Method and apparatus for supporting multiple secondary cell group configuration in dual connectivity supported by next generation mobile communication system

Abstract

The disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system beyond 4th-Generation (4G) systems with IoT technologies. The disclosure can be applied to intelligent services based on the 5G communication technology and IoT-related technologies, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. A method performed by a terminal in a communication system is provided. The method includes receiving, from a first base station, configuration information for a secondary cell group (SCG) including at least one serving cell associated with a second base station; receiving, from the first base station, a first message for activating or deactivating the SCG; and in case that the SCG is deactivated based on the first message and uplink data arrives for at least one bearer of the SCG, transmitting a second message for activating the SCG. According to the disclosure, carrier aggregation and dual connectivity can be activated quickly, thereby reducing battery consumption of the terminal.

Description

TECHNICAL FIELD

[0001] The disclosure relates to operations of a terminal and a base station in a mobile communication system.

[0002] More specifically, the disclosure relates to a method and apparatus for efficiently operating carrier aggregation (CA) or dual connectivity (DC) in a next-generation mobile communication system. BACKGROUND

[0003] To meet the demand for wireless data traffic having increased since deployment of fourth generation (4G) communication systems, efforts have been made to develop an improved fifth generation (5G) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a 'Beyond 4G Network' or a 'Post long term evolution (LTE) System'. The 5G communication system is considered to be implemented in higher frequency (millimeter (mm) wave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, analog beam forming, large scale antenna techniques are discussed in 5G communication systems. In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), reception-end interference cancellation and the like. In the 5G system, hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) frequency modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), filter bank multi-carrier (FBMC), a non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as an advanced access technology have been developed.

[0004] The Internet, which is a human centered connectivity network where humans generate and consume information, is now evolving to the Internet of Things (IoT) where distributed entities, such as things, exchange and process information without human intervention. The Internet of Everything (IoE), which is a combination of the IoT technology and the Big data processing technology through connection with a cloud server, has emerged as a new paradigm for the IoT technology. As the technology elements, such as "sensing technology", "wired / wireless communication and network infrastructure", "service interface technology", and "security technology" have been demanded for IoT implementation, a sensor network, a Machine-to-Machine (M2M) communication, Machine Type Communication (MTC), and so forth have been researched. Such an IoT environment can provide intelligent Internet technology services that create a new value through collection and analysis of data generated from connected things. The IoT can be applied to a variety of fields including smart home, smart building, smart city, smart car or connected cars, smart grid, health care, smart appliances, and advanced medical services through the convergence and combination of existing Information Technology (IT) and various industrial applications.

[0005] In line with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as a sensor network, Machine Type Communication (MTC), and Machine-to-Machine (M2M) communication can be implemented by beamforming, MIMO, and array antennas. Application of a cloud Radio Access Network (RAN) as the above-described Big data processing technology can also be considered an example of convergence between the 5G technology and the IoT technology.

[0006] There is a need for a method of using carrier aggregation or dual connectivity in a next-generation mobile communication system.

[0007] The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure. SUMMARY

[0008] TECHNICAL PROBLEM

[0009] In a next-generation mobile communication system, carrier aggregation (CA) or dual connectivity (DC) can be used to provide a terminal with a service having a high data transmission rate and a low transmission delay.

[0010] A method for preventing a processing delay that can occur when a carrier aggregation or dual connectivity is configured and activated for a terminal connected to a network or when the carrier aggregation or dual connectivity is used and then deactivated is needed. If a terminal maintains a plurality of cells active to use a carrier aggregation or dual connectivity, the terminal needs to perform physical downlink control channel (PDCCH) monitoring for each cell, and thus battery consumption of the terminal can be great. On the other hand, if a plurality of cells are maintained deactivated to reduce battery consumption of the terminal, a data transmission delay or a data reception delay can occur due to a delay that occurs when the plurality of cells are activated to use the carrier aggregation or dual connectivity.

[0011] In the above or the present disclosure, a cell can refer to a primary cell (PCell), a secondary cell (SCell) (e.g., an SCell configured in a master cell group (MCG)), a primary secondary cell (PSCell) (e.g., a PCell of a secondary cell group (SCG)), or an SPCell (e.g., an SCell configured in a secondary cell group (SCG)).

[0012] Solution to the problem

[0013] Aspects of the disclosure are to address at least the above-mentioned problems and / or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the disclosure is to provide a next-generation mobile communication system, a carrier aggregation (CA), or a dual connectivity (DC) that can be used to provide a terminal with a service having a high data transmission rate and a low transmission delay.

[0014] Additional aspects will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following description and / or can be learned by practice of the presented embodiments.

[0015] According to an aspect of the disclosure, a method performed by a terminal in a communication system is provided. The method includes receiving, from a first base station, configuration information for a secondary cell group (SCG) including at least one serving cell associated with a second base station, receiving, from the first base station, a first message for activating or deactivating the SCG, and in case that the SCG is deactivated based on the first message and uplink data arrives at at least one bearer of the SCG, transmitting a second message for activating the SCG.

[0016] According to another aspect of the disclosure, a method performed by a terminal in a communication system is provided. The method includes receiving, from a first base station, configuration information for an SCG including at least one serving cell associated with a second base station, receiving, from the first base station, a first message for activating or deactivating the SCG, and in case that the SCG is deactivated based on the first message and uplink data arrives at at least one bearer of the SCG, transmitting, to the first base station, a second message for activating the SCG.

[0017] According to another aspect of the disclosure, a terminal in a communication system is provided. The terminal includes a transceiver and a controller configured to control to receive, from a first base station via the transceiver, configuration information for an SCG including at least one serving cell associated with a second base station, receive, from the first base station via the transceiver, a first message for activating or deactivating the SCG, and in case that the SCG is deactivated based on the first message and uplink data arrives at at least one bearer of the SCG, transmit, to the first base station via the transceiver, a second message for activating the SCG.

[0018] According to another aspect of the disclosure, a method performed by a base station in a communication system is provided. The base station includes a transceiver and a controller configured to control to transmit, to a terminal via the transceiver, configuration information for an SCG including at least one serving cell associated with a second base station, transmit, to the terminal via the transceiver, a first message for activating or deactivating the SCG, and in case that the SCG is deactivated based on the first message and uplink data arrives at at least one bearer of the SCG, receive, from the terminal via the transceiver, a second message for activating the SCG.

