Method and electronic device for performing radio link control layer transfer in wireless network system

Abstract

An operation method of an electronic device, according to one embodiment of the present disclosure, may comprise the steps of: identifying one or more user equipments (UEs) to be transferred from among a plurality of UEs associated with a target cell; configuring, in a radio link control (RLC) layer, control information about the one or more UEs to be transferred, configured in an RLC layer of a source distributed unit (DU); controlling that a centralized unit (CU) and / or a medium access control (MAC) layer of the target DU redundantly transmits a packet for the one or more UEs to be transferred to the RLC layer of the source DU and an RLC layer of the target DU; and removing information about the one or more UEs to be transferred from the RLC layer of the source DU.

Description

Method and electronic device for performing wireless link control layer transfer in a wireless network system

[0001] The present disclosure relates to a method and an electronic device for performing RLC (Radio Link Control) layer transfer in a wireless network system.

[0002] Looking back at the evolution of wireless communication over successive generations, technologies have primarily been developed for human-facing services such as voice, multimedia, and data. With the commercialization of 5G (5th-generation) communication systems, an explosive increase in connected devices is expected to be connected to communication networks. Examples of networked objects include vehicles, robots, drones, home appliances, displays, smart sensors installed in various infrastructures, construction equipment, and factory equipment. Mobile devices are expected to evolve into diverse form factors, including augmented reality glasses, virtual reality headsets, and holographic devices. In the 6th-generation (6G) era, efforts are being made to develop improved 6G communication systems to connect hundreds of billions of devices and objects and provide diverse services. For this reason, 6G communication systems are often referred to as "beyond 5G."

[0003] The 6G communication system, expected to be realized around 2030, will have a maximum transmission speed of terabytes per second (i.e., 1,000 gigabits per second) and a wireless latency of 100 microseconds (μsec). In other words, compared to 5G, the transmission speed in a 6G communication system will be 50 times faster, while the wireless latency will be reduced to one-tenth.

[0004] To achieve these high data rates and ultra-low latency, 6G communication systems are being considered for implementation in the terahertz band (e.g., from 95 gigahertz (GHz) to 3 terahertz (THz)). Compared to the millimeter wave (mmWave) band introduced in 5G, the terahertz band is expected to experience more severe path loss and atmospheric absorption, making it more crucial to ensure signal reach, or coverage, in this band. Key technologies to ensure coverage include radio frequency (RF) components, antennas, new waveforms that offer better coverage than OFDM (orthogonal frequency division multiplexing), beamforming, and multiple antenna transmission technologies such as massive multiple-input and multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas. In addition, new technologies such as metamaterial-based lenses and antennas, high-dimensional spatial multiplexing using orbital angular momentum (OAM), and reconfigurable intelligent surfaces (RIS) are being discussed to improve the coverage of terahertz band signals.

[0005] In addition, in order to improve frequency efficiency and system network, 6G communication systems are developing full duplex technology that utilizes the same frequency resources for uplink and downlink at the same time; network technology that integrates satellites and high-altitude platform stations (HAPS); network structure innovation technology that supports mobile base stations and enables optimization and automation of network operation; dynamic spectrum sharing technology through collision avoidance based on spectrum usage prediction; AI-based communication technology that utilizes artificial intelligence (AI) from the design stage and internalizes end-to-end AI support functions to realize system optimization; and next-generation distributed computing technology that realizes services with complexity that exceeds the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources (mobile edge computing (MEC), cloud, etc.). In addition, efforts are being made to further strengthen connectivity between devices, further optimize networks, promote softwareization of network entities, and increase the openness of wireless communications through the design of new protocols to be used in 6G communication systems, the implementation of hardware-based security environments, the development of mechanisms for the safe use of data, and the development of technologies for maintaining privacy.

[0006] Research and development of these 6G communication systems are expected to enable a new level of hyper-connected experience (the next hyper-connected experience) through the hyper-connectivity of 6G communication systems, which encompass not only connections between things but also connections between people and things. Specifically, 6G communication systems are expected to enable services such as truly immersive extended reality (Truly Immersive XR), high-fidelity mobile holograms, and digital replicas. Furthermore, services such as remote surgery, industrial automation, and emergency response, which are provided through 6G communication systems through enhanced security and reliability, will find application in diverse fields such as industry, medicine, automobiles, and home appliances.

[0007] In a radio access network (RAN) system, cell sites are connected to distributed units (DUs), and the processing (or conversion) capacity of the distributed units is determined by the maximum traffic that can enter the cell site. This leaves the DU's resources unused outside of peak traffic periods.

[0008] 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.

[0009] DUs and cell sites (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 breaks this 1:1 connection relationship, and by virtualizing through DU pooling, resources can be used efficiently and the number of servers can be reduced.

[0010] 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.

[0011] In one embodiment of the present disclosure, a method of operating an electronic device may include a step of identifying one or more transfer target UEs from among a plurality of UEs (User Equipment) associated with a target cell. In one embodiment of the present disclosure, the method of operating an electronic device may include a step of setting control information for the one or more transfer target UEs, which is set in an RLC layer of a source DU (Distributed Unit), to an RLC layer of a target DU. In one embodiment of the present disclosure, the method of operating an electronic device may include a step of controlling at least one of a Centralized Unit (CU) or a Medium Access Control (MAC) layer of the target DU to transmit packets for the one or more transfer target UEs to an RLC layer of the source DU and an RLC layer of the target DU in duplicate. In one embodiment of the present disclosure, the method of operating an electronic device may include a step of removing information for the one or more transfer target UEs from an RLC layer of the source DU.

[0012] In one embodiment of the present disclosure, a program for performing the above-described method on a computer can be recorded on a computer-readable recording medium.

[0013] In one embodiment of the present disclosure, an electronic device may include a memory that stores one or more instructions and at least one processor that executes one or more instructions. In one embodiment of the present disclosure, the electronic device may identify one or more transfer target UEs from among a plurality of UEs associated with a target cell by the at least one processor executing one or more instructions. In one embodiment of the present disclosure, the electronic device may set control information for the one or more transfer target UEs set in the RLC layer of the source DU in the RLC layer of the target DU by the at least one processor executing one or more instructions. In one embodiment of the present disclosure, the electronic device may control at least one of a CU or a MAC layer of the target DU to redundantly transmit packets for the one or more transfer target UEs to the RLC layer of the source DU and the RLC layer of the target DU by the at least one processor executing one or more instructions. In one embodiment of the present disclosure, the electronic device may remove information for the one or more transfer target UEs from the RLC layer of the source DU by the at least one processor executing one or more instructions.

[0014] FIG. 1 is a diagram showing an example of a wireless communication system structure according to one embodiment of the present disclosure.

[0015] FIG. 2 may represent an example of a structure in which each layer processes a data packet in a RAN system in one embodiment of the present disclosure.

[0016] FIG. 3 is a flowchart illustrating an example of a method for transferring a target cell from a source DU to a target DU in one embodiment of the present disclosure.

[0017] FIG. 4 is a diagram illustrating an example of a scenario in which a data packet is lost in one embodiment of the present disclosure.

[0018] FIG. 5 is a diagram illustrating an example of a scenario in which data packets are lost during DU scaling in one embodiment of the present disclosure.

[0019] FIG. 6 is a flowchart illustrating an example of a method by which an electronic device transfers a target cell from an RLC layer of a source DU to an RLC layer of a target DU in one embodiment of the present disclosure.

[0020] FIG. 7 is a diagram illustrating an example of data processing in the downlink direction during an RLC layer transfer procedure in one embodiment of the present disclosure.

[0021] FIG. 8 is a diagram illustrating an example of data processing in the uplink direction during an RLC layer transfer procedure in one embodiment of the present disclosure.

[0022] FIG. 9 is a diagram illustrating an example of an operating method of an electronic device according to one embodiment of the present disclosure.

[0023] FIG. 10 is a drawing showing an example of an electronic device according to one embodiment of the present disclosure.

[0024] This disclosure may be subject to various modifications and various embodiments. Specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the disclosure to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the disclosure.

[0025] When describing embodiments, detailed descriptions of related known technologies are omitted if they are deemed to unnecessarily obscure the main point. Furthermore, numbers (e.g., "first," "second," etc.) used in the description of embodiments are merely identifiers used to distinguish one component from another. Furthermore, unless the context clearly indicates otherwise, the singular forms "a," "an," and "the" are understood to include plural references.

[0026] It should be understood that the blocks and combinations of flowcharts in each flowchart can be executed by one or more computer programs containing computer-executable instructions. The one or more computer programs may be stored entirely in a single memory, or may be stored in separate portions across multiple different memories.

[0027] All functions or operations described in this document may be performed by a single processor or a combination of processors. A single processor or a combination of processors is a circuitry that performs processing, and may include circuitry such as an Application Processor (AP), a Communication Processor (CP), a Graphical Processing Unit (GPU), a Neural Processing Unit (NPU), a Microprocessor Unit (MPU), a System on Chip (SoC), or an Integrated Chip (IC).

[0028] Below, with reference to the attached drawings, embodiments of the present disclosure are described in detail to facilitate implementation by those skilled in the art. However, the present disclosure may be implemented in various different forms and is not limited to the embodiments described herein. Before proceeding with a detailed description of the invention, the terms used herein are defined or understood as follows.

[0029] When a component is referred to herein as being "connected" or "connected" to another component, it should be understood that the component may be directly connected to or connected to the other component, but may also be connected or connected via another component in between, unless otherwise specifically stated. Furthermore, "connection" may include a wireless connection or a wired connection.

[0030] In addition, in this specification, components expressed as 'unit', 'module', etc. may be two or more components combined into one component, or one component may be divided into two or more components with more detailed functions. In addition, each component described below may additionally perform some or all of the functions performed by other components in addition to its own main function, and of course, some of the main functions performed by each component may be performed exclusively by other components.

[0031] In the present disclosure, the expression 'at least one of a, b, or c' can refer to 'a', 'b', 'c', 'a and b', 'a and c', 'b and c', 'all of a, b, and c', or variations thereof. In the present disclosure, the expression 'a or b' can refer to 'a', 'b', 'a and b', or variations thereof. In the present disclosure, the expression 'a (or, b, c)' or the expression 'a, b, or c' can refer to 'a', 'b', 'c', 'a and b', 'a and c', 'b and c', 'all of a, b, and c', or variations thereof.

[0032] In one embodiment of the present disclosure, 'transferring C from A to B' may include changing, switching, or updating a device or module that manages or processes information or data associated with C from A to B. For example, 'transferring C from A to B' may include storing, including, or setting information or data associated with C, which is stored, included, or set in device (or module) A, in device (or module) B, in order to change, switch, or update a device or module that manages or processes information or data associated with C from A to B. For example, 'transferring C from A to B' may include storing, including, or setting information or data associated with C, which is stored, included, or set in device A (or module A), in device B (or module B), and removing, deleting, or releasing information or data associated with C in device A (or module A). For example, module A and module B may be modules that are separated or distinct from each other in hardware or software.

[0033] In one embodiment of the present disclosure, 'A performing operation B' may include 'A directly performing operation B' or 'A controlling C to perform operation B'. In one embodiment of the present disclosure, 'A controlling operation B' may include 'A directly performing operation B' or 'A controlling C to perform operation B'.

[0034] In one embodiment of the present disclosure, a 'UE associated with a cell' may include a UE connected to 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 through a cell, a UE transmitting and receiving data through a cell, a UE accessing a network through a cell, a UE included in the range of a cell (e.g., effective range, communication range), a UE requesting a radio resource of a cell, or a UE allocated a radio resource of a cell, etc.

