Method and apparatus for transmission and reception based on inter-carrier switching

Abstract

The present disclosure relates to a 5G or 6G communication system capable of achieving higher data transmission rates and maximizing frequency efficiency. Particularly, the present disclosure provides a method and apparatus for, when carrying out low-band carrier aggregation in a next-generation wireless communication system, maximizing utilization of low-band frequencies by allowing a terminal to alternately receive a plurality of downlink carriers.

Description

Transmission and reception method and device based on inter-carrier switching

[0001] The present disclosure relates to the operation of a terminal and a base station in a wireless communication system (or mobile communication system). Specifically, the present disclosure relates to a method for setting terminal capabilities according to a terminal structure to allow only one carrier to be received at a time by introducing a time difference between each carrier when a terminal receives a combination of multiple frequency bands or carriers within a band in a wireless communication system, as well as a method for setting a downlink suitable for the terminal capability when a base station that has received the terminal capability transmits the combination of carriers to the terminal, a method for setting the time and interval during which such variable switching operation is performed, and an apparatus capable of performing the same.

[0002] 5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in frequency bands below 6 GHz ('Sub 6 GHz'), such as 3.5 gigahertz (3.5 GHz), but also in ultra-high frequency bands called millimeter waves (mmWave), such as 28 GHz and 39 GHz ('Above 6 GHz'). In addition, for 6G mobile communication technology, which is referred to as a system beyond 5G communication, implementation in the terahertz band (e.g., the 3 terahertz (3 THz) band at 95 GHz) is being considered to achieve transmission speeds 50 times faster than 5G mobile communication technology and ultra-low latency reduced to one-tenth.

[0003] In the early stages of 5G mobile communication technology, aiming to support services and satisfy performance requirements for enhanced Mobile BroadBand (eMBB), Ultra Reliable & Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), technologies included beamforming and Massive MIMO to mitigate path loss and increase transmission distance in ultra-high frequency bands; dynamic operation of slot formats and numerology (such as the operation of multiple subcarrier spacing) for the efficient utilization of ultra-high frequency resources; initial access techniques to support multi-beam transmission and broadband; the definition and operation of Band-Width Parts (BWPs); new channel coding methods such as Low Density Parity Check (LDPC) codes for high-volume data transmission and Polar Codes for the reliable transmission of control information; L2 pre-processing; and technologies specialized for specific services. Standardization has been carried out for network slicing, which provides a dedicated network.

[0004] Currently, discussions are underway to improve and enhance the performance of the initial 5G mobile communication technology, taking into account the services that the 5G mobile communication technology was intended to support. Additionally, standardization of the physical layer is in progress for technologies such as V2X, which helps autonomous vehicles make driving decisions and enhances user convenience based on their own location and status information transmitted by the vehicle; NR-U (New Radio Unlicensed), which aims for system operation in unlicensed bands to comply with various regulatory requirements; NR terminal low power consumption technology (UE Power Saving); Non-Terrestrial Network (NTN), which is direct terminal-satellite communication for securing coverage in areas where communication with the terrestrial network is impossible; and positioning.

[0005] In addition, standardization is underway in the field of wireless interface architecture / protocols for technologies such as the Industrial Internet of Things (IIoT) to support new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) which provides nodes to expand network service areas by integrating wireless backhaul links and access links, Mobility Enhancement including Conditional Handover and Dual Active Protocol Stack (DAPS) Handover, and 2-step Random Access (2-step RACH for NR) which simplifies random access procedures. Standardization is also underway in the field of system architecture / services for 5G baseline architectures (e.g., Service based Architecture, Service based Interface) to incorporate Network Functions Virtualization (NFV) and Software Defined Network (SDN) technologies, and Mobile Edge Computing (MEC) which provides services based on the location of the terminal.

[0006] When such 5G mobile communication systems are commercialized, connected devices, which are increasing explosively, will be connected to communication networks. Accordingly, it is expected that there will be a need to enhance the functionality and performance of 5G mobile communication systems and to integrate the operation of connected devices. To this end, new research is planned to be conducted on 5G performance improvement and complexity reduction, AI service support, metaverse service support, and drone communication using eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support augmented reality and virtual reality.

[0007] Furthermore, the advancement of these 5G mobile communication systems encompasses multi-antenna transmission technologies such as new waveforms, Full Dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas to guarantee coverage in the terahertz band of 6G mobile communication technology; metamaterial-based lenses and antennas; high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM); and Reconfigurable Intelligent Surface (RIS) technology to improve terahertz band signal coverage; as well as Full Duplex technology for enhancing frequency efficiency and system networks in 6G mobile communication technology; AI-based communication technologies that realize system optimization by utilizing satellites and Artificial Intelligence (AI) from the design stage and internalizing end-to-end AI support functions; and the realization of services of complexity exceeding the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources. It could serve as a foundation for the development of next-generation distributed computing technologies.

[0008] Meanwhile, with the advancement of communication systems and the evolution of terminal receivers, research is being conducted on the process of receiving and processing multiple carriers transmitted via in-band discontinuous carrier coupling using a single terminal receiver, as well as on methods for setting terminal band parameters and frequency combination parameters to support this.

[0009] Various embodiments of the present disclosure aim to provide devices and methods capable of effectively providing services in a mobile communication system. Although there are no particular restrictions on the combination of frequency bands that constitute transmission and reception based on carrier coupling in a wireless communication system, from the perspective of implementing a product that actually supports carrier coupling, there is a possibility that transmission and reception using carrier coupling itself may be impossible, or that the performance of transmission and reception using carrier coupling may actually be inferior compared to transmission and reception using a single carrier, depending on signal distortion or the influence between multiple carriers due to the propagation characteristics of the frequency bands or carriers constituting the combination, or the design of a terminal that supports transmission and reception of multiple carriers. In cases where carrier coupling is practically impossible to implement or performance is inferior (for example, such a situation occurs in combinations of low frequencies below 1 GHz, where the diffraction of radio waves is high, resulting in good coverage characteristics, but the directivity is poor, making it disadvantageous from the perspective of interference control), it is difficult to resolve this in the current terminal design method, which must support most frequency bands with limited components and resources. Accordingly, various embodiments of the present disclosure aim to provide a method for setting terminal capabilities according to terminal structure, which enables a terminal to receive a specific carrier coupling with a time difference between each carrier when receiving the carrier coupling. In addition, various embodiments of the present disclosure aim to provide a method for setting the time and interval during which variable switching operations are performed, and a specific method for a base station to set carrier coupling transmission based thereon.

[0010] The technical problems to be solved in the various embodiments of the present disclosure are not limited to those mentioned above, and other unmentioned technical problems may be considered by those skilled in the art from the various embodiments of the present disclosure described below.

[0011] One embodiment of the present disclosure for solving the above-mentioned problems provides a method performed by a terminal in a wireless communication system. The method comprises the steps of: receiving a terminal capability enquiry message from a base station; and transmitting a terminal capability information message to the base station, based on the reception of the terminal capability enquiry message, the message including first information indicating support for LB-LB CA (carrier aggregation) based on switching of a first LB (low band) supporting FDD (frequency division duplex) and a second LB supporting SDL (supplementary downlink); wherein, based on the first information, in a first section where transmission or reception is performed in the FDD band of the first LB, reception is not performed in the SDL of the second LB, and in a second section where reception is performed in the SDL band of the second LB, transmission or reception is not performed in the FDD band of the first LB.

[0012] Additionally, one embodiment of the present disclosure provides a method performed by a base station in a wireless communication system. The method comprises the steps of: transmitting a terminal capability enquiry message to a terminal; and receiving a terminal capability information message from the terminal that includes first information indicating support for LB-LB CA (carrier aggregation) based on switching of a first LB (low band) supporting FDD (frequency division duplex) and a second LB supporting SDL (supplementary downlink), based on the transmission of the terminal capability enquiry message, wherein, based on the first information, in a first interval in which transmission or reception is performed in the FDD band of the first LB, reception is not performed in the SDL of the second LB, and in a second interval in which reception is performed in the SDL band of the second LB, transmission or reception is not performed in the FDD band of the first LB.

[0013] Additionally, one embodiment of the present disclosure provides a terminal of a wireless communication system. The terminal includes a memory for storing instructions; and a processing circuit connected to the memory and configured to transmit a terminal capability information message to the base station, wherein the terminal receives a terminal capability enquiry message from a base station based at least partially on the execution of the instructions, and based on the reception of the terminal capability enquiry message, the terminal includes first information indicating support for LB-LB CA (carrier aggregation) based on switching of a first LB (low band) supporting FDD (frequency division duplex) and a second LB supporting SDL (supplementary downlink), wherein based on the first information, in a first interval in which transmission or reception is performed in the FDD band of the first LB, reception is not performed in the SDL of the second LB, and in a second interval in which reception is performed in the SDL band of the second LB, transmission or reception is not performed in the FDD band of the first LB.

[0014] Additionally, one embodiment of the present disclosure provides a base station of a wireless communication system. The base station includes a memory for storing instructions; and a processing circuit connected to the memory and configured to receive from the terminal a UE capability information message, the base station including first information indicating support for LB-LB CA (carrier aggregation) based on switching of a first LB (low band) supporting FDD (frequency division duplex) and a second LB supporting SDL (supplementary downlink), based on the transmission of the UE capability enquiry message, at least partially based on the execution of the instructions. The base station includes a first information indicating support for LB-LB CA based on switching of a first LB supporting FDD (frequency division duplex) and a second LB supporting SDL (supplementary downlink), and based on the first information, in a first interval in which transmission or reception is performed in the FDD band of the first LB, reception is not performed in the SDL of the second LB, and in a second interval in which reception is performed in the SDL band of the second LB, transmission or reception is not performed in the FDD band of the first LB.

[0015] The various embodiments of the present disclosure described above are merely some of the preferred embodiments of the present disclosure, and various embodiments reflecting the technical features of the various embodiments of the present disclosure can be derived and understood by those skilled in the art based on the detailed description to be described below.

[0016] According to various embodiments of the present disclosure, devices and methods capable of effectively providing services in a mobile communication system can be provided.

[0017] According to various embodiments of the present disclosure, a method and apparatus for maximizing frequency efficiency can be provided, in which a base station and a terminal in a wireless communication system perform carrier coupling by fully utilizing available frequency bands regardless of frequency band combination.

[0018] The effects obtainable from the various embodiments of the present disclosure are not limited to those mentioned above, and other unmentioned effects can be clearly derived and understood by those skilled in the art based on the following detailed description.

[0019] FIG. 1 is a diagram illustrating the basic structure of the time-frequency domain in a wireless communication system according to one embodiment of the present disclosure.

