Method and apparatus for transmitting and receiving data in wireless communication system

Abstract

Provided is a method performed by a user equipment (UE) in a wireless communication system, the method comprising: receiving a radio resource control (RRC) message; identifying whether a complete configuration indicator exists in the RRC message; in a case where there is no complete configuration indicator in the RRC message, not releasing configuration information of a service data adaptation protocol (SDAP) layer and a new radio (NR) packet data convergence protocol (PDCP) layer configured in a source base station (BS); and reusing configuration information of the SDAP layer and the NR PDCP layer configured in the source BS for the target BS based on the identification that the complete configuration indicator does not exist in the RRC message.

Description

[0001] This case is a divisional application of the invention patent application with the application date of February 10, 2020, application number 202080014087.1, and invention name “Method and device for sending and receiving data in a wireless communication system”. Technical Field

[0002] The present disclosure relates to a method and apparatus for transmitting and receiving data in a wireless communication system. More specifically, the present disclosure relates to a method and apparatus for effectively maintaining header compression configuration information in a wireless communication system. In addition, the present disclosure relates to a method and apparatus for effectively performing handover between radio access technologies in a wireless communication system. Background Art

[0003] In order to meet the increased demand for wireless data traffic after the commercialization of the fourth generation (4G) communication system, considerable efforts have been made to develop the pre-fifth generation (5G) communication system or 5G communication system. This is one of the reasons why the "5G communication system" or "pre-5G communication system" is called "beyond the 4G network communication system" or "post-long term evolution (LTE) system". In order to achieve high data transmission rates, the 5G communication system is being developed to be implemented in ultra-high frequency bands (millimeter waves (mmWave)) (for example, 60GHz band). In order to reduce the path loss of radio waves in such ultra-high frequency bands and increase the transmission distance of radio waves in 5G communication systems, various technologies have been discussed and studied, such as: beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming and massive antennas. In order to improve the system network for 5G communication system, various technologies have been developed, such as: evolved small cell, advanced small cell, cloud radio access network (Cloud-RAN), ultra-dense network, device-to-device communication (D2D), wireless backhaul, mobile network, cooperative communication, coordinated multi-point (CoMP) and interference cancellation. In addition, for 5G communication system, other technologies have been developed, such as hybrid frequency shift keying (FSK) and orthogonal amplitude modulation (QAM) (FQAM) and sliding window superposition coding (SWSC) as advanced coding modulation (ACM) schemes, and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access schemes.

[0004] The Internet has evolved from a human-based connected network where humans create and consume information to the Internet of Things (IoT), in which distributed configurations such as objects exchange information with each other to process information. Internet of Everything (IoE) technology is emerging, in which technologies related to IoT are combined with technologies for processing big data, such as by connecting to cloud servers. In order to realize IoT, various technical components are required, such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, security technology, etc. In recent years, various technologies have been studied, including sensor networks for connecting objects, machine-to-machine (M2M) communication, machine type communication (MTC), etc. In the IoT environment, intelligent Internet Technology (IT) services can be provided to collect and analyze data obtained from interconnected objects, thereby creating new value for human life. As existing information technology (IT) technologies are integrated and combined with various industries, IoT can be applied to various fields, such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, health care, smart home appliances, high-quality medical services, etc.

[0005] Various attempts are being made to apply 5G communication systems to IoT networks. For example, technologies related to sensor networks, M2M communications, MTC, etc. are being implemented by using 5G communication technologies including beamforming, MIMO, array antennas, etc. The application of Cloud-RAN as a big data processing technology as described above can be an example of the fusion of 5G communication technology and IoT technology.

[0006] As described above, due to the development of wireless communication systems, various services can be provided, and thus a method of smoothly providing such services is required. Summary of the invention

[0007] According to an embodiment of the present disclosure, an operation method of a user equipment (UE) in a wireless communication system, the operation method comprising: receiving a radio resource control (RRC) message including packet data convergence protocol (PDCP) layer configuration information for each data radio bearer (DRB) from a base station; and, if a PDCP entity of at least one DRB is configured to be reestablished, and if at least one DRB is configured with the PDCP layer configuration information including an indicator indicating continuous use of a header compression protocol configuration, indicating to a lower layer entity that the header compression protocol configuration information for at least one DRB is configured to be continuously used.

[0008] According to an embodiment of the present disclosure, a method for performing switching between different wireless access technologies performed by a user equipment (UE) in wireless communication includes: receiving a radio resource control (RRC) message; identifying whether there is a complete configuration indicator in the RRC message; in the absence of a complete configuration indicator in the RRC message, not releasing the configuration information of the service data adaptation protocol (SDAP) layer and the new radio (NR) packet data convergence protocol (PDCP) layer configured in the source base station (BS); and based on the identification that there is no complete configuration indicator in the RRC message, reusing the configuration information of the SDAP layer and the NR PDCP layer configured in the source BS for the target BS.

[0009] According to an embodiment of the present disclosure, a method for performing switching between different wireless access technologies performed by a user equipment (UE) in wireless communication includes: receiving a radio resource control (RRC) message; identifying whether there is a complete configuration indicator in the RRC message; in the absence of a complete configuration indicator in the RRC message, not releasing the configuration information of the service data adaptation protocol (SDAP) layer and the new radio (NR) packet data convergence protocol (PDCP) layer configured in the source base station (BS); and based on the identification that there is no complete configuration indicator in the RRC message, reusing the configuration information of the SDAP layer and the NR PDCP layer configured in the source BS for the target BS.

[0010] According to an embodiment of the present disclosure, a user equipment (UE) in wireless communication for performing switching between different wireless access technologies includes: a transceiver; a memory storing one or more instructions; and at least one processor configured to execute the one or more instructions to: receive a radio resource control (RRC) message; identify whether there is a complete configuration indicator in the RRC message; in the absence of a complete configuration indicator in the RRC message, not release the configuration information of the service data adaptation protocol (SDAP) layer and the new radio (NR) packet data convergence protocol (PDCP) layer configured in the source base station (BS); and based on the identification that there is no complete configuration indicator in the RRC message, reuse the configuration information of the SDAP layer and the NR PDCP layer configured in the source BS for the target BS.

[0011] According to an embodiment of the present disclosure, a method for performing switching between different radio access technologies performed by a source base station (BS) in wireless communication includes: sending a radio resource control (RRC) message to a user equipment (UE), wherein a complete configuration indicator is present or absent in the RRC message, wherein the complete configuration indicator is associated with whether the UE releases or does not release the configuration information of the service data adaptation protocol (SDAP) layer and the new radio (NR) packet data convergence protocol (PDCP) layer configured in the source BS, and wherein the complete configuration indicator is associated with whether the UE reuses the configuration information of the SDAP layer and the NR PDCP layer configured in the source BS for the target BS.

[0012] According to an embodiment of the present disclosure, a source base station (BS) in a wireless communication for performing switching between different wireless access technologies, the source BS comprising: a transceiver; a memory storing one or more instructions; and at least one processor configured to execute the one or more instructions to: send a radio resource control (RRC) message to a user equipment (UE), wherein a complete configuration indicator is present or absent in the RRC message, wherein the complete configuration indicator is associated with whether the UE releases or does not release the configuration information of the service data adaptation protocol (SDAP) layer and the new radio (NR) packet data convergence protocol (PDCP) layer configured in the source BS, and wherein the complete configuration indicator is associated with whether the UE reuses the configuration information of the SDAP layer and the NR PDCP layer configured in the source BS for the target BS. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, wherein like reference numerals represent like parts:

[0014] Figure 1A A schematic diagram showing the structure of a long term evolution (LTE) system according to an embodiment of the present disclosure;

[0015] Figure 1B A schematic diagram showing a radio protocol architecture in an LTE system according to an embodiment of the present disclosure;

[0016] Figure 1C A schematic diagram showing the structure of a next generation wireless communication system according to an embodiment of the present disclosure;

[0017] Figure 1D A schematic diagram showing the structure of a next generation wireless communication system according to an embodiment of the present disclosure;

[0018] Figure 1E A schematic diagram showing the structure of a next generation wireless communication system according to an embodiment of the present disclosure;

[0019] Figure 1F A schematic diagram showing a radio protocol architecture of a next generation wireless communication system according to an embodiment of the present disclosure;

[0020] Figure 1G A schematic diagram showing a radio resource control (RRC) mode of a user equipment (UE) belonging to a next generation wireless communication system and a conversion relationship between the modes according to an embodiment of the present disclosure is shown;

[0021] Figure 1H A schematic diagram for describing a process of establishing a connection between a UE and a network according to an embodiment of the present disclosure is shown;

[0022] Fig. 1I A schematic diagram for describing a Robust Header Compression (ROHC) protocol according to an embodiment of the present disclosure is shown;

[0023] Figure 1J A schematic diagram for describing a data processing process of a sending packet data convergence protocol (PDCP) layer and a receiving PDCP layer according to an embodiment of the present disclosure is shown;

[0024] Figure 1K A schematic diagram for describing a handover process in a next generation wireless communication system according to an embodiment of the present disclosure is shown;

[0025] Figure 1L A schematic diagram for describing a process of restoring a connection by a UE in an RRC inactive mode according to an embodiment of the present disclosure is shown;

[0026] Figure 1M A schematic diagram showing the operation of a UE according to an embodiment of the present disclosure;

[0027] Figure 1N A schematic diagram showing the structure of a UE according to an embodiment of the present disclosure;

[0028] Fig.1O A schematic diagram showing a structure of an electronic device for supporting conventional network communication and fifth generation (5G) network communication according to an embodiment of the present disclosure is shown;

[0029] Figure 1P A block diagram showing the structure of a base station in a wireless communication system according to an embodiment of the present disclosure;

[0030] Figure 2A A schematic diagram showing the structure of an LTE system according to an embodiment of the present disclosure;

[0031] Figure 2B A schematic diagram showing a radio protocol architecture in an LTE system according to an embodiment of the present disclosure;

[0032] Figure 2CA schematic diagram showing the structure of a next generation wireless communication system according to an embodiment of the present disclosure;

[0033] Figure 2D A schematic diagram showing a radio protocol architecture of a next generation wireless communication system according to an embodiment of the present disclosure;

[0034] Figure 2E A schematic diagram showing an RRC mode of a UE belonging to a next generation wireless communication system and a conversion relationship between modes according to an embodiment of the present disclosure is shown;

[0035] Figure 2F A schematic diagram for describing a process in which a UE establishes a connection with a network by transitioning from an RRC idle mode or an RRC inactive mode to an RRC connected mode according to an embodiment of the present disclosure is shown;

[0036] Figure 2G A schematic diagram for describing a handover process in a next generation wireless communication system according to an embodiment of the present disclosure is shown;

[0037] Figure 2H A schematic diagram for describing a conditional switching process in a next generation wireless communication system according to an embodiment of the present disclosure is shown;

[0038] Fig.2I A schematic diagram of a first embodiment for describing operations of a base station in a handover situation between different radio access technologies according to an embodiment of the present disclosure is shown.

[0039] Figure 2J A schematic diagram showing a second embodiment for describing the operation of a base station in a handover situation between different radio access technologies according to an embodiment of the present disclosure;

[0040] Figure 2K A schematic diagram showing the operation of a UE according to an embodiment of the present disclosure;

[0041] Figure 2L A schematic diagram showing the structure of a UE according to an embodiment of the present disclosure;

[0042] Figure 2M A schematic diagram showing a structure of an electronic device for supporting traditional network communication and 5G network communication according to an embodiment of the present disclosure is shown; and

[0043] Figure 2N A block diagram showing the structure of a base station in a wireless communication system according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0044] A method and apparatus for effectively maintaining header compression configuration information in a wireless communication system are provided. In addition, a method and apparatus for effectively performing handover between radio access technologies in a wireless communication system are provided. However, the technical problems of the present disclosure are not limited to the above technical features, and other unexplained technical problems can be inferred from the following embodiments.

[0045] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the presented embodiments of the disclosure.

[0046] According to an embodiment of the present disclosure, a method for operating a user equipment (UE) in a wireless communication system includes: receiving a radio resource control (RRC) message including packet data convergence protocol (PDCP) layer configuration information for each data radio bearer (DRB) from a base station; and, if the PDCP entity of at least one DRB is configured to be reestablished, and if at least one DRB is configured with the PDCP layer configuration information including an indicator indicating continuous use of a header compression protocol configuration, indicating to a lower layer entity that the header compression protocol configuration information for at least one DRB is configured to be used continuously.

[0047] Prior to proceeding with the following description, it may be helpful to set forth definitions of certain words and phrases used throughout this patent document: the terms "include" and "comprise," and their derivatives, mean including but not limited to; the term "or" is inclusive, meaning and / or; the phrases "associated with" and "associated therewith," and their derivatives may mean including, included within, interconnected with, containing, contained within, connected to or connected with, coupled to or coupled with, communicable with, cooperating with, interleaved with, juxtaposed with, proximate to, bound to or bound with, having, having properties of, and the like; and the term "controller" means any device, system, or portion thereof that controls at least one operation, such device may be implemented in hardware, firmware, or software, or some combination of at least two thereof. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

[0048] In addition, the various functions described below can be implemented or supported by one or more computer programs, each of which is formed by a computer-readable program code and embodied in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, processes, functions, objects, classes, instances, related data or parts thereof suitable for implementation in a suitable computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code and executable code. The term "computer-readable medium" includes any type of medium that can be accessed by a computer, such as a read-only memory (ROM), a random access memory (RAM), a hard drive, a compact disk (CD), a digital video disk (DVD) or any other type of memory. "Non-transitory" computer-readable media do not include wired, wireless, optical or other communication links that transmit temporary electrical signals or other signals. Non-transitory computer-readable media include media that can permanently store data and media that can store and rewrite data later, such as rewritable optical disks or erasable memory devices.

[0049] Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.

[0050] Discussed below Figures 1A to 2N The various embodiments used to describe the principles of the present disclosure in this patent document are for illustration only and should not be interpreted in any way as limiting the scope of the present disclosure. Those skilled in the art will appreciate that the principles of the present disclosure can be implemented in any appropriately arranged system or device.

[0051] Throughout the disclosure, the expression "at least one of a, b, and c" means only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof.

[0052] Examples of the terminal may include a User Equipment (UE), a Mobile Station (MS), a cellular phone, a smart phone, a computer, and a multimedia system capable of performing a communication function.

[0053] In this disclosure, a controller may also be referred to as a processor.

[0054] Throughout the specification, a layer (or a layer arrangement) may also be referred to as an entity.

[0055] Hereinafter, the operating principle of the present disclosure will be described with reference to the accompanying drawings. While describing the present disclosure, detailed descriptions of related well-known functions or configurations may be omitted when it is considered that they may unnecessarily confuse the essence of the present disclosure. In addition, the terms used below are defined in consideration of the functions in the present disclosure, and may have different meanings depending on the intention, habits, etc. of the user or operator. Therefore, the terms should be defined based on the description of the entire specification.

[0056] For the same reason, for the sake of clarity, components may be exaggerated, omitted or schematically shown in the drawings. In addition, the size of each component does not fully reflect the actual size. In the drawings, similar reference numerals represent similar elements.

[0057] By referring to the following detailed description and the accompanying drawings of the embodiments of the present disclosure, the advantages and features of one or more embodiments of the present disclosure and the methods for achieving the same advantages and features can be more easily understood. In this regard, the embodiments presented in the present disclosure may have different forms and should not be interpreted as being limited to the descriptions set forth herein. On the contrary, these embodiments of the present disclosure are provided to make the present disclosure detailed and complete, and to fully convey the concepts of the embodiments presented in the present disclosure to those of ordinary skill in the art, and the present disclosure will only be limited by the appended claims.

[0058] Here, it will be understood that the combination of blocks in a flowchart or process flow diagram can be performed by computer program instructions. Because these computer program instructions can be loaded into a processor of a general-purpose computer, a special-purpose computer, or another programmable data processing device, the instructions executed by the processor of the computer or another programmable data processing device create units for performing the functions described in the (multiple) flowchart blocks. The computer program instructions can be stored in a computer-usable or computer-readable memory that can guide the computer or another programmable data processing device to implement the functions in a specific manner, so the instructions stored in the computer-usable or computer-readable memory can also produce a manufacturing item containing instruction units for performing the functions described in the (multiple) flowchart blocks. The computer program instructions can also be loaded into a computer or another programmable data processing device, so that when a series of operations are performed in the computer or another programmable data processing device, the instructions for operating the computer or another programmable data processing device by generating a computer-executed process can provide operations for performing the functions described in the (multiple) flowchart blocks.

[0059] In addition, each block may represent a module, a fragment or a portion of code including one or more executable instructions for performing (multiple) specific logical functions. It should also be noted that in some alternative implementations, the functions mentioned in the blocks may appear out of order. For example, two blocks shown in succession may actually be executed substantially in parallel, or sometimes the blocks may be executed in reverse order according to the corresponding functions.

[0060] Here, the term "unit" in the embodiment of the present disclosure refers to a software component or hardware component such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and performs a specific function. However, the term "unit" is not limited to software or hardware. A "unit" can be formed in an addressable storage medium, or can be formed to operate one or more processors. Therefore, for example, the term "unit" can refer to components such as software components, object-oriented software components, class components, and task components, and can include processes, functions, attributes, procedures, subroutines, program code fragments, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays, or variables. The functions provided by components and "units" can be associated with a smaller number of components and "units", or can be divided into additional components and "units". In addition, components and "units" can be embodied as one or more central processing units (CPUs) for reproducing devices or secure multimedia cards. In addition, in an embodiment, a "unit" can include at least one processor.

[0061] Hereinafter, embodiments of the present disclosure will be described in conjunction with the accompanying drawings.

[0062] In addition, for the convenience of description, the terms used in this document for identifying access nodes, terms representing network entities, terms representing messages, terms representing interfaces between network entities, terms representing various types of identification information, etc. are exemplified. Therefore, the terms used in the present disclosure are not restrictive, and other terms representing targets having the same technical meaning may be used.

[0063] In the following, for the convenience of description, the present disclosure uses the terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) standard. However, the present disclosure is not limited by such terms and names and can be equally applied to systems conforming to other standards. In the present disclosure, for the convenience of description, evolved Node B (eNB) will be used interchangeably with next generation Node B (gNB). In other words, a base station described as an eNB may also indicate a gNB.

[0064] In the next generation wireless communication system, the Packet Data Convergence Protocol (PDCP) layer may use a header compression protocol (e.g., Robust Header Compression (ROHC)) for compressing headers. However, in order to apply the header compression protocol, the transmitting PDCP layer and the receiving PDCP layer need to exchange and synchronize header compression protocol information (e.g., ROHC context). When the header compression protocol information is re-exchanged and synchronized whenever a handover is performed, transmission resources are wasted and the start of the header compression application is delayed.

[0065] In the present disclosure, according to the instruction of the base station, during the handover, the header compression protocol information that is exchanged and synchronized to apply the header compression protocol can be used unchanged by the target base station, so that unnecessary waste of transmission resources and delay in the application of header compression can be prevented. In addition, in the present disclosure, when an indicator that enables the header compression protocol information to be used unchanged is defined, the indicator is not defined for each UE, but is defined for each bearer, so that the indicator indicates differently for each bearer configured in the UE. In addition, the existing header compression protocol information can be reused by using the indicator not only during the handover but also when the UE reestablishes a connection in the radio resource control (RRC) inactive mode.

[0066] In particular, according to some embodiments of the present disclosure, since the header compression protocol (e.g., ROHC) may be a function set in the PDCP layer, the configuration information of the header compression protocol (e.g., ROHC context) is not initialized during handover or RRC connection recovery, and an indicator indicating whether to use the existing header compression protocol configuration information unchanged or to reuse the existing header compression protocol configuration information may be defined in the PDCP layer configuration information (pdcp-config). In addition, as described above, when the continuous use indicator of the header compression protocol configuration information (drb-ContinueROHC) is defined for each bearer in the PDCP layer configuration information, it is possible to indicate whether to use the header compression protocol configuration information continuously for each bearer of the UE (rather than for each UE), which may increase the degree of freedom of implementation of the base station. In addition, the continuous use indicator of the header compression protocol configuration information (drb-ContinueROHC) may be an indicator for a one-time indication. For example, the header compression protocol configuration information continuous use indicator (drb-ContinueROHC) is an indicator indicating whether to continue to use the header compression protocol configuration information as it is or to initialize the header compression protocol configuration information at the time of handover or at the time of RRC connection recovery, so the stored header compression protocol configuration information continuous use indicator (drb-ContinueROHC) may not be applied during the next handover or the next RRC connection recovery. In other words, the header compression protocol configuration information continuous use indicator (drb-ContinueROHC) may be reconfigured whenever a handover or RRC connection recovery occurs.

[0067] In addition, according to some embodiments of the present disclosure, when the UE restores the RRC connection, only other (pieces of) configuration information except the above-mentioned header compression protocol configuration information continuous use indicator (drb-ContinueROHC) can be reconstructed when the stored PDCP layer configuration information is reconstructed. Therefore, when the base station configures the header compression protocol configuration information continuous use indicator (drb-ContinueROHC) in the RRC message sent to the UE, the UE can reconstruct the previous header compression protocol configuration information continuous use indicator (drb-ContinueROHC) among the stored PDCP layer configuration information, and does not rewrite the reconfigured header compression protocol configuration information continuous use indicator (drb-ContinueROHC).

[0068] Hereinafter, operations of a UE according to an embodiment of the present disclosure are proposed.

[0069] Figure 1A A schematic diagram showing the structure of a Long Term Evolution (LTE) system according to an embodiment of the present disclosure.

[0070] refer to Figure 1A , a radio access network (RAN) of an LTE system may include evolved base stations (e.g., eNBs or NBs) 1a-05, 1a-10, 1a-15, and 1a-20, a mobility management entity (MME) 1a-25, and a serving gateway (S-GW) 1a-30. A user equipment (UE) or terminal 1a-35 may access an external network via eNBs 1a-05, 1a-10, 1a-15, or 1a-20 and S-GW 1a-30.

[0071] exist Figure 1A In the present invention, each of eNB 1a-05, 1a-10, 1a-15 and 1a-20 can correspond to an existing NB of a universal mobile telecommunications system (UMTS). eNB 1a-05, 1a-10, 1a-15 or 1a-20 can be connected to UE1a-35 through a radio channel, and can perform complex functions compared to existing NBs. Because all user service data including real-time services such as Internet phone (VoIP) are served through shared channels in the LTE system, an entity is required for collating the buffer status information, available transmission power status information, channel status information, etc. of the UE and performing scheduling, and each of eNB 1a-05, 1a-10, 1a-15 and 1a-20 serves as such an entity. A single eNB can generally control multiple cells. For example, the LTE system can achieve a data rate of 100Mbps using a radio access technology such as orthogonal frequency division multiplexing (OFDM) at a bandwidth of 20MHz. The LTE system can also use adaptive modulation and coding (AMC) to determine the modulation scheme and channel coding rate according to the channel state of the UE 1a-35. The S-GW 1a-30 is an entity for providing data bearers, and can configure or release data bearers under the control of the MME 1a-25. The MME 1a-25 is an entity for performing mobility management functions and various control functions for the UE 1a-35, and can be connected to the eNBs 1a-05, 1a-10, 1a-15, and 1a-20.

[0072] Figure 1B A schematic diagram showing a radio protocol architecture in an LTE system according to an embodiment of the present disclosure.

[0073] refer to Figure 1B, the radio protocol architecture of the LTE system may include packet data convergence protocol (PDCP) layers 1b-05 and 1b-40, radio link control (RLC) layers 1b-10 and 1b-35, and medium access control (MAC) layers 1b-15 and 1b-30 for UE and eNB, respectively. The PDCP layer 1b-05 or 1b-40 is responsible for IP header compression / decompression, etc. The main functions of the PDCP layer 1b-05 or 1b-40 can be summarized as follows.

[0074] -Header compression and decompression: ROHC only

[0075] -Transmission of user data

[0076] - For RLC AM, in-sequence delivery of upper layer PDUs during PDCP re-establishment

[0077] - For split bearers in DC (supported only for RLC AM): PDCP PDU routing for transmission and PDCP PDU reordering for reception

[0078] - For RLC AM, repeat detection of lower layer SDUs during PDCP re-establishment

[0079] - PDCP SDU retransmission at handover for split bearers in DC, and PDCP PDU retransmission during PDCP data recovery for RLC AM,

[0080] -Encryption and decryption

[0081] - Timer-based SDU discard in uplink

[0082] The RLC layer 1b-10 or 1b-35 may perform, for example, an automatic repeat request (ARQ) operation by reconfiguring the PDCP PDU to an appropriate size. The main functions of the RLC layer 1b-10 or 1b-35 may be summarized as follows.

[0083] -Transmission of upper layer PDU

[0084] - Error correction via ARQ (for AM data transmission only)

[0085] - Concatenation, segmentation and reassembly of RLC SDUs (for UM and AM data transport only)

[0086] - Re-segmentation of RLC data PDU (for AM data transmission only)

[0087] - Reorder RLC data PDUs (only for UM and AM data transmission)

[0088] - Duplicate detection (for UM and AM data transmission only)

[0089] -Protocol error detection (for AM data transmission only)

[0090] -RLC SDU discard (only for UM and AM data transmission)

[0091] -RLC re-establishment

[0092] The MAC layer 1b-15 or 1b-30 is connected to a plurality of RLC layers configured for a single UE and can multiplex RLC PDUs to and demultiplex RLC PDUs from the MAC PDUs. The main functions of the MAC layer 1b-15 or 1b-30 can be summarized as follows.

[0093] - Mapping between logical channels and transport channels

[0094] - Multiplex MAC SDUs belonging to one or different logical channels into TBs delivered to the physical layer on the transport channel / demultiplex MAC SDUs belonging to one or different logical channels from TBs from the physical layer on the transport channel

[0095] -Dispatch information report

[0096] - Error correction via HARQ

[0097] - Priority handling between logical channels of a UE

[0098] - Priority handling between UEs through dynamic scheduling

[0099] -MBMS service identification

[0100] -Transmission format selection

[0101] -filling

[0102] The physical (PHY) layer 1b-20 or 1b-25 may channel-code and modulate upper layer data into OFDM symbols and transmit the OFDM symbols through a radio channel, or demodulate OFDM symbols received through a radio channel and channel-decode the OFDM symbols and deliver them to an upper layer.

[0103] Figure 1C A schematic diagram showing the structure of a next generation wireless communication system according to an embodiment of the present disclosure.

[0104] refer to Figure 1C, the RAN of a next-generation wireless communication system (e.g., a new radio (NR) or 5G system) may include a new radio node B (NR NB) or a new radio next-generation node B (NR gNB) 1c-10 and a new radio core network (NR CN) or a next-generation core network (NR CN) 1c-05. A new radio user equipment (NR UE) or terminal 1c-15 may access an external network via the NR gNB 1c-10 and the NR CN 1c-05.

[0105] exist Figure 1C In the present invention, NR gNB 1c-10 may correspond to the eNB of the existing LTE system. NR gNB 1c-10 is connected to NR UE 1c-15 through a radio channel and may provide better services compared to the existing NB. Because all user service data are served through shared channels in the next generation wireless communication system, an entity is required for collating the UE's buffer status information, available transmit power status information, channel status information, etc. and performing scheduling, and such operations may be performed by NR gNB 1c-10. A single NR gNB 1c-10 may control multiple cells. In the next generation wireless communication system, a bandwidth greater than the maximum bandwidth of LTE may be given to achieve the current ultra-high data rate, and beamforming technology and OFDM may additionally be used together as radio access technology.

[0106] The next generation wireless communication system can also use AMC to determine the modulation scheme and channel coding rate according to the channel state of the NR UE 1a-15. NR CN 1c-05 can perform functions such as mobility support, bearer setting, and quality of service (QoS) setting. NR CN 1c-05 is an entity for performing mobility management functions and various control functions for UE 1c-15, and can be connected to multiple NR gNB 1c-10. The next generation wireless communication system can cooperate with the existing LTE system, and the NR CN 1c-05 can be connected to the MME 1c-25 through a network interface. The MME 1c-25 can be connected to the existing eNB 1c-30.

[0107] Figure 1D and Figure 1E A schematic diagram showing the structure of a next generation wireless communication system according to an embodiment of the present disclosure.

[0108] refer to Figure 1D and Figure 1E , shows an example of configuring New Radio Dual Connectivity (NR-DC). Figure 1D and Figure 1EAs shown, the RAN of the next generation wireless communication system may include gNB 1d-10 and 1d-30 and 1e-10 and 1e-30, and access and mobility management functions (AMF) 1d-05 and 1d-25 and 1e-05 (new radio core network). New radio user equipment (NR UE) or terminal 1d-15 or 1e-15 can access the external network through gNB 1d-10 or 1e-10 and AMF 1d-05 or 1e-05.

[0109] refer to Figures 1C to 1E , the situation where macro cells and pico cells coexist can be considered. A macro cell is a cell controlled by a macro base station, and can provide services in a wider area (coverage area). On the other hand, a pico cell is a cell controlled by a secondary base station (secondary eNB (SeNB) or secondary gNB (SgNB)), and provides services in a very small area compared to a general macro cell. There is no strict criterion for distinguishing between macro cells and pico cells, but for example, the radius of the area of ​​a macro cell may be about 500 meters, and the radius of the area of ​​a pico cell may be about tens of meters. According to an embodiment of the present disclosure, a cell may include a pico cell and a macro cell. In this case, the macro cell may be an LTE base station (master eNB (MeNB)) or an NR base station (master gNB (MgNB)), and the pico cell may be an NR base station (SgNB) or an LTE base station (SeNB). In particular, a 5G base station supporting a pico cell can use a frequency band equal to or greater than 6 GHz.

[0110] In an embodiment of the present disclosure, the situation of coexistence of macro cells can be considered. A macro cell is a cell controlled by a macro base station and can provide services in a wider area. In this case, the macro cell may include an LTE base station (MeNB) and an LTE base station (SeNB). According to another embodiment of the present disclosure, the macro cell may include an LTE base station (MeNB) and an NR base station (SgNB). According to another embodiment of the present disclosure, the macro cell may include an NR base station (MgNB) and an LTE base station (SeNB). According to another embodiment of the present disclosure, the macro cell may include an NR base station (MgNB) and an NR base station (SgNB).

[0111] Figure 1F A schematic diagram showing a radio protocol architecture of a next generation wireless communication system according to an embodiment of the present disclosure.

[0112] refer to Figure 1F The radio protocol architecture of the next-generation wireless communication system includes NR service data adaptation protocol (SDAP) layers 1f-01 and 1f-45, NR PDCP layers 1f-05 and 1f-40, NR RLC layers 1f-10 and 1f-35, and NR MAC layers 1f-15 and 1f-30 for UE and NR gNB, respectively.

[0113] The main functions of NR SDAP layers 1f-01 and 1f-45 may include some of the following functions.

[0114] -Transmission of user plane data

[0115] - Mapping between QoS flows and Data Radio Bearers (DRBs) for both DL and UL

[0116] -Mark QoS flow ID in DL and UL packets

[0117] - Reflective QoS flow to DRB mapping for UL SDAP PDU

[0118] For the SDAP layer, for each PDCP layer, bearer or logical channel, the UE can receive settings about whether to use the header of the SDAP layer or the function of the SDAP layer through an RRC message. When setting the SDAP header, the UE can instruct the non-access layer (NAS) of the SDAP header to reflect the QoS 1-bit indicator and the access layer (AS) to reflect the QoS 1-bit indicator to update or reset the mapping information about the data bearer and QoS flow of UL and DL. The SDAP header may include a QoS flow ID indicating the QoS. The QoS information can be used as data processing priority information, scheduling information, etc. for supporting smooth services.

[0119] The main functions of NR PDCP layer 1f-05 or 1f-40 may include some of the following functions.

[0120] -Header compression and decompression: ROHC only

[0121] -Transmission of user data

[0122] - Deliver upper layer PDUs in sequence

[0123] - Out-of-order delivery of upper layer PDUs

[0124] - Reordering of received PDCP PDUs

[0125] - Duplicate detection of lower layer SDU

[0126] -Retransmitted PDCP SDU

[0127] -Encryption and decryption

[0128] - Timer-based SDU discard in uplink

[0129] The reordering function of the NR PDCP layer 1f-05 or 1f-40 (for reordering of received PDCP PDUs) may include a function of indicating that the PDCP PDUs received from the lower layer are to be reordered based on the PDCP sequence number (SN). The reordering function of the NR PDCP layer 1f-05 or 1f-40 (for reordering of received PDCP PDUs) may include a function of delivering the reordered data to the upper layer in sequence, a function of delivering the reordered data immediately without considering the sequence, a function of recording missing PDCP PDUs by reordering the PDCP PDUs, a function of reporting status information of the missing PDCP PDUs to the transmitter, and a function of requesting retransmission of the missing PDCP PDUs.

[0130] The main functions of the NR RLC layer 1f-10 or 1f-35 may include at least some of the following functions.

[0131] -Transmission of upper layer PDU

[0132] - Deliver upper layer PDUs in sequence

[0133] - Out-of-order delivery of upper layer PDUs

[0134] - Error correction via ARQ

[0135] - Concatenate, segment and reassemble RLC SDUs

[0136] - Re-segmentation of RLC data PDUs

[0137] - Reorder RLC data PDUs

[0138] - Duplicate detection

[0139] -Protocol error detection

[0140] -RLC SDU discarded

[0141] -RLC re-establishment

[0142] The in-sequence delivery function of the NR RLC layer 1f-10 or 1f-35 may represent a function of delivering the RLC SDU received from the lower layer to the upper layer in sequence. The in-sequence delivery function of the NR RLC layer 1f-10 or 1f-35 may include a function of reassembling the segmented RLC SDUs and delivering the RLC SDUs when receiving multiple RLC SDUs segmented from the RLC SDU, a function of reordering the received RLC PDUs based on the RLC SN or PDCPSN, a function of recording the missing RLC PDUs by reordering the RLC PDUs, a function of reporting the status information of the missing RLC PDUs to the transmitter, a function of requesting retransmission of the missing RLC PDUs, a function of delivering only the RLC SDUs before the missing RLC SDUs to the upper layer in sequence when there are missing RLC SDUs, a function of delivering all RLC SDUs received before the timer starts in sequence to the upper layer when a timer expires despite the presence of missing RLC SDUs, and a function of delivering all RLC SDUs received before the current time in sequence to the upper layer when a timer expires despite the presence of missing RLC SDUs. In addition, the NR RLC layer 1f-10 or 1f-35 may process the RLC PDU in the order of reception (in the order of arrival regardless of the sequence number) and deliver the RLC PDU to the PDCP entity out of order (out-of-order delivery), and reassemble the segments received or stored in the buffer into a complete RLC PDU, and process the RLC PDU and deliver it to the PDCP layer. The NR RLC layer 1f-10 or 1f-35 may not have a cascading function, and the cascading function may be performed by the NR MAC layer 1d-15 or 1d-30 or be replaced by a multiplexing function of the NR MAC layer 1f-15 or 1f-30.

[0143] The out-of-order delivery of the NR RLC layer 1f-10 or 1f-35 may refer to a function of delivering the RLC SDU received from the lower layer to the upper layer immediately out of sequence. The out-of-order delivery function of the NR RLC layer 1f-10 or 1f-35 may include a function of reassembling the segmented RLC SDU and delivering the RLC SDU when multiple RLC SDUs segmented from the RLC SDU are received, and a function of storing the RLC SN or PDCP SN of the received RLC PDU and recording the missing RLC PDU by sorting the RLC PDU.

[0144] The NR MAC layer 1f-15 or 1f-30 can be connected to multiple NR RLC layers 1f-10 or 1f-35 configured for a single UE, and the main functions of the NR MAC layer 1f-15 or 1f-30 may include at least some of the following functions.

[0145] - Mapping between logical channels and transport channels

[0146] -Multiplexing / demultiplexing MAC SDU

[0147] -Dispatch information report

[0148] - Error correction via HARQ

[0149] - Priority handling between logical channels of a UE

[0150] - Prioritize UEs through dynamic scheduling

[0151] -MBMS service identification

[0152] -Transmission format selection

[0153] -filling

[0154] The NR PHY layer 1f-20 or 1f-25 can channel-code and modulate the upper layer data into OFDM symbols and send the OFDM symbols through the radio channel, or demodulate the OFDM symbols received through the radio channel and channel-decode the OFDM symbols and deliver them to the upper layer.

[0155] Figure 1G A schematic diagram showing RRC modes of a UE belonging to a next generation wireless communication system and conversion relationships between modes according to an embodiment of the present disclosure is shown. The features of each RRC mode of the UE are as follows.

[0156] RRC_IDLE:

[0157] The UE may perform a discontinuous reception (DRX) operation according to a configuration related to a DRX operation configured by an upper layer.

[0158] The UE may perform inter-cell mobility based on the base station configuration.

[0159] The UE can monitor the short message service (SMS) by using the P-RNTI sent from the downlink control information (DCI). In addition, the UE can monitor the paging channel for the core network-based paging signal by using the 5G-S temporary mobile subscription identifier (5G-S-temporary mobilesubscription identifier, 5G-S-TMSI). In addition, the UE can perform measurements or reselection procedures on neighboring cells. In addition, the UE can receive system information or, when supported, request the base station to send system information.

[0160] RRC_INACTIVE:

[0161] The UE may perform DRX operation according to the configuration related to DRX operation configured by the upper layer or the RRC layer.

[0162] The UE may perform inter-cell mobility based on the base station configuration.

[0163] The UE may store the UE inactive AS context.

[0164] The UE may be configured via the RRC layer for the RAN-based notification area.

[0165] The UE can send or receive unicast data.

[0166] The UE can monitor SMS by using the P-RNTI sent from the DCI according to the configuration. In addition, the UE can monitor the paging channel for the core network-based paging signal by using the 5G-S-TMSI, and can monitor the paging channel for the RAN-based paging signal using the full-RNTI. In addition, the UE can perform a measurement or reselection procedure on a neighboring cell. In addition, the UE can perform a RAN-based notification area update procedure periodically or when outside the RAN-based notification area. In addition, the UE can receive system information or, when supported, request the base station to send system information.

[0167] RRC_CONNECTED:

[0168] The UE may store the AS context.

[0169] The UE can send or receive unicast data.

[0170] The UE can operate at the lower layer according to the DRX set by the base station.

[0171] A UE supporting CA can use at least one Scell ​​or SpCell simultaneously.

[0172] A UE supporting DC can use at least one SCG or MCG simultaneously.

[0173] The UE may perform inter-cell mobility in NR or between NR-LTE according to the indication of the base station. Alternatively, the UE may perform inter-cell mobility in NR or between NR-LTE according to the determination of the UE based on the base station configuration.

[0174] The UE may monitor the SMS by using the P-RNTI transmitted from the DCI. The UE may monitor the control channel to determine whether there is scheduling data. The UE may perform channel measurement and send the measurement result to the base station. In addition, the UE may perform measurement or reselection procedures on neighboring cells. In addition, the UE may receive system information.

[0175] Figure 1H A schematic diagram for describing a process in which a UE establishes a connection with a network by transitioning from an RRC idle mode to an RRC connected mode according to an embodiment of the present disclosure is shown.

[0176] refer to Figure 1H , when a UE that sends or receives data in RRC connected mode does not send or receive data for a certain reason or within a certain period of time, the gNB may send an RRCConnectionRelease message to the UE to transition to RRC idle mode (operation 1h-01). Thereafter, when data to be sent is generated, a UE that currently has no connection established (hereinafter referred to as an idle mode UE) may perform an RRC connection establishment procedure with the gNB. The UE may establish reverse transmission synchronization with the eNB through a random access procedure and send an RRCConnectionRequest message to the gNB (operation 1h-05). The RRCConnectionRequest message may include an identifier of the UE, an establishment cause, etc.

[0177] The gNB may send an RRCConnectionSetup message so that the UE establishes an RRC connection (operations 1h-10). The RRCConnectionSetup message may include configuration information for each service / bearer / RLC layer or for each logical channel or bearer, and may include information about whether to use ROHC for each bearer / logical channel, ROHC configuration information (e.g., ROHC version or initial information), statusReportRequired information (information for instructing the UE to perform PDCP status reporting by the gNB), and drb-ContinueROHC information (configuration information for maintaining and unchanged using the ROHC configuration information and included and sent in the PDCP layer configuration information (pdcp-config)). In addition, the RRCConnectionSetup message may include RRC connection configuration information, etc. The bearer used for the RRC connection is also called a signaling radio bearer (SRB) and may be used during the transmission and reception of RRC messages which are control messages between the UE and the gNB.

[0178] The UE that establishes the RRC connection may send an RRCConnectionSetupComplete message to the gNB (operation 1h-15). The RRCConnectionSetupComplete message may include a control message such as a SERVICE REQUEST message for requesting the MME to configure a bearer for a certain service for the UE. The gNB may send a SERVICE REQUEST message included in the RRCConnectionSetupComplete message to the MME (operation 1h-20), and the MME may determine whether to provide the service requested by the UE. As a result of the determination, when the service requested by the UE is to be provided, the MME may send an INITIAL CONTEXT SETUP REQUEST message to the gNB (operation 1h-25). The INITIAL CONTEXT SETUP REQUEST message may include QoS information to be applied when configuring the DRB, security information to be applied to the DRB (e.g., security keys, security algorithms, etc.), etc. The gNB may exchange SecurityModeCommand messages (operation 1h-30) and SecurityModeComplete messages (operation 1h-35) with the UE to configure the security mode. After configuring the security mode, the gNB may send an RRCConnectionReconfiguration message (operation 1h-40) to the UE.

[0179] The RRCConnectionReconfiguration message may include configuration information for each service / bearer / RLC layer or for each logical channel or bearer, and may include information on whether to use ROHC for each bearer / logical channel, ROHC configuration information (e.g., ROHC version or initial information), statusReportRequired information (information for instructing the UE to perform PDCP status reporting by the gNB), and drb-ContinueROHC information (configuration information for maintaining and unchanged using the ROHC configuration information and included and transmitted in the PDCP layer configuration information (pdcp-config)). In addition, the RRCConnectionReconfiguration message may include RRC connection configuration information, etc. The bearer for the RRC connection is also called SRB and can be used during transmission and reception of an RRC message which is a control message between the UE and the gNB.

[0180] In addition, the RRCConnectionReconfiguration message may include configuration information about the DRB to process user data, and the UE may configure the DRB by using the configuration information and send an RRCConnectionReconfigurationComplete message to the gNB (operation 1h-45). After completing the DRB configuration with the UE, the gNB sends an INITIAL CONTEXT SETUP COMPLETE message to the MME (operation 1h-50), and upon reception, the MME may exchange an S1 BEARER SETUP message and an S1 BEARER SETUP Response message with the S-GW to configure the S1 bearer (operations 1h-55 and 1h-60). The S1 bearer is a connection configured between the S-GW and the gNB for data transmission, and may correspond to the DRB in a one-to-one manner. After completing the above process, the UE may send data to or receive data from the gNB through the S-GW in operations 1g-65 and 1g-70. In this way, the general data transmission process can mainly include three steps: RRC connection establishment, security setup and DRB configuration. In addition, the gNB can send an RRCConnectionReconfiguration message to the UE to update, add or change the configuration for a certain reason (1h-75). The following [Table 1] is an example of PDCP configuration information included in the RRC connection reconfiguration message.

[0181]

Table 1

[0182]

[0183] The RRC connection reconfiguration message may include configuration information for each service / bearer / RLC layer or for each logical channel or bearer, and may include information on whether to use ROHC for each bearer / logical channel, ROHC configuration information, statusReportRequired information, and drb-ContinueROHC information. According to an embodiment of the present disclosure, the ROHC configuration information may include, for example, at least one of the ROHC version or initial information. According to an embodiment of the present disclosure, the statusReportRequired information may indicate information indicating that the PDCP status is reported to the UE from the base station. According to an embodiment of the present disclosure, the drb-ContinueROHC information is configuration information indicating that the ROHC configuration is maintained and unchanged, and may be sent by being included in the PDCP layer configuration information (pdcp-config). Among the multiple pieces of information included in the RRC connection reconfiguration message, UL-DataSplitThreshold may set a reference value for determining a method of dividing and sending one piece of data or a method of copying the same data and sending the copied data through different paths for a method of sending uplink (UL) data. In addition, the RRC connection reconfiguration message may include RRC connection configuration information, etc. A bearer for an RRC connection is also called an SRB and may be used during transmission and reception of an RRC message which is a control message between a UE and a base station.

[0184] In the present disclosure, a bearer may refer to an SRB and a DRB, wherein an SRB stands for a signaling radio bearer and a DRB stands for a data radio bearer. An SRB may be used to transmit and receive an RRC message of an RRC layer, and a DRB may be mainly used to transmit and receive user layer data. In addition, a UM DRB may refer to a DRB of an RLC layer operating in an unacknowledged mode (UM), and an AM DRB may refer to a DRB of an RLC layer operating in an acknowledged mode (AM).

[0185] Fig. 1I A schematic diagram for describing the ROHC protocol according to an embodiment of the present disclosure is shown.

[0186] Fig. 1IThe IP header 1f-05 and header 1f-10 indicate that the header overhead of the IP packet can be reduced when the ROHC protocol is applied. For example, when the IPv6 header is used, the IP header 1f-05 of 60 bytes can be compressed into a header 1f-10 of 2 bytes or 4 bytes. The header compression method of the ROHC protocol may not be a method using compression coding or source coding. In other words, the header compression method of the ROHC protocol may be as follows. First, the entire header information of the IP header (source IP address, destination IP address, TCP / IP sequence number, etc.) and the configuration information of the ROHC protocol (context identifier (CID) etc.) can be shared by the sending PDCP layer and the receiving PDCP layer. The entire header information of the IP header and the configuration information of the ROHC protocol can be sent by being included in the initialization and refresh status (IR) packet, the sending PDCP layer can piggyback the entire header information and the configuration information about the PDCP data PDU to the receiving PDCP layer, and the receiving PDCP layer can receive and share the entire header information and the configuration information. Most of the shared information is fixed information (source IP address, destination IP address, etc.), which will not change until the connection is re-established, and only a part of it can be dynamic information (CID, TCP / IP sequence number, etc.). Therefore, once the sending PDCP layer and the receiving PDCP layer share the entire header information and configuration information of the ROHC protocol, the sending PDCP layer only sends dynamic information to the receiving PDCP layer. In this way, when the sending PDCP layer only sends dynamic information instead of the entire header information of the IP header, the header overhead can be sent after being reduced and compressed. Therefore, the ROHC protocol only operates normally when the receiving PDCP layer normally receives the IR packet. Therefore, the sending end can send IR packets multiple times.

[0187] The header compression protocol (ROHC protocol) can be applied to the PDCP layer, and when the entire header information and the configuration information of the ROHC protocol are not shared and synchronized between the sending PDCP layer and the receiving PDCP layer, the ROHC protocol will not be able to be used normally (1i-15, 1i-20). In other words, when the sending PDCP layer and the receiving PDCP layer do not share and synchronize the entire header information and configuration information, even when the sending PDCP layer compresses and sends the IP header, the receiving PDCP layer cannot decompress the compressed IP header (1i-15, 1i-20).

[0188] Therefore, the transmitting PDCP layer first transmits the IR packet 1i-25 including the entire header information and the configuration information to the receiving PDCP layer, and after receiving the IR packet 1i-25, the receiving PDCP layer synchronizes the entire header information and the configuration information with those of the transmitting PDCP layer (1i-15, 1i-35). The transmitting PDCP layer may compress and transmit the header by applying the ROHC protocol to the IP packet after synchronization (1i-30), and the receiving PDCP layer may decompress the ROHC header for the received IP packet.

[0189] Figure 1J A schematic diagram for describing the data processing process of the sending PDCP layer and the receiving PDCP layer according to an embodiment of the present disclosure is shown.

[0190] After receiving the IP packet (1j-05), the transmitting PDCP layer performs header compression (1j-10) on the IP header when the transmitting PDCP layer uses the ROHC protocol, and performs integrity protection (1j-15) on the control plane data or SRB. In addition, the transmitting PDCP layer can encode the data on which header compression and integrity protection are performed by using a security key and a count value (1j-20). In addition, the transmitting PDCP layer can allocate a PDCP SN for the encoded data, configure a header field corresponding to the data (control plane data or user plane data), attach a header to the encoded data, and send the header to the lower layer.

[0191] After receiving the PDCP PDU from the lower layer, the receiving PDCP layer can read the PDCP SN and header fields of the PDCP header and remove the PDCP header (1j-30). The receiving PDCP layer can decode the data from which the header is removed by using a security key and a count value (1j-35). In addition, the receiving PDCP layer can perform integrity verification on the control plane data or SRB (1j-40). In addition, when the header is compressed by the PDCP protocol, the receiving PDCP layer can decompress the header and reconstruct the original IP header (1j-45). In addition, the receiving PDCP layer can send the reconstructed IP packet to the upper layer (1j-50).

[0192] Throughout the present disclosure, the term "sequential" may mean ascending order. In the present disclosure, header decompression may include a process in which the ROHC protocol verifies a header of a TCP / IP packet or an upper layer packet, and when the packet is an IR packet, header decompression may include an operation of verifying information of the IR packet and updating configuration information of the ROHC protocol based on the verified information, and when the header is compressed, header decompression may include an operation of verifying configuration information of the ROHC protocol and reconstructing a decompressed header.

[0193] According to the downlink (DL) scenario and the UL scenario, the transmitting PDCP layer and the receiving PDCP layer described in the present disclosure may be entities in which each PDCP layer belongs to a UE or a base station. In other words, in the UL scenario, the transmitting PDCP layer may represent an entity of the UE, and the receiving PDCP layer may represent an entity of the base station. In addition, in the DL scenario, the transmitting PDCP layer may represent an entity of the base station, and the receiving PDCP layer may represent an entity of the UE. The re-establishment process of the transmitting PDCP layer and the receiving PDCP layer described in the present disclosure may be applied to these two scenarios, and the operation of the transmitting PDCP layer and the operation of the receiving PDCP layer may also be applied to these two scenarios.

[0194] Figure 1K A schematic diagram for describing a handover process in a next generation wireless communication system according to an embodiment of the present disclosure is shown.

[0195] When a periodic or specific event is met, the UE 1k-01 in the connected mode state sends cell measurement information (measurement report) to the current source gNB 1k-02 (1k-05). The source gNB 1k-02 can determine whether the UE 1k-01 is to perform a handover to a neighboring cell based on the cell measurement information. Handover is a technique for changing the source gNB 1k-02 that provides service to the UE 1k-01 in the connected mode state to another gNB (or another cell in the same gNB).

[0196] When the source gNB 1k-02 determines the handover, the source gNB 1k-02 requests the new gNB (i.e., the target gNB 1k-03) to provide services to the UE 1k-01 for the handover by sending a handover (HO) request message (1k-10). When the target gNB 1k-03 accepts the HO request, the target gNB 1k-03 sends a HO request confirm message to the source gNB 1k-02 (1k-15). After receiving the HO request confirm message, the source gNB 1k-02 sends a HO command message to the UE 1k-01 (1k-20). The HO command message is sent from the source gNB 1k-02 to the UE 1k-01 by using an RRC connection reconfiguration message (1k-20). After receiving the HO command message, the UE 1k-01 stops exchanging data with the source gNB 1k-02 and starts the T304 timer. When the handover of UE 1k-01 to the target gNB 1k-03 is not successful within a certain period of time, the T304 timer sets the UE 1k-01 to the original setting and sets it to the RRC idle state. When there is DL data, the source gNB 1k-02 sends the SN status for UL / DL data and sends the DL data to the target gNB 1k-03 (1k-30 and 1k-35). UE 1k-01 attempts random access to the target cell (1k-40) instructed by the source gNB 1k-02. UE 1k-01 attempts random access to notify the target cell that UE 1k-01 is moving through handover, and at the same time, synchronize UL. For random access, UE 1k-01 sends a preamble corresponding to the preamble ID provided from the source gNB 1k-02 or a randomly selected preamble ID to the target gNB 1k-03. When a certain number of subframes have passed after sending the preamble, UE 1k-01 monitors whether a random access response (RAR) message is sent from the target gNB 1k-03. The time period for monitoring whether the RAR message is sent is called the RAR window. Within a certain time, when the RAR message is received (1k-45), UE 1k-01 sends an RRCConnectionReconfigurationComplete message as a HO completion message to the target gNB 1k-03 (1k-55). After successfully receiving the RAR message from the target gNB 1k-03, UE 1k-01 stops the T304 timer (1k-50). The target gNB 1k-03 requests the MME (or S-GW or AMF) 1k-04 to change the path (1k-60 and 1k-65) in order to change the path of the bearer set in the source gNB 1k-02, and notifies the source gNB 1k-02 to release the UE context of UE 1k-01 (1k-70).Therefore, UE 1k-01 attempts to receive data from the target gNB 1k-03 from the time point when the RAR window starts, and after receiving the RAR message, starts sending data to the target gNB 1k-03 while sending the RRCConnectionReconfigurationComplete message.

[0197] Figure 1L A schematic diagram for describing a process of restoring a connection by a UE in an RRC inactive mode according to an embodiment of the present disclosure is shown.

[0198] The gNB may transition the UE to the RRC inactive mode by sending an RRCRelease message including an indicator (suspend-config) for transitioning to the RRC inactive mode to the UE (11-01). After receiving the RRCRelease message, the UE transitions to the RRC inactive mode, and then may perform an RRC connection recovery procedure when a connection with the network needs to be established for some reason (e.g., receiving a paging message, generating UL data, or updating a paging area).

[0199] During the RRC connection recovery process, the UE may perform a random access process and send a RRCResumeRequest message including a connection recovery identifier to the gNB via message 3 (11-05). The gNB may receive the RRCResumeRequest message and identify the connection recovery identifier of the UE. When the gNB is able to retrieve and confirm the context of the UE, the gNB may send a RRCResume message to the UE via message 4 to allow the connection to be restored (11-10). The RRCResume message may include new configuration information for each service / bearer / RLC layer or for each logical channel or bearer, and may include information about whether ROHC is used for each bearer / logical channel, ROHC configuration information (e.g., ROHC version or initial information), statusReportRequired information (information by which the gNB instructs the UE to perform a PDCP status report), and drb-ContinueROHC information (configuration information for maintaining and unchangedly using the ROHC configuration information and included and sent in the PDCP layer configuration information (pdcp-config)).

[0200] When there is new configuration information in the received RRCResume message, the UE can update the UE configuration by reflecting the new configuration information, or when there is no new configuration information in the RRCResume message, the UE can use the stored UE context. The UE that resumes the RRC connection can send a RRCResumeComplete message to the gNB (operation 1l-15). When the above process is completed, the UE and gNB can send and receive data (1l-65).

[0201] A first embodiment of the present disclosure of an operation of a UE in which header compression protocol configuration information of a PDCP layer for each bearer of the UE is effectively used is as follows.

[0202] -When the UE receives an RRCReconfiguration message from the gNB indicating a handover,

[0203] - or when the UE receives an RRCResume message while performing an RRC connection recovery procedure,

[0204] ■When an RRC is received, the received RRC message includes UE configuration information, the UE configuration information indicates that a part of the current UE configuration information but not the entire current UE configuration information (for example, not including the entire configuration change indicator (fullconfig)) has changed, and the received RRC message includes configuration information for adding or changing a data bearer, the UE can perform the following operations for each bearer identifier.

[0205] When the PDCP layer configuration (pdcp-config) is included for the bearer identifier,

[0206] ●The UE may reconfigure the current PDCP layer of the bearer identifier using the new PDCP layer configuration information received above.

[0207] ●When the PDCP layer configuration information includes the header compression protocol configuration information continuous use indicator (drb-ContinueROHC),

[0208] ▲The UE can indicate to the lower layer (PDCP layer) that the header compression protocol configuration information continuous use indicator (drb-ContinueROHC) is configured.

[0209] ◆When the UE is performing the PDCP layer re-establishment procedure and the header compression protocol configuration information continuous use indicator (drb-ContinueROHC) is indicated or configured,

[0210] ●The sending PDCP layer may not initialize the header compression protocol configuration information for UM DRB and AM DRB.

[0211] • The receiving PDCP layer may not perform a header decompression procedure on the stored PDCP layer data (eg, PDCP SDU) for the AM DRB.

[0212] ●The receiving PDCP layer may not initialize the header decompression protocol configuration information for UM DRB and AM DRB.

[0213] ◆When the UE performs the PDCP layer re-establishment procedure without indicating or configuring the header compression protocol configuration information continuous use indicator (drb-ContinueROHC),

[0214] ●The sending PDCP layer can initialize the header compression protocol configuration information for UM DRB and AM DRB.

[0215] ● The receiving PDCP layer may perform a header decompression process on stored PDCP layer data (e.g., PDCP SDU) for the AM DRB based on the current header decompression protocol configuration information. (When the header decompression protocol configuration information is initialized, the stored data that was decompressed only with the previous header decompression protocol cannot be decompressed later. Therefore, before the header decompression protocol configuration information is initialized, the stored data may need to be decompressed with the current header decompression protocol.)

[0216] ●The receiving PDCP layer may initialize header decompression protocol configuration information for UM DRB and AM DRB.

[0217] -When the UE receives the RRCResume message while performing the RRC connection recovery procedure,

[0218] ■When an RRC message is received, the received RRC message includes UE configuration information, and the UE configuration information indicates that part of the current UE configuration information but not the entire current UE configuration information (for example, not including the entire configuration change indicator (fullconfig)) has changed, the UE can perform the following operations for each bearer identifier.

[0219] ◆The UE may reconstruct the primary cell group information (PHY layer, MAC layer or RLC layer configuration information) and the PDCP layer configuration information (pdcp-config) from the stored UE context. When the PDCP layer configuration information is reconstructed, the header compression protocol configuration information continuous use indicator (drb-ContinueROHC) may not be reconstructed. This is because the header compression protocol configuration information continuous use indicator (drb-ContinueROHC) is a one-time indicator that is applied each time it is re-received, and the stored value is not used.

[0220] A second embodiment of the present disclosure of an operation of a UE in which header compression protocol configuration information of a PDCP layer for each bearer of the UE is effectively used is as follows.

[0221] -When the UE receives an RRCReconfiguration message from the gNB indicating a handover,

[0222] - or when the UE receives an RRCResume message while performing an RRC connection recovery procedure,

[0223] ■When an RRC is received, the received RRC message includes UE configuration information, the UE configuration information indicates that a part of the current UE configuration information but not the entire current UE configuration information (for example, not including the entire configuration change indicator (fullconfig)) has changed, and the received RRC message includes configuration information for adding or modifying a data bearer, the UE can perform the following operations for each bearer identifier.

[0224] When the PDCP layer reestablishment procedure indication (reestablishPDCP) is included or configured (set) for the bearer identifier,

[0225] When the PDCP layer configuration information is included and the header compression protocol configuration information continuous use indicator (drb-ContinueROHC) is included in the PDCP layer configuration information,

[0226] ■The UE can indicate to the lower layer (PDCP layer) that the header compression protocol configuration information continuous use indicator (drb-ContinueROHC) is configured.

[0227] • The UE may perform a PDCP layer re-establishment procedure for the bearer identifier.

[0228] ● In addition, when the UE is instructed or configured to indicate or configure the header compression protocol configuration information continuous use indicator (drb-ContinueROHC) while performing the PDCP layer re-establishment procedure,

[0229] ■For UM DRB and AM DRB, the sending PDCP layer may not initialize the header compression protocol configuration information.

[0230] ■ For AM DRBs, the receiving PDCP layer may not perform a header decompression procedure on the stored PDCP layer data (eg, PDCP SDU).

[0231] ■For UM DRB and AM DRB, the receiving PDCP layer may not initialize the header decompression protocol configuration information.

[0232] ●When the UE performs the PDCP layer re-establishment procedure while there is no indication or no configuration of the header compression protocol configuration information continuous use indicator (drb-ContinueROHC),

[0233] ■For UM DRB and AM DRB, the sending PDCP layer can initialize the header compression protocol configuration information.

[0234] ■For AM DRBs, the receiving PDCP layer may perform a header decompression process on stored PDCP layer data (e.g., PDCP SDUs) based on the current header decompression protocol configuration information. (When the header decompression protocol configuration information is initialized, the stored data that was decompressed only with the previous header decompression protocol cannot be decompressed later. Therefore, before the header decompression protocol configuration information is initialized, the stored data may need to be decompressed with the current header decompression protocol.)

[0235] ■For UM DRB and AM DRB, the receiving PDCP layer can initialize the header decompression protocol configuration information.

[0236] When the PDCP layer configuration (pdcp-config) is included for the bearer identifier,

[0237] ●The UE may reconfigure the current PDCP layer of the bearer identifier using the new PDCP layer configuration information received above.

[0238] -When the UE receives the RRCResume message while performing the RRC connection recovery procedure,

[0239] ■When an RRC message is received, the received RRC message includes UE configuration information, and the UE configuration information indicates that part of the current UE configuration information but not the entire current UE configuration information (for example, not including the entire configuration change indicator (fullconfig)) has changed, the UE can perform the following operations for each bearer identifier.

[0240] ◆The UE can reconstruct the primary cell group information (PHY layer, MAC layer or RLC layer configuration information) and the PDCP layer configuration information (pdcp-config) from the stored UE context. When the PDCP layer configuration information is reconstructed, the header compression protocol configuration information continuous use indicator (drb-ContinueROHC) cannot be reconstructed. This is because the header compression protocol configuration information continuous use indicator (drb-ContinueROHC) is a one-time indicator that is applied every time it is re-received, and the stored value is not used.

[0241] A third embodiment of the present disclosure of an operation of a UE in which header compression protocol configuration information of a PDCP layer for each bearer of the UE is effectively used is as follows.

[0242] Operation of UE and apparatus related to UE PDCP configuration and PDCP operation

[0243] 1. Receive RRC setup message from base station

[0244] 2 Receive the RRC setup message from the base station and configure the PDCP device of the first radio bearer (SRB1)

[0245] 3. Receive the RRCReconfiguration message from the base station and configure the PDCP device of the second radio bearer (SRB2) and the PDCP device of the third radio bearer (DRB)

[0246] 4. Send and receive PDCP PDUs including RRC control messages through the first radio bearer and the second radio bearer, and send and receive PDCP PDUs including IP packets to and from the base station through the third radio bearer

[0247] 5. Apply the first operation (encryption / decryption) to the first radio bearer and the second radio bearer, and apply the first operation and the second operation (header compression) to the third radio bearer.

[0248] 6. Receive the RRCReconfiguration message including ReconfigurationWithSync from the base station

[0249] 7. Apply the third operation (SDU discard, PDCP variable initialization) to the first radio bearer and the second radio bearer, and apply the fourth operation (PDCP re-establishment) and the optional fifth operation (ROHC continuation) to the third radio bearer.

[0250] A. When the PDCP configuration information via the third radio bearer indicates a predetermined parameter (drb-ContinueROHC), the fifth operation is performed. When there is no indication, the fifth operation is not performed.

[0251] 8 Receive RRCRelease message including SuspendConfig from base station

[0252] 9. Store the following information in the UE context

[0253] A. The entire PDCP configuration information of the first radio bearer or at least a portion of the PDCP configuration information of the first radio bearer

[0254] B. The entire PDCP configuration information of the second radio bearer or at least a portion of the PDCP configuration information of the second radio bearer

[0255] C. Store the first parameter set (PDCP-SN-Size, header compression configuration information, discardTimer, integrityProtection) in the PDCP configuration information of the third radio bearer, and discard the second parameter set (drb-continueROHC) (or store both the first parameter set and the second parameter set, and apply only the first parameter set to operation 12)

[0256] 10. Performing INACTIVE state operations

[0257] 11. Send a RRCResumeRequest message to the base station. Reconstruct the PDCP configuration of the first radio bearer and resume the operation of the first radio bearer

[0258] 12. Receive an RRCResume message from the base station. Reconstruct the PDCP configuration of the second radio bearer and resume the operation of the second radio bearer. Reconstruct the PDCP configuration by applying the remaining configuration information of the PDCP configuration of the third radio bearer except the second parameter set. Resume the operation of the third radio bearer.

[0259] A. Only configure the first radio bearer or the second radio bearer

[0260] B. Multiple third radio bearers are configurable

[0261] C. The PDCP configuration information for the first radio bearer and the second radio bearer is the third parameter set (UL-DataSplitThreshold)

[0262] D. The PDCP configuration information for the third radio bearer is the first parameter set and the second parameter set

[0263] E. The first parameter set is a parameter set that is valid in both the first event and the second event.

[0264] F The second parameter set is a parameter set that is valid in the first event and invalid in the second event.

[0265] G. The first event is the event of receiving an RRC control message including a predetermined parameter set

[0266] The second event is an event of receiving a predetermined RRC control message not including a parameter by which the UE stores a predetermined parameter obtained through a previously received RRC control message.

[0267] Figure 1MA schematic diagram showing the operation of a UE according to an embodiment of the present disclosure.

[0268] The UE may receive an RRC message from a base station during handover or RRC connection recovery (1m-05). The UE may identify whether PDCP layer configuration information for each bearer is included in the received RRC message (1m-10), and when there is PDCP layer configuration information for the bearer, the UE may identify whether a header compression protocol configuration information continuous use indicator is included in the PDCP layer configuration information (1m-15). It may be identified through the RRC message which of SRB1, SRB2, and DRB is configured for each bearer. The RRC message may be at least one of an RRCConnectionReconfiguration message, an RRC setup message, or an RRCResumeRequest message.

[0269] When the header compression protocol configuration information continuous use indicator is included in the PDCP layer configuration information (1m-15) or according to another embodiment of the present disclosure, when the header compression protocol configuration information continuous use indicator is set to 1 in the PDCP layer configuration information, the UE does not initialize the header compression protocol configuration information when reestablishing the PDCP layer corresponding to the bearer (1m-20). The identification of the header compression protocol configuration information continuous use indicator can reflect the type of the bearer identified by the RRC message.

[0270] When the header compression protocol configuration information continuous use indicator is not included in the PDCP layer configuration information (1m-15) or according to another embodiment of the present disclosure, when the header compression protocol configuration information continuous use indicator is set to 0 in the PDCP layer configuration information, the UE initializes the header compression protocol configuration information when reestablishing the PDCP layer corresponding to the bearer (1m-25). The identification of the header compression protocol configuration information continuous use indicator can reflect the type of the bearer identified by the RRC message.

[0271] Figure 1N A schematic diagram showing the structure of a UE according to an embodiment of the present disclosure.

[0272] refer to Figure 1N , the UE includes a radio frequency (RF) processor 1n-10, a baseband processor 1n-20, a storage 1n-30, and a controller 1n-40. However, the UE is not limited thereto, and may include more Figure 1N More or fewer components than those shown.

[0273] The RF processor 1n-10 can perform functions for sending and receiving signals through a radio channel, such as signal band conversion and amplification. That is, the RF processor 1n-10 up-converts the baseband signal provided by the baseband processor 1n-20 into an RF band signal and transmits the RF band signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processor 1n-10 may include a transmitting filter, a receiving filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), and an analog-to-digital converter (ADC). Although Figure 1N Only a single antenna is shown in the figure, but the UE may include multiple antennas. The RF processor 1n-10 may include multiple RF chains. The RF processor 1n-10 can perform beamforming. For beamforming, the RF processor 1n-10 can adjust the phase and amplitude of signals sent or received through multiple antennas or antenna elements. The RF processor 1n-10 can perform multiple-input multiple-output (MIMO) and can receive multiple layers of data in MIMO operation. Under the control of the controller 1n-40, the RF processor 1n-10 can perform scanning of the receive beam by appropriately configuring multiple antennas or antenna elements, or adjust the direction and beam width of the receive beam to coordinate with the transmit beam.

[0274] The baseband processor 1n-20 can convert between baseband signals and bit streams based on the physical layer specifications of the system. For example, for data transmission, the baseband processor 1n-20 generates complex symbols by encoding and modulating the transmission bit stream. For data reception, the baseband processor 1n-20 can reconstruct the received bit stream by demodulating and decoding the baseband signal provided by the RF processor 1n-10. For example, according to the OFDM scheme, for data transmission, the baseband processor 1n-20 generates complex symbols by encoding and modulating the transmission bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols by performing inverse fast Fourier transform (IFFT) and cyclic prefix (CP) insertion. For data reception, the baseband processor 1n-20 can split the baseband signal provided by the RF processor 1n-10 into units of OFDM symbols, reconstruct the signal mapped to the subcarrier by performing a fast Fourier transform (FFT), and then reconstruct the received bit stream by demodulating and decoding the signal.

[0275] The baseband processor 1n-20 and the RF processor 1n-10 send and receive signals as described above. In this way, each of the baseband processor 1n-20 and the RF processor 1n-10 may also be referred to as a transmitter, a receiver, a transceiver, or a communicator. At least one of the baseband processor 1n-20 or the RF processor 1n-10 may include multiple communication modules to support a variety of different radio access technologies. In addition, at least one of the baseband processor 1n-20 or the RF processor 1n-10 may include multiple communication modules to process signals of different frequency bands. For example, different radio access technologies may include LTE networks, NR networks, and the like. Different frequency bands may include SHF (e.g., 2.5 GHz and 5 GHz) bands and mmWave (e.g., 60 GHz) bands. The UE may send or receive signals to or from a base station by using the baseband processor 1n-20 and the RF processor 1n-10, and the signal may include control information and data.

[0276] The storage 1n-30 may store data used for the operation of the UE, such as basic programs, application programs, and configuration information. The storage 1n-30 may provide the stored data according to the request of the controller 1n-40. The storage 1n-30 may be configured in a storage medium such as a ROM, RAM, hard disk, CD-ROM or DVD, or a combination thereof. In addition, the storage 1n-30 may be configured in a plurality of memories.

[0277] The controller 1n-40 may control the overall operation of the UE. For example, the controller 1n-40 may send and receive signals through the baseband processor 1n-20 and the RF processor 1n-10. The controller 1n-40 may record data on the storage 1n-30 and read data from the storage 1n-30. In this regard, the controller 1n-40 may include at least one processor. For example, the controller 1n-40 may include a communication processor (CP) for controlling communications and an application processor (AP) for controlling an upper layer such as an application. In addition, the controller 1n-40 may include a multi-connection processor 1n-42. In addition, at least one component in the UE may be embodied in one chip.

[0278] Fig.1O A schematic diagram showing the structure of an electronic device 10-01 for supporting traditional network communication and 5G network communication according to an embodiment of the present disclosure is shown.

[0279] refer to Fig.1O, the electronic device 1o-01 may include a first communication processor 1o-12, a second communication processor 1o-14, a first radio frequency integrated circuit (RFIC) 1o-22, a second RFIC 1o-24, a third RFIC 1o-26, a fourth RFIC 1o-28, a first radio frequency front end (RFFE) 1o-32, a second RFFE 1o-34, a first antenna module 1o-42, a second antenna module 1o-44 and an antenna 1o-48. The electronic device 1o-01 may also include a processor 1o-20 and a memory 1o-30. The network 1o-99 may include a first network 1o-92 and a second network 1o-94. According to another embodiment of the present disclosure, the electronic device 1o-01 may also include Fig.1O At least one component among those shown, and the network 1o-99 may also include at least one other network. According to an embodiment of the present disclosure, the first communication processor 1o-12, the second communication processor 1o-14, the first RFIC 1o-22, the second RFIC 1o-24, the fourth RFIC 1o-28, the first RFFE 1o-32 and the second RFFE 1o-34 may form at least a part of the wireless communication module 1o-10. According to another embodiment of the present disclosure, the fourth RFIC 1o-28 may be omitted or may be included as part of the third RFIC 1o-26.

[0280] The first communication processor 1o-12 may support the establishment of a communication channel for a frequency band to be used for wireless communication with the first network 1o-92, and may support traditional network communication through the established communication channel. According to various embodiments of the present disclosure, the first network 1o-92 may be a traditional network including a 2G, 3G, 4G or LTE network. The second communication processor 1o-14 may support the establishment of a communication channel corresponding to an allocated frequency band (e.g., about 6 GHz to about 60 GHz) among the frequency bands to be used for wireless communication with the second network 1o-94, and may support 5G network communication through the established communication channel. According to various embodiments of the present disclosure, the second network 1o-94 may be a 5G network defined by 3GPP. In addition, according to an embodiment of the present disclosure, the first communication processor 1o-12 or the second communication processor 1o-14 may support the establishment of another allocated frequency band (e.g., about 6 GHz or lower) among the frequency bands to be used for wireless communication with the second network 1o-94, and may support 5G network communication through the established communication channel. According to an embodiment of the present disclosure, the first communication processor 1o-12 and the second communication processor 1o-14 can be implemented in a single chip or a single package. According to various embodiments of the present disclosure, the first communication processor 1o-12 or the second communication processor 1o-14 can be implemented in a single chip or a single package with the processor 1o-20, the auxiliary processor or the communication module.

[0281] During transmission, the first RFIC 1o-22 may convert a baseband signal generated by the first communication processor 1o-12 into an RF signal of about 700 MHz to about 3 GHz for a first network 1o-92 (e.g., a legacy network). During reception, the RF signal may be obtained from the first network 1o-92 (e.g., a legacy network) via an antenna (e.g., a first antenna module 1o-42) and pre-processed by an RFFE (e.g., a first RFFE 1o-32). The first RFIC 1o-22 may convert the pre-processed RF signal into a baseband signal processed by the first communication processor 1o-12.

[0282] During transmission, the second RFIC 1o-24 can convert the baseband signal generated by the first communication processor 1o-12 or the second communication processor 1o-14 into an RF signal (hereinafter referred to as a 5G Sub6 RF signal) of the Sub6 frequency band (e.g., approximately 6 GHz or lower) for the second network 1o-94 (e.g., a 5G network). During reception, the 5G Sub6 RF signal can be obtained from the second network 1o-94 (e.g., a 5G network) through an antenna (e.g., a second antenna module 1o-44) and pre-processed by an RFFE (e.g., a second RFFE 1o-34). The second RFIC 1o-24 can convert the pre-processed 5G Sub6 RF signal into a baseband signal processed by a communication processor corresponding to the first communication processor 1o-12 or the second communication processor 1o-14.

[0283] During transmission, the third RFIC 1o-26 may convert a baseband signal generated by the second communication processor 1o-14 into an RF signal (hereinafter referred to as a 5G Above6 RF signal) of a 5G Above6 frequency band (e.g., approximately 6 GHz to approximately 60 GHz) to be used for a second network 1o-94 (e.g., a 5G network). During reception, the 5G Above6 RF signal may be obtained from the second network 1o-94 (e.g., a 5G network) via an antenna (e.g., antenna 1o-48) and pre-processed by the third RFFE 1o-36. The third RFIC 1o-26 may convert the pre-processed 5G Above6 RF signal into a baseband signal processed by the second communication processor 1o-14. According to an embodiment of the present disclosure, the third RFFE 1o-36 may be configured as part of the third RFIC 1o-26.

[0284] According to an embodiment of the present disclosure, the electronic device 1o-01 may include a fourth RFIC 1o-28 that is separate from the third RFIC 1o-26 or is part of the third RFIC 1o-26. In this case, the fourth RFIC 1o-28 may convert the baseband signal generated by the second communication processor 1o-14 into an RF signal (hereinafter referred to as an IF signal) of an intermediate frequency (IF) band (e.g., about 9 GHz to about 11 GHz), and send the IF signal to the third RFIC 1o-26. The third RFIC 1o-26 may convert the IF signal into a 5G Above 6 RF signal. During reception, the 5G Above 6 RF signal may be received from the second network 1o-94 (e.g., a 5G network) via an antenna (e.g., antenna 1o-48) and converted into an IF signal by the third RFIC 1o-26. The fourth RFIC 1o-28 may convert the IF signal into a baseband signal processed by the second communication processor 1o-14.

[0285] According to an embodiment of the present disclosure, the first RFIC 1o-22 and the second RFIC 1o-24 may be implemented as at least a portion of a single chip or a single package. According to an embodiment of the present disclosure, the first RFFE 1o-32 and the second RFFE 1o-34 may be implemented as at least a portion of a single chip or a single package. According to an embodiment of the present disclosure, at least one of the first antenna module 1o-42 or the second antenna module 1o-44 may be omitted or may be combined with another antenna module to process RF signals of multiple corresponding frequency bands.

[0286] According to an embodiment of the present disclosure, the third RFIC 1o-26 and the antenna 1o-48 may be arranged on the same substrate to configure the third antenna module 1o-46. For example, the wireless communication module 1o-10 or the processor 1o-20 may be arranged on a first substrate (e.g., a main printed circuit board (PCB)). In this case, the third RFIC 1o-26 may be arranged on a partial area (e.g., a bottom surface) of a second substrate (e.g., a sub-PCB) different from the first substrate, and the antenna 1o-48 may be arranged on another partial area (e.g., a top surface) of the second substrate to form a third antenna module 1o-46. According to an embodiment of the present disclosure, the antenna 1o-48 may include, for example, an antenna array for beamforming. By arranging the third RFIC 1o-26 and the antenna 1o-48 on the same substrate, the length of the transmission path between them can be reduced. Therefore, for example, the loss (e.g., attenuation) of signals in a high frequency band (e.g., about 6 GHz to about 60 GHz) for 5G network communication caused by the transmission path can be prevented. Therefore, the communication quality or speed between the electronic device 1o-01 and the second network 1o-94 (e.g., a 5G network) can be increased.

[0287] The second network 1o-94 (e.g., a 5G network) can operate independently (e.g., independent (SA)) of the first network 1o-92 (e.g., a traditional network) or connected to the first network 1o-92 (e.g., non-independent (NSA)). For example, the 5G network may only include an access network (e.g., a 5G radio access network (RAN) or a next generation RAN (NG RAN)) and does not include a core network (e.g., a next generation core (NGC)). In this case, the electronic device 1o-01 can access the access network of the 5G network and access an external network (e.g., the Internet) under the control of the core network of the traditional network (e.g., the evolved packet core (EPC)). Protocol information for communicating with the traditional network (e.g., LTE protocol information) and protocol information for communicating with the 5G network (e.g., new radio (NR) protocol information) can be stored in the memory 1o-30 and accessed by another component (e.g., the processor 1o-20, the first communication processor 1o-12, or the second communication processor 1o-14).

[0288] Figure 1P A block diagram showing the structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0289] refer to Figure 1P , the base station may include an RF processor 1p-10, a baseband processor 1p-20, a communicator 1p-30, a storage 1p-40, and a controller 1p-50. However, the base station is not limited thereto, and may include more Figure 1P More or fewer components than those shown.

[0290] The RF processor 1p-10 can perform functions for sending and receiving signals through a radio channel, such as signal band conversion and amplification. That is, the RF processor 1p-10 up-converts the baseband signal provided by the baseband processor 1p-20 into an RF band signal and transmits the RF band signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processor 1p-10 may include a transmitting filter, a receiving filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC. Although Figure 1P Only a single antenna is shown in the figure, but the RF processor 1p-10 may include multiple antennas. The RF processor 1p-10 may include multiple RF chains. In addition, the RF processor 1p-10 can perform beamforming. For beamforming, the RF processor 1p-10 can adjust the phase and amplitude of signals sent or received through multiple antennas or antenna elements. The RF processor 1p-10 can perform DL MIMO by sending data of two or more layers.

[0291] The baseband processor 1p-20 can convert between baseband signals and bit streams based on the physical layer specifications of the first radio access technology. For example, for data transmission, the baseband processor 1p-20 generates complex symbols by encoding and modulating the transmission bit stream. For data reception, the baseband processor 1p-20 reconstructs the received bit stream by demodulating and decoding the baseband signal provided from the RF processor 1p-10. For example, according to the OFDM scheme, for data transmission, the baseband processor 1p-20 generates complex symbols by encoding and modulating the transmission bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols by performing IFFT and CP insertion. For data reception, the baseband processor 1p-20 can split the baseband signal provided from the RF processor 1p-10 in units of OFDM symbols, reconstruct the signal mapped to the subcarrier by performing FFT, and then reconstruct the received bit stream by demodulating and decoding the signal. The baseband processor 1p-20 and the RF processor 1p-10 send and receive signals as described above. As such, each of the baseband processor 1p-20 and the RF processor 1p-10 may also be referred to as a transmitter, a receiver, a transceiver, a communicator, or a wireless communicator. The base station may send or receive a signal to or from the UE by using the baseband processor 1p-20 and the RF processor 1p-10, and the signal may include control information and data.

[0292] The communicator 1p-30 may provide an interface for communicating with other nodes in the network. According to some embodiments of the present disclosure, the communicator 1p-30 may be a backhaul communicator.

[0293] The storage 1p-40 can store data used for the operation of the base station as described above, for example, basic programs, applications, and configuration information. In particular, the storage 1p-40 can store information about the bearers allocated to the connected UEs, measurement reports sent from the connected UEs, and the like. The storage 1p-40 can store standard information for determining whether to provide multiple connections to the UE or to release multiple connections from the UE. The storage 1p-40 can provide stored data upon request of the controller 1p-50. The storage 1p-40 can be configured in a storage medium, such as a ROM, a RAM, a hard disk, a CD-ROM or a DVD, or a combination thereof. In addition, the storage 1p-40 can be configured in multiple memories.

[0294] The controller 1p-50 can control the overall operation of the base station. For example, the controller 1p-50 can send and receive signals through the baseband processor 1p-20 and the RF processor 1p-10 or through the communicator 1p-30. In addition, the controller 1p-50 may include a multi-connection processor 1p-52. The controller 1p-50 can record data on the storage 1p-40 and read data from the storage 1p-40. In this regard, the controller 1p-50 may include at least one processor. In addition, at least one component in the base station may be embodied in a chip.

[0295] In the next generation of wireless communication systems, base stations with various radio access technologies may be arranged in a complex manner. For example, a UMTS (3G) base station, an LTE base station connected to an EPC (LTE core network), or an NR (5G) base station connected to a 5GC (NR or 5G core network) can provide services to the UE. When the UE performs switching between various radio access technologies, it is necessary to reset all (pieces of) configuration information of the PHY layer, MAC layer, RLC layer or PDCP layer suitable for different radio access technologies. Therefore, when the base station indicates switching, the overhead of each layer of configuration information of each bearer (PHY layer, MAC layer, RLC layer or PDCP layer) of the UE will also increase, and the UE needs to clear all (pieces of) configuration information and reset the configuration information.

[0296] According to the present disclosure, in a next generation wireless communication system in which base stations supporting different radio access technologies provide services to UEs, a method is proposed for maintaining and unchangedly using configuration information shared between different radio access technologies when the base station instructs the UE to perform a switch between different radio access technologies (inter-RAT switch). In particular, according to some embodiments of the present disclosure, the base station may define and use an indicator (e.g., fullConfig) that instructs the UE whether to release all currently configured bearer configuration information and reconfigure the bearer configuration information, or to store information used in common by the source base station and the target base station without releasing the information. According to some embodiments of the present disclosure, the indicator may be a redefined indicator or may be a previously used indicator.

[0297] As described above, by instructing the UE to store and reuse configuration information shared between a source base station and a target base station during handover between different radio access technologies, unnecessary overhead and unnecessary operations of the UE can be reduced.

[0298] Hereinafter, specific instructions of a base station as well as specific base station operations and specific UE operations corresponding to the specific base station operations according to an embodiment of the present disclosure will be described.

[0299] Figure 2AA schematic diagram showing the structure of an LTE system according to an embodiment of the present disclosure.

[0300] refer to Figure 2A , the RAN of the LTE system may include eNB, NB or base station 2a-05, 2a-10, 2a-15 and 2a-20, MME2 2a-25 and S-GW 2a-30. UE or terminal 2a-35 may access an external network via eNB 2a-05, 2a-10, 2a-15 or 2a-20 and S-GW 2a-30.

[0301] exist Figure 2A In the present invention, each of eNB 2a-05, 2a-10, 2a-15 and 2a-20 can correspond to an existing NB of UMTS. eNB 2a-05, 2a-10, 2a-15 or 2a-20 can be connected to UE 2a-35 through a radio channel, and can perform complex functions compared with existing NBs. Because all user service data including real-time services such as VoIP are served through shared channels in the LTE system, an entity is required for collating the buffer status information, available transmission power status information, channel status information, etc. of the UE and performing scheduling, and each of eNB 2a-05, 2a-10, 2a-15 and 2a-20 serves as such an entity. A single eNB can generally control multiple cells. For example, the LTE system can use a radio access technology such as orthogonal frequency division multiplexing (OFDM) to achieve a data rate of 100Mbps at a bandwidth of 20MHz. The LTE system can also use AMC to determine the modulation scheme and channel coding rate according to the channel state of UE 2a-35. S-GW 2a-30 is an entity for providing data bearers and can configure or release data bearers under the control of MME 2a-25. MME 2a-25 is an entity for performing mobility management functions and various control functions for UE 2a-35 and can be connected to eNB2a-05, 2a-10, 2a-15 and 2a-20.

[0302] Figure 2B A schematic diagram showing a radio protocol architecture in an LTE system according to an embodiment of the present disclosure.

[0303] refer to Figure 2B , the radio protocol architecture of the LTE system may include PDCP layers 2b-05 and 2b-40, RLC layers 2b-10 and 2b-35, and MAC layers 2b-15 and 2b-30 for UE and eNB respectively. The PDCP layer 2b-05 or 2b-40 is responsible for IP header compression / decompression, etc. The main functions of the PDCP layer 2b-05 or 2b-40 can be summarized as follows.

[0304] -Header compression and decompression: ROHC only

[0305] -Transmission of user data

[0306] - For RLC AM, in-sequence delivery of upper layer PDUs during PDCP re-establishment

[0307] - For split bearers in DC (supported only for RLC AM): PDCP PDU routing for transmission and PDCP PDU reordering for reception

[0308] - For RLC AM, repeat detection of lower layer SDUs during PDCP re-establishment

[0309] - PDCP SDU retransmission at handover for split bearers in DC, and PDCP PDU retransmission during PDCP data recovery for RLC AM,

[0310] -Encryption and decryption

[0311] - Timer-based SDU discard in uplink

[0312] The RLC layer 2b-10 or 2b-35 may perform, for example, an ARQ operation by reconfiguring the PDCP PDU to an appropriate size. The main functions of the RLC layer 2b-10 or 2b-35 may be summarized as follows.

[0313] -Transmission of upper layer PDU

[0314] - Error correction via ARQ (for AM data transmission only)

[0315] - Concatenation, segmentation and reassembly of RLC SDUs (for UM and AM data transport only)

[0316] - Re-segmentation of RLC data PDU (for AM data transmission only)

[0317] - Reorder RLC data PDUs (only for UM and AM data transmission)

[0318] - Duplicate detection (for UM and AM data transmission only)

[0319] -Protocol error detection (for AM data transmission only)

[0320] -RLC SDU discard (only for UM and AM data transmission)

[0321] -RLC re-establishment

[0322] The MAC layer 2b-15 or 2b-30 is connected to a plurality of RLC layers configured for a single UE and can multiplex RLC PDUs to and demultiplex RLC PDUs from the MAC PDUs. The main functions of the MAC layer 2b-15 or 2b-30 can be summarized as follows.

[0323] - Mapping between logical channels and transport channels

[0324] - Multiplex MAC SDUs belonging to one or different logical channels into TBs delivered to the physical layer on the transport channel, and demultiplex MAC SDUs belonging to one or different logical channels from TBs from the physical layer on the transport channel

[0325] -Dispatch information report

[0326] - Error correction via HARQ

[0327] - Priority handling between logical channels of a UE

[0328] - Priority handling between UEs through dynamic scheduling

[0329] -MBMS service identification

[0330] -Transmission format selection

[0331] -filling

[0332] The PHY layer 2b-20 or 2b-25 may channel-code and modulate the upper layer data into OFDM symbols and transmit the OFDM symbols through a radio channel, or demodulate the OFDM symbols received through a radio channel and channel-decode the OFDM symbols and deliver them to the upper layer.

[0333] Figure 2C A schematic diagram showing the structure of a next generation wireless communication system according to an embodiment of the present disclosure.

[0334] refer to Figure 2C , the RAN of the next generation wireless communication system (e.g., NR or 5G system) may include NR NB or NRgNB 2c-10 and NR CN or NR CN 2c-05. NR UE or UE 2c-15 may access the external network through NR gNB 2c-10 and NR CN 2c-05.

[0335] exist Figure 2CIn the present invention, the NR gNB 2c-10 may correspond to the eNB of the existing LTE system. The NR gNB 2c-10 is connected to the NR UE 2c-15 through a radio channel and may provide better services compared to the existing NB. Because all user service data are served through shared channels in the next generation wireless communication system, an entity is required for collating the UE's buffer status information, available transmit power status information, channel status information, etc. and performing scheduling, and such operations may be performed by the NR gNB 2c-10. A single NR gNB 2c-10 may control multiple cells. In the next generation wireless communication system, a bandwidth greater than the maximum bandwidth of LTE may be given to achieve the current ultra-high data rate, and beamforming technology and OFDM may additionally be used together as radio access technology.

[0336] The next generation wireless communication system can also use AMC to determine the modulation scheme and channel coding rate according to the channel state of the NR UE 2a-15. NR CN 2c-05 can perform functions such as mobility support, bearer setting and QoS setting. NRCN 2c-05 is an entity for performing mobility management functions and various control functions for UE 2c-15, and can be connected to multiple NR gNB 2c-10. The next generation wireless communication system can cooperate with the existing LTE system, and the NR CN 2c-05 can be connected to the MME 2c-25 through a network interface. The MME 2c-25 can be connected to the existing eNB 2c-30.

[0337] refer to Figure 2C , the situation where macro cells and pico cells coexist can be considered. A macro cell is a cell controlled by a macro base station, and can provide services in a wider area. On the other hand, a pico cell is a cell controlled by a secondary base station, a SeNB, or an SgNB, and provides services in a very small area compared to a general macro cell. There is no strict criterion for distinguishing between macro cells and pico cells, but for example, the radius of the area of ​​a macro cell may be about 500 meters, and the radius of the area of ​​a pico cell may be about tens of meters. According to an embodiment of the present disclosure, a cell may include a pico cell and a macro cell. In this case, the macro cell may be an LTE base station (MeNB) or an NR base station (MgNB), and the pico cell may be an NR base station (SgNB) or an LTE base station (SeNB). In particular, a 5G base station supporting a pico cell can use a frequency band equal to or greater than 6 GHz.

[0338] In an embodiment of the present disclosure, the situation of coexistence of macro cells can be considered. A macro cell is a cell controlled by a macro base station and can provide services in a wider area. In this case, the macro cell may include an LTE base station (MeNB) and an LTE base station (SeNB). According to another embodiment of the present disclosure, the macro cell may include an LTE base station (MeNB) and an NR base station (SgNB). According to another embodiment of the present disclosure, the macro cell may include an NR base station (MgNB) and an LTE base station (SeNB). According to another embodiment of the present disclosure, the macro cell may include an NR base station (MgNB) and an NR base station (SgNB).

[0339] Figure 2D A schematic diagram showing a radio protocol architecture of a next generation wireless communication system according to an embodiment of the present disclosure.

[0340] refer to Figure 2D The radio protocol architecture of the next generation wireless communication system includes NRSDAP layers 2d-01 and 2d-45, NR PDCP layers 2d-05 and 2d-40, NR RLC layers 2d-10 and 2d-35, and NR MAC layers 2d-15 and 2d-30 for UE and NR gNB respectively.

[0341] The main functions of NR SDAP layers 2d-01 and 2d-45 may include some of the following functions.

[0342] -Transmission of user plane data

[0343] - Mapping between QoS flows and Data Radio Bearers (DRBs) for both DL and UL

[0344] -Mark QoS flow ID in DL and UL packets

[0345] - Reflective QoS flow to DRB mapping for UL SDAP PDU

[0346] For the SDAP layer, for each PDCP layer, bearer or logical channel, the UE can receive settings about whether to use the header of the SDAP layer or the function of the SDAP layer through an RRC message. When setting the SDAP header, the UE can instruct the non-access layer (NAS) of the SDAP header to reflect the QoS 1-bit indicator and the access layer (AS) to reflect the QoS 1-bit indicator to update or reset the mapping information about the data bearer and QoS flow of UL and DL. The SDAP header may include a QoS flow ID indicating the QoS. The QoS information can be used as data processing priority information, scheduling information, etc. for supporting smooth services.

[0347] The main functions of NR PDCP layer 2d-05 or 2d-40 may include some of the following functions.

[0348] -Header compression and decompression: ROHC only

[0349] -Transmission of user data

[0350] - Deliver upper layer PDUs in sequence

[0351] - Out-of-order delivery of upper layer PDUs

[0352] - Reordering of received PDCP PDUs

[0353] - Duplicate detection of lower layer SDU

[0354] -Retransmitted PDCP SDU

[0355] -Encryption and decryption

[0356] - Timer-based SDU discard in uplink

[0357] The reordering function of the NR PDCP layer 2d-05 or 2d-40 (for reordering of received PDCP PDUs) may include a function of indicating that the PDCP PDUs received from the lower layer are to be reordered based on the PDCP sequence number (SN). The reordering function of the NR PDCP layer 2d-05 or 2d-40 (for reordering of received PDCP PDUs) may include a function of delivering the reordered data to the upper layer in sequence, a function of delivering the reordered data immediately without considering the sequence, a function of recording missing PDCP PDUs by reordering the PDCP PDUs, a function of reporting status information of the missing PDCP PDUs to the transmitter, and a function of requesting retransmission of the missing PDCP PDUs.

[0358] The main functions of the NR RLC layer 2d-10 or 2d-35 may include some of the following functions.

[0359] -Transmission of upper layer PDU

[0360] - Deliver upper layer PDUs in sequence

[0361] - Out-of-order delivery of upper layer PDUs

[0362] - Error correction via ARQ

[0363] - Concatenate, segment and reassemble RLC SDUs

[0364] - Re-segmentation of RLC data PDUs

[0365] - Reorder RLC data PDUs

[0366] - Duplicate detection

[0367] -Protocol error detection

[0368] -RLC SDU discarded

[0369] -RLC re-establishment

[0370] The in-sequence delivery function of the NR RLC layer 2d-10 or 2d-35 may represent a function of delivering the RLC SDU received from the lower layer to the upper layer in sequence. The in-sequence delivery function of the NR RLC layer 2d-10 or 2d-35 may include a function of reassembling the segmented RLC SDUs and delivering the RLC SDUs when receiving multiple RLC SDUs segmented from the RLC SDU, a function of reordering the received RLC PDUs based on the RLC SN or PDCPSN, a function of recording the missing RLC PDUs by reordering the RLC PDUs, a function of reporting the status information of the missing RLC PDUs to the transmitter, a function of requesting retransmission of the missing RLC PDUs, a function of delivering only the RLC SDUs before the missing RLC SDUs to the upper layer in sequence when there are missing RLC SDUs, a function of delivering all RLC SDUs received before the timer starts in sequence to the upper layer when a timer expires despite the presence of missing RLC SDUs, and a function of delivering all RLC SDUs received before the current time in sequence to the upper layer when a timer expires despite the presence of missing RLC SDUs. In addition, the NR RLC layer 2d-10 or 2d-35 can process the RLC PDU in the order of reception (in the order of arrival regardless of the sequence number) and deliver the RLC PDU to the PDCP entity out of order (out-of-order delivery), and reassemble the segments received or stored in the buffer into a complete RLC PDU, and process and deliver the RLC PDU to the PDCP layer. The NR RLC layer 2d-10 or 2d-35 may not have a cascading function, and the cascading function may be performed by the NR MAC layer 2d-15 or 2d-30 or be replaced by a multiplexing function of the NR MAC layer 2d-15 or 2d-30.

[0371] The out-of-order delivery of the NR RLC layer 2d-10 or 2d-35 may refer to a function of delivering the RLC SDU received from the lower layer to the upper layer immediately out of sequence. The out-of-order delivery function of the NR RLC layer 2d-10 or 2d-35 may include a function of reassembling the segmented RLC SDU and delivering the RLC SDU when multiple RLC SDUs segmented from the RLC SDU are received, and a function of storing the RLC SN or PDCP SN of the received RLC PDU and recording the missing RLC PDU by sorting the RLC PDU.

[0372] The NR MAC layer 2d-15 or 2d-30 can be connected to multiple NR RLC layers 2d-10 or 2d-35 configured for a single UE, and the main functions of the NR MAC layer 2d-15 or 2d-30 may include at least some of the following functions.

[0373] - Mapping between logical channels and transport channels

[0374] -Multiplexing / demultiplexing MAC SDU

[0375] -Dispatch information report

[0376] - Error correction via HARQ

[0377] - Priority handling between logical channels of a UE

[0378] - Prioritize UEs through dynamic scheduling

[0379] -MBMS service identification

[0380] -Transmission format selection

[0381] -filling

[0382] The PHY layer 2d-20 or 2d-25 can channel-code and modulate the upper layer data into OFDM symbols and send the OFDM symbols through the radio channel, or demodulate the OFDM symbols received through the radio channel and channel-decode the OFDM symbols and deliver them to the upper layer.

[0383] Figure 2E A schematic diagram showing RRC modes of a UE belonging to a next generation wireless communication system and conversion relationships between modes according to an embodiment of the present disclosure is shown. The features of each RRC mode of the UE are as follows.

[0384] RRC_IDLE:

[0385] The UE may perform DRX operation according to the configuration related to DRX operation configured by the upper layer.

[0386] The UE may perform inter-cell mobility based on the base station configuration.

[0387] The UE may monitor SMS by using the P-RNTI transmitted from the DCI. In addition, the UE may monitor the paging channel for the core network-based paging signal by using the 5G-S-TMSI. In addition, the UE may perform a measurement or reselection procedure on a neighboring cell. In addition, the UE may receive system information or, when supported, request the base station to send system information.

[0388] RRC_INACTIVE:

[0389] The UE may perform a DRX operation according to a setting related to the DRX operation from an upper layer or an RRC layer.

[0390] The UE may perform inter-cell mobility based on the base station configuration.

[0391] The UE may store the UE inactive AS context.

[0392] The UE may be configured via the RRC layer for the RAN-based notification area.

[0393] The UE can send or receive unicast data.

[0394] The UE can monitor SMS by using the P-RNTI sent from the DCI according to the configuration. In addition, the UE can monitor the paging channel for the core network-based paging signal by using the 5G-S-TMSI, and can monitor the paging channel for the RAN-based paging signal using the full-RNTI. In addition, the UE can perform a measurement or reselection procedure on a neighboring cell. In addition, the UE can perform a RAN-based notification area update procedure periodically or when outside the RAN-based notification area. In addition, the UE can receive system information or, when supported, request the base station to send system information.

[0395] RRC_CONNECTED:

[0396] The UE may store the AS context.

[0397] The UE can send or receive unicast data.

[0398] The UE can operate at the lower layer according to the DRX set by the base station.

[0399] A UE supporting CA can use at least one Scell ​​or SpCell simultaneously.

[0400] A UE supporting DC can use at least one SCG or MCG simultaneously.

[0401] The UE may perform inter-cell mobility in NR or between NR-LTE according to the indication of the base station. Alternatively, the UE may perform inter-cell mobility in NR or between NR-LTE according to the determination of the UE based on the base station configuration.

[0402] The UE may monitor the SMS by using the P-RNTI transmitted from the DCI. The UE may monitor the control channel to determine whether there is scheduling data. The UE may perform channel measurement and send the measurement result to the base station. In addition, the UE may perform measurement or reselection procedures on neighboring cells. In addition, the UE may receive system information.

[0403] Figure 2F A schematic diagram for describing a process in which a UE establishes a connection with a network by transitioning from an RRC idle mode to an RRC connected mode according to an embodiment of the present disclosure is shown.

[0404] refer to Figure 2F , when a UE that sends or receives data in RRC connected mode does not send or receive data for a certain reason or within a certain period of time, the gNB may send an RRCConnectionRelease message to the UE to transition to RRC idle mode (operation 2f-01). Thereafter, when data to be sent is generated, a UE that currently has no connection established (hereinafter referred to as an idle mode UE) may perform an RRC connection establishment procedure with the gNB. The UE may establish reverse transmission synchronization with the eNB through a random access procedure and send an RRCConnectionRequest message to the gNB (operation 2f-05). The RRCConnectionRequest message may include an identifier of the UE, an establishment cause, etc.

[0405] The gNB may send an RRCConnectionSetup message so that the UE establishes an RRC connection (operation 2f-10). The RRCConnectionSetup message may include configuration information for each service / bearer / RLC layer or for each logical channel or bearer, and may include information about whether to use ROHC for each bearer / logical channel, ROHC configuration information (e.g., ROHC version or initial information), statusReportRequired information (information for instructing the UE to perform PDCP status reporting by the gNB), and drb-ContinueROHC information (configuration information for maintaining and unchanged using the ROHC configuration information and included and sent in the PDCP layer configuration information (pdcp-config)). In addition, the RRCConnectionSetup message may include RRC connection configuration information, etc. The bearer used for the RRC connection is also called SRB and may be used during the transmission and reception of RRC messages which are control messages between the UE and the gNB.

[0406] The UE that establishes the RRC connection may send an RRCConnectionSetupComplete message to the gNB (operation 2f-15). The RRCConnectionSetupComplete message may include a control message such as a SERVICE REQUEST message for requesting the MME to configure a bearer for a service for the UE. The gNB may send a SERVICE REQUEST message included in the RRCConnectionSetupComplete message to the MME (operation 2f-20), and the MME may determine whether to provide the service requested by the UE. As a result of the determination, when the service requested by the UE is to be provided, the MME may send an INITIAL CONTEXT SETUP REQUEST message to the gNB (operation 2f-25). The INITIAL CONTEXT SETUP REQUEST message may include QoS information to be applied when configuring the DRB, security information to be applied to the DRB (e.g., security keys, security algorithms, etc.), etc. The gNB may exchange SecurityModeCommand messages (operation 2f-30) and SecurityModeComplete messages (operation 2f-35) with the UE to configure the security mode. After configuring the security mode, the gNB may send an RRCConnectionReconfiguration message (operation 2f-40) to the UE.

[0407] The RRCConnectionReconfiguration message may include configuration information for each service / bearer / RLC layer or for each logical channel or bearer, and may include information on whether to use ROHC for each bearer / logical channel, ROHC configuration information (e.g., ROHC version or initial information), statusReportRequired information (information for instructing the UE to perform PDCP status reporting by the gNB), and drb-ContinueROHC information (configuration information for maintaining and unchanged using the ROHC configuration information and included and sent in the PDCP layer configuration information (pdcp-config)). In addition, the RRCConnectionReconfiguration message may include RRC connection configuration information, etc. The bearer used for the RRC connection is also called SRB and can be used during the transmission and reception of RRC messages as control messages between the UE and the gNB. The following [Table 2] is an example of PDCP configuration information included in the RRC connection reconfiguration message.

[0408]

Table 2

[0409]

[0410] In addition, the RRCConnectionReconfiguration message may include configuration information about the DRB to process user data, and the UE may configure the DRB by using the configuration information and send an RRCConnectionReconfigurationComplete message to the gNB (operation 2f-45). After completing the DRB configuration with the UE, the gNB sends an INITIAL CONTEXT SETUP COMPLETE message to the MME (operation 2f-50), and upon reception, the MME may exchange an S1 BEARER SETUP message and an S1 BEARER SETUP Response message with the S-GW to configure the S1 bearer (operations 2f-55 and 2f-60). The S1 bearer is a connection configured between the S-GW and the gNB for data transmission, and may correspond to the DRB in a one-to-one manner. After completing the above process, the UE may send data to or receive data from the gNB through the S-GW in operations 2f-65 and 2f-70. In this way, the general data transmission process can mainly include three steps: RRC connection establishment, security setup and DRB configuration. In addition, the gNB can send an RRCConnectionReconfiguration message to the UE to update, add or change the configuration for certain reasons (2f-75).

[0411] In addition, the RRCConnectionReconfiguration message may include an indicator (e.g., fullConfig) that instructs the UE whether to release the entire configuration information (e.g., bearer configuration information) and configure new entire configuration information, or to newly configure only some UE information in the current configuration information (e.g., configuration information of the RLC layer, MAC layer, or PHY layer). For example, when the indicator is included in the RRCConnectionReconfiguration message, the UE may release the entire bearer configuration information based on the received configuration information and reconfigure the entire UE configuration information. When the indicator is not included in the RRCConnectionReconfiguration message, the UE may store all or some of the existing UE information (e.g., configuration information of the PDCP layer or SDAP layer), and update the reconfigured configuration information as part of the current UE configuration information.

[0412] In the present disclosure, a bearer may refer to an SRB and a DRB, where an SRB stands for a signaling radio bearer and a DRB stands for a data radio bearer. An SRB may be used to transmit and receive an RRC message of an RRC layer, and a DRB may be mainly used to transmit and receive user layer data. In addition, a UM DRB may refer to a DRB of an RLC layer operating under a UM, and an AM DRB may refer to a DRB of an RLC layer operating under an AM.

[0413] Figure 2G A schematic diagram for describing a handover process in a next generation wireless communication system according to an embodiment of the present disclosure is shown.

[0414] When a periodic or specific event is met, the UE 2g-01 in the connected mode state sends cell measurement information (measurement report) to the current source gNB 2g-02 (2g-05). The source gNB 2g-02 can determine whether the UE 2g-01 is to perform a handover to a neighboring cell based on the cell measurement information. Handover is a technique for changing the source gNB 2g-02 that provides service to the UE 2g-01 in the connected mode state to another gNB (or another cell in the same gNB).

[0415] When the source gNB 2g-02 determines the handover, the source gNB 2g-02 requests the new gNB (i.e., the target gNB 2g-03) to provide services to the UE 2g-01 for the handover by sending a handover (HO) request message (2g-10). When the target gNB 2g-03 accepts the HO request, the target gNB 2g-03 sends a HO request confirm message to the source gNB 2g-02 (2g-15). After receiving the HO request confirm message, the source gNB 2g-02 sends a HO command message to the UE 2g-01 (2g-20). The HO command message is sent from the source gNB 2g-02 to the UE 2g-01 by using the RRCConnectionReconfiguration message (2g-20). After receiving the HO command message, the UE 2g-01 stops exchanging data with the source gNB 2g-02 and starts the T304 timer. When the handover of UE 2g-01 to the target gNB 2g-03 is not successful within a certain period of time, the T304 timer sets the UE 2g-01 to the original settings and sets it to the RRC idle state. When there is downlink data, the source gNB 2g-02 sends the sequence number (SN) status for the uplink / downlink data and sends the downlink data to the target gNB 2g-03 (2g-30 and 2g-35). UE 2g-01 attempts random access to the target cell (2g-40) instructed by the source gNB 2g-02. UE 2g-01 attempts random access to notify the target cell that UE 2g-01 is moving through handover, and at the same time, synchronize the uplink. For random access, UE 2g-01 sends a preamble corresponding to the preamble ID provided from the source gNB 2g-02 or a randomly selected preamble ID to the target gNB 2g-03. When a certain number of subframes have passed after sending the preamble, UE 2g-01 monitors whether a RAR message is sent from the target gNB 2g-03. The time period for monitoring whether the RAR message is sent is called the RAR window. Within a certain time, when the RAR message is received (2g-45), UE 2g-01 sends an RRCConnectionReconfigurationComplete message as a HO completion message to the target gNB 2g-03 (2g-55). After successfully receiving the RAR message from the target gNB 2g-03, UE 2g-01 stops the T304 timer (2g-50). The target gNB 2g-03 requests the MME (or S-GW or AMF) 2g-04 to change the path (2g-60 and 2g-65) in order to change the path of the bearer set in the source gNB 2g-02, and notifies the source gNB 2g-02 to release the UE context of UE 2g-01 (2g-70).Therefore, UE 2g-01 tries to receive data from the target gNB 2g-03 from the time point when the RAR window starts, and after receiving the RAR message, starts sending data to the target gNB 2g-03 while sending the RRCConnectionReconfigurationComplete message.

[0416] Figure 2H A schematic diagram for describing a conditional switching process in a next generation wireless communication system according to an embodiment of the present disclosure is shown.

[0417] When a periodic or specific event is met, the UE 2h-01 in the connected mode state sends cell measurement information (measurement report) to the current source gNB 2h-02 (2h-05). In addition, the source gNB 2h-02 can determine at least one designated gNB based on the measurement information, where the UE 2h-01 is able to perform switching to the adjacent cell. Conditional switching is a technology in which the source gNB 2h-02 providing service to the UE 2h-01 in the connected mode is changed to another gNB (or another cell of the same gNB) while the gNB provides conditions for performing switching and the UE 2h-01 performing the switching determines the time point.

[0418] When the source eNB 2h-02 determines at least one eNB related to the handover, the source eNB 2h-02 requests conditional handover by sending a conditional handover (CHO) request message to at least one designated gNB or target gNB 2h-03 that provides service to UE 2h-01 (2h-10). When the target gNB 2h-03 accepts the conditional handover request, the target gNB 2h-03 sends a CHO request confirmation message to the source gNB 2h-02 (2h-15). After receiving the CHO request confirmation message, the source gNB 2h-02 sends a CHO command message to UE 2h-01. The CHO command message is sent from the source gNB 2h-02 to UE 2h-01 by using an RRCConnectionReconfiguration message (2h-20). The CHO command may include a time during which the corresponding message is valid (Txxx timer expiration time), at least one designated gNB information (e.g., at least one of frequency information or gNB identification (ID)), or a condition for performing handover (e.g., a condition related to the channel state of the source gNB 2h-02) or at least one of the conditions related to the channel state of at least one designated gNB. After receiving the CHO command message, the UE 2h-01 starts the Txxx timer, measures at least one of the channel state with the source gNB 2h-02 or the channel state with the designated gNB, and compares the measured channel state with the condition received from the source gNB 2h-02. When the UE 2h-01 does not perform handover on the target gNB 2h-03 within a certain period of time of the Txxx timer, the UE 2h-01 releases the CHO command received from the source gNB 2h-02. The source gNB 2h-02 can send the SN status for UL / DL data and send the DL data to the target gNB 2h-03 (2h-30 and 2h-35) when there is DL data.

[0419] When UE 2h-01 determines that handover needs to be performed on one of the designated gNBs based on the conditions received from the source gNB 2h-02, UE 2h-01 attempts random access to one of the designated gNBs (target cell) as indicated by the source gNB 2h-02. Random access is performed to inform the target cell that UE 2h-01 is moving through handover and adjusting UL synchronization at the same time. For random access, UE 2h-01 sends a preamble corresponding to the preamble ID provided from the source gNB 2h-02 or a randomly selected preamble ID to the target cell. When a certain number of subframes have passed after sending the preamble, UE 2h-01 monitors whether a random access response (RAR) message is sent from the target gNB 2h-03. The monitoring period is called the RAR window. Within a certain time, when the RAR message is received (2h-45), UE 2h-01 sends the RRCConnectionReconfigurationComplete message as the HO completion message to the target gNB 2g-03 (2h-55). As described above, after successfully receiving the RAR message from the target gNB 2h-03, UE 2h-01 stops the T304 timer (2h-50).

[0420] The target gNB 2h-03 requests path modification to modify the path of the bearer set in the source gNB 2h-02 (2h-60 and 2h-65), and notifies the source gNB 2h-02 to release the UE context of UE 2h-01 (2h-70). Therefore, UE 2h-01 attempts to receive data from the target gNB 2h-03 from the time point when the RAR window starts, and after receiving the RAR message, starts sending data to the target gNB 2h-03 while sending the RRCConnectionReconfigurationComplete message.

[0421] Fig.2I A schematic diagram of a first embodiment for describing operations of a base station in a handover situation between different radio access technologies according to an embodiment of the present disclosure is shown.

[0422] refer to Fig.2I , the structure of the bearer supported in the LTE base station connected to the EPC (LTE core network) can be represented by reference numeral 2i-05, and the function of each layer can refer to Figure 2B In addition, the structure of the bearer supported in the NR base station can be represented by reference numeral 2i-10, and the function of each layer can be referred to Figure 2D The NR base station can be connected to both the EPC and the 5GC (NR core network).

[0423] like Figure 2B , Figure 2D and Fig.2I As described in, each layer of bearers supported in an LTE base station connected to the EPC and each layer of bearers supported in an NR base station may have different functions.

[0424] Therefore, the present disclosure proposes a method for releasing all (pieces) of bearer configuration information set in the UE and reconfiguring all (pieces) of bearer configuration information when a base station instructs switching between different radio access technologies (particularly, when a UE that receives a service by setting an NR base station as a source base station is instructed to switch by setting an LTE base station connected to the EPC as a target base station). In addition, in the present disclosure, a new indicator (fullConfig) may be defined in the RRCConnectionReconfiguration message to the UE to release all (pieces) of bearer configuration information set in the UE and reconfigure the entire configuration information. For example, when the indicator is included in the RRCConnectionReconfiguration message, the UE may release the entire bearer configuration information and, based on the received configuration information, reconfigure the entire UE configuration information.

[0425] In addition, the present disclosure proposes a method for releasing all (pieces) of bearer configuration information set in the terminal and reconfiguring all (pieces) of bearer configuration information when a base station instructs switching between different radio access technologies (particularly, when a UE that receives a service by setting an LTE base station connected to an EPC as a source base station is instructed to switch by setting an NR base station as a target base station). In addition, in the present disclosure, a new indicator (fullConfig) can be defined in the RRCConnectionReconfiguration message to the UE to release all (pieces) of bearer configuration information set in the UE and reconfigure the entire configuration information. For example, when the indicator is included in the RRCConnectionReconfiguration message, the UE can release the entire bearer configuration information and reconfigure the entire UE configuration information based on the received configuration information.

[0426] Figure 2J A schematic diagram of a second embodiment for describing operations of a base station in a handover situation between different radio access technologies according to an embodiment of the present disclosure is shown.

[0427] refer to Figure 2J , the structure of the bearer supported in the LTE base station connected to the 5GC (LTE core network) can be represented by reference numeral 2j-05, and the function of each layer can refer to Figure 2B and Figure 2DHere, each bearer supported in the LTE base station connected to the 5GC may be configured and use the NR PDCP layer (rather than the LTE PDCP layer) as the PDCP layer. In addition, the structure of the bearer supported in the NR base station may be represented by reference numeral 2j-10, and the function of each layer may refer to Figure 2D Here, the NR base station can be connected to both the EPC and the 5GC (NR core network).

[0428] As reference Figure 2B , Figure 2D and Fig.2I As described, each layer of the bearer supported in the LTE base station connected to the 5GC and each layer of the bearer supported in the NR base station may have different functions, but in the case of the PDCP layer, both the LTE base station connected to the 5GC and the NR base station may support the NR PDCP layer. In addition, because the SDAP layer includes mapping information between the QoS flow and the bearer from the 5GC core network, the mapping information between the QoS flow and the bearer from the 5GC core network may be useful configuration information for both the LTE base station connected to the 5GC and the NR base station.

[0429] Therefore, the present disclosure proposes a method for storing existing configuration information (e.g., configuration information of the PDCP layer or configuration information of the SDAP layer) and reconfiguring some bearer configuration information without releasing all (pieces) of bearer configuration information set in the UE when the base station instructs switching between different radio access technologies (in particular, when the switching is instructed for a UE that receives services by setting the NR base station as the source base station and by setting the LTE base station connected to the 5GC as the target base station). In addition, in the present disclosure, a new indicator (fullConfig) can be defined in the RRCConnectionReconfiguration message to the UE so as to reconfigure only some information without releasing all (pieces) of bearer configuration information configured in the UE. For example, when the indicator is not included in the RRCConnectionReconfiguration message, the UE can store or maintain the entire or some information (e.g., configuration information of the PDCP layer or the SDAP layer) among the existing UE information, and update the reconfigured configuration information as part of the current UE configuration information.

[0430] In addition, the present disclosure proposes a method for storing or maintaining existing configuration information (e.g., configuration information of the PDCP layer or configuration information of the SDAP layer) and reconfiguring some bearer configuration information without releasing all (pieces) of bearer configuration information set in the UE when the base station instructs switching between different radio access technologies (in particular, when the switching is instructed by setting the NR base station as the target base station for a UE that receives services by setting the LTE base station connected to the 5GC as the source base station). In addition, in the present disclosure, a new indicator (fullConfig) can be defined in the RRCConnectionReconfiguration message to instruct the UE to reconfigure only some information without releasing all (pieces) of bearer configuration information configured in the UE. For example, when the indicator is not included in the RRCConnectionReconfiguration message, the UE can store or maintain the entire or some information (e.g., configuration information of the PDCP layer or the SDAP layer) among the existing UE information, and update the reconfigured configuration information as part of the current UE configuration information.

[0431] Hereinafter, operations of a UE when the UE is instructed to switch between different radio access technologies according to operations of the above-described base station are described.

[0432] -When the UE receives an RRC message (e.g., an RRCConnectionReconfiguration message or an RRCResume message) and successfully completes mobility and leaves the NR base station (or NR radio access technology),

[0433] - When the UE receives an RRC message (e.g., an RRCConnectionReconfiguration message or an RRCResume message) and successfully completes mobility and leaves an LTE base station (or LTE radio access technology),

[0434] ■UE resets the MAC layer.

[0435] ■UE stops all running timers.

[0436] ■UE releases the currently configured security configuration information.

[0437] ■UE releases the configuration information of the currently configured RLC layer or MAC layer.

[0438] ■When there is no instruction to release the entire UE configuration information (when there is no instruction or the indicator (fullConfig) proposed in the present disclosure is not included),

[0439] ◆The UE stores and maintains the configuration information of the PDCP layer or SDAP layer configured in the source base station (or source radio access technology) to which the UE currently accesses. The maintained or stored configuration information of the PDCP layer or SDAP layer can be applied to or used for the target base station (or radio access technology).

[0440] ■ Otherwise, when the instruction releases the entire UE configuration information (when indicating or including the indicator (fullConfig) proposed in the present disclosure),

[0441] ◆The UE releases the current configuration of the PDCP layer or SDAP layer for all bearers.

[0442] Figure 2K A schematic diagram showing the operation of a UE according to an embodiment of the present disclosure.

[0443] According to some embodiments of the present disclosure, when the UE receives an RRC message (e.g., an RRCConnectionReconfiguration message or an RRCResume message) (2k-05), the UE may identify whether the received RRC message includes an indicator (fullConfig) (2k-15). When there is no instruction to release the entire UE configuration information (when there is no instruction or no Figure 2G or Figure 2H When the indicator (fullConfig) proposed in (2k-20) is displayed, the UE can store and maintain at least some configuration information of the PDCP layer or SDAP layer configured in the source base station (or radio access technology) to which the UE is currently accessing. The maintained or stored configuration information of the PDCP layer or SDAP layer can be applied to the target base station (or radio access technology) (2k-30). When at least some configuration information of the PDCP layer or SDAP layer to be used in the target base station is received from the target base station or the source base station, the UE can apply the received configuration information (2k-40). For example, the UE can update the configuration information of the PDCP layer or SDAP layer by applying at least some of the received configuration information.

[0444] According to the embodiment of the present disclosure, when the UE is configured to refer to Figure 2MIn the described electronic device and the source base station is an LTE base station and the target base station is an NR base station, the first communication processor 2m-12 may be able to send at least some configuration information of the PDCP layer or SDAP layer related to the existing source base station to the second communication processor 2m-14. According to an embodiment of the present disclosure, the first communication processor 2m-12 may send at least some configuration information of the PDCP layer or SDAP layer to the second communication processor 2m-14, and store the configuration information of the PDCP layer or SDAP layer. According to another embodiment of the present disclosure, the first communication processor 2m-12 may send at least some configuration information of the PDCP layer or SDAP layer to the second communication processor 2m-14, and release the configuration information of the PDCP layer or SDAP layer.

[0445] According to another embodiment of the present disclosure, when the UE is configured to refer to Figure 2M In the electronic device described and the source base station is an NR base station and the target base station is an LTE base station, the second communication processor 2m-14 may send at least some configuration information of the PDCP layer or SDAP layer related to the existing source base station to the first communication processor 2m-12. According to an embodiment of the present disclosure, the second communication processor 2m-14 may send at least some configuration information of the PDCP layer or SDAP layer to the first communication processor 2m-12, and store the configuration information of the PDCP layer or SDAP layer. According to another embodiment of the present disclosure, the second communication processor 2m-14 may send at least some configuration information of the PDCP layer or SDAP layer to the first communication processor 2m-12, and release the configuration information of the PDCP layer or SDAP layer.

[0446] Otherwise, when the command releases the entire UE configuration information (when the command or indication Figure 2G or Figure 2H When the UE receives at least some of the configuration information of the PDCP layer or SDAP layer to be used in the target base station from the target base station or the source base station, the UE may apply the received configuration information (2k-35). For example, the UE may update the entire configuration information of the PDCP layer or SDAP layer by applying at least some of the received configuration information.

[0447] According to the embodiment of the present disclosure, when the UE is configured to refer to Figure 2MIn the electronic device described, when the source base station is an LTE base station and the target base station is an NR base station, the first communication processor 2m-12 may be able to store configuration information of the PDCP layer or SDAP layer related to the existing source base station. According to another embodiment of the present disclosure, the first communication processor 2m-12 may be able to release configuration information of the PDCP layer or SDAP layer related to the existing source base station.

[0448] Figure 2L A schematic diagram showing the structure of a UE according to an embodiment of the present disclosure.

[0449] refer to Figure 2L , the UE includes an RF processor 21-10, a baseband processor 21-20, a storage 21-30, and a controller 21-40. However, the UE is not limited thereto, and may include more Figure 2L More or fewer components than those shown.

[0450] The RF processor 21-10 can perform functions for sending and receiving signals through a radio channel, such as signal band conversion and amplification. That is, the RF processor 21-10 up-converts the baseband signal provided by the baseband processor 21-20 into an RF band signal and transmits the RF band signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processor 21-10 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC. Although Figure 2L Only a single antenna is shown in the figure, but the UE may include multiple antennas. The RF processor 2l-10 may include multiple RF chains. The RF processor 2l-10 can perform beamforming. For beamforming, the RF processor 2l-10 can adjust the phase and amplitude of signals sent or received through multiple antennas or antenna elements. The RF processor 2l-10 can perform MIMO and can receive multiple layers of data in MIMO operation. Under the control of the controller 2l-40, the RF processor 2l-10 can perform scanning of the receive beam by appropriately configuring multiple antennas or antenna elements, or adjust the direction and beam width of the receive beam to coordinate with the transmit beam.

[0451] The baseband processor 21-20 can convert between baseband signals and bit streams based on the physical layer specifications of the system. For example, for data transmission, the baseband processor 21-20 generates complex symbols by encoding and modulating the transmission bit stream. For data reception, the baseband processor 21-20 can reconstruct the received bit stream by demodulating and decoding the baseband signal provided by the RF processor 21-10. For example, according to the OFDM scheme, for data transmission, the baseband processor 21-20 generates complex symbols by encoding and modulating the transmission bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols by performing IFFT and CP insertion. For data reception, the baseband processor 21-20 can split the baseband signal provided by the RF processor 21-10 into units of OFDM symbols, reconstruct the signal mapped to the subcarrier by performing FFT, and then reconstruct the received bit stream by demodulating and decoding the signal.

[0452] The baseband processor 21-20 and the RF processor 21-10 send and receive signals as described above. In this way, each of the baseband processor 21-20 and the RF processor 21-10 may also be referred to as a transmitter, a receiver, a transceiver, or a communicator. At least one of the baseband processor 21-20 or the RF processor 21-10 may include multiple communication modules to support a variety of different radio access technologies. In addition, at least one of the baseband processor 21-20 or the RF processor 21-10 may include multiple communication modules to process signals of different frequency bands. For example, different radio access technologies may include LTE networks, NR networks, etc. Different frequency bands may include SHF (e.g., 2.5GHz and 5GHz) bands and mmWave (e.g., 60GHz) bands. The UE may send or receive signals to or from a base station using the baseband processor 21-20 and the RF processor 21-10, and the signal may include control information and data.

[0453] The storage 21-30 may store data for the operation of the UE, such as basic programs, applications, and configuration information. The storage 21-30 may provide the stored data according to the request of the controller 21-40. The storage 21-30 may be configured in a storage medium such as a ROM, RAM, hard disk, CD-ROM or DVD, or a combination thereof. In addition, the storage 21-30 may be configured in a plurality of memories.

[0454] The controller 21-40 can control the overall operation of the UE. For example, the controller 21-40 can send and receive signals through the baseband processor 21-20 and the RF processor 21-10. The controller 21-40 can record data on the storage 21-30 and read data from the storage 21-30. In this regard, the controller 21-40 may include at least one processor. For example, the controller 21-40 may include a CP for controlling communications and an AP for controlling an upper layer such as an application. In addition, the controller 21-40 may include a multi-connection processor 21-42. In addition, at least one component in the UE may be embodied in a chip.

[0455] Figure 2M A schematic diagram showing the structure of an electronic device 2m-01 for supporting traditional network communications and 5G network communications according to an embodiment of the present disclosure is shown.

[0456] refer to Figure 2M , the electronic device 2m-01 may include a first communication processor 2m-12, a second communication processor 2m-14, a first RFIC 2m-22, a second RFIC 2m-24, a third RFIC 2m-26, a fourth RFIC 2m-28, a first RFFE 2m-32, a second RFFE 2m-34, a first antenna module 2m-42, a second antenna module 2m-44 and an antenna 2m-48. The electronic device 2m-01 may also include a processor 2m-20 and a memory 2m-30. The network 2m-99 may include a first network 2m-92 and a second network 2m-94. According to another embodiment of the present disclosure, the electronic device 2m-01 may also include Figure 2M At least one component among those shown, and the network 2m-99 may also include at least one other network. According to an embodiment of the present disclosure, the first communication processor 2m-12, the second communication processor 2m-14, the first RFIC 2m-22, the second RFIC 2m-24, the fourth RFIC 2m-28, the first RFFE 2m-32 and the second RFFE 2m-34 may form at least a part of the wireless communication module 2m-10. According to another embodiment of the present disclosure, the fourth RFIC 2m-28 may be omitted or may be included as part of the third RFIC 2m-26.

[0457] The first communication processor 2m-12 may support the establishment of a communication channel for a frequency band to be used for wireless communication with the first network 2m-92, and may support traditional network communication through the established communication channel. According to various embodiments of the present disclosure, the first network 2m-92 may be a traditional network including a 2G, 3G, 4G or LTE network. The second communication processor 2m-14 may support the establishment of a communication channel corresponding to an allocated frequency band (e.g., about 6 GHz to about 60 GHz) among the frequency bands to be used for wireless communication with the second network 2m-94, and may support 5G network communication through the established communication channel. According to various embodiments of the present disclosure, the second network 2m-94 may be a 5G network defined by 3GPP. In addition, according to an embodiment of the present disclosure, the first communication processor 2m-12 or the second communication processor 2m-14 may support the establishment of a communication channel corresponding to another allocated frequency band (e.g., about 6 GHz or lower) among the frequency bands to be used for wireless communication with the second network 2m-94, and may support 5G network communication through the established communication channel. According to an embodiment of the present disclosure, the first communication processor 2m-12 and the second communication processor 2m-14 can be implemented in a single chip or a single package. According to various embodiments of the present disclosure, the first communication processor 2m-12 or the second communication processor 2m-14 can be implemented in a single chip or a single package with the processor 2m-20, an auxiliary processor or a communication module.

[0458] During transmission, the first RFIC 2m-22 can convert a baseband signal generated by the first communication processor 2m-12 into an RF signal of about 700 MHz to about 3 GHz for a first network 2m-92 (e.g., a legacy network). During reception, the RF signal can be obtained from the first network 2m-92 (e.g., a legacy network) via an antenna (e.g., a first antenna module 2m-42) and pre-processed by an RFFE (e.g., a first RFFE 2m-32). The first RFIC 2m-22 can convert the pre-processed RF signal into a baseband signal processed by the first communication processor 2m-12.

[0459] During transmission, the second RFIC 2m-24 can convert the baseband signal generated by the first communication processor 2m-12 or the second communication processor 2m-14 into an RF signal (hereinafter referred to as a 5G Sub6RF signal) of the Sub6 frequency band (e.g., approximately 6 GHz or lower) for the second network 2m-94 (e.g., a 5G network). During reception, the 5G Sub6 RF signal can be obtained from the second network 2m-94 (e.g., a 5G network) via an antenna (e.g., a second antenna module 2m-44) and pre-processed by an RFFE (e.g., a second RFFE 2m-34). The second RFIC 2m-24 can convert the pre-processed 5G Sub6RF signal into a baseband signal processed by a communication processor corresponding to the first communication processor 2m-12 or the second communication processor 2m-14.

[0460] During transmission, the third RFIC 2m-26 may convert a baseband signal generated by the second communication processor 2m-14 into an RF signal (hereinafter referred to as a 5G Above6 RF signal) of a 5G Above6 frequency band (e.g., approximately 6 GHz to approximately 60 GHz) to be used for a second network 2m-94 (e.g., a 5G network). During reception, the 5G Above6 RF signal may be obtained from the second network 2m-94 (e.g., a 5G network) via an antenna (e.g., antenna 2m-48) and preprocessed by the third RFFE 2m-36. The third RFIC 2m-26 may convert the preprocessed 5G Above6 RF signal into a baseband signal processed by the second communication processor 2m-14. According to an embodiment of the present disclosure, the third RFFE 2m-36 may be configured as part of the third RFIC 2m-26.

[0461] According to an embodiment of the present disclosure, the electronic device 2m-01 may include a fourth RFIC 2m-28 that is separate from the third RFIC 2m-26 or as part of the third RFIC 2m-26. In this case, the fourth RFIC 2m-28 can convert the baseband signal generated by the second communication processor 2m-14 into an RF signal (hereinafter referred to as an IF signal) of an intermediate frequency (IF) band (e.g., about 9 GHz to about 11 GHz), and send the IF signal to the third RFIC 2m-26. The third RFIC 2m-26 can convert the IF signal into a 5G Above6 RF signal. During reception, the 5G Above6 RF signal can be received from the second network 2m-94 (e.g., a 5G network) via an antenna (e.g., antenna 2m-48) and converted into an IF signal by the third RFIC 2m-26. The fourth RFIC2m-28 can convert the IF signal into a baseband signal processed by the second communication processor 2m-14.

[0462] According to an embodiment of the present disclosure, the first RFIC 2m-22 and the second RFIC 2m-24 may be implemented as at least a portion of a single chip or a single package. According to an embodiment of the present disclosure, the first RFFE 2m-32 and the second RFFE 2m-34 may be implemented as at least a portion of a single chip or a single package. According to an embodiment of the present disclosure, at least one of the first antenna module 2m-42 or the second antenna module 2m-44 may be omitted or may be combined with another antenna module to process RF signals of multiple corresponding frequency bands.

[0463] According to an embodiment of the present disclosure, the third RFIC 2m-26 and the antenna 2m-48 can be arranged on the same substrate to configure the third antenna module 2m-46. For example, the wireless communication module 2m-10 or the processor 2m-20 can be arranged on a first substrate (e.g., a main PCB). In this case, the third RFIC 2m-26 can be arranged on a partial area (e.g., a bottom surface) of a second substrate (e.g., a sub-PCB) different from the first substrate, and the antenna 2m-48 can be arranged on another partial area (e.g., a top surface) of the second substrate to form a third antenna module 2m-46. According to an embodiment of the present disclosure, the antenna 2m-48 may include, for example, an antenna array for beamforming. By arranging the third RFIC 2m-26 and the antenna 2m-48 on the same substrate, the length of the transmission path between them can be reduced. Therefore, for example, the loss (e.g., attenuation) of signals in a high frequency band (e.g., about 6 GHz to about 60 GHz) for 5G network communication caused by the transmission path can be prevented. Therefore, the communication quality or speed between the electronic device 2m-01 and the second network 2m-94 (e.g., a 5G network) can be increased.

[0464] The second network 2m-94 (e.g., a 5G network) can operate independently (e.g., SA) of the first network 2m-92 (e.g., a traditional network) or connected to the first network 2m-92 (e.g., NSA). For example, the 5G network may only include an access network (e.g., 5G RAN or NG RAN) and does not include a core network (e.g., NGC). In this case, the electronic device 2m-01 can access the access network of the 5G network and access an external network (e.g., the Internet) under the control of the core network (e.g., EPC) of the traditional network. Protocol information for communicating with the traditional network (e.g., LTE protocol information) and protocol information for communicating with the 5G network (e.g., new radio (NR) protocol information) can be stored in the memory 2m-30 and accessed by another component (e.g., the processor 2m-20, the first communication processor 2m-12, or the second communication processor 2m-14).

[0465] Figure 2NA block diagram showing the structure of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0466] refer to Figure 2N , the base station may include an RF processor 2n-10, a baseband processor 2n-20, a communicator 2n-30, a storage 2n-40, and a controller 2n-50. However, the base station is not limited thereto, and may include more Figure 2N More or fewer components than those shown.

[0467] The RF processor 2n-10 can perform functions for sending and receiving signals through a radio channel, such as signal band conversion and amplification. That is, the RF processor 2n-10 up-converts the baseband signal provided by the baseband processor 2n-20 into an RF band signal and transmits the RF band signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processor 2n-10 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC. Although Figure 2N Only a single antenna is shown in the figure, but the RF processor 2n-10 may include multiple antennas. The RF processor 2n-10 may include multiple RF chains. In addition, the RF processor 2n-10 can perform beamforming. For beamforming, the RF processor 2n-10 can adjust the phase and amplitude of the signal sent or received through multiple antennas or antenna elements. The RF processor 2n-10 can perform DL MIMO by sending data of two or more layers.

[0468] The baseband processor 2n-20 can convert between baseband signals and bit streams based on the physical layer specifications of the first radio access technology. For example, for data transmission, the baseband processor 2n-20 generates complex symbols by encoding and modulating the transmission bit stream. For data reception, the baseband processor 2n-20 reconstructs the received bit stream by demodulating and decoding the baseband signal provided from the RF processor 2n-10. For example, according to the OFDM scheme, for data transmission, the baseband processor 2n-20 generates complex symbols by encoding and modulating the transmission bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols by performing IFFT and CP insertion. For data reception, the baseband processor 2n-20 can split the baseband signal provided from the RF processor 2n-10 in units of OFDM symbols, reconstruct the signal mapped to the subcarrier by performing FFT, and then reconstruct the received bit stream by demodulating and decoding the signal. The baseband processor 2n-20 and the RF processor 2n-10 send and receive signals as described above. As such, each of the baseband processor 2n-20 and the RF processor 2n-10 may also be referred to as a transmitter, a receiver, a transceiver, a communicator, or a wireless communicator. The base station may send or receive a signal to or from the UE by using the baseband processor 2n-20 and the RF processor 2n-10, and the signal may include control information and data.

[0469] The communicator 2n-30 may provide an interface for communicating with other nodes in the network. According to some embodiments of the present disclosure, the communicator 2n-30 may be a backhaul communicator.

[0470] The storage 2n-40 can store data used for the operation of the base station as described above, for example, basic programs, applications, and configuration information. In particular, the storage 2n-40 can store information about the bearer assigned to the connected UE, measurement reports sent from the connected UE, etc. The storage 2n-40 can store standard information for determining whether to provide multiple connections to the UE or release multiple connections from the UE. The storage 2n-40 can provide stored data according to the request of the controller 2n-50. The storage 2n-40 can be configured in a storage medium, such as a ROM, RAM, hard disk, CD-ROM or DVD, or a combination thereof. In addition, the storage 2n-40 can be configured in multiple memories.

[0471] The controller 2n-50 can control the overall operation of the base station. For example, the controller 2n-50 can send and receive signals through the baseband processor 2n-20 and the RF processor 2n-10 or through the communicator 2n-30. The controller 2n-50 can record data on the storage 2n-40 and read data from the storage 2n-40. In this regard, the controller 2n-50 may include at least one processor. In addition, the controller 2n-50 may include a multi-connection processor 2n-52. In addition, at least one component in the base station may be embodied in one chip.

[0472] Although the present disclosure has been described with various embodiments, various changes and modifications may occur to those skilled in the art. The present disclosure is intended to encompass such changes and modifications as fall within the scope of the appended claims.

Claims

1. A method for performing handover between different radio access technologies in wireless communication performed by a user equipment (UE), the method comprising: receiving a radio resource control (RRC) message; Identifying whether a complete configuration indicator is present in the RRC message; In the absence of a complete configuration indicator in the RRC message, configuration information of a Service Data Adaptation Protocol (SDAP) layer and a New Radio (NR) Packet Data Convergence Protocol (PDCP) layer configured in a source base station (BS) is not released; and Based on the identification that the complete configuration indicator is not present in the RRC message, the configuration information of the SDAP layer and the NR PDCP layer configured in the source BS is reused for the target BS.

2. The method according to claim 1, further comprising: In case the complete configuration indicator is present in the RRC message, the configuration information of the SDAP layer and the NR PDCP layer configured for all bearers in the source BS is released.

3. The method according to claim 1, further comprising at least one of the following: Reset the Media Access Control (MAC) layer; Stop all running timers; Release the configured security configuration information; or Release the configuration information of the MAC layer or the radio link control (RLC) layer.

4. The method according to claim 1, wherein: The RRC message includes an RRC reconfiguration message or an RRC recovery message.

5. The method according to claim 1, further comprising: Identify successful completion of handover between different radio access technologies.

6. The method according to claim 1, wherein the source BS is NR, and the target BS is Evolved Universal Terrestrial Radio Access (E-UTRA).

7. The method according to claim 1, wherein the source BS is E-UTRA and the target BS is NR.

8. A user equipment (UE) in wireless communication for performing handover between different radio access technologies, the UE comprising: Transceiver; a memory storing one or more instructions; and At least one processor configured to execute the one or more instructions to: receiving a radio resource control (RRC) message; Identifying whether a complete configuration indicator is present in the RRC message; In the absence of a complete configuration indicator in the RRC message, configuration information of a Service Data Adaptation Protocol (SDAP) layer and a New Radio (NR) Packet Data Convergence Protocol (PDCP) layer configured in a source base station (BS) is not released; and Based on the identification that the complete configuration indicator is not present in the RRC message, the configuration information of the SDAP layer and the NR PDCP layer configured in the source BS is reused for the target BS.

9. The UE according to claim 8, wherein the at least one processor is further configured to: In case the complete configuration indicator is present in the RRC message, the configuration information of the SDAP layer and the NR PDCP layer configured for all bearers in the source BS is released.

10. The UE according to claim 8, wherein the at least one processor is further configured to: Reset the Media Access Control (MAC) layer; Stop all running timers; Release the configured security configuration information; or Release the configuration information of the MAC layer or the radio link control (RLC) layer.

11. The UE according to claim 8, wherein: The RRC message includes an RRC reconfiguration message or an RRC recovery message.

12. The UE according to claim 8, wherein the at least one processor is further configured to: Identify successful completion of handover between different radio access technologies.

13. The UE according to claim 8, wherein the source BS is a NR, and the target BS is an Evolved Universal Terrestrial Radio Access (E-UTRA).

14. The UE according to claim 8, wherein the source BS is E-UTRA, and the target BS is NR.

15. A method for performing a handover between different radio access technologies performed by a source base station (BS) in wireless communication, the method comprising: sending a radio resource control (RRC) message to a user equipment (UE), wherein a complete configuration indicator is present or absent in the RRC message, The complete configuration indicator is associated with whether the UE releases or does not release configuration information of a service data adaptation protocol (SDAP) layer and a new radio (NR) packet data convergence protocol (PDCP) layer configured in a source BS, and The complete configuration indicator is associated with whether the UE reuses the configuration information of the SDAP layer and the NR PDCP layer configured in the source BS for the target BS.

16. The method according to claim 15, wherein: The RRC message includes an RRC reconfiguration message or an RRC recovery message.

17. A source base station (BS) in wireless communication for performing a handover between different radio access technologies, the source BS comprising: Transceiver; a memory storing one or more instructions; and At least one processor configured to execute the one or more instructions to: sending a radio resource control (RRC) message to a user equipment (UE) with the full configuration indicator being present or absent in the RRC message, The complete configuration indicator is associated with whether the UE releases or does not release configuration information of a service data adaptation protocol (SDAP) layer and a new radio (NR) packet data convergence protocol (PDCP) layer configured in a source BS, and The complete configuration indicator is associated with whether the UE reuses the configuration information of the SDAP layer and the NR PDCP layer configured in the source BS for the target BS.

18. The source BS according to claim 17, wherein: The RRC message includes an RRC reconfiguration message or an RRC recovery message.

19. The source BS of claim 17, wherein the source BS is a NR, and the target BS is an Evolved Universal Terrestrial Radio Access (E-UTRA).

20. The source BS of claim 17, wherein the source BS is E-UTRA and the target BS is NR.

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