited to the functions of the RRC layer and the PDCP layer described above. For example, the CU (110) may perform functions such as setting QoS (quality of service), reordering packets, etc., setting security and processing (or converting).

[0074] According to one embodiment, DU 1 (130_1) may perform various wireless access network functions for signal processing (or conversion) by the functions of RLC (radio link control, 131) layer, MAC (133) layer, and PHY (physical layer, 135). In addition, a plurality of DUs including DU N (130_2) according to one embodiment may include layers having the same configuration as DU 1 (130_1). Hereinafter, the term 'RLC' may refer to an entity that performs at least some of the functions of an 'RLC layer' or an RLC layer. The term 'MAC' may refer to an entity that performs at least some of the functions of a 'MAC layer' or a MAC layer. The term 'PHY' may refer to an entity that performs at least some of the functions of a 'PHY layer' or a PHY layer.

[0075] An RLC (131) according to one embodiment may include at least some of the following functions.

[0076] - Transfer of upper layer PDUs (protocol data units)

[0077] - In-sequence delivery of upper layer PDUs

[0078] - Out-of-sequence delivery of upper layer PDUs

[0079] - Error correction function through ARQ (automatic repeat request)

[0080] - Concatenation, segmentation, and reassembly of RLC SDUs (service data units)

[0081] - Re-segmentation of RLC data

[0082] - Reordering of RLC data

[0083] - Duplicate detection function

[0084] - Protocol error detection

[0085] - RLC SDU discard function

[0086] - RLC re-establishment function

[0087] The in-sequence delivery function of the RLC(131) layer refers to the function of sequentially delivering RLC SDUs (service data units) received from a lower layer to an upper layer, and may include a function of reassembling and delivering a single RLC SDU that is received divided into multiple RLC SDUs. In addition, the in-sequence delivery function may include at least one of a function of rearranging received RLC PDUs based on an RLC SN (sequence number) or a PDCP SN (sequence number), a function of recording lost RLC PDUs by rearranging the sequence, and a function of reporting the status of lost RLC PDUs to the transmitting side. In addition, the in-sequence delivery function may include a function of requesting retransmission of lost RLC PDUs, and, when there is a lost RLC SDU, a function of sequentially delivering only RLC SDUs up to the lost RLC SDU to an upper layer. Additionally, the in-order delivery function may include a function to sequentially deliver to the upper layer all RLC SDUs received before the timer starts if a predetermined timer has expired even if there are lost RLC SDUs, or a function to sequentially deliver to the upper layer all RLC SDUs received up to the present if a predetermined timer has expired even if there are lost RLC SDUs.

[0088] In one embodiment, an RLC PDU is used in RLC (131) and may include user data and may include a header and a data portion. The header of the RLC PDU may include information regarding transmission. For example, downlink data may be converted into the form of an RLC PDU in RLC (131).

[0089] According to one embodiment, the RLC (131) can process (or convert) RLC PDUs in the order in which they are received, regardless of the sequence order, and transmit them to the PDCP layer. When a segment is received, the RLC (131) can combine it with segments stored in the buffer or segments to be received later, reconstruct it into a complete RLC PDU, and then transmit the RLC PDU to the PDCP layer. Meanwhile, in NR (new radio), the RLC (131) may not include a concatenation function, and the concatenation function may be performed in the MAC (133) or replaced with a multiplexing function of the MAC (133).

[0090] According to one embodiment, RLC (131) can store UE context, store data in a retransmission buffer, and store data in a reception buffer.

[0091] The functions of the MAC (133) according to one embodiment may include at least some of the following functions.

[0092] - Mapping between logical channels and transport channels

[0093] - Multiplexing / demultiplexing of MAC SDUs

[0094] - Scheduling information reporting function

[0095] - Error correction through HARQ

[0096] - Priority handling between logical channels of one UE

[0097] - Priority handling between UEs by means of dynamic scheduling

[0098] - MBMS service identification function

[0099] - Transport format selection function

[0100] - Padding function

[0101] A PHY (135) according to one embodiment may perform at least some of the following functions.

[0102] - Data transmission and reception using electrical signals

[0103] - Channel coding / decoding function

[0104] - Modulation / demodulation function

[0105] - Power control

[0106] - Cell search

[0107] PHY (135) can perform channel coding and modulation on upper layer data, convert it into OFDM symbols, and transmit it over a wireless channel. In addition, PHY (135) can perform demodulation and channel decoding on OFDM symbols received over a wireless channel, and transmit the resulting data to a higher layer.

[0108] According to one embodiment, the PHY (135) may refer to a higher PHY (High-PHY) layer. The higher PHY layer may manage the upper PHY layer between the wireless base station and the terminal device, and perform data processing (or conversion), modem control, frequency spectrum management, etc. In this case, the lower PHY (Low-PHY) layer may exist in multiple RUs (140_1, ..., 140_4), and the functions of the PHY (135) may be performed in a divided manner.

[0109] FIG. 2a is a block diagram showing a scale-out situation of a DU according to one embodiment.

[0110] Referring to FIG. 2A, in a virtual wireless access network (100) according to one embodiment, an OAM (120) may receive information of each DU from at least one DU (130_1, ... , 130_2) and determine a scaling situation. For example, if the OAM (120) receives traffic information of DU N (130_2) from DU N (130_2) and determines that more resources are needed than the resources allocated to DU N (130_2), it determines that a scale-out situation exists, and creates DU N (130_2) as a source DU to which data will be transferred, and DU N+1 (130_3) as a target DU to which data will be transferred from the source DU, so that part or all of the data of DU N (130_2) may be transferred to DU N+1.

[0111] According to one embodiment, the operation of transferring data from DU N (130_2) to DU N+1 (130_3) may be divided into operations in which data is transferred from PHY (135_2) of DU N (130_2) to PHY (135_3) of DU N+1 (130_3) under the control of OAM (120), data is transferred from MAC (133_2) of DU N (130_2) to MAC (133_3) of DU N+1 (130_3), and data is transferred from RLC (131_2) of DU N (130_2) to RLC (131_3) of DU N+1 (130_3).

[0112] Additionally, according to one embodiment of the present disclosure, the operations of transferring data from the PHY (135_2) of DU N (130_2) to the PHY (135_3) of DU N+1 (130_3), transferring data from the MAC (133_2) of DU N (130_2) to the MAC (133_3) of DU N+1 (130_3), and transferring data from the RLC (131_2) of DU N (130_2) to the RLC (131_3) of DU N+1 (130_3) may be performed sequentially.

[0113] For example, first, data may be transferred from the PHY (135_2) of DU N (130_2) to the PHY (135_3) of DU N+1 (130_3), then data may be transferred from the MAC (133_2) of DU N (130_2) to the MAC (133_3) of DU N+1 (130_3), and then data may be transferred from the RLC (131_2) of DU N (130_2) to the RLC (131_3) of DU N+1 (130_3).

[0114] In this disclosure, it is assumed that data is transferred in the order of PHY, MAC, and RLC of the DU. However, this is not limited thereto.

[0115] In one embodiment, OAM (120) may change (or switch) the F1-U path receiving data from CU (110) from DU N (130_2) to DU N+1 (130_3) in a scale-out operation.

[0116] Once both the path change and data transfer are complete, the OAM (120) can determine that the scale-out operation is complete (or terminated).

[0117] FIG. 2b is a block diagram illustrating a scale-in situation of a DU according to one embodiment.

[0118] Referring to FIG. 2b, in a virtual wireless access network (100) according to one embodiment, an OAM (120) may receive information on each DU from at least one DU (130_1, ... , 130_2) and determine a scaling situation. For example, the OAM (120) may receive traffic information of DU N (130_2) from DU N (130_2), and if it is determined that DU N (130_2) requires fewer resources than a reference resource, determine that it is a scale-in situation, identify (or determine) DU N (130_2) as a source DU to which data will be transferred, and identify DU N-1 (130_4), which is a DU that processes relatively less traffic among the DU pool of the virtual wireless access network (100), as a target DU to which data will be transferred.

[0119] Additionally, some or all of the data of DU N(130_2) may be transferred to DU N-1(130_4).

[0120] When transferring part or all of the data of DU N(130_2) to DU N-1(130_4), the data of PHY(135_2), MAC(133_2), and RLC(131_2) of DU N(130_2) can be transferred to PHY(135_4), MAC(133_4), and RLC(131_4) of DU N-1(130_4), respectively, and the data transfer can proceed sequentially.

[0121] In one embodiment, OAM (120) may change (or switch) the F1-U path receiving data from CU (110) from DU N (130_2) to DU N-1 (130_4) in scale-in operation.

[0122] In one embodiment, when all data transfer from DU N (130_2) to DU N-1 (130_4) is completed, DU N (130_2), which no longer processes data, may be deleted (or removed) under the control of OAM (120). In one embodiment, when DU N (130_2) is deleted (or removed), OAM (120) may determine that the scale-in operation is complete.

[0123] According to one embodiment of the present disclosure, the action of 'deleting a DU' may include an action of no longer allocating memory or processors allocated to the DU being deleted, if the DU is a vDU.

[0124] In one embodiment, when both the DU N(130_2) path change and data transfer are completed, the OAM(120) may determine that the scale-out operation is complete (or terminated).

[0125] For convenience of explanation, the present disclosure describes the RLC transfer method of DU assuming a scale-out situation, as shown in Fig. 2a. However, this is not limited to this. For example, the RLC transfer method of DU described below can be equally applied to a scale-in situation.

[0126] Figure 3 illustrates an example of RLC transfer of a DU according to one embodiment.

[0127] Referring to FIG. 3, the RLC (310_1) of the first DU (300_1) may include data to be transferred, including a UE context, data stored in a retransmission buffer (313_1, ReTX buffer), and data stored in a reception buffer (315_1, Rx buffer). According to one embodiment, the first DU (300_1) may be a source DU to transfer data, and the second DU (300_2) may be a target DU to which data is to be transferred from the first DU (300_1).

[0128] According to one embodiment, the retransmission buffer (313_1) of the first DU (300_1) can temporarily store data requiring retransmission. In data communication between a terminal and a base station, data loss or errors may occur. In such cases, the first DU (300_1) can send the lost data by retransmitting the data in which the data loss or error occurred. For example, when data is stored in the retransmission buffer (313_1) and a retransmission request is received from the MAC (320_1), the requested data can be transmitted to the MAC (320_1).

[0129] According to one embodiment, the reception buffer (315) of the first DU (300_1) can store uplink data obtained from the MAC (320_1).

[0130] In the following, it is assumed that DU transfer is performed sequentially according to one embodiment of the present disclosure, and data transfer from the MAC (320_1) of the first DU (300_1) to the MAC (320_2) of the second DU (300_2) is completed. For example, RLC transfer is assumed.

[0131] In one embodiment, when RLC transfer is not performed, the downlink path through which downlink data is transferred is from the CU (110) to the RLC (310_1) of the first DU (300_1). For example, the RLC (310_1) of the first DU (300_1) may process (or convert) downlink data using the stored UE context (311_1) and transfer the processed (or converted) data to the MAC (320_2) of the second DU (300_2) for which MAC transfer has been completed.