[0020] FIG. 2 is a drawing illustrating a frame, subframe, and slot structure in a wireless communication system according to one embodiment of the present disclosure.

[0021] FIG. 3 is a drawing illustrating an example of a bandwidth portion setting in a wireless communication system according to an embodiment of the present disclosure.

[0022] FIG. 4 is a diagram illustrating an example of base station beam allocation according to the TCI (transmission configuration indicator) state setting in a wireless communication system according to one embodiment of the present disclosure.

[0023] FIG. 5 is a diagram illustrating the wireless protocol structure of a base station and a terminal in a single cell, carrier aggregation (CA), dual connectivity situation in a wireless communication system according to one embodiment of the present disclosure.

[0024] Figure 6 is a diagram illustrating an example of a duplexer and in-band interference in low-band carrier transmission and reception.

[0025] FIG. 7 is a diagram illustrating an example of inter-band interference between a duplexer and a diplexer in multiple low-band carrier transmission and reception.

[0026] FIG. 8 is a diagram illustrating an example of carrier coupling in which a base station and a terminal transmit and receive based on switching between carriers.

[0027] FIG. 9 is a diagram illustrating an example of carrier coupling in which a base station and a terminal transmit and receive based on switching between carriers.

[0028] FIG. 10 is a diagram illustrating an example of carrier coupling in which a base station and a terminal transmit and receive based on switching between carriers.

[0029] FIG. 11 is a diagram illustrating an example of carrier-switched transmission and reception between a base station and a terminal based on the terminal's capability report.

[0030] FIG. 12 is a diagram illustrating an example of the period during which a base station does not perform downlink transmission or the maximum period required for a terminal receiver change in a downlink switching-based carrier coupling.

[0031] FIG. 13 is a drawing illustrating the structure of a terminal in a wireless communication system according to one embodiment of the present disclosure.

[0032] FIG. 14 is a drawing illustrating the structure of a base station in a wireless communication system according to one embodiment of the present disclosure.

[0033] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0034] In describing the embodiments, technical details that are well known in the art to which this disclosure belongs and are not directly related to this disclosure are omitted. This is intended to convey the essence of this disclosure more clearly without obscuring it by omitting unnecessary explanations.

[0035] For the same reason, some components in the attached drawings have been exaggerated, omitted, or schematically depicted. Additionally, the dimensions of each component do not entirely reflect their actual dimensions. Identical or corresponding components in each drawing have been assigned the same reference numbers.

[0036] The advantages and features of the present disclosure, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components. Furthermore, in describing the present disclosure, if it is determined that a detailed description of a related function or configuration might unnecessarily obscure the essence of the present disclosure, such detailed description is omitted. Additionally, the terms described below are defined considering their functions in the present disclosure, and these may vary depending on the intentions or conventions of the user or operator. Therefore, their definitions should be based on the content throughout the specification.

[0037] At this point, it will be understood that each block of the process flow diagrams and combinations of the flow diagrams can be executed by computer program instructions. Since these computer program instructions can be loaded into the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, the instructions executed through the processor of the computer or other programmable data processing equipment create means to perform the functions described in the flow diagram block(s). Since these computer program instructions can also be stored in computer-available or computer-readable memory that can be directed toward the computer or other programmable data processing equipment to implement the function in a specific way, the instructions stored in computer-available or computer-readable memory can also produce a manufactured item containing instruction means to perform the function described in the flow diagram block(s). Since computer program instructions can be loaded onto a computer or other programmable data processing equipment, instructions that perform a series of operation steps on the computer or other programmable data processing equipment to create a process executed by the computer can also provide steps for executing the functions described in the flowchart block(s).

[0038] Additionally, each block may represent a module, segment, or part of code containing one or more executable instructions for executing a specific logical function(s). It should also be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For example, two blocks described in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order according to their corresponding functions.

[0039] In this embodiment, the term "part" refers to a software or hardware component such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit), and the "part" performs certain roles. However, the meaning of "part" is not limited to software or hardware. The "part" may be configured to reside in an addressable storage medium or configured to run one or more processors. Thus, as an example, the "part" includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and "parts" may be combined into a smaller number of components and "parts" or further separated into additional components and "parts." In addition, the components and 'parts' may be implemented to utilize one or more CPUs within the device or secure multimedia card. Also, in the embodiments, 'parts' may include one or more processors.

[0040] Wireless communication systems are evolving from providing early voice-oriented services to broadband wireless communication systems that provide high-speed, high-quality packet data services, such as communication standards like 3GPP’s HSPA (High Speed ​​Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2’s HRPD (High Rate Packet Data), UMB (Ultra Mobile Broadband), and IEEE’s 802.16e.

[0041] As a representative example of the above-mentioned broadband wireless communication system, the LTE system employs the Orthogonal Frequency Division Multiplexing (OFDM) method for the downlink (DL) and the Single Carrier Frequency Division Multiple Access (SC-FDMA) method for the uplink (UL). The uplink refers to a wireless link through which a terminal (User Equipment (UE) or Mobile Station (MS)) transmits data or control signals to a base station (eNode B, or base station (BS)), and the downlink refers to a wireless link through which a base station transmits data or control signals to a terminal. The above-mentioned multiple access method can distinguish the data or control information of each user by allocating and operating time-frequency resources to be sent for each user so that they do not overlap, that is, so that orthogonality is established.

[0042] As a future communication system following LTE, that is, a 5G communication system, it must be able to freely reflect the diverse requirements of users and service providers, and therefore, services that satisfy various requirements simultaneously must be supported. Services being considered for the 5G communication system include enhanced Mobile Broadband (eMBB), massive Machine Type Communication (mMTC), and Ultra Reliability Low Latency Communication (URLLC).

[0043] eMBB aims to provide data transmission speeds that are superior to those supported by existing LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, eMBB must be able to provide a peak data rate of 20 Gbps in the downlink and 10 Gbps in the uplink from the perspective of a single base station. Furthermore, while providing these peak data rates, the 5G communication system must also provide an increased user-perceived data rate. To satisfy these requirements, it necessitates improvements in various transmission and reception technologies, including enhanced Multi-Input Multi-Output (MIMO) transmission technology. Additionally, while LTE transmits signals using a maximum bandwidth of 20 MHz in the 2 GHz band, the 5G communication system can meet the data transmission speeds required by using a frequency bandwidth wider than 20 MHz in frequency bands of 3–6 GHz or above 6 GHz.

[0044] Simultaneously, mMTC is being considered to support application services such as the Internet of Things (IoT) in 5G communication systems. To efficiently provide IoT, mMTC requires support for a large number of terminal connections within a cell, improved terminal coverage, enhanced battery life, and reduced terminal costs. Since IoT devices are attached to various sensors and equipment to provide communication functions, the system must be able to support a large number of terminals within a cell (e.g., 1,000,000 terminals / km²). Furthermore, due to the nature of the service, terminals supporting mMTC are likely to be located in dead zones not covered by cells, such as building basements; therefore, they may require wider coverage compared to other services provided by 5G communication systems. Terminals supporting mMTC must consist of low-cost devices, and since it is difficult to frequently replace terminal batteries, a very long battery life of 10 to 15 years may be required.

[0045] Finally, URLLC is a mission-critical cellular-based wireless communication service. Examples include services used for remote control of robots or machinery, industrial automation, unmanned aerial vehicles, remote health care, and emergency alerts. Therefore, the communication provided by URLLC must offer very low latency and very high reliability. For instance, services supporting URLLC must satisfy an air interface latency of less than 0.5 milliseconds and simultaneously require a packet error rate of 10⁻⁵ or less. Consequently, for services supporting URLLC, 5G systems must provide a smaller Transmit Time Interval (TTI) than other services, and design considerations may be required to allocate wide resources within the frequency band to ensure the reliability of the communication link.

[0046] The three 5G services, namely eMBB, URLLC, and mMTC, can be multiplexed and transmitted within a single system. In this case, different transmission and reception techniques and parameters may be used between the services to satisfy the different requirements of each service. Of course, 5G is not limited to the three services mentioned above.

[0047] Hereinafter, a base station is an entity that performs resource allocation for terminals and may be at least one of a gNode B, eNode B, Node B, BS (Base Station), wireless access unit, base station controller, or a node on a network. A terminal may include a UE (User Equipment), MS (Mobile Station), cellular phone, smartphone, computer, or a multimedia system capable of performing communication functions. In this disclosure, a downlink (DL) refers to a wireless transmission path of a signal transmitted by a base station to a terminal, and an uplink (UL) refers to a wireless transmission path of a signal transmitted by a terminal to a base station. Furthermore, while LTE or LTE-A systems may be described as examples below, embodiments of this disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, 5th generation mobile communication technologies (5G, new radio, NR) developed after LTE-A may be included therein, and the 5G below may be a concept that includes existing LTE, LTE-A, and other similar services. In addition, the present disclosure may be applied to other communication systems with some modifications made at the discretion of a person with skilled technical knowledge, without significantly departing from the scope of the present disclosure.

[0048] Hereinafter, a / b may be understood as at least one of a or b.

[0049] [NR Time-Frequency Resources]

[0050] The frame structure of the 5G system will be explained in more detail below with reference to the drawings.

[0051] Figure 1 is a diagram illustrating the basic structure of the time-frequency domain, which is a wireless resource domain where data or control channels are transmitted in a 5G system.

[0052] The horizontal axis of FIG. 1 represents the time domain, and the vertical axis represents the frequency domain. In the time and frequency domains, the basic unit of a resource is a resource element (RE, 101), which can be defined as one OFDM symbol (102) on the time axis and one subcarrier (103) on the frequency axis. In the frequency domain (For example, 12) consecutive REs can form a resource block (RB, 104). In the time axis, a subframe (110) can contain multiple OFDM symbols (102). For example, the length of one subframe can be 1 ms.

[0053] FIG. 2 is a drawing illustrating a frame, subframe, and slot structure in a wireless communication system according to one embodiment of the present disclosure.

[0054] FIG. 2 illustrates an example of a frame (200), subframe (201), and slot (202) structure. One frame (200) can be defined as 10ms. One subframe (201) can be defined as 1ms, and thus one frame (200) can be composed of a total of 10 subframes (201). One slot (202, 203) can be defined as 14 OFDM symbols (i.e., the number of symbols per slot ( =14). One subframe (201) may be composed of one or more slots (202, 203), and the number of slots (202, 203) per one subframe (201) is a set value for the subcarrier interval. It may vary depending on (204, 205). In one example of FIG. 2, the subcarrier interval setting value The case where =0(204) and The case where =1(205) is illustrated. If =0 (204), 1 subframe (201) can be composed of 1 slot (202), and If =1 (205), 1 subframe (201) can be composed of 2 slots (203). That is, the setting value for the subcarrier interval Number of slots per subframe according to ( ) may vary, and accordingly, the number of slots per frame ( ) may vary. Setting the interval for each subcarrier According to and It can be defined by the following [Table 1].