[0035] In one embodiment of the present disclosure, a 'cell context' may include information about basic settings, operation methods, configurations or parameters of each cell in a wireless communication system. For example, a 'cell context' may include information about a frequency band, a channel band, frequency allocation information, transmission output power settings, a cell identifier, settings in the time and frequency domain, interference management with other cells and base stations, scheduling information (e.g., DL (Downlink) / UL (Uplink) Max Resource Block, PDSCH (Physical Downlink Shared Channel), PUSCH (Physical Uplink Shared Channel), SSB (Synchronization Signal Block), etc.), or timing information (e.g., number of slots per flame, etc.). For example, a cell context for a target cell may be used to manage and process communications of UEs associated with the target cell. For example, a cell context for a target cell may include information that is common or shared between UEs associated with the target cell.

[0036] In one embodiment of the present disclosure, a 'UE context' may include information for wireless communication of a UE in a wireless communication system. For example, a UE context for a target UE may include data (e.g., user data, data packets, etc.) transmitted and received between an application server, a core network, or a Radio Access Network (RAN) and the target UE, or control information used to process or manage the aforementioned data. For example, a 'UE context' may include location information of the terminal, a terminal identifier, a status of the terminal, service requirements, information about the network and cell currently in use, performance information of the terminal, function information, security information, or authentication information. For example, the 'UE context' may include a unique number for each situation of UEs connected to the base station (e.g., RNTI (Radio Network Temporary Identifier)), information about DL Data Volume per UE (e.g., BO (Buffer Occupancy)), information about UL Data Volume per UE (e.g., BSR (buffer status report)), a PDCCH (Physical Downlink Control Channel) monitoring period for the UE to transmit and receive new DL / UL traffic (e.g., DRX (Discontinuous Reception)), and retransmission information per UE (e.g., HARQ (Hybrid Automatic Repeat Request) information). For example, the 'UE context' may include different parameter values ​​or data for multiple UEs associated with the same cell. For example, the 'UE context' may include common parameter values ​​or data for multiple UEs associated with the same cell.

[0037] In one embodiment of the present disclosure, a "connection relationship" may include the meaning of a "connection relationship," a "inclusion relationship," an "attachment relationship," or a "matching relationship." For example, "connected" may include the meaning of "connected," "inclusion," "attachment," or "matched." In one embodiment of the present disclosure, "connection" may include the meaning that data communication is possible, either wired or wireless. For example, "A and B are connected" may include the meaning that A and B are capable of data communication, i.e., can transmit and receive data with each other.

[0038] 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. For example, a 'path to a target cell' or an 'interface to a target cell' may include a path through which data associated with the target cell is transmitted and received, or an interface used to transmit and receive data associated with the target cell. For example, a 'path to a target UE' or an 'interface to a target UE' may include a path through which data associated with the target UE is transmitted and received, or an interface used to transmit and receive data associated with the target UE. In one embodiment of the present disclosure, 'establishing (or activating) an interface between A and B' may include the meaning of establishing a configuration through which A and B can transmit and receive data with each other and process the received data.

[0039] In one embodiment of the present disclosure, 'Scale-out for a DU' and 'Scaling-out for a DU' may include adding a new DU to a DU pool containing DUs. In one embodiment of the present disclosure, 'Scale-out for a DU' and 'Scaling-out for a DU' may include transferring cells contained in a DU to another DU (e.g., a newly added DU).

[0040] In one embodiment of the present disclosure, 'Scale-in for a DU' and 'Scaling-in for a DU' may include removing a DU from a DU pool. In one embodiment of the present disclosure, 'Scale-in for a DU' and 'Scaling-in for a DU' may include transferring cells included in a DU to another DU (e.g., an existing DU).

[0041] FIG. 1 is a diagram showing an example of a wireless communication system structure according to one embodiment of the present disclosure.

[0042] In one embodiment of the present disclosure, a wireless communication system may include a core network (110) and a radio access network (RAN) (120). The core network (110) may include user authentication information for each telecommunications company, and may be a platform network that is wired and connected to servers and systems of various service providers via optical cables.

[0043] In one embodiment of the present disclosure, the RAN (120) may include at least one RU (Radio Unit) (128_1, 128_2, 128_3, 128_4, 128_5, 128_6), at least one DU (Distributed Unit) (124_1, 124_2, 124_3, 124_4), and a CU (centralized unit) (122). In one embodiment of the present disclosure, the RAN (120) may include, but is not limited to, a vRAN (virtualized Radio Access Network) system. For example, the RAN (120) may include a 5GS (5G System), 4GS, or other wireless communication system, and may also refer to a wireless communication system to be developed in the future.

[0044] In one embodiment of the present disclosure, the CU (122) may be an entity that performs functions of some layers among the protocol layers of a network. For example, the CU (122) 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 (122) can process are not limited to the functions of the RRC layer and the PDCP layer described above. For example, the CU (122) may perform functions such as QoS (Quality of Service) setting, packet reordering, and security setting and processing. For example, the CU (122) may mean a vCU (virtualized-CU) of a vRAN system, but is not limited thereto.

[0045] One CU (122) can be connected to N DUs, where N can be any integer greater than 1. The CU (122) and the DUs (124_1, 124_2, 124_3, 124_4) can be connected by an interface. For example, the interface between the CU (122) and the DUs (124_1, 124_2, 124_3, 124_4) can be an F1 interface (or a mid-hole interface). For example, the F1 interface can include F1-C, which is an F1 interface of a control plane, and F1-U, which is an F1 interface of a user plane.

[0046] RAN (120) may include DU (124_1), DU (124_2), and DU (124_3). DU (124_1), DU (124_2), and DU (124_3) may perform the same function, but DU (124_3) is described as an example below.

[0047] In one embodiment of the present disclosure, DU (124_3) may be an entity that performs functions of some layers among the protocol layers of the network except for some layers performed by CU (122). For example, DU (124_3) may be an entity that performs network functions (e.g., baseband functions) of RLC (Radio Link Control) layer, MAC (Medium Access Control) layer, and PHY (Physical) layer, but the functions that DU (124_3) can process are not limited to the functions of the RLC layer, MAC layer, and PHY layer described above. For example, DU (124_3) may perform a buffer function, a radio resource scheduling function, a data reprocessing function, etc. For example, DU (124_3) may be a vDU (virtualized-DU) of a vRAN system, but is not limited thereto. For example, DU (124_3) may correspond to a component module, an arbitrary processing operation unit, a distribution unit performing arbitrary processing, software, etc. For example, DU (124_3) may correspond to one server.

[0048] One DU can be connected to N RUs, where N can be any integer greater than 1. Referring to FIG. 1, DU (124_1) can be connected to RU (128_1), ..., and RU (128_2), DU (124_2) can be connected to RU (128_3), ..., and RU (128_4), and DU (124_3) can be connected to RU (128_5), ..., and RU (128_6). In one embodiment of the present disclosure, DU (124_3) and RU (128_5, 128_6) can be connected by an interface. For example, the interface between DU (124_3) and RU (128_5, 128_6) can be a front haul interface.

[0049] RU(128_1), RU(128_2), RU(128_3), RU(128_4), RU(128_5) and RU(128_6) can perform the same function, but RU(128_6) is described as an example below.

[0050] In one embodiment of the present disclosure, RU (128_6) may be an entity that performs some functions of the PHY layer other than those handled by DU (124_3). For example, DU (124_3) may perform the function of the high-PHY layer, and RU (128_6) may perform the function of the low-PHY layer. For example, RU (128_6) may perform a data transmission and reception function via an RF antenna.

[0051] In existing RAN systems, a DU can be connected 1:1 to a cell site containing one or more RUs, and the DU's processing capacity can be determined based on the maximum traffic that can enter the cell site. Based on traffic trends over time, the peak traffic hours are limited (e.g., 5:00 PM to 9:00 PM), and outside of these hours, unused DU resources, i.e., remaining available resources, may exist.

[0052] According to one embodiment of the present disclosure, a vRAN system may employ a virtualized DU (vDU) pooling technology that breaks the 1:1 relationship between existing DUs and cell sites (a collection of RUs) and virtualizes DUs by pooling them. This can reduce the number of servers required to build a RAN system and reduce capital expenditures (CAPEX). Furthermore, compared to existing RAN systems, power consumption can be reduced and operating expenditures (OPEX) can be reduced.

[0053] A vRAN system according to one embodiment of the present disclosure may employ vCU pooling technology, which pools and virtualizes CUs. This can reduce the number of servers required to build a RAN system and reduce capital expenditures (CAPEX). Furthermore, compared to existing RAN systems, power consumption can be reduced and operating expenditures (OPEX) can be reduced.

[0054] In one embodiment of the present disclosure, a vDU scaling method may be used in the RAN (120) to efficiently utilize server resources by dynamically scaling out or scaling in DUs according to current traffic conditions. In the case of scaling out, a DU (124_4) may be newly created in the RAN (120), but is not limited thereto. For example, the DU (124_4) may already exist in the RAN (120). In the case of scaling in, the DU (124_4) may already exist in the RAN (120).

[0055] Hereinafter, DU (124_3) may be denoted as the first DU (124_3), and DU (124_4) may be denoted as the second DU (124_4). In the case of scale-out in FIG. 1, the first DU (124_3) may correspond to the source DU, and the second DU (124_4) may correspond to the target DU. In the case of scale-in in FIG. 1, the first DU (124_3) may correspond to the target DU, and the second DU (124_4) may correspond to the source DU. The first DU (124_3) and the second DU (124_4) may be connected via an inter DU interface (Xd interface) (126).

[0056] In one embodiment of the present disclosure, scale-out may include adding a new DU (e.g., a second DU (124_4)) to the DU pool for the CU (122). For example, when the amount of traffic that a first DU (124_3) included in the DU pool must process increases, a second DU (124_4) may be added to the DU pool. For example, adding the second DU (124_4) to the DU pool may include adding a module corresponding to the second DU (124_4) to the DU pool. For example, adding the second DU (124_4) to the DU pool may include initiating operation of an additional server capable of processing data. When the capacity or performance of processing data of the first DU (124_3) (e.g., an existing server) reaches its limit, a second DU (124_4) (a non-limiting example, a server with similar specifications) can be added to the communication system using scale-out. In this case, the cell whose data is being processed by the first DU (124_3) can be migrated from the first DU (124_3) to the second DU (124_4), so that the cell's data can be processed by the second DU (124_4).

[0057] In an embodiment of the present disclosure, scale-in may include removing a second DU (124_4) included in a DU pool. For example, when the amount of traffic that the DUs included in the DU pool must process decreases, the second DU (124_4) may be removed from the DU pool. For example, removing the second DU (124_4) from the DU pool may include removing a module corresponding to the second DU (124_4). For example, removing the second DU (124_4) from the DU pool may include stopping the operation of a server that was processing data. By using scale-in, the number of servers that are no longer needed to operate can be reduced, and resources can be saved. For scale-in, a cell whose data is processed by the second DU (124_4) may be migrated from the second DU (124_4) to the first DU (124_3), so that the cell's data is processed by the first DU (124_3).

[0058] In one embodiment of the present disclosure, in addition to the case of scaling by adding or removing the second DU (124_4) from the DU pool, a cell whose data is processed by the second DU (124_4) may be migrated from the second DU (124_4) to the first DU (124_3) so that the cell's data is processed by the first DU (124_3), or a cell whose data is processed by the first DU (124_3) may be migrated from the first DU (124_3) to the second DU (124_4) so ​​that the cell's data is processed by the second DU (124_4). For example, a cell may be migrated from the first DU (124_3) with a large traffic volume to the second DU (124_4) with a relatively small traffic volume so that the cell's data is processed by the second DU (124_4).

[0059] In one embodiment of the present disclosure, a method or device may be provided for transferring a plurality of UEs associated with a target cell from an RLC layer of a source DU to an RLC layer of a target DU to transfer the target cell from a source DU to a target DU. In one embodiment of the present disclosure, a method or device may be provided for transferring a plurality of UEs from an RLC layer of a source DU to an RLC layer of a target DU on a UE-by-UE basis. According to one embodiment of the present disclosure, it is possible to eliminate communication delay while preventing service failure (e.g., Radio Link Failure (RLF)) that may occur during transfer of UEs from an RLC layer of a source DU to an RLC layer of a target DU.

[0060] FIG. 2 may represent an example of a structure in which each layer processes a data packet in a RAN system in one embodiment of the present disclosure.

[0061] In explaining Fig. 2, any explanation that overlaps with the explanation given above in Fig. 1 may be omitted.

[0062] A RAN system may include multiple protocol layers, and at least one protocol layer may constitute a CU or a DU. For example, a CU may include a Service Data Application Protocol (SDAP) layer (210) and a Packet Data Convergence Protocol (PDCP) layer (220), and a DU may include, but is not limited to, an RLC layer (230) and a MAC layer (240). Each layer may receive a packet of a Service Data Unit (SDU) from an upper layer, and transmit a packet of a Protocol Data Unit (PDU) to a lower layer. For example, each layer may add a header (H) to a packet of a received SDU and transmit it to a lower layer.

[0063] The SDAP layer (210) can map QoS bearers and radio bearers (RBs) according to QoS requirements. For example, the SDAP layer (210) can map IP packets to radio bearers. Referring to FIG. 2, the SDAP layer (210) can map IP packets n and IP packet n+1 to RB x, and map IP packet m to RB y.

[0064] The PDCP layer (220) can perform IP (Internet Protocol) header compression, encryption, or integrity protection, and can handle duplication deletion during retransmission, sequential delivery, or handover. The RLC layer (230) can manage data of applications used by users in the form of packets and manage them by assigning a sequence number to each packet. The RLC layer (230) can handle segmentation or retransmission. The MAC layer (240) can handle multiplexing of logical channels, HARQ retransmission, or scheduling-related functions.

[0065] Referring to FIG. 2, an RLC SDU packet (i.e., a PDCP PDU packet) can be transmitted from a PDCP layer (220) to an RLC layer (230), and the RLC layer (230) can add a header to the received RLC SDU packet. Additionally or alternatively, the RLC layer (230) can segment an RLC SDU packet received from the PDCP layer (220) into multiple RLC SDU segments and add a header to each SDU segment.

[0066] The PDCP layer (220) and the RLC layer (230) can assign sequence numbers to packets and manage them separately. For example, the PDCP layer (220) can assign sequence numbers to packets of the PDCP layer (e.g., PDCP SDU packets or PDCP PDU packets) for packet deduplication or packet reordering. The RLC layer (230) can assign sequence numbers to packets of the RLC layer (e.g., RLC SDU packets, RLC PDU packets, or RLC SDU segment packets) for retransmission in communication between a base station and a user terminal.

[0067] Packets may be split or merged between the RLC layer (230) and the PDCP layer (220), and since the RLC layer (230) and the PDCP layer (220) may each assign sequence numbers to packets, the sequence numbers of the RLC layer (230) and the PDCP layer (220) may be different. In the present disclosure, for the convenience of explanation, data may be identified or distinguished based on the PDCP sequence number or PDCP packet, but is not limited thereto. For example, it may be explained assuming that the RLC layer (230) and the PDCP layer (220) assign the same sequence number to packets for the same data without packet splitting or packet merging between the RLC layer (230) and the PDCP layer (220).

[0068] Figure 2 illustrates the SDAP layer (210), PDCP layer (220), RLC layer (230), and MAC layer (240) as protocol layers included in the RAN, but is not limited thereto. For example, the RAN may further include other layers. For example, the RAN may further include a PHY layer that performs functions such as coding / decoding, modulation / demodulation, or multi-antenna mapping, and the PHY layer may be included in a DU or RU.

[0069] FIG. 3 is a flowchart illustrating an example of a method for transferring a target cell from a source DU to a target DU in one embodiment of the present disclosure.

[0070] In explaining Fig. 3, any explanation that overlaps with the explanation given above in Fig. 1 or Fig. 2 may be omitted.

[0071] Referring to FIG. 3, a method (300) according to one embodiment of the present disclosure may include steps 310 to 332. In one embodiment of the present disclosure, steps 310 to 332 may be executed by at least one processor included in an electronic device. In one embodiment of the present disclosure, steps 310 to 332 may be performed by a scaling agent module included in the electronic device. The method (300) is not limited to that illustrated in FIG. 3, and in one or more embodiments, steps not illustrated in FIG. 3 may be further included, or some steps may be omitted.

[0072] In one embodiment of the present disclosure, a method (300) for transferring a target cell from a source DU to a target DU may include a MAC / PHY layer transfer procedure of the target cell and a RLC layer transfer procedure of the target cell. For example, referring to FIG. 3, the MAC / PHY layer transfer procedure of the target cell may include steps 310 to 320, and the RLC layer transfer procedure of the target cell may include steps 322 to 332. According to one embodiment of the present disclosure, the MAC / PHY layer transfer method and the RLC layer transfer method may be different. For example, in order to reduce the complexity that may occur when operating two fronthaul interfaces and a MAC Scheduler, the target cell may be transferred on a cell-by-cell basis in the MAC / PHY layer transfer procedure of the target cell, whereas in the RLC layer transfer procedure, the target cell may be transferred on a UE-by-UE basis for stable transfer operation.

[0073] In step 310, the electronic device may transfer a cell context for a target cell (e.g., a previous target cell) of the RLC layer, MAC layer, or PHY layer of the source DU to the RLC layer, MAC layer, or PHY layer of the target DU. For example, the electronic device may copy or set a cell context for a target cell included, stored, or set in the RLC layer of the source DU to the RLC layer of the target DU. For example, the electronic device may copy or set a cell context for a target cell included, stored, or set in the MAC layer of the source DU to the MAC layer of the target DU. For example, the electronic device may copy or set a cell context for a target cell included, stored, or set in the PHY layer of the source DU to the PHY layer of the target DU. For example, at least some of the RLC layer, the MAC layer, or the PHY layer may include or store different types of cell contexts.

[0074] In step 312, the electronic device may switch (or change) the fronthaul interface for the target cell from the source DU to the target DU. For example, the electronic device may release (or disable) the fronthaul interface between the source DU and the RU, and establish (or enable) the fronthaul interface between the target DU and the RU, for the target cell. For example, switching the fronthaul interface may include switching of a logical path as well as a physical switching. For example, the electronic device may update (or change) the destination of an uplink packet for the target cell of the RU from the source DU to the target DU. For example, the electronic device may set the destination of a downlink packet for the target cell of the target DU (e.g., the PHY layer of the target DU) to the RU.

[0075] In step 314, the electronic device may transfer UE contexts for a plurality of UEs (e.g., all UEs) associated with the target cell from the MAC layer or PHY layer of the source DU to the MAC layer or PHY layer of the target DU. For example, the electronic device may duplicate or set UE contexts (e.g., MAC contexts) for a plurality of UEs that are stored, included, or set in the MAC layer of the source DU to the MAC layer of the target DU. For example, the electronic device may duplicate or set UE contexts (e.g., PHY contexts) for a plurality of UEs that are stored, included, or set in the PHY layer of the source DU to the PHY layer of the target DU. For example, the electronic device may change the MAC layer that manages or processes data for a plurality of UEs associated with the target cell from the MAC layer of the source DU to the MAC layer of the target DU. For example, the electronic device may change the PHY layer that manages or processes data for a plurality of UEs associated with the target cell from the PHY layer of the source DU to the PHY layer of the target DU.

[0076] In step 316, the electronic device may establish (or activate) a connection between the RLC layer of the source DU and the MAC layer of the target DU for the target cell. For example, the electronic device may switch the RLC-MAC path for the target cell from the RLC layer of the source DU - the MAC layer of the source DU to the RLC layer of the source DU - the MAC layer of the target DU. For example, the RLC-MAC path for the target cell may include a path along which data packets for the target cell are transmitted and received. For example, the electronic device may update (or change) the destination of a downlink packet for the target cell of the RLC layer of the source DU from the MAC layer of the source DU to the MAC layer of the target DU. For example, the electronic device may set (or update) the destination of an uplink packet for the target cell of the MAC layer of the target DU to the RLC layer of the source DU.

[0077] Referring to FIG. 3, the electronic device can perform steps 314 and 316 and step 312 in parallel. For example, the electronic device can perform steps 314 and 316 and step 312 simultaneously. However, the operational sequence of steps 312 to 316 is not limited to that illustrated in FIG. 3. For example, the electronic device can perform at least some of steps 312 to 316 simultaneously or sequentially. For example, the electronic device can perform steps 312 to 316 independently or dependently.

[0078] In step 318, the electronic device can identify whether the communication service of the target cell is successfully provided. For example, the electronic device can determine whether the communication service of the target cell is successfully provided, or receive information regarding whether the communication service of the target cell is successfully provided. For example, the electronic device can identify whether the UE associated with the target cell can successfully connect to the communication network, whether the UE associated with the target cell is in a communication state, and whether the UE associated with the target cell is experiencing a communication failure.

[0079] If the electronic device identifies that the communication service of the target cell is not successfully provided, the electronic device may re-perform at least one of steps 310 to 316 described above.

[0080] If it is identified that the communication service of the target cell is successfully provided, in step 320, the electronic device may remove the cell context for the target cell or the UE context for the UE associated with the target cell from the MAC layer or PHY layer of the source DU.

[0081] In step 322, the electronic device may select a UE to be transferred to the RLC layer of the target DU from among a plurality of UEs associated with the target cell. For example, the electronic device may select one or more target UEs from among the plurality of UEs to transfer a UE context from the RLC layer of the source DU to the RLC layer of the target DU. For example, if the plurality of UEs associated with the target cell include a first UE, a second UE, and a third UE, and the RLC layer of the source DU includes a UE context for the first UE, a UE context for the second UE, and a UE context for the third UE, the electronic device may select the first UE and the second UE as target UEs from among the plurality of UEs associated with the target cell.

[0082] In step 324, the electronic device can identify whether there is a UE to be transferred to the RLC layer of the target DU. For example, if one or more target UEs are selected as UEs to be transferred to the RLC layer of the target DU in step 322, the electronic device can identify that there is a UE to be transferred. For example, if the electronic device performs an operation to select a UE to be transferred to the RLC layer of the target DU from among a plurality of UEs in step 322 but fails to select a UE to be transferred, the electronic device can identify that there is no UE to be transferred. For example, if a plurality of UEs have already been transferred to the RLC layer of the target DU, the electronic device can identify that there is no UE to be transferred.

[0083] If there is a UE to be transferred among multiple UEs associated with the target cell, in step 326, the electronic device may transfer the UE context for the selected UE (hereinafter, 'target UE') from the RLC layer of the source DU to the RLC layer of the target DU. For example, the electronic device may duplicate or set the UE context (e.g., RLC context) for the target UE, which is stored, included, or set in the RLC layer of the source DU, to the RLC layer of the target DU. For example, the electronic device may change (or update) the RLC layer that manages or processes data for the target UE from the RLC layer of the source DU to the RLC layer of the target DU.

[0084] In step 328, the electronic device may change (or switch) the F1-U path (e.g., the midhaul interface) for the target UE from the source DU to the target DU. For example, the electronic device may switch the F1-U path from the CU-source DU (e.g., the RLC layer of the CU-source DU) to the CU-target DU (e.g., the RLC layer of the CU-target DU) for the target UE. For example, the electronic device may update the destination of a downlink packet for the target UE of the CU from the RLC layer of the source DU to the RLC layer of the target DU. For example, the electronic device may set the destination of an uplink packet for the target UE of the RLC layer of the target DU to the CU.