[0019] Advantages of the Invention

[0020] The disclosure proposes a new mode enabling a terminal in a radio resource control (RRC) connected mode that has established a connection with a network to quickly activate and deactivate a carrier aggregation or a dual connectivity in a next-generation mobile communication system, the new mode including a hibernation mode, a suspend mode, or a deactivation mode. In the disclosure, by proposing a method capable of operating a hibernation (hibernation, dormancy, or suspend) mode at a bandwidth part level, a cell level, or a cell group level (e.g., for a secondary cell group), the terminal can quickly activate a carrier aggregation or a dual connectivity, and can reduce battery consumption.

[0021] Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conduction with the annexed drawings, discloses various embodiments of the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0022] The above and other aspects, features and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0023] Figure 1 FIG. 1 is a diagram illustrating a structure of a long term evolution (LTE) system according to an embodiment of the disclosure;

[0024] Figure 2 FIG. 2 is a diagram illustrating a radio protocol structure in an LTE system according to an embodiment of the disclosure;

[0025] Figure 3 FIG. 3 is a diagram illustrating a structure of a next generation mobile communication system according to an embodiment of the disclosure;

[0026] Figure 4 FIG. 4 is a diagram illustrating a radio protocol structure of a next generation mobile communication system according to an embodiment of the disclosure;

[0027] Figure 5 FIG. 5 is a diagram illustrating a procedure of providing a service to a UE by efficiently using a wide frequency bandwidth in a next generation mobile communication system according to an embodiment of the disclosure;

[0028] Figure 6 FIG. 6 is a diagram illustrating a procedure of switching a user equipment (UE) from an RRC idle mode to an RRC connected mode and a method of configuring a plurality of bandwidth parts (BWPs) and configuring a default bandwidth part (default BWP) or a first active bandwidth part (first active BWP) in a next generation mobile communication system according to an embodiment of the disclosure;

[0029] Figure 7 FIG. 7 is a diagram illustrating a bandwidth part specific state transition procedure or a bandwidth part switching procedure according to an embodiment of the disclosure;

[0030] Figure 8 FIG. 8 is a diagram illustrating a discontinuous reception (DRX) configuration or a DRX operation method capable of saving battery power of a UE according to an embodiment of the disclosure;

[0031] Figure 9 FIG. 9 is a diagram illustrating a method of operating a dormant bandwidth part in an activated SCell according to an embodiment of the disclosure;

[0032] Figure 10 FIG. 10 is a diagram illustrating a first embodiment of a method of operating a dormant bandwidth part in an activated SCell according to an embodiment of the disclosure; Figure 9

[0033] FIG. 11 is a diagram illustrating a second embodiment of a method of operating a dormant bandwidth part in an activated SCell according to an embodiment of the disclosure; Figure 11 Figure 9 FIG. 12 is a diagram illustrating a third embodiment of a method of operating a dormant bandwidth part in an activated SCell according to an embodiment of the disclosure.​

[0034] Figure 12 is a diagram illustrating implementation of a reference Figure 9 a diagram describing a third embodiment of a method of operating a dormant bandwidth part in an activated SCell according to an embodiment of the disclosure;

[0035] Figure 13 is a diagram illustrating a fourth embodiment according to an embodiment of the disclosure in which the first embodiment, the second embodiment, or the third embodiment is extended and applied to a UE in an RRC inactive mode;

[0036] Figure 14 is a diagram illustrating a medium access control (MAC) control information (MAC control element, MAC CE) indicating a state transition to an active state, a dormant state, or a deactivated state according to an embodiment of the disclosure;

[0037] Figure 15 is a diagram illustrating a first signaling procedure of configuring or releasing dual connectivity, or configuring, releasing, activating, resuming, suspending, or deactivating a secondary cell group configured with dual connectivity according to an embodiment of the disclosure;

[0038] Figure 16 is a diagram illustrating a second signaling procedure of configuring or releasing dual connectivity, or configuring, releasing, activating, resuming, suspending, or deactivating a secondary cell group configured with dual connectivity according to an embodiment of the disclosure;

[0039] Figure 17 is a diagram illustrating a third signaling procedure of configuring or releasing dual connectivity, or configuring, releasing, activating, resuming, suspending, or deactivating a secondary cell group configured with dual connectivity according to an embodiment of the disclosure;

[0040] Figure 18 is a diagram illustrating operation of a UE according to an embodiment of the disclosure;

[0041] Figure 19 is a block diagram illustrating a structure of a UE in a communication system according to an embodiment of the disclosure; and

[0042] Figure 20 is a block diagram illustrating a structure of a base station in a communication system according to an embodiment of the disclosure.

[0043] In all the drawings, like reference numerals will be understood to refer to like parts, components, and structures. DETAILED DESCRIPTION

[0044] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be taken as illustrative only. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions can be omitted for clarity and conciseness.

[0045] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but are merely used to enable a clear and consistent understanding of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purpose only and not for limiting the present disclosure as defined by the appended claims and their equivalents.

[0046] It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0047] In the following description of the present disclosure, detailed descriptions of related known functions or configurations incorporated herein can be omitted when it can make the subject matter of the present disclosure unnecessarily unclear. The terms to be described below are terms defined in consideration of functions in the present disclosure, and can vary according to users, user intentions, or habits. Therefore, the definition of the terms should be based on the content of the entire specification.

[0048] In describing the present disclosure below, detailed descriptions of related known functions or configurations incorporated herein can be omitted when it can make the subject matter of the present disclosure unnecessarily unclear. Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0049] In the following description, for convenience of explanation, terms for identifying access nodes, terms related to network entities, terms related to messages, terms related to interfaces between network entities, terms related to various identification information, and the like are illustratively used. Accordingly, the present disclosure is not limited to the terms used below, and other terms related to the subject matter having equivalent technical meanings can be used.

[0050] In the following description, for convenience of description, terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) standard will be used to describe the present disclosure. However, the present disclosure is not limited to these terms and names, and can be applied in the same manner to systems conforming to other standards. In the present disclosure, for convenience of description, the term "eNB" can be used interchangeably with the term "gNB". That is, a base station described as "eNB" can indicate "gNB".

