Methods and apparatus for communication in next-generation mobile communication systems

Abstract

This disclosure relates to a method performed by a terminal, the method comprising: sending capability information associated with time division multiplexing (TDM) operation to a first base station; receiving from the first base station a radio resource control (RRC) connection reconfiguration message including a TDM mode associated with dual connectivity (DC) of the first base station and a second base station; and sending uplink signals based on the TDM mode.

Description

[0001] This application is a divisional application of the invention patent application filed on September 26, 2017, with application number 201780059438.9 and invention title "Method and apparatus for communication in a next-generation mobile communication system". Technical Field

[0002] This disclosure relates to a method and apparatus for communicating in a next-generation mobile communication system. More specifically, this disclosure relates to a method and apparatus for configuring and transmitting a Physical Uplink Control Channel (PUCCH) in a next-generation mobile communication system that uses analog beamforming technology in conjunction with multiple antennas. Background Technology

[0003] To meet the ever-growing demand for wireless data services since the release of fourth-generation (4G) communication systems, efforts have been made to develop and improve fifth-generation (5G) communication systems, or pre-5G communication systems. Therefore, 5G communication systems or pre-5G communication systems are also referred to as "beyond 4G networks" or "post-LTE systems." To achieve higher data rates, the implementation of 5G communication systems in higher frequency (mmWave) bands, such as the 60GHz band, is being considered. To reduce radio wave propagation loss and increase transmission distance, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive MIMO technologies have been discussed in 5G communication systems. Furthermore, research and development is underway in 5G communication systems focusing on system network improvements based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, cooperative multipoint (CoMP), and receiver interference cancellation. In 5G systems, hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) modulation (FQAM) as advanced coding and modulation (ACM), as well as sliding window superposition coding (SWSC), and filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) have been developed as advanced access technologies.

[0004] The internet, as a human-centric network of connections where information is generated and used, is now evolving into the Internet of Things (IoT), in which distributed entities, such as things, exchange and process information without human intervention. The Internet of Everything (IoE), a combination of IoT technology and big data processing technology connected to cloud servers, has emerged. Because realizing IoT requires technological elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology, sensor networks, machine-to-machine (M2M) communication, and machine-type communication (MTC) have been recently researched. Such an IoT environment can provide intelligent internet technology services, creating new value for human life by collecting and analyzing data generated between connected things. Through the integration and combination of existing information technology (IT) with various industrial applications, IoT can be applied to various fields, including smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0005] Consistent with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, MTC, and M2M communication have been implemented using beamforming, MIMO, and array antennas. The application of RAN, as a big data processing technology described above, can also be seen as an example of the convergence of 5G and IoT technologies.

[0006] The above information is provided as background information to aid in understanding this disclosure. No decision has been made or any statement has been made regarding whether any of the above content can be used as prior art to this disclosure. Summary of the Invention

[0007] Technical issues

[0008] The aspects of this disclosure are intended to at least address the aforementioned problems and / or defects, and to provide at least the following advantages.

[0009] Currently, in Long Term Evolution (LTE) systems, time and frequency resources are used to allocate and configure Physical Uplink Control Channel (PUCCH) resources, and PUCCH resources are used to transmit PUCCH. However, in next-generation mobile communication systems using analog beamforming techniques with multiple antennas, it is necessary to consider beam direction. Furthermore, if a new cell or base station architecture is defined, the method for configuring and transmitting PUCCH needs to be adapted accordingly. Accordingly, one aspect of this disclosure is to provide a method and apparatus for configuring and transmitting PUCCH in a next-generation mobile communication system.

[0010] Another aspect of this disclosure is to provide an apparatus and method for packet loss recovery in a wireless communication system while providing multiple connections.

[0011] Another aspect of this disclosure proposes a method for a terminal to measure signals in a wireless communication system performing beam-based communication.

[0012] Another aspect of this disclosure is to provide a signaling radio bearer (SRB) related configuration and operation so that terminals and base stations can correctly send and receive control messages when the base station and terminals perform a process to restore the connection when needed after suspending their connection in a wireless communication system.

[0013] Another aspect of this disclosure is to provide operation of base stations and terminals so that the terminals and base stations correctly send and receive control messages when the base stations and terminals resume their connections as needed after suspending them in a wireless communication system.

[0014] Technical solution

[0015] According to one aspect of this disclosure, a method for operating a terminal is provided. The method includes: receiving a first RRC message including information for Radio Resource Control (RRC) connection suspension; maintaining Signaling Radio Bearer (SRB) 0 and suspending Data Radio Bearer (DRB) and at least one other SRB based on the first RRC message; sending a second RRC message to a base station via SRB 0 for requesting RRC connection restoration; receiving a third RRC message from the base station via SRB 1 for RRC connection restoration; and restoring SRB 2 and DRB based on the third RRC message.

[0016] According to another aspect of this disclosure, a terminal is provided. The terminal includes: a transceiver configured to transmit and receive signals; and a controller configured to receive a first RRC message including information for Radio Resource Control (RRC) connection suspension, maintain Signaling Radio Bearer (SRB) 0 and suspend Data Radio Bearer (DRB) and at least one other SRB based on the first RRC message, transmit a second RRC message to a base station via SRB0 for requesting RRC connection restoration, receive a third RRC message from the base station via SRB1 for RRC connection restoration, and restore SRB2 and DRB based on the third RRC message.

[0017] According to another embodiment of this disclosure, a method for operating a base station is provided. The method includes: sending a first RRC message to a terminal including information for Radio Resource Control (RRC) connection suspension; receiving a second RRC message from the terminal via Signaling Radio Bearer (SRB) 0 for requesting RRC connection restoration; sending a third RRC message to the terminal via SRB1 for RRC connection restoration; and restoring SRB2 and Data Radio Bearer (DRB) based on the third RRC message. While SRB0 is held based on the first RRC message, DRB and at least one other SRB are suspended; and SRB1 is not suspended until the third RRC message is received.

[0018] According to another embodiment of this disclosure, a base station is provided. The base station includes: a transceiver configured to transmit and receive signals; and a controller configured to transmit a first RRC message to a terminal including information for Radio Resource Control (RRC) connection suspension, receive a second RRC message from the terminal via Signaling Radio Bearer (SRB) 0 for requesting RRC connection restoration, transmit a third RRC message to the terminal via SRB1 for RRC connection restoration, and restore SRB2 and Data Radio Bearer (DRB) based on the third RRC message. While SRB0 is held based on the first RRC message, the DRB and at least one other SRB are suspended; and SRB1 is not in a suspended state until the third RRC message is received.

[0019] According to another embodiment of this disclosure, a method performed by a terminal is provided, the method comprising: sending capability information associated with time division multiplexing (TDM) operation to a first base station; receiving from the first base station a radio resource control (RRC) connection reconfiguration message including a TDM mode associated with dual connectivity (DC) of the first base station and a second base station; and sending an uplink signal based on the TDM mode.

[0020] According to another embodiment of this disclosure, a terminal is provided, including: a transceiver; and a controller coupled to the transceiver and configured to: send capability information associated with Time Division Multiplexing (TDM) operation to a first base station, receive from the first base station a Radio Resource Control (RRC) connection reconfiguration message including a TDM mode associated with dual connectivity (DC) of the first and second base stations, and send uplink signals based on the TDM mode.

[0021] According to another embodiment of this disclosure, a method performed by a first base station is provided, the method comprising: receiving capability information associated with time division multiplexing (TDM) operation from a terminal; sending a radio resource control (RRC) connection reconfiguration message to the terminal including a TDM mode associated with dual connectivity (DC) of the first base station and a second base station; and receiving uplink signals based on the TDM mode.

[0022] According to another embodiment of this disclosure, a first base station is provided, including: a transceiver; and a controller coupled to the transceiver and configured to: receive capability information associated with time division multiplexing (TDM) operation from a terminal, send a radio resource control (RRC) connection reconfiguration message to the terminal including a TDM mode associated with dual connectivity (DC) of the first base station and a second base station, and receive uplink signals based on the TDM mode.

[0023] Beneficial effects

[0024] According to one aspect of this disclosure, efficient PUCCH transmission becomes feasible through a method for configuring and transmitting PUCCH in accordance with next-generation mobile communication systems (NR).

[0025] According to another aspect of this disclosure, the terminal can prevent data loss even if the connection configuration is changed or canceled while providing multiple connections.

[0026] According to another aspect of this disclosure, after determining suitable transmit and receive beams, the terminal can measure the strength and quality of a reference signal (RS) at predetermined intervals based on a specific downlink receive beam, without needing to continuously measure all beams, thereby reducing the terminal's power consumption.

[0027] According to another aspect of this disclosure, SRB-related configurations and operations are specified in cases where the base station and the terminal suspend their connection in a wireless communication system and then restore the connection when needed, thereby enabling the terminal and the base station to correctly send and receive control messages.

[0028] According to another aspect of this disclosure, in the case where the base station and the terminal restore their connection after suspending it in the wireless communication system, the operation of the base station and the terminal is clearly checked, thereby enabling the base station and the terminal to correctly send and receive control messages.

[0029] Other aspects, advantages, and salient features of this disclosure will become clear to those skilled in the art from the following detailed description of various embodiments disclosed in conjunction with the accompanying drawings. Attached Figure Description

[0030] Figure 1AThis is a diagram illustrating the structure of a next-generation mobile communication system to which this disclosure can be applied, according to embodiments of the present disclosure;

[0031] Figure 1B This is a diagram illustrating beam scanning of a next-generation mobile communication system applicable to embodiments of this disclosure, according to embodiments of the disclosure.

[0032] Figure 1C This is a diagram illustrating the subframe structure of a next-generation mobile communication system to which this disclosure can be applied, according to embodiments of this disclosure.

[0033] Figure 1D This is a diagram illustrating the structure of another next-generation mobile communication system to which this disclosure can be applied, according to embodiments of this disclosure;

[0034] Figure 1E This is a diagram illustrating a method for configuring and transmitting the Physical Uplink Control Channel (PUCCH) in the Radio Resource Control (RRC) layer of a Central Unit (CU) according to an embodiment 1-1 of this disclosure;

[0035] Figure 1F This is a diagram illustrating a method 1 for configuring and transmitting PUCCH using the RRC layer of the CU and the Media Access Control (MAC) layer of the Distribution Unit (DU) according to embodiments 1-2 of this disclosure;

[0036] Figure 1G This is a diagram illustrating method 2 for configuring and sending PUCCH using the RRC layer of the CU and the MAC layer of the DU according to embodiments 1-3 of this disclosure;

[0037] Figure 1H This is a diagram illustrating method 3 for configuring and sending PUCCH using the RRC layer of the CU and the MAC layer of the DU according to embodiments 1-4 of this disclosure;

[0038] Figure 1I This is a diagram illustrating the operation of a terminal according to the embodiments described above in accordance with this disclosure;

[0039] Figure 1J This is a block diagram illustrating the configuration of a terminal according to an embodiment of the present disclosure;

[0040] Figure 1K This is a block diagram illustrating the configuration of a base station transceiver according to an embodiment of the present disclosure;

[0041] Figure 2A This is a diagram illustrating the structure of a Long Term Evolution (LTE) system for reference according to an embodiment of the present disclosure;

[0042] Figure 2BThis is a diagram illustrating the radio protocol structure of an LTE system for reference according to an embodiment of the present disclosure;

[0043] Figure 2C This is a diagram illustrating the frame structure used in a 5G system to which this disclosure is applied, according to an embodiment of the present disclosure;

[0044] Figure 2D This is a diagram illustrating the message flow between a terminal and a base station when using a method for selectively determining the beam to be measured according to a measurement configuration, according to an embodiment of the present disclosure.

[0045] Figure 2E This is a diagram illustrating the sequence of operations of a terminal that applies the present disclosure according to embodiments of the present disclosure;

[0046] Figure 2F This is a diagram illustrating the configuration of a terminal according to an embodiment of the present disclosure;

[0047] Figure 3A This is a diagram illustrating a multi-connection operation scheme in a next-generation mobile communication system according to embodiments of the present disclosure;

[0048] Figure 3B This is an illustration illustrating a terminal having multiple radio frequency (RF) chains for supporting multiple connections, according to embodiments of the present disclosure;

[0049] Figure 3C This is a diagram illustrating the application of a time division multiplexing (TDM) method for supporting multiple connections according to embodiments of the present disclosure;

[0050] Figure 3D This is a diagram illustrating a terminal having a single RF chain for applying a TDM method according to an embodiment of the present disclosure;

[0051] Figure 3E This is a diagram illustrating a terminal having a single TX chain and multiple RX chains for applying a TDM method, according to an embodiment of the present disclosure;

[0052] Figure 3F This is a diagram illustrating the third-first embodiment of configuring TDM type multiple connections according to embodiments of the present disclosure;

[0053] Figure 3G This is a diagram illustrating the operation of a terminal according to the third-first embodiment of this disclosure;

[0054] Figure 3H This is a diagram illustrating the operation of the first base station according to the third-1 embodiment of this disclosure;

[0055] Figure 3IThis is a diagram illustrating the third-second embodiment of configuring TDM-type multiple connections according to embodiments of the present disclosure;

[0056] Figure 3J This is a diagram illustrating the operation of the first base station according to the third-second embodiment of this disclosure;

[0057] Figure 3K This is a diagram illustrating a scheme for explaining the method of releasing TDM according to embodiments of the present disclosure;

[0058] Figure 3L This is a block diagram illustrating the configuration of a terminal according to an embodiment of the present disclosure;

[0059] Figure 3M This is a diagram illustrating the configuration of a base station according to an embodiment of the present disclosure;

[0060] Figure 4A This is a diagram illustrating the structure of a next-generation mobile communication system according to an embodiment of the present disclosure;

[0061] Figure 4B This is a diagram illustrating the frame structure used by an NR system applying this disclosure according to an embodiment of the present disclosure;

[0062] Figure 4C This is a diagram illustrating radio link monitoring (RLM) operation in an existing LTE system according to embodiments of the present disclosure;

[0063] Figure 4D This is a diagram illustrating radio link failure (RLF) operation in an existing LTE system according to embodiments of the present disclosure;

[0064] Figure 4E This is a diagram illustrating the conceptual explanation of RLF operation in a next-generation mobile communication system according to embodiments of the present disclosure;

[0065] Figure 4F This is a diagram illustrating the serving beams and beam groups under RLM / RLF in a next-generation mobile communication system according to embodiments of the present disclosure;

[0066] Figure 4G This is a diagram illustrating RLM operation according to embodiments of the present disclosure;

[0067] Figure 4H This is a diagram illustrating the operation of a terminal under RLM / RLF according to embodiments of the present disclosure;

[0068] Figure 4I This is a diagram illustrating the first process according to an embodiment of the present disclosure;

[0069] Figure 4JThis is a diagram illustrating the first process according to an embodiment of the present disclosure;

[0070] Figure 4K This is a diagram illustrating the configuration of a terminal according to an embodiment of the present disclosure;

[0071] Figure 4L This is a diagram illustrating the configuration of a base station according to an embodiment of the present disclosure;

[0072] Figure 5A This is a diagram illustrating the structure of an LTE system according to an embodiment of the present disclosure;

[0073] Figure 5B This is a diagram illustrating the radio protocol structure of an LTE system according to an embodiment of the present disclosure;

[0074] Figure 5C This is a diagram illustrating the operation of RLF-related terminals and networks according to embodiments of this disclosure;

[0075] Figure 5D This is a diagram illustrating the operation of a terminal and network involving an RRC connection suspend / resume process according to embodiments of this disclosure;

[0076] Figure 5E This is a diagram illustrating the operation of a terminal according to an embodiment of the present disclosure;

[0077] Figure 5F This is a diagram illustrating the configuration of a terminal according to an embodiment of the present disclosure;

[0078] Figure 5G This is a diagram illustrating the configuration of a base station according to an embodiment of the present disclosure;

[0079] Figure 6A This is a diagram illustrating the structure of an LTE system according to an embodiment of the present disclosure;

[0080] Figure 6B This is a diagram illustrating the radio protocol structure of an LTE system according to an embodiment of the present disclosure;

[0081] Figure 6C This is a diagram illustrating the process of network suspending and terminal connection according to the 6-1 embodiment of the present disclosure;

[0082] Figure 6D This is a diagram illustrating the process of restoring connection between a terminal and a network according to embodiment 6-1 of this disclosure;

[0083] Figure 6E This is a diagram illustrating the operation of a terminal according to embodiment 6-1 of this disclosure;

[0084] Figure 6FThis is a diagram illustrating the process of network suspend and terminal connection according to embodiment 6-2 of this disclosure; and

[0085] Figure 6G This is a diagram illustrating the process of restoring connection between a terminal and a network according to embodiment 6-2 of this disclosure. Detailed Implementation

[0086] The following description, with reference to the accompanying drawings, is provided to aid in a full understanding of the various embodiments of this disclosure as defined by the claims and their equivalents. The description includes various specific details that aid in understanding, but these should be considered merely exemplary. Accordingly, those skilled in the art will recognize that various changes and modifications can be made to the various embodiments described herein without departing from the scope and spirit of this disclosure. Furthermore, for clarity and brevity, descriptions of well-known functions and constructions may be omitted.

[0087] The terms and words used in the following description and claims are not limited to their literal meaning, but are merely intended by the inventors to achieve a clear and consistent understanding of this disclosure. Accordingly, it will be clear to those skilled in the art that the following description of various embodiments of this disclosure is for illustrative purposes only and is not intended to limit the purpose of this disclosure, which is defined by the claims and their equivalents.

[0088] It should be understood that the singular forms “a,” “one,” and “the” include plural meanings unless the context explicitly indicates otherwise. Thus, as an example, the reference to “a component surface” includes the reference to one or more such surfaces.

[0089] The aspects and features of this disclosure, as well as the methods for implementing said aspects and features, will become clear from reference to the embodiments described in detail with reference to the accompanying drawings. However, this disclosure is not limited to the embodiments disclosed below, but may be implemented in reverse order. The content defined in the specification, such as detailed constructions and elements, is provided only to assist those skilled in the art in fully understanding the specific details of the disclosure, which is defined only by the scope of the claims. Throughout the description of this disclosure, and throughout the accompanying drawings, the same reference numerals are used for the same parts.

[0090] <First Embodiment>

[0091] Embodiments of this disclosure relate to a method and apparatus for configuring and transmitting the Physical Uplink Control Channel (PUCCH) in a next-generation mobile communication system (New Radio (NR) or 5G) and a terminal may include the following operations:

[0092] —The terminal receives the first information via a Radio Resource Control (RRC) message (Layer 3 message).

[0093] —The first information may include the format of type 1 PUCCH and the format of type 2 PUCCH. The information about the format may be an integer between a predetermined minimum value and a predetermined maximum value.

[0094] —Information about the format indicates the size of the PUCCH and the content that will be placed in the PUCCH.

[0095] —The first information can indicate the frequency resources used for channel state information (SCI) measurements.

[0096] —Type 1 PUCCH can be sent periodically. Furthermore, Type 1 PUCCH can be sent periodically according to a specific period indicated by the second information.

[0097] The transmission of a Type 1 PUCCH can be triggered by MAC control information (or MAC control element) that includes second information.

[0098] —Type 1 PUCCH may include periodic CSIs. Information such as the Channel Quality Indicator (CQI), Precoding Matrix Indicator (PMI), and Rank Indicator (RI) may be included in the CSI.

[0099] —Type 2 PUCCH can be sent periodically. Furthermore, it can be sent n times. The integer n can be indicated in the first or second message.

[0100] The transmission of a Type 2 PUCCH can be triggered by downlink control information (DCI) that includes third-party information.

[0101] —Type 2PUCCH may include periodic CSI.

[0102] —The operation of the terminal receiving second information through Media Access Control (MAC) control messages (MAC control messages or MAC control elements).

[0103] —The second information may include the transmission period of the Type 1 PUCCH or transmission resource information (frequency resources or time resources) for the Type 1 PUCCH.

[0104] —The terminal receives third-party information through PHY control messages (physical control information in PDCCH or DCI).

[0105] —The third information may include the number of Type 2 PUCCH transmissions or transmission resource information (frequency resources or time resources) for Type 2 PUCCH.

[0106] —The terminal sends either type 1 PUCCH or type 2 PUCCH.

[0107] —The terminal may apply first information or second information and may use an uplink beam with a specific direction to transmit type 1 PUCCH.

[0108] —The terminal may apply first or third information and may use uplink beams with a specific direction to transmit type 2PUCCH.

[0109] —An uplink beam with a specific direction can be a beam determined by the most recent random access procedure performed by the terminal. Furthermore, an uplink beam with a specific direction can be a beam with an uplink direction consistent with the direction of the downlink beam serving the terminal is currently being served. Additionally, an uplink beam with a specific direction can be an uplink beam selected through an optimal beam pairing selection process performed by the terminal and the base station. The optimal beam selection process involves the base station transmitting downlink beams supported by the base station at specific time intervals, and the terminal using uplink beams supported by the terminal to check all feasible pairs of downlink and uplink beams, and then selecting the pair with the highest signal quality.

[0110] —The operation of the terminal receiving the first message from the network.

[0111] —The first message can be an RRC message.

[0112] —The first message includes at least one first piece of information.

[0113] —The terminal confirms whether the second information is included in the first message.

[0114] —If the second information is included in the first message, the terminal sends a type 1 PUCCH operation after receiving the first message.

[0115] —The transmission of type 1 PUCCH is performed based on the first information of the first message and the second information of the first message.

[0116] —Type 1 PUCCH transmission is performed by an uplink beam with a specific direction.

[0117] —An uplink beam with a specific direction can be a beam determined by the most recent random access procedure performed by the terminal. Furthermore, an uplink beam with a specific direction can be a beam with an uplink direction consistent with the downlink beam direction of the serving beam currently being served by the terminal. Additionally, an uplink beam with a specific direction can be indicated by the network. Furthermore, an uplink beam with a specific direction can be an uplink beam selected through an optimal beam pairing selection process performed by the terminal and the base station. The optimal beam selection process refers to the following process: the base station transmits downlink beams supported by the base station at specific time periods; the terminal uses uplink beams supported by the terminal to check all feasible pairs of downlink and uplink beams, and then selects the pair with the highest signal quality.

[0118] —If the second information is included in the first message, the terminal sends a type 1 PUCCH operation after receiving the second information.

[0119] —The transmission of type 1 PUCCH is performed based on the first information of the first message and the second information of the second message.

[0120] —The second message can be a MAC control message.

[0121] —Type 1 PUCCH transmission is performed by an uplink beam with a specific direction.

[0122] —An uplink beam with a specific direction can be a beam determined by the most recent random access procedure performed by the terminal. Furthermore, an uplink beam with a specific direction can be a beam with an uplink direction consistent with the downlink beam direction of the serving beam currently being served by the terminal. Additionally, an uplink beam with a specific direction can be indicated by the network. Furthermore, an uplink beam with a specific direction can be an uplink beam selected through an optimal beam pairing selection process performed by the terminal and the base station. The optimal beam selection process refers to the following process: the base station transmits downlink beams supported by the base station at specific time periods; the terminal uses uplink beams supported by the terminal to check all feasible pairs of downlink and uplink beams, and then selects the pair with the highest signal quality.