[0055] 0141011142022144043148084141601651432032

[0056] [Bandwidth Section (BWP)]

[0057] Next, the bandwidth part (BWP) setting in a 5G communication system will be explained in detail with reference to the drawing.

[0058] FIG. 3 is a drawing illustrating an example of a bandwidth portion setting in a wireless communication system according to one embodiment of the present disclosure.

[0059] FIG. 3 shows an example in which the terminal bandwidth (UE bandwidth) (300) is configured into two bandwidth portions, namely bandwidth portion #1 (BWP#1) (301) and bandwidth portion #2 (BWP#2) (302). The base station may configure one or more bandwidth portions for the terminal and may configure the following information for each bandwidth portion.

[0060] BWP ::= SEQUENCE {bwp-Id BWP-Id,locationAndBandwidth INTEGER (1..65536),subcarrierSpacing ENUMERATED {n0, n1, n2, n3, n4, n5},cyclicPrefix ENUMERATED { extended}}

[0061] Of course, the above examples are not limited, and various parameters related to bandwidth portions may be configured for the terminal in addition to the above configuration information. The above information may be transmitted by the base station to the terminal via higher-layer signaling, for example, radio resource control (RRC) signaling. At least one of the configured bandwidth portions may be activated. Whether a configured bandwidth portion is activated may be transmitted semi-statically from the base station to the terminal via RRC signaling or dynamically via downlink control information (DCI).

[0062] According to some embodiments, prior to the RRC connection, the terminal may receive an initial bandwidth portion (initial BWP) for initial connection from the base station via a master information block (MIB). More specifically, during the initial connection phase, the terminal may receive configuration information for a control resource set (CORESET) and a search space via the MIB, through which a physical downlink control channel (PDCCH) can be transmitted to receive system information required for initial connection (which may correspond to remaining system information (RMSI) or system information block 1 (SIB1)). The control area and search space configured via the MIB may each be considered as Identity (ID) 0. The base station may notify the terminal via the MIB of configuration information, such as frequency allocation information, time allocation information, and numerology, for control area #0. In addition, the base station may notify the terminal via the MIB of configuration information regarding the monitoring period and monitoring occasion for control area #0, i.e., configuration information for search area #0. The terminal may regard the frequency area set as control area #0 obtained from the MIB as the initial bandwidth portion for initial access. In this case, the identifier (ID) of the initial bandwidth portion may be regarded as 0.

[0063] The settings for the bandwidth portion supported by the above 5G can be used for various purposes.

[0064] According to some embodiments, if the bandwidth supported by the terminal is smaller than the system bandwidth, this can be supported through the bandwidth portion setting. For example, by setting the frequency position of the bandwidth portion (setting information 2) to the terminal, the terminal can transmit and receive data at a specific frequency position within the system bandwidth.

[0065] Additionally, according to some embodiments, a base station may set multiple bandwidth portions for a terminal for the purpose of supporting different numerologies. For example, to support data transmission and reception using both a 15 kHz subcarrier interval and a 30 kHz subcarrier interval for a terminal, two bandwidth portions may be set to subcarrier intervals of 15 kHz and 30 kHz, respectively. Different bandwidth portions may be frequency division multiplexed (FDM), and when data transmission and reception is to be performed with a specific subcarrier interval, the bandwidth portion set to that subcarrier interval may be activated.

[0066] In addition, according to some embodiments, a base station may set a bandwidth portion having different bandwidth sizes for the purpose of reducing the power consumption of the terminal. For example, if the terminal supports a very large bandwidth, such as 100 MHz, and always transmits and receives data using that bandwidth, very large power consumption may occur. In particular, in a situation where there is no traffic, performing monitoring of an unnecessary downlink control channel using a large bandwidth of 100 MHz can be very inefficient in terms of power consumption. To reduce the power consumption of the terminal, the base station may set a bandwidth portion of a relatively small bandwidth, such as 20 MHz, for the terminal. In a situation where there is no traffic, the terminal can perform monitoring operations in the 20 MHz bandwidth portion, and when data is generated, it can transmit and receive data using the 100 MHz bandwidth portion according to the instructions of the base station.

[0067] In the method for configuring the above bandwidth portion, terminals prior to RRC connection can receive configuration information for the initial bandwidth portion (initial BWP) through the MIB during the initial connection phase. More specifically, the terminal can receive a configuration of a control area (i.e., CORESET) for a downlink control channel through which a DCI scheduling a SIB (system information block) can be transmitted from the MIB of the PBCH (physical broadcast channel). The bandwidth of the control area configured by the MIB can be considered as the initial bandwidth portion, and through the configured initial bandwidth portion, the terminal can receive the PDSCH (physical downlink shared channel) through which the SIB is transmitted. In addition to the purpose of receiving the SIB, the initial bandwidth portion may also be utilized for other system information (OSI), paging, and random access.

[0068] [Bandwidth Section (BWP) Change]

[0069] When one or more bandwidth parts are set for a terminal, the base station may instruct the terminal to change (or switch, transition) the bandwidth part using the bandwidth part indicator field in the DCI. For example, in FIG. 3, if the currently active bandwidth part of the terminal is bandwidth part #1 (301), the base station may instruct the terminal to bandwidth part #2 (302) using the bandwidth part indicator in the DCI, and the terminal may perform a bandwidth part change to bandwidth part #2 (302) indicated by the received bandwidth part indicator in the DCI.

[0070] As mentioned above, since DCI-based bandwidth portion changes can be directed by a DCI scheduling a PDSCH or PUSCH (physical uplink shared channel), when a terminal receives a bandwidth portion change request, it must be able to receive or transmit the PDSCH or PUSCH scheduled by the corresponding DCI without difficulty in the changed bandwidth portion. To this end, the standard specifies requirements for the required delay time (TBWP) for bandwidth portion changes, which can be defined, for example, as shown in Table 3 below.

[0071] NR Slot length (ms)BWP switch delay T BWP (slots)Type 1 Note 1 Type 2 Note 1 011310.52520.253930.125618Note 1: Depends on UE capability.Note 2: If the BWP switch involves changing of SCS, the BWP switch delay is determined by the larger one between the SCS before BWP switch and the SCS after BWP switch.

[0072] The requirements for bandwidth portion change delay time support Type 1 or Type 2 depending on the terminal's capability. The terminal can report the supported bandwidth portion delay time type to the base station.

[0073] In accordance with the aforementioned requirements for the bandwidth change delay time, when a terminal receives a DCI containing a bandwidth change indicator in slot n, the terminal can complete the change to the new bandwidth portion indicated by the bandwidth change indicator at a time not later than slot n + TBWP, and can perform transmission and reception for the data channel scheduled by the corresponding DCI in the changed new bandwidth portion. When the base station intends to schedule a data channel to the new bandwidth portion, it may determine the time domain resource allocation for the data channel by considering the terminal's bandwidth change delay time (TBWP). That is, when the base station schedules a data channel to the new bandwidth portion, in the method of determining the time domain resource allocation for the data channel, it may schedule the data channel after the bandwidth change delay time. Accordingly, the terminal may not expect the DCI indicating the bandwidth change to indicate a slot offset (K0 or K2) value smaller than the bandwidth change delay time (TBWP).

[0074] If a terminal receives a DCI (e.g., DCI format 1_1 or 0_1) instructing a change in the bandwidth portion, the terminal may not perform any transmission or reception during a time interval corresponding to the time interval from the third symbol of the slot in which the PDCCH containing the said DCI was received to the beginning of the slot indicated by the slot offset value (K0 or K2) indicated by the time domain resource allocation indicator field within the said DCI. For example, if a terminal receives a DCI instructing a change in the bandwidth portion in slot n, and the slot offset value indicated by the said DCI is K, the terminal may not perform any transmission or reception from the third symbol of slot n to the symbol before slot n+K (i.e., the last symbol of slot n+K-1).

[0075] [QCL (quasi-colocation), TCI state]

[0076] In a wireless communication system, one or more different antenna ports (or may be replaced by one or more channels, signals, and combinations thereof, but for convenience in the following description of the disclosure, they will be referred to collectively as different antenna ports) may be associated with each other by a quasi-co-location (QCL) setting as shown in [Table 4] below. The TCI state is intended to disclose the QCL relationship between a PDCCH (or PDCCH DMRS (demodulation reference signal)) and another RS ​​or channel. When a reference antenna port A (reference RS #A) and another target antenna port B (target RS #B) are said to be QCLed with each other, it means that the terminal is permitted to apply some or all of the large-scale channel parameters estimated at the antenna port A to the channel measurement from the antenna port B. QCL may require associating different parameters depending on the situation, such as 1) time tracking affected by average delay and delay spread, 2) frequency tracking affected by Doppler shift and Doppler spread, 3) radio resource management (RRM) affected by average gain, and 4) beam management (BM) affected by spatial parameters. Accordingly, NR supports four types of QCL relationships as shown in [Table 4] below.

[0077] QCL typeLarge-scale characteristicsADoppler shift, Doppler spread, average delay, delay spreadBDoppler shift, Doppler spreadCDoppler shift, average delayDSpatial Rx parameter

[0078] The above spatial RX parameter may collectively refer to some or all of various parameters, such as Angle of arrival (AoA), Power Angular Spectrum (PAS) of AoA, Angle of departure (AoD), PAS of AoD, transmit / receive channel correlation, transmit / receive beamforming, and spatial channel correlation.

[0079] The above QCL relationship can be configured for the terminal through the RRC parameters TCI-State and QCL-Info as shown in Table 5 below. Referring to [Table 5], the base station can configure one or more TCI states for the terminal and provide up to two QCL relationships (qcl-Type1, qcl-Type2) for the RS that references the ID of the said TCI state, i.e., the target RS. At this time, each QCL information (QCL-Info) included in each said TCI state includes the serving cell index and BWP index of the reference RS pointed to by the corresponding QCL information, the type and ID of the reference RS, and the QCL type as shown in [Table 4] above.

[0080] TCI-State ::= SEQUENCE {tci-StateId TCI-StateId,(ID of the corresponding TCI state)qcl-Type1 QCL-Info,(QCL information of the first reference RS of the RS (target RS) referencing the corresponding TCI state ID)qcl-Type2 QCL-Info OPTIONAL, -- Need R(QCL information of the second reference RS of the RS (target RS) referencing the corresponding TCI state ID)...}QCL-Info ::= SEQUENCE {cell ServCellIndex OPTIONAL, -- Need R(serving cell index of the reference RS pointed to by the corresponding QCL information)bwp-Id BWP-Id OPTIONAL, -- Cond CSI-RS-Indicated(BWP index of the reference RS pointed to by the corresponding QCL information)referenceSignal CHOICE {csi-rs NZP-CSI-RS-ResourceId,ssb SSB-Index(of the CSI-RS ID or SSB ID pointed to by the corresponding QCL information one)},qcl-Type ENUMERATED {typeA, typeB, typeC, typeD},...}

[0081] Figure 4 is a diagram illustrating an example of base station beam allocation according to TCI state settings.

[0082] Referring to FIG. 4, the base station can transmit information about N different beams to the terminal through N different TCI states. For example, as shown in FIG. 4, when N=3, the base station can notify that the antenna ports referencing the different TCI states 400, 405, or 410 are associated with different spatial Rx parameters, i.e., different beams, by setting the qcl-Type2 parameters included in the three TCI states (400, 405, 410) to be associated with the CSI-RS (channel state information - reference signal) or SSB (synchronization signal block) corresponding to the different beams and set to QCL type D.

[0083] Tables 6 through 10 below show valid TCI state settings according to the target antenna port type.

[0084] [Table 6] shows the valid TCI state settings when the target antenna port is CSI-RS for tracking (i.e., TRS). The aforementioned TRS refers to an NZP (non-zero power) CSI-RS where the repetition parameter is not set and trs-Info is set to true. Setting 3 in Table 10 can be used for aperiodic TRS. (Table 6: Valid TCI state settings when the target antenna port is CSI-RS for tracking (TRS))

[0085] Valid TCI state configurationDL RS 1qcl-Type1DL RS 2(if configured)qcl-Type2(if-configured)1SSBQCL-TypeCSSBQCL-TypeD2SSBQCL-TypeCCSI-RS (BM)QCL-TypeD3TRS (periodic)QCL-TypeATRS (same as DL RS 1)QCL-TypeD

[0086] [Table 7] shows the valid TCI state settings when the target antenna port is CSI-RS for CSI. The above CSI-RS for CSI refers to an NZP CSI-RS where the parameter indicating repetition (e.g., the repetition parameter) is not set and trs-Info is not set to true. (Table 7: Valid TCI state settings when the target antenna port is CSI-RS for CSI)

[0087] Valid TCI state configurationDL RS 1qcl-Type1DL RS 2(if configured)qcl-Type2(if-configured)1TRSQCL-TypeASSBQCL-TypeD2TRSQCL-TypeACSI-RS (BM)QCL-TypeD3TRSQCL-TypeATRS (same as DL RS 1)QCL-TypeD4TRSQCL-TypeB

[0088] [Table 8] shows the valid TCI state settings when the target antenna port is CSI-RS for beam management (BM, synonymous with CSI-RS for L1 RSRP reporting). The above CSI-RS for BM refers to an NZP CSI-RS where the repetition parameter is set to either On or Off and trs-Info is not set to true. (Table 8: Valid TCI state settings when the target antenna port is CSI-RS for BM (for L1 RSRP reporting))

[0089] Valid TCI state configurationDL RS 1qcl-Type1DL RS 2(if configured)qcl-Type2(if-configured)1TRSQCL-TypeATRS (same as DL RS 1)QCL-TypeD2TRSQCL-TypeACSI-RS (BM)QCL-TypeD3SS / PBCH BlockQCL-TypeCSS / PBCH BlockQCL-TypeD

[0090] [Table 9] shows the valid TCI state settings when the target antenna port is PDCCH DMRS. (Table 9: Valid TCI state settings when the target antenna port is PDCCH DMRS)

[0091] Valid TCI state configurationDL RS 1qcl-Type1DL RS 2(if configured)qcl-Type2(if-configured)1TRSQCL-TypeATRS (same as DL RS 1)QCL-TypeD2TRSQCL-TypeACSI-RS (BM)QCL-TypeD3CSI-RS (CSI)QCL-TypeCCSI-RS (same as DL RS 1)QCL-TypeD

[0092] [Table 10] shows the valid TCI state settings when the target antenna port is PDSCH DMRS. (Table 10: Valid TCI state settings when the target antenna port is PDSCH DMRS)

[0093] Valid TCI state configurationDL RS 1qcl-Type1DL RS 2(if configured)qcl-Type2(if-configured)1TRSQCL-TypeATRSQCL-TypeD2TRSQCL-TypeACSI-RS (BM)QCL-TypeD3CSI-RS (CSI)QCL-TypeCCSI-RS (CSI)QCL-TypeD

[0094] The representative QCL setting method according to [Table 6] to [Table 10] above is to operate by setting the target antenna port and reference antenna port for each stage as "SSB" -> "TRS" -> "CSI-RS for CSI, or CSI-RS for BM, or PDCCH DMRS, or PDSCH DMRS". Through this, it is possible to link the statistical characteristics measurable from the SSB and TRS to each antenna port to assist the reception operation of the terminal.

[0095] [CA / DC Related]

[0096] FIG. 5 is a diagram illustrating the wireless protocol structure of a base station and a terminal in a single cell, carrier aggregation (CA), and dual connectivity (DC) situation according to one embodiment of the present disclosure.

[0097] Referring to Fig. 5, the wireless protocol of the next-generation mobile communication system consists of NR SDAP (service data adaptation protocol, 525, 570), NR PDCP (packet data convergence protocol, 530, 565), NR RLC (radio link control, 535, 560), and NR MAC (medium access control, 540, 555) at the terminal and the NR base station, respectively.

[0098] The main functions of NR SDAP (525, 570) may include some of the following functions.

[0099] - User data transfer function (transfer of user plane data)

[0100] - Mapping function between a QoS (quality of service) flow and a data bearer for uplink and downlink (mapping between a QoS flow and a DRB for both DL and UL)

[0101] - Marking QoS flow ID for uplink and downlink (marking QoS flow ID in both DL and UL packets)

[0102] - Function to map reflective QoS flow to the data bearer for uplink SDAP PDUs (protocol data units).

[0103] Regarding the SDAP layer device, the terminal may receive a setting via an RRC message indicating whether to use the header of the SDAP layer device or the functions of the SDAP layer device for each PDCP layer device, for each bearer, or for each logical channel. If the SDAP header is set, the terminal may be instructed to update or reset the mapping information for the uplink and downlink QoS flows and data bearers to the NAS (non-access stratum) QoS reflection setting 1-bit indicator (NAS reflective QoS) and the AS QoS reflection setting 1-bit indicator (AS reflective QoS) of the SDAP header. The SDAP header may include QoS flow ID information indicating QoS. The QoS information may be used for data processing priority, scheduling information, etc., to support smooth service.

[0104] The main functions of NR PDCP (530, 565) may include some of the following functions.

[0105] - Header compression and decompression features (ROHC only)

[0106] - User data transfer function (Transfer of user data)

[0107] - Sequential delivery function (In-sequence delivery of upper layer PDUs)

[0108] - Out-of-sequence delivery of upper layer PDUs

[0109] - Reordering function (PDCP PDU reordering for reception)

[0110] - Duplicate detection function (Duplicate detection of lower layer SDUs)

[0111] - Retransmission of PDCP SDUs

[0112] - Encryption and decryption functions (Ciphering and deciphering)

[0113] - Timer-based SDU (service data unit) discard function (Timer-based SDU discard in uplink.)

[0114] In the above, the reordering function of the NR PDCP device refers to a function that reorders PDCP PDUs received from a lower layer in order based on the PDCP SN (sequence number), and may include a function that transmits data to an upper layer in the reordered order. Alternatively, the reordering function of the NR PDCP device may include a function that transmits immediately without considering the order, a function that records lost PDCP PDUs by reordering, a function that reports the status of lost PDCP PDUs to the transmitting side, and a function that requests retransmission of lost PDCP PDUs.

[0115] The main functions of NR RLC (535, 560) may include some of the following functions.

[0116] - Data transfer function (Transfer of upper layer PDUs)

[0117] - Sequential delivery function (In-sequence delivery of upper layer PDUs)

[0118] - Out-of-sequence delivery of upper layer PDUs

[0119] - ARQ (automatic repeat request) function (Error Correction through ARQ)

[0120] - Concatenation, segmentation, and reassembly functions of RLC SDUs

[0121] - Re-segmentation function (Re-segmentation of RLC data PDUs)

[0122] - Reordering function (Reordering of RLC data PDUs)

[0123] - Duplicate detection

[0124] - Error detection function (Protocol error detection)

[0125] - RLC SDU discard function

[0126] RLC re-establishment function

[0127] In the above, the in-sequence delivery function of the NR RLC device refers to the function of delivering RLC SDUs received from a lower layer to an upper layer in order. The in-sequence delivery function of the NR RLC device may include a function of reassembling and delivering the RLC SDUs when the original RLC SDU is received divided into multiple RLC SDUs, a function of rearranging the received RLC PDUs based on an RLC SN (sequence number) or PDCP SN, a function of recording lost RLC PDUs by rearranging the order, a function of reporting the status of lost RLC PDUs to the transmitting side, and a function of requesting retransmission of lost RLC PDUs. The in-sequence delivery function of the NR RLC device may include a function to deliver only the RLC SDUs prior to the lost RLC SDU in order to the upper layer if there is a lost RLC SDU, or a function to deliver all RLC SDUs received before the timer started in order to the upper layer if a predetermined timer has expired even if there is a lost RLC SDU. Alternatively, the in-sequence delivery function of the NR RLC device may include a function to deliver all RLC SDUs received up to the present in order to the upper layer if a predetermined timer has expired even if there is a lost RLC SDU.In addition, the RLC PDUs described above may be processed in the order in which they are received (regardless of the sequence number order, in the order of arrival) and delivered to the PDCP device out of order (out-of-sequence delivery). In the case of segments, segments stored in a buffer or to be received later may be received, reconstructed into a single complete RLC PDU, processed, and delivered to the PDCP device. The NR RLC layer may not include a concatenation function, and this function may be performed by the NR MAC layer or replaced by the multiplexing function of the NR MAC layer.

[0128] In the above, the out-of-sequence delivery function of the NR RLC device refers to a function of delivering RLC SDUs received from a lower layer directly to an upper layer regardless of order. It may include a function of reassembling and delivering RLC SDUs when a single RLC SDU is received divided into multiple RLC SDUs, and may include a function of storing the RLC SN or PDCP SN of the received RLC PDUs and sorting the order to record the lost RLC PDUs.

[0129] The NR MAC (540, 555) can be connected to multiple NR RLC layer devices configured in a terminal, and the main functions of the NR MAC may include some of the following functions.

[0130] - Mapping function (Mapping between logical channels and transport channels)

[0131] - Multiplexing and demultiplexing functions (Multiplexing / demultiplexing of MAC SDUs)

[0132] - Scheduling information reporting function

[0133] - HARQ function (Error correction through HARQ)

[0134] - Priority handling between logical channels of one UE

[0135] - Priority handling between UEs by means of dynamic scheduling

[0136] - MBMS service identification function

[0137] - Transport format selection function

[0138] - Padding

[0139] The NR PHY layer (545, 550) can perform the operation of channel coding and modulating upper layer data, creating OFDM symbols and transmitting them to the wireless channel, or demodulating OFDM symbols received through the wireless channel and channel decoding them to transmit them to the upper layer.

[0140] The detailed structure of the above wireless protocol structure may vary depending on the carrier (or cell) operation method. For example, when a base station transmits data to a terminal based on a single carrier (or cell), the base station and the terminal use a protocol structure that has a single structure for each layer, such as 500. On the other hand, when a base station transmits data to a terminal based on Carrier Aggregation (CA) using multiple carriers in a single TRP, the base station and the terminal use a protocol structure that has a single structure up to the RLC, such as 510, but multiplexes the PHY layer through the MAC layer. As another example, when a base station transmits data to a terminal based on Dual Connectivity (DC) using multiple carriers in multiple TRPs, the base station and the terminal use a protocol structure that has a single structure up to the RLC, such as 520, but multiplexes the PHY layer through the MAC layer.

[0141] [Regarding Terminal Capability Reporting]

[0142] In LTE and NR, a terminal can perform a procedure to report the capabilities supported by the terminal to the base station while connected to the serving base station. In the description below, this is referred to as a UE capability report.

[0143] A base station may transmit a UE capability enquiry message requesting capability reporting to a connected terminal. The message may include a request for a UE capability specific to the base station's RAT (radio access technology) type. The request for a UE capability specific to the RAT type may include information such as the frequency band combinations supported by the terminal. Additionally, regarding the UE capability enquiry message, multiple UE capabilities for each RAT type may be requested at once through a single RRC message container transmitted by the base station, or the base station may transmit the UE capability enquiry message, which includes the request for a UE capability for each RAT type, to the terminal multiple times. That is, the base station may transmit the UE capability enquiry to the terminal multiple times using a single message, and the terminal may construct a corresponding UE capability information message and report it to the base station multiple times. In next-generation mobile communication systems, a UE capability request can be made for NR, LTE, EN-DC (E-UTRA - NR dual connectivity), and MR-DC (Multi-RAT dual connectivity). In addition, the above terminal capability inquiry message is generally transmitted initially after the terminal is connected to the base station, but the base station may request it under any conditions when necessary.

[0144] In the above step, the terminal that receives a request for a UE capability report from the base station configures the terminal capability according to the RAT type and band information requested from the base station. The method by which the terminal configures the UE capability in the NR system is summarized below.

[0145] 1. If the terminal receives a list of LTE and / or NR bands from the base station via a UE capability request, the terminal configures a band combination (BC) for EN-DC and NR stand-alone (SA). That is, it constructs a candidate list of BCs for EN-DC and NR SA based on the bands requested from the base station via FreqBandList. Additionally, the bands have priority in the order listed in FreqBandList.

[0146] 2. If the base station requests a UE capability report by setting the “eutra-nr-only” flag or the “eutra” flag, the terminal completely removes NR SA BCs from the above-mentioned list of configured BC candidates. This operation may occur only when the LTE base station (eNB) requests the “eutra” capability.

[0147] 3. Subsequently, the terminal removes fallback BCs from the candidate list of BCs configured in the above step. Here, a fallback BC refers to a BC that can be obtained by removing a band corresponding to at least one SCell from any BC; this step can be omitted because the BC before removing the band corresponding to at least one SCell already covers the fallback BC. This step applies to MR-DC as well, that is, it applies to LTE bands. The BCs remaining after this step constitute the final "candidate BC list."

[0148] 4. The terminal selects BCs from the above final "candidate BC list" that match the RAT type requested by the base station, i.e., BCs to be reported. In this step, the terminal constructs the supportedBandCombinationList in a predetermined order. That is, the terminal constructs the BCs to be reported and the UE capabilities according to the pre-set order of rat-Type (nr -> eutra-nr -> eutra). Additionally, it constructs a featureSetCombination for the constructed supportedBandCombinationList and constructs a list of "candidate feature set combinations" from the candidate BC list from which the list of fallback BCs (containing capabilities of the same or lower level) has been removed. The above "candidate feature set combinations" include feature set combinations for both NR and EUTRA-NR BCs and can be obtained from the feature set combinations of the UE-NR-Capabilities and UE-MRDC-Capabilities containers.

[0149] 5. Additionally, if the requested rat Type is eutra-nr and has an influence, featureSetCombinations is included in both the UE-MRDC-Capabilities and UE-NR-Capabilities containers. However, the NR feature set is included only in UE-NR-Capabilities.

[0150] After terminal capability is configured, the terminal transmits a terminal capability information message containing the terminal capability to the base station. Based on the terminal capability received from the terminal, the base station performs appropriate scheduling and transmission / reception management for the corresponding terminal.

[0151] <1st Embodiment: Switching-based DL CA Scenario>

[0152] [Motivation]

[0153] In terms of maximum coverage of base stations or terminals, the low-band at 1 GHz or lower has superior radio wave characteristics compared to the mid-band between 1-3 GHz or the high-band at 3 GHz or higher. Therefore, it has been usefully utilized in regions where base station installation is difficult or where population density is low (regions with such characteristics may be defined as the first region in the embodiments of the present disclosure), but there is a problem in that the directivity of the radio waves or the transmittable bandwidth may be relatively small. On the other hand, the mid-band and high-band have more advantages in terms of data transmission rate or capacity, even though their maximum coverage is not as great as that of the low-band. Thus, they are useful bands in urban areas with high radio wave usage or high population density (regions with such characteristics may be defined as the second region in the embodiments of the present disclosure), despite having poor radio wave coverage compared to the low-band. Based on these band-specific propagation characteristics, recent network designs generally focus on mid-band or high-band in urban areas and low-band in rural areas, and this assumption is actually applied in establishing frequency strategies and designing mobile communication cells. However, one of the problems observed in this structure is that when actual users move from rural areas to urban areas or vice versa, they frequently remain in the low-band rather than the mid-band or high-band for data / voice communication. In this case, users cannot avoid experiencing the low data transmission rate compared to the mid-band or high-band, which was previously pointed out as a problem with the low-band.

[0154] In this case, carrier aggregation (CA) technology can be considered as one way to compensate for low data transmission rates. Carrier aggregation is a technology that combines two or more carriers to improve the efficient use of frequency and maximum transmission rates. While numerous frequency combinations supporting carrier aggregation technology have been defined up to the current 5G, from the perspective of implementing products that actually support carrier aggregation, there is a possibility that transmission and reception using carrier aggregation itself may be impossible or that performance may actually be lower compared to transmission and reception using a single carrier, depending on signal distortion caused by the frequency bands or propagation characteristics of the carriers constituting the combination, the influence between multiple carriers, or the design of terminals that support transmission and reception of multiple carriers.

[0155] Cases where such carrier coupling is impractical to implement or performs poorly occur particularly in combinations between low-band frequencies below 1 GHz, where the high diffraction of radio waves results in good coverage but poor directivity, making it disadvantageous from the perspective of interference control. Although this has been supported in wireless access standards since the early days of carrier coupling technology, just like other carrier couplings, it remains difficult to support from the perspective of terminal hardware, which must be designed considering actual radio wave characteristics. Furthermore, given the current terminal design approach that must support most frequency bands with limited components and resources, it is not easy to resolve these radio wave characteristic issues. Given the current terminal hardware implementation that must support most mobile communication bands within a limited space, it may be difficult to achieve better performance through low-band carrier coupling compared to general single-carrier transmission for the following reasons. First, as shown in FIG. 6, from the perspective of a duplexer (603) that distinguishes the uplink (601) and downlink (602) in terminal hardware, the low band of 1 GHz or less is generally transmitted by distinguishing the uplink and downlink using a frequency division multiplex (FDD). Compared to the radio wave characteristics of the low band, the frequency separation (604) between the uplink band and the downlink band within the same band is not large, and the duplexer designed to distinguish them cannot be precisely designed considering the fractional bandwidth due to the radio wave characteristics of the low band, so the signal transmitted by the terminal to the uplink may cause interference (605) in the downlink band. Furthermore, as shown in FIG. 7, in a low-band carrier coupling that simultaneously transmits and receives multiple low-band carriers (701, 702), not only the aforementioned problems but also cases where interference (703, 704) to adjacent bands occurs must be taken into account, so it may be virtually impossible for a terminal to support low-band carrier coupling.To address the propagation characteristics issues of such low-band carrier coupling, one could consider minimizing inter-band interference through band-independent antenna and hardware designs; however, this approach requires additional costs, hardware, and space at the terminal, which can lead to hardware complexity. Such constraints on terminal implementation hinder the simultaneous utilization of multiple low-bands and act as an impediment to fully utilizing data transmission rates and capacity in regions with high low-band usage.

[0156] As one method to increase the utilization of multiple low bands and enhance efficiency, a method of transmitting and receiving by switching low band carrier coupling to crossover between downlink carriers may be considered. When transmitting and receiving by crossing with a time difference in this manner, factors that impede carrier coupling performance by simultaneously transmitting and receiving the existing low band carrier coupling can be eliminated. In the following embodiments, various scenarios in which a terminal transmits and receives by switching low band carrier coupling by band or carrier are described in detail. In the various embodiments of the present disclosure, the low band may be defined as the first band or first frequency band, the mid band as the second band or second frequency band, and the high band as the third band or third frequency band. Furthermore, since the above-mentioned problems mainly occur in the low band, the following describes a method to increase frequency band utilization with the low band as the primary target; however, the application of the following methods to the mid band or high band is not excluded. In various embodiments of the present disclosure, downlink transmission may mean downlink transmission of a base station and downlink reception of a terminal, and uplink transmission may mean uplink transmission of a terminal and uplink reception of a base station.

[0157] [Method 1-1]

[0158] If the terminal supports receiving based on switching between carriers prior to downlink carrier coupling, three main situations can be considered. The first is configured such that, as shown in FIG. 8, transmission and / or reception operations are performed only in one of the two low bands, LB (low band) 1 (801), during the interval T1 (802), and reception operations are performed without transmission in the other band LB2 (804) during the next time T2 (803). In this case, the other band LB2 (804) may refer only to downlink transmission in a general FDD band, or it may be a supplementary downlink (SDL) band. In the example of FIG. 8, in any case, the difference from conventional carrier coupling operations is that in the second interval T2 (803), only downlink transmission occurs in one band LB2 (804) and no uplink transmission occurs. In this case, since transmission and reception occur in only one band at any given moment, or only downlink reception is performed in one band, the problems that appear in conventional low-band carrier coupling can be resolved. Finally, in the next section T3 (805), the operation that occurred in T1 (802) is repeated, and general single-band transmission and reception occur.

[0159] [Method 1-2]

[0160] A second method, as shown in FIG. 9, is to first transmit and / or receive in one band LB1 (902) during the T1 (901) interval, and then stop all uplink transmissions and receive both downlink carriers of both bands during the next interval T2 (903). Specifically, after the interval T1 (901) in which transmission and / or reception operations are performed only in one of the low bands, LB1 (902), the system can be configured so that reception operations are performed without transmission in both LB1 (902) and LB2 (904) bands when the next interval T2 (903) arrives. At this time, the band LB2 (904) operating during the second interval T2 (903) may mean only downlink transmission in a general FDD band, or it may be a supplementary downlink (SDL) band. In the example of FIG. 9, the difference from conventional carrier coupling operation is that in any case, during the second T2 interval (903), only downlink transmission occurs in both bands (LB1 (902) and LB2 (903)), and no uplink transmission occurs. In this case, since transmission and reception occur in only one band at any given moment, or only downlink reception is performed in both bands, the problems that appear in conventional low-band carrier coupling can be resolved. Finally, in the next interval T3 (905), the operation that occurred in T1 (901) is repeated, and general single-band transmission occurs.

[0161] [Method 1-3]

[0162] As a third and final method, as shown in FIG. 10, transmission and / or reception are performed first at one band LB1 (1002) during the interval T1 (1001), and then at the next interval T2 (1003), transmission and / or reception are performed by switching to another band LB2 (1004). Specifically, in the interval T1 (1001), transmission and / or reception operations are performed only at one of the low bands, LB1 (1002), the transmission and / or reception at LB1 (1002) are stopped at the next time T2 (1003), and transmission and / or reception operations are performed at LB2 (1004). In this case, since LB2 (1004) is a band where both transmission and reception operations occur, the SDL band cannot be assumed in the example of FIG. 10. In this example, the difference from conventional carrier coupling operations is that only one band can be transmitted and received in any section. In this case, since transmission and reception occur in only one band without carrier coupling at any given moment, the problems associated with conventional low-band carrier coupling can be resolved. Finally, in the next section T3 (1005), the operation that occurred in T1 (1001) is repeated, and general single FDD band transmission occurs.

[0163] To summarize Methods 1-1, 1-2, and 1-3, when a terminal does not support general low-band carrier coupling, time-period carrier switching can be considered as a method to overcome hardware limitations of the terminal while efficiently utilizing low-band frequencies. In this case, as a switching scenario, the first (T1) and third (T3) periods are fixed as general single-band (LB1) transmission and reception, and as a scenario that may occur in the second period (T2), the terminal can select one of Methods 1-1, 1-2, and 1-3 and apply it during T2.

[0164] In the above methods 1-1, 1-2, and 1-3, transmitting from a specific LB in a specific interval (T) means that transmission is possible at the corresponding LB in that interval, but transmission does not always occur. That is, if there is a scheduling for transmission, a transmission operation may occur according to the scheduling. Receiving from a specific LB in a specific interval (T) means that reception is possible at the corresponding LB in that interval, but reception does not always occur. That is, if there is a scheduling for reception, a reception operation may occur according to the scheduling.

[0165] <Second Embodiment: Method for Setting Terminal Capability According to Terminal Structure for Switching-Based DL CA Support>

[0166] In the following, when a terminal performs such switching-based downlink carrier coupling to maximize frequency efficiency, a method is described in detail for selecting one of the three scenarios in which the terminal can support low-band carrier coupling as downlink carrier switching based on the terminal's hardware structure or other reasons, reporting the selected scenario as a terminal capability, and the operation of the terminal and the base station according to the terminal capability report.

[0167] First, the terminal can configure a carrier combination combination that performs carrier combination based on carrier-to-carrier switching operations in low-band carrier combination, along with other combinations for general carrier combination. In addition, band combinations capable of switching-based downlink reception can be reported per band combination through a new terminal capability [DLRxSwitchingBandPair], and together with this, the terminal can select a supported switching option and report it to the base station through a sub-terminal capability of [DLRxSwitchingBandPair], such as [downlinkRxSwitchingPeriod1], [downlinkRxSwitchingPeriod2], or [downlinkRxSwitchingPeriod3]. In various embodiments of the present disclosure, [downlinkRxSwitchingPeriod1] may correspond to the ability to indicate the switching option of [Method 1-1], [downlinkRxSwitchingPeriod2] may correspond to the ability to indicate the switching option of [Method 1-2], and [downlinkRxSwitchingPeriod3] may correspond to the ability to indicate the switching option of [Method 1-3]. Subsequently, when a terminal is instructed by a base station to receive one of the combinations of the above [DLRxSwitchingBandPair] reported, it may operate as follows, depending on the terminal ability [downlinkRxSwitchingPeriod1], [downlinkRxSwitchingPeriod2], or [downlinkRxSwitchingPeriod3] reported together therewith. In various embodiments of the present disclosure, parameters such as DLRxSwitchingBandPair and downlinkRxSwitchingPeriod are used to describe the performance of the terminal described above, and the names of such parameters are not limited thereto.

[0168] - [Method 2-1] When switching only to downlink reception operations in the LB2 band during the T2 period: If the terminal supports [Method 1-1] via [downlinkRxSwitchingPeriod1], for example, if [downlinkRxSwitchingPeriod1] exists, the carrier combination between the two bands is received on a switching basis, and the base station may schedule both downlink and uplink in the LB1 band during the first T1 period, and schedule only downlink in the LB2 band during the second T2 period. From the next T3 period onwards, the operations performed in the preceding T1 and T2 periods may be scheduled by repeating them alternately until the transmission of the corresponding combination of bandwidths is terminated. At this time, the terminal follows the scheduling instructions of the base station, and the LB2 band may be considered as the SDL band, which is a downlink-only band as previously mentioned, but is not limited thereto, and the LB2 band can be extended to a general FDD band.

[0169] - [Method 2-2] When switching to a downlink reception operation combining LB1 and LB2 bands during the T2 period: If the terminal supports [Method 1-2] through [downlinkRxSwitchingPeriod2], for example, if [downlinkRxSwitchingPeriod2] exists, the carrier combination between LB1 and LB2 bands is received on a switching basis, and the base station may schedule both downlink and uplink in a single band in the LB1 band during the first T1 period, and schedule combining only the downlink carrier by combining the LB1 and LB2 bands during the second T2 period. From the next T3 period onwards, the operations performed in the previous T1 and T2 periods may be scheduled by repeating them alternately until the transmission of the corresponding combination of bandwidths is terminated. At this time, the terminal follows the scheduling instructions of the base station, and the LB2 band may be considered as the SDL band, which is a downlink-only band as previously mentioned, but is not limited thereto, and the LB2 band can be extended to a general FDD band.

[0170] - [Method 2-3] When switching to the LB2 band during the T2 period: If the terminal supports [Method 1-3] via [downlinkRxSwitchingPeriod3], for example, if [downlinkRxSwitchingPeriod3] exists, the carrier combination between the two bands is received on a switching basis, and the base station may schedule both the downlink and uplink in a single band in the LB1 band during the first T1 period, and switch to the LB2 band during the second T2 period to schedule both the downlink and uplink in a single band. From the next T3 period onwards, the operations performed in the previous T1 and T2 periods may be scheduled by repeating them alternately until the transmission of the corresponding combination of bandwidths is terminated. At this time, the terminal follows the scheduling instructions of the base station, and only a general FDD band may be considered for the LB2 band.

[0171] In summary, the terminal may independently determine whether to support low-band carrier coupling (or the terminal performance regarding this) by considering the design of the terminal's hardware, receiver, etc., and may include band combinations of low-band carrier coupling that are supported by switching techniques in the BandCombinationList along with the existing list of carrier coupling band combinations, and report this to the base station. Although various embodiments of the present disclosure describe reporting information regarding band combinations of low-band carrier coupling supported by switching techniques by including them in the BandCombinationList, this is not limited thereto, and it is not excluded that such information may be included in other information fields of messages reporting terminal performance information. Among these, the list of carrier couplings that are supported based on switching may be reported separately by band combination via [DLRxSwitchingBandPair], and may also be reported to the base station in one or more ways via supported switching options [downlinkRxSwitchingPeriod1], [downlinkRxSwitchingPeriod2], or [downlinkRxSwitchingPeriod3]. At this time, when the base station instructs the terminal to the list of combinations included in [DLRxSwitchingBandPair], it may set up scheduling based on the information included in [downlinkRxSwitchingPeriod1], [downlinkRxSwitchingPeriod2], or [downlinkRxSwitchingPeriod3]. For example, assuming that the base station schedules the combinations included in [DLRxSwitchingBandPair] to the terminal, from the T1 interval where carrier coupling transmission begins, the base station instructs the terminal to transmit and / or receive uplink and downlink only in one band LB1, and the terminal can transmit uplink and receive downlink in the band LB1 instructed by the base station.Next, in the T2 interval, the base station may determine whether to schedule only the LB2 band downlink (Method 2-1), schedule only downlink transmission by combining the LB1 band and the LB2 band (Method 2-2), or schedule uplink and downlink by switching to the LB2 band (Method 2-3) by referring to [downlinkRxSwitchingBandPair] reported by the terminal. The terminal then proceeds with uplink transmission and / or downlink reception based on the settings of the base station.

[0172] <Third Embodiment: Switching Time and Interval Setting and Signaling / Terminal Capability Reporting Method>

[0173] In the following, when a terminal receives a downlink based on switching of a low-band carrier coupling, a method is specifically described for setting a location within the carrier reception interval where a condition for said switching occurs, for example, a change from T1 to T2 or from T2 to T3, and reporting this to the base station as a terminal capability, and for setting a maximum period during which the base station does not perform downlink transmission so that the terminal can change receivers when such switching occurs, and reporting this to the base station as a terminal capability.

[0174] As previously explained, the terminal can configure the switching combination to which switching operations are applied among the low-band carrier combinations in the BandCombinationList, which is a list of carrier combination combinations that supports other combinations for general carrier combination. In addition, the terminal can report the corresponding downlink switching-based combination through a new terminal capability [DLRxSwitchingBandPair], in which case the terminal can report to the base station as a terminal capability by setting the location and period during which switching occurs from T1 to T2 or from T2 to T3.

[0175] For example, the switching period that a terminal can report through the new terminal capability [downlinkRxSwitchingPeriod1], [downlinkRxSwitchingPeriod2], or [downlinkRxSwitchingPeriod3] can generally be considered in units of symbols constituting the carrier, and can be converted into time units based on the supporting Sub-carrier Spacing (SCS). That is, the switching period that a terminal can report through the terminal capability [downlinkRxSwitchingPeriod] can range from a minimum of 1 symbol time to an integer multiple of that time, which may be attributed to the terminal implementation, such as the terminal's receiver hardware structure. Depending on the supported bands and the receiver structure for each band, generally, if a single receiver supports only one band, the receiver control time may be reduced compared to a structure designed to support multiple bands. To support such diverse terminal designs, the switching time that a terminal can report through the terminal capability [downlinkRxSwitchingPeriod] can be reported to the base station as one of the values ​​in [Table 11] according to the SCS.

[0176] Symbol15kHz (us)30kHz (us)170352140703210105428014053501756420210

[0177] Based on the preceding embodiments and [Table 11], a new terminal capability [DLRxSwitchingBandPair] can be reported as shown in the following [Table 12].

[0178] DLRxSwitchingBandPair ::= SEQUENCE {bandIndexDL1 INTEGER(1..maxSimultaneousBands),bandIndexDL2 INTEGER(1..maxSimultaneousBands),downlinkRxSwitchingPeriod1 ENUMERATED {n35us, n70us, n105us, n140us},downlinkRxSwitchingPeriod2 ENUMERATED {n35us, n70us, n105us, n140us},downlinkRxSwitchingPeriod3 ENUMERATED {n35us, n70us, n105us, n140us}}

[0179] Additionally, the location where switching occurs from T1 to T2 or from T2 to T3 can be set as an RRC, and the interval where switching can occur can be set in various ways by considering the type of carrier, other downlink channels, etc. For example, in an embodiment of the present disclosure, as shown in FIG. 12, considering the characteristic that the downlink control channel (PDCCH), which is essential for terminal control of a base station, is placed at the beginning of the downlink slot, it can be assumed that this switching operation occurs from S0-X(us), which is before the switching time (Xus, 1202) reported by the terminal through [downlinkRxSwitchingPeriod1], [downlinkRxSwitchingPeriod2], or [downlinkRxSwitchingPeriod3] at the very end of the carrier slot (S0, 1201). In this case, the terminal can set [downlinkRxSwitchingPeriodLocation] to a TRUE value. If it is assumed that the terminal does not switch from time T0-X(us) prior to the end of the downlink carrier slot and switches at any other carrier location, [downlinkRxSwitchingPeriodLocation] may be reported as a FALSE value. In various embodiments of the present disclosure, downlinkRxSwitchingPeriodLocation is merely an example illustrating the previously described function and is not limited to the name of the parameter.

[0180] Combining the preceding embodiments, the terminal can operate as follows according to each scenario when supporting low-band carrier coupling through carrier switching.

[0181] [Method 3-1]

[0182] As shown in FIG. 11, when cross-band downlink carrier coupling is established and terminal capability [downlinkRxSwitchingPeriod1] exists (1101), specifically, when two downlink carriers are in different bands, the terminal can support switching between the two downlink carriers in the time axis according to the base station's scheduling instructions and rank adaptation. Here, supporting switching between the two downlink carriers means switching between the uplink carrier UL1 and downlink carrier DL1 of band LB1 and the downlink carrier DL2 of band LB2 in the first interval T1, and at this time, the terminal must support Layer 2 reception on both the downlink carrier DL1 and carrier DL2 that are switching (1102, 1103), and must also support single-layer transmission using one antenna port each. Here, carrier DL2 can be a carrier in a general band capable of both uplink and downlink transmission and reception, or a carrier in a downlink-only band (SDL). In other words, the layer of the downlink carrier supported at any given moment is the same.

[0183] As shown in FIG. 12, the portion where the switching period during which the terminal can switch is located may occur earlier by a switching time X (1202) from the beginning (1201) of each downlink carrier DL1 or downlink carrier DL2, as indicated by the RRC signaling [downlinkRxSwitchingPeriodLocation] by the base station. Here, the downlink switching length X must be smaller than [downlinkRxSwitchingPeriod1] reported as the terminal capability.

[0184] When switching from one carrier to another, if downlink transmission for the carrier prior to switching is not scheduled or set for at least X μs prior to the point in time when the terminal is scheduled or set to start receiving on the carrier after switching, the switching time must be fully contained within the time interval between the end of receiving on the carrier prior to switching and the start of receiving on the carrier after switching.

[0185] [Method 3-2]

[0186] As shown in FIG. 11, when cross-band downlink carrier coupling is established and terminal capability [downlinkRxSwitchingPeriod2] exists (1104), specifically, when two downlink carriers are in different bands, the terminal can support switching between the two downlink carriers in the time axis according to the base station's scheduling instructions and rank adaptation. Here, supporting switching between the two downlink carriers means switching between the uplink carrier UL1 and downlink carrier DL1 of band LB1 in the first interval T1 and between the downlink carrier DL1 of band LB1 and the downlink carrier DL2 of band LB2 in the second interval T2, and at this time, the terminal must support at least Layer 1 reception on the switching downlink carrier DL1 and carrier DL2 (1105, 1106). Here, carrier DL2 can be a carrier in a general band capable of both uplink and downlink transmission and reception, or a carrier in a downlink-only band (SDL). In other words, the total number of downlink carrier layers supported at any given moment is the same.

[0187] As shown in FIG. 12, the portion where the switching period during which the terminal can switch is located may occur earlier by a switching time X (1202) from the beginning (1201) of each downlink carrier DL1 or downlink carrier DL2, as indicated by the RRC signaling [downlinkRxSwitchingPeriodLocation] by the base station. Here, the downlink switching length X must be smaller than [downlinkRxSwitchingPeriod2] reported as the terminal capability.

[0188] When switching from one carrier to another, if downlink transmission for the carrier prior to switching is not scheduled or set for at least X μs prior to the point in time when the terminal is scheduled or set to start receiving on the carrier after switching, the switching time must be fully contained within the time interval between the end of receiving on the carrier prior to switching and the start of receiving on the carrier after switching.

[0189] [Method 3-3]

[0190] As shown in FIG. 11, when cross-band downlink carrier coupling is established and terminal capability [downlinkRxSwitchingPeriod3] exists (1107), specifically, when two downlink carriers are in different bands, the terminal can support switching between the two downlink carriers in the time axis according to the base station's scheduling instructions and rank adaptation. Here, supporting switching between the two downlink carriers means switching between uplink carrier UL1 and downlink carrier DL1 in band LB1 in the first interval T1 and between uplink carrier UL2 and downlink carrier DL2 in band 2 in the second interval T2, and at this time, the terminal must support Layer 2 reception on both the downlink carrier DL1 and carrier DL2 that are switching (1102, 1108), and must also support single-layer transmission using one antenna port each. In other words, the total number of layers of downlink carriers supported at any given moment is the same for all of them.

[0191] As shown in FIG. 12, the portion where the switching period during which the terminal can switch is located may occur earlier by a switching time X (1202) from the beginning (1201) of each downlink carrier DL1 or downlink carrier DL2, as indicated by the RRC signaling [downlinkRxSwitchingPeriodLocation] by the base station. Here, the downlink switching length X must be smaller than [downlinkRxSwitchingPeriod2] reported as the terminal capability.

[0192] When switching from one carrier to another, if downlink transmission for the carrier prior to switching is not scheduled or set for at least X μs prior to the point in time when the terminal is scheduled or set to start receiving on the carrier after switching, the switching time must be fully contained within the time interval between the end of receiving on the carrier prior to switching and the start of receiving on the carrier after switching.

[0193] Although Examples 1, 2, and 3 have been described separately above, this distinction is made for the convenience of explanation, and Examples 1, 2, and 3 all provide a switching method for efficiently using a carrier wave intended in this disclosure. Accordingly, Examples 1, 2, and 3 can be performed independently, and it is also possible to perform them by combining the contents of each example. In particular, it will be obvious to those skilled in the art that, depending on the description of each example, combinations of Method 1-1, Method 2-1, and Method 3-1, combinations of Method 1-2, Method 2-2, and 3-2, and combinations of Method 1-3, Method 2-3, and Method 3-3 are possible.

[0194] For example, in an embodiment of the present disclosure, the terminal can determine the performance for carrier switching. For example, scenarios for carrier switching may include scenarios such as Method 1-1, Method 1-2, and Method 1-3. Such performance of the terminal may be determined based on hardware limitations of the terminal, characteristics of the frequency band, characteristics of the surrounding area, etc.

[0195] The performance of a terminal to support the above-mentioned scenario may be reported to a base station according to the method of Embodiment 2. For example, the base station may transmit a terminal performance report request message to the terminal. The terminal may transmit terminal performance information to the base station based on the performance report request message. The terminal performance information may include information related to carrier switching. For example, it may include information corresponding to DLRxSwitchingBandPair and DLRxSwitchingBandPair described in the second embodiment, and may include downlinkRxSwitchingPeriod described in the third embodiment and information described in Table 12.

[0196] Meanwhile, information related to such carrier switching may be indicated through explicit information or through implicit methods. For example, if information related to carrier switching is reported to a base station, the base station may determine that the terminal has the capability for carrier switching.

[0197] The terminal reports terminal performance information to the base station in the manner described above, and the base station receiving this information can perform a scheduling operation based on carrier switching based on the terminal's performance information. For example, the terminal and the base station can perform performance information reporting and scheduling operations according to the methods described in Method 2-1, Method 2-2, and Method 2-3.

[0198] When switching occurs according to this method, carrier switching can be performed at the switching time confirmed according to Method 3-1, Method 3-2, and Method 3-3 described in the third embodiment.

[0199] As such, it should be noted that the first embodiment, the second embodiment, and / or the third embodiment may be combined with each other.

[0200] The above-described flowchart illustrates an exemplary method that may be implemented in accordance with the principles of the present disclosure, and various modifications may be made to the method illustrated in the flowchart in this specification. For example, although illustrated as a series of steps, the various steps in each figure may overlap, occur in parallel, occur in a different order, or occur multiple times. In other examples, each step may be omitted or replaced with another step.

[0201] FIG. 13 is a drawing illustrating the structure of a terminal in a wireless communication system according to one embodiment of the present disclosure.

[0202] Referring to FIG. 13, the terminal may include a transceiver (referring to a terminal receiver (1300) and a terminal transmitter (1310)), a memory (not shown), and a terminal processing unit (1305, or a terminal control unit or processor). The transceiver (1300, 1310), memory, and terminal processing unit (1305) of the terminal may operate according to at least one or a combination thereof of the methods corresponding to the above-described embodiments. However, the components of the terminal are not limited to the illustrated examples. For example, according to other embodiments, the terminal may include more or fewer components than the components described above. Furthermore, in certain cases, the transceiver, memory, and processor may be implemented in the form of a single chip.

[0203] The transceiver (1300, 1310) can transmit and receive signals with a base station. Here, the signal may include control information and data. To this end, the transceiver (1300, 1310) may be configured to include an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. However, this is merely one embodiment of the transceiver (1300, 1310), and the components of the transceiver (1300, 1310) are not limited to an RF transmitter and an RF receiver.

[0204] Additionally, the transceiver (1300, 1310) can receive a signal through a wireless channel and output it to a processor (1305), and transmit the signal output from the processor (1305) through a wireless channel.

[0205] Memory can store programs and data necessary for the operation of the terminal. Additionally, memory can store control information or data included in signals transmitted and received by the terminal. Memory may be composed of storage media or combinations of storage media such as ROM, RAM, hard disk, CD-ROM, and DVD. Additionally, there may be multiple memories.

[0206] Additionally, the processor (1305) can control a series of processes to enable the terminal to operate according to the above-described embodiment. For example, the processor (1305) can perform or control the operation of the terminal to perform at least one of the methods according to the embodiments of the present disclosure or a combination thereof. There may be multiple processors (1305), and the processor (1305) can perform component control operations of the terminal by executing a program stored in memory.

[0207] FIG. 14 is a drawing illustrating the structure of a base station in a wireless communication system according to one embodiment of the present disclosure.

[0208] Referring to FIG. 14, the base station may include a transceiver unit, referring to a base station receiver (1400) and a base station transmitter (1410), a memory (not shown), and a base station processing unit (1405, or a base station control unit or processor). According to at least one or a combination thereof of the methods corresponding to the above-described embodiments, the transceiver unit (1400, 1410), the memory, and the base station processing unit (1405) of the base station may be operated. However, the components of the base station are not limited to the illustrated examples. For example, according to other embodiments, the base station may include more components or fewer components than the components described above. In addition, the transceiver unit, the memory, and the processor may be implemented in the form of a single chip.

[0209] The transceiver (1400, 1410) can transmit and receive signals with a terminal. Here, the signal may include control information and data. To this end, the transceiver (1400, 1410) may be configured to include an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. However, this is merely one embodiment of the transceiver (1400, 1410), and the components of the transceiver (1400, 1410) are not limited to an RF transmitter and an RF receiver.

[0210] Additionally, the transceiver (1400, 1410) can receive a signal through a wireless channel and output it to a processor (1405), and transmit the signal output from the processor (1405) through a wireless channel.

[0211] Memory can store programs and data necessary for the operation of the base station. Additionally, memory can store control information or data included in signals transmitted and received by the base station. Memory can be composed of storage media or combinations of storage media such as ROM, RAM, hard disk, CD-ROM, and DVD. Additionally, there may be multiple memories.

[0212] The processor (1405) can control a series of processes to enable the base station to operate according to the embodiments of the present disclosure described above. For example, the processor (1405) can perform or control the operation of the base station to perform at least one of the methods according to the embodiments of the present disclosure or a combination thereof. There may be multiple processors (1405), and the processor (1405) can perform component control operations of the base station by executing a program stored in memory.

[0213] Methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0214] When implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. One or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of this disclosure.

[0215] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), magnetic disc storage devices, CD-ROM (Compact Disc-ROM), Digital Versatile Discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they may be stored in memory composed of some or all of these. Additionally, each constituent memory may include multiple units.

[0216] Additionally, the program may be stored on an attachable storage device accessible via a communication network such as the Internet, Intranet, Local Area Network (LAN), Wide LAN (WLAN), or Storage Area Network (SAN), or a combination thereof. Such a storage device may be connected to the device performing the embodiment of the present disclosure through an external port. Additionally, a separate storage device on the communication network may be connected to the device performing the embodiment of the present disclosure.

[0217] In the specific embodiments of the present disclosure described above, the components included in the invention are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural form, it may be composed of a singular form, or even if a component is expressed in the singular form, it may be composed of a plural form.

[0218] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples provided to facilitate the explanation of the technical content of the present disclosure and to aid in understanding the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to those skilled in the art that other variations based on the technical concept of the present disclosure are possible. Furthermore, each of the above embodiments may be combined and operated as needed. For example, parts of one embodiment of the present disclosure and parts of another embodiment may be combined to operate a base station and a terminal. For example, parts of the first embodiment and the second embodiment of the present disclosure may be combined to operate a base station and a terminal. In addition, although the above embodiments are presented based on an FDD LTE system, other variations based on the technical concept of the above embodiments may be implemented in other systems such as TDD (time division duplex) LTE systems, 5G, or NR systems.

[0219] Meanwhile, the order of description in the drawings illustrating the method of the present invention does not necessarily correspond to the order of execution, and the order of execution may be changed or executed in parallel.

[0220] Alternatively, drawings describing the method of the present invention may omit some components and include only some components to the extent that the essence of the present invention is not impaired.

[0221] In addition, the method of the present invention may be implemented by combining some or all of the contents included in each embodiment within a scope that does not impair the essence of the invention.

[0222] Various embodiments of the present disclosure have been described above. The foregoing description of the present disclosure is for illustrative purposes only and is not limited to the embodiments disclosed. Those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present disclosure. The scope of the present disclosure is defined by the claims set forth below rather than by the foregoing detailed description, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included within the scope of the present disclosure.

Claims

1. A method performed by a terminal in a wireless communication system, A step of receiving a terminal capability enquiry (UE capability enquiry) message from a base station; and The method includes the step of transmitting a terminal performance information (UE capability information) message to the base station, which includes first information indicating support for LB-LB CA (carrier aggregation) based on switching of a first LB (low band) supporting FDD (frequency division duplex) and a second LB supporting SDL (supplementary downlink), based on the reception of the terminal performance inquiry message. A method in which, based on the above first information, in a first section where transmission or reception is performed in the FDD band of the first LB, reception is not performed in the SDL of the second LB, and in a second section where reception is performed in the SDL band of the second LB, transmission or reception is not performed in the FDD band of the first LB.

2. In Paragraph 1, The above terminal performance information message includes second information indicating the length of the switching time of the first LB and the second LB, and A method in which the length of the above switching time is in microseconds.

3. In Paragraph 2, A method in which the switching of the first LB and the second LB is performed in the last slot of the first section.

4. In Paragraph 1, The above terminal performance information message includes second information indicating support for the LB-LB CA based on the switching of the first LB supporting the FDD and the second LB supporting the SDL, and A method in which, based on the above second information, reception is not performed in the SDL of the second LB in the above first section, and reception operation of the first LB is performed in the above second section.

5. In a method performed by a base station in a wireless communication system, A step of transmitting a terminal capability enquiry (UE capability enquiry) message to the terminal; and The method includes the step of receiving a terminal capability information (UE capability information) message from the terminal, which includes first information indicating support for LB-LB CA (carrier aggregation) based on switching of a first LB (low band) supporting FDD (frequency division duplex) and a second LB supporting SDL (supplementary downlink), based on the transmission of the terminal capability inquiry message. A method in which, based on the above first information, in a first section where transmission or reception is performed in the FDD band of the first LB, reception is not performed in the SDL of the second LB, and in a second section where reception is performed in the SDL band of the second LB, transmission or reception is not performed in the FDD band of the first LB.

6. In Paragraph 5, The above terminal performance information message includes second information indicating the length of the switching time of the first LB and the second LB, and A method in which the length of the above switching time is in microseconds.

7. In Paragraph 6, A method in which the switching of the first LB and the second LB is performed in the last slot of the first section.

8. In Paragraph 5, The above terminal performance information message includes second information indicating support for the LB-LB CA based on the switching of the first LB supporting the FDD and the second LB supporting the SDL, and A method in which, based on the above second information, reception is not performed in the SDL of the second LB in the above first section, and reception operation of the first LB is performed in the above second section.

9. In a terminal of a wireless communication system, Memory for storing instructions; and Connected to the above memory, and at least partially based on the execution of the above instructions, the terminal, Received a terminal capability enquiry message from the base station, and A processing circuit configured to transmit a terminal performance information (UE capability information) message to the base station, the message including first information indicating support for LB-LB CA (carrier aggregation) based on switching of a first LB (low band) supporting FDD (frequency division duplex) and a second LB supporting SDL (supplementary downlink), based on the reception of the terminal performance inquiry message. A terminal in which, based on the above first information, reception is not performed in the SDL of the second LB during a first section in which transmission or reception is performed in the FDD band of the first LB, and transmission or reception is not performed in the FDD band of the first LB during a second section in which reception is performed in the SDL band of the second LB.

10. In Paragraph 9, The above terminal performance information message includes second information indicating the length of the switching time of the first LB and the second LB, and A terminal in which the length of the above switching time is in microseconds.

11. In Paragraph 10, The switching of the first LB and the second LB is performed at the last slot of the first section.

12. In Paragraph 9, The above terminal performance information message includes second information indicating support for the LB-LB CA based on the switching of the first LB supporting the FDD and the second LB supporting the SDL, and A terminal in which, based on the second information above, reception is not performed in the SDL of the second LB in the first section, and reception operation of the first LB is performed in the second section.

13. In a base station of a wireless communication system, Memory for storing instructions; and Connected to the above memory, and at least partially based on the execution of the above instructions, the base station, Send a UE capability enquiry message to the terminal, and A processing circuit configured to receive a terminal capability information (UE capability information) message from the terminal, the message including first information indicating support for LB-LB CA (carrier aggregation) based on switching of a first LB (low band) supporting FDD (frequency division duplex) and a second LB supporting SDL (supplementary downlink), based on the transmission of the terminal capability inquiry message. A base station in which, based on the above first information, reception is not performed in the SDL of the second LB during a first section in which transmission or reception is performed in the FDD band of the first LB, and transmission or reception is not performed in the FDD band of the first LB during a second section in which reception is performed in the SDL band of the second LB.

14. In Paragraph 13, The above terminal performance information message includes second information indicating the length of the switching time of the first LB and the second LB, and A base station where the length of the above switching time is in microseconds.

15. In Paragraph 14, The switching of the first LB and the second LB is performed at the base station in the last slot of the first section.

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