[0051] Figure 1 is a diagram illustrating a structure of a long term evolution (LTE) system according to an embodiment of the present disclosure.

[0052] Reference Figure 1 As illustrated, a radio access network of the LTE system includes next generation base stations (evolved node Bs, hereinafter eNBs, node Bs, or base stations) 1-05, 1-10, 1-15, and 1-20, a mobility management entity (MME) 1-25, and a serving-gateway (S-GW) 1-30. A user terminal (user equipment, hereinafter UE or terminal) 1-35 accesses an external network via the eNBs 1-05 to 1-20 and the S-GW 1-30.

[0053] Reference Figure 1 The eNBs 1-05 to 1-20 correspond to existing node Bs of a universal mobile telecommunications system (UMTS) system. The eNBs are connected to the UEs 1-35 via radio channels, and perform more complex tasks than the existing node Bs. In the LTE system, because all user traffic including real-time services such as voice over IP (VoIP) is serviced via shared channels, a device that collects state information such as a buffer state of the UE, an available transmission power state, and a channel state in order to perform scheduling is required, and the eNBs 1-05 to 1-20 assume the role of the device. A single eNB generally controls multiple cells. For example, in order to implement a transmission rate of 100 Mbps, the LTE system uses, for example, orthogonal frequency division multiplexing (hereinafter OFDM) as a radio access technology in a 20 MHz bandwidth. An adaptive modulation and coding (hereinafter AMC) method that determines a modulation scheme and a channel coding rate according to a channel state of the UE is applied. The S-GW 1-30 is a device configured to provide a data bearer, and generates or removes a data bearer under the control of the MME 1-25. The MME is a device responsible for various control functions as well as a mobility management function of the UE, and is connected to multiple base stations.

[0054] Figure 2 is a diagram illustrating a radio protocol structure in the LTE system according to an embodiment of the present disclosure.

[0055] Reference Figure 2Radio protocols of the LTE system include a packet data convergence protocol (PDCP) 2-05 and 2-40, a radio link control (RLC) 2-10 and 2-35, and a medium access control (MAC) 2-15 and 2-30 in the UE and the eNB, respectively. The packet data convergence protocol (PDCP) 2-05 and 2-40 is responsible for operations such as IP header compression / restoration. The main functions of the PDCP are summarized as follows.

[0056] - header compression and decompression function (robust header compression (ROHC) only)

[0057] - user data transfer function (user data transfer)

[0058] - in-sequence delivery function (in-sequence delivery of upper layer protocol data units (PDUs) in PDCP re-establishment procedure for radio link controller (RLC) acknowledged mode (AM))

[0059] - reordering function (for split bearers of DC (RLC AM only): PDCP PDU routing for transmission and PDCP PDU reordering for reception)

[0060] - duplicate detection function (duplicate detection of lower layer service data units (SDUs) in PDCP re-establishment procedure for RLC AM)

[0061] - retransmission function (for RLC AM: retransmission of PDCP SDUs at handover, and for split bearers of DC, retransmission of PDCP PDUs in PDCP data recovery procedure)

[0062] - ciphering and deciphering function (ciphering and deciphering)

[0063] - timer-based SDU discard function (timer-based SDU discard in uplink)

[0064] Radio Link Control (hereinafter referred to as RLC) 2-10 and 2-35 reconfigures PDCP protocol data units (PDUs) or RLC service data units (SDUs) to appropriate sizes to perform an automatic repeat request (ARQ) operation, etc. The main functions of the RLC are summarized as follows.

[0065] - Data transfer function (transfer of upper layer PDUs)

[0066] - ARQ function (error correction through ARQ (only for AM data transfer))

[0067] - Concatenation, segmentation, and reassembly function (concatenation, segmentation, and reassembly of RLC SDUs (only for unacknowledged mode (UM) and AM data transfer))

[0068] - Re-segmentation function (re-segmentation of RLC data PDUs (only for AM data transfer))

[0069] - Reordering function (reordering of RLC data PDUs (only for UM and AM data transfer))

[0070] - Duplicate detection function (duplicate detection (only for UM and AM data transfer))

[0071] - Error detection function (protocol error detection (only for AM data transfer))

[0072] - RLC SDU discard function (RLC SDU discard (only for UM and AM data transfer))

[0073] - RLC re-establishment function (RLC re-establishment)

[0074] The MAC 2-15 and 2-30 is connected to multiple RLC layers configured in one UE, multiplexes RLC PDUs into a MAC PDU, and demultiplexes RLC PDUs from a MAC PDU. The main functions of the MAC are summarized as follows.

[0075] - Mapping function (mapping between logical channels and transport channels)

[0076] - Multiplexing and demultiplexing function (multiplexing of MAC SDUs belonging to one or different logical channels into transport blocks (TBs) delivered to the physical layer on transport channels / demultiplexing of MAC SDUs belonging to one or different logical channels from transport blocks (TBs) delivered to the physical layer on transport channels)

[0077] - Scheduling information reporting function (scheduling information reporting)

[0078] - Hybrid automatic repeat request (HARQ) function (error correction through HARQ)

[0079] - Function of priority handling between logical channels (priority handling between logical channels of one UE)

[0080] - Function of priority handling between UEs (priority handling between UEs in a manner of dynamic scheduling)

[0081] - Multimedia Broadcast Multicast Service (MBMS) service identification function (MBMS service identification)

[0082] - Transport format selection function (transport format selection)

[0083] - Padding function (padding)

[0084] The physical layer 2-20 and 2-25 performs channel coding and modulation of upper layer data, makes the channel-coded and modulated upper layer data into OFDM symbols, and transmits the OFDM symbols via a radio channel, or performs demodulation and channel decoding of the OFDM symbols received through the radio channel and delivers them to the upper layer.

[0085] Figure 3 is a diagram showing the structure of a next-generation mobile communication system according to an embodiment of the disclosure.