[0123] The embodiments of this disclosure have the configuration and PUCCH transmission process described above, and will be described in more detail below with reference to the accompanying drawings.

[0124] Figure 1A This is a diagram illustrating the structure of a next-generation mobile communication system to which this disclosure can be applied, according to embodiments of the present disclosure.

[0125] Reference Figure 1AThe radio access network of the next-generation mobile communication system consists of the new radio point node B (NR NB) 1a-10 and the new radio core network (NR CN) 1a-05. User terminals (new radio user equipment (NR UE)) 1a-15 connect to the external network through NR NB 1a-10 and NR CN 1a-05.

[0126] exist Figure 1A In this context, NR NB 1a-10 corresponds to the evolved Node B (eNB) of the existing LTE system. The NRNB connects to NR UE 1a-15 via radio channels, thereby providing superior service compared to the existing Node B. Since all user traffic is served through a shared channel, it is necessary to have a device to perform scheduling by consolidating state information such as buffer state, available transmit power state, and channel state for each UE, and NR NB 1a-10 is responsible for this process. An NR NB typically controls multiple cells. To achieve ultra-high data transmission speeds compared to existing LTE, the NR NB may have a bandwidth equal to or greater than the existing maximum bandwidth, and orthogonal frequency division multiplexing (OFDM) can be considered in conjunction with beamforming technology as a radio connection technology. Furthermore, an adaptive modulation and coding (AMC) method is applied to the NR NB to determine the modulation scheme and channel coding rate to match the terminal's channel state. NR CN 1a-05 performs mobility support, bearer configuration, and quality of service (QoS) configuration. The NR CN is a device responsible not only for terminal mobility management but also for various types of control functions, and it connects to multiple base stations. Furthermore, the next-generation mobile communication system can be interlocked with the existing LTE system, and the NRCN connects to the Mobility Management Entity (MME) 1a-25 via a network interface. The MME connects to the eNB 1a-30, which serves as an existing base station.

[0127] Figure 1B This is a diagram illustrating beam scanning applicable to a next-generation mobile communication system according to embodiments of this disclosure.

[0128] Reference Figure 1BNR aims to support increased data transmission speeds compared to existing LTE. As a method for improving data transmission speeds in NR, methods using wideband frequencies existing in the 6GHz or higher frequency range have been considered for signal transmission. That is, millimeter wave (hereinafter referred to as "mmWave") bands, such as the 28GHz or 60GHz bands, have been considered to increase transmission rates. The frequency bands considered for mmWave have relatively large signal attenuation per unit distance; therefore, to ensure coverage, transmission based on directional beams generated using multiple antennas is necessary. The problem with directional beam transmission is the difficulty in transmitting or receiving signals in locations where no beam is formed. To overcome this problem, beam scanning technology is used. Beam scanning technology is a technique in which a transmitting device transmits a directional beam or rotates a directional beam with a constant beamwidth while continuously scanning, so that a receiving device located within the beam reach distance of the transmitting device receives the beam. For example, a transmit / receive point (TRP) 1b-05 is a device that transmits and receives radio signals in the network and can be a 5G NB or a device connected to a 5G NB. The TRP can transmit a directional beam with a specific width in a specific direction at a specific time t1, and a directional beam with the same width in another direction at time t2, so that the beam covers all directions during a specific time period. As a result, the downlink signal transmitted by the base station arrives at terminal 1b-15 at time t9 and at terminal 1b-10 at time t4.

[0129] Beam sweeping is mainly used when the base station does not know the direction of the directional beam to be applied to the terminal. It also transmits the common overhead signal (OSF) to the idle terminal (idle terminal) through beam sweeping.

[0130] To improve beam efficiency, both transmit and receive directional beams can be used. If a receive directional beam is used, the directionality of the transmit and receive beams must be synchronized. For example, if the directionality of the receive beam is not synchronized with that of the transmit beam, the terminal (1b-20) will be unable to receive the transmit beam even if it is located within the transmit beam's area. Conversely, if the directionality of the transmit and receive beams is synchronized and the terminal (1b-25) is located within the transmit beam's area, data can be transmitted and received with significantly higher efficiency compared to not using a receive beam.

[0131] To find a receiving beam that is synchronized with the transmitting beam, the receiving device searches for the receiving beam that provides the best reception quality by applying different receiving beams to the same transmitting beam. This process is called receiving beam scanning.

[0132] Figure 1C This is a diagram illustrating the subframe structure of a next-generation mobile communication system applicable to embodiments of this disclosure.

[0133] Reference Figure 1C In mobile communication systems using directional beams, analog beams, or hybrid beams, a common overhead signal (OSF) is transmitted by beam scanning in a specific subframe, and user data can be transmitted to or received from a specific terminal using a directional beam in a single direction in another subframe.

[0134] The subframe that has already been received (OSF 1c-05) is repeatedly transmitted during a predetermined period 1c-10. A subframe consists of multiple symbols, and in the OSF, a directional beam is transmitted for each symbol. For example, a directional beam (or analog beam) is transmitted, where the first symbol 1c-15 to the eleventh symbol 1c-25 correspond to times t1 to t11, respectively. Each symbol has the same beamwidth but covers different areas, and the directivity is configured along different directions.

[0135] The following overhead signals can be sent for each symbol of the OSF.

[0136] —Signals used for downlink synchronization establishment, such as the primary synchronization signal (PSS) and secondary synchronization signal (SSS).

[0137] —Beam Reference Signal (BRS) enables the measurement of received signal strength or received signal quality for each beam.

[0138] —System information, Master Information Block (MIB), or Physical Broadcast Channel (PBCH).

[0139] —The PBCH includes the necessary information for terminal access to the 1d system, such as downlink beam bandwidth or system frame number.

[0140] For reference, the Public Land Mobile Network (PLMN) identifier can be broadcast through a channel other than the MIB.

[0141] In a subframe where OSF transmission is not periodic, the same beam is transmitted over several consecutive symbols, and user data for a specific terminal in a connected state can be transmitted through this beam. Hereinafter, this subframe is referred to as a Data Subframe (DSF) 1c-30.

[0142] Figure 1D This is a diagram illustrating the structure of another next-generation mobile communication system to which this disclosure can be applied, according to embodiments of the present disclosure.

[0143] Reference Figure 1DA cell served by a beam-operated NR base station (NR gNB) 1d-05 can be composed of TRPs 1d-10, 1d-15, 1d-20, 1d-25, 1d-30, 1d-35, and 1d-40. TRPs 1d-10, 1d-15, 1d-20, 1d-25, 1d-30, 1d-35, and 1d-40 indicate blocks obtained by separating the transmission and reception of physical signals from existing LTE base station eNBs, and include multiple antennas. The NR base station can be represented as a central unit (CU), and the TRP can be represented as a distributed unit (DU). The functionality of the NR gNB and TRP can be configured by separating the individual layers 1d-45 from the Packet Data Convergence Protocol (PDCP) / Radio Link Control (RLC) / MAC / Physical (PHY) layers. In other words, TRP 1d-15 and ld-25 can perform the functions of layers corresponding only to the PHY layer; TRP 1d-10, ld-35, and ld-40 can perform the functions of layers corresponding only to the PHY and MAC layers; and TRP 1d-20 and ld-30 can perform the functions of layers corresponding only to the PHY, MAC, and RLC layers. Specifically, TRP 1d-10, 1d-15, 1d-20, 1d-25, 1d-30, 1d-35, and 1d-40 can use beamforming technology, which generates narrow beams in several directions using multiple transmit / receive antennas to transmit and receive data. User terminal ld-50 connects to NR gNB ld-05 and external networks via TRP 1d-10, 1d-15, 1d-20, 1d-25, 1d-30, 1d-35, and 1d-40. In order to provide services to users, NR gNBld-05 supports the connection between the terminal and the core network (CN) by performing scheduling through merging the state information of each terminal (such as buffer state, available transmit power state, and channel state).

[0144] Embodiments of this disclosure present a next-generation mobile communication system architecture as described above, and provide methods and apparatus for configuring and transmitting PUCCH within the system described above. Transmission resources for transmitting PUCCH can be configured based on time and frequency resources. However, in next-generation mobile communication systems, methods such as... Figure 1B The beamforming technique shown uses a narrow beam; therefore, when transmitting a PUCCH, it is necessary to consider time resources, frequency resources, and even beam direction. Furthermore, in next-generation mobile communications, such as... Figure 1D As shown, a CU (or gNB) can connect to several DUs (TRPs), and the layers and functions of each TRP can be different from each other. Accordingly, when configuring the PUCCH, the following should be considered:

[0145] —PUCCH can be received and processed in TRP.

[0146] — PUCCH transmission resources can be controlled by TRP.

[0147] —The PUCCH transmission beam can be controlled by the TRP.

[0148] In this structure, it is difficult for a single CU to manage functions such as... Figure 1D All terminals exist in the larger area shown. That is, due to the backhaul delay between the CU and DU(TRP), it is difficult for the CU to send control signals to the terminals, and the complexity is significantly increased because the CU should perform a lot of signal processing for the terminals.

[0149] Figure 1E This is a diagram illustrating a method for configuring a PUCCH and transmitting configuration information in the RRC layer of a CU according to an embodiment 1-1 of this disclosure.

[0150] Reference Figure 1E The CU 1e-03 or gNB may have a PDCP / RLC / MAC layer, and the DU or TRP 1e-02 may only have a PHY layer. Accordingly, the CU can manage the scheduling of transmission resources. In next-generation mobile communication systems, if it is necessary to configure the PUCCH of terminal 1e-01 for specific reasons, the CU 1e-03 determines the PUCCH transmission configuration information for the corresponding terminal. The PUCCH transmission configuration information may include the PUCCH transmission period, PUCCH format (format for periodic CSI and format for aperiodic CSI), transmission resource size, transmission resource information (time information and frequency information), transmit beam information, receive beam information, and the number of aperiodic CSI transmissions. The transmission resource information may include the number of subframes indicating the period, the system frame number indicating the activation time, the subframe number (SFN), the resource block (RB) index indicating frequency resources, and the symbol index indicating time resources.

[0151] If the PUCCH transmission configuration information is determined, then in operation 1e-05, CU 1e-03 transmits the information to TRP 1e-02. Furthermore, in operation 1e-10, CU 1e-03 configures the PUCCH by sending the information to terminal 1e-01 as an RRC message. In operation 1e-15, terminal 1e-01, for which the PUCCH has been configured from the RRC message, can use the PUCCH transmission configuration information received from operation 1e-10 to report periodic CSIs to TRP 1e-02 as the PUCCH format and transmission resources for the periodic CSIs. When reporting periodic CSIs, terminal 1e-01 can use an uplink beam with a specific direction to transmit the periodic CSIs.

[0152] An uplink beam with a specific direction can be a beam determined by the most recent random access procedure performed by terminal 1e-01. Furthermore, an uplink beam with a specific direction can be a beam with an uplink direction consistent with the downlink beam direction of the serving beam currently being served by terminal 1e-01. Additionally, an uplink beam with a specific direction can be indicated by the network. Furthermore, an uplink beam with a specific direction can be an uplink beam selected through an optimal beam pairing selection process performed by terminal 1e-01 and the base station. The optimal beam selection process refers to the following process: the base station transmits downlink beams supported by the base station at specific time periods; terminal 1e-01 uses uplink beams supported by the terminal to check all feasible pairs of downlink and uplink beams, and then selects the pair with the highest signal quality.

[0153] If, for specific reasons, CU 1e-03 needs to receive aperiodic CSI from terminal 1e-01, then in operations 1e-20 and 1e-25, CU 1e-03 is configured to receive aperiodic CSI from TRP 1e-02, and TRP allocates PUCCH or PUSCH transmission resources from PDCCH to DCI to terminal 1e-01 for the aperiodic CSI. In operation 1e-30, terminal 1e-01 reports the aperiodic CSI to TRP 1e-02 using the PUCCH format configured for aperiodic CSI in operation 1e-10 and the transmission resources configured in operation 1e-20. The aperiodic CSI may be transmitted consecutively n times, or transmitted according to a determined rule. The integer n may be included in the PUCCH transmission configuration information. The integer n may be indicated in the first or second information.

[0154] When reporting aperiodic CSI, terminal 1e-01 may use an uplink beam with a specific direction to transmit the aperiodic CSI. The uplink beam with a specific direction may be a beam determined by the most recent random access procedure performed by terminal 1e-01. Furthermore, the uplink beam with a specific direction may be a beam with an uplink direction consistent with the downlink beam direction of the serving beam currently being served by the terminal. Additionally, the uplink beam with a specific direction may be indicated by the network. Furthermore, the uplink beam with a specific direction may be an uplink beam selected by an optimal beam pairing selection process performed by terminal 1e-01 and the base station to select the optimal beam pairing. The optimal beam selection process refers to the following process: the base station transmits downlink beams supported by the base station at specific time periods; terminal 1e-01 uses the uplink beams supported by terminal 1e-01 to check all feasible pairs of downlink and uplink beams, and then selects the pair with the highest signal quality.

[0155] Figure 1F This is a diagram illustrating a method 1 for configuring the PUCCH and transmitting configuration information using the RRC layer of the CU and the MAC layer of the DU according to embodiments 1-2 of this disclosure.

[0156] Reference Figure 1F DU or TRP 1d-10, 1d-20, 1d-30, 1d-35, and 1d-40 may have a MAC layer. Correspondingly, TRP1f-02 manages the scheduling of transmission resources. In next-generation mobile communication systems, if it is necessary to configure the PUCCH of terminal 1f-01 for specific reasons, CU 1f-03 determines the PUCCH transmission configuration information of terminal 1f-01. The PUCCH transmission configuration information determined by CU 1f-03 may include the PUCCH transmission period (the number of subframes indicating the period, the system frame number indicating the activation time, and the SFN), the PUCCH format (the format for periodic CSI and the format for aperiodic CSI), the transmission resource size, the transmit beam information, the receive beam information, and the number of aperiodic CSI transmissions. If the PUCCH transmission configuration information is determined, then in operation 1f-05, CU 1f-03 transmits the information to TRP 1f-02.

[0157] TRP 1f-02 receives PUCCH transmission configuration information and determines the actual transmission resource information for the PUCCH. The transmission resource information may include the system frame number indicating the activation time, the SFN, the RB index indicating frequency resources, the symbol index indicating time resources, transmit beam information, and receive beam information. If the transmission resource information is determined, in operation 1f-10, TRP 1f-02 configures the PUCCH of terminal 1f-01 by sending the PUCCH transmission resource information together with the PUCCH transmission configuration information received from operation 1f-05 to terminal 1f-01 as a MAC control message (MAC control information or MAC control element).

[0158] In operation 1f-15, terminal 1f-01, which has configured PUCCH for its MAC control message, can use the PUCCH transmission configuration information received from operation 1f-10 to report periodic CSIs to TRP 1f-02 as the PUCCH format and transmission resources for periodic CSIs. When reporting periodic CSIs, terminal 1f-01 can use an uplink beam with a specific direction to transmit the periodic CSIs. The uplink beam with a specific direction can be a beam determined by the most recently performed random access procedure of terminal 1f-01. Furthermore, the uplink beam with a specific direction can be a beam with an uplink direction consistent with the downlink beam direction of the serving beam currently served by terminal 1f-01. Additionally, the uplink beam with a specific direction can be indicated by the network. Furthermore, the uplink beam with a specific direction can be an uplink beam selected through an optimal beam pairing selection process performed by terminal 1f-01 and the base station. The optimal beam selection process refers to the following process: the base station sends downlink beams supported by the base station according to a specific time period, and the terminal 1f-01 uses uplink beams supported by the terminal to check all feasible pairs of downlink and uplink beams, and then selects the pair with the highest signal quality.

[0159] If, for specific reasons, TRP 1f-02 or CU 1f-03 needs to receive aperiodic CSI from terminal 1f-01, then in operation 1f-20, TRP allocates PUCCH or PUSCH transmission resources from PDCCH to DCI to the terminal for aperiodic CSI. In operation 1f-25, terminal 1e-01 reports the aperiodic CSI to TRP using the PUCCH format for aperiodic CSI configured in operation 1f-10 and the transmission resources configured in operation 1f-20. The aperiodic CSI may be transmitted consecutively n times, or according to a determined rule. The integer n may be included in the PUCCH transmission configuration information. When reporting aperiodic CSI, terminal 1f-01 may use an uplink beam with a specific direction to transmit the aperiodic CSI. The uplink beam with a specific direction may be the beam determined by the most recently executed random access procedure of terminal 1f-01. Furthermore, an uplink beam with a specific direction can be a beam with an uplink direction consistent with the direction of the downlink beam that is currently being served by the terminal. Additionally, an uplink beam with a specific direction can be indicated by the network. Furthermore, an uplink beam with a specific direction can be an uplink beam selected by an optimal beam pairing selection process performed by the terminal 1f-01 and the base station to select the best beam pairing. The optimal beam selection process refers to the following process: the base station transmits downlink beams supported by the base station at specific time periods; the terminal 1f-01 uses uplink beams supported by the terminal to check all feasible pairs of downlink and uplink beams, and then selects the pair with the highest signal quality. As confirmation of good signal reception during the process described above, MAC control messages (MAC control information or MAC control elements) can be used.

[0160] Figure 1G This is a diagram illustrating method 2 for configuring PUCCH and sending configuration information using the RRC layer of the CU and the MAC layer of the DU according to embodiments 1-3 of this disclosure.

[0161] Reference Figure 1GDU or TRP 1d-10, 1d-20, 1d-30, 1d-35, and 1d-40 may have a MAC layer. Correspondingly, TRP1g-02 manages the scheduling of transmission resources. In next-generation mobile communication systems, if it is necessary to configure the PUCCH of terminal 1g-01 for specific reasons, CU 1g-03 or gNB determines the PUCCH transmission configuration information of terminal 1g-01. The PUCCH transmission configuration information determined by CU 1g-03 may include the PUCCH transmission period (the number of subframes indicating the period, the system frame number indicating the activation time, and the SFN), the PUCCH format (the format for periodic CSI and the format for aperiodic CSI), the transmission resource size, the transmit beam information, the receive beam information, and the number of aperiodic CSI transmissions. If the PUCCH transmission configuration information is determined, then in operation 1g-05, the CU transmits the information to the TRP. In addition, during operation 1g-10, CU 1g-03 configures the PUCCH transmission configuration information by directly sending the PUCCH transmission configuration information to terminal 1g-01 as an RRC message.

[0162] TRP 1g-02 receives PUCCH transmission configuration information from CU 1g-03 and determines the actual transmission resource information for the PUCCH. The transmission resource information may include a system frame number indicating the activation time, an SFN, an RB index indicating frequency resources, a symbol index indicating time resources, transmit beam information, and receive beam information. If the transmission resource information is determined, in operation 1g-15, TRP 1g-02 configures the PUCCH of terminal 1g-01 by sending the PUCCH transmission resource information as a MAC control message (MAC control information or MAC control element) to the terminal. In operation 1g-20, terminal 1g-01, whose PUCCH transmission resources have been allocated from the MAC control message, can use the PUCCH transmission configuration information received from operation 1g-10 as the PUCCH format for periodic CSI to report periodic CSI to TRP. When reporting periodic CSI, the terminal can use an uplink beam with a specific direction to transmit the periodic CSI.

[0163] An uplink beam with a specific direction can be a beam determined by the most recent random access procedure performed by terminal 1g-01. Furthermore, an uplink beam with a specific direction can be a beam with an uplink direction consistent with the downlink beam direction of the serving beam currently served by terminal 1g-01. Additionally, an uplink beam with a specific direction can be indicated by the network. Furthermore, an uplink beam with a specific direction can be an uplink beam selected through an optimal beam pairing selection process performed by terminal 1g-01 and the base station to select the optimal beam pairing. The optimal beam selection process refers to the following process: the base station transmits downlink beams supported by the base station at specific time periods; terminal 1g-01 uses uplink beams supported by the terminal to check all feasible pairs of downlink and uplink beams, and then selects the pair with the highest signal quality.

[0164] If, for specific reasons, TRP 1b-02 or CU 1g-03 needs to receive aperiodic CSI from terminal 1g-01, then in operation 1g-25, TRP allocates PUCCH or PUSCH transmission resources from PDCCH to DCI to terminal 1g-01 for aperiodic CSI. In operation 1g-30, terminal 1g-01 reports the aperiodic CSI to TRP using the PUCCH format for aperiodic CSI configured in operation 1g-10 and the transmission resources configured in operation 1g-25. The aperiodic CSI may be transmitted consecutively n times, or according to a determined rule. The integer n may be included in the PUCCH transmission configuration information. When reporting aperiodic CSI, terminal 1g-01 may use an uplink beam with a specific direction to transmit the aperiodic CSI.

[0165] An uplink beam with a specific direction can be a beam determined by the most recent random access procedure performed by terminal 1g-01. Furthermore, an uplink beam with a specific direction can be a beam with an uplink direction consistent with the direction of the downlink beam serving the beam currently being served by terminal 1g-01. Additionally, an uplink beam with a specific direction can be indicated by the network. Furthermore, an uplink beam with a specific direction can be an uplink beam selected through an optimal beam pairing selection process performed by terminal 1g-01 and the base station. The optimal beam selection process refers to the following process: the base station transmits downlink beams supported by the base station at specific time periods; terminal 1g-01 uses uplink beams supported by terminal 1g-01 to check all feasible pairs of downlink and uplink beams, and then selects the pair with the highest signal quality. As confirmation of good signal reception during the process described above, MAC control messages (MAC control information or MAC control elements) can be used.

[0166] Figure 1H This is a diagram illustrating method 3 for configuring and sending PUCCH using the RRC layer of the CU and the MAC layer of the DU according to embodiments 1-4 of this disclosure.

[0167] Reference Figure 1H DU or TRP 1d-10, 1d-20, 1d-30, 1d-35, and 1d-40 may have a MAC layer. Correspondingly, TRP1h-02 manages the scheduling of transmission resources. In next-generation mobile communication systems, if it is necessary to configure the PUCCH of terminal 1h-01 for specific reasons, CU 1h-03 or gNB determines the PUCCH transmission configuration information for the corresponding terminal. The PUCCH transmission configuration information determined by CU 1h-03 may include the PUCCH transmission period (the number of subframes indicating the period, the system frame number indicating the activation time, and the SFN), the PUCCH format (format for periodic CSI and format for aperiodic CSI), the transmission resource size, the transmit beam information, the receive beam information, and the number of aperiodic CSI transmissions. If the PUCCH transmission configuration information is determined, CU 1h-03 transmits the information to TRP 1h-02 during operation 1h-05.

[0168] Then, TRP 1h-02 receives PUCCH transmission configuration information from CU 1h-03 and determines the actual transmission resource information for the PUCCH. The transmission resource information may include the system frame number indicating the activation time, SFN, RB index indicating frequency resources, symbol index indicating time resources, transmit beam information, and receive beam information. If the transmission resource information is determined, in operation 1h-10, TRP 1h-02 transmits the PUCCH transmission resource information to terminal 1h-03. Then, in operation 1h-05, CU 1h-03 configures the PUCCH transmission configuration information and transmission resource information for terminal 1h-01 as an RRC control message. In operation 1h-20, terminal 1h-01, with the PUCCH configured, can use the PUCCH configuration information and PUCCH transmission resource information to report periodic CSI to TRP 1h-02 as a PUCCH format for periodic CSI. When reporting periodic CSI, the terminal can use an uplink beam with a specific direction to transmit the periodic CSI.

[0169] An uplink beam with a specific direction can be a beam determined by the most recent random access procedure performed by terminal 1h-01. Furthermore, an uplink beam with a specific direction can be a beam with an uplink direction consistent with the downlink beam direction of the serving beam currently being served by terminal 1h-01. Additionally, an uplink beam with a specific direction can be indicated by the network. Furthermore, an uplink beam with a specific direction can be an uplink beam selected through an optimal beam pairing selection process performed by terminal 1h-01 and the base station. The optimal beam selection process refers to the following process: the base station transmits downlink beams supported by the base station at specific time periods; terminal 1h-01 uses uplink beams supported by terminal 1h-01 to check all feasible pairs of downlink and uplink beams, and then selects the pair with the highest signal quality.

[0170] If, for specific reasons, TRP 1h-02 or CU 1h-03 needs to receive aperiodic CSI from terminal 1h-01, then in operation 1h-25, TRP 1h-02 allocates PUCCH or PUSCH transmission resources from PDCCH to DCI to terminal 1h-01 for aperiodic CSI. In operation 1h-30, terminal 1h-01 reports the aperiodic CSI to TRP 1h-02 using the PUCCH format for aperiodic CSI configured in operation 1h-10 and the transmission resources configured in operation 1h-25. The aperiodic CSI can be sent consecutively n times, or sent according to a determined rule. The integer n can be included in the PUCCH transmission configuration information. When reporting aperiodic CSI, terminal 1h-01 can use an uplink beam with a specific direction to send the aperiodic CSI.

[0171] An uplink beam with a specific direction can be a beam determined by the most recent random access procedure performed by terminal 1h-01. Furthermore, an uplink beam with a specific direction can be a beam with an uplink direction consistent with the direction of the downlink beam serving the beam currently being served by terminal 1h-01. Additionally, an uplink beam with a specific direction can be indicated by the network. Furthermore, an uplink beam with a specific direction can be an uplink beam selected through an optimal beam pairing selection process performed by terminal 1g-01 and the base station to select the optimal beam pairing. The optimal beam selection process refers to the following process: the base station transmits downlink beams supported by the base station at specific time periods; terminal 1h-01 uses uplink beams supported by terminal 1h-01 to check all feasible pairs of downlink and uplink beams, and then selects the pair with the highest signal quality. As confirmation of good signal reception during the process described above, MAC control messages (MAC control information or MAC control elements) can be used.

[0172] Figure 1I This is a diagram illustrating the operation of a terminal according to the embodiments described above in accordance with this disclosure.

[0173] Reference Figure 1I In operation 1i-01, the terminal receives a control message. In operation 1i-05, the control message can be identified as one of the following: an RRC message, a MAC control message (MAC control information or MAC control element), or a DCI of the PDCCH.

[0174] If the control message is an RRC message or a MAC control message, then in operation 1i-10, the terminal first confirms the PUCCH transmission configuration information. That is, the terminal confirms whether the PUCCH transmission has been configured or whether the PUCCH transmission configuration information is included in the received control message. The PUCCH transmission configuration information may include the PUCCH transmission period, PUCCH format (format for periodic CSI and format for aperiodic CSI), transmission resource size, transmit beam information, receive beam information, and the number of aperiodic CSI transmissions.

[0175] If the PUCCH transmission configuration has been completed or the PUCCH transmission configuration information is included in the received control message, the terminal proceeds to operation 1i-15. In operation 1i-15, the terminal confirms whether the PUCCH transmission resource information is included in the control message. The transmission resource information (time information and frequency information) may include the number of subframes indicating the period, the system frame number indicating the activation time, the SFN, the RB index indicating the frequency resource, and the symbol index indicating the time resource.

[0176] If the PUCCH transmission resource information for periodic CSI is confirmed in operation 1i-15, then the terminal triggers periodic CSI in operation 1i-20. If the PUCCH transmission configuration information and PUCCH transmission resource configuration information for periodic CSI are not confirmed in operation 1i-10 or operation 1i-15, then the terminal executes another operation corresponding to the command in the control message in operation 1i-25.

[0177] If a DCI is received in operation 1i-05, then in operation 1i-30, the terminal confirms whether information regarding PUCCH transmission resources for aperiodic CSI is included in the DCI. If information regarding PUCCH transmission resources for aperiodic CSI is included in the DCI, then in operation 1i-35, the terminal triggers aperiodic CSI. If information regarding PUCCH transmission resources for aperiodic CSI is not included in the DCI, then in operation 1i-25, the terminal performs another operation based on another command included in the DCI.

[0178] Terminal operation is not limited to Figure 1I The operation may include, as referred above, the following. Figures 1A to 1H All operations of the terminal mentioned above.

[0179] Figure 1J This is a diagram illustrating the configuration of a terminal according to an embodiment of the present disclosure.

[0180] Reference Figure 1J The terminal includes a radio frequency (RF) processor 1j-10, a baseband processor 1j-20, a storage unit 1j-30, and a controller 1j-40.

[0181] RF processor 1j-10 performs functions for transmitting and receiving signals via a radio channel, such as signal band conversion and amplification. Specifically, RF processor 1j-10 performs up-conversion of baseband signals provided by baseband processor 1j-20 to RF band signals for transmission to the antenna, and down-conversion of RF band signals received by the antenna back to baseband signals. For example, RF processor 1j-10 may include transmit filters, receive filters, amplifiers, mixers, oscillators, digital-to-analog converters (DACs), and analog-to-digital converters (ADCs). Although only one antenna is shown in the figures, the terminal may be provided with multiple antennas. Furthermore, RF processor 1j-10 may include multiple RF chains. Additionally, RF processor 1j-10 can perform beamforming. For beamforming, RF processor 1j-10 can adjust the phase and magnitude of signals transmitted or received through multiple antennas or wire elements. Furthermore, the RF processor can perform multiple-input multiple-output (MIMO) and can receive multiple layers during MIMO operation. The RF processor 1j-10 can perform receive beam sweep by appropriately configuring multiple antennas or antenna elements under the control of the controller, or it can control the direction and beamwidth of the receive beam to synchronize the receive beam with the transmit beam.

[0182] The baseband processor 1j-20 performs the conversion between baseband signals and bit strings according to the system's physical layer (PHY) standard. For example, during data transmission, the baseband processor 1j-20 generates complex symbols by encoding and modulating the transmitted bit string. Furthermore, during data reception, the baseband processor 1j-20 recovers the received bit string by demodulating and decoding the baseband signal provided from the RF processor 1j-10. For example, following the OFDM method, during data transmission, the baseband processor 1j-20 generates complex symbols by encoding and modulating the transmitted bit string, performs mapping of the complex symbols to subcarriers, and then configures the OFDM symbols through inverse fast Fourier transform (IFFT) operations and cyclic prefix (CP) insertion. In addition, during data reception, the baseband processor 1j-20 divides the baseband signal provided by the RF processor 1j-10 into units of OFDM symbols, recovers the signal mapped onto the subcarrier through Fast Fourier Transform (FFT) operation, and then recovers the received bit string through demodulation and decoding.

[0183] The baseband processor 1j-20 and RF processor 1j-10 can transmit and receive signals as described above. Therefore, the baseband processor 1j-20 and RF processor 1j-10 can be referred to as a transmitter, receiver, transceiver, or communication unit. Furthermore, to support different radio connectivity technologies, at least one of the baseband processor 1j-20 and RF processor 1j-10 may include multiple communication modules. Additionally, to process signals in different frequency bands, at least one of the baseband processor 1j-20 and RF processor 1j-10 may include different communication modules. For example, different radio connectivity technologies may include LTE networks and NR networks. Furthermore, different frequency bands may include ultra-high frequency (SHF) bands (e.g., 2.5 GHz or 5 GHz) and millimeter wave (mmWave) bands (e.g., 60 GHz, etc.).

[0184] Storage unit 1j-30 stores data containing basic programs, application programs, and configuration information for the operation of the terminal. Storage unit 1j-30 provides the stored data according to requests from controller 1j-40.

[0185] Controller 1j-40 controls the overall operation of the terminal. For example, controller 1j-40 can send and receive signals via baseband processor 1j-20 and RF processor 1j-10. Furthermore, controller 1j-40 records data in or reads data from storage unit 1j-30. For this purpose, controller 1j-40 may include at least one processor. For example, controller 1j-40 may include a communication processor (CP) that performs control for communication and an application processor (AP) that controls higher-level functions such as applications, and may include a multi-connection processor 1j-42.

[0186] Figure 1K This is a diagram illustrating the configuration of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0187] Reference Figure 1K The base station includes an RF processor 1k-10, a baseband processor 1k-20, a backhaul communication unit 1k-30, a storage unit 1k-40, and a controller 1k-50.

[0188] RF processor 1k-10 performs functions for transmitting and receiving signals via a radio channel, such as signal band conversion and amplification. Specifically, RF processor 1k-10 performs up-conversion of baseband signals provided by baseband processor 1k-20 to RF band signals for transmission to the antenna, and down-conversion of RF band signals received by the antenna back to baseband signals. For example, RF processor 1k-10 may include transmit filters, receive filters, amplifiers, mixers, oscillators, DACs, and ADCs. Although only one antenna is shown in the figures, the first connection node may provide multiple antennas. Furthermore, RF processor 1k-10 may include multiple RF chains. Additionally, RF processor 1k-10 can perform beamforming. For beamforming, RF processor 1k-10 can adjust the phase and magnitude of signals transmitted or received through multiple antennas or antenna elements. Furthermore, the RF processor can perform downlink MIMO operation by transmitting one or more layers.

[0189] The baseband processor 1k-20 performs the conversion between baseband signals and bit strings according to the PHY standard of the first radio connection technology. For example, during data transmission, the baseband processor 1k-20 generates complex symbols by encoding and modulating the transmitted bit string. Furthermore, during data reception, the baseband processor 1k-20 recovers the received bit string by demodulating and decoding the baseband signal provided from the RF processor 1k-10. For example, following the OFDM method, during data transmission, the baseband processor 1k-20 generates complex symbols by encoding and modulating the transmitted bit string, performs mapping of the complex symbols to subcarriers, and then configures the OFDM symbols through IFFT operations and CP insertion. Furthermore, during data reception, the baseband processor 1k-20 divides the baseband signal provided from the RF processor 1k-10 into units of OFDM symbols, recovers the signal mapped to the subcarriers through FFT operations, and then recovers the received bit string through demodulation and decoding. The baseband processor 1k-20 and RF processor 1k-10 can transmit and receive signals as described above. Therefore, the baseband processor 1k-20 and RF processor 1k-10 can be referred to as a transmitter, receiver, transceiver, or communication unit.

[0190] The backhaul communication unit 1k-30 provides an interface for performing communication with other nodes in the network.

[0191] Storage unit 1k-40 stores data containing basic procedures, application programs, and configuration information for the operation of the main base station. Specifically, storage unit 1k-40 can store information about bearers assigned to connected terminals and measurement results reported from connected terminals. Furthermore, storage unit 1k-40 can store information that determines whether to provide multiple connections to terminals or suspend multiple connections to terminals. Additionally, storage unit 1k-40 can provide stored data upon request from controller 1k-50.

[0192] The controller 1k-50 controls the overall operation of the main base station. For example, the controller 1k-50 transmits and receives signals via the baseband processor 1k-20 and the RF processor 1k-10 or via the backhaul communication unit 1k-30. Furthermore, the controller 1k-50 records data in or reads data from the storage unit 1k-40. For this purpose, the controller 1k-50 may include at least one processor. For example, the controller 1k-50 may include a multi-connectivity processor 1k-52.

[0193] <Second Embodiment>

[0194] Figure 2A This is a diagram illustrating the structure of an LTE system for reference according to an embodiment of the present disclosure.

[0195] Reference Figure 2A The wireless communication system consists of several base stations 2a-05, 2a-10, 2a-15 and 2a-20, MME 2a-25 and service gateway (S-GW) 2a-30. The UE or "terminal" 2a-35 connects to the external network through base stations 2a-05, 2a-10, 2a-15 and 2a-20 and S-GW 2a-30.

[0196] Base stations 2a-05, 2a-10, 2a-15, and 2a-20 are connection nodes in the cellular network, providing radio connections to terminals connected to the network. Specifically, to provide services to users, base stations 2a-05, 2a-10, 2a-15, and 2a-20 perform scheduling by merging terminal state information (such as buffer state, available transmit power state, and channel state) to support the connection between the terminal and the CN. MME 2a-25 is responsible not only for terminal mobility management but also for various types of control functions. The MME connects to multiple base stations, and S-GW 2a-30 is the device that provides data bearers. Furthermore, MME 2a-25 and S-GW 2a-30 can further perform authentication and bearer management for terminals connected to the network, and process packets arriving from and destined for base stations 2a-05, 2a-10, 2a-15, and 2a-20.

[0197] Figure 2B This is a diagram illustrating the radio protocol structure of an LTE system according to an embodiment of the present disclosure. The radio protocol structure in the drawings may differ in part from the radio protocol structure of NR, which will be defined thereafter, but for convenience, it will be explained in the context of this disclosure.

[0198] Reference Figure 2B In a terminal or ENB, the radio protocol of an LTE system consists of PDCP 2b-05 or 2b-40, Radio Link Control (RLC) 2b-10 or 2b-35, and MAC 2b-15 or 2b-30. PDCP 2b-05 or 2b-40 is responsible for IP header compression / decompression operations, and RLC 2b-10 or 2b-35 reconfigures PDCP Packet Data Units (PDUs) to appropriate sizes. MAC 2b-15 or 2b-30 connects to various RLC layer devices configured in a terminal and performs multiplexing of RLC PDUs to MAC PDUs and demultiplexing of RLC PDUs from MAC PDUs. Physical layer 2b-20 or 2b-25 performs channel coding and modulation of higher-layer data and generates OFDM symbols for transmission over radio channels, or performs demodulation and decoding of OFDM symbols received over radio channels to transmit the demodulated and decoded OFDM symbols to higher layers. In addition, the PHY uses Hybrid Automatic Repeat Request (HARQ) for extra error correction, and the receiver uses one bit to indicate whether it accepts a packet sent from the sender. This is called the HARQ ACK / Negative Acknowledgment (NACK) message.

[0199] Downlink HARQ ACK / NACK information for uplink transmissions can be sent via the Physical Hybrid ARQ Indicator Channel (PHICH), and uplink HARQ ACK / NACK information for downlink transmissions can be sent via the PUCCH or the Physical Uplink Shared Channel (PUSCH).

[0200] Although not shown in the accompanying drawings, a Radio Resource Control (RRC) layer exists at a higher level than the PDCP layer of the terminal and base station. This RRC layer can send and receive connection and measurement-related configuration control messages. For example, the base station can use RRC layer messages to instruct the terminal to perform measurements, and the terminal can use RRC messages to report the measurement results to the base station.

[0201] Figure 2C This is a diagram illustrating the frame structure used in a 5G system applying the present disclosure according to an embodiment of the present disclosure.

[0202] Reference Figure 2C The following solutions could be considered: 5G systems operate at high frequencies to ensure sufficient bandwidth for higher transmission speeds. However, since transmitting signals at high frequencies is difficult, a solution using beamforming to send data could be considered.

[0203] Accordingly, the following scheme can be considered: the base station or TRP 2c-01 uses different beams to communicate with terminals 2c-71, 2c-73, 2c-75, 2c-77, and 2c-79 in the cell. That is, in Figure 2C In the example, it is assumed that terminal 2c-71 uses beam #1 2c-51 to perform communication, terminal 2c-73 uses beam #5 2c-55 to perform communication, and terminals 3, 4 and 5 perform communication through beam #7 2c-57.

[0204] To measure which beam the terminal uses to communicate with the TRP, OSF 2c-03 exists in time, and in OSF, the base station uses different beams to transmit RS according to symbols (or through several symbols). Figure 2C In this embodiment, it is assumed that the base station transmits 12 beams—beams #1 2c-51 to #12 2c-62—and that in the OSF, different beams are scanned and transmitted for each symbol 2c-31 to 2c-42. That is, in the OSF, each beam is transmitted according to symbol (e.g., beam #1 2c-51 is transmitted in the first symbol 2c-31), and the terminal can measure which beam signal transmitted in the OSF is the strongest by measuring the OSF. In embodiments of this disclosure, the beam that is constantly transmitted in the OSF as described above is called the common beam.

[0205] exist Figure 2C In this context, it is assumed that the corresponding OSF scheme is repeated for 25 subframes, and the remaining 24 subframes are DSF 2c-05 for transmitting and receiving ordinary data.

[0206] Accordingly, assume the following scheme: According to the base station's scheduling, terminals 2c-75, 2c-77 and 2c-79 jointly use beam #7 2c-11 to perform communication, terminal 2c-71 uses beam #1 2c-13 to perform communication, and terminal 2c-73 uses beam #5 2c-15 to perform communication.

[0207] Furthermore, since the beams used in the DSF are the same beams used by the terminals connecting to the base station, data can be transmitted and received by finer-tuning the direction based on the terminal's location. To this end, the terminal can report the strength / quality of the signals transmitted from each beam, allowing the base station to perform additional adjustments. The series of processes described above for fine-tuning is called a beam refinement process. Through the beam refinement process, the base station can use a more optimal beam to transmit and receive data along a direction different from the beam transmitted from the OSF, using a different beam. In embodiments of this disclosure, the beam designated for the terminal through the beam refinement process is called a dedicated beam. It is assumed that the dedicated beam can only be used in the connection modes described later.

[0208] In the exemplary figures, although the base station's transmit beams #1 2c-51 to #12 2c-62 are shown, the receive beams of the terminals used to receive the base station's transmit beams (e.g., beams 2c-81, 2c-83, 2c-85, and 2c-87 of terminal 2c-71) can also be considered. In the exemplary figures, terminal 1 has four beams 2c-81, 2c-83, 2c-85, and 2c-87, and it performs beam scanning to determine which beam has the best reception performance. In this case, if several beams cannot be used simultaneously, the optimal transmit beam of the base station and the receive beam of the terminal can be found by using one receive beam for each OSF and receiving from several OSFs as many as the number of receive beams.

[0209] Figure 2D This is a diagram illustrating the message flow between a terminal and a base station when using a method for selectively determining the beam to be measured according to the measurement configuration presented in embodiments of this disclosure.

[0210] Reference Figure 2DIn operation 2d-11, terminal 2d-01, in idle mode RRC_IDLE, camps at the corresponding base station to find a suitable cell, and then in operation 2d-13, a connection to the base station is established due to the generation of data to be transmitted. In idle mode, terminal 2d-01 does not connect to the network to conserve energy, and therefore cannot transmit data. For data transmission, terminal 2d-01 needs to switch to connected mode RRC_CONNECTED. Furthermore, as mentioned above, the term "camping" means that terminal 2d-01 remains in the corresponding cell and receives paging messages to determine whether data is being transmitted in the downlink. If terminal 2d-01 successfully connects to base station 2d-03, the state of terminal 2d-01 switches to connected mode RRC_CONNECTED, and terminal 2d-01 in connected mode can send data to / receive data from the base station.

[0211] Subsequently, when terminal 2d-01 in connected mode moves into or out of a cell, it is necessary to command the terminal's movement so that the terminal can perform transmission / reception through another beam or cell / base station. For this purpose, in operation 2d-15, base station 2d-03 is configured to instruct the terminal to measure the serving beam, adjacent beams within the same cell and the same Transmit & Receive Point (TRP), or adjacent beams between different TRPs within the same cell or another cell. The aforementioned measurement instruction includes one of the following conditions: if the following condition is met, terminal 2d-01 reports the measurement result to base station 2d-03.

[0212] —Event 1: The service beam becomes better than the predetermined threshold in terms of signal strength / quality.

[0213] —Event 2: The service beam becomes worse than a predetermined threshold in terms of signal strength / quality.

[0214] —Event 3: The signal strength / quality of adjacent beams between TRPs becomes biased towards the best beam within the TRP.

[0215] —Event 4: The case where adjacent beams between TRPs become better than a predetermined threshold in terms of signal strength / quality.

[0216] —Event 5: The serving beam becomes worse than threshold 1 in terms of signal strength / quality, and the adjacent beams between TRPs become better than threshold 2 in terms of signal strength / quality.

[0217] In operation 2d-17, terminal 2d-01, having received the configuration information as described above, will send an acknowledgment message indicating that the configuration information has been successfully received to base station 2d-03. Therefore, in LTE, an RRC connection reconfiguration completion message can be used.

[0218] As referenced above Figure 2C If terminal 2d-01 is in connected mode to perform data transmission / reception, it can use a dedicated beam in addition to the common beam. In embodiments of this disclosure, if terminal 2d-01 is configured according to one of the events described above, then during operation 2d-19, terminal 2d-01 can determine which beam is selected for measurement. That is, the dedicated beam can be measured based on the event, or the common beam can be measured even if the dedicated beam is used. The common beam may correspond to an SS block, and the dedicated block may correspond to CSI-RS. Measurements of the common beam can be based on the SS block, and measurements of the dedicated beam can be for CSI-RS.

[0219] More specifically, if in events 1 and 2, terminal 2d-01 measures only the signal strength / quality of the serving beam, then terminal 2d-01 measures the common beam if it performs communication using the common beam, and uses the dedicated beam if it uses the dedicated beam through the beam selection process.

[0220] Furthermore, if, in Event 3, Terminal 2d-01 compares the serving beam with adjacent beams in terms of signal strength / quality, then even if Terminal 2d-01 uses a dedicated beam as the serving beam, Terminal 2d-01 can still perform measurements using the common beam. This achieves a fair comparison between the serving beam and adjacent beams because the common beam is used to measure adjacent beams that do not have a dedicated beam.

[0221] Furthermore, even in Event 5, where Terminal 2d-01 compares the serving beam with a predetermined threshold 1 and the adjacent beam with a predetermined threshold 2, and sends a report when both conditions are met, in the same manner as in Event 3, Terminal 2d-01 uses the common beam to perform the measurement, even when Terminal 2d-01 uses the dedicated beam as the serving beam.