[0085] In step 330, the electronic device may change (or switch) the RLC-MAC path for the target UE from a source DU-target DU path (e.g., an RLC layer of the source DU-MAC layer path of the target DU) to a target DU-target DU path (e.g., an RLC layer of the target DU-MAC layer path of the target DU). For example, the electronic device may establish (or activate) a connection (or interface) between the RLC layer and the MAC layer of the target DU for the target UE, and release (or deactivate) a connection (or interface) between the RLC layer of the source DU and the MAC layer of the target DU. For example, the electronic device may set a destination of a downlink packet for the target UE of the RLC layer of the target DU to the MAC layer of the target DU. For example, the electronic device may update a destination of an uplink packet for the target UE of the MAC layer of the target DU from the RLC layer of the source DU to the RLC layer of the target DU.

[0086] Although FIG. 3 illustrates the electronic device sequentially performing steps 326 to 330 described above, this is not limiting. For example, the electronic device may perform at least some of the steps 326 to 330 described above simultaneously, in parallel, or independently.

[0087] Referring to FIG. 3, the electronic device may repeat at least one of steps 322 to 330 until there is no UE to be transferred to the RLC layer of the target DU. For example, the electronic device may repeat steps 322 to 330 until there is no UE among a plurality of UEs associated with the target cell whose UE context has not been transferred from the RLC layer of the source DU to the RLC layer of the target DU.

[0088] If there is no UE to be transferred, in step 332, the electronic device may remove (or delete, release) information related to the target cell from the RLC layer of the source DU. For example, the electronic device may delete a cell context for the target cell included, stored, or set in the RLC layer of the source DU, or a UE context for multiple UEs associated with the target cell.

[0089] Although FIG. 3 illustrates that the electronic device removes the UE context included in the RLC layer of the source DU after transferring all UEs associated with the target cell to the RLC layer of the target DU, the present invention is not limited thereto. For example, the electronic device may remove (or delete, release) the UE context transferred to the RLC layer of the target DU after at least one of steps 326, 328, or 330. For example, the electronic device may periodically or aperiodically remove the UE context for the transferred UE from the RLC layer of the source DU.

[0090] In one embodiment of the present disclosure, a method for transferring a target cell from a source DU to a target DU may further include steps not illustrated in FIG. 3 . For example, prior to step 310, the electronic device may identify (or determine) that DU scaling in or out is required. For example, prior to step 310, the electronic device may generate a target DU and connect to an F1 Application Protocol (F1AP). For example, upon completion of the cell transfer, the electronic device may transmit information indicating that the cell transfer is complete to a network element management system (EMS) (or a configuration module managed by a mobile carrier operator).

[0091] Additionally, although FIG. 3 illustrates that the electronic device performs an RLC transfer procedure after a MAC / PHY transfer procedure, it is not limited thereto.

[0092] FIG. 4 is a diagram illustrating an example of a scenario in which a data packet is lost in one embodiment of the present disclosure.

[0093] In explaining Fig. 4, any explanation that overlaps with the explanation given above in any one of Figs. 1 to 3 may be omitted.

[0094] A UE (440) connected to a wireless network can transmit and receive user data (e.g., service data used by the user, data of an application used by the user) in the form of data packets through the CU (410), DU (420), and RU (430). For example, in a communication procedure in the downlink direction, user data can be transmitted in the form of data packets from the CU (410) to the DU (420), from the DU (420) to the RU (430), and from the RU (430) to the UE (440). For example, in a communication procedure in the uplink direction, user data can be transmitted in the form of data packets from the UE (440) to the RU (430), from the RU (430) to the DU (420), and from the DU (420) to the CU (410).

[0095] FIG. 4 may illustrate an example of a scenario in which a data packet (e.g., a packet of an RLC layer) is lost during wireless communication between an RU (430) and a UE (440) in a downlink communication procedure. The RLC layer (422) of the DU (420) may segment or fuse packets received from the CU (410), or may assign a new sequence number independent of the sequence number assigned by the CU (410). However, for clarity, FIG. 4 may illustrate the packet format and sequence number used to generate and transmit user data in the entire downlink communication procedure.

[0096] Referring to FIG. 4, the CU (410) can sequentially transmit data packets for the UE (440) to the DU (420) via the F1-U path (e.g., midhaul interface). For example, the CU (410) can sequentially transmit packets 1 to 5 to the RLC layer (422) of the DU (420). Although FIG. 4 illustrates an example in which the CU (410) transmits packets to the DU (420) in sequence number order, the present invention is not limited thereto.

[0097] The RLC layer (422) of the DU (420) assigns a sequence number to the received user data for the UE (440) and transmits it to the MAC layer, and the MAC layer can transmit the user data for the UE (440) to the PHY layer. The DU (420) can transmit the user data for the UE (440) to the RU (430). For example, the DU (420) can transmit the user data for the UE (440) to the RU (430) via the fronthaul interface. The RU (430) can transmit the user data to the UE (440).

[0098] Since CU (410), DU (420), and RU (430) are connected to each other by wire and can transmit and receive data by wire, data loss may not occur in data transmission and reception between CU (410), DU (420), and RU (430). On the other hand, RU (430) and UE (440) are connected to each other wirelessly and can transmit and receive data wirelessly, and data loss may occur in data transmission and reception between RU (430) and UE (440). Referring to FIG. 4, when user data for UE (440) is transmitted wirelessly from RU (430) to UE (440), packet 3 (e.g., user data corresponding to packet 3) may be lost. For example, RU (430) may transmit packet 3 to UE (440), but packet 3 may be lost without reaching UE (440) due to a communication channel issue, etc.

[0099] The UE (440) may transmit a response indicating whether user data has been received to the RLC layer (422) of the DU (420) via the RU (430). For example, when the UE (440) receives packets 1 and 2, the UE (440) may transmit a response (e.g., packet reception acknowledgement, ACK) indicating that packets 1 and 2 have been received. For example, when the UE (440) does not receive packet 3, the UE (440) may transmit a response (e.g., retransmission request, NACK) indicating that packet 3 has not been received. For example, the UE (440) may request retransmission of packet 3 by transmitting a NACK for packet 3. For example, the UE (440) may repeatedly request retransmission of packet 3 periodically or aperiodically until packet 3 is received.

[0100] The RLC layer (422) of the DU (420) can remove or retransmit data packets stored or included in the packet buffer (424) according to a response (e.g., ACK or NACK) transmitted from the UE (440). Referring to FIG. 4, the RLC layer (422) can receive ACKs for packets 1 and 2 from the UE (440) and remove packets 1 and 2 from the packet buffer (424). In addition, the RLC layer (422) can receive NACKs for packet 3 from the UE (440) and retransmit packet 3 to the UE (440). Meanwhile, if packet 3 does not reach the UE (440) within a predetermined reference time (e.g., a time from 1 ms to 2 s) despite a retransmission request from the UE (440), a disconnection in the communication network connection of the UE (440) may occur.

[0101] Although Fig. 4 illustrates packet loss in downlink communication, packet loss may also occur in wireless communication between RU (430) and UE (440) during uplink communication, similar to downlink communication.

[0102] FIG. 5 is a diagram illustrating an example of a scenario in which data packets are lost during DU scaling in one embodiment of the present disclosure.

[0103] In explaining Fig. 5, any explanation that overlaps with the explanation given above in any one of Figs. 1 to 4 may be omitted.

[0104] FIG. 5 may illustrate an example of a scenario in which data packets are lost in data transmission and reception between RU (430) and UE (440) during an RLC layer transfer procedure in one embodiment of the present disclosure. For example, FIG. 5 may illustrate an example in which data packets are lost between RU (430) and UE (440) during an RLC layer transfer procedure after a MAC / PHY layer transfer procedure. Although FIG. 5 illustrates packet loss in downlink communication during an RLC layer transfer procedure, packet loss between RU (430) and UE (440) may also occur in uplink communication during an RLC layer transfer procedure, similar to downlink communication.

[0105] In one embodiment of the present disclosure, the electronic device may perform an RLC transfer procedure to change or switch the RLC layer processing data of the target UE (440) from the RLC layer (512) of the source DU (510) to the RLC layer (522) of the target DU (520). The RLC layer (512) of the source DU (510) may store, include, or set a UE context for the target UE (440), and the UE context for the target UE (440) may include user data (e.g., data packets) for the target UE (440) or control information (e.g., entity context) used to process user data for the target UE (440). For example, the electronic device may copy or set control information for the target UE (440) stored, included, or set in the RLC layer (512) of the source DU (510) to the RLC layer (522) of the target DU (520) in order to change or switch the RLC layer processing data of the target UE (440) from the RLC layer (512) of the source DU (510) to the RLC layer (522) of the target DU (520). In this case, user data (e.g., data packets) for the target UE (440) stored or included in the RLC layer (512) of the source DU (510) may not be copied or transferred to the RLC layer (522) of the target DU (520).

[0106] Downlink data (e.g., downlink packets) for the target UE (440) already stored or included in the RLC layer (512) of the source DU (510) can be transmitted to the MAC layer (526) of the target DU (520), from the MAC layer (526) of the target DU (520) to the PHY layer (528) of the target DU (520), from the target DU (520) to the RU (430), and from the RU (430) to the target UE (440). After the RLC layer, downlink data for the target UE (440) can be transmitted from the CU (410) to the RLC layer (522) of the target DU (520), from the RLC layer (522) of the target DU (520) to the MAC layer (526) of the target DU (520), from the MAC layer (526) of the target DU (520) to the PHY layer (528) of the target DU (520), from the target DU (520) to the RU (430), and from the RU (430) to the target UE (440).

[0107] Referring to FIG. 5, the CU (410) can sequentially transmit packets 1 to 6, which are downlink data for the target UE (440), to the target UE (440). Before the RLC layer for the target UE (440) is transferred and the midhaul interface and the RLC-MAC path are switched, the CU (410) can transmit packets 1 and 2 to the target UE (440) through the RLC layer (512) of the source DU (510), and the RLC layer (512) of the source DU (510) can remove packets 1 and 2 from the packet buffer (514) upon receiving an ACK indicating that it has received packets 1 and 2 from the target UE (440).

[0108] After the CU (410) transmits packets 3 and 4 to the RLC layer (512) of the source DU (510), the RLC layer for the target UE (440) may be transferred and the midhaul interface may be switched, so that the CU (410) may transmit packets 5 and 6 to the RLC layer (522) of the target DU (520). The RLC layer (512) of the source DU (510) can transmit packets 3 and 4 to the target UE (440) through the MAC layer (526), ​​PHY layer (528), and RU (430) of the target DU (520), and the RLC layer (522) of the target DU (520) can transmit packets 5 and 6 to the target UE (440) through the MAC layer (526), ​​PHY layer (528), and RU (430) of the target DU (520).

[0109] Referring to FIG. 5, packet 3 may be lost in the wireless communication space between RU (430) and target UE (440), so that target UE (440) may receive only packets 4 to 6 and not receive packet 3. Accordingly, target UE (440) may transmit a NACK indicating that packet 3 was not received, and may transmit an ACK indicating that packets 4 to 6 were received, respectively. Since the RLC-MAC path for the target UE (440) is switched, changed, or set from the RLC layer (522) of the target DU (520) to the MAC layer (526) of the target DU (520), the NACK or ACK transmitted by the target UE (440) can be received by the RLC layer (522) of the target DU (520) through the RU (430), the PHY layer (528) and the MAC layer (526) of the target DU (520).

[0110] In this case, since the RLC layer (522) of the target DU (520) does not have packet 3 in the packet buffer (524), even if it receives a NACK for packet 3 from the target UE (440), it cannot retransmit packet 3 to the target UE (440). In addition, since the RLC layer (512) of the source DU (510) does not receive a NACK for packet 3 or an ACK for packet 4 from the target UE (440), it may not retransmit packet 3 or remove packet 4 from the packet buffer (514).

[0111] In a scenario such as that illustrated in FIG. 5, if the target UE (440) does not receive a lost downlink packet (e.g., packet 3 in FIG. 5) within a reference time (e.g., 360 ms), a Radio Link Failure (RLF) may occur, and the target UE (440) may identify a communication service failure for the target cell and perform an operation (e.g., Random Access (RA)) to reconnect to the communication network. Accordingly, additional resource consumption may occur in the target UE (440) and the communication network system, and a degradation of the service quality of the communication network may occur. In addition, the RLC layer (522) of the source DU (520) may not remove packets 3 and 4 from the packet buffer (524), resulting in unnecessary waste of buffer space.

[0112] FIG. 6 is a flowchart illustrating an example of a method by which an electronic device transfers a target cell from an RLC layer of a source DU to an RLC layer of a target DU in one embodiment of the present disclosure.

[0113] In explaining Fig. 6, any explanation that overlaps with the explanation given above in any one of Figs. 1 to 5 may be omitted.

[0114] FIG. 6 may illustrate a method (600) of migrating a target cell from an RLC layer of a source DU to an RLC layer of a target DU in order to migrate the target cell from a source DU to the target DU, in one embodiment of the present disclosure. For example, FIG. 6 may represent a method of migrating, switching, or changing an RLC layer that processes data of a target UE associated with a target cell from a source RLC layer to a target RLC layer. For example, the method (600) of FIG. 6 may be performed after step 320 of the method (300) of FIG. 3 .

[0115] Referring to FIG. 6, a method (600) according to one embodiment of the present disclosure may include steps 610 to 680. In one embodiment of the present disclosure, steps 610 to 680 may be executed by at least one processor included in an electronic device. In one embodiment of the present disclosure, steps 610 to 680 may be performed by a scaling agent module included in the electronic device. The method (600) for migrating a target cell from an RLC layer of a source DU to an RLC layer of a target DU is not limited to that illustrated in FIG. 6, and in one or more embodiments, steps not illustrated in FIG. 6 may be further included, or some steps may be omitted.

[0116] In step 610, the electronic device may select a UE to be transferred to the RLC layer of the target DU. For example, the electronic device may select a UE to be transferred to the RLC layer of the target DU from among multiple UEs associated with the target cell. For example, the electronic device may select a UE to be transferred to the RLC layer of the target DU from among UEs that have not been transferred to the RLC layer of the target DU. For example, the electronic device may select a UE to be transferred to the RLC layer of the target DU from among UEs whose user data is processed by the RLC layer of the source DU.

[0117] At step 620, the electronic device can identify whether there is a UE to transfer.

[0118] If there is a UE to be transferred, in step 630, the electronic device may collect information for RLC layer transfer for the selected UE (hereinafter, referred to as a 'target UE'). In one embodiment of the present disclosure, the electronic device may collect UE context information (e.g., control information for the UE) for the target UE included, stored, or set in the RLC layer of the source DU. In one embodiment of the present disclosure, the electronic device may collect information or data used to include, store, or set the UE context for the target UE in the RLC layer of the source DU.

[0119] In step 640, the electronic device may set, include, or store control information for the target UE in the RLC layer of the target DU. In one embodiment of the present disclosure, the electronic device may copy and store or include, in the RLC layer of the target DU, the UE context for the target UE (e.g., control information for the target UE) included, stored, or set in the RLC layer of the source DU. In one embodiment of the present disclosure, the electronic device may set the UE context for the target UE in the RLC layer of the target DU using information or data used to set, store, or include the UE context for the target UE in the RLC layer of the source DU.

[0120] In step 650, the electronic device may control the CU to transmit downlink packets for the target UE to the RLC layer of the source DU and the RLC layer of the target DU in duplicate. For example, the electronic device may request, instruct, or command a packet transmission module (e.g., a downlink transmission module) included in the CU to transmit duplicate packets. In one embodiment of the present disclosure, the electronic device may control the CU to transmit downlink packets for the target UE to the RLC layer of the source DU and the RLC layer of the target DU in duplicate during the first duplicate transmission time.

[0121] In one embodiment of the present disclosure, an electronic device or CU may initiate RLC sequence number synchronization between an RLC layer of a source DU and an RLC layer of a target DU. For example, the CU may transmit sequence number information to the RLC layer of the target DU every time it transmits a packet to the RLC layer of the source DU.

[0122] In one embodiment of the present disclosure, an electronic device may set a first redundant transmission time in an F1-U transmission module (e.g., a user data packet transmission module) of a CU. For example, the electronic device may indicate or set a start time, duration, end time, or expiration time of the redundant transmission. For example, the electronic device may set or start a timer indicating the first redundant transmission time.

[0123] In one embodiment of the present disclosure, the electronic device or CU may set a packet processing start reference sequence number of the target DU and terminate RLC sequence number synchronization between the RLC of the source DU and the RLC of the target DU. For example, the electronic device or CU may set a sequence number (e.g., a PDCP sequence number or an RLC sequence number) of a packet to start transmission to the target DU.

[0124] In one embodiment of the present disclosure, during the first overlap transmission time, the CU may overlap transmission of downlink data (e.g., user data, data packets, downlink packets) for the target UE to the RLC layer of the source DU and the RLC layer of the target DU. For example, until the first overlap transmission time expires or ends, the CU may overlap transmission of downlink packets for the target UE to the RLC layer of the source DU and the RLC layer of the target DU.

[0125] In step 652, the electronic device may update the downlink destination information for the target UE of the CU from the RLC layer of the source DU to the RLC layer of the target DU during the overlap transmission time (e.g., the first overlap transmission time). For example, the electronic device may switch the midhaul interface (e.g., the F1-U path) for the target UE from the source DU to the target DU during the first overlap transmission time. Even if the downlink destination information is updated or the midhaul interface is switched, the CU may transmit the downlink data (e.g., the downlink packet) for the target UE to the RLC layer of the source DU and the RLC layer of the target DU during the first overlap transmission time. Therefore, the communication network connection of the target UE may not be disconnected even with the update of the destination information or the switching of the midhaul interface.

[0126] In one embodiment of the present disclosure, the electronic device or CU may set a sequence number (e.g., an RLC sequence number or a PDPC sequence number) that the source DU will last process for the target UE in the RLC layer of the source DU when the first redundancy transmission time expires. In one embodiment of the present disclosure, when the first redundancy transmission time expires, the CU may transmit downlink packets for the target UE only to the target DU. For example, since the downlink destination information for the target UE of the CU is updated in step 652, after the first redundancy transmission time expires, the CU may transmit downlink data for the target UE to the RLC layer of the target DU rather than to the RLC layer of the source DU.

[0127] In step 660, the electronic device may control the MAC layer of the target DU to transmit the uplink packet for the target UE to the RLC layer of the source DU and the RLC layer of the target DU in a duplicate manner. For example, the electronic device may request, instruct, or command the packet transmission module (e.g., the uplink transmission module) included in the MAC layer of the target DU to transmit the duplicate manner. In one embodiment of the present disclosure, the electronic device may control the MAC layer of the target DU to transmit the uplink packet for the target UE to the RLC layer of the source DU and the RLC layer of the target DU in a duplicate manner during the second duplicate transmission time.

[0128] In one embodiment of the present disclosure, an electronic device or CU may set reference packets for processing of a source DU and a target DU. For example, the electronic device or CU may set reference packets for the RLC layer of the target DU to begin processing.

[0129] In one embodiment of the present disclosure, the electronic device may set a second redundant transmission time in the uplink transmission module (e.g., a user data packet transmission module) of the MAC layer of the target DU. For example, the electronic device may indicate or set the start time, duration, end time, or expiration time of the redundant transmission. For example, the electronic device may set or start a timer indicating the second redundant transmission time.

[0130] In one embodiment of the present disclosure, during the second overlapping transmission time, the MAC layer of the target DU may overlappingly transmit data (e.g., user data, data packets, uplink packets) in the uplink direction for the target UE to the RLC layer of the source DU and the RLC layer of the target DU. For example, until the second overlapping transmission time expires or ends, the MAC layer of the target DU may overlappingly transmit uplink packets for the target UE to the RLC layer of the source DU and the RLC layer of the target DU.

[0131] In step 662, the electronic device may update the uplink destination information for the target UE in the MAC layer of the target DU from the RLC layer of the source DU to the RLC layer of the target DU during the overlap transmission time (e.g., the second overlap transmission time). For example, the electronic device may switch the RLC-MAC path for the target UE from the RLC layer of the source DU to the MAC layer of the target DU to the RLC layer of the target DU to the MAC layer of the target DU during the second overlap transmission time. Even if the uplink destination information is updated or the RLC-MAC path is switched, the MAC layer of the target DU may transmit the uplink data (e.g., the uplink packet) for the target UE to the RLC layer of the source DU and the RLC layer of the target DU during the second overlap transmission time. Therefore, the communication network connection of the target UE may not be disconnected even with the update of the uplink destination information or the switching of the RLC-MAC path.

[0132] In one embodiment of the present disclosure, the electronic device or CU may set a sequence number (e.g., an RLC sequence number or a PDPC sequence number) that the source DU will last process for the target UE in the RLC layer of the source DU when the second overlap transmission time expires. In one embodiment of the present disclosure, when the second overlap transmission time expires, the MAC layer of the target DU may only transmit uplink packets for the target UE to the RLC layer of the target DU. For example, since the uplink destination information for the target UE in the MAC layer of the target DU is updated in step 662, after the second overlap transmission time expires, the MAC layer of the target DU may forward the uplink data for the target UE to the RLC layer of the target DU rather than to the RLC layer of the source DU.

[0133] When the duplicate transmission time expires, at step 670, the electronic device may remove (or delete, release) information about the target UE (e.g., the RLC-transferred UE) from the RLC layer of the source DU. For example, the electronic device may request, instruct, or command the RLC layer of the source DU to delete information about the target UE. For example, the RLC layer of the source DU may delete information about the target UE when the duplicate transmission time set by the electronic device expires.

[0134] In one embodiment of the present disclosure, a UE context (e.g., control information or data packet) for a target UE stored, included or set in an RLC layer of a source DU may be deleted, removed or released based on expiration of both a first redundant transmission time for a downlink direction and a second redundant transmission time for an uplink direction. For example, the electronic device may perform step 670 after both the downlink redundant transmission of the CU and the uplink redundant transmission of the MAC layer of the target DU have expired. For example, the electronic device or the RLC layer of the source DU may wait until both the redundant transmission time of the CU and the redundant transmission time of the MAC layer of the target DU have expired.

[0135] Referring to FIG. 6, the electronic device may repeat at least one of steps 610 to 670 until there is no UE to be transferred to the RLC layer of the target DU. For example, the electronic device may repeat steps 610 to 670 until there is no UE among a plurality of UEs associated with the target cell that has not been transferred from the RLC layer of the source DU to the RLC layer of the target DU.

[0136] If there is no UE to be transferred, in step 680, the electronic device may remove (or delete, release) information related to the transferred target cell from the RLC layer of the source DU. For example, the electronic device may remove cell contexts for the target cell included, stored, or set in the RLC layer of the source DU, or UE contexts for multiple UEs associated with the target cell.

[0137] FIG. 7 is a diagram illustrating an example of data processing in the downlink direction during an RLC layer transfer procedure in one embodiment of the present disclosure.

[0138] In explaining Fig. 7, any explanation that overlaps with the explanation given above in any one of Figs. 1 to 6 may be omitted.

[0139] FIG. 7 may illustrate an example of processing or transmitting / receiving user data in the downlink direction for a target UE (440) when the RLC layer processing the user data in the downlink direction for the target UE (440) is transferred (or changed, switched) from the RLC layer (512) of the source DU (510) to the RLC layer (522) of the target DU (520) in one embodiment of the present disclosure.

[0140] In one embodiment of the present disclosure, the electronic device (or scaling agent module) may control the CU (410) to duplicately transmit downlink packets for the target UE (440) to the source DU (510) and the target DU (520) during the first duplicate transmission time. For example, the electronic device may request, instruct, or command the downlink direction transmission module of the CU (410) to duplicately transmit user data in the downlink direction for the target UE (440) to the RLC layer (512) of the source DU (510) and the RLC layer (522) of the target DU (520). For example, the electronic device may set or start a timer corresponding to the first duplicate transmission time in the downlink direction transmission module of the CU (410). For example, the electronic device may provide or set information about the start, expiration, pause, or end of the first duplicate transmission time to the downlink direction transmission module of the CU (410).

[0141] The CU (410) may transmit user data (e.g., downlink packets) in the downlink direction for the target UE (440) to the source DU (510) and the target DU (520) during the first overlapping transmission time. For example, the CU (410) may transmit the downlink packets for the target UE (440) to the RLC layer (512) of the source DU (510) and the RLC layer (522) of the target DU (520) during the first overlapping transmission time according to a request, instruction, or command of an electronic device (or a scaling agent module). To this end, the CU (410) may duplicate the downlink packets to be transmitted during the first overlapping transmission time and transmit them to both the RLC layer (512) of the source DU (510) and the RLC layer (522) of the target DU (520).

[0142] In one embodiment of the present disclosure, during a first overlapping transmission time, the electronic device can update the downlink destination information of the CU (410) for the target UE (440) from the source DU (510) to the target DU (520). Even if the downlink destination information of the CU (410) for the target UE (440) is set to either the source DU (510) or the target DU (520), during the first overlapping transmission time, the CU (410) can transmit the downlink packet for the target UE (440) to both the source DU (510) and the target DU (520), and the downlink destination information of the CU (410) for the target UE (440) can indicate where the CU (410) will transmit the downlink packet for the target UE (440) outside of the overlapping transmission time. Therefore, after the first duplicate transmission time expires, the CU (410) can transmit the downlink packet for the target UE (440) to the RLC layer (522) of the target DU (520) according to the updated downlink destination information.

[0143] Referring to FIG. 7, the CU (410) may sequentially transmit packets 3 to 8 in the downlink direction to the target UE (440). For example, the CU (410) may transmit packet 3 to the RLC layer (512) of the source DU (510). The CU (410) may duplicate packets 4 to 7 to be transmitted in the downlink direction during the overlapping transmission time and transmit them to the RLC layer (512) of the source DU (510) and the RLC layer (522) of the target DU (520). During the overlapping transmission time, the downlink direction destination information of the CU (410) for the target UE (440) may be updated (or changed, switched) from the RLC layer (512) of the source DU (510) to the RLC layer (522) of the target DU (520). Therefore, after the duplicate transmission time expires or ends, the CU (410) can transmit packet 8 to the RLC layer (522) of the target DU (520) according to the updated downlink direction destination information.

[0144] The RLC layer (512) of the source DU (510) can transmit packets 3 to 7 received from the CU (410) to the target UE (440) through the MAC layer (526), ​​the PHY layer (528), and the RU (430) of the target DU (520). The RLC layer (522) of the target DU (520) can transmit packets 4 to 8 received from the CU (410) to the target UE (440) through the MAC layer (526), ​​the PHY layer (528), and the RU (430) of the target DU (520). The target UE (440) can remove some of the packets received in duplicate. For example, as illustrated in FIG. 7, when the target UE (440) receives packets 4 to 7 in duplicate, the target UE (440) can leave one packet each of packets 4 to 7 and remove the duplicate packets.

[0145] For example, if packet 4 from the RLC layer (512) of the source DU (510) and packet 4 from the RLC layer (522) of the target DU (520) are lost while being transmitted from the RU (430) to the target UE (440), the target UE (440) can transmit a NACK for packet 4 to the RLC layer (522) of the target DU (520), and the RLC layer (522) of the target DU (520) can retransmit packet 4 contained in the packet buffer (524). As illustrated, since the CU (410) transmits packets 4 to 7 repeatedly during the RLC layer transfer procedure, not only the RLC layer (512) of the source DU (510) but also the RLC layer (522) of the target DU (520) includes packet 4, and even if packet 4 is lost in the wireless communication between the RU (430) and the target UE (440), the target UE (440) can receive the lost packet 4 from the RLC layer (522) of the target DU (520). Therefore, according to one embodiment of the present disclosure, it is possible to prevent the occurrence of an RLF due to packet loss during the RLC transfer procedure.

[0146] In one embodiment of the present disclosure, the electronic device can remove information about the target UE (440) from the RLC layer (512) of the source DU (510) after the duplicate transmission time ends or expires. For example, the electronic device can remove or delete a downlink packet for the target UE (440) contained or stored in the packet buffer (514). Accordingly, even if the RLC layer (512) of the source DU (510) does not receive an ACK or NACK from the target UE (440), the electronic device can prevent packet buffer space from being wasted by deleting packets (e.g., packets 3 to 7) for the target UE from the packet buffer (514).

[0147] FIG. 8 is a diagram illustrating an example of data processing in the uplink direction during an RLC layer transfer procedure in one embodiment of the present disclosure.

[0148] In explaining Fig. 8, any explanation that overlaps with the explanation given above in any one of Figs. 1 to 7 may be omitted.

[0149] FIG. 8 may illustrate an example of processing or transmitting / receiving user data in the uplink direction for a target UE (440) when the RLC layer processing the user data in the uplink direction for the target UE (440) is transferred (or changed, switched) from the RLC layer (512) of the source DU (510) to the RLC layer (522) of the target DU (520) in one embodiment of the present disclosure.

[0150] In one embodiment of the present disclosure, the electronic device (or scaling agent module) can control the MAC layer (526) of the target DU (520) to transmit uplink packets for the target UE (440) to the source DU (510) and the target DU (520) in a duplicate manner during the second duplicate transmission time. For example, the electronic device can request, instruct, or command the uplink direction transmission module of the MAC layer (526) of the target DU (520) to transmit user data in the uplink direction for the target UE (440) in a duplicate manner to the RLC layer (512) of the source DU (510) and the RCL layer (522) of the target DU (520). For example, the electronic device can set or start a timer corresponding to the second duplicate transmission time in the uplink direction transmission module of the MAC layer (526) of the target DU (520). For example, the electronic device may provide or set information about the start, expiration, pause, or end of the second overlapping transmission time to the uplink direction transmission module of the MAC layer (526) of the target DU (520).

[0151] The MAC layer (526) of the target DU (520) may transmit user data (e.g., uplink packets) in the uplink direction for the target UE (440) to the source DU (510) and the target DU (520) in duplicate during the second duplicate transmission time. For example, the MAC layer (526) of the target DU (520) may transmit uplink packets for the target UE (440) to the RLC layer (512) of the source DU (510) and the RLC layer (522) of the target DU (520) in duplicate during the second duplicate transmission time, according to a request, instruction, or command of an electronic device (or a scaling agent module). To this end, the MAC layer (526) of the target DU (520) can duplicate the uplink packet to be transmitted during the second overlapping transmission time and transmit it to both the RLC layer (512) of the source DU (510) and the RLC layer (522) of the target DU (520).

[0152] In one embodiment of the present disclosure, during the second overlapping transmission time, the electronic device may update the uplink destination information of the MAC layer (526) of the target DU (520) from the source DU (510) to the target DU (520) for the target UE (440). Even if the uplink destination information for the target UE (440) of the MAC layer (526) of the target DU (520) is set to either the source DU (510) or the target DU (520), during the second overlapping transmission time, the MAC layer (526) of the target DU (520) can transmit the uplink packet for the target UE (440) to both the source DU (510) and the target DU (520), and the uplink destination information for the target UE (440) of the MAC layer (526) of the target DU (520) can indicate where the MAC layer (526) of the target DU (520) will transmit the uplink packet for the target UE (440) at a time other than the overlapping transmission time. Therefore, after the second duplicate transmission time expires, the MAC layer (526) of the target DU (520) can transmit the uplink packet for the target UE (440) to the RLC layer (522) of the target DU (520) according to the updated uplink destination information.

[0153] Referring to FIG. 8, the MAC layer (526) of the target DU (520) can transmit packets 3 to 8 in the uplink direction for the target UE (440). For example, the MAC layer (526) of the target DU (520) can transmit packet 3 to the RLC layer (512) of the source DU (510). The MAC layer (526) of the target DU (520) can duplicate packets 4 to 7 to be transmitted in the uplink direction during the overlap transmission time and transmit them to the RLC layer (512) of the source DU (510) and the RLC layer (522) of the target DU (520). During the overlap transmission time, the uplink direction destination information for the target UE (440) of the MAC layer (526) of the target DU (520) may be updated (or changed, switched) from the RLC layer (512) of the source DU (510) to the RLC layer (522) of the target DU (520). Accordingly, after the overlap transmission time expires or ends, the MAC layer (526) of the target DU (520) may transmit packet 8 to the RLC layer (522) of the target DU (520) according to the updated uplink direction destination information.

[0154] The RLC layer (512) of the source DU (510) can transmit packets 3 to 7 received from the MAC layer (526) of the target DU (520) to the CU (410). The RLC layer (522) of the target DU (520) can transmit packets 4 to 8 received from the MAC layer (526) of the target DU (520) to the CU (410). The CU (410) can remove some of the packets received in duplicate. For example, as illustrated in FIG. 8, when the CU (410) receives packets 4 to 7 in duplicate, it can remove the duplicate packets, leaving only one packet each of packets 4 to 7.

[0155] In one embodiment of the present disclosure, the electronic device can remove information about the target UE (440) from the RLC layer (512) of the source DU (510) after the duplicate transmission time ends or expires. For example, the electronic device can remove or delete an uplink packet for the target UE (440) contained or stored in the packet buffer (514). Accordingly, even if the RLC layer (512) of the source DU (510) does not receive an ACK or NACK from the CU (410), the electronic device can prevent packet buffer space from being wasted by removing packets (e.g., packets 3 to 7) for the target UE from the packet buffer (514).

[0156] FIG. 9 is a drawing showing an example of an operating method of an electronic device according to one embodiment of the present disclosure.

[0157] In explaining Fig. 9, any explanation that overlaps with the explanation given above in any one of Figs. 1 to 8 may be omitted.

[0158] Referring to FIG. 9, an operating method (900) of an electronic device according to one embodiment of the present disclosure may include steps 910 to 940. In one embodiment of the present disclosure, steps 910 to 940 may be executed by at least one processor included in the electronic device. In one embodiment of the present disclosure, steps 910 to 940 may be performed by a scaling agent module included in the electronic device. The operating method (900) of the electronic device is not limited to that illustrated in FIG. 9, and in one or more embodiments, steps not illustrated in FIG. 9 may be further included, or some steps may be omitted.

[0159] In step 910, the electronic device may identify one or more target UEs for transfer from among a plurality of UEs associated with the target cell. In one embodiment of the present disclosure, the electronic device may identify one or more target UEs (e.g., target UEs) for transfer from among the plurality of UEs to which the RLC layer transfer will be performed. For example, the electronic device may determine, select, or screen one or more target UEs from among the plurality of UEs.

[0160] In step 920, the electronic device may set control information for one or more previous target UEs set in the RLC layer of the source DU to the RLC layer of the target DU. For example, the control information for the UE may include user ID (identifier) ​​information, various timer information, window size information for the maximum storage size of a packet, etc. In one embodiment of the present disclosure, the electronic device may replicate the control information for one or more previous target UEs stored, included, or set in the RLC layer of the source DU to the RLC layer of the target DU. For example, the electronic device may control the RLC layer of the source DU to provide the control information for one or more previous target UEs to the RLC layer of the target DU. For example, the electronic device may obtain the control information for one or more previous target UEs stored, included, or set in the RLC layer of the source DU and provide it to the RLC layer of the target DU. In one embodiment of the present disclosure, the electronic device can set control information for one or more previous target UEs in the RLC layer of the target DU based on information used to store, include, or set control information for one or more previous target UEs in the RLC layer of the source DU.

[0161] In step 930, the electronic device may control at least one of the MAC layers of the CU or the target DU to redundantly transmit packets for one or more previous target UEs to the RLC layer of the source DU and the RLC layer of the target DU. For example, the electronic device may transmit information (e.g., an indicator), command, message, or signal to the MAC layer of the CU or the target DU, instructing or requesting redundant transmission for one or more previous target UEs.

[0162] In one embodiment of the present disclosure, the electronic device can control the CU to redundantly transmit downlink packets (e.g., user data in the downlink direction) for one or more previous target UEs to a source DU (e.g., an RLC layer of the source DU) and a target DU (e.g., an RLC layer of the target DU) during a first redundant transmission time. For example, the electronic device can provide the CU with information about the first redundant transmission time. For example, the electronic device can set or start a timer indicating the first redundant transmission time to the CU. For example, the electronic device can set a start time, a duration, an expiration time, or an end time of the first redundant transmission time to the CU.

[0163] In one embodiment of the present disclosure, during a first overlapping transmission time, the CU may transmit downlink packets for one or more previous target UEs to both the source DU and the target DU. For example, even if the downlink destination (e.g., main destination IP) of the CU is set to the RLC layer of the source DU, the CU may transmit downlink packets for one or more previous target UEs to both the source DU and the target DU during the first overlapping transmission time. For example, the CU may duplicate downlink packets for one or more previous target UEs and transmit them to both the RLC layer of the source DU and the RLC layer of the target DU during the first overlapping transmission time.

[0164] In one embodiment of the present disclosure, during a first overlap transmission time, the electronic device can update the downlink destination information of the CU from a source DU (e.g., an RLC layer of the source DU) to a target DU (e.g., an RLC layer of the target DU) for one or more previous target UEs. For example, the electronic device can update the downlink destination of the CU for one or more previous target UEs from the source DU to the target DU during the first overlap transmission time, so that when the first overlap transmission time expires or ends, the CU can forward the downlink packets for the one or more previous target UEs to the RLC layer of the target DU rather than the source DU. Accordingly, based on the expiration (or termination) of the first overlap transmission time, the CU can single-transmit the downlink packets for the one or more previous target UEs to the target DU (e.g., an RLC layer of the target DU).

[0165] In one embodiment of the present disclosure, the electronic device can control the MAC layer of the target DU to overlap transmission of uplink packets (e.g., user data in the uplink direction) for one or more previous target UEs to the RLC layer of the source DU and the RLC layer of the target DU during a second overlap transmission time. For example, the electronic device can provide information about the second overlap transmission time to the MAC layer of the target DU. For example, the electronic device can set or start a timer indicating the second overlap transmission time to the MAC layer of the target DU. For example, the electronic device can set a start time, a duration, an expiration time, or an end time of the second overlap transmission time to the MAC layer of the target DU.

[0166] In one embodiment of the present disclosure, the MAC layer of the target DU may, during the second overlapping transmission time, duplicate transmission of uplink packets for one or more previous target UEs to the RLC layer of the source DU and the RLC layer of the target DU. For example, even if the uplink destination (e.g., main destination IP) of the MAC layer of the target DU is set to the RLC layer of the source DU, the MAC layer of the target DU may, during the second overlapping transmission time, transmit uplink packets for one or more previous target UEs to the RLC layer of the target DU as well as to the RLC layer of the source DU. For example, the MAC layer of the target DU may duplicate uplink packets for one or more previous target UEs and transmit them to both the RLC layer of the source DU and the RLC layer of the target DU during the second overlapping transmission time.

[0167] In one embodiment of the present disclosure, during a second overlap transmission time, the electronic device can update the uplink destination information of the MAC layer of the target DU from the source DU (e.g., the RLC layer of the source DU) to the target DU (e.g., the RLC layer of the target DU) for one or more previous target UEs. For example, during the second overlap transmission time, the electronic device can update the uplink destination of the MAC layer of the target DU for one or more previous target UEs from the RLC layer of the source DU to the RLC layer of the target DU, so that when the second overlap transmission time expires or ends, the MAC layer of the target DU can forward the uplink packets for the one or more previous target UEs to the RLC layer of the target DU rather than to the source DU. Accordingly, based on the expiration (or termination) of the second overlap transmission time, the MAC layer of the target DU can single-transmit the uplink packets for the one or more previous target UEs to the RLC layer of the target DU.

[0168] In one embodiment of the present disclosure, the first overlapping transmission time and the second overlapping transmission time may be the same, different, or overlap. For example, the length of the first overlapping transmission time and the length of the second overlapping transmission time may be the same or different. For example, the start time of the first overlapping transmission time and the start time of the second overlapping transmission time may be the same or different. For example, the end time (or expiration time) of the first overlapping transmission time and the end time (or expiration time) of the second overlapping transmission time may be the same or different.

[0169] In step 940, the electronic device may remove information about one or more previous target UEs from the RLC layer of the source DU. In one embodiment of the present disclosure, the electronic device may remove information about one or more previous target UEs from the RLC layer of the source DU based on expiration of the first overlap transmission time or the second overlap transmission time. For example, the electronic device may remove information about one or more previous target UEs from the RLC layer of the source DU based on (or after) expiration (or termination) of both the first overlap transmission time and the second overlap transmission time. For example, if the first overlap transmission time expires first, the electronic device may remove information about one or more previous target UEs from the RLC layer of the source DU after expiration of the second overlap transmission time. For example, if the second overlap transmission time expires first, the electronic device may remove information about one or more previous target UEs from the RLC layer of the source DU after expiration of the first overlap transmission time.

[0170] An operating method of an electronic device according to an embodiment of the present disclosure may further include steps not illustrated in FIG. 9. For example, the electronic device may remove information about a target cell from an RLC layer of a source DU based on the absence of a UE to be transferred among a plurality of UEs. For example, the electronic device may transfer information about a target cell (e.g., a cell context for the target cell) from a source DU to a target DU, and may transfer information about a plurality of UEs (e.g., UE contexts for the plurality of UEs) from a MAC layer or a PHY layer of the source DU to a MAC layer or a PHY layer of the target DU. For example, before performing step 910, the electronic device may transfer, change, switch, or update a MAC layer that processes user data associated with a target cell from a MAC layer of the source DU to a MAC layer of the target DU. For example, before performing step 910, the electronic device may transfer, change, switch, or update a PHY layer that processes user data associated with a target cell from a PHY layer of the source DU to a PHY layer of the target DU.

[0171] FIG. 10 is a drawing showing an example of an electronic device according to one embodiment of the present disclosure.

[0172] In explaining Fig. 10, any explanation that overlaps with the explanation given above in any one of Figs. 1 to 9 may be omitted.

[0173] The electronic device (1000) illustrated in FIG. 10 may be a server device, which is an electronic device that performs a cell transfer operation from a source DU to a target DU or controls cell transfer from a source DU to a target DU. For example, the electronic device (1000) may be a communication device constituting a RAN, such as a server device that performs an RU function, a server device that performs a DU function, a server device that performs a CU function, a server device that performs an OAM (Operations, Administration, and Maintenance) function, or a separate server device that controls cell transfer (e.g., a scaling agent device, etc.).

[0174] In one embodiment of the present disclosure, the electronic device (1000) may include, but is not limited to, at least one processor (1010) and memory (1020).

[0175] The processor (1010) is electrically connected to components included in the electronic device (1000) and can execute operations or data processing related to control and / or communication of the components included in the electronic device (1000). In one embodiment of the present disclosure, the processor (1010) can 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. In one embodiment of the present disclosure, the processor (1010) can process input data or control other components to process it according to data, operation rules, algorithms, methods, or models stored in the memory (1020). For example, the processor (1010) can perform operations of operation rules, algorithms, methods, modules, or models stored in the memory (1020) using the input data.

[0176] The processor (1010) controls a series of processes to operate the electronic device (1000) according to the above-described embodiments, and may be composed of one or more processors. The one or more processors included in the processor (1010) may be circuitry such as a System on Chip (SoC), an Integrated Circuit (IC), etc. According to one or more embodiments, the processor (1010) may include at least one of a general-purpose processor such as a central processing unit (CPU), a Micro Processor Unit (MPU), 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), an artificial intelligence-only processor such as a neural processing unit (NPU), or a communication-only processor such as a Communication Processor (CP). For example, when the processor (1010) is an artificial intelligence-only processor, the artificial intelligence-only processor may be designed with a hardware structure specialized for processing a specific artificial intelligence model.

[0177] The processor (1010) may include various processing circuits and / or multiple processors. For example, the term "processor" as used in this disclosure, including the claims, may include various processing circuits including at least one processor. One or more of the at least one processor may be configured to perform one or more functions of the present disclosure, individually and / or collectively in a distributed manner. In this disclosure, when "processor," "at least one processor," or "one or more processors" is described as being configured to perform multiple functions, this may include situations where one processor performs some of the functions and other processor(s) perform other parts of the functions, and situations where a single processor performs all of the functions. Furthermore, the at least one processor may include a combination of processors that perform various functions in a distributed manner. The at least one processor may execute program instructions to achieve or perform various functions.

[0178] The memory (1020) is electrically connected to the processor (1010) and may store one or more modules, algorithms, operating rules, models, programs, instructions, or data related to the operation of components included in the electronic device (1000). For example, the memory (1020) may include any non-transitory computer-readable recording medium. For example, the memory (1020) may store one or more modules, algorithms, operating rules, models, programs, instructions, or data for processing and controlling the processor (1010). The memory (1020) may be configured as a storage medium or a combination of storage media such as 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, an optical disk, etc., but is not limited thereto. The memory (1020) may not exist separately and may be configured to be included in the processor (1010). The memory (1020) may be configured as a volatile memory, a nonvolatile memory, or a combination of a volatile memory and a nonvolatile memory.

[0179] In one embodiment of the present disclosure, the memory (1020) may store data and / or information identified, acquired, generated, or determined by the electronic device (1000). For example, the memory (1020) may store data and / or information identified, acquired, generated, or determined by the electronic device (1000) in a compressed form. In one embodiment of the present disclosure, the memory (1020) may store predefined or determined information.

[0180] In one embodiment of the present disclosure, an electronic device (1000) may include a module that performs (or is used to perform) at least one operation. Some modules of the electronic device (1000) that perform at least one operation may be composed of multiple sub-modules or may constitute a single module.

[0181] Some modules that perform at least one operation of the electronic device (1000) may be implemented as hardware modules, software modules, and / or a combination thereof. The memory (1020) may include software modules that perform at least some of the operations of the electronic device (1000) described above. In one embodiment of the present disclosure, the modules included in the memory (1020) may perform operations by being executed by the processor (1010). For example, the modules (i.e., software modules) included in the memory (1020) may include programs, models, or algorithms that are executed according to the control or instructions of the processor (1010) and are configured to perform operations that derive output data for input data.

[0182] The electronic device (1000) may include more components than those illustrated in FIG. 10. In one embodiment of the present disclosure, the electronic device (1000) may further include a communication interface (or communication module) for communicating with another device, server, or system. In one embodiment of the present disclosure, the electronic device (1000) may further include an input / output device and / or an input / output interface.

[0183] In the present disclosure, overlapping descriptions in FIGS. 1 to 10 may be omitted, and one or more embodiments described in FIGS. 1 to 10 may be applied or implemented in combination with each other.

[0184] In the present disclosure, the operations described as being performed by an electronic device may be performed or executed by a module included or stored in the electronic device, or may be performed or executed by at least one processor of the electronic device, or may be performed by at least one processor of the electronic device controlling a module included or stored in the electronic device.

[0185] According to one embodiment of the present disclosure, a packet transmission method for matching (or synchronizing) packet state information between a base station and a user terminal during RLC layer transfer may be provided.

[0186] In one embodiment of the present disclosure, a method of operating an electronic device may include a step of identifying one or more transfer target UEs from among a plurality of UEs (User Equipment) associated with a target cell. In one embodiment of the present disclosure, the method of operating an electronic device may include a step of setting control information for the one or more transfer target UEs, which is set in an RLC layer of a source DU (Distributed Unit), to an RLC layer of a target DU. In one embodiment of the present disclosure, the method of operating an electronic device may include a step of controlling at least one of a Centralized Unit (CU) or a Medium Access Control (MAC) layer of the target DU to transmit packets for the one or more transfer target UEs to an RLC layer of the source DU and an RLC layer of the target DU in duplicate. In one embodiment of the present disclosure, the method of operating an electronic device may include a step of removing information for the one or more transfer target UEs from an RLC layer of the source DU.

[0187] In one embodiment of the present disclosure, the step of controlling at least one of the MAC layers of the CU or the target DU to duplicately transmit packets for the one or more previous target UEs to the RLC layer of the source DU and the RLC layer of the target DU may include the step of controlling the CU to duplicately transmit downlink packets for the one or more previous target UEs to the source DU and the target DU during a first duplicate transmission time.

[0188] In one embodiment of the present disclosure, the method of operating an electronic device may include, during the first overlapping transmission time, updating downlink destination information of the CU from the source DU to the target DU for the one or more previous target UEs.

[0189] In one embodiment of the present disclosure, during the first overlapping transmission time, downlink packets of the CU for the one or more previous target UEs may be transmitted overlappingly to the source DU and the target DU. In one embodiment of the present disclosure, based on the expiration of the first overlapping transmission time, downlink packets of the CU for the one or more previous target UEs may be single-transmitted to the target DU.

[0190] In one embodiment of the present disclosure, the step of removing information about the one or more previous target UEs from the RLC layer of the source DU may include the step of removing information about the one or more previous target UEs from the RLC layer of the source DU based on expiration of the first duplicate transmission time.

[0191] In one embodiment of the present disclosure, the step of controlling at least one of the MAC layers of the CU or the target DU to duplicately transmit packets for the one or more previous target UEs to the RLC layer of the source DU and the RLC layer of the target DU may include the step of controlling the MAC layer of the target DU to duplicately transmit uplink packets for the one or more previous target UEs to the RLC layer of the source DU and the RLC layer of the target DU during a second duplicate transmission time.

[0192] In one embodiment of the present disclosure, the operating method of the electronic device may include, during the second overlapping transmission time, updating, for the one or more previous target UEs, uplink destination information of the MAC layer of the target DU from the RLC layer of the source DU to the RLC layer of the target DU.

[0193] In one embodiment of the present disclosure, during the second overlapping transmission time, uplink packets for the one or more previous target UEs of the MAC layer of the target DU may be overlappingly transmitted to the RLC layer of the source DU and the RLC layer of the target DU. In one embodiment of the present disclosure, based on the expiration of the second overlapping transmission time, uplink packets for the one or more previous target UEs of the MAC layer of the target DU may be single-transmitted to the RLC layer of the target DU.

[0194] In one embodiment of the present disclosure, the step of removing information about the one or more previous target UEs from the RLC layer of the source DU may include the step of removing information about the one or more previous target UEs from the RLC layer of the source DU based on expiration of the second duplicate transmission time.

[0195] In one embodiment of the present disclosure, a method of operating an electronic device may include a step of removing information about the target cell from an RLC layer of the source DU based on the absence of a UE to be transferred among the plurality of UEs.

[0196] In one embodiment of the present disclosure, a method of operating an electronic device may include a step of transferring information about the target cell from the source DU to the target DU. In one embodiment of the present disclosure, the method of operating an electronic device may include a step of transferring information about the plurality of UEs from a MAC layer or a PHY layer of the source DU to a MAC layer or a PHY layer of the target DU.

[0197] In one embodiment of the present disclosure, a program for performing the above-described method on a computer can be recorded on a computer-readable recording medium.

[0198] In one embodiment of the present disclosure, an electronic device may include a memory that stores one or more instructions and at least one processor that executes the one or more instructions. In one embodiment of the present disclosure, when the at least one processor executes the one or more instructions, the electronic device may identify one or more transfer target UEs from among a plurality of UEs associated with a target cell. In one embodiment of the present disclosure, when the at least one processor executes the one or more instructions, the electronic device may set control information for the one or more transfer target UEs set in the RLC layer of the source DU to the RLC layer of the target DU. In one embodiment of the present disclosure, when the at least one processor executes the one or more instructions, the electronic device may control at least one of a CU or a MAC layer of the target DU to redundantly transmit packets for the one or more transfer target UEs to the RLC layer of the source DU and the RLC layer of the target DU. In one embodiment of the present disclosure, when the at least one processor executes the one or more instructions, the electronic device may remove information for the one or more transfer target UEs from the RLC layer of the source DU.

[0199] In one embodiment of the present disclosure, the electronic device can control the CU to duplicately transmit downlink packets for the one or more previous target UEs to the source DU and the target DU during a first duplicate transmission time by having at least one processor execute one or more instructions.

[0200] In one embodiment of the present disclosure, the electronic device can update the downlink destination information of the CU from the source DU to the target DU for the one or more previous target UEs during the first overlapping transmission time by having the at least one processor execute the one or more commands.

[0201] In one embodiment of the present disclosure, the electronic device can remove information about the one or more previous target UEs from the RLC layer of the source DU based on expiration of the first duplicate transmission time by the at least one processor executing the one or more commands.

[0202] In one embodiment of the present disclosure, the electronic device can control the MAC layer of the target DU to repeatedly transmit uplink packets for the one or more previous target UEs to the RLC layer of the source DU and the RLC layer of the target DU during the second overlapping transmission time by the at least one processor executing the one or more commands.

[0203] In one embodiment of the present disclosure, the electronic device can update, during the second overlapping transmission time, uplink destination information of the MAC layer of the target DU from the RLC layer of the source DU to the RLC layer of the target DU, for the one or more previous target UEs, by the at least one processor executing the one or more commands.

[0204] In one embodiment of the present disclosure, the electronic device can remove information about the one or more previous target UEs from the RLC layer of the source DU based on the expiration of the second duplicate transmission time by the at least one processor executing the one or more commands.

[0205] In one embodiment of the present disclosure, the electronic device can remove information about the target cell from the RLC layer of the source DU based on the absence of a UE to be transferred among the plurality of UEs by the at least one processor executing the one or more commands.

[0206] In one embodiment of the present disclosure, the electronic device can transfer information about the target cell from the source DU to the target DU by the at least one processor executing the one or more commands. In one embodiment of the present disclosure, the electronic device can transfer information about the plurality of UEs from the MAC layer or PHY layer of the source DU to the MAC layer or PHY layer of the target DU by the at least one processor executing the one or more commands.

[0207] 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.

[0208] 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. In the operating method of an electronic device (1000), A step (910) of identifying one or more previous target UEs among a plurality of UEs (User Equipment) associated with a target cell; A step (920) of setting control information for one or more previous target UEs set in the RLC (Radio link Control) layer of the source DU (Distributed Unit) to the RLC layer of the target DU; Step (930) of controlling at least one of the CU (Centralized Unit) or the MAC (Medium Access Control) layer of the target DU to transmit packets for the one or more previous target UEs to the RLC layer of the source DU and the RLC layer of the target DU in duplicate; and A method comprising the step (940) of removing information about said one or more previous target UEs from the RLC layer of said source DU.

2. In paragraph 1, A step for controlling at least one of the MAC layers of the CU or the target DU to transmit packets for the one or more previous target UEs to the RLC layer of the source DU and the RLC layer of the target DU in duplicate, A method comprising the step of controlling the CU to transmit downlink packets for the one or more previous target UEs to the source DU and the target DU during the first overlapping transmission time.

3. In paragraph 2, A method comprising, during the first overlapping transmission time, updating the downlink destination information of the CU from the source DU to the target DU for the one or more previous target UEs.

4. In paragraph 2 or 3, During the first overlapping transmission time, downlink packets for the one or more previous target UEs of the CU are overlappingly transmitted to the source DU and the target DU, A method wherein, based on the expiration of the first duplicate transmission time, the downlink packets of the CU for the one or more previous target UEs are single-transmitted to the target DU.

5. In any one of paragraphs 2 to 4, The step of removing information about one or more previous target UEs from the RLC layer of the source DU is: A method comprising the step of removing information about the one or more previous target UEs from the RLC layer of the source DU based on expiration of the first duplicate transmission time.

6. In any one of paragraphs 1 to 5, A step for controlling at least one of the MAC layers of the CU or the target DU to transmit packets for the one or more previous target UEs to the RLC layer of the source DU and the RLC layer of the target DU in duplicate, A method comprising the step of controlling the MAC layer of the target DU to duplicately transmit uplink packets for the one or more previous target UEs to the RLC layer of the source DU and the RLC layer of the target DU during the second duplicate transmission time.

7. In paragraph 6, A method comprising, during the second overlapping transmission time, updating, for the one or more previous target UEs, uplink destination information of the MAC layer of the target DU from the RLC layer of the source DU to the RLC layer of the target DU.

8. In paragraph 6 or 7, During the second overlapping transmission time, the uplink packets for the one or more previous target UEs of the MAC layer of the target DU are overlappingly transmitted to the RLC layer of the source DU and the RLC layer of the target DU, A method wherein, based on the expiration of the second duplicate transmission time, the uplink packets for the one or more previous target UEs of the MAC layer of the target DU are single-transmitted to the RLC layer of the target DU.

9. In any one of paragraphs 6 to 8, The step of removing information about one or more previous target UEs from the RLC layer of the source DU is: A method comprising the step of removing information about said one or more previous target UEs from the RLC layer of said source DU based on expiration of said second duplicate transmission time.

10. In any one of paragraphs 1 to 9, A method comprising the step of removing information about the target cell from the RLC layer of the source DU based on the absence of a UE to be transferred among the plurality of UEs.

11. In any one of paragraphs 1 to 10, a step of transferring information about the target cell from the source DU to the target DU; and A method comprising the step of transferring information about the plurality of UEs from the MAC layer or PHY layer of the source DU to the MAC layer or PHY layer of the target DU.

12. A computer-readable recording medium having recorded thereon a program for performing the method of any one of claims 1 to 11 on a computer.

13. In an electronic device (1000), A memory (1020) storing one or more instructions; and At least one processor (1010) for executing one or more of the above instructions, The electronic device (1000) executes the one or more instructions by the at least one processor (1010), Identify one or more previous target UEs among multiple UEs associated with the target cell, Set control information for one or more of the previous target UEs set in the RLC layer of the source DU in the RLC layer of the target DU, Controlling at least one of the MAC layers of the CU or the target DU to transmit packets for the one or more previous target UEs to the RLC layer of the source DU and the RLC layer of the target DU in duplicate; An electronic device that removes information about one or more previous target UEs from the RLC layer of the source DU.

14. In paragraph 13, The electronic device (1000) executes the one or more instructions by the at least one processor (1010), An electronic device that controls the CU to transmit downlink packets for the one or more previous target UEs to the source DU and the target DU during the first overlapping transmission time.

15. In paragraph 13 or 14, The electronic device (1000) executes the one or more instructions by the at least one processor (1010), An electronic device that controls the MAC layer of the target DU to duplicately transmit uplink packets for the one or more previous target UEs to the RLC layer of the source DU and the RLC layer of the target DU during the second duplicate transmission time.

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