[0086] Referring to Figure 3 As illustrated, a radio access network (hereinafter, new radio (NR) or 5G) of a next-generation mobile communication system includes a next-generation base station (new radio node B, hereinafter, NR gNB or NR base station) 3-10 and a new radio core network (NR CN) 3-05. A user terminal (new radio user equipment, hereinafter, NR UE or terminal) 3-15 accesses an external network via the NR gNB 3-10 and the NR CN 3-05.

[0087] Referring to Figure 3, NR gNB 3-10 corresponds to an evolved Node B (eNB) (e.g., eNB 3-30) of the existing LTE system. The NR gNB 3-10 is connected to the NR UE 3-15 via a radio channel, and can provide more superior services compared to the existing Node B within the cell 3-20. In the next-generation mobile communication system, since all user traffic is provided via a shared channel, a device that collects state information such as a buffer state of a UE, an available transmission power state, and a channel state in order to perform scheduling is required, and the NR gNB 3-10 takes the role of the device. A single NR gNB 3-10 generally controls multiple cells. In order to implement ultra-high speed data transmission compared to the current LTE, an existing maximum bandwidth or a larger bandwidth is available, and by using orthogonal frequency division multiplexing (hereinafter, OFDM) as a radio access technology, beamforming can be additionally combined. An adaptive modulation and coding (hereinafter, AMC) method of determining a modulation scheme and a channel coding rate according to a channel state of a UE is applied. The NR CN 3-05 performs functions such as mobility support, bearer configuration, and quality of service (QoS) configuration. The NR CN 3-05 is a device responsible for various control functions as well as a mobility management function of a UE, and is connected to multiple base stations. The next-generation mobile communication system can be linked to the existing LTE system, and the NR CN 3-05 is connected to the MME 3-25 via a network interface. The MME 3-25 is connected to the eNB 3-30, which is an existing base station.

[0088] Figure 4 is a diagram illustrating a radio protocol structure of a next-generation mobile communication system according to an embodiment of the disclosure.

[0089] Referring to Figure 4 , the radio protocol of the next-generation mobile communication system includes NR SDAPs 4-01 and 4-45, NR PDCPs 4-05 and 4-40, NR RLCs 4-10 and 4-35, and NR MACs 4-15 and 4-30 in the UE and the NR base station, respectively.

[0090] The main functions of the NR SDAPs 4-01 and 4-45 can include some of the following functions.

[0091] - User data transfer function (transfer of user plane data)

[0092] - Function for mapping QoS flow and data bearer for uplink and downlink (mapping between QoS flow and data radio bearer (DRB) for DL and UL)

[0093] - Function of marking QoS flow ID in uplink and downlink (marking QoS flow ID in DL and UL packets)

[0094] - Function of mapping reflective QoS flow to data bearer for uplink SDAP PDU (mapping of reflective QoS flow for UL SDAP PDU to DRB)

[0095] - With respect to the SDAP layer, the UE can be configured via an RRC message whether to use a header of the SDAP layer or a function of the SDAP layer for each PDCP layer, for each bearer, or for each logical channel, and if the SDAP header is configured, the UE can be instructed to update or reconfigure mapping information for data bearers and QoS flows in uplink and downlink by a non-access stratum (NAS) reflective QoS 1-bit indicator (NAS reflective QoS) and an AS reflective QoS 1-bit indicator (AS reflective QoS) in the SDAP header. The SDAP header can include QoS flow ID information indicating QoS. The QoS information can be used as data processing priority, scheduling information, etc. to support a smooth service.

[0096] The main functions of the NR PDCP 4-05 and 4-40 can include some of the following functions.

[0097] - Header compression and decompression function (ROHC only)

[0098] - User data transfer function (transfer of user data)

[0099] - In-sequence delivery function (in-sequence delivery of upper layer PDUs)

[0100] - Out-of-sequence delivery function (out-of-sequence delivery of upper layer PDUs)

[0101] - Reordering function (reordering of received PDCP PDUs)

[0102] - Duplicate detection function (duplicate detection of lower layer SDUs)

[0103] - Re-transmission function (retransmission of PDCP SDUs)

[0104] - Encryption and deciphering function (encryption and deciphering)

[0105] - Timer-based SDU discard function (timer-based SDU discard in uplink)

[0106] The reordering function of the NR PDCP device refers to a function of reordering PDCP PDUs received at a lower layer in sequence based on a PDCP sequence number (SN), and can include a function of delivering data to an upper layer in the order of reordering, or can include a function of delivering data directly without considering the order, can include a function of reordering the order and recording missing PDCP PDUs, can include a function of reporting a status of missing PDCP PDUs to a transmitter, and can include a function of requesting retransmission of missing PDCP PDUs.

[0107] The main functions of the NR RLC 4-10 and 4-35 can include some of the following functions.

[0108] - Data transmission function (transfer of upper layer PDU)

[0109] - In-sequence delivery function (in-sequence delivery of upper layer PDU)

[0110] - Out-of-sequence delivery function (out-of-sequence delivery of upper layer PDU)

[0111] - ARQ function (error correction through ARQ)

[0112] - Concatenation, segmentation, and reassembly function (concatenation, segmentation, and reassembly of RLC SDU)

[0113] - Re-segmentation function (re-segmentation of RLC data PDU)

[0114] - Reordering function (reordering of RLC data PDU)

[0115] - Duplicate detection function (duplicate detection)

[0116] - Error detection function (protocol error detection)

[0117] - RLC SDU discard function (RLC SDU discard)

[0118] - RLC re-establishment function (RLC re-establishment)

[0119] The in-sequence delivery function of the NR RLC device refers to a function of delivering RLC SDUs received from a lower layer to an upper layer in sequence, and can include a function of reassembling and delivering divided RLC SDUs when an initially one RLC SDU is divided into a plurality of RLC SDUs and then received, a function of rearranging received RLC SDUs based on an RLC sequence number (SN) or a PDCP sequence number (SN), a function of rearranging the order and recording missing RLC SDUs, a function of reporting a status of missing RLC SDUs to a transmitter, a function of requesting retransmission of missing RLC SDUs, and a function of delivering only RLC SDUs before missing RLC SDUs to an upper layer in sequence when there are missing RLC SDUs. Alternatively, the in-sequence delivery function can include a function of delivering all RLC SDUs received before a predetermined timer has expired to an upper layer in sequence although there are missing RLC SDUs, or a function of delivering all RLC SDUs received until a current time to an upper layer in sequence although there are missing RLC SDUs if the predetermined timer has expired. The RLC PDU can be processed in the order in which it is received (in the order of arrival regardless of the order of the sequence number or the number) and can be delivered to the PDCP device regardless of the order (out-of-sequence delivery). In the case of segmentation, a segment stored in a buffer or to be received later can be received, reconfigured into one complete RLC PDU, processed, and then can be delivered to the PDCP device. The NR RLC layer can not include a splicing function, and the function can be performed in the NR MAC layer or can be replaced with a multiplexing function of the NR MAC layer.