[0132] Before RLC, while the UE context (311_1), data stored in the retransmission buffer (313_1) of the first DU (300_1), and data stored in the reception buffer (315_1) are transferred to the UE context (311_2), retransmission buffer (313_2), and reception buffer (315_2) of the second DU (300_2), uplink data transmission or downlink data transmission may be interrupted.

[0133] When the RLC transfer is completed, the downlink path through which the downlink data is transferred is from the CU (110) to the RLC (310_2) of the second DU (300_2). For example, the RLC (310_2) of the second DU (300_2) may process (or convert) the downlink data using the UE context (311_2) received and stored from the RLC (310_1) of the first DU, and may transfer the processed (or converted) data to the MAC (320_2) of the second DU (300_2) for which the MAC transfer is completed.

[0134] The above RLC transfer method has a problem in that data transfer is interrupted while RLC transfer is performed, and the time for which data transfer is interrupted may be long depending on the size of the buffer to be transferred.

[0135] Accordingly, the present disclosure proposes a method and an electronic device for performing RLC transfer by forwarding data without interrupting data transmission. According to one embodiment, the electronic device can forward data without interrupting data transmission and perform RLC transfer.

[0136] In the present disclosure, an electronic device may include all or part of a virtual radio access network configuration. For example, the electronic device may include an RLC transfer module (e.g., a scaling agent module) that manages, controls, or processes (or converts) RLC transfer. In one embodiment of the present disclosure, the electronic device performing the method (200) may include a device of a source DU, a device of a target DU, or another separate device. For example, the source DU (or the device of the source DU) may include an RLC transfer module. For example, the target DU (or the device of the target DU) may include an RLC transfer module. For example, another device separate from the source DU and the target DU may include an RLC transfer module.

[0137] FIG. 4 is a flowchart illustrating a method for performing RLC transfer of a DU according to one embodiment.

[0138] Referring to FIG. 4, a method (400) according to an embodiment of the present disclosure may include steps S410 to S460. In one embodiment of the present disclosure, steps S410 to S460 of the method (400) may be executed by an RLC transfer module included in an electronic device. In one embodiment of the present disclosure, steps S410 to S460 of the method (400) may be executed by at least one processor included in the electronic device. The method (400) is not limited to that illustrated in FIG. 4, and in one or more embodiments, steps not illustrated in FIG. 4 may be further included, or some steps may be omitted.

[0139] In step S410, the electronic device can identify (or determine, select, choose) a source RLC of a first DU to which data is to be transferred and a target RLC of a second DU to which data is to be transferred based on a scaling situation.

[0140] According to one embodiment, the scaling situation may be determined by the electronic device, or may be determined by another electronic device within the virtual wireless access network or an electronic device outside the virtual wireless access network (100) and transmitted to the electronic device. For example, when the electronic device determines the scaling situation, it may receive information about a plurality of DUs from a plurality of DUs of the virtual wireless access network (100) and determine the scaling situation. For example, the information about the DUs may include at least one of the amount of traffic processed (or converted) by the DU, CPU usage, and KPI.

[0141] In one embodiment, a scaling situation may include at least one of a scale-in situation and a scale-out situation, but is not limited thereto. For example, a scaling situation may further include a data migration-only situation, where only some data needs to be transferred, in addition to a scale-in or scale-out situation.

[0142] Additionally, an electronic device according to one embodiment of the present disclosure can identify a migrating user equipment (UE) of a source RLC, transfer the migrating UE context from the source RLC to the target RLC, and establish a radio bearer of the target RLC.

[0143] For example, the electronic device may identify a user device that a source RLC is processing (or converting) and may forward the UE context transferred from the source RLC to the target RLC so that the identified user device may be processed (or converted) at the target RLC. In one embodiment, the target RLC, having received the previous UE context, may establish a radio bearer for processing (or converting) and forwarding the data.

[0144] In step S420, an electronic device according to an embodiment of the present disclosure may transmit a data forwarding command from a source RLC to the target RLC to the source RLC.

[0145] For example, an electronic device may forward data to a target RLC, which is a previous target, and the target RLC, which receives the forwarded data, may process (or convert) the received data and transmit it to a MAC. Here, the electronic device according to one embodiment may include an OAM, and the OAM may transmit a forwarding command to the source RLC.

[0146] In step S430, the electronic device according to one embodiment may identify a downlink reference sequence number for downlink data obtained from the CU based on the forwarding command time point. Here, the electronic device according to one embodiment may include a source RLC.

[0147] In one embodiment, the electronic device may include a source DU, and the source DU may determine a reference sequence number for downlink data acquired from the CU at the time of receiving a forwarding command from the OAM. For example, if the sequence number of the downlink data was 85 at the time of receiving the forwarding command, the sequence number 85 may be identified (or determined, selected, chosen) as the downlink reference sequence number.

[0148] In step S440, the electronic device according to one embodiment may transmit downlink data processed (or converted) from one of the source RLC or the target RLC based on the downlink reference sequence number to the MAC of the second DU.

[0149] For example, the electronic device can identify which RLC processes (or converts) the downlink data based on the identified downlink reference sequence number, 85. For example, if the source RLC contains downlink data with sequence numbers 80 to 89, the electronic device can identify that the downlink data with sequence numbers 80 to 84 are processed (or converted) by the source RLC, and the downlink data with sequence numbers 85 to 89 are processed (or converted) by the target RLC. In this case, the source RLC can forward the downlink data with sequence numbers 85 to 89 to the target RLC.

[0150] In one embodiment of the present disclosure, the source RLC can process (or convert) downlink data with sequence numbers 80 to 84 and deliver them to the MAC of the second DU, and the target RLC can process (or convert) downlink data with sequence numbers 85 to 89 and deliver them to the MAC of the second DU.

[0151] In one embodiment of the present disclosure, the electronic device may update a first sequence number of data to be received from the CU of the target RLC after the forwarding command time point and a smallest second sequence number for which an acknowledgment (Ack) has not been received from the terminal based on the transmitted downlink reference sequence number information. In addition, according to one embodiment, the electronic device may set (or configure) a pollbit for the first downlink data transmitted through at least one radio bearer of the target DU.

[0152] In step S450, the electronic device according to one embodiment may transmit previous information of the source RLC to the target RLC.

[0153] The previous information of the source RLC according to one embodiment of the present disclosure may include at least one of cell index information, user equipment identification (UE ID) information, radio bearer index information, and the downlink reference sequence number information.

[0154] In step S460, the electronic device according to one embodiment can change the F1-U interface of the CU to the CU and the target RLC.

[0155] Before the RLC transfer is performed, the F1-U interface of the CU is connected to the RLC of the CU and the source DU, but after the RLC transfer is completed, the CU and the RLC of the target DU must be connected to send and receive data for the RLC transfer to be completed. Therefore, the electronic device can change (or update) the F1-U interface of the CU from the CU and the source RLC to the CU and the target RLC.

[0156] FIG. 5a is a block diagram illustrating a flow for transmitting downlink data before a UE context of RLC is transferred according to one embodiment.

[0157] Referring to FIG. 5A, the UE context (511_1) of the first DU (500_1) has not been transferred, and the F1-U interface of the CU (110) is also connected to the first DU (500_1). In addition, it is assumed that the MAC transfer from the MAC (520_1) of the first DU (500_1) to the MAC (520_2) of the second DU (500_2) has been completed. In this case, the path through which downlink data from the CU (110) is transferred to the second DU (500_2) is from the CU (110) to the first DU (500_1), and from the first DU (500_1) to the MAC (520_2) of the second DU (500_2).

[0158] According to one embodiment, during the process of transmitting downlink data, the RLC (510_1) of the first DU (500_1) may process (or convert) the downlink data using the UE context (511_1) and transmit the processed (or converted) downlink data to the MAC (520_2) of the second DU (500_2). For example, the downlink data may be an RLC Service Data Unit (SDU), and the downlink data processed (or converted) by the RLC (510_1) of the first DU (500_1) may be an RLC Protocol Data Unit (PDU).

[0159] An electronic device according to one embodiment of the present disclosure can identify a migrating user equipment (UE) of a source RLC, transfer the migrating UE context from the source RLC to the target RLC, and establish a radio bearer of the target RLC.

[0160] In one embodiment, all UEs connected to the cell being transferred may be transferred, and the transferred UEs may be transferred one by one rather than all at once. For example, if the UEs being transferred are UE1, UE2, and UE3, the context of UE1 may be transferred first, after completing the transfer of UE1, the context of UE2 may be transferred, after completing the transfer of UE2, the context of UE3 may be transferred, and then UE3 may be transferred.

[0161] FIG. 5b illustrates a flow for transmitting downlink data after a UE context of RLC is transferred according to one embodiment.

[0162] Referring to FIG. 5B, an electronic device according to an embodiment can transfer a UE context (511_1) of a first DU (500_1) to a UE context (511_2) of a second DU (500_2). Even after the UE context (511_1) of the first DU (500_1) is transferred to the UE context (511_2) of the second DU (500_2), downlink data is still transmitted from the CU (110) to the RLC (510_1) of the first DU (500_1) because the downlink path of the CU (110) or the interface of the F1-U has not changed.

[0163] According to one embodiment, when an electronic device transmits a data forwarding command to a first DU (500_1), the RLC (510_1) of the first DU (500_1) can identify a downlink reference sequence number based on the forwarding command timing, and identify (or determine, select, choose) downlink data to be forwarded to the RLC (510_2) of the second DU (500_2) among the downlink data transmitted from the CU (110) to the RLC (510_1) of the first DU (500_1) according to the identified sequence number.

[0164] In this case, the downlink path according to one embodiment is from the CU (110) to the RLC (510_1) of the first DU (500_1), from the RLC (510_1) of the first DU (500_1) to the RLC (510_2) of the second DU (500_2), and from the RLC (510_2) of the second DU (500_2) to the MAC (520) of the second DU (500_2). Additionally, according to one embodiment, the downlink data that is not forwarded may be delivered to the MAC (520) of the second DU (500_2) along the path of FIG. 5A.

[0165] An electronic device according to one embodiment can change (or update) the F1-U interface of the CU (110) from the RLC (510_1) of the CU (110) and the first DU (500_1) to the RLC (510_2) of the CU (110) and the second DU (500_2).

[0166] FIG. 5c illustrates a flow for transmitting downlink data after RLC transfer is completed according to one embodiment.

[0167] Referring to FIG. 5c, when the F1-U interface of the CU (110) is changed according to one embodiment and the RLC transfer is completed, downlink data is no longer processed (or converted) in the first DU (500_1).

[0168] In this case, the downlink path according to one embodiment is from the CU (110) to the RLC (510_2) of the second DU (500_2), and from the RLC (510_2) of the second DU (500_2) to the MAC (520) of the second DU (500_2).

[0169] FIG. 6 illustrates a flow for transferring UE context in a virtual wireless access network according to one embodiment.

[0170] Referring to FIG. 6, in step S610, according to one embodiment, the OAM (610) may identify (or determine, select, or choose) a UE to which data will be transferred. For example, the UE to be transferred may be a UE whose source RLC (630) of the first DU to which data is being transferred is processing (or converting).

[0171] According to one embodiment, the OAM (610) may request (S630) a UE context for an identified previous UE from the source RLC (630) of the first DU, receive (S630) the requested UE context from the source RLC (630) of the first DU, and transmit (S640) the UE context to the target RLC (640) of the second DU.

[0172] In addition, according to one embodiment, the OAM (610) commands the target RLC (640) of the second DU to set up a radio bearer (S650), and the target RLC (640) of the second DU can initialize the radio bearers of the UE by setting up the radio bearer.

[0173] FIG. 7 illustrates a flow of forwarding RLC data and transmitting data between a source RLC and a target RLC in a virtual wireless access network according to one embodiment.

[0174] Referring to FIG. 7, according to one embodiment, at step S710, the OAM (610) may command (or request) the source RLC (630) of the first DU to forward data. For example, step S710 may be performed after step S650 of FIG. 6.

[0175] The source RLC (630) of the first DU that received the data forwarding command in step S720 can determine the sequence number for the downlink data at the time of receiving the data forwarding command as the downlink reference sequence number.

[0176] In this disclosure, variables referring to sequence numbers are merely exemplary, and may be represented by variable names having the same function or meaning.

[0177] In one embodiment, the sequence number to be assigned to newly generated downlink data (e.g., UMD PDU) at the time of receiving a forwarding command may be determined as a downlink reference sequence number.

[0178] For example, the source RLC (630) of the first DU can identify downlink data having a sequence number smaller than the TX_Next value, which is a sequence number to be assigned to newly generated downlink data, as data to be processed (or converted) by the source RLC (630) of the first DU, and downlink data having a sequence number larger than the TX_Next value can be identified as data to be processed (or converted) by the target RLC (640) of the second DU.

[0179] The TX_Next value according to one embodiment may include a sequence number used to generate downlink data when the source RLC (630) of the first DU generates downlink data to be sent to the MAC. In addition, the TX_Next_Ack value according to one embodiment may mean the sequence number of the downlink data having the smallest sequence number for which an acknowledgment (Ack) has not been received from the UE. For example, the TX_Next_Ack value may mean the sequence number value of the next downlink data (e.g., RLC SDU) to be sequentially received.

[0180] In one embodiment, the TX_Next value may be a forwarding status variable, which may be a value for assigning a sequence number for newly generated downlink data following the downlink data (e.g., AMD PDU) generated so far. For example, the TX_Next value may be initially set to 0, and may be updated when the source RLC (630) of the first DU transmits downlink data whose sequence number is the TX_Next value. In one embodiment, the TX_Next_Ack may be an acknowledgment status variable, which may mean the next downlink sequence number value for which an ACK will be received in sequence. For example, the TX_Next_Ack value may be initially set to 0, and may be updated when the source RLC (630) of the first DU receives an ACK.

[0181] In the present disclosure, a sequence number to be assigned to newly generated downlink data is exemplarily referred to as TX_Next, but is not limited thereto. For example, the sequence number to be assigned to newly generated downlink data in LTE or 4G may be VT(S). In one embodiment, the VT(S) value may be initially set to 0, and may be updated when the source RLC (630) of 1 DU transmits downlink data whose sequence number is the VT(S) value. In the present disclosure, a sequence number of the next downlink data to be sequentially received is exemplarily referred to as TX_Next_Ack, but is not limited thereto. For example, a sequence number of the next downlink data to be sequentially received in LTE or 4G may be VT(A). In one embodiment, the VT(A) value may be initially set to 0, and may be updated when the source RLC (630) of the first DU receives an ACK.

[0182] In step S730, according to one embodiment, the source RLC (630) of the first DU may transmit previous information to the target RLC (640) of the second DU.

[0183] For example, the previous information may include at least one of cell index information, user equipment identification (UE ID) information, radio bearer index information, and downlink reference sequence number information.

[0184] According to one embodiment, the target RLC (640) of the second DU may store the transmitted previous information and update the Tx_Next value and the Tx_Next_Ack value of the target RLC (640) of the second DU using the acquired downlink reference sequence number.

[0185] In one embodiment, the target RLC (640) of the second DU may store the previously transmitted information and update the VT(A) value and the VT(S) value of the target RLC (640) of the second DU using the acquired downlink reference sequence number.

[0186] In step S740, according to an embodiment, the target RLC (640) of the second DU may set a pollbit for the radio bearer. This allows the electronic device to quickly receive an acknowledgment response (Ack or NACK) for the reception buffer of the source RLC (630) of the first DU, thereby quickly releasing the reception buffer.

[0187] In one embodiment, the target RLC (640) of the second DU may send a reception status message request including a positive acknowledgement (ACK) or negative acknowledgement (NACK) indicating that the downlink data has been completely received to the UE, wherein the method of requesting the reception status message may include a method of setting a pollbit.

[0188] In one embodiment, a pollbit may be set on downlink data transmitted via at least one radio bearer.

[0189] For example, a UE that has received downlink data with a pollbit set can check the downlink data stored in the buffer of the UE and generate an ACK or NACK indicating which downlink data up to which sequence number has been completely received and which downlink data corresponding to which sequence number has not been received, and transmit the ACK or NACK to the target RLC (640) of the second DU.

[0190] In one embodiment, when certain conditions such as the number of PDU transmissions and the size of the PDU transmissions are satisfied, the target RLC (640) of the second DU can set a pollbit for downlink data, and the UE can send a reception status message for the downlink data for which a pollbit is set when certain conditions such as a timer are satisfied.

[0191] Additionally, in one embodiment, even if the above condition is not satisfied, the target RLC (640) of the second DU can set a pollbit for downlink data, and the UE can send a reception status message for the downlink data for which the pollbit is set.

[0192] Accordingly, various effects can be achieved, including the effect of being able to perform RLC transfer of a DU without interruption in communication of the UE, since a quick acknowledgment response can be received from the UE in the RLC transfer of the DU according to one embodiment.

[0193] When downlink data is transmitted from the CU (620) to the source RLC (630) of the first DU in step S750, according to one embodiment, the source RLC (630) of the first DU can forward the downlink data to the target RLC (640) of the second DU (S760), and the target RLC of the second DU can process (or convert) the forwarded data (S770) and transmit the processed (or converted) data to the MAC (650) of the second DU (S780).

[0194] For example, data forwarded to the target RLC (640) of the second DU may be an RLC SDU, and data processed (or converted) from the target RLC (640) of the second DU may be an RLC PDU.

[0195] Figure 8 illustrates downlink data stored in a source RLC according to one embodiment.

[0196] Referring to FIG. 8, according to one embodiment, when the source RLC (630) of the first DU receives a data forwarding command from the OAM (610), a plurality of RLC SDUs (810, 820, 830, 840, 850) which are downlink data stored in the reception buffer (800) included in the source RLC (630) of the first DU are shown.

[0197] For example, RLC SDU1 (810) may have a sequence number of 81 and may have received a positive response from the UE, RLC SDU2 (820) may have a sequence number of 82 and may not have received a positive response from the UE, RLC SDU3 (830) may have a sequence number of 83 and may have received a positive response from the UE, RLC SDU4 (840) may have a sequence number of 84 and may not have received a positive response from the UE, and RLC SDU5 (850) may have a sequence number of 85 and may be downlink data not acquired from the CU (620).

[0198] For example, the downlink reference sequence number is 85, which is the TX_Next or VT(S) value, and RLC SDU 1 (810), RLC SDU 2 (820), RLC SDU 3 (830), and RLC SDU 4 (840) having sequence numbers smaller than the TX_Next or VT(S) value may be processed (or converted) and retransmission managed in the source RLC (630) of the first DU. Additionally, RLC SDU 5 (850) having sequence numbers larger than the TX_Next or VT(S) value according to one embodiment may be processed (or converted) and retransmission managed in the target RLC (640) of the second DU.

[0199] Here, the TX_Next_Ack and VT(A) values ​​may indicate the sequence number of the downlink data with the lowest sequence number for which no positive response has been received from the terminal. For example, the TX_Next_Ack and / or VT(A) values ​​may be used to manage downlink data retransmitted to the UE.

[0200] When the source RLC (630) of the first DU receives a positive acknowledgement from the UE and TX_Next_Ack or VT(A) is updated so that TX_Next_Ack=Tx_Next or VT(S)=VT(A), i.e., when there is no more downlink data to be retransmitted (or converted) in the receive buffer (800), the source RLC (630) of the first DU can release the receive buffer.

[0201] Figure 9 illustrates a flow for changing the F1-U path of a CU in a virtual wireless access network in one embodiment.

[0202] Referring to FIG. 9, in step S910, an OAM (610) according to an embodiment may instruct a CU (620) to change (or update) the F1-U path to the target RLC of the second DU. For example, step S910 may be performed after step S740 of FIG. 7.

[0203] When the path of F1-U of CU (620) is changed in step S910, according to one embodiment, CU (620) can transmit downlink data to target RLC (640) of second DU (S920), and target RLC (640) of second DU can process (or convert) the transmitted downlink data (S930) and transmit the processed (or converted) data to MAC (650) of second DU (S940).

[0204] FIG. 10 illustrates a method for performing RLC transfer of DU for uplink data in a virtual wireless access network according to one embodiment.

[0205] In FIG. 10, a method is described in which an electronic device identifies an uplink reference sequence number and processes (or converts) uplink data according to an RLC transfer by transmitting the uplink reference sequence number.

[0206] Referring to FIG. 10, an operating method of an electronic device according to one embodiment may include steps S1010 to S1060. In one embodiment of the present disclosure, steps S1010 to S1060 may be executed by at least one processor included in the electronic device. The operating method of the electronic device is not limited to that illustrated in FIG. 10, and in one or more embodiments, steps not illustrated in FIG. 10 may be further included, or some steps may be omitted.

[0207] Additionally, in one embodiment, the electronic device may control the operation of the OAM, the CU, the source RLC of the first DU, the target RLC of the second DU, and the MAC of the second DU to command the operation of each configuration to be performed.

[0208] In one embodiment of the present disclosure, in step S1010, the electronic device can identify a source RLC of a first DU to which data is to be transferred and a target RLC of a second DU to which data is to be transferred based on a scaling situation.

[0209] According to one embodiment, the scaling situation may be determined by the electronic device, or may be determined by another electronic device within the virtual wireless access network or an electronic device outside the virtual wireless access network (100) and transmitted to the electronic device. For example, when the electronic device determines the scaling situation, it may receive information about a plurality of DUs from a plurality of DUs of the virtual wireless access network (100) and determine the scaling situation. For example, the information about the DUs may include at least one of the amount of traffic processed (or converted) by the DU, CPU usage, and KPI.

[0210] In one embodiment, a scaling situation may include at least one of a scale-in situation and a scale-out situation, but is not limited thereto. For example, a scaling situation may further include a data migration-only situation, where only some data needs to be transferred, in addition to a scale-in or scale-out situation.

[0211] Additionally, an electronic device according to one embodiment of the present disclosure can identify a migrating user equipment (UE) of a source RLC, transfer the migrating UE context from the source RLC to the target RLC, and establish a radio bearer of the target RLC.

[0212] For example, the electronic device may identify the UE that the source RLC is processing (or converting) and may transfer the UE context transferred from the source RLC to the target RLC so that the identified UE can be transferred to the target RLC. In one embodiment, the target RLC, which has received the transferred UE context, may establish a radio bearer for processing (or converting) and forwarding the data.

[0213] In step S1020, an electronic device according to an embodiment of the present disclosure may transmit a data forwarding command from a source RLC to a target RLC to the source RLC.

[0214] For example, an electronic device may forward data to a target RLC, which is a previous target, and the target RLC, which receives the forwarded data, may process (or convert) the received data and transmit it to a MAC. Here, the electronic device according to one embodiment may include an OAM, and the OAM may transmit a forwarding command to the source RLC.

[0215] In step S1030, the electronic device according to one embodiment of the present disclosure can identify an uplink reference sequence number for uplink data obtained from the MAC of the second DU based on the forwarding command time point.

[0216] In one embodiment, the uplink reference sequence number may indicate a sequence number of uplink data that has not yet been completely delivered and for which a timer has not expired among the uplink data of the source RLC (630) of the first DU. For example, the uplink reference sequence number may be the RX_Highest_Status value, which is the sequence number of uplink data that has not yet been completely delivered and for which a timer has not expired among the uplink data of the source RLC at the time of the forwarding command.

[0217] Here, the timer according to one embodiment may represent a t-Reamssembly timer.

[0218] In one embodiment, RX_Highest_Status may indicate uplink data that has not yet been completely delivered and for which the timer has not expired among the uplink data of the source RLC (630) of the first DU. In one embodiment, the sequence number of the uplink data that has not yet been completely delivered and for which the timer has not expired among the uplink data may be VR(MS).

[0219] In one embodiment, the sequence number following the last fully received uplink data (e.g., AMD PDU) may be represented as RX_Next. For example, the RX_Next value may represent a receive status variable, and the RX_Next value may represent the sequence number following the last fully received RLC SDU in the sequence. For example, the RX_Next value may be initially set to 0 and may be incremented and updated by 1 each time the source RLC (630) of the first DU receives uplink data whose sequence number is the RX_Next value.

[0220] Additionally, the sequence number following the last fully received uplink data (e.g., AMD PDU) may be represented as VR(R).

[0221] In one embodiment, the source RLC (630) of the first DU can identify a fourth sequence number of uplink data for which a timer has expired and which has not been completely transmitted among the uplink data of the source RLC (630) of the first DU and a fifth sequence number which is a highest sequence number among the uplink data of the source RLC (630). For example, the fourth sequence number can be an RX_Next or VR(R) value, and the fifth sequence number can be an RX_Next_Highest or VR(H) value.

[0222] In one embodiment, the electronic device may transmit an ACK message or a NACK message for uplink data based on the third sequence number, the fourth sequence number, and the fifth sequence number.

[0223] For example, the electronic device can quickly release the contents of the reception buffer by transmitting an ACK message to the MAC for uplink data from the fourth sequence number to the fifth sequence number, which is data to be processed (or converted) by the source RLC (630) of the first DU based on the third sequence number, which is the uplink reference sequence number.

[0224] In one embodiment, the uplink data in the reception buffer of the source RLC to be transferred from the source RLC to the target RLC may be uplink data having a sequence number greater than the uplink reference sequence number RX_Highest_Status or VR(MS) and less than RX_Next_Highest or VR(H). These uplink data may be transferred to the target RLC in the same format as the uplink data transferred from the MAC. Accordingly, the source RLC according to the present disclosure may transmit only a portion of the uplink data in the reception buffer to the target RLC without having to transmit the uplink data stored in the entire buffer, thereby reducing the RLC transfer time and various other effects including the effect of reducing the buffer size may occur.

[0225] Additionally, in one embodiment, the electronic device may update the RX_Next or VT(S) value to the RX_Highest_Status or VR(MS) value before generating an ACK message or NACK message and may ignore retransmission requests for uplink data prior to the unreceived uplink reference sequence number.

[0226] Uplink data that must transmit a NACK message smaller than RX_Hishgest_Status or VR(MS) are uplink data that have passed their normal transmission time. Therefore, when transmitting a NACK message, the RLC transfer time may increase for retransmission processing (or conversion). In one embodiment of the present disclosure, the source RLC may ignore uplink data smaller than RX_Hishgest_Status or VR(MS). Furthermore, in one embodiment, the ignored uplink data may be recovered through a retransmission mechanism in a higher layer.

[0227] In one embodiment of the present disclosure, the electronic device can forward uplink data transmitted from a MAC having a source RLC greater than an uplink reference sequence number to a target RLC.

[0228] In step S1040, the electronic device according to one embodiment of the present disclosure can transmit previous information of the source RLC to the target RLC.

[0229] In one embodiment, the previous information of the source RLC may include at least one of cell index information, user equipment identification (UE ID) information, radio bearer index information, and the downlink reference sequence number information.

[0230] In step S1050, an electronic device according to an embodiment of the present disclosure may transfer (or transmit, transmit) uplink data processed (or converted) from one of a source RLC or a target RLC to the CU based on an uplink reference sequence number.

[0231] In one embodiment, when an electronic device receives a data forwarding request which is an uplink reference sequence number, the electronic device can identify (or determine, select, or elect) uplink data having a sequence number greater than or equal to the uplink reference sequence number to be processed (or converted) at the target RLC based on the RX_Highest_Status or VR(MS) value, and can identify (or determine, select, or elect) uplink data having a sequence number less than the uplink reference sequence number to be processed (or converted) at the source RLC. In one embodiment, the uplink data processed (or converted) from each of the source RLC or the target RLC can be delivered (or transmitted, or transmitted) to the CU.

[0232] In step S1060, the electronic device according to one embodiment of the present disclosure can change the path between the MAC and the source RLC to the path between the MAC and the target RLC.

[0233] For example, the electronic device can change the MAC-RLC path used for RLC PDU transmission in the MAC direction from the source RLC to the target RLC direction and complete the transfer of uplink data.

[0234] In this case, since no uplink data is received from the source RLC, resources required for uplink data processing (or conversion) can be released.

[0235] FIG. 11a is a block diagram illustrating a flow for transmitting uplink data before RLC transfer according to one embodiment.

[0236] Referring to FIG. 11a, in one embodiment, a MAC transfer from the MAC (520_1) of the first DU (500_1) to the MAC (520_2) of the second DU (500_2) may be completed before an RLC transfer from the RLC (510_1) of the first DU (500_1) to the RLC (510_2) of the second DU (500_2). In the following description, it is assumed that the RLC transfer is performed after the MAC transfer is completed.

[0237] In one embodiment, before the RLC transfer, the MAC (520_2) of the second DU (500_2) can transfer the uplink data of the UE to the RLC (510_2) of the first DU (500_1), and the RLC (510_2) of the first DU (500_1) can store and process (or convert) the transferred uplink data in a reception buffer (513_1) and transfer the processed (or converted) uplink data to the CU (110).

[0238] Figure 11b illustrates a flow for transmitting uplink data when RLC is transferred according to one embodiment.

[0239] Referring to FIG. 11B, in one embodiment, the RLC (510_1) of the first DU (500_1) may receive an uplink data forwarding command from the OAM and identify (or determine, select, choose) an uplink reference sequence number. In one embodiment, the RLC (510_1) of the first DU (500_1) may identify (or determine, select, choose) uplink data to be processed (or converted) in the RLC (510_1) of the first DU (500_1) or the RLC (510_2) of the second DU (500_2) based on the identified uplink reference sequence number.

[0240] In one embodiment, the uplink data may represent an RLC SDU, and the uplink data processed (or converted) by the RLC (510_1) of each first DU (500_1) and the RLC (510_2) of each second DU (500_2) and transmitted to the CU may be an RLC PDU.

[0241] In one embodiment, the RLC (510_1) of the first DU (500_1), which has received uplink data from the MAC (520_2) of the second DU (500_2), may store the received uplink data in the form of an RLC SDU in the reception buffer (515_1) and forward it to the RLC (510_2) of the second DU (500_2). For example, the uplink data in the reception buffer of the source RLC to be transferred from the source RLC to the target RLC may be uplink data whose sequence number is greater than the uplink reference sequence number RX_Highest_Status or VR(MS) and less than RX_Next_Highest or VR(H). Such uplink data may be transmitted to the target RLC in the same form as the uplink data transmitted from the MAC. Accordingly, the source RLC according to the present disclosure transmits only a portion of the uplink data within the reception buffer to the target RLC, thereby eliminating the need to transmit the uplink data stored in the entire buffer, thereby resulting in various effects including shortening the RLC transfer time and reducing the buffer size.

[0242] In one embodiment, the RLC (510_2) of the second DU (500_2) may store uplink data received from the reception buffer (515_1) of the first DU (500_1) in the form of an RLC SDU in the reception buffer (515_2) of the second DU (500_2) and process (or convert) the stored RLC SDU into an RLC PDU. In addition, in one embodiment, the RLC (510_2) of the second DU (500_2) may transfer (or transmit, transmit) the processed RLC PDU to the CU (110).

[0243] Figure 11c illustrates a flow for transmitting uplink data after RLC transfer is completed according to one embodiment.

[0244] Referring to FIG. 11c, when the RLC transfer according to one embodiment is completed, the MAC (520_2) of the second DU (500_2) can directly transfer (or transmit, send) uplink data to the RLC (510_2) of the second DU (500_2) by changing the path of the MAC-DU.

[0245] In one embodiment, the RLC (510_2) of the second DU (500_2) may store the received uplink data in a reception buffer (515_2) for an acknowledgment response, and process the uplink data for which transmission is completed to transmit (or transfer, transmit) to the CU (110).

[0246] Figure 12 illustrates a flow for transmitting uplink data during RLC transfer according to one embodiment.

[0247] Referring to FIG. 12, in step S1210, an OAM (610) according to one embodiment may command (or request) the source RLC (630) of the first DU to forward data. For example, step S1210 may be performed after step S650 of FIG. 6.

[0248] The source RLC (630) of the first DU that received the data forwarding command in step S720 can determine the sequence number for the uplink data at the time of receiving the data forwarding command as the downlink reference sequence number.

[0249] In one embodiment, RX_Highest_Status or VR(MS) may indicate uplink data of the source RLC (630) of the first DU that has not yet been completely delivered without a timer expiring.

[0250] In one embodiment, the RX_Next or VR(R) value may indicate a receive status variable, and the RX_Next or VR(R) value may indicate a sequence number following the last completely received RLC SDU in the sequence. For example, the RX_Next or VR(R) value may be initially set to 0 and incremented and updated by 1 each time the source RLC (630) of the first DU receives uplink data whose sequence number is the RX_Next or VR(R) value.

[0251] In one embodiment, the source RLC (630) of the first DU can identify a fourth sequence number of uplink data for which a timer has expired and which has not been completely transmitted among the uplink data of the source RLC (630) of the first DU and a fifth sequence number which is the highest sequence number among the uplink data of the source RLC (630). For example, the fourth sequence number can be an RX_Next or VR(R) value, and the fifth sequence number can be an RX_Next_Highest or VR(H) value.

[0252] In one embodiment, the source RLC (630) of the first DU may transmit an ACK message or a NACK message for uplink data based on the third sequence number, the fourth sequence number, and the fifth sequence number.

[0253] For example, the source RLC (630) of the first DU can quickly release the contents of the reception buffer by transmitting an ACK message to the MAC for uplink data from the fourth sequence number to the fifth sequence number, which is data to be processed (or converted) by the source RLC (630) of the first DU, based on the third sequence number, which is the uplink reference sequence number.

[0254] In step S1230, the source RLC (630) of the first DU according to one embodiment may transmit previous information to the target RLC (640) of the second DU.

[0255] For example, the previous information may include at least one of cell index information, user equipment identification (UE ID) information, radio bearer index information, and downlink reference sequence number information.

[0256] In step S1230, the source RLC (630) of the first DU according to one embodiment may transmit (or transmit, send) a retransmission request message including an ACK or NACK for the stored uplink data to the MAC (650) of the second DU. For example, the retransmission message may be a STATUS PDU.

[0257] In step S1250, the source RLC (630) of the first DU according to one implementation can identify (or determine, select, choose) uplink data to be processed in the source RLC (630) of the first DU and the target RLC (640) of the second DU based on the sequence number determined in step S1220, and forward the uplink data to be processed in the target RLC (640) of the second DU.

[0258] In step S1260, the target RLC (640) of the second DU according to one embodiment may process the uplink data based on the forwarded uplink data, if the uplink data is completely received, and transfer (or transmit, transmit) the processed uplink data to the CU (620).

[0259] For example, the forwarded uplink data may be an RLC PDU, and the uplink data processed by the target RLC (640) of the second DU may be an RLC SDU. The RLC PDU is a form in which an RLC header is combined with an RLC SDU, and the target RLC (640) of the second DU according to one embodiment may transmit an RLC SDU obtained from a MAC and having the RLC header removed to the CU.

[0260] Additionally, in one embodiment, if the target RLC (640) of the second DU has not completely received the forwarded uplink data, the target RLC (640) of the second DU may store the data in the reception buffer of the target RLC (640) of the second DU.

[0261] In step S1270, the MAC (650) of the second DU according to one embodiment may transfer (or transmit, transmit) uplink data requested from the source RLC (630) of the first DU to the source RLC (630) of the first DU. In step S1280, the source RLC (630) of the first DU according to one embodiment may transfer uplink data received from the MAC (650) of the second DU to the target RLC (640) of the second DU.

[0262] In step S1290, the target RLC (640) of the second DU according to one embodiment may process the uplink data forwarded in step S1280, if the uplink data is completely received, and transfer (or transmit, transmit) the processed uplink data to the CU (620).

[0263] Additionally, in one embodiment, if the target RLC (640) of the second DU has not completely received the forwarded uplink data, the target RLC (640) of the second DU may store the data in the reception buffer of the target RLC (640) of the second DU.

[0264] Figure 13 illustrates uplink data stored in a buffer of a source RLC according to one embodiment.

[0265] Referring to FIG. 13, in one embodiment, a buffer (1300) of a source RLC may store multiple AMD PDUs (1310, 1320, 1330, 1340, 1350, and 1360).

[0266] Here, AMD PDU may be uplink data received from MAC.

[0267] In one embodiment, at the point when the source RLC receives a data forwarding command from the OAM, the source RLC may identify (or determine, select, choose) the RX_Highest_Status or VR(MS) value as the uplink reference sequence number.

[0268] In one embodiment, RX_Highest_Status or VR(MS) may indicate uplink data from a source RLC that has not yet been completely delivered without a timer expiring.

[0269] In one embodiment, the source RLC can identify an RX_Next or VR(R) value and an RX_Next_Highest or VR(H) value. For example, the RX_Next or VR(R) value may indicate the fourth sequence number of uplink data whose timer has expired and has not been completely delivered among the uplink data of the source RLC, and the RX_Next_Highest or VR(H) value may be the fifth sequence number, which is the highest sequence number among the uplink data of the source RLC. The Rx_Highest_Status or VR(MS), RX_Next or VR(R), and RX_Next_Highest or VR(H) values ​​may be updated according to retransmitted data or timers.

[0270] For example, assume that AMD PDU 1 (1310) has a sequence number of 83 and all uplink data has been received, AMD PDU 2 (1320) has a sequence number of 84 and only some uplink data has been received, AMD PDU 3 (1330) has a sequence number of 85 and all uplink data has been received, AMD PDU 4 (1340) has a sequence number of 86 and only some uplink data has been received, AMD PDU 5 (1350) has a sequence number of 87 and only some uplink data has been received, and AMD PDU 6 (1360) has a sequence number of 88 and no uplink data has been received yet.

[0271] In this case, the RX_Next or VR(R) value may be 84, which is the sequence number of the uplink data whose timer has expired and has not been completely delivered among the uplink data of the source RLC, the RX_Highest_Status or VR(MS) value may be 86, and the RX_Next_Highest or VR(H) value may be 87.

[0272] In one embodiment of the present disclosure, the source RLC may determine that all uplink data, AMD PDU 1 (1310), which is uplink data having a sequence number less than the RX_Next or VR(R) value, has been received. In addition, in one embodiment, the source RLC may identify AMD PDU 2 (1320) and AMD PDU 3 (1330) as uplink data to be processed by the source RLC, and may send a retransmission request for AMD PDU 2 (1320) and AMD PDU 3 (1330) because a timer has expired. In one embodiment, AMD PDU 4 (1320) and AMD PDU 5 (1330) may not require a retransmission request as uplink data for which the timer has not yet expired, and may be identified as data to be processed by the target RLC. Therefore, the source RLC may forward AMD PDU 4 (1320) and AMD PDU 5 (1330) to the target RLC.

[0273] In one embodiment of the present disclosure, AMD PDU 6 (1360) having a sequence number greater than the RX_Next_Highest or VR(H) value may be identified as uplink data not yet acquired from the MAC.

[0274] Figure 14 illustrates a flow for changing a MAC-RLC path and transmitting uplink data according to one embodiment.

[0275] Referring to FIG. 14, in step S1410, the OAM (610) can command (or request) the MAC (650) of the target DU to change the MAC-RLC path from the RLC (630) of the source DU to the RLC (640) of the target DU, and the MAC (650) of the target DU can change the MAC-RLC path from the RLC (630) of the source DU to the RLC (640) of the target DU.

[0276] In step S1420, the MAC (650) of the target DU according to one embodiment can transmit uplink data to the RLC (640) of the target DU using the changed path.

[0277] In step S1430, the RLC (640) of the target DU according to one embodiment can identify whether the uplink data has been completely received, and if the uplink data has been completely received, can process the uplink data and transmit it to the CU (620). For example, if the uplink data has not been completely received, the RLC (640) of the target DU can store the uplink data transmitted in step S1420 and expect to receive additional uplink data.

[0278] FIG. 15 is a flowchart illustrating a method for transmitting a reception status message of a user device to a source RLC or a target RLC according to one embodiment.

[0279] Referring to FIG. 15, an operating method of an electronic device according to one embodiment may include steps S1510 to S1570. In one embodiment of the present disclosure, steps S1510 to S1570 may be executed by at least one processor included in the electronic device. The operating method of the electronic device is not limited to that illustrated in FIG. 15, and in one or more embodiments, steps not illustrated in FIG. 15 may be further included, or some steps may be omitted.

[0280] Additionally, in one embodiment, the electronic device may control the operation of the OAM, the CU, the source RLC of the first DU, the target RLC of the second DU, and the MAC of the second DU to command the operation of each configuration to be performed.

[0281] In step S1510, the electronic device according to one embodiment can identify a source RLC of a first DU to which data is to be transferred and a target RLC of a second DU to which data is to be transferred from the source RLC based on a scaling situation.

[0282] According to one embodiment, the scaling situation may be determined by the electronic device, or may be determined by another electronic device within the virtual wireless access network or an electronic device outside the virtual wireless access network (100) and transmitted to the electronic device. For example, when the electronic device determines the scaling situation, it may receive information about a plurality of DUs from a plurality of DUs of the virtual wireless access network (100) and determine the scaling situation. For example, the information about the DUs may include at least one of the amount of traffic processed (or converted) by the DU, CPU usage, and KPI.

[0283] In one embodiment, a scaling situation may include at least one of a scale-in situation and a scale-out situation, but is not limited thereto. For example, a scaling situation may further include a data migration-only situation, where only some data needs to be transferred, in addition to a scale-in or scale-out situation.

[0284] Additionally, an electronic device according to one embodiment of the present disclosure can identify a migrating user equipment (UE) of a source RLC, transfer the migrating UE context from the source RLC to the target RLC, and establish a radio bearer of the target RLC.

[0285] For example, the electronic device may identify the UE that the source RLC is processing (or converting) and may transfer the UE context transferred from the source RLC to the target RLC so that the identified UE can be transferred to the target RLC. In one embodiment, the target RLC, which has received the transferred UE context, may establish a radio bearer for processing (or converting) and forwarding the data.

[0286] In one embodiment, step S1510 may be performed after step S640 or step S650 of FIG. 6.

[0287] In step S1520, an electronic device according to one embodiment may issue a data forwarding command from a source RLC to a target RLC.

[0288] For example, an electronic device may forward data to a target RLC, which is a previous target, and the target RLC, which receives the forwarded data, may process (or convert) the received data and transmit it to a MAC. Here, the electronic device according to one embodiment may include an OAM, and the OAM may transmit a forwarding command to the source RLC.

[0289] In step S1530, the electronic device according to one embodiment can identify a sequence number for downlink data as a downlink reference sequence number based on a forwarding command point in time.

[0290] For example, the source RLC of the first DU can identify downlink data having a sequence number smaller than the TX_Next or VT(S) value based on the sequence number TX_Next or VT(S) value as data to be processed (or converted) by the source RLC of the first DU, and downlink data having a sequence number larger than the TX_Next or VT(S) value can be identified as data to be processed (or converted) by the target RLC of the second DU.

[0291] The TX_Next or VT(S) value according to one embodiment may include a sequence number used to generate downlink data when the source RLC of the first DU generates downlink data to be sent to the MAC. Additionally, the TX_Next_Ack or VT(A) value according to one embodiment may mean the sequence number of the downlink data having the smallest sequence number for which an acknowledgment (Ack) has not been received from the UE.

[0292] In one embodiment, the TX_Next or VT(S) value may be a forwarding status variable that assigns a sequence number for newly generated downlink data following the downlink data (e.g., AMD PDU) generated so far. For example, the TX_Next or VT(S) value may be initially set to 0 and may be updated when the source RLC (630) of the first DU transmits downlink data whose sequence number is the TX_Next or VT(S) value.

[0293] In one embodiment, TX_Next_Ack or VT(A) may be a recognition status variable indicating the next downlink sequence number value for which an ACK will be received in sequence. For example, the TX_Next_Ack or VT(A) value may be initially set to 0 and may be updated when the source RLC (630) of the first DU receives an ACK.

[0294] In step S1540, the electronic device according to one embodiment may transmit previous information of the source RLC to the target RLC.

[0295] For example, the previous information may include at least one of cell index information, user equipment identification (UE ID) information, radio bearer index information, and downlink reference sequence number information.

[0296] In step S1550, an electronic device according to one embodiment may obtain a reception status message including a positive response message or a negative response message for downlink data.

[0297] An electronic device according to one embodiment may obtain a reception status message of a UE from the MAC of a target DU. For example, the reception status of the UE may be a STATUS PDU.

[0298] In step S1560, the electronic device according to one embodiment may generate a first reception status message to be processed in the source RLC or a second reception status message to be processed in the target RLC based on the downlink reference sequence number and the reception status message.

[0299] Downlink data transmitted from a CU to a source DU or a target DU, and from a source DU or a target DU to a UE, is stored in the UE's receive buffer, so it is not known whether the reception status message for the generated downlink data will be processed by the source RLC or the target RLC. An electronic device according to one embodiment can consider both of these cases.

[0300] For example, when an electronic device receives a reception status message from a UE during an RLC transfer, the electronic device can divide the ACK or NACK information in the reception status message into information to be processed by the source RLC and information to be processed by the target RLC, and generate new reception status messages, namely, a first reception status message and a second reception status message, based on each piece of information.

[0301] In step S1570, the electronic device according to one embodiment may forward the first reception status message or the second reception status message to the source RLC or the target RLC.

[0302] In one embodiment, before the MAC-RLC path is changed to the target RLC, the electronic device can control the source RLC that generated the first reception status message and the second reception status message to process the first reception status message and forward the second reception status message to the target RLC.

[0303] In one embodiment, after the MAC-RLC path is changed to the target RLC, the electronic device can control the target RLC that generated the first reception status message and the second reception status message to forward the first reception status message to the source RLC, and control the target RLC to process the second reception status message.

[0304] In one embodiment of the present disclosure, when there is no more data for retransmission in the receive buffer of the source RLC, the electronic device may request the target RLC to stop forwarding the receive status signal, and the target RLC may recognize the termination of the previous RLC when it receives the request to stop forwarding from the source RLC.

[0305] For example, to determine whether there is no retransmission data in the receive buffer at the source RLC, the electronic device may determine that there is no retransmission data if the values ​​of TX_Next or VT(S) and TX_Next_Ack or VT(A) are equal.

[0306] FIG. 16a is a block diagram illustrating a path for processing a reception status message before an RLC-MAC path is changed according to one embodiment.

[0307] FIG. 16a illustrates an example of a data flow when data is being transferred from a UE context (511_1) and a reception buffer (515_1) of a first DU (500_1) to a UE context (511_2) and a reception buffer (515_2) of a second DU (500_2), but the MAC-DU path of the MAC (520_2) of the second DU (500_2) is not changed to the second DU (500_2), which is the target DU, according to one embodiment.

[0308] In Figure 16a, the solid line represents the uplink data path, the dotted line represents the downlink data path, and the dashed line represents the receive status message path.

[0309] Referring to FIG. 16A, a downlink data path according to one embodiment may be a case where the F1-U path of the CU (110) is changed to the RLC (510_2) of the second DU (500_2), and may be directed from the CU (110) to the RLC (510_2) of the second DU (500_2), and from the RLC (510_2) of the second DU (500_2) to the MAC (520_2) of the second DU (500_2). In this case, the UE context (511_1) of the first DU (500_2) may be transferred to the UE context (511_2) of the second DU (500_2) in the order of UEs identified.

[0310] According to one embodiment, an uplink data path may be directed from a MAC (520_2) of a second DU (500_2) to an RLC (510_1) of a first DU (500_1), and uplink data to be processed in the RLC (510_2) of the second DU (500_2) may be forwarded from the RLC (510_1) of the first DU (500_1) to the RLC (510_2) of the second DU (500_2), and the processed uplink data may be delivered to the CU (110).

[0311] According to one embodiment, the path of the reception status message of the UE may be from the MAC (520_2) of the second DU (500_2) to the RLC (510_1) of the first DU (500_1), and a first reception status message and a second reception status message may be generated based on the reception status message in the RLC (510_1) of the first DU (500_1), and the second reception status message may be transmitted to the RLC (510_2) of the second DU (500_2). Accordingly, data of the retransmission buffer (513_1) of the first DU (500_1) may not be transmitted to the retransmission buffer (513_2) of the second DU (500_2).

[0312] FIG. 16b is a block diagram showing a path for transmitting a reception status message after an RLC-MAC path is changed according to one embodiment.

[0313] Referring to FIG. 16b, since both the F1-U path and the RLC-MAC path have been changed to the RLC (510_2) of the second DU (500_2), the uplink data path and the downlink data path may exist between the CU (110), the RLC (510_2) of the second DU (500_2), and the MAC (520_2) of the second DU (500_2).

[0314] In one embodiment, even after the RLC-MAC path is changed to the RLC (510_2) of the second DU (500_2), the reception status message of the UE may still be processed in the RLC (510_1) of the first DU (500_1). Accordingly, the RLC (510_2) of the second DU (500_2) according to one embodiment may obtain the reception status message of the UE from the MAC (520_2) of the second DU (500_2), and generate a first reception status message to be processed in the RLC (510_1) of the first DU (500_1) and a second reception status message to be processed in the RLC (510_2) of the second DU (500_2), respectively. Additionally, the RLC (510_2) of the second DU (500_2) can forward the generated first reception status message to the RLC (510_1) of the first DU (500_1).

[0315] Figure 17 illustrates a flow for transmitting RLC transfer and reception status messages according to one embodiment.

[0316] Referring to FIG. 17, step S1710 may be performed after step S640 or step S650 of FIG. 6, and may also be performed after steps S1210 to S1230 of FIG. 12 are performed.

[0317] Below, it is assumed that steps S1210 to S1230 of FIG. 12 are performed.

[0318] In step S1710, the MAC (650) of the second DU according to one embodiment may transmit a reception status message of the UE for downlink data. For example, the reception status message of the UE may include a positive acknowledgement (ACK) message or a negative acknowledgement (NACK) message.

[0319] In step S1720, the source RLC (630) of the first DU can use the received reception status message of the UE to generate a first reception status message to be processed by the source RLC (630) of the first DU or a second reception status message to be processed by the target RLC (640) of the second DU based on the downlink reference sequence number.

[0320] For example, the source RLC (630) of the first DU may identify (or determine, decide) that downlink data corresponding to a reception status message having a sequence number smaller than a downlink reference sequence number will be processed by the source RLC (630) of the first DU, and may generate a first reception status message for the corresponding downlink data.

[0321] For example, the source RLC (630) of the first DU may identify (or determine, decide) that downlink data corresponding to a reception status message having a sequence number greater than or equal to a downlink reference sequence number will be processed by the target RLC (640) of the second DU, and may generate a second reception status message for the corresponding downlink data.

[0322] In step S1730, the source RLC (630) of the first DU according to one embodiment may forward a second reception status message, which is a reception status message for the target RLC, to the target RLC (640) of the second DU.

[0323] In step S1740, the OAM (610) according to one embodiment can request the MAC (650) of the second DU to change the MAC-RLC path from the source RLC (630) of the first DU to the target RLC (640) of the second DU, and the MAC (650) of the second DU can change the MAC-RLC path from the source RLC (630) of the first DU to the target RLC (640) of the second DU.

[0324] In step S1750, the MAC (650) of the second DU according to one embodiment may transmit the reception status message of the UE to the target RLC (640) of the second DU according to the changed MAC-RLC path.

[0325] In step S1770, the MAC (650) of the second DU according to one embodiment may use the received UE reception status message to generate a first reception status message to be processed by the source RLC (630) of the first DU or a second reception status message to be processed by the target RLC (640) of the second DU based on the downlink reference sequence number.

[0326] For example, the target RLC (630) of the second DU may identify (or determine, decide) that downlink data corresponding to a reception status message having a sequence number smaller than a downlink reference sequence number will be processed by the source RLC (630) of the first DU, and generate a first reception status message for the corresponding downlink data.

[0327] For example, the source RLC (630) of the second DU may identify (or determine, decide) that downlink data corresponding to a reception status message having a sequence number greater than or equal to a downlink reference sequence number will be processed by the target RLC (640) of the second DU, and generate a second reception status message for the corresponding downlink data.

[0328] In step S1770, the target RLC (640) of the second DU according to one embodiment may forward the first reception status message to be processed by the source RLC (630) of the first DU. Once the first reception status message is forwarded, the source RLC (630) of the first DU may perform retransmission of downlink data using the first reception status message.

[0329] Additionally, in one embodiment, the target RLC (640) of the second DU may perform retransmission of downlink data using the second reception status message.

[0330] In step S1780, the source RLC (630) of the first DU according to one embodiment may determine whether to stop forwarding the reception status message. For example, if there is no more data for retransmission in the reception buffer of the source RLC (630) of the first DU, the source RLC (630) of the first DU may request the target RLC (640) of the second DU to stop forwarding the reception status message, and if the target RLC (640) of the second DU receives a request to stop forwarding from the source RLC (630) of the first DU, the target RLC (640) of the second DU may recognize it as completion (or end) of the RLC transfer.

[0331] For example, to determine whether there is no retransmission data in the receiving buffer at the source RLC (630) of the first DU, the electronic device may determine that there is no retransmission data if the values ​​of TX_Next or VT(S) and TX_Next_Ack or VT(A) are the same.

[0332] In step S1790, the source RLC (630) of the first DU may request the target RLC (640) of the second DU to stop forwarding the reception status message.

[0333] For example, when the target RLC (640) of the second DU receives a request to stop forwarding a reception status message, it may determine that the entire RLC transfer is completed (or terminated) and stop forwarding the reception status message.

[0334] Figure 18 illustrates downlink data stored in user equipment according to one embodiment.

[0335] Referring to FIG. 18, in one embodiment, downlink data stored in a reception buffer (1800) of a UE may include downlink data having sequence numbers 77 to 100, and the first downlink data (1810), the fourth downlink data (1840), the sixth downlink data (1860), the eighth downlink data (1880), and the ninth downlink data (1890) may be completely received, and the second downlink data (1820), the third downlink data (1830), the fifth downlink data (1850), and the seventh downlink data (1870) may represent data that is partially received or not received and thus requires retransmission.

[0336] In one embodiment, based on the downlink data stored in the receive buffer (1800), the UE can generate a reception status message and transmit it to the MAC of the target DU.

[0337] FIG. 19 illustrates a reception status message to be processed by a source RLC and a target RLC, which are generated by dividing a reception status message according to one embodiment.

[0338] Referring to FIG. 19, a reception status message (1910) of a UE transmitted from a MAC according to an embodiment may include information about downlink data requiring retransmission of FIG. 18. For example, since NACK_SN=78 and NACK_range=3, from NACK_SN=85 to NACK_SN=87 and NACK_SN=98, the reception status message (1910) of the UE may include retransmission request information for the second downlink data (1820), the third downlink data (1830), the fifth downlink data (1850), and the seventh downlink data (1870) of FIG. 18.

[0339] For example, if the target RLC or the source RLC identifies the downlink reference sequence number as 87, the data to be processed by the source RLC may be downlink data having sequence numbers 78, 85, and 86, and the target RLC or the source RLC may generate a first reception status message (1930) to be processed by the source RLC. Additionally, if the target RLC or the source RLC identifies the downlink reference sequence number as 87, the data to be processed by the target RLC may be downlink data having sequence numbers 87, 98, and the target RLC or the source RLC may generate a second reception status message (1950) to be processed by the source RLC.

[0340] The operation of the electronic device described above can be applied not only when scaling DU, but also when only RLC is transferred without MAC transfer.

[0341] FIG. 20 is a block diagram illustrating an electronic device according to one embodiment.

[0342] The electronic device (2000) illustrated in FIG. 20 may be an electronic device that performs a previous operation for a DU. For example, the electronic device (1100) may be a server device. For example, the electronic device (2000) may be a communication device that constitutes a RAN. The electronic device (2000) may be a network device or server device that constitutes an existing RAN, such as a network device or server device that performs an RU function, a network device or server device that performs a DU function, a network device or server device that performs a CU function, or a network device or server device that performs an OAM function. The electronic device (2000) may be a separate network device or server device (e.g., a scale agent device) that controls cell transfer.

[0343] In one embodiment of the present disclosure, the electronic device (2000) may include, but is not limited to, a transceiver (2010), at least one processor (2020), and a memory (2030). The processor (2020) may be electrically connected to components included in the electronic device (2000) and may execute operations or data processing related to control and / or communication of the components included in the electronic device (2000). In one embodiment of the present disclosure, the processor (2020) may load and process requests, commands, or data received from at least one of the other components into a memory, and store the processing result data in the memory. According to various embodiments, the processor (2020) may include at least one of a general-purpose processor such as a central processing unit (CPU), an application processor (AP), a digital signal processor (DSP), a graphics-only processor such as a graphics processing unit (GPU), a vision processing unit (VPU), or an artificial intelligence-only processor such as a neural processing unit (NPU). In one embodiment, the processor (2020) may include at least one processing circuitry, such as a System-on-Chip (SoC) or an Integrated Circuit (IC).

[0344] The transceiver (2010) can support the establishment of a wired or wireless communication channel between the electronic device (2000) and another external electronic device and the performance of communication through the established communication channel.

[0345] According to one embodiment, the transceiver (2010) may receive data or data processing requests from other electronic devices or clients, or transmit generated data.

[0346] According to various embodiments, the transceiver (2010) may include a wireless communication module (e.g., a cellular communication module, a short-range wireless communication module, or a global navigation satellite system (GNSS) communication module) or a wired communication module (e.g., a local area network (LAN) communication module, or a power line communication module), and may communicate with an external electronic device through a short-range communication network (e.g., Bluetooth, WiFi direct, or IrDA (infrared data association)) or a long-range communication network (e.g., a cellular network, the Internet, or a computer network (e.g., a LAN or WAN)) using the corresponding communication module.

[0347] The processor (2020) may be controlled to process input data according to predefined operation rules, algorithms, methods, or models stored in the memory (2030). The processor (2020) may be controlled to process input data based on data stored in the memory (2030). The processor (2020) may perform operations of predefined operation rules, algorithms, methods, or models stored in the memory (2030) using the input data.

[0348] The memory (2030) is electrically connected to the processor (2020) and can store one or more modules, algorithms, operation rules, models, programs, commands, or data related to the operations of the components included in the electronic device (2000). For example, the memory (2030) can store one or more modules, algorithms, operation rules, models, programs, commands, or data for processing and controlling the processor (2020). The memory (2030) can include at least one type of storage medium among a flash memory type, a hard disk type, a multimedia card micro type, a card type memory (e.g., SD or XD memory, etc.), a RAM (Random Access Memory), a SRAM (Static Random Access Memory), a ROM (Read-Only Memory), an EEPROM (Electrically Erasable Programmable Read-Only Memory), a PROM (Programmable Read-Only Memory), a magnetic memory, a magnetic disk, and an optical disk, but is not limited thereto.

[0349] In one embodiment, the memory (2030) may store data or information identified, acquired, generated, or determined by the electronic device (2000). The memory (2030) may store data or information identified, acquired, generated, or determined by the electronic device (2000) in a compressed form. In one embodiment, the memory (2030) may include one or more storage media storing one or more instructions executable by the processor (2020). The one or more instructions, when individually or collectively executed by the processor (2020), may cause the electronic device (1000) to perform at least some of the operations described with reference to FIGS. 1 to 19.

[0350] Some modules that perform at least one operation of the electronic device (2000) may be implemented as hardware modules, software modules, and / or a combination thereof. The memory (2030) may include software modules that perform at least some of the operations of the electronic device (2000) described above. In one embodiment of the present disclosure, the modules included in the memory (2030) may perform operations by being executed by the processor (2020). For example, the modules (i.e., software modules) included in the memory (2030) may include programs, models, or algorithms that are executed according to the control or command of the processor (2020) and are configured to perform operations that derive output data for input data. Some modules that perform at least one operation of the electronic device (2000) may be configured as a plurality of sub-modules or may constitute a single module.

[0351] The electronic device (2000) may include more components than those illustrated in FIG. 20. In one embodiment of the present disclosure, the electronic device (2000) may further include a communication interface (or communication module) for communicating with an external device. In one embodiment of the present disclosure, the electronic device (2000) may further include an input / output device and / or an input / output interface.

[0352] In the present disclosure, overlapping descriptions in FIGS. 1 to 20 may be omitted, and one or more of the above-described embodiments may be applied / implemented in combination with each other. In the present disclosure, an operation described as being performed by a module may be executed / performed by an electronic device in which the module is included or stored, or may be executed / performed by the control of at least one processor of the electronic device in which the module is included. An operation described as being performed by an electronic device may be executed / performed by a module included or stored in the electronic device, or may be performed by the control of at least one processor of the electronic device using a module included or stored in the electronic device.

[0353] Although the embodiments described above have been described by way of limited examples and drawings, those skilled in the art will appreciate that various changes and modifications may be made based on the above description. For example, appropriate results may still be achieved if the described techniques are performed in a different order than described, and / or if components such as the described computer system or modules are combined or combined in a different manner than described, or if they are replaced or substituted with other components or equivalents.

[0354] In one embodiment of the present disclosure, a method for performing RLC (radio link control) migration of a wireless network system may include a step of identifying a source RLC of a first distributed unit (DU) to which data is to be migrated and a target RLC of a second DU to which data is to be migrated, based on a scaling situation. In one embodiment of the present disclosure, the method may include a step of transmitting a data forwarding command from the source RLC to the target RLC to the source RLC. In one embodiment of the present disclosure, the method may include a step of identifying a downlink reference sequence number for downlink data acquired from a centralized unit (CU) based on the forwarding command time point. In one embodiment of the present disclosure, the method may include a step of transmitting migration information of the source RLC to the target RLC. In one embodiment of the present disclosure, the method may include a step of transmitting the downlink data processed from one of the source RLC or the target RLC to a medium access control (MAC) of the second DU based on the downlink reference sequence number. In one embodiment of the present disclosure, the step of changing the F1-U interface of the CU to the CU and the target RLC may be included.

[0355] In one embodiment of the present disclosure, the scaling situation may include at least one of a scale in situation or a scale out situation.

[0356] In one embodiment of the present disclosure, the method may further include the steps of: identifying a user equipment (UE) to be migrated from the source RLC; transferring a context of the UE from the source RLC to the target RLC; and establishing a radio bearer of the target RLC.

[0357] In one embodiment of the present disclosure, the previous information may include at least one of cell index information, user equipment identification (UE ID) information, radio bearer index information, or information of the downlink reference sequence number.

[0358] In one embodiment of the present disclosure, the method may further include the steps of updating a first sequence number for newly generated downlink data of a target RLC based on the transmitted downlink reference sequence number information and a smallest second sequence number for downlink data for which an acknowledgment response (ACK) has not been received from the terminal; and the step of setting a pollbit to at least one radio bearer of the second DU.

[0359] In one embodiment of the present disclosure, the step of forwarding the downlink data processed from one of the source RLC or the target RLC to the MAC of the second DU may include, if the downlink data is downlink data having a sequence number greater than or equal to the downlink reference sequence number, forwarding the downlink data from the source RLC to the target RLC, forwarding the downlink data processed from the target RLC to the MAC of the second DU, and if the downlink data is downlink data having a sequence number less than the downlink reference sequence number, forwarding the downlink data processed from the source RLC to the MAC of the second DU.

[0360] In one embodiment of the present disclosure, the method further includes the steps of: identifying an uplink reference sequence number for uplink data obtained from the MAC of the second DU based on the forwarding command time point; transmitting the uplink data processed from one of the source RLC or the target RLC to the CU based on the uplink reference sequence number; and changing a path between the MAC and the source RLC to a path between the MAC and the target RLC, wherein the previous information may include the uplink reference sequence number.

[0361] In one embodiment of the present disclosure, the step of identifying the uplink reference sequence number may include a step of identifying a third sequence number of uplink data, among the uplink data of the source RLC, for which a timer has not expired and has not been completely delivered, as the uplink reference sequence number. In one embodiment of the present disclosure, the method may further include a step of identifying a fourth sequence number of uplink data, among the uplink data of the source RLC, for which a timer has expired and has not been completely delivered, and a fifth sequence number, which is a largest sequence number, among the uplink data of the source RLC; and a step of transmitting an acknowledgement (ACK) message or a negative acknowledgement (NACK) message for the uplink data based on the third sequence number, the fourth sequence number, and the fifth sequence number.

[0362] In one embodiment of the present disclosure, the step of transmitting a positive response message or a negative response message for the uplink data may include the step of transmitting a positive response message for the uplink data having a sequence number less than the fourth sequence number.

[0363] In one embodiment of the present disclosure, the method may further include the step of transferring uplink data having a sequence number greater than the third sequence number and less than the fourth sequence number stored in the buffer of the source RLC to the buffer of the target RLC.

[0364] In one embodiment of the present disclosure, the method may further include: obtaining a reception status message from the MAC, the reception status message including a positive acknowledgement (ACK) message or a negative acknowledgement (NACK) message for the downlink data received by the user device; generating a first reception status message to be processed by the source RLC or a second reception status message to be processed by the target RLC based on the downlink reference sequence number and the reception status message; and forwarding the first reception status message or the second reception status message to the source RLC or the target RLC.

[0365] In one embodiment of the present disclosure, the step of generating a first reception status message to be processed by the source RLC or a second reception status message to be processed by the target RLC based on the downlink reference sequence number and the reception status message may include the steps of generating the first reception status message to be processed by the source RLC using a reception status message for downlink data having a sequence number smaller than the downlink reference sequence number, and generating the second reception status message to be processed by the source RLC using a reception status message for downlink data having a sequence number greater than or equal to the downlink reference sequence number.

[0366] In one embodiment of the present disclosure, if the first sequence number for the newly generated downlink data of the target RLC is the same as the smallest second sequence number for the downlink data for which an acknowledgment (ACK) has not been received from the terminal based on the transmitted downlink reference sequence number information, the step of identifying that there is no downlink data to be retransmitted to the terminal may be further included.

[0367] In one embodiment of the present disclosure, an electronic device for performing RLC (radio link control) migration of a wireless network system may include a memory storing one or more instructions; and at least one processor for executing the one or more instructions stored in the memory. In one embodiment of the present disclosure, the at least one processor may, by executing the one or more instructions, cause the electronic device to identify a source RLC of a first distributed unit (DU) to which data is to be migrated and a target RLC of a second DU to which data is to be migrated from the source RLC, based on a scaling situation. In one embodiment of the present disclosure, the at least one processor may, by executing the one or more instructions, cause the electronic device to transmit a data forwarding command from the source RLC to the target RLC to the source RLC. In one embodiment of the present disclosure, the at least one processor may cause the electronic device to identify a downlink reference sequence number for downlink data obtained from a centralized unit (CU) based on the forwarding command time point by executing the one or more commands. In one embodiment of the present disclosure, the at least one processor may cause the electronic device to transfer previous information of the source RLC to the target RLC by executing the one or more commands. In one embodiment of the present disclosure, the at least one processor may cause the electronic device to transfer the downlink data processed from one of the source RLC or the target RLC based on the downlink reference sequence number to a MAC (medium access control) of the second DU by executing the one or more commands.In one embodiment of the present disclosure, the at least one processor may cause the electronic device to change the F1-U interface of the CU to the CU and the target RLC by executing the one or more instructions.

[0368] In one embodiment of the present disclosure, the scaling situation may include at least one of a scale in situation or a scale out situation.

[0369] In one embodiment of the present disclosure, the at least one processor may cause the electronic device to identify a user equipment (UE) to be migrated of the source RLC by executing the one or more instructions, transfer a context of the UE from the source RLC to the target RLC, and establish a radio bearer of the target RLC.

[0370] In one embodiment of the present disclosure, the previous information may include at least one of cell index information, user equipment identification (UE ID) information, radio bearer index information, or information of the downlink reference sequence number.

[0371] In one embodiment of the present disclosure, the at least one processor may cause the electronic device to update a first sequence number for newly generated downlink data of a target RLC and a smallest second sequence number for downlink data for which an acknowledgment (Ack) has not been received from a terminal based on the transmitted downlink reference sequence number information by executing the one or more instructions, and to set a pollbit for the downlink data to be transmitted through at least one radio bearer of the second DU.

[0372] In one embodiment of the present disclosure, the at least one processor may cause the electronic device to, by executing the one or more instructions, forward the downlink data from the source RLC to the target RLC if the downlink data is downlink data having a sequence number greater than or equal to the downlink reference sequence number, transmit the downlink data processed from the target RLC to the MAC of the second DU, and transmit the downlink data processed from the source RLC to the MAC of the second DU if the downlink data is downlink data having a sequence number less than the downlink reference sequence number.

[0373] In one embodiment of the present disclosure, the at least one processor may cause the electronic device to identify an uplink reference sequence number for uplink data obtained from the MAC of the second DU based on the forwarding command time point by executing the one or more instructions, and to transfer the uplink data processed from one of the source RLC or the target RLC based on the uplink reference sequence number to the CU, and to change a path between the MAC and the source RLC to a path between the MAC and the target RLC. The previous information may include the uplink reference sequence number.

[0374] In one embodiment of the present disclosure, the at least one processor may cause the electronic device to transfer uplink data having a sequence number greater than the third sequence number and less than the fourth sequence number stored in the buffer of the source RLC to the buffer of the target RLC by executing the one or more instructions.

[0375] In one embodiment of the present disclosure, the at least one processor may cause the electronic device to transmit a positive acknowledgement message for uplink data having a sequence number less than the fourth sequence number by executing the one or more instructions.

[0376] In one embodiment of the present disclosure, the at least one processor may cause the electronic device to obtain a reception status message including an acknowledgment (ACK) message or a negative acknowledgment (NACK) message for the downlink data received by the user device from the MAC by executing the one or more instructions, and generate a first reception status message to be processed by the source RLC or a second reception status message to be processed by the target RLC based on the downlink reference sequence number and the reception status message, and forward the first reception status message or the second reception status message to the source RLC or the target RLC.

[0377] In one embodiment of the present disclosure, the at least one processor may cause the electronic device to generate the first reception status message to be processed in the source RLC using a reception status message for downlink data having a sequence number less than the downlink reference sequence number by executing the one or more instructions, and to generate the second reception status message to be processed in the source RLC using a reception status message for downlink data having a sequence number greater than or equal to the downlink reference sequence number.

[0378] In one embodiment of the present disclosure, the at least one processor may cause the electronic device to identify that there is no downlink data to be retransmitted to the terminal when the first sequence number for the newly generated downlink data of the target RLC and the smallest second sequence number for the downlink data for which an acknowledgment (ACK) has not been received from the terminal are the same by executing the one or more instructions based on the transmitted downlink reference sequence number information.

[0379] A device-readable storage medium may be provided in the form of a non-transitory storage medium. Here, the term "non-transitory storage medium" simply means a tangible device that does not contain signals (e.g., electromagnetic waves). This term does not distinguish between cases where data is permanently stored in the storage medium and cases where data is temporarily stored. For example, a "non-transitory storage medium" may include a buffer in which data is temporarily stored.

[0380] According to one embodiment, the method according to various embodiments disclosed in the present document may be provided as included in a computer program product. The computer program product may be traded as a product between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read-only memory (CD-ROM)), or may be distributed online (e.g., downloaded or uploaded) through an application store or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product (e.g., a downloadable app) may be temporarily stored or temporarily generated in a machine-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or an intermediary server.

Claims

1. A method for performing RLC (radio link control) transfer of a wireless network system, A step (S410) of identifying a source RLC of a first DU (distributed unit) to which data is to be migrated and a target RLC of a second DU to which the data is to be migrated based on a scaling situation; A step (S420) of transmitting a data forwarding command from the source RLC to the target RLC to the source RLC; A step (S430) of identifying a downlink reference sequence number for downlink data acquired from a CU (centralized unit) based on the timing of the above data forwarding command; Step (S440) of transmitting previous information of the source RLC to the target RLC; Step (S450) of transmitting the downlink data processed from one of the source RLC or the target RLC based on the downlink reference sequence number to the MAC (medium access control) of the second DU; and A method comprising a step (S460) of changing the F1-U interface of the CU to the CU and the target RLC.

2. In paragraph 1, A method wherein the scaling situation includes at least one of a scale in situation or a scale out situation.

3. In paragraph 1 or 2, The above method, A step of identifying a user equipment (UE) to be migrated to the above source RLC; A step of transferring the context of the UE from the source RLC to the target RLC; and A method further comprising the step of setting up a radio bearer of the target RLC.

4. In any one of paragraphs 1 to 3, The above previous information, A method comprising at least one of cell index information, UE ID (user equipment identification) information, radio bearer index information, or information of the downlink reference sequence number.

5. In paragraph 4, The above method, A step of updating a first sequence number for downlink data to be generated in a target RLC based on the downlink reference sequence number information transmitted above and a smallest second sequence number for downlink data for which an acknowledgment (ACK) has not been received from a terminal; and A method further comprising the step of setting a pollbit in the downlink data to be transmitted through at least one radio bearer of the second DU.

6. In any one of paragraphs 1 to 5, The step of transmitting the downlink data processed from one of the source RLC or the target RLC to the MAC of the second DU is: If the downlink data is downlink data having a sequence number greater than or equal to the downlink reference sequence number, the downlink data is forwarded from the source RLC to the target RLC, and the downlink data processed from the target RLC is delivered to the MAC of the second DU. A method comprising the step of transmitting the downlink data processed from the source RLC to the MAC of the second DU when the downlink data is downlink data having a sequence number smaller than the downlink reference sequence number.

7. In any one of paragraphs 1 to 6, The above method, A step (S1030) of identifying an uplink reference sequence number for uplink data acquired from the MAC of the second DU based on the forwarding command time point; Step (S1050) of transmitting the uplink data processed from one of the source RLC or the target RLC to the CU based on the uplink reference sequence number; and In the above MAC, a step (S1060) of changing the path between the MAC and the source RLC to a path between the MAC and the target RLC is further included. A method wherein the above-mentioned previous information includes the uplink reference sequence number.

8. In paragraph 7, The step of identifying the above uplink reference sequence number is: Including a step of identifying a third sequence number of uplink data that has not been completely delivered and for which a timer has not expired among the uplink data of the source RLC as the uplink reference sequence number, The above method, A step of identifying a fourth sequence number of uplink data among the uplink data of the source RLC whose timer has expired and has not been completely transmitted and a fifth sequence number which is the largest sequence number among the uplink data of the source RLC; and A method further comprising the step of transmitting a positive acknowledgement (ACK) message or a negative acknowledgement (NACK) message for the uplink data based on the third sequence number, the fourth sequence number, and the fifth sequence number.

9. In paragraph 8, The step of transmitting a positive response message or a negative response message for the above uplink data is: A method comprising the step of transmitting a positive acknowledgement message for uplink data having a sequence number less than the fourth sequence number.

10. In clause 8 or 9, The above method, A method further comprising the step of transferring uplink data having a sequence number greater than the third sequence number and less than the fourth sequence number stored in the buffer of the source RLC to the buffer of the target RLC.

11. In any one of paragraphs 1 to 10, The above method, A step (S1150) of obtaining a reception status message including a positive acknowledgement (ACK) message or a negative acknowledgement (NACK) message for the downlink data received by the user device from the MAC; A step (S1560) of generating a first reception status message to be processed by the source RLC or a second reception status message to be processed by the target RLC based on the downlink reference sequence number and the reception status message; and A method further comprising a step (S1570) of forwarding the first reception status message or the second reception status message to the source RLC or the target RLC.

12. In paragraph 11, A step of generating a first reception status message to be processed by the source RLC or a second reception status message to be processed by the target RLC based on the downlink reference sequence number and the reception status message is as follows: A method comprising the steps of generating the first reception status message to be processed by the source RLC using a reception status message for downlink data having a sequence number less than the downlink reference sequence number, and generating the second reception status message to be processed by the source RLC using a reception status message for downlink data having a sequence number greater than or equal to the downlink reference sequence number.

13. In paragraph 11 or 12, A method further comprising the step of identifying that there is no downlink data to be retransmitted to the terminal if the first sequence number for the newly generated downlink data of the target RLC and the smallest second sequence number for the downlink data for which an acknowledgment (ACK) has not been received from the terminal are the same based on the downlink reference sequence number information transmitted above.

14. A non-transitory computer-readable storage medium having recorded thereon a program for performing the method of any one of claims 1 to 13 on a computer.

15. In an electronic device (2000) performing RLC (radio link control) transfer of a wireless network system, A memory (2030) storing one or more instructions; and At least one processor (2020) for executing one or more instructions stored in the memory, The at least one processor causes the electronic device to execute the one or more instructions, Based on the scaling situation, identify the source RLC of the first DU (distributed unit) to which data is to be migrated and the target RLC of the second DU to which the data is to be migrated from the source RLC, Transmitting a data forwarding command from the source RLC to the target RLC to the source RLC, Identify the downlink reference sequence number for downlink data acquired from the CU (centralized unit) based on the timing of the above forwarding command, Transfer the previous information of the above source RLC to the above target RLC, Transferring the downlink data processed from one of the source RLC or the target RLC based on the downlink reference sequence number to the MAC (medium access control) of the second DU, An electronic device that changes the F1-U interface of the above CU to the above CU and the target RLC.

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