[0222] If, in event 4, terminal 2d-01 only measures the signal strength / quality of adjacent beams, then because there is no dedicated beam for the corresponding adjacent beams, terminal 2d-01 uses the common beam of the corresponding adjacent beams to perform the measurement.

[0223] Terminal 2d-01 can predefine for what events terminal 2d-01 will compare the serving beam with the common beam, and base station 2d-03 can configure the above using messages such as RRC messages or MAC messages.

[0224] As described above, in operation 2d-21, terminal 2d-01 selects the beam to be measured (i.e., common beam 2d-23, common beam 2d-25 of another base station 2d-05, or dedicated beam 2d-27 even if it is in the serving beam) based on the measurement event configured from base station 2d-03 to measure the corresponding beam. If it matches the measurement reporting conditions, in operation 2d-31, terminal 2d-01 reports the measurement result to base station 2d-03. Based on the measurement result, base station 2d-03 can send a command to move terminal 2d-01 to another beam in the same TRP within the same cell, to another beam in a different TRP within the same cell, or to a beam belonging to a TRP of another cell. In embodiments of this disclosure, it is assumed that terminal 2d-01 can determine the cell, the TRP within the cell, and the beam identifier from the common beams sent by each TRP.

[0225] Figure 2E This is a diagram illustrating the sequence of operations of a terminal according to an embodiment of the present disclosure.

[0226] Reference Figure 2E In the accompanying drawings, in operation 2e-03, it is assumed that a terminal in connection mode is connected to a base station / cell to send data to / receive data from the beam of the corresponding cell.

[0227] As described above, for mobility management, in Operation 2e-05, a terminal in a connected state is instructed by the base station to perform measurement configuration. The measurement configuration instruction message may include one or more of the following events, and if the following conditions are met, the terminal reports the measurement results to the base station.

[0228] —Event 1: The service beam becomes better than the predetermined threshold in terms of signal strength / quality.

[0229] —Event 2: The service beam becomes worse than a predetermined threshold in terms of signal strength / quality.

[0230] —Event 3: The adjacent beams between TRPs become biased towards better signal strength / quality than the best beam within the TRP.

[0231] —Event 4: The case where adjacent beams between TRPs become better than a predetermined threshold in terms of signal strength / quality.

[0232] —Event 5: The serving beam becomes worse than threshold 1 in terms of signal strength / quality, and the adjacent beams between TRPs become better than threshold 2 in terms of signal strength / quality.

[0233] In operation 2e-07, the terminal that has received the measurement configuration determines which event is the configured measurement event.

[0234] If, as in Event 1 or 2, the configured measurement event compares the serving beam to a predetermined threshold in terms of signal strength / quality, then in operation 2e-09, the terminal determines whether it is currently communicating with the serving cell using a common beam or using a dedicated beam through a beam selection process. If the terminal is currently communicating with the serving cell using a common beam, then in operation 2e-11, the terminal performs the measurement using the common beam when performing the measurement according to the event. If the terminal is currently communicating with the serving cell using a dedicated beam through a beam selection process, then in operation 2e-13, the terminal performs the measurement using the dedicated beam when performing the measurement according to the event. (Refer to the above.) Figure 2C The common beam is a beam that scans in all directions even in subframes such as OSF. Furthermore, a dedicated beam is characterized as having a different orientation and / or beamwidth than the common beam, and a terminal in a connected state is characterized as sending a dedicated message indicating which beam will be used through the beam selection process. Accordingly, in operation 2e-21, the terminal determines whether to perform a measurement report by measuring the signal strength / quality for the selected serving beam.

[0235] If, as in Event 3, the configured measurement event compares the serving beam with adjacent beams in terms of signal strength / quality, then in Operation 2e-15, the terminal performs measurements using the common beam even when communicating with the serving cell using a dedicated beam through a beam selection process. Adjacent beams can be beams from another TRP (inter-TRP within the same cell) or another TRP (inter-TRP between two cells) in another cell. Accordingly, it is assumed that each beam includes a cell identifier and a TRP identifier. Accordingly, if the adjacent beam refers to a beam from another TRP (inter-TRP within the same cell), it indicates that the TRP identifier becomes different; and if the adjacent beam refers to a beam from another TRP (inter-TRP between two cells) in another cell, it indicates that the cell identifier becomes different. Accordingly, in Operation 2e-23, the terminal selects a common beam for the serving beam and determines whether to perform a measurement report by measuring signal strength / quality for both the serving beam and adjacent beams.

[0236] If, as in Event 5, the configured measurement event compares the serving beam to a predetermined threshold in terms of signal strength / quality and the adjacent beam to a predetermined threshold in terms of signal strength / quality, then in Operation 2e-17, even when communicating with the serving cell using a dedicated beam through a beam selection process, the terminal uses a common beam to perform measurements. The adjacent beam can be a beam from another TRP (inter-TRP within the same cell) or a beam from another TRP (inter-TRP between two cells) in another cell. Accordingly, it is assumed that each beam includes a cell identifier and a TRP identifier. Accordingly, if the adjacent beam refers to a beam from another TRP (inter-TRP within the same cell), it indicates that the TRP identifier becomes different; and if the adjacent beam refers to a beam from another TRP (inter-TRP between two cells) in another cell, it indicates that the cell identifier becomes different. Accordingly, in Operation 2e-23, the terminal selects a common beam for the serving beam and determines whether to perform a measurement report by measuring signal strength / quality for both the serving beam and the adjacent beam.

[0237] If, in operation 2e-25, it is determined that the measurement results are sent according to the determination described above, then in operation 2e-27, the terminal reports the measurement results to the base station. Based on the measurement report, the base station can send commands to move the terminal to another beam within the same TRP in the same cell, to another beam within a different TRP in the same cell, or to a beam belonging to a TRP in a different cell.

[0238] Figure 2F This is a block diagram illustrating the configuration of a terminal according to an embodiment of the present disclosure.

[0239] Reference Figure 2F The terminal includes an RF processor 2f-10, a baseband processor 2f-20, a storage unit 2f-30, and a controller 2f-40.

[0240] The RF processor 2f-10 performs functions for transmitting and receiving signals via a radio channel (such as signal band conversion and amplification). Specifically, the RF processor 2f-10 performs up-conversion of baseband signals provided by the baseband processor 2f-20 to RF band signals for transmission to the antenna, and down-conversion of RF band signals received by the antenna back to baseband signals. For example, the RF processor 2f-10 may include transmit filters, receive filters, amplifiers, mixers, oscillators, DACs, and ADCs. Although in Figure 2F Only one antenna is shown, but the terminal can be equipped with multiple antennas. Furthermore, the RF processor 2f-10 can include multiple RF chains. Additionally, the RF processor 2f-10 can perform beamforming. For beamforming, the RF processor 2f-10 can adjust the phase and magnitude of signals transmitted or received through multiple antennas or wire elements.

[0241] The baseband processor 2f-20 performs the conversion between baseband signals and bit strings according to the system's PHY standard. For example, during data transmission, the baseband processor 2f-20 generates complex symbols by encoding and modulating the transmitted bit string. Furthermore, during data reception, the baseband processor 2f-20 recovers the received bit string by demodulating and decoding the baseband signal provided from the RF processor 2f-10. For example, following the OFDM method, during data transmission, the baseband processor 2f-20 generates complex symbols by encoding and modulating the transmitted bit string, performs mapping of the complex symbols to subcarriers, and then configures the OFDM symbols through IFFT operations and CP insertion. Furthermore, during data reception, the baseband processor 2f-20 divides the baseband signal provided from the RF processor 2f-10 into units of OFDM symbols, recovers the signal mapped to the subcarriers through FFT operations, and then recovers the received bit string through demodulation and decoding.

[0242] The baseband processor 2f-20 and RF processor 2f-10 can transmit and receive signals as described above. Therefore, the baseband processor 2f-20 and RF processor 2f-10 can be referred to as a transmitter, receiver, transceiver, or communication unit. Furthermore, to handle signals from different frequency bands, at least one of the baseband processor 2f-20 and RF processor 2f-10 may include different communication modules. Moreover, the different frequency bands may include the SHF (e.g., 2.5 GHz or 5 GHz) band and the millimeter wave (mmWave) (e.g., 60 GHz, etc.) band.

[0243] Storage unit 2f-30 can store data such as basic programs, applications and configuration information for the operation of the terminal.

[0244] Controller 2f-40 controls the overall operation of the terminal. For example, controller 2f-40 transmits and receives signals via baseband processor 2f-20 and RF processor 2f-10. Furthermore, controller 2f-40 records data in or reads data from storage unit 2f-30. For this purpose, controller 2f-40 may include at least one processor. For example, controller 2f-40 may include a CP that performs control for communication and a higher-level AP that controls applications such as applications. In embodiments of this disclosure, controller 2f-40 includes a multi-connection processor 2f-42. For example, controller 2f-40 may control the terminal to perform actions such as... Figure 2F The process of operating the terminal is shown in the figure.

[0245] In embodiments of this disclosure, after connecting to a base station, the terminal receives a message from the base station commanding a measurement. The controller, having received the message, determines whether a condition for sending a measurement report to the base station is met by measuring the beam to be measured according to a measurement event configured from the base station. If the condition is met, the controller generates a message including the measurement result and sends the generated message to the base station via the base station processor and the RF processor.

[0246] <Third Embodiment>

[0247] Figure 3A This is a diagram illustrating a multi-connectivity operation scheme in a next-generation mobile communication system according to embodiments of the present disclosure.

[0248] Reference Figure 3A The radio access network of the next-generation mobile communication system consists of NR NB 3a-15 and NR CN 3a-05. The user terminal (NR UE) 3a-20 connects to the external network through NR NB 3a-15 and NR CN 3a-05.

[0249] Reference Figure 3A The NR NB 3a-15 corresponds to the eNB in ​​the existing LTE system. The NR NB connects to the NB UE 3a-20 via radio channels, thereby providing superior service compared to existing Node Bs. Since all user traffic is served through a shared channel, it is necessary to perform scheduling by combining the state information of each UE (such as buffer state, available transmit power state, and channel state), and the NR NB 3a-15 is responsible for this process. An NR NB typically controls multiple cells. To achieve ultra-high data transmission speeds compared to existing LTE, the NR NB may have a bandwidth equal to or greater than the existing maximum bandwidth, and OFDM can be considered in conjunction with beamforming technology as a radio connection technology. Furthermore, the AMC method, which determines the modulation scheme and channel coding rate to match the terminal's channel state, is applied to the NR NB. The NR NB 3a-15 performs mobility support, bearer configuration, and QoS configuration. The NR CN is responsible not only for terminal mobility management but also for various types of control functions and connects to multiple base stations. Furthermore, the next-generation mobile communication system can be interlocked with the existing LTE system, and the NR CN connects to the MME 3a-25 via a network interface. The MME connects to the eNB 3a-25, which serves as an existing base station. Terminals can simultaneously connect to both the NR NB and the eNB to receive services. This is referred to as multi-connectivity. Multi-connectivity is defined as follows.

[0250] An operating mode in which multiple Rx / Tx UEs in connected mode are configured to use radio resources in E-UTRA and / or NR provided by multiple independent schedulers via non-ideal backhaul connections.

[0251] As an example of a service solution, multi-connected terminals can receive ultra-high-speed data transmission services via NR and VoLTE (voice) services via LTE.

[0252] Figure 3B This is an illustration explaining a terminal having multiple RF chains for supporting multiple connections according to an embodiment of the present disclosure. Multiple RF chains are necessary to support multiple connections.

[0253] Reference Figure 3B The terminal has one RF chain consisting of RX chain 3b-05 and TX chain 3b-10 supporting NR, and another RF chain consisting of RX chain 3b-15 and TX chain 3b-20 supporting LTE. Terminals with multiple RF chains can simultaneously perform data transmission / reception with both NR and LTE. However, this architecture increases the terminal's power consumption due to the large number of RF chains and offers no savings in material costs. In the case of inexpensive terminals, this increased cost makes multi-connectivity support impractical. Furthermore, intra-device interference occurs between the RX and TX chains. This is known as intra-device coexistence (IDC) interference. For example, a signal radiated from the TX chain can be input into the NR RX chain, becoming an interference signal for NR.

[0254] Figure 3C This is a diagram illustrating the application of TDM methods used to support multiple connections.

[0255] Reference Figure 3C One method to overcome the drawbacks of multiple connections using multiple RF chains as described above is the application of the Time-Distribution Model (TDM) method, which allows data transmission / reception to be performed using only one system at a time when a single RF chain is being used. A single RF chain implies reduced power consumption and material costs in the terminal. Furthermore, IDC interference can be eliminated according to the TDM method. For example, in the case of using NR at frequency F1 and LTE at frequency F2, the terminal can transmit / receive data to / from NR in a specific time period t1 3c-05, and can transmit / receive data to / from LTE in a specific time period t3 3c-15 after a predetermined RF transition time t2 3c-10. A predetermined time is required for a single RF chain to control a predetermined frequency band. Accordingly, data transmission / reception is not performed during the aforementioned time periods.

[0256] Figure 3D This is a diagram illustrating a terminal having a single RF chain for applying a TDM method according to an embodiment of the present disclosure.

[0257] Reference Figure 3D The terminal has a single RF chain consisting of an RX chain 3d-05 and a TX chain 3d-10. For a specific time period, the terminal's RF chain is configured to use frequencies used only by NR or LTE. Furthermore, for a specific time period, the RX chain can be configured to NR frequencies (LTE frequencies), and the TX chain can be configured to LTE frequencies (NR frequencies).

[0258] Figure 3E This is a diagram illustrating a terminal having a single TX chain and multiple RX chains for applying the TDM method, according to an embodiment of the present disclosure.

[0259] Reference Figure 3E The terminal has multiple RX chains 3e-05 and 3e-10 and one TX chain 3e-15. The terminal can receive data from both NR and LTE simultaneously, but can only send data to either NR or LTE for a given time period. This architecture is less efficient in terms of power consumption and cost, but has advantages in terms of complexity.

[0260] Figure 3F This is a diagram illustrating the third-1st embodiment of configuring TDM type multiple connections according to embodiments of the present disclosure.

[0261] Reference Figure 3F Terminal 3f-05 resides on the first base station 3f-10. In this case, the first base station 3f-10 acts as the host triggering TDM operation. The first base station 3f-10 can be an NR NB or an eNB. In operation 3f-20, the first base station 3f-10 notifies the terminal 3f-05 whether it supports TDM operation. In operation 3f-30, the terminal 3f-05 notifies the first base station 3f-10 whether it supports TDM operation. In operation 3f-25, the second base station 3f-15 notifies the first base station 3f-10 whether it supports TDM operation. In operation 3f-35, the first base station 3f-10 determines whether to configure TDM operation based on the service or QoS provided to the terminal 3f-05. Furthermore, the terminal 3f-05 determines whether TDM operation is necessary based on the service or QoS to be provided to itself, and may request the first base station to provide TDM operation in operation 3f-40.

[0262] If TDM operation is configured based on a decision by the first base station 3f-10 or a terminal request, then in operation 3f-45, the first base station 3f-10 provides configuration information related to the TDM operation to the terminal 3f-05. The configuration information includes at least information about the TDM pattern. The TDM pattern is time information about when the terminal 3f-05 can transmit / receive data on NR or LTE frequencies. This information can be provided in bitmap form, or it can be provided as time period information, period, and offset information for staying at a specific frequency. If the information is provided in bitmap form, each bit is used to indicate the frequency at which the terminal 3f-05 transmits / receives data for a specific unit of time. The specific unit of time can be configured. If the information is provided as time period information, period, and offset information for staying at a specific frequency, the offset information is used to calculate the time point at which data will be transmitted or received at the specific frequency, and the time period information for staying at the specific frequency is used to transmit or receive data at the indicated time period for that frequency. The time period carries a specific period. During operation 3f-50, terminal 3f-05, having received TDM configuration information, operates a specific timer. Until this specific timer expires, the terminal should complete the RRC connection establishment with the second base station 3f-15.

[0263] During the specific timer operation period, in operation 3f-55, the terminal's RF chain should be configured to the frequency used by the second base station 3f-15. During this time period, terminal 3f-05 receives system information from the second base station 3f-15 in operation 3f-60 and performs random access in operation 3f-65. Furthermore, during this time period, the terminal provides TDM configuration information from the first base station 3f-10 to the second base station 3f-15. If the RRC connection with the second base station 3f-15 is successfully established, terminal 3f-15 begins TDM operation at the specific time in operation 3f-70. If the RRC connection establishment fails to complete successfully before the timer expires, terminal 3f-05 cannot begin TDM operation in operation 3f-75, and in this case, terminal 3f-05 notifies the first base station 3f-10 of this failure using a specific message in operation 3f-80. The specific time at which TDM operation begins should be known to terminal 3f-05, the first base station 3f-10, and the second base station 3f-15. Accordingly, a method for indicating this information is necessary.

[0264] —Method 1: A method in which terminal 3f-05 notifies NR or LTE of the start time of TDM operation using a specific message from operation 3f-80. If the RRC connection with the second base station 3f-15 is established, terminal 3f-05 notifies the first base station of the time using L1 signaling, MAC CE, or RRC messages. The second base station 3f-15 may implicitly know the TDM operation time based on random access performance. Alternatively, like the first base station 3f-10, terminal 3f-05 may notify the first base station of the time using L1 signaling, MAC CE, or RRC messages.

[0265] —Method 2: A method for the first base station 3f-10 to implicitly initiate TDM operation. The first base station 3f-10 initiates TDM operation using a custom timer without receiving any messages from the terminal 3f-05. The timer starts after the TDM configuration information is provided to the terminal 3f-05 and may have the same or similar configuration value as the timer. The second base station 3f-15 may also implicitly determine the TDM operation time based on random access performance.

[0266] If TDM operation begins, then in operations 3f-85 and 3f-90, terminal 3f-05 uses TDM mode information to perform data transmission / reception by switching between NR and LTE frequencies.

[0267] Figure 3G This is a diagram illustrating the operation of a terminal according to a first embodiment of the present disclosure.

[0268] Reference Figure 3G In operation 3g-05, the terminal exchanges TDM support capabilities with the first base station on which it is camped. In operation 3g-10, the terminal requests TDM operation from the first base station based on the type or QoS of the service to be provided to the terminal. In operation 3g-15, the terminal receives TDM configuration information from the first base station. The configuration information includes TDM mode information. In operation 3g-20, the terminal receives system information from the second base station, and in operation 3g-30, the terminal performs random access processing. In operation 3g-35, the terminal sends all or part of the TDM configuration information provided by the first base station to the second base station. The sent configuration information includes at least TDM mode information. In operation 3g-40, the terminal performs TDM operation with the first and second base stations at a specific time.

[0269] Figure 3H This is a diagram illustrating the operation of a first base station according to a first embodiment of the present disclosure.

[0270] Reference Figure 3HDuring operation 3h-05, the first base station exchanges TDM support capabilities with the terminal. During operation 3h-10, the first base station determines the TDM operation based on the type or QoS of the service to be provided to the terminal and the service provider / network policy. During operation 3h-15, the first base station sends TDM configuration information to the terminal. During operation 3h-20, the first base station performs TDM operations with the terminal at specific times.

[0271] Figure 3I This is a diagram illustrating a second embodiment for configuring TDM type multiple connections according to embodiments of the present disclosure.

[0272] Reference Figure 3ITerminal 3i-05 resides on the first base station 3i-10. In this configuration, the first base station acts as the host triggering TDM operations. The first base station can be an NR NB or an eNB. In operation 3i-20, the first base station 3i-10 notifies terminal 3i-05 whether it supports TDM operations. In operation 3i-30, terminal 3i-05 notifies the first base station 3i-10 whether it supports TDM operations. In operation 3i-25, the second base station 3i-15 notifies the first base station 3i-10 whether it supports TDM operations. In operation 3i-35, the first base station 3i-10 determines whether to configure TDM operations based on the service or QoS provided to terminal 3i-05. Furthermore, the terminal determines whether TDM operations are necessary based on the service or QoS to be provided to terminal 3i-05 and may request the first base station 3i-10 to provide TDM operations in operation 3i-40. If TDM operation is configured based on a decision by the first base station 3i-10 or a terminal request, then in operation 3i-45, the first base station 3i-10 requests the second base station 3i-15 to provide TDM operation using a message including configuration information related to the TDM operation. In operation 3i-50, the second base station 3i-15 sends a response message to the first base station 3i-10. In operation 3i-55, the first base station 3i-10, having received the acceptance response message from the second base station 3i-15, provides the terminal 3i-05 with the configuration information related to the TDM operation. The configuration information includes at least TDM mode information. The TDM mode is the time information at which the terminal 3i-05 can transmit / receive data on NR or LTE frequencies. This information can be provided in bitmap form, or it can be provided as time period information, period, and offset information for staying at a specific frequency. If the information is provided in bitmap form, each bit is used to indicate the frequency at which the terminal 3i-05 transmits / receives data for a specific unit of time. This specific unit of time can be configured. If the information is provided as time period information, period, and offset information for staying at a specific frequency, the offset information is used to calculate the time point at which data will be transmitted or received at the specific frequency, and the time period information for staying at the specific frequency is used to transmit or receive data at that frequency for the indicated time period. The time period carries the specific period. In operation 3i-60, terminal 3i-05, having received TDM configuration information, operates a specific timer. Until the specific timer expires, terminal 3i-05 should complete the connection with the second base station. During the operation of the specific timer, in operation 3i-70, the RF chain of terminal 3i-05 should be configured to the frequency used by the second base station 3i-15. During the time period, terminal 3i-05 receives system information from the second base station 3i-15 in operation 3i-65 and performs random access processing in operation 3i-75.System information of the second base station 3i-15 can be transmitted to terminal 3i-05 via an RRC connection configuration message in operation 3i-55. When operating 3i-50 receives a TDM response from the second base station 3i-15, the first base station 3i-10 can simultaneously be provided with the system information of the second base station 3i-15. Furthermore, during the time period, in operation 3i-80, terminal 3i-05 provides the TDM configuration information provided by the first base station 3i-10 to the second base station 3i-15. If the second base station 3i-15 successfully receives an RRC connection identification completion message from terminal 3i-05, the connection to the second base station 3i-15 is completed, and TDM operation begins at a specific time. If the connection is not successfully completed before the timer expires, in operation 3i-85, terminal 3i-05 cannot begin TDM operation, and in this case, in operation 3i-90, terminal 3i-05 notifies the first base station 3i-10 of this failure using a specific message. The specific time at which TDM operation begins should be known to terminal 3i-05, the first base station 3i-10, and the second base station 3i-15. Methods for indicating this information have already been described.

[0273] If TDM operation begins, then in operations 3i-95 and 3i-100, terminal 3i-05 uses TDM mode information to perform data transmission / reception by switching between NR and LTE frequencies.

[0274] exist Figure 3D In the illustrated configuration, terminal 3i-05 can perform TDM operations for both downlink and uplink. Figure 3E In the configuration shown, terminal 3i-05 can perform TDM operations when transmitting uplink signals and data for the uplink.

[0275] Terminal 3i-05 can be dually linked to the first base station 3i-10 and the second base station 3i-15, and when the first base station 3i-10 is an LTE base station and the second base station 3i-15 is an NR base station, it can correspond to EN-DC.

[0276] Figure 3J This is a diagram illustrating the operation of a first base station according to the third-second embodiment of this disclosure.

[0277] Reference Figure 3JIn operation 3j-05, the first base station exchanges TDM support capabilities with the terminal. In operation 3j-10, the first base station determines the TDM operation based on the type or QoS of the service to be provided to the terminal and the service provider / network policy. In operation 3j-15, the first base station requests the second base station to provide TDM operation. In operation 3j-20, the first base station receives an acceptance response message from the second base station. In operation 3j-25, the first base station sends TDM configuration information to the terminal. In operation 3j-30, the first base station performs TDM operation with the terminal at a specific time.

[0278] Figure 3K This is a diagram illustrating a scheme for explaining a method for releasing a TDM according to an embodiment of the present disclosure.

[0279] Reference Figure 3K If a specific event occurs, the terminal performing TDM operation can suspend it. In embodiments of this disclosure, if emergency disaster information (such as Earthquake and Tsunami System (ETWS) / Commercial Mobile Alarm System (CMAS)) is sent, the ongoing TDM operation is suspended or released during operation 3k-15, and the emergency disaster information is preferably received from the system providing ETWS / CMAS. Generally, given the importance of the event, the terminal should complete the reception of emergency disaster information as quickly as possible. However, while maintaining TDM operation, it takes time to complete the reception of emergency disaster information. For example, if the emergency disaster information is only provided in the NR system, switching to the LTE system means that it will take a long time until the reception of the emergency disaster information is completed. Even when both NR and LTE systems provide emergency disaster information, the emergency disaster messages sent from the respective systems have different formats; therefore, considering the time delay, it is beneficial to receive the emergency disaster information only in the specific system. The terminal receives a paging message indicating that the emergency disaster message is being sent from the NR or LTE system. Terminals that have already received a paging message ignore the configured TDM operation and receive system information, including emergency disaster messages broadcast by the system that sent the paging message. The configured TDM operation is not executed until the emergency disaster message has been successfully received.

[0280] Furthermore, in embodiments of this disclosure, the terminal can suspend or release the configured TDM for a specific system under the following circumstances:

[0281] —The terminal performs the reconstruction, or

[0282] —Transfer, or

[0283] —If an RLF occurs.

[0284] If an RLF (Recurrent Link Fault) occurs, the terminal performs different actions depending on whether the base station where the RLF occurred is a master or slave. If the RLF occurs at the master base station, the terminal suspends or releases the TDM (Transmission Management) operation and performs a re-establishment operation. If the RLF occurs at the slave base station, the terminal can either perform a re-establishment operation or completely release the connection. In the case of performing a re-establishment operation, the operation is performed on the frequency of the system where the RLF occurred, and no TDM operation is performed during the re-establishment process. This is to maximize the success rate of re-establishment.

[0285] Even when a handover is performed, the RF chain is fixed to the frequency of the system that performed the handover. That is, TDM operations are suspended or released. This is also to maximize the success rate of the handover.

[0286] In embodiments of this disclosure, if the aforementioned reason occurs in the terminal performing TDM operation, the terminal may release or suspend the TDM operation, and such operation may be applied to all TDM operations transmitted via the uplink of the terminal and TDM operations received via the downlink of the terminal.

[0287] Figure 3L This is a block diagram illustrating the internal structure of a terminal according to an embodiment of the present disclosure.

[0288] Reference Figure 3L The terminal includes an RF processor 3l-10, a baseband processor 3l-20, a storage unit 3l-30, and a controller 3l-40.

[0289] RF processor 3l-10 performs functions for transmitting and receiving signals via a radio channel, such as signal band conversion and amplification. Specifically, RF processor 3l-10 performs up-conversion of baseband signals provided by baseband processor 3l-20 to RF band signals for transmission to the antenna, and down-conversion of RF band signals received by the antenna back to baseband signals. For example, RF processor 3l-10 may include transmit filters, receive filters, amplifiers, mixers, oscillators, DACs, and ADCs. Although only one antenna is shown in the figures, the terminal may have multiple antennas. Furthermore, RF processor 3l-10 may include multiple RF chains. Additionally, RF processor 3l-10 can perform beamforming. For beamforming, RF processor 3l-10 can adjust the phase and magnitude of signals transmitted or received through multiple antennas or wire elements. Furthermore, the RF processor can perform MIMO and can receive multiple layers during MIMO operation.

[0290] The baseband processor 3l-20 performs the conversion between baseband signals and bit strings according to the system's PHY standard. For example, during data transmission, the baseband processor 3l-20 generates complex symbols by encoding and modulating the transmitted bit string. Furthermore, during data reception, the baseband processor 3l-20 recovers the received bit string by demodulating and decoding the baseband signal provided from the RF processor 3l-10. For example, following the OFDM method, during data transmission, the baseband processor 3l-20 generates complex symbols by encoding and modulating the transmitted bit string, performs mapping of the complex symbols to subcarriers, and then configures the OFDM symbols through IFFT operations and CP insertion. Furthermore, during data reception, the baseband processor 3l-20 divides the baseband signal provided from the RF processor 3l-20 into units of OFDM symbols, recovers the signal mapped to the subcarriers through FFT operations, and then recovers the received bit string through demodulation and decoding.

[0291] The baseband processor 3l-20 and RF processor 3l-10 transmit and receive signals as described above. Therefore, the baseband processor 3l-20 and RF processor 3l-10 can be referred to as a transmitter, receiver, transceiver, or communication unit. Furthermore, to support different radio connectivity technologies, at least one of the baseband processor 3l-20 and RF processor 3l-10 may include multiple communication modules. Additionally, to process signals in different frequency bands, at least one of the baseband processor 3l-20 and RF processor 3l-10 may include different communication modules. For example, different radio connectivity technologies may include LTE networks and NR networks. Furthermore, different frequency bands may include super SHF (e.g., 2.5 GHz or 5 GHz) bands and millimeter wave (mmWave) (e.g., 60 GHz, etc.) bands.

[0292] Storage unit 31-30 can store data including basic programs, application programs, and configuration information for the operation of the terminal. Specifically, storage unit 31-30 can store information related to a second connection node performing wireless communication using a second radio connection technology. Furthermore, storage unit 31-30 provides stored data upon request from controller 31-40.

[0293] Controller 3l-40 controls the overall operation of the terminal. For example, controller 3l-40 transmits and receives signals via baseband processor 3l-20 and RF processor 3l-10. Furthermore, controller 3l-40 records data in or reads data from storage unit 3l-30. For this purpose, controller 3l-40 may include at least one processor. For example, controller 3l-40 may include a CP that performs control for communication and a higher-level AP that controls applications such as applications. Controller 3l-40 may include a multi-connection processor 3l-42.

[0294] Figure 3M This is a block diagram illustrating the configuration of a base station according to an embodiment of the present disclosure.

[0295] Reference Figure 3M The base station includes an RF processor 3m-10, a base station processor 3m-20, a backhaul communication unit 3m-30, a storage unit 3m-40, and a controller 3m-50.

[0296] The RF processor 3m-10 performs functions for transmitting and receiving signals via a radio channel, such as signal band conversion and amplification. Specifically, the RF processor 3m-10 performs up-conversion of baseband signals provided by the baseband processor 3m-20 to RF band signals for transmission to the antenna, and down-conversion of RF band signals received by the antenna back to baseband signals. For example, the RF processor 3m-10 may include transmit filters, receive filters, amplifiers, mixers, oscillators, DACs, and ADCs. Although only one antenna is shown in the figures, multiple antennas may be configured at the first connection node. Furthermore, the RF processor 3m-10 may include multiple RF chains. Additionally, the RF processor 3m-10 can perform beamforming. For beamforming, the RF processor 3m-10 can adjust the phase and magnitude of signals transmitted or received through multiple antennas or antenna elements. Furthermore, the RF processor can perform downlink MIMO operation by transmitting one or more layers.

[0297] The baseband processor 3m-20 performs the conversion between baseband signals and bit strings according to the PHY standard of the first radio connection technology. For example, during data transmission, the baseband processor 3m-20 generates complex symbols by encoding and modulating the transmitted bit string. Furthermore, during data reception, the baseband processor 3m-20 recovers the received bit string by demodulating and decoding the baseband signal provided from the RF processor 3m-10. For example, following the OFDM method, during data transmission, the baseband processor 3m-20 generates complex symbols by encoding and modulating the transmitted bit string, performs mapping of the complex symbols to subcarriers, and then configures the OFDM symbols through IFFT operations and CP insertion. Furthermore, during data reception, the baseband processor 3m-20 divides the baseband signal provided from the RF processor 3m-10 into units of OFDM symbols, recovers the signal mapped to the subcarriers through FFT operations, and then recovers the received bit string through demodulation and decoding. The baseband processor 3m-20 and the RF processor 3m-10 can transmit and receive signals as described above. Therefore, the baseband processor 3m-20 and the RF processor 3m-10 can be referred to as a transmitter, a receiver, a transceiver, or a communication unit.

[0298] The backhaul communication unit 3m-30 provides an interface for performing communication with other nodes in the network. That is, the backhaul communication unit 3m-30 converts bit strings sent from the main base station to another node, such as an auxiliary base station or CN, into physical signals, and converts physical signals received from said other node into bit strings.

[0299] Storage unit 3m-40 stores data containing basic procedures, application programs, and configuration information for the operation of the main base station. Specifically, storage unit 3m-40 can store information about bearers assigned to connected terminals and measurement results reported from connected terminals. Furthermore, storage unit 3m-40 can store information that determines whether to provide or suspend multiple connections to terminals. Additionally, storage unit 3m-40 provides stored data upon request from controller 3m-50.

[0300] The controller 3m-50 controls the overall operation of the main base station. For example, the controller 3m-50 transmits and receives signals via the baseband processor 3m-20 and the RF processor 3m-10, or via the backhaul communication unit 3m-30. Furthermore, the controller 3m-50 records data in or reads data from the storage unit 3m-40. For this purpose, the controller 3m-50 may include at least one processor. For example, the controller 3m-50 may include a multi-connectivity processor 3m-52.

[0301] <Fourth Embodiment>

[0302] Figure 4A This is a diagram illustrating the structure of a next-generation mobile communication according to an embodiment of the present disclosure.

[0303] Reference Figure 4A The radio access network of the next-generation mobile communication system consists of a new radio point node B (hereinafter referred to as "NR NB") 4a-10 and NR CN 4a-05. The user terminal ("NR UE" or "terminal") 4a-15 connects to the external network through NR NB 4a-10 and NR CN 4a-05.

[0304] exist Figure 4AIn this context, NR NB 4a-10 corresponds to the eNB in ​​the existing LTE system. The NR NB connects to NR UE 4a-15 via radio channels, thereby providing superior service compared to existing Node Bs. Since all user traffic is served through a shared channel, it is necessary to perform scheduling by merging state information such as buffer state, available transmit power state, and channel state for each UE; and NR NB 4a-10 is responsible for this process. An NR NB typically controls multiple cells. To achieve ultra-high data transmission speeds compared to existing LTE, the NR NB may have a bandwidth equal to or greater than the existing maximum bandwidth, and OFDM can be considered in conjunction with beamforming technology as a radio connection technology. Furthermore, the AMC method, which determines the modulation scheme and channel coding rate to match the terminal's channel state, is applied to the NR NB. NR CN4a-05 performs mobility support, bearer configuration, and QoS configuration. The NR CN is responsible not only for terminal mobility management but also for various types of control functions and connects to multiple base stations. Furthermore, the next-generation mobile communication system can be interlocked with the existing LTE system, and the NR CN is connected to the MME 4a-25 via a network interface. The MME is connected to the eNB 4a-30, which serves as an existing base station.

[0305] Figure 4B This is a diagram illustrating the frame structure used by an NR system applying the present disclosure according to an embodiment of the present disclosure.

[0306] Reference Figure 4B The following solutions could be considered: the NR system operates at high frequencies to ensure wide bandwidth for higher transmission speeds. However, since it is difficult to transmit signals at high frequencies, a solution using beamforming to transmit data could be considered.

[0307] Accordingly, the following scheme can be considered: the base station or TRP 4b-01 uses different beams to communicate with terminals 4b-71, 4b-73, 4b-75, 4b-77, and 4b-79 in the cell. That is, in Figure 4B In the example, it is assumed that terminal 4b-71 uses beam #1 4b-51 to perform communication, terminal 4b-73 uses beam #5 4b-55 to perform communication, and terminals 3, 4 and 5 perform communication through beam #7 4b-57.

[0308] To measure which beam the terminal uses to communicate with the TRP, OSF 4b-03 exists in time, and in OSF, the base station uses different beams to transmit RS according to symbols (or through several symbols). Beam index values ​​used to distinguish the individual beams from the RS can be derived. Figure 4BIn this scenario, assume the base station transmits 12 beams—beam #1 4b-51 to beam #12 4b-62—and in the OSF (Optical Storage Function), different beams are scanned and transmitted for each symbol 4b-31 to 4b-42. That is, in the OSF, each beam is transmitted according to symbol (e.g., beam #1 4b-51 is transmitted in the first symbol 4b-31), and the terminal can measure which beam signal transmitted in the OSF is the strongest by measuring the OSF.

[0309] exist Figure 4B In this context, it is assumed that the corresponding OSF scheme is repeated for 25 subframes, and the remaining 24 subframes are DSF 4b-05 for transmitting and receiving ordinary data.

[0310] Accordingly, assume the following scheme: According to the base station's scheduling, terminals 4b-75, 4b-77, and 4b-79 jointly use beam #7 4b-11 to perform communication, terminal 4b-71 uses beam #1 4b-13 to perform communication, and terminal 4b-73 uses beam #5 4b-15 to perform communication.

[0311] In the exemplary figures, although the base station's transmit beams #1 4b-51 to #12 4b-62 are shown, the receive beams of the terminals used to receive the base station's transmit beams (e.g., beams 4b-81, 4b-83, 4b-85, and 4b-87 of terminal 4b-71) can also be considered. In the exemplary figures, terminal 1 has four beams 4b-81, 4b-83, 4b-85, and 4b-87, which performs beam scanning to determine which beam has the best reception performance. In this case, if several beams cannot be used simultaneously, the optimal transmit beam of the base station and the receive beam of the terminal can be found by using one receive beam for each OSF and receiving from several OSFs as many as the number of receive beams.

[0312] Figure 4C This is a diagram illustrating radio link monitoring (RLM) operation in an LTE system according to embodiments of the present disclosure.

[0313] Reference Figure 4C The PHY 4c-10 measures downlink signal quality based on the Cell-Specific Reference Signal (CRS). Signal quality refers to Reference Signal Received Power (RSRP) or Reference Signal Received Quality (RSRQ). The measured value is compared to a specific threshold, Qout. This threshold is a signal quality value that satisfies a specific block error rate (BLER) for the PDCCH. If the measured value is not higher than the threshold, the PHY sends an "out-of-sync" indicator to the upper ("higher") layer 4c-05. The relationship between the threshold and BLER is affected by terminal performance and is therefore derived through terminal implementation.

[0314] Figure 4D This is a diagram illustrating radio link failure (RLF) operation in an LTE system according to embodiments of the present disclosure.

[0315] Reference Figure 4D The terminal's PHY compares the measured CRS signal quality with Qout in a specific period 4d-05. If the upper layer receives the "unsynchronized" indicator N310 several times from the physical layer, the T310 timer operates on 4d-20 in 4d-15. If the PHY N311 reports the "in-sync" indicator several times before the T310 timer expires, the T310 timer is suspended. Conversely, if the T310 timer expires, an RLF is declared on 4d-25. Afterward, the terminal initializes the re-establishment process and operates the T311 timer on 4d-30. If the terminal finds a suitable cell, it suspends the T311 timer on 4d-40 and operates the T301 timer. If the terminal receives an RRC connection re-establishment message from the base station, the T301 timer is suspended. If either the T311 or T301 timer expires, the terminal switches to standby mode on 4d-45. The values ​​of N300, N311, T310, T311, and T301 are provided from the network.

[0316] Figure 4E This is a diagram illustrating the conceptual explanation of RLF operation in a next-generation mobile communication system according to embodiments of the present disclosure.

[0317] Reference Figure 4E Even next-generation mobile communication systems can have RLF processing similar to existing LTE. Conceptually, if the downlink signal quality measured by the terminal is worse than a certain threshold in 4e-05, then Qout continues for a certain period of time in 4e-10, and RLF is declared in 4e-15. After the RLF is declared, a re-establishment process for connection restoration is performed in 4e-20. If the re-establishment process is not successfully executed, the terminal switches to standby mode in 4e-25.

[0318] Figure 4F This is a diagram illustrating the serving beams and beam groups under RLM / RLF in a next-generation mobile communication system according to embodiments of the present disclosure.

[0319] Reference Figure 4FA TRP 4f-01 consists of one or more beams 4f-51 to 4f-62. The downlink serving beam 4f-55 is the downlink beam of the TRP used when the TRP sends data to / receives data from the terminal. Typically, the beamwidth of the antenna is very narrow, and in the case of a moving terminal, the measured signal quality of the serving beam changes abruptly. Conversely, the serving beam can be easily changed to an adjacent beam under the same TRP. For RLM operation, only the RS provided by the serving beam can be measured and compared with a specific threshold Qout, but this is insufficient to declare an RLF. This is because the terminal can relatively easily restore the radio connection by sufficiently changing the serving beam to another beam under the same TRP. Accordingly, in the case of performing RLM operation, it is necessary to consider not only the signal quality of the serving beam but also the signal quality of adjacent beams under the same TRP.

[0320] In embodiments of this disclosure, the signal quality of a specific beamgroup 4f-63 within the same TRP is additionally considered during RLM operation. A beamgroup consists of all or part of the beams within the same TRP and can use various arrangement methods. For example, beams belonging to a beamgroup can be defined as:

[0321] —A beam capable of providing constant signal quality to the terminal within the same TRP.

[0322] —The beam adjacent to the terminal's current serving beam in the same TRP, or

[0323] —All beams in the same TRP.

[0324] In embodiments of this disclosure, the characteristic is that during RLM operation, the terminal considers not only the signal quality of the serving beam, but also the collective signal quality of a specific beamgroup within the same TRP. The collective signal quality of the beamgroup can be...

[0325] —The best signal quality among the beams in this group.

[0326] —The average signal quality of the n higher beams in this group.

[0327] —The sum of the signal quality of the beams belonging to this group.

[0328] —The average signal quality of the beams belonging to this group, or

[0329] —The weighted sum of the signal quality of the beam after predefined weights have been assigned to the signal quality.

[0330] If the signal quality of the serving beam is not good, but the collective signal quality of the beam group is above a certain threshold, then in addition to declaring an RLF, it is preferable to perform a radio link restoration operation to change the serving beam to another beam (a beam belonging to the same beam group) under the same TRP.

[0331] Figure 4G This is a diagram illustrating RLM operation according to an embodiment of the present disclosure.

[0332] Reference Figure 4G The PHY 4g-10 checks whether the signal quality of the serving beam and the collective signal quality of a specific beam group are better than different thresholds, respectively. The PHY periodically reports the results to the upper (“higher”) layer 4g-5. If the signal quality of the serving beam is below a first threshold Qout, and the collective signal quality of the specific beam group is above a second threshold Qout (beam group), the PHY reports a “Radio Link Recovery” indicator to the upper layer. If the upper layer receives the “Radio Link Recovery” indicator as a report first, a first timer operates, and if the first timer expires, the terminal performs a first process. During the first process, the terminal performs operations to change the serving beam to another beam in the same TRP. If, while the first timer is operating, the signal quality of the serving beam becomes better than the first threshold, or the signal quality of the specific beam group becomes below the second threshold, the first timer is suspended. If the signal quality of the serving beam is below the first threshold, and the collective signal quality of the specific beam group is below the second threshold, the PHY reports a “Radio Link Problem” indicator to the upper layer. The “Radio Link Problem” indicator corresponds to the “Unsynchronized” indicator in LTE. If the upper layer first receives the “Radio Link Problem” indicator as a report, a second timer operates, and if the second timer expires, the terminal declares an RLF. Terminals that have declared an RLF perform a second process. The second process represents the process of reporting the RLF to the network after establishing a connection to re-establish the connection. If, while the second timer is operating, the signal quality of the serving beam becomes better than a first threshold, or the signal quality of a specific beam group becomes better than a second threshold, the second timer is suspended. The first and second thresholds can be determined by the terminal implementation or can be configured by the network. The first and second timers can use fixed values ​​or can be configured by the network.

[0333] Figure 4H This is a diagram illustrating the operation of a terminal under RLM / RLF according to embodiments of the present disclosure.

[0334] Reference Figure 4HIn operation 4h-05, the terminal derives a first threshold and a second threshold. As an example of the deriving method, the first threshold is the signal quality value of a specific BLER that satisfies the PDCCH of the serving beam. Since the relationship between the first threshold and BLER is affected by terminal performance, it is derived through terminal implementation. The second threshold is the signal quality value of a specific BLER that satisfies the PDCCH of a specific beam. Since the relationship between the second threshold and BLER is affected by terminal performance, it is derived through terminal implementation. Furthermore, the first and second thresholds can be provided from the network. In operation 4h-10, the terminal receives beam group configuration information provided from the network. This configuration information is used to configure the beam group. This information is provided to the terminal via broadcast system information or via dedicated RRC signaling. In operation 4h-15, the terminal configures a group consisting of specific beams serving the TRP. In operation 4h-20, the terminal measures the signal strength of the downlink serving beam and beam group for a specific period. In operation 4h-25, the terminal determines whether the signal quality of the serving beam is better than the first threshold. If the signal quality of the serving beam is better than a first threshold, the terminal maintains data transmission / reception via the serving beam during operation 4h-30. Otherwise, during operation 4h-35, the terminal also determines whether the collective signal quality of the beam group is better than a second threshold. If, for a specific time, the signal quality of the serving beam is lower than the first threshold and the collective signal quality of the specific beam group is higher than the second threshold, the terminal performs operation 4h-40. During operation 4h-40, the terminal performs a first process. The first process is the process of changing the serving beam under the same TRP (Radio Link Recovery). During operation 4h-45, the terminal declares an RLF (Restored Link Failure). During operation 4h-50, the terminal performs a second process. In the second process, the terminal performs a re-establishment process, and after the connection is established, the terminal reports the RLF to the network.

[0335] Figure 4I This is a diagram illustrating the first process according to an embodiment of the present disclosure.

[0336] Reference Figure 4IIn Operation 4i-05, the terminal performs random access processing on the same TRP. The terminal sends a preamble to all beams or a specific beam in the TRP. In response to the preamble, the terminal receives a Random Access Response (RAR) from the specific beam, designating the beam to which the RAR has been sent as the beam with the best signal quality in the TRP or the beam providing the specific signal quality. The RAR includes a UL grant. In Operation 4i-10, the terminal uses the UL grant to send a MAC CE or RRC message indicating that the reason for performing random access is link recovery. Link recovery refers to changing the serving beam to another beam in the same TRP. In Operation 4i-15, the terminal uses the UL grant to send a MAC CE or RRC message, which includes signal quality information for each beam in the TRP, collective signal quality information for the beam group, or signal quality information for each beam in the group.

[0337] The base station that has received the above message will use it to configure the serving beam for the terminal. In operation 4i-20, the terminal receives the serving beam configuration information. In operation 4i-25, the terminal uses the configuration information to configure a new serving beam. Alternatively, the terminal may implicitly designate the specific beam providing the RAR as the new serving beam.

[0338] Figure 4J This is a diagram illustrating the second process according to an embodiment of the present disclosure.

[0339] Reference Figure 4J In Operation 4j-05, during the re-establishment process, the terminal measures all beams or a specific beam offered from the same or adjacent TRPs and searches for the TRP / beam providing the best or specific signal quality. In Operation 4j-10, the terminal performs random access processing. The terminal sends a preamble to all beams or a specific beam in the same or adjacent TRPs. In response to the preamble, the terminal receives a RAR from the specific beam and identifies the beam to which the RAR has been sent as the beam with the best or specific signal quality in the TRP. In Operation 4j-05, the terminal connects to a new serving cell or beam. In Operation 4j-20, the terminal sends a MAC CE or RRC message indicating that the reason for performing random access is the RLA. The Common Control Channel (CCCH) is a type of RRC message.

[0340] Figure 4K This is a diagram illustrating the configuration of a terminal according to an embodiment of the present disclosure.

[0341] Reference Figure 4K The terminal includes an RF processor 4k-10, a baseband processor 4k-20, a storage unit 4k-30, and a controller 4k-40.

[0342] The RF processor 4k-10 performs functions for transmitting and receiving signals via a radio channel (such as signal band conversion and amplification). Specifically, the RF processor 4k-10 performs up-conversion of baseband signals provided by the baseband processor 4k-20 to RF band signals for transmission to the antenna, and down-conversion of RF band signals received by the antenna back to baseband signals. For example, the RF processor 4k-10 may include transmit filters, receive filters, amplifiers, mixers, oscillators, DACs, and ADCs. Although only one antenna is shown in the figures, the terminal may have multiple antennas. Furthermore, the RF processor 4k-10 may include multiple RF chains. Additionally, the RF processor 4k-10 can perform beamforming. For beamforming, the RF processor 4k-10 can adjust the phase and magnitude of signals transmitted or received through multiple antennas or wire elements. Furthermore, the RF processor can perform MIMO and can receive multiple layers during MIMO operation.

[0343] The baseband processor 4k-20 performs the conversion between baseband signals and bit strings according to the system's PHY standard. For example, during data transmission, the baseband processor 4k-20 generates complex symbols by encoding and modulating the transmitted bit string. Furthermore, during data reception, the baseband processor 4k-20 recovers the received bit string by demodulating and decoding the baseband signal provided from the RF processor 4k-10. For example, following the OFDM method, during data transmission, the baseband processor 4k-20 generates complex symbols by encoding and modulating the transmitted bit string, performs mapping of the complex symbols to subcarriers, and then configures the OFDM symbols through IFFT operations and CP insertion. Furthermore, during data reception, the baseband processor 4k-20 divides the baseband signal provided from the RF processor 4k-10 into units of OFDM symbols, recovers the signal mapped to the subcarriers through FFT operations, and then recovers the received bit string through demodulation and decoding.

[0344] The baseband processor 4k-20 and RF processor 4k-10 transmit and receive signals as described above. Therefore, the baseband processor 4k-20 and RF processor 4k-10 can be referred to as a transmitter, receiver, transceiver, or communication unit. Furthermore, to support different radio connectivity technologies, at least one of the baseband processor 4k-20 and RF processor 4k-10 may include multiple communication modules. Additionally, to process signals in different frequency bands, at least one of the baseband processor 4k-20 and RF processor 4k-10 may include different communication modules. For example, different radio connectivity technologies may include LTE networks and NR networks. Furthermore, different frequency bands may include SHF (e.g., 2.5 GHz or 5 GHz) bands and millimeter wave (mmWave) (e.g., 60 GHz, etc.) bands.

[0345] The storage unit 4k-30 can store data including basic programs, applications, and configuration information for the operation of the terminal. Specifically, the storage unit 4k-30 can store information related to a second connection node performing wireless communication using a second radio connection technology. Furthermore, the storage unit 4k-30 provides stored data upon request from the controller 4k-40.

[0346] The controller 4k-40 controls the overall operation of the terminal. For example, the controller 4k-40 transmits and receives signals via a baseband processor 4k-20 and an RF processor 4k-10. Furthermore, the controller 4k-40 records data in or reads data from a storage unit 4k-30. For this purpose, the controller 4k-40 may include at least one processor. For example, the controller 4k-40 may include a CP that performs control for communication and a higher-level AP that controls applications such as applications. The controller 4k-40 may include a multi-connection processor 4k-42.

[0347] Figure 4L This is a diagram illustrating the configuration of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0348] Reference Figure 4L The base station includes an RF processor 4l-10, a baseband processor 4l-20, a backhaul communication unit 4l-30, a storage unit 4l-40, and a controller 4l-50.

[0349] RF processor 4l-10 performs functions for transmitting and receiving signals via a radio channel, such as signal band conversion and amplification. Specifically, RF processor 4l-10 performs up-conversion of baseband signals provided by baseband processor 4l-20 to RF band signals for transmission to the antenna, and down-conversion of RF band signals received by the antenna back to baseband signals. For example, RF processor 4l-10 may include transmit filters, receive filters, amplifiers, mixers, oscillators, DACs, and ADCs. Although only one antenna is shown in the figures, multiple antennas may be configured at the first connection node. Furthermore, RF processor 4l-10 may include multiple RF chains. Additionally, RF processor 4l-10 can perform beamforming. For beamforming, RF processor 4l-10 can adjust the phase and magnitude of signals transmitted or received through multiple antennas or antenna elements. Furthermore, the RF processor can perform downlink MIMO operation by transmitting one or more layers.

[0350] The baseband processor 4l-20 performs the conversion between baseband signals and bit strings according to the PHY standard of the first radio connection technology. For example, during data transmission, the baseband processor 4l-20 generates complex symbols by encoding and modulating the transmitted bit string. Furthermore, during data reception, the baseband processor 4l-20 recovers the received bit string by demodulating and decoding the baseband signal provided from the RF processor 4l-10. For example, following the OFDM method, during data transmission, the baseband processor 4l-20 generates complex symbols by encoding and modulating the transmitted bit string, performs mapping of the complex symbols to subcarriers, and then configures the OFDM symbols through IFFT operations and CP insertion. Furthermore, during data reception, the baseband processor 4l-20 divides the baseband signal provided from the RF processor 4l-20 into units of OFDM symbols, recovers the signal mapped to the subcarriers through FFT operations, and then recovers the received bit string through demodulation and decoding. The baseband processor 4l-20 and the RF processor 4l-10 can transmit and receive signals as described above. Therefore, the baseband processor 4l-20 and the RF processor 4l-10 can be referred to as a transmitter, a receiver, a transceiver, or a communication unit.

[0351] The backhaul communication unit 4l-30 provides an interface for performing communication with other nodes in the network. That is, the backhaul communication unit 4l-30 converts bit strings sent from the primary base station to another node (e.g., an auxiliary base station or CN) into physical signals, and converts physical signals received from said other node into bit strings.

[0352] Storage unit 41-40 stores data including basic programs, application programs, and configuration information for the operation of the main base station. Specifically, storage unit 41-40 can store information about bearers assigned to connected terminals and measurement results reported from connected terminals. Furthermore, storage unit 41-40 can store information that determines whether to provide multiple connections to terminals or suspend multiple connections to terminals. Additionally, storage unit 41-40 can provide stored data upon request from controller 41-50.

[0353] Controller 4l-50 controls the overall operation of the main base station. For example, controller 4l-50 transmits and receives signals via baseband processor 4l-20 and RF processor 4l-10 or via backhaul communication unit 4l-30. Furthermore, controller 4l-50 records data in or reads data from storage unit 4l-40. For this purpose, controller 4l-50 may include at least one processor. Controller 4l-50 may include a multi-connection processor 4l-52.

[0354] <Fifth embodiment>

[0355] In wireless mobile communication systems, it may be necessary to suspend the use of the radio link between the terminal and the network. If data transmission / reception is performed using the suspended radio link, a failure will occur between the terminal and the network. For example, the sequence number used for data transmission / reception may be incorrectly updated, causing subsequent normal operation to fail, or uplink transmission may be performed under extremely adverse conditions, resulting in unnecessary interference.

[0356] To prevent such problems, if a specific event occurs that suspends the use of the radio link, the terminal suspends not only the operation of the physical channel, but also the use of the signaling radio bearer (SRB) and data radio bearer (DRB). In this case, by sensing the type of event that occurred, the terminal suspends the use of all or some of the SRBs.

[0357] As an example, the event could be the start of an RLF or RRC connection suspension process.

[0358] If an RLF is detected, the terminal initiates a cell selection process to search for cells where radio connectivity can be restored, and then initiates an RRC connection re-establishment process in the newly selected cell. The RRC connection re-establishment process involves the terminal sending a specific RRC control message to the base station, and the base station responding to the RRC control message by sending another specific control message to the terminal. In this case, uplink and downlink RRC control messages are sent and received via a bearer called SRB0. SRB0 is a radio bearer for which security is not supported, therefore the integrity of downlink control messages sent via SRB0 cannot be guaranteed.

[0359] The RRC connection suspension process can be initiated when the base station sends a specific control message to the terminal. The RRC connection suspension process is as follows: the terminal and the base station store the currently used configuration information (which may be referred to as context and includes, for example, radio bearer configuration information, security key information, and radio measurement configuration information), and use the stored configuration information to more quickly resume the RRC connection during the next RRC connection. Since the terminal and the base station have already shared the security configuration information, integrity protection is applied to the first downlink control message; for this purpose, SRB1 is used to send the first downlink control message.

[0360] If an event occurs with a suspended radio bearer and the time is an RLF, the terminal suspends the operation of all SRBs except SRB0. If the event is caused by an RRC connection suspension procedure, the terminal suspends the operation of all SRBs except SRB0 and SRB1, so that the following communication suspension procedure can be executed correctly.

[0361] Figure 5AThis is a diagram illustrating the structure of an LTE system that applies some embodiments of the present disclosure according to embodiments of the present disclosure.

[0362] Reference Figure 5A The radio access network for the LTE system includes the ENB, "Node B" or "Base Station" 5a-05, 5a-10, 5a-15 and 5a-20, MME 5a-25 and S-GW 5a-30. The UE or "Terminal" 5a-35 connects to the external network via ENB 5a-05, 5a-10, 5a-15 and 5a-20 and S-GW 5a-30. Figure 5A In this context, ENBs 5a-05, 5a-10, 5a-15, and 5a-20 correspond to existing Node Bs in the Universal Mobile Telecommunications System (UMTS). The ENB connects to the UE 5a-35 via a radio channel and plays a more complex role than the existing Node B. In LTE systems, since all user services, including real-time services via Internet Protocol (IP) such as Voice over Internet Protocol (V2IP), are served through a shared channel, it is necessary to have a device that performs scheduling by merging state information of the UE, such as buffer state, available transmit power state, and channel state. ENBs 5a-05, 5a-10, 5a-15, and 5a-20 are responsible for this process. Typically, one ENB controls multiple cells. To achieve transmission speeds of several hundred Mbps, LTE systems use OFDM as the radio connection technology within a 20 MHz bandwidth. Furthermore, the AMC method for determining the modulation scheme and channel coding rate is applied. The S-GW 5a-30 is a device that provides data bearers and generates or removes data bearers under the control of the MME 5a-25. The MME is a device that is responsible not only for the mobility management of terminals but also for various types of control functions, and it connects to multiple base stations.

[0363] Figure 5B This is a diagram illustrating the radio protocol structure of an LTE system according to an embodiment of the present disclosure.

[0364] Reference Figure 5BIn a terminal or ENB, the radio protocol of an LTE system consists of PDCP 5b-05 or 5b-40, RLC 5b-10 or 5b-35, and MAC 5b-15 or 5b-30. PDCP 5b-05 or 5b-40 is responsible for IP header compression / decompression, encryption / decryption, and integrity security, and performs ARQ operations by reconfiguring the PDCP PDU to the appropriate size. MAC 5b-15 or 5b-30 is connected to the various RLC layer devices configured in a terminal and performs multiplexing of RLC PDU / MAC SDU to MAC PDU and demultiplexing of RLC PDU from MAC PDU. PHY 5b-20 or 5b-25 performs channel coding and modulation of higher-layer data and generates OFDM symbols for transmission over the radio channel, or performs demodulation and channel decoding of OFDM symbols received over the radio channel to transmit the demodulated and decoded OFDM symbols to the upper layer.

[0365] A radio bearer is a logical path formed to provide appropriate QoS and consists of one PDCP device and one or two RLC devices. A radio bearer that processes data generated at a higher layer (e.g., the IP layer) in the user plane is called a DRB. A radio bearer connected to an RRC to process data generated on the RRC is called an SRB. A maximum of three SRBs can be configured in a single terminal.

[0366] SRB0: This is the radio bearer for processing CCCH control messages, and security is not applied to it. Only packets of a specific size are sent to the uplink. The PDCP header and RLC header are not added to RRC control messages sent to / received from SRB0. In other words, RRC control messages are transmitted directly to the MAC without separate processing via PDCP and RLC. Furthermore, the Integrity Message Authentication Code (MAC-I) for integrity protection is not added to downlink RRC control messages sent to / received from SRB0.

[0367] SRB1: This is the radio bearer for processing Dedicated Control Channel (DCCH) control messages. MAC-I is attached to the data transmitted / received via SRB1, and a PDCP layer is added to MAC-I.

[0368] SRB2: This is the radio bearer for handling control messages on the Dedicated Control Channel (DCCH). Control messages with lower priority than those sent / received via SRB1 are transmitted / received through SRB2.

[0369] SRB0 can be used without any separate configuration process, while SRB1 is configured during the RRC connection establishment process, and SRB2 is configured during the RRC connection reconfiguration process.

[0370] Figure 5C This is a diagram illustrating the operation of RLF-related terminals and networks according to embodiments of this disclosure.

[0371] Reference Figure 5C In a mobile communication system consisting of terminal 5c-05 and base station 5c-10, during operation 5c-15, terminal 5c-05 identifies the occurrence of an RLF (Recurrent Leakage Fault). An RLF indicates that a situation has arisen where normal communication between terminal 5c-05 and base station 5c-10 is impossible. For example, it could be that the quality of the downlink channel of the serving cell is currently below a certain reference and has been maintained for more than a predetermined time. During operation 5c-20, terminal 5c-05, having identified the RLF, suspends the remaining SRBs and DRBs except for SRB0.

[0372] Terminal 5c-05 initiates cell selection processing in operation 5c-25 to search for cells that provide downlink channel quality higher than a specific reference, and initiates random access processing in one of the searched cells.

[0373] If uplink transmission resources are allocated through random access processing, then in operation 5c-30, terminal 5c-05 uses the allocated uplink transmission resources to send an RRC Connection Reestablishment Request message via SRB0. This control message includes terminal identifier information, specific code information / security token information generated by the terminal's security key, and connection re-establishment reason information.

[0374] Base station 5c-10 has information related to the RRC connection of terminal 5c-05, which has already sent a control message. If the security token is correct, in operation 5c-35, it accepts the connection re-establishment request and sends an RRC connection re-establishment message to the terminal via SRB0. This control message may include information necessary for security activation, such as information related to the security key. In operation 5c-40, the terminal that has received the control message generates a security key, activates integrity protection and encryption / decryption, and resumes the operation of SRB1. The information related to the security key may be the NextHopChainingCount (NCC) (see 36.331). Then, in operation 5c-45, the terminal performs RRC connection reconfiguration processing by applying the restored SRB1 and activated security, and SRB2 and DRB resume their operations through the processes described above.

[0375] Figure 5D This is a diagram illustrating the operation of a terminal and network involving RRC connection suspension / release according to embodiments of this disclosure.

[0376] Reference Figure 5D In a mobile communication system consisting of terminal 5d-05 and base station 5d-10, during operation 5d-15, base station 5d-10 determines to suspend the RRC connection of terminal 5d-10 and sends an RRC control message including specific control information to terminal 5d-05. For example, if it is desired to resume communication with terminal 5d-05 in a timely manner even though there is no data to be sent to or received from terminal 5d-05, base station 5d-10 may suspend the RRC connection instead of releasing it. For example, the specific information may be the recovery identity to be used when terminal 5d-05 resumes the RRC connection, and paging area information. For example, the paging area information may be a list of cells, and terminal 5d-05 may reselect a cell belonging to the paging area without any separate notification. In the case of reselecting a cell not belonging to the paging area, terminal 5d-05 in the new cell notifies base station 5d-10 that the terminal has moved to the new paging area by sending an RRC control message to base station 5d-10.

[0377] In operation 5d-20, terminal 5d-05, which has received an RRC control message including the specific control information, suspends all SRBs and DRBs except SRB0 and SRB1, and, considering the downlink channel quality of the current serving cell and the downlink channel quality of neighboring cells, performs an operation to determine whether to stay in the current cell or move to a new cell, that is, a cell reselection operation.

[0378] Then, if new uplink data is generated in terminal 5d-05 at a specific time, the terminal initiates random access processing in the current serving cell to restore the RRC connection. During random access processing, terminal 5d-05 is allocated uplink transmission resources from terminal 5d-05, and a specific RRC control message is sent in operation 5d-25. The RRC control message is a control message used to request the restoration of the RRC connection and includes the restoration identity information allocated in operation 5d-15. This control message is sent via SRB0.

[0379] Having received the control message, base station 5d-10 identifies the base station storing the context of terminal 5d-05 by checking the control identity, and subsequently receives the context of terminal 5d-05 from base station 5d-10. Furthermore, base station 5d-10 uses the received context to identify the SRB1 configuration, SRB2 configuration, the security key currently used by terminal 5d-05, and DRB configuration of terminal 5d-05, and sends a control message in operation 5d-30 instructing terminal 5d-05 to restore the RRC connection by applying the existing configuration of terminal 5d-05. This control message is sent via SRB1, and PDCP uses the current security key to generate a MAC-I, which is then sent with the MAC-I appended to the back end of the RRC control message.

[0380] In operation 5d-35, terminal 5d-05, having received the control message, performs integrity verification by checking the MAC-I and uses the information in the control message to restore the RRC connection. Specifically, terminal 5d-05 restores the operation of SRB2 and DRB by calculating a new security key by applying security information (e.g., NCC) included in the control message, and subsequently uses the new key during data transmission / reception. To apply the new security key, terminal 5d-05 re-establishes its RLC and PDCP devices for the restored SRB1 and SRB2 operations. Re-establishing the RLC device represents initializing the RLC sequence number and various types of variables, and re-establishing the PDCP device represents initializing the PDCP sequence number and HFN to 0.

[0381] Figure 5E This is a diagram illustrating the operation of a terminal according to an embodiment of the present disclosure.

[0382] Reference Figure 5E In operation 5e-05, the terminal sensed that an event had occurred that should suspend at least one DRB. Additionally, the terminal sensed that an event had occurred that rendered the current RRC connection unusable.

[0383] In operation 5e-10, the terminal checks the type of event. If the event is caused by an RLF (Recovery Linked Function), the terminal proceeds to operation 5e-15; if the event is caused by the reception of a specific RRC (Recovery Control Message), the terminal proceeds to operation 5e-30. The specific RRC control message may be a control message that includes information on identity recovery and paging area.

[0384] In Operation 5e-15, the terminal suspends all remaining SRBs except SRB0 (SRB1 and SRB2) and performs cell selection processing until the RRC connection restoration condition is triggered. In Operation 5e-20, if the RRC connection restoration condition is triggered—for example, if a cell capable of attempting RRC connection re-establishment is found—the terminal sends a specific RRC control message (RRC Connection Re-establishment Request Message) via SRB0. The RRC control message includes the terminal identifier and terminal security token information.

[0385] In Operation 5e-25, the terminal receives a specific RRC control message (RRC connection re-establishment message) via SRB0. In Operation 5e-27, the terminal generates a new security key by applying the NCC included in the control message and re-establishes the PDCP and RLC of SRB1. Furthermore, the terminal resumes RRC connection operation within the cell.

[0386] In Operation 5e-30, the terminal receives a specific RRC control message and suspends all SRBs except SRB0 and SRB1, specifically SRB2. The terminal disables integrity protection and encryption / decryption so that it can subsequently process downlink control messages without checking integrity via SRB1. The RRC control message includes information such as information about identity restoration. The terminal then performs cell reselection processing until the RRC connection restoration condition is triggered.

[0387] In Operation 5e-35, if an RRC connection restoration condition is triggered—for example, if uplink data is generated or a paging message is received—the terminal sends a specific RRC control message (RRC Connection Restoration Request Message) via SRB0. This control message includes the terminal's restoration identity. The restoration identity in the RRC Connection Restoration Message and the terminal identifier in the RRC Connection Re-establishment Request Message are different from each other. The restoration identity is a combination of the terminal identifier and the identifier of the old base station, while the terminal identifier is the terminal identifier used by the terminal for the old base station and does not include base station-related information.

[0388] In Operation 5e-40, the terminal receives a specific RRC control message and a MAC-I for the RRC control message via SRB1. In Operation 5e-45, the terminal uses the NCC included in the RRC control message to generate a new security key, activate integrity protection, and subsequently verify the MAC-I by applying the new key. If integrity verification is successful, the terminal performs the operations indicated by the RRC control message, such as resuming SRB2 and DRB operations and reactivating encryption / decryption. In this case, the terminal initializes the protocol sequence number, count, and various types of variables by re-establishing the PDCP and RLC of SRB1.

[0389] Figure 5FThis is a diagram illustrating the configuration of a terminal according to an embodiment of the present disclosure.

[0390] Reference Figure 5F The terminal includes an RF processor 5f-10, a baseband processor 5f-20, a storage unit 5f-30, and a controller 5f-40.

[0391] RF processor 5f-10 performs functions for transmitting and receiving signals via a radio channel, such as signal band conversion and amplification. Specifically, RF processor 5f-10 performs up-conversion of baseband signals provided by baseband processor 5f-20 to RF band signals for transmission to the antenna, and down-conversion of RF band signals received by the antenna back to baseband signals. For example, RF processor 5f-10 may include transmit filters, receive filters, amplifiers, mixers, oscillators, DACs, and ADCs. Although only one antenna is shown in the figures, the terminal may be equipped with multiple antennas. Furthermore, RF processor 1j-10 may include multiple RF chains.

[0392] The baseband processor 5f-20 performs the conversion between baseband signals and bit strings according to the system's PHY standard. For example, during data transmission, the baseband processor 5f-20 generates complex symbols by encoding and modulating the transmitted bit string. Furthermore, during data reception, the baseband processor 5f-20 recovers the received bit string by demodulating and decoding the baseband signal provided from the RF processor 5f-10. For example, following the OFDM method, during data transmission, the baseband processor 5f-20 generates complex symbols by encoding and modulating the transmitted bit string, performs mapping of the complex symbols to subcarriers, and then configures the OFDM symbols through IFFT operations and CP insertion. Furthermore, during data reception, the baseband processor 5f-20 divides the baseband signal provided from the RF processor 5f-10 into units of OFDM symbols, recovers the signal mapped to the subcarriers through FFT operations, and then recovers the received bit string through demodulation and decoding.

[0393] The baseband processor 5f-20 and RF processor 5f-10 can transmit and receive signals as described above. Therefore, the baseband processor 5f-20 and RF processor 5f-10 can be referred to as transmitters, receivers, transceivers, or communication units. Furthermore, to support different radio connection technologies, at least one of the baseband processor 5f-20 and RF processor 5f-10 may include multiple communication modules. Additionally, to process signals in different frequency bands, at least one of the baseband processor 5f-20 and RF processor 5f-10 may include different communication modules.

[0394] Storage unit 5f-30 stores data containing basic programs, application programs, and configuration information for the operation of the terminal. Storage unit 5f-30 provides the stored data according to requests from controller 5f-40.

[0395] Controller 5f-40 controls the overall operation of the terminal. For example, controller 5f-40 transmits and receives signals via baseband processor 5f-20 and RF processor 5f-10. Furthermore, controller 5f-40 records data in or reads data from storage unit 5f-30. Additionally, controller 5f-40 controls the suspension and resumption of operation of SRB and DRB. For this purpose, controller 5f-40 may include at least one processor. For example, controller 5f-40 may include a CP that performs control for communication and a higher-level AP that controls applications such as applications. Controller 5f-40 may include a multi-connection processor 5f-42.

[0396] Figure 5G This is a diagram illustrating the configuration of a base station in a wireless communication system according to an embodiment of the present disclosure.

[0397] Reference Figure 5G The base station includes an RF processor 5g-10, a baseband processor 5g-20, a backhaul communication unit 5g-30, a storage unit 5g-40, and a controller 5g-50.

[0398] RF processor 5g-10 performs functions for transmitting and receiving signals via a radio channel, such as signal band conversion and amplification. Specifically, RF processor 5g-10 performs up-conversion of baseband signals provided by baseband processor 5g-20 to RF band signals for transmission to the antenna, and down-conversion of RF band signals received by the antenna back to baseband signals. For example, RF processor 5g-10 may include transmit filters, receive filters, amplifiers, mixers, oscillators, DACs, and ADCs. Although only one antenna is shown in the figures, multiple antennas may be configured at the first connection node. Furthermore, RF processor 5g-10 may include multiple RF chains.

[0399] The baseband processor 5g-20 performs the conversion between baseband signals and bit strings according to the PHY standard of the first radio connection technology. For example, during data transmission, the baseband processor 5g-20 generates complex symbols by encoding and modulating the transmitted bit string. Furthermore, during data reception, the baseband processor 5g-20 recovers the received bit string by demodulating and decoding the baseband signal provided from the RF processor 5g-10. For example, following the OFDM method, during data transmission, the baseband processor 5g-20 generates complex symbols by encoding and modulating the transmitted bit string, performs mapping of the complex symbols to subcarriers, and then configures the OFDM symbols through IFFT operations and CP insertion. Furthermore, during data reception, the baseband processor 5g-20 divides the baseband signal provided from the RF processor 5g-10 into units of OFDM symbols, recovers the signal mapped to the subcarriers through FFT operations, and then recovers the received bit string through demodulation and decoding. The baseband processor 5G-20 and the RF processor 5G-10 can transmit and receive signals as described above. Therefore, the baseband processor 5G-20 and the RF processor 5G-10 can be referred to as a transmitter, a receiver, a transceiver, or a communication unit.

[0400] The 5G-30 backhaul communication unit provides an interface for performing communication with other nodes in the network.

[0401] Storage unit 5g-40 stores data containing basic procedures, application programs, and configuration information for the operation of the main base station. Specifically, storage unit 5g-40 can store information about bearers assigned to connected terminals and measurement results reported from connected terminals. Furthermore, storage unit 5g-40 can store information that determines whether to provide multiple connections to terminals or suspend multiple connections to terminals. Additionally, storage unit 5g-40 provides stored data according to requests from controller 5g-50.

[0402] The controller 5g-50 controls the overall operation of the main base station. For example, the controller 5g-50 transmits and receives signals via the baseband processor 5g-20 and the RF processor 5g-10, or via the backhaul communication unit 5g-30. Furthermore, the controller 5g-50 records data in or reads data from the storage unit 5g-40. For this purpose, the controller 5g-50 may include at least one processor. For example, the controller 5g-50 may include a multi-connectivity processor 5g-52.

[0403] <Sixth embodiment>

[0404] In wireless mobile communication systems, it may be necessary to suspend the use of the radio link between the terminal and the network. If data transmission / reception is performed using the suspended radio link, a failure may occur between the terminal and the network. For example, the sequence number used for data transmission / reception may be incorrectly updated, causing subsequent malfunctions, or uplink transmissions may be performed under extremely adverse conditions, resulting in unnecessary interference.

[0405] To prevent such problems, if a specific event occurs that suspends the use of the radio link, the terminal suspends not only the operation of the physical channel but also the use of the SRB.

[0406] The RRC connection suspension process can begin when the base station sends a specific control message to the terminal. The RRC connection suspension process is as follows: the terminal and the base station store the currently used configuration information (which may be referred to as the UE context and includes, for example, radio bearer configuration information, security key information, and radio measurement configuration information; hereinafter referred to as the "terminal context"), and during the next RRC connection, the stored configuration information is used to restore the RRC connection more quickly. Since the terminal and the base station have already shared the security configuration information, integrity protection is applied to the first downlink control message; for this purpose, SRB1 is used to send the first downlink control message.

[0407] However, if the base station to which the terminal intends to reconnect is not the base station previously connected to the terminal, but a new base station due to the terminal's mobility, a problem arises in receiving the first downlink control message. This is because if the new base station has a security configuration different from that of the terminal, the terminal cannot decode the encrypted control message that the terminal has already received from SRB1. This problem occurs because the next-hop chain count (hereinafter referred to as "NCC") value assigned to the terminal by the base station will be substantially different from one base station to another.

[0408] Embodiments of this disclosure propose operations for base stations and terminals such that, even if the terminal connects to a new base station, the base station and the terminal can normally send / receive control messages to / from each other when the base station and the terminal restore their connection after suspending it.

[0409] Embodiment 6-1 of this disclosure proposes a method in which the NCC to be used during the next connection restoration is pre-allocated to the RRC connection release message sent by the base station to suspend the connection to the terminal, and when the connection is restored, the terminal re-establishes the PDCP of SRB1 by using the NCC to generate a new security key, so that the terminal and the base station can send and receive control messages normally.

[0410] For specific reasons, a base station may release a connection to a terminal. When releasing a connection to a terminal, the base station sends an RRC connection release message (first RRC message) to the terminal. The first RRC message may include a recovery identity, next-hop chain count (NCC), and paging area information that the terminal will use when resuming the RRC connection. If the message is received, the terminal may switch to an RRC idle state or an RRC disabled state after storing the terminal context and NCC that will be used when subsequently resuming the connection. The terminal context, also known as the UE context, includes, for example, radio bearer configuration information, security key information, and radio measurement configuration information. The terminal may move between cells within the paging area without reporting such movement to the base station, and if the terminal leaves the paging area, it may report the current cell and update the paging area. The paging area may indicate a list of cells or a paging identifier (ID). If the base station and the terminal intend to resume their connection for specific reasons, the terminal includes its recovery identity (recovery ID) in an RRC connection resumption request message (second RRC message) to send it to the current cell. Before sending the RRC connection restoration request message, the terminal performs synchronization with the current cell to learn the target physical cell identity (PCI) and target frequency. Before sending the RRC connection restoration request message, the terminal generates a new key using the target PCI and target frequency of the current cell, receives the NCC received from the first RRC message for storage, and uses this key to re-establish the PDCP of SRB1. Furthermore, the terminal sends the RRC connection restoration request message, receives the corresponding RRC connection restoration message (third message), and uses the established PDCP of SRB1 to decode and confirm the RRC connection restoration message.

[0411] The sixth-first embodiment of this disclosure includes the following operations.

[0412] —The terminal receives the first RRC message, which includes the recovery identity (recovery ID) and the next-hop chain count (NCC).

[0413] —After receiving the first RRC message, the terminal begins operations based on the UE's mobility.

[0414] —An operation that occurs when one of the predefined events happens.

[0415] —The NCC received and the terminal generates a new security key based on the current cell's cell identity.

[0416] —The terminal re-establishes the PDCP of SRB1.

[0417] —The terminal sends a second RRC message, including the recovery identity (ID), to the current cell.

[0418] —The operation of the terminal receiving the third RRC message from the current cell via SRB1.

[0419] —The terminal uses the newly generated security key to decode and confirm the received third RRC message.

[0420] —The terminal restores the DRB based on the third RRC message and sends data through the DRB.

[0421] The second RRC message is sent to SRB0, and the predefined events may include the following.

[0422] —The situation where the terminal receives a paging message from the current cell.

[0423] —The situation where the terminal receives downlink scheduling information from the current cell.

[0424] —A situation arises where uplink data will be sent by the terminal.

[0425] Embodiment 6-2 of this disclosure proposes a method in which, if a connection is restored after a connection to a terminal is suspended by a base station, the base station includes an NCC in an unencrypted PDCP control PDU of an RRC connection restoration message to be sent, and the terminal receives the NCC, generates a new security key based on it, and establishes a PDCP for SRB1, enabling the terminal and the base station to send and receive control messages normally.

[0426] For specific reasons, a base station may release a connection to a terminal. When releasing a connection to a terminal, the base station sends an RRC connection release message (first RRC message) to the terminal. The first RRC message may include a recovery identity to be used by the terminal when resuming the RRC connection, and paging area information. If the message is received, the terminal may switch to an RRC idle state or an RRC disabled state after storing the terminal context and NCC to be used when subsequently resuming the connection. The terminal context is also referred to as the UE context and may include, for example, radio bearer configuration information, security key information, and radio measurement configuration information. The terminal may move between cells within the paging area without reporting such movement to the base station, and if the terminal leaves the paging area, it may report the current cell and update the paging area. The paging area may indicate a list of cells or a paging ID. If the base station and the terminal intend to resume their connection for specific reasons, the terminal includes a recovery identity (recovery ID) in an RRC connection resumption request message (second RRC message) to send it to the current cell. Before sending the RRC connection resumption request message, the terminal performs synchronization with the current cell to know the target PCI and target frequency. The base station receives the RRC connection restoration request message, analyzes the restoration ID, and sends a terminal context request message (first message) to the terminal's old base station. In this case, the old base station generates a new security key based on the NCC, the new base station's target PCI, and the target frequency, and transmits both the security key and the NCC to the new base station. In response to the terminal's RRC connection restoration request message, the new base station sends an RRC connection restoration message (third RRC message) and an unencrypted PDCP control PDU including the NCC to the terminal. The terminal receives the RRC connection restoration message, confirms the NCC in the unencrypted PDCP control PDU, generates a new security key along with the target PCI and target frequency, establishes PDCP for SRB1, confirms the RRC connection restoration message, and executes the connection restoration process.

[0427] Embodiment 6-2 of this disclosure includes the following operations.

[0428] —The terminal receives a first RRC message including the recovery identity (recovery ID).

[0429] —After receiving the first RRC message, the terminal begins operations based on the UE's mobility.

[0430] —An operation that occurs when one of the predefined events happens.

[0431] —The terminal sends a second RRC message, including the recovery identity (recovery ID), to the current cell.

[0432] —The operation of a new base station requesting terminal context from the terminal's old base station.

[0433] —The operation of using the NCC and information (PCI and frequency) of the new base station (the current cell of the terminal) to generate a new security key.

[0434] —The process of the old base station transmitting the new security key and NCC to the new base station.

[0435] —The new base station will include the NCC in the operation of the resulting unencrypted PDCP control PDU.

[0436] —The new base station sends the third RRC message and the PDCP control PDU, including the NCC, to SRB1.

[0437] —The terminal requests the operation of the third RRC cell from the current cell via SRB1.

[0438] —The terminal confirms the NCC operation based on the unencrypted PDCP control PDU.

[0439] —The operation of the NCC and the terminal to generate a new security key based on the current cell identity.

[0440] —The terminal re-establishes the PDCP operation of SRB1 based on the new security key.

[0441] —The terminal uses the newly generated security key to decode and confirm the received third RRC message.

[0442] —The terminal restores the DRB based on the third RRC message and sends data through the DRB.

[0443] The second RRC message is sent to SRB0, and the predefined events may include the following.

[0444] —The situation where the terminal receives a paging message from the current cell.

[0445] —The situation where the terminal receives downlink scheduling information from the current cell.

[0446] —A situation arises where uplink data will be sent by the terminal.

[0447] Figure 6A This is a diagram illustrating the structure of an LTE system that applies some embodiments of the present disclosure according to embodiments of the present disclosure.

[0448] Reference Figure 6AThe radio access network for the LTE system includes the ENB, "Node B" or "Base Station" 6a-05, 6a-10, 6a-15 and 6a-20, MME 6a-25 and S-GW 6a-30. The UE or "Terminal" 6a-35 connects to the external network via ENB 6a-05, 6a-10, 6a-15 and 6a-20 and S-GW 6a-30. Figure 6A In LTE, ENBs 6a-05, 6a-10, 6a-15, and 6a-20 correspond to the existing Node Bs in UMTS. The ENB connects to the UE 6a-35 via a radio channel and plays a more complex role than the existing Node B. In LTE systems, since all user services, including real-time services via Internet Protocol (IP) and VoIP, are served through a shared channel, it is necessary to have a device that performs scheduling by consolidating UE state information such as buffer state, available transmit power state, and channel state. ENBs 6a-05, 6a-10, 6a-15, and 6a-20 are responsible for this process. Typically, one ENB controls multiple cells. To achieve transmission speeds of several hundred Mbps, LTE systems use OFDM as the radio connection technology in a 20 MHz bandwidth. Furthermore, the AMC method for determining the modulation scheme and channel coding rate is applied. The S-GW 6a-30 is a device that provides data bearers and generates or removes data bearers under the control of the MME 6a-25. The MME is a device that is responsible not only for the mobility management of terminals but also for various types of control functions, and it connects to multiple base stations.

[0449] Figure 6B This is a diagram illustrating the radio protocol structure of an LTE system according to an embodiment of the present disclosure.

[0450] Reference Figure 6BIn a terminal or ENB, the radio protocol of an LTE system consists of PDCP 6b-05 or 6b-40, RLC 6b-10 or 6b-35, and MAC 6b-15 or 6b-30. PDCP 6b-05 or 6b-40 is responsible for IP header compression / decompression, encryption / decryption, and integrity security, and performs ARQ operations by reconfiguring PDCP PDUs to appropriate sizes. MAC 6b-15 or 6b-30 is connected to the various RLC layer devices configured in a terminal and performs multiplexing of RLC PDU / MAC SDU to MAC PDU and demultiplexing of RLC PDU from MAC PDU. PHY 6b-20 or 6b-25 performs channel coding and modulation of upper-layer data and generates OFDM symbols for transmission over the radio channel, or performs demodulation and channel decoding of OFDM symbols received over the radio channel to transmit the demodulated and decoded OFDM symbols to a higher layer.

[0451] A radio bearer is a logical path formed to provide appropriate QoS and consists of one PDCP device and one or two RLC devices. A radio bearer that processes data generated at a higher layer (e.g., the IP layer) in the user plane is called a DRB. A radio bearer connected to an RRC to process data generated on the RRC is called an SRB. A maximum of three SRBs can be configured in a single terminal.

[0452] SRB0: This is the radio carrier that processes CCCH control messages and does not apply security to it. Only packets of a specific size are sent to the uplink. The PDCP header and RLC header are not added to RRC control messages sent to / received from SRB0. In other words, RRC control messages are transmitted directly to the MAC without being processed separately via PDCP and RLC. Furthermore, MAC-I for integrity protection is not added to downlink RRC control messages sent to / received from SRB0.

[0453] SRB1: This is the radio carrier for processing Dedicated Control Channel (DCCH) control messages. MAC-I is attached to the data transmitted / received via SRB1, and a PDCP layer is added to MAC-I.

[0454] SRB2: This is the radio bearer for processing DCCH control messages. Control messages with lower priority than those sent / received via SRB1 are transmitted / received through SRB2.

[0455] SRB0 can be used without any separate configuration process, while SRB1 is configured during the RRC connection establishment process, and SRB2 is configured during the RRC connection reconfiguration process.

[0456] Figure 6C and Figure 6D This is a diagram illustrating the sixth-first embodiment of the present disclosure.

[0457] Figure 6C This is a diagram illustrating the process of releasing a connection from a network to a terminal according to embodiment 6-1 of this disclosure.

[0458] Reference Figure 6C In a mobile communication system consisting of terminal 6c-01, base station 6c-02, MME 6c-03, and S-GW 6c-04, while terminal 6c-01 and the network are sending / receiving data to each other in operations 6c-05 and 6c-10, base station 6c-02 can determine to suspend the RRC connection of terminal 6c-01 in operation 6c-15, and can release or suspend SRB and DRB in operation 6c-20. Furthermore, in operation 6c-25, base station 6c-02 sends an RRC control message (RRC connection release message) including specific control information to terminal 6c-01. For example, if it is desired to promptly resume communication with terminal 6c-01 even though there is no data to be sent to or received from terminal 6c-01, base station 6c-02 can suspend the RRC connection instead of releasing the RRC connection of terminal 6c-01. As an example, specific information in the RRC connection release message could be the recovery identity, next-hop chain count (NCC), and paging area information that terminal 6c-01 will use when resuming the RRC connection. For example, the paging area information could be a list of cells, and terminal 6c-01 could reselect a cell belonging to the paging area without notifying base station 6c-02 of any separate notification. In the case of reselecting a cell not belonging to the paging area, terminal 6c-01 in the new cell can notify base station 6c-02 that the terminal has moved to the new paging area by sending an RRC control message, and the paging area can be updated. In operation 6c-30, terminal 6c-01, having received the RRC control message (RRC connection release message) including the specific control information, suspends all SRBs and DRBs and stores the terminal context and NCC. For example, the terminal context (also called the UE context) could include radio bearer configuration information, security key information, and radio measurement configuration information, and the NCC would be necessary for security configuration when further resuming the connection.

[0459] Then, the terminal considers the downlink channel quality of the current serving cell and the downlink channel quality of neighboring cells to perform an operation to determine whether to continue staying in the current cell or move to a new cell, i.e., cell reselection operation.

[0460] Figure 6D This is a diagram illustrating the process of restoring connection between a terminal and a network according to embodiment 6-1 of this disclosure.

[0461] Reference Figure 6D In operation 6d-10, if a specific reason for resuming the connection occurs at a specific time, for example, if new uplink data appears in terminal 6d-01, then in operations 6d-15 and 6d-20, terminal 6d-01 initiates random access processing in the current serving cell to resume the RRC connection. During random access processing, terminal 6d-01 is allocated uplink transmission resources from the base station for sending specific RRC control messages. Before sending the RRC control messages, the terminal uses the target PCI, target frequency, and... Figure 6C Operation 6c-25 receives the NCC data to generate a new security key. The security key may include KeNB*. Furthermore, in operation 6d-25, terminal 6d-01 re-establishes the PDCP of SRB1 to apply the newly generated security key.

[0462] If operation 6d-25 is completed, then in operation 6d-30, terminal 6d-01 will send an RRC control message to the new base station 6d-02. The RRC control message is a control message used to request the restoration of the RRC connection and may include information about... Figure 6C The operation 6c-25 assigns the recovery identity (hereinafter referred to as the recovery ID), recovery reason, and short recovery MAC-I information. This control message is sent via uplink SRB0.

[0463] In operations 6d-35, 6d-40, and 6d-45, the new base station 6d-02, having already received control messages, identifies the old base station 6d-03 storing the terminal context by checking the recovery ID, and then receives the terminal context from the old base station 6d-03. In this case, the old base station 6d-03 uses... Figure 6C The NCC information transmitted when releasing the connection to terminal 6d-01, along with the PCI and frequency information of the new base station, is used to generate a new security key, which is then transmitted to the new base station. The security key may include KeNB*. Furthermore, in operation 6d-50, the new base station 6d-02 sends a control message instructing the terminal to restore the RRC connection, so that the RRC connection can be restored using the received terminal context and the new security key by applying the terminal's SRB1 configuration, SRB2 configuration, and DRB configuration.

[0464] The control message is sent via SRB1, and PDCP uses the new security key to generate a MAC-I, which is then sent with the MAC-I appended to the back end of the RRC control message. This control message may include NCC. In operation 6d-55, terminal 6d-01, having received the control message, checks the MAC-I based on the new security key generated in operation 6d-25 and the established PDCP for SRB1 to perform integrity verification, and uses the information in the control message to restore the RRC connection. More specifically, terminal 6d-01 restores the operation of SRB2 and DRB, and re-establishes the RLC and PDCP devices of SRB2 and DRB to apply the newly generated security key. The re-establishment of the RLC device represents the initialization of the RLC sequence number and various types of variables, and the re-establishment of the PDCP device represents the initialization of the PDCP sequence number and HFN to 0.

[0465] After the process described above is completed, in operation 6d-60, terminal 6d-01 sends a control message indicating that the restoration of the RRC connection is complete to the new base station 6d-02. If the new base station 6d-02 receives the RRC connection restoration completion message, it restores the DRB. In operation 6d-65, if the DRB is released, the new base station 6d-02 performs the process of regenerating the DRB; if the DRB is suspended, the base station performs the process of correcting and restoring the DRB path. Then, in operation 6d-70, the new base station 6d-02 requests the old base station 6d-03 to release the terminal context. Then, in operations 6d-75 and 6d-80, terminal 6d-01 sends data to / receives data from the network while in RRC connected state.

[0466] Figure 6E This is a diagram illustrating the operation of a terminal according to embodiment 6-1 of this disclosure.

[0467] Reference Figure 6EIf, in operation 6e-05, the base station determines that the terminal's RRC connection is suspended while the terminal and network are sending / receiving data to each other, and sends an RRC control message (RRC connection release message) including specific control information to the terminal, then in operation 6e-10, the terminal receives the RRC control message. The specific information in the RRC connection release message may be the recovery identity, next-hop chain count (NCC), and paging area information that will be used when the terminal resumes the RRC connection. Having received the RRC control message (RRC connection release message) including control information, the terminal suspends all SRBs and DRBs and stores the terminal context and NCC. As an example, the terminal context (also called the UE context) may include radio bearer configuration information, security key information, and radio measurement configuration information, and the NCC will be necessary for security configuration when the connection is further resumed. The terminal then considers the downlink channel quality of the current serving cell and the downlink channel quality of neighboring cells to perform an operation to determine whether to remain in the current cell or move to a new cell, i.e., a cell reselection operation. In Operation 6e-15, if a specific reason for resuming the connection occurs at a specific time, for example, if new uplink data appears in terminal 6d-01, then in Operation 6e-20, the terminal initiates random access processing in the current serving cell to resume the RRC connection. During random access processing, the terminal is allocated uplink transmission resources from the base station for sending specific RRC control messages. Before sending the RRC control messages, the terminal uses the target PCI, target frequency, and... Figure 6C Operation 6c-25 receives the NCC to generate a new security key. The security key may include KeNB*. Furthermore, in operation 6e-20, the terminal re-establishes the PDCP and RLC of SRB1 to apply the newly generated security key.

[0468] If operation 6e-20 is completed, in operation 6e-25, the terminal sends an RRC control message to the base station. The RRC control message is a control message used to request the restoration of the RRC connection and may include information about the restoration identity (hereinafter referred to as the restoration ID) assigned in operation 6e-10, the restoration reason, and the short restoration MAC-I. In operation 6e-30, the base station sends a control message instructing the terminal to restore the RRC connection, and the terminal receives the control message. This control message is sent via SRB1, and in the base station, PDCP uses the current new security key to generate the MAC-I and sends it with the MAC-I appended to the back of the RRC control message. This control message may include NCC. In operation 6e-30, the terminal that has received the control message checks the MAC-I to perform integrity verification based on the new security key generated in operation 6e-20 and the established SRB1 via PDCP, and uses the information in the control message to restore the RRC connection. More specifically, the terminal resumes the operation of SRB2 and DRB, and re-establishes the RLC and PDCP devices for SRB2 and DRB to apply the newly generated security keys. The re-establishment of the RLC device represents the initialization of the RLC sequence number and various types of variables, while the re-establishment of the PDCP device represents the initialization of the PDCP sequence number and HFN to 0. After the process described above is completed, in operation 6e-35, the terminal sends a control message indicating that the restoration of the RRC connection is complete to the base station.

[0469] Figure 6F and Figure 6G This is a diagram illustrating the sixth-second embodiment according to the present disclosure.

[0470] Figure 6F The process of releasing a network connection to a terminal according to the sixth-second embodiment of this disclosure is illustrated.

[0471] Reference Figure 6FIn a mobile communication system consisting of terminal 6f-01, base station 6f-02, MME 6f-03, and S-GW 6f-04, while terminal 6f-01 and the network are sending / receiving data to each other in operations 6f-05 and 6f-10, base station 6f-02 can determine to suspend the RRC connection of terminal 6f-01 in operation 6f-15, and can release or suspend SRB and DRB in operation 6f-20. Furthermore, in operation 6f-25, base station 6f-02 sends an RRC control message (RRC connection release message) including specific control information to terminal 6f-01. For example, if it is desired to promptly resume communication with terminal 6f-01 even though there is no data to be sent to or received from terminal 6f-01, base station 6f-02 can suspend the RRC connection instead of releasing the RRC connection of terminal 6f-01. As an example, specific information in the RRC connection release message could be the recovery identity, next-hop chain count (NCC), and paging area information that terminal 6f-01 will use when it resumes the RRC connection. For example, the paging area information could be a list of cells, and terminal 6f-01 could reselect a cell belonging to the paging area without notifying base station 6f-02 of any separate notification. In the case of reselecting a cell not belonging to the paging area, terminal 6f-01 in the new cell can notify base station 6f-02 that terminal 6f-01 has moved to the new paging area by sending an RRC control message, and can update the paging cell. In operation 6f-30, terminal 6f-01, having received the RRC control message (RRC connection release message) including the specific control information, suspends all SRBs and DRBs and stores the terminal context. As an example, the terminal context (also called the UE context) could include radio bearer configuration information, security key information, and radio measurement configuration information. Terminal 6f-01 considers the downlink channel quality of the current serving cell and the downlink channel quality of neighboring cells to perform an operation to determine whether to continue staying in the current cell or move to a new cell, i.e., cell reselection operation.

[0472] Figure 6G This is a diagram illustrating the process of restoring connection between a terminal and a network according to embodiment 6-2 of this disclosure.

[0473] Reference Figure 6GIn operation 6g-10, if a specific reason for resuming the connection occurs at a specific time, for example, if new uplink data appears in terminal 6g-01, then in operations 6g-15 and 6g-20, terminal 6g-01 initiates random access processing in the current serving cell to resume the RRC connection. During the random access processing, terminal 6g-01 is allocated uplink transmission resources from the new base station 6g-02 for sending specific RRC control messages, and in operation 6g-25, the RRC control message is sent to the new base station 6g-02. The RRC control message is a control message used to request the resumption of the RRC connection and may include information about... Figure 6FOperation 6f-25 assigns the recovery identity (hereinafter referred to as the recovery ID), recovery reason, and short recovery MAC-I information. This control message is sent via uplink SRB0. In operations 6g-30 and 6g-40, the new base station 6d-02, having received the control message, identifies the old base station 6g-03 storing the terminal context by checking the recovery ID, and then receives the terminal context from that base station. In this case, the old base station 6g-03 can use the new NCC for the new security configuration of the new base station 6g-02, as well as the PCI and frequency information of the current new base station 6g-02 for terminal 6g-01, to generate a new security key, and can transmit the new security key along with the NCC to the new base station 6g-02. The security key may include KeNB*. Operation 6g-35 can be replaced by the following process: the old base station 6g-03 sends the old security configuration key KeNB* to the new base station 6g-02, and the new base station 6g-02 uses the NCC, PCI, and frequency information generated by the new base station to generate a new security key KeNB*. Furthermore, in operation 6g-45, the new base station can generate an unencrypted PDCP control PDU to transmit NCC information to terminal 6g-01, which is unaware of the new security configuration. The PDCP control PDU may include NCC information. In operation 6g-50, the new base station 6g-02 sends a control message to terminal 6g-01 instructing terminal 6g-01 to restore the RRC connection, so as to apply the terminal SRB1 configuration, SRB2 configuration, and DRB configuration by using the terminal context and the new security key, as well as the unencrypted PDCP control PDU, to restore the RRC connection. The control message is sent via SRB1, and PDCP uses the current security key to generate a MAC-I, which is sent with the MAC-I appended to the back end of the RRC control message. This control message may include NCC. Since terminal 6g-01, having already received the control message, cannot decode it, in operation 6g-55, it first receives the NCC from the unencrypted PDCP control PDU to transmit the NCC to the RRC layer. The RRC layer then uses the NCC, the target PCI of the current cell, and the target frequency to generate a new security key. The security key may include KeNB*. Furthermore, in operation 6g-60, to apply the new security key, the PDCP and RLC of SRB1 are re-established. Terminal 6g-01 checks the MAC-I based on the newly generated security key and the re-established PDCP of SRB1 to perform integrity verification, and restores the RRC connection by confirming the information included in the control message. More specifically, terminal 6g-01 resumes the operation of SRB2 and DRB, and re-establishes the RLC and PDCP devices of SRB2 and DRB to apply the newly generated security key. The re-establishment of the RLC device represents the initialization of the RLC sequence number and various types of variables, and the re-establishment of the PDCP device represents the initialization of the PDCP sequence number and HFN to 0.After the process described above is completed, in operation 6g-65, terminal 6g-01 sends a control message indicating that the restoration of the RRC connection is complete to the new base station 6g-02. If the new base station 6g-02 receives the RRC connection restoration completion message, it restores the DRB. In operation 6g-70, if the DRB is released, the new base station 6g-02 performs the process of regenerating the DRB; if the DRB is suspended, the new base station 6g-02 performs the process of correcting and restoring the DRB path. Then, in operation 6g-75, the new base station 6d-02 requests the old base station 6d-03 to release the terminal context. Subsequently, in operations 6g-80 and 6g-85, terminal 6d-01 sends data to / receives data from the network while in RRC connected state.

[0474] The PDCP control PDU can have the following structure.

[0475] D / C DPU type R NCC

[0476] Table 1 PDCP control PDU format 1

[0477] D / C DPU type NCC R

[0478] Table 2 PDCP control PDU format 1

[0479] PDCP control PDUs are unencrypted PDUs and may include NCC as described above. A PDCP control PDU may be one byte in size, comprising 3 bits of NCC, 3 bits of PDU type, 1 bit of D / C, and 1 reserved bit. If the 1-bit D / C is "0", it indicates a control PDU; if the D / C is "1", it indicates a data PDU. The 3-bit PDU type can be redefined according to 011-111 for NCC transmissions.

[0480] If the base station determines to suspend the terminal's RRC connection while the terminal and network are sending / receiving data to each other, and sends an RRC control message (RRC connection release message) including specific control information to the terminal, the terminal receives the RRC control message. The specific information in the RRC connection release message may be the recovery identity and paging area information that the terminal will use when resuming the RRC connection. Having received the RRC control message (RRC connection release message) including control information, the terminal suspends all SRBs and DRBs and stores the terminal context. As an example, the terminal context (also called the UE context) may include radio bearer configuration information, security key information, and radio measurement configuration information.

[0481] Then, the terminal considers the downlink channel quality of the current serving cell and the downlink channel quality of neighboring cells to perform an operation to determine whether to remain in the current cell or move to a new cell, i.e., a cell reselection operation. If a specific reason for resuming the connection occurs at a specific time, for example, if new uplink data appears in the terminal, the terminal initiates random access processing in the current serving cell to restore the RRC connection. In the random access processing, the terminal is allocated uplink transmission resources from the base station for sending a specific RRC control message and sends the RRC control message to the base station. The RRC control message is a control message used to request the restoration of the RRC connection and may include information about the allocated restoration identity (hereinafter referred to as the restoration ID), the restoration reason, and the short restoration MAC-I. This control message is sent via uplink SRB0. The base station that has received the control message identifies the old base station storing the terminal context by checking the restoration ID, and receives the terminal context from that base station through operations 6g-30, 6g-35, and 6g-40, and receives the new security key and NCC. The new base station can generate an unencrypted PDCP control PDU to transmit NCC information to terminals unaware of the new security configuration. The PDCP control PDU may include NCC information. The base station sends a control message instructing the terminal to restore the RRC connection by applying the SRB1, SRB2, and DRB configurations using the terminal context and the new security key. The base station also sends an unencrypted PDCP control PDU including the NCC. This control message is sent via SRB1, and PDCP generates a MAC-I using the new security key, sending the MAC-I with it appended to the back of the RRC control message. This control message may include the NCC.

[0482] Since the terminal that has received the control message cannot decode it, it first uses the unencrypted PDCP control PDU to receive the NCC to transmit the NCC to the RRC layer. The RRC layer then uses the NCC, the target PCI of the current cell, and the target frequency to generate a new security key. The security key may include KeNB*. Furthermore, to apply the new security key, the PDCP and RLC of SRB1 are re-established. The terminal performs integrity verification by checking the MAC-I based on the generated new security key and the re-established PDCP of SRB1, and uses the information in the control message to restore the RRC connection. More specifically, the terminal restores the operation of SRB2 and DRB, and re-establishes the RLC and PDCP devices of SRB2 and DRB to apply the newly generated security key. The re-establishment of the RLC device indicates the initialization of the RLC sequence number and various types of variables, and the re-establishment of the PDCP device indicates the initialization of the PDCP sequence number and HFN to 0. After the above-described process is completed, the terminal sends a control message indicating that the restoration of the RRC connection is complete to the base station.

[0483] The terminal includes an RF processor, a baseband processor, a storage unit, and a controller.

[0484] The RF processor performs functions for transmitting and receiving signals over a radio channel, such as signal band conversion and amplification. That is, the RF processor performs up-conversion of baseband signals provided by the baseband processor to RF band signals for transmission to the antenna, and down-conversion of RF band signals received by the antenna back to baseband signals. For example, the RF processor may include transmit filters, receive filters, amplifiers, mixers, oscillators, DACs, and ADCs. Although only one antenna is shown in the figures, the terminal may have multiple antennas. Furthermore, the RF processor may include multiple RF chains.

[0485] The baseband processor performs the conversion between baseband signals and bit strings according to the system's PHY standard. For example, during data transmission, the baseband processor generates complex symbols by encoding and modulating the transmitted bit string. Furthermore, during data reception, the baseband processor recovers the received bit string by demodulating and decoding the baseband signal provided from the RF processor. For instance, following the OFDM method, during data transmission, the baseband processor generates complex symbols by encoding and modulating the transmitted bit string, performs mapping of the complex symbols to subcarriers, and then configures the OFDM symbols through IFFT operations and CP insertion. Furthermore, during data reception, the baseband processor divides the baseband signal provided from the RF processor into units of OFDM symbols, recovers the signal mapped to the subcarriers through FFT operations, and then recovers the received bit string through demodulation and decoding.

[0486] The baseband processor and RF processor can transmit and receive signals as described above. Therefore, the baseband processor and RF processor can be referred to as a transmitter, receiver, transceiver, or communication unit. Furthermore, to support different radio connection technologies, at least one of the baseband processor and RF processor may include multiple communication modules. Additionally, to process signals in different frequency bands, at least one of the baseband processor and RF processor may include different communication modules.

[0487] The storage unit stores data related to the basic programs, applications, and configuration information used for terminal operation. The storage unit provides the stored data based on requests from the controller.

[0488] The controller controls the overall operation of the terminal. For example, the controller transmits and receives signals via a baseband processor and an RF processor. Furthermore, the controller records data in or reads data from a storage unit. Additionally, the controller controls the suspension and resumption of operation of the SRB and DRB. For this purpose, the controller may include at least one processor. For example, the controller may include a CP that performs control for communication and a higher-level AP that controls applications such as applications. The controller may include multiple connection processors.

[0489] A base station includes an RF processor, a baseband processor, a backhaul communication unit, a storage unit, and a controller.

[0490] The RF processor performs functions for transmitting and receiving signals over a radio channel, such as signal band conversion and amplification. That is, the RF processor performs up-conversion of baseband signals provided by the baseband processor to RF band signals for transmission to the antenna, and down-conversion of RF band signals received by the antenna back to baseband signals. For example, the RF processor may include transmit filters, receive filters, amplifiers, mixers, oscillators, DACs, and ADCs. Although only one antenna is shown in the figures, the first connection node may accommodate multiple antennas. Furthermore, the RF processor may include multiple RF chains.

[0491] The baseband processor performs the conversion between baseband signals and bit strings according to the PHY standard of the first radio connection technology. For example, during data transmission, the baseband processor generates complex symbols by encoding and modulating the transmitted bit string. Furthermore, during data reception, the baseband processor recovers the received bit string by demodulating and decoding the baseband signal provided from the RF processor. For example, following the OFDM method, during data transmission, the baseband processor generates complex symbols by encoding and modulating the transmitted bit string, performs mapping of the complex symbols to subcarriers, and then configures the OFDM symbols through IFFT operations and CP insertion. Furthermore, during data reception, the baseband processor divides the baseband signal provided from the RF processor into units of OFDM symbols, recovers the signal mapped to the subcarriers through FFT operations, and then recovers the received bit string through demodulation and decoding. The baseband processor and RF processor transmit and receive signals as described above. Therefore, the baseband processor and RF processor can be referred to as a transmitter, receiver, transceiver, or communication unit.

[0492] The backhaul communication unit provides an interface for performing communication with other nodes in the network.

[0493] The storage unit stores basic programs, application programs, and configuration information for the operation of the main base station. Specifically, the storage unit can store information about bearers assigned to connected terminals and measurement results reported from connected terminals. Furthermore, the storage unit can store information that determines whether to provide multiple connections to terminals or suspend multiple connections to terminals. Additionally, the storage unit provides stored data based on requests from the controller.

[0494] The controller controls the overall operation of the main base station. For example, the controller transmits and receives signals via a baseband processor and an RF processor or via a backhaul communication unit. Furthermore, the controller records data in or reads data from a storage unit. For this purpose, the controller may include at least one processor. For example, the controller may include multiple connection processors.

[0495] Although this disclosure has been shown and described with reference to various embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of this disclosure as defined by the claims and their equivalents.

Claims

1. A method executed by a terminal, the method comprising: Send capability information associated with Time Division Multiplexing (TDM) operations to the first base station; Receive a Radio Resource Control (RRC) connection reconfiguration message from the first base station, which includes a TDM mode associated with the dual-connection DC of the first and second base stations, wherein the TDM mode is used when power control requires a single uplink transmission; In response to receiving an RRC connection reconfiguration message, a timer is started; The random access procedure to the second base station is executed based on the timer; If the random access procedure is successful before the timer expires, a first message is sent to the first base station, indicating that the random access procedure is complete. as well as The uplink transmission based on the first information is performed using TDM mode. Specifically, when the terminal transmits data using TDM mode on the first frequency of the first base station, the terminal does not transmit data on the second frequency of the second base station. The TDM mode indicates the time allowed for transmission by a terminal configured with Evolved Universal Terrestrial Radio Access - New Radio (EN) - DC.

2. The method as described in claim 1, wherein, The uplink transmission is performed in a subframe for either the first base station or the second base station using TDM mode.

3. The method of claim 1, further comprising: If the random access procedure fails before the timer expires, a second message is sent to the first base station, indicating a second message indicating the failure of the random access procedure. and Based on the transmission of the second information, uplink transmission is performed without using the TDM mode.

4. The method of claim 1, wherein, The first base station corresponds to a Long Term Evolution (LTE) base station, and the second base station corresponds to a New Radio (NR) base station.

5. The method of claim 1, wherein, The TDM mode is determined based on the terminal's Quality of Service (QoS) or service, and The TDM mode includes information about duration, information about period, and information about offset.

6. A terminal, comprising: transceiver; and The controller, coupled to the transceiver, is configured to: Send capability information associated with Time Division Multiplexing (TDM) operations to the first base station. Receives a Radio Resource Control (RRC) connection reconfiguration message from a first base station, including a TDM mode associated with a dual-connectivity DC of the first and second base stations, wherein the TDM mode is used when power control requires a single uplink transmission. In response to receiving an RRC connection reconfiguration message, a timer is started; The random access procedure to the second base station is executed based on the timer; If the random access procedure is successful before the timer expires, a first message is sent to the first base station, indicating that the random access procedure is complete. as well as The uplink transmission based on the first information is performed using TDM mode. Specifically, when the terminal transmits data using TDM mode on the first frequency of the first base station, the terminal does not transmit data on the second frequency of the second base station. The TDM mode indicates the time allowed for transmission by a terminal configured with Evolved Universal Terrestrial Radio Access - New Radio (EN) - DC.

7. The terminal as described in claim 6, wherein, The uplink transmission is performed in a subframe for either the first base station or the second base station using TDM mode.

8. The terminal as described in claim 6, wherein, The control is also configured to: If the random access procedure fails before the timer expires, a second message is sent to the first base station, indicating that the random access procedure has failed. and Based on the transmission of the second information, uplink transmission is performed without using the TDM mode.

9. The terminal as described in claim 6, wherein, The first base station corresponds to a Long Term Evolution (LTE) base station, and the second base station corresponds to a New Radio (NR) base station.

10. The terminal as claimed in claim 6, wherein, The TDM mode is determined based on the terminal's Quality of Service (QoS) or service, and The TDM mode includes information about duration, information about period, and information about offset.

11. A method performed by a first base station, the method comprising: Receive capability information associated with Time Division Multiplexing (TDM) operations from the terminal; Send a request message containing information related to TDM operation to the second base station; Receive a response message from the second base station; Send a Radio Resource Control (RRC) connection reconfiguration message to the terminal, which includes a TDM mode associated with the dual-connection DC of the first base station and the second base station, wherein the TDM mode is used when power control requires a single uplink transmission; If the random access procedure is successful before the timer initiated based on the RRC connection reconfiguration message expires, the terminal receives first information indicating that the random access procedure to the second base station is completed. The uplink reception based on the first information is performed using TDM mode. Specifically, when the terminal transmits data on the first frequency of the first base station using TDM mode, the terminal does not transmit data on the second frequency of the second base station. The TDM mode indicates the time allowed for transmission by a terminal configured with Evolved Universal Terrestrial Radio Access - New Radio (EN) - DC.

12. The method of claim 11, wherein, The uplink reception is performed in a subframe for either the first base station or the second base station using TDM mode.

13. The method as described in claim 11, in, The first base station corresponds to a Long Term Evolution (LTE) base station, and the second base station corresponds to a New Radio (NR) base station.

14. The method of claim 11, wherein, The TDM mode is determined based on the terminal's Quality of Service (QoS) or service, and The TDM mode includes information about duration, information about period, and information about offset.

15. The method of claim 11, further comprising: If the random access procedure fails before the timer started based on the RRC connection reconfiguration message expires, the terminal receives second information indicating that the random access procedure to the second base station has failed. as well as Based on the reception of the second information, uplink reception is performed without using the TDM mode.

16. A first base station, comprising: transceiver; and The controller, coupled to the transceiver, is configured to: Receive capability information associated with Time Division Multiplexing (TDM) operations from the terminal. Send a request message to the second base station, including information associated with the TDM operation. Receive a response message from the second base station. The terminal is sent a Radio Resource Control (RRC) connection reconfiguration message including a TDM mode associated with the dual-connectivity DC of the first and second base stations, wherein the TDM mode is used when power control requires a single uplink transmission. If the random access procedure succeeds before the timer initiated based on the RRC connection reconfiguration message expires, the terminal receives first information indicating that the random access procedure to the second base station has been completed. The uplink reception based on the first information is performed using TDM mode. Specifically, when the terminal transmits data on the first frequency of the first base station using TDM mode, the terminal does not transmit data on the second frequency of the second base station. The TDM mode indicates the time allowed for transmission by a terminal configured with Evolved Universal Terrestrial Radio Access - New Radio (EN) - DC.

17. The first base station as described in claim 16, wherein, The uplink reception is performed in a subframe for either the first base station or the second base station using TDM mode.

18. The first base station as described in claim 16, in, The first base station corresponds to a Long Term Evolution (LTE) base station, and the second base station corresponds to a New Radio (NR) base station.

19. The first base station as described in claim 16, wherein, The TDM mode is determined based on the terminal's Quality of Service (QoS) or service, and The TDM mode includes information about duration, information about period, and information about offset.

20. The first base station as described in claim 16, wherein, The controller is also configured to: If the random access procedure fails before the timer for the procedure initiated based on the RRC connection reconfiguration message expires, the terminal receives second information indicating that the random access procedure for the second base station has failed. as well as Based on the reception of the second information, uplink reception is performed without using the TDM mode.

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