[0120] The out-of-sequence delivery function of the NR RLC device refers to a function of delivering RLC SDUs received from a lower layer to an immediately higher layer in any order, can include a function of reassembling and delivering divided RLC SDUs when an initially one RLC SDU is divided into a plurality of RLC PDUs and then received, and can include a function of storing RLC SNs or PDCP SNs of received RLC PDUs, rearranging the order thereof, and recording missing RLC PDUs.

[0121] The NR MACs 4-15 and 4-30 can be connected to a plurality of NR RLC layers configured for one UE, and the main functions of the NR MAC can include some of the following functions.

[0122] - Mapping function (mapping between logical channel and transport channel)

[0123] - multiplexing and demultiplexing function (multiplexing / demultiplexing of MAC SDUs)

[0124] - scheduling information reporting function (scheduling information reporting)

[0125] - HARQ function (error correction through HARQ)

[0126] - function of priority handling between logical channels (priority handling between logical channels of one UE)

[0127] - function of priority handling between UEs (priority handling between UEs in a manner of dynamic scheduling)

[0128] - MBMS service identification function (MBMS service identification)

[0129] - transport format selection function (transport format selection)

[0130] - padding function (padding)

[0131] The NR PHY layer 4-20 and 4-25 can perform channel coding and modulation of upper layer data, make OFDM symbols of the channel-coded and modulated upper layer data, and transmit the OFDM symbols via a radio channel, or the NR PHY layer 4-20 and 4-25 can perform demodulation and channel decoding of OFDM symbols received through a radio channel, and deliver them to an upper layer.

[0132] The next-generation mobile communication system can use a very high frequency band, and thus the frequency bandwidth can also be very wide. However, supporting all very wide bandwidths in UE implementation requires very high implementation complexity and results in very high cost. Therefore, in the next-generation mobile communication system, the concept of a bandwidth part (BWP) can be introduced, in which a base station can configure multiple bandwidth parts for one cell (SPCell or SCell) configured for a UE, and the UE can transmit or receive data in one or more bandwidth parts.

[0133] In the disclosure, when a dormant bandwidth part (dormant BWP) proposed in the disclosure is introduced, specific operations for state transition (transfer) or bandwidth part switching are proposed in consideration of the state of an SCell and multiple bandwidth parts configured for the SCell. The disclosure proposes each of the bandwidth part state transition or the bandwidth part switching by managing the dormant mode at the bandwidth part level, and proposes a specific bandwidth part operation according to the state of each SCell or the state or mode (active, deactivated, or dormant) of each bandwidth part.

[0134] In the disclosure, multiple bandwidth parts are configured for one cell (SPCell, PCell, PSCell, or SCell) per downlink or uplink, and operations can be performed by switching the bandwidth parts to an active bandwidth part (active DL BWP or active UL BWP), a dormant bandwidth part (dormant BWP or dormant DL BWP), or an inactive bandwidth part (inactive DL BWP or inactive UL BWP) (or a deactivated DL BWP or a deactivated UL BWP). That is, for one cell, by shifting a downlink bandwidth part or an uplink bandwidth part to an active state (alternatively, by switching to an active bandwidth part), a data transmission rate can be increased in a method similar to carrier aggregation. Also, by shifting a downlink bandwidth part to a dormant state (or switching to a dormant bandwidth part), a UE can not perform PDCCH monitoring for the cell, thereby saving battery power. In this case, the UE can perform channel measurement on the downlink bandwidth part, and can report the channel measurement result so that fast activation of the cell or the bandwidth part can be supported later. Battery power of the UE can be saved by shifting a downlink (or uplink) bandwidth part to an inactive state in one cell. State transition per bandwidth part or bandwidth part switching per cell can be configured and indicated via a radio resource control (RRC) message, a medium access control (MAC) control element (CE), or downlink control information (DCI) of a PDCCH. The dormant bandwidth part can also be extended and applied to dual connectivity. For example, the dormant bandwidth part can be applied to a PSCell of a secondary cell group. As another method, the dormant bandwidth part is extended to the concept of cell group suspension or cell group deactivation, and the cell group suspension or cell group deactivation is indicated to one cell group (for example, a secondary cell group) for which dual connectivity has been configured to the UE, so that the UE can reduce its power consumption by suspending data transmission or reception, suspending PDCCH monitoring, or intermittently performing PDCCH monitoring based on a very long period in the indicated cell group. When the cell group suspension or deactivation is indicated to the UE, the UE can perform channel measurement in the cell group for which the cell group suspension or deactivation has been indicated, and can report the channel measurement result to the network (for example, to a primary cell group or a secondary cell group) in order to support fast activation of dual connectivity. With regard to the cell group for which the cell group suspension or deactivation has been indicated, the UE performs procedures as described above, and in this case, the UE can maintain and store cell group configuration information without discarding (or flushing) the information, and when a cell group activation or recovery indication is received from the network, the UE can restore the cell group configuration information. For example, cell group configuration information (for example, configuration information of each of PDCP, RLC, or MAC layers, bearer configuration information, or cell-specific configuration information) configured for the UE can be stored or maintained as is.If the UE receives a cell group resume or activation indication for a cell group for which cell group suspension or deactivation has been indicated, the UE can resume, recover, or re-apply configuration information of the cell group (operate according to the cell group configuration information). In this case, a bearer can be resumed, data transmission or reception can be resumed, PDCCH monitoring can be resumed, channel measurement reporting can be performed, or periodically configured transmission resources can be reactivated.

[0135] First channel measurement configuration information (e.g., configuration information for channel state information reference signals (CSI-RS), synchronization signal blocks (SSB), or radio resources or reference signals (RS)) for fast activation of a cell group can be included in cell group configuration information, previously configured cell group configuration information, or a message (e.g., an RRC message or an RRCReconfiguration message) indicating cell group activation or resumption, in order to configure a UE. As another method, first channel measurement configuration information (e.g., configuration information for channel state information reference signals (CSI-RS), synchronization signal blocks (SSB), or radio resources or reference signals (RS)) for fast activation of a cell group can be included in a message (e.g., an RRC message or an RRCReconfiguration message) indicating cell group deactivation, suspension, or release, in order to pre-configure a UE. The first channel measurement configuration information can include information for fast activation of a cell group. For example, cell (e.g., PCell, PSCell, or SCell) configuration information of a cell group can include configuration information enabling a base station to transmit many channel measurement signals or frequently transmit channel measurement signals to enable fast channel measurement in a cell, configuration information can include a period (e.g., a radio resource) of frequent channel measurement signals, transmission resource information (a frequency or time transmission resource via which a frequent channel measurement signal is transmitted), an interval or frequency (a number of times a frequent channel measurement signal is transmitted), a timer value (a time at which a frequent channel measurement signal is transmitted), a time interval (an interval (e.g., a time unit (slot, subframe, symbol, etc.)) at which a frequent channel measurement signal is transmitted), or a transmission resource, period, interval, timing, etc. via which a UE should report a measurement result. The first channel measurement configuration information can not only allow a short reporting period (or transmission resource) in which a UE can report a channel measurement result to be simply configured, but also allow a transmission resource for channel measurement to be configured so that a base station can transmit many channel measurement signals (or transmission resources) or frequently transmit channel measurement signals (or transmission resources) in order to support a UE to perform fast channel measurement or more signal measurement.

[0136] Second channel measurement configuration information (e.g., configuration information for channel state information reference signals (CSI-RS), synchronization signal blocks (SSB), or radio resources or reference signals (RS)) for measuring signals of cells (PSCell, PCell, or SCell) of a cell group can be included in the cell group configuration information, previously configured cell group configuration information, or a message (e.g., an RRC message or an RRCReconfiguration message) indicating activation or resumption of a cell group. Alternatively, second channel measurement configuration information (e.g., configuration information for channel state information reference signals (CSI-RS), synchronization signal blocks (SSB), or radio resources or reference signals (RS)) for measuring signals of cells (PSCell, PCell, or SCell) of a cell group can be included in advance in the cell group configuration information, previously configured cell group configuration information, or a message (e.g., an RRC message or an RRCReconfiguration message) indicating deactivation, suspension, or release of a cell group. The second channel measurement configuration information can include general channel measurement configuration information such as transmission resources, periods, time intervals, or frequencies of channel measurement signals, or transmission resources, periods, or time intervals for channel measurement reporting.

[0137] In the disclosure, the UE can perform channel measurement by applying the first channel measurement configuration information or the second channel measurement configuration information according to the following conditions, and can report the measurement result to the base station.

[0138] -1> if the UE has received a message (e.g., a PDCCH indicator, MAC control information, or an RRC message) indicating activation (or resumption) of a cell (PCell, PSCell, or SCell) or a cell group,

[0139] ■2> if the UE is configured with the first channel measurement configuration information,

[0140] ◆ 3> The UE determines that the base station is to transmit many channel measurement signals or frequently transmit channel measurement signals according to the first channel measurement configuration information, and can temporarily measure many channel measurement signals or frequently measure channel measurement signals according to the first channel measurement configuration information (e.g., until a time interval (e.g., a subframe, a slot, or a symbol) configured in the first channel measurement configuration information, during a specified (or predetermined) time interval, for a certain time (e.g., while a timer is running), or until the first condition is satisfied). In addition, until a time interval (e.g., a subframe, a slot, or a symbol) configured in the first channel measurement configuration information, during a specified (or predetermined) time interval, for a certain time (e.g., while a timer is running), or until the first condition is satisfied, the UE can report the obtained channel measurement result according to the period or transmission resource configured in the first channel measurement configuration information. Accordingly, since the UE is capable of quickly measuring channel measurement signals frequently transmitted from the base station and quickly reporting the measurement result to the base station, a cell (PCell, SCell, or PSCell) or a cell group can be quickly activated (or resumed), or scheduling information can be quickly indicated. If, after the time interval (e.g., a subframe, a slot, or a symbol) configured in the first channel measurement configuration information, after the specified (or predetermined) time interval, after the certain time (e.g., when the timer expires or after the timer expires), or after the first condition is satisfied, the second channel measurement configuration information is configured for the UE, the UE can suspend or release the application of the first channel measurement configuration information, and can measure channel measurement signals according to the second channel measurement configuration information. For example, fallback from the first channel measurement configuration information to the second channel information can be performed, or the second channel information can be applied instead of the first channel measurement configuration information. The obtained channel measurement result can be reported according to the period or transmission resource configured in the second channel measurement configuration information. If the second channel measurement configuration information is not configured, channel measurement can not be performed.

[0141] ■2> Otherwise (if the first channel measurement configuration information is not configured for the UE),

[0142] ◆ 3> If the second channel measurement configuration information is configured for the UE, channel measurement signals can be measured according to the second channel measurement configuration information. The obtained channel measurement result can be reported according to the period or transmission resource configured in the second channel measurement configuration information. If the second channel measurement configuration information is not configured, channel measurement can not be performed.

[0143] The first channel measurement configuration information of the disclosure can be extended, configured, and used in the case of activating or resuming a cell group (e.g., PSCell), activating an SCell, or resuming an RRC connection in an RRC inactive mode.

[0144] The first condition of the present disclosure can be one of the following conditions. Hereinafter, the present disclosure proposes some conditions under which, when a cell is activated, a cell group is activated or resumed, or a UE in an RRC inactive mode resumes connection in RRC connection resume, the base station does not need to transmit an unnecessarily large amount of transmission resources nor an unnecessarily frequent transmission resource. For example, channel measurement or channel measurement reporting can be performed by applying the first channel measurement configuration information until one of the following conditions is met.

[0145] - When the UE successfully completes random access in a cell (e.g., PCell, SCell, or PSCell) or a cell (e.g., PSCell or SCell) of a cell group, when the random access is successfully completed and the first uplink transmission resource is allocated, or when the first uplink transmission resource is indicated to the UE, the UE can determine that the first condition is met.

[0146] ■More specifically, for example, if the UE performs contention-free random access (CFRA) (e.g., if a dedicated preamble or a UE cell identifier (e.g., C-RNTI) is assigned),

[0147] ◆When the UE transmits a dedicated preamble to a cell and receives a random access response (RAR) message or receives an indication of a PDCCH for a random access response, it can be considered that the random access is successfully completed, and thus the UE can determine that the first condition is met. As another method, when the first uplink transmission resource is received after RAR reception, the UE can determine that the first condition is met.

[0148] ■If the UE performs contention-based random access (CBRA) (e.g., if neither a dedicated preamble nor a UE cell identifier (e.g., C-RNTI) is assigned),

[0149] ◆ When the UE transmits a preamble (e.g., a random preamble) to a cell, receives a random access response (RAR) message, transmits a message 3 (e.g., a handover complete message) by using an uplink transmission resource allocated (or included or indicated) in the random access response message, and receives a MAC CE (contention resolution MAC CE) indicating that contention has been resolved from the target base station via message 4, or when an uplink transmission resource is received via a PDCCH corresponding to the C-RNTI of the UE, it can be considered that random access to the target base station has been successfully completed, and the UE can thus determine that the first condition is satisfied. As another method, if the size of the uplink transmission resource allocated in the random access response message is sufficient so that the UE can transmit a message 3 (Msg3) and can additionally transmit uplink data, the UE can determine that the uplink transmission resource is received for the first time, and can determine that the first condition is satisfied. That is, when the RAR is received, the UE can determine that the uplink transmission resource is received for the first time, and can determine that the first condition is satisfied.

[0150] -1> If the UE performs two-step random access (2-step random access) as configured or instructed,

[0151] -1> Or when the UE supports two-step random access in the UE capability even though two-step random access (2-step random access) is not configured or instructed in the message, and when two-step random access is supported in the system information of the cell, and information (e.g., random access resources, a threshold for determining whether to perform two-step random access, etc.) for two-step random access is broadcast in the system information, or when the UE receives the system information, and the UE performs two-step random access for the cell because the signal strength is sufficient or greater than the threshold broadcast in the system information,

[0152] ■2> When two-step random access is successfully completed, the UE can determine that the first condition is satisfied.

[0153] ■2> Two-step random access can be specifically performed by one of contention-based random access (CBRA) or contention-free random access (CFRA).

[0154] ◆3> If the UE performs two-step random access based on CBRA,

[0155] • 4> The UE can transmit a preamble in a transmission resource for two-step random access (e.g., a PRACH occasion, a transmission resource configured by a base station via an RRC message, or a transmission resource broadcasted in system information), and can transmit data (e.g., a MsgA MAC PDU) in a transmission resource for data transmission (e.g., a PUSCH occasion). The data can include a MAC control information (C-RNTI MAC CE) containing a UE identifier (C-RNTI) or an RRC message (RRCReconfigurationComplete message or a handover complete message).

[0156] • 4> The UE can monitor a PDCCH scrambled with a UE identifier (C-RNTI) or a first identifier (MsgB-RNTI) scrambled by a time or a frequency at which the preamble is transmitted.

[0157] • 4> If the UE receives a PDCCH scrambled with a UE identifier, receives an allocation of a downlink transmission resource via the PDCCH, or receives a MAC control information (Timing Advance Command MAC CE) for timing adjustment in the downlink transmission resource,

[0158] • 5> The UE can determine that the two-step random access has been successfully completed, and can determine that the first condition is satisfied.

[0159] • 4> If the UE receives a PDCCH scrambled with a first identifier (MsgB-RNTI), if the UE receives an allocation of a downlink transmission resource via the PDCCH, or if a fallback random access response for a preamble transmitted by the UE is received in a downlink transmission resource, (that is, if a fallback RAR indicating to transmit a MsgA via another transmission resource is received when a base station has received a preamble but failed to receive a MsgA)

[0160] • 5> The UE can transmit data (a MsgA MAC PDU) via a transmission resource indicated in the fallback random access response.

[0161] • 5> The UE can monitor a PDCCH scrambled with a UE identifier (C-RNTI).

[0162] • 5> If the UE receives a PDCCH scrambled with a UE identifier, or receives an allocation of an uplink transmission resource via the PDCCH, the UE can determine that the two-step random access has been successfully completed, and can determine that the first condition is satisfied.

[0163] • 3> If the UE performs a two-step random access based on CFRA,

[0164] • 4> The UE can transmit a preamble in a transmission resource (e.g., a PRACH occasion or a transmission resource designated by a base station via an RRC message) for two-step random access, and can transmit data (e.g., a MsgA MAC PDU) in a transmission resource (e.g., a PUSCH occasion) for data transmission. The data can include a MAC control information (C-RNTI MAC CE) containing a UE identifier (C-RNTI) or an RRC message (RRCReconfigurationComplete message or a handover completion message).

[0165] • 4> The UE can monitor a PDCCH scrambled with a UE identifier (C-RNTI) or a first identifier (MsgB-RNTI) derived from a time or a frequency in which the preamble is transmitted.

[0166] • 4> If the UE receives a PDCCH scrambled with a UE identifier, receives an allocation of a downlink transmission resource via the PDCCH, or receives a MAC control information (Timing Advance Command MAC CE) for timing adjustment in a downlink transmission resource,

[0167] • 5> The UE can determine that the two-step random access has been successfully completed, and can determine that the first condition is satisfied.

[0168] • 4> If the UE receives a PDCCH scrambled with a first identifier (MsgB-RNTI), if the UE receives an allocation of a downlink transmission resource via the PDCCH, or if a fallback random access response for a preamble transmitted by the UE is received in a downlink transmission resource, (that is, if a fallback RAR indicating to transmit a MsgA via another transmission resource is received when a base station has received a preamble but failed to receive a MsgA),

[0169] • 5> The UE can determine that the two-step random access has been successfully completed, and can determine that the first condition is satisfied.

[0170] • 5> The UE can transmit data (a MsgA MAC PDU) via a transmission resource indicated in the fallback random access response.

[0171] -1> The UE can determine that the first condition is satisfied when starting random access or when transmitting a preamble for random access.

[0172] -1> As another method, if two-step random access (2-step random access) is configured or indicated for the UE via a message, the UE can determine that the first condition is satisfied. For example, in the above case, the UE can determine that the first condition is satisfied before starting two-step random access.

[0173] -1> As another method, if the UE is configured or indicated of two-step random access (2-step random access) via a message, and a transmission resource (PUSCH) configured for data transmission in the two-step random access is greater than a first threshold, or if a configured value for timing adjustment (timing advance value) is included in an RRC message, the UE can determine that the first condition is satisfied. The first threshold can be configured by the base station via an RRC message (e.g., RRCReconfiguration message), can be broadcast in system information, or can be configured as a size of data for transmission by the UE. For example, in the above case, the UE can determine that the first condition is satisfied before starting the two-step random access. As another method, if the configured value for timing adjustment (timing advance value) is included in the RRC message, or if the two-step random access is configured, the UE can transmit data directly from the configured transmission resource (e.g., a transmission resource configured via an RRC message, or a transmission resource indicated by a PDCCH of a target base station where the UE monitors the PDCCH) without transmitting a preamble. Accordingly, in the above case, the UE can determine that the first condition is satisfied when transmitting data, or before transmitting data, before starting the two-step random access. As another method, if the configured value for timing adjustment (timing advance value) is included in the RRC message, or if the two-step random access is configured, the UE can transmit data directly via the configured transmission resource (PUSCH) (e.g., a transmission resource configured via an RRC message, or a transmission resource indicated by a PDCCH of a target base station where the UE monitors the PDCCH) without transmitting a preamble. In the above case, if the configured transmission resource (PUSCH) (e.g., a transmission resource configured via an RRC message, or a transmission resource indicated by a PDCCH of a target base station where the UE monitors the PDCCH) is greater than the first threshold, or if the RRC message includes the configured value for timing adjustment (timing advance value), the UE can determine that the first condition is satisfied before starting the two-step random access, when transmitting data, or before transmitting data.

[0174] -1> When the UE in the RRC inactive mode transmits the RRCResumeRequest message, and then receives the RRCResume message (or the RRCSetup message) in response thereto, the UE can determine that the first condition is satisfied.

[0175] -1> Alternatively, until a time point n+X, when the time point n+X is reached, or when the time point n+X has passed, wherein n denotes a time point at which the recovery or activation of the cell group is indicated via an RRC message, MAC control information, or DCI information of a PDCCH (the time unit of n or X can be a time unit such as a symbol unit, a subframe unit, a millisecond (ms) unit, or a slot unit, and X can be configured in an RRC message and can be a value predefined and designated by another method),

[0176] If the first condition is satisfied, an upper layer (an upper layer entity) (e.g., an RRC layer (an RRC entity)) can perform an indication to a lower layer (a lower layer entity) (e.g., a PDCP layer (a PDCP entity), an RLC layer (an RLC entity), a MAC layer (a MAC entity), or a PHY layer (a PHY entity)) using an indicator, or the lower layer (e.g., the PDCP layer, the RLC layer, the MAC layer, or the PHY layer) can perform the indication to the upper layer (e.g., the RRC layer).

[0177] In the disclosure, a bandwidth part (BWP) can be used regardless of a distinction between uplink and downlink, and the bandwidth part can indicate each of an uplink bandwidth part and a downlink bandwidth part according to a context.

[0178] In the disclosure, a link can be used regardless of a distinction between uplink and downlink, and the link can indicate each of uplink and downlink according to a context.

[0179] In the disclosure, a cell can indicate a PCell, an SCell (e.g., an SCell configured in a master cell group (MCG)), a PSCell (e.g., a PCell of a secondary cell group (SCG)), or an SCell (e.g., an SCell configured in a secondary cell group (SCG)). In the disclosure, for an SCell or a PSCell of a UE performing carrier aggregation or dual connectivity, a dormant bandwidth part (dormant BWP) can be configured (or introduced), and thus battery consumption can be reduced by preventing the UE from performing PDCCH monitoring in the dormant bandwidth part. The UE can perform channel measurement in the dormant bandwidth part, can report (e.g., channel state information (CSI) or channel quality information (CQI) measurement or reporting) a channel measurement result to a base station, and can perform beam measurement, beam tracking, or beam operation, so that when data transmission is required, the UE can perform switching to or activation to a normal bandwidth part in order to quickly start data transmission in the normal bandwidth part. The dormant bandwidth part can neither be configured nor applied to an SPCell (a PCell of an MCG or a PCell (or PSCell) of an SCG) or an SCell for which a PUCCH has been configured, in which the SPCell needs to continuously monitor a signal, transmit or receive feedback, or check and maintain synchronization.

[0180] If the UE receives an indication about switching to or activation to a dormant bandwidth part of an SCell of a master cell group via a PCell, the UE can perform channel measurement on the dormant bandwidth part of the SCell, and can report the obtained channel measurement result via a transmission resource of a PCell of the master cell group (MCG) (e.g., via a physical uplink control channel (PUCCH) transmission resource of the PCell) or via a transmission resource of an SCell for which a PUCCH of the master cell group is configured (e.g., via a physical uplink control channel (PUCCH) transmission resource). The UE can be configured with a transmission resource (e.g., a PUCCH or a PUSCH) of a cell via an RRC message for each cell or each bandwidth part, and a channel measurement result for a specific cell or a bandwidth part thereof will be reported via the transmission resource.

[0181] If the UE receives an indication of switching to or activation to a dormant bandwidth part for an SCell of a secondary cell group via a PSCell, the UE can perform channel measurements on the dormant bandwidth part of the SCell and can report the obtained channel measurement results via a transmission resource of the PSCell of the secondary cell group (SCG) (e.g., via a physical uplink control channel (PUCCH) transmission resource of the PSCell) or via a transmission resource of an SCell for which a PUCCH of the secondary cell group is configured (e.g., via a physical uplink control channel (PUCCH) transmission resource). The UE can be configured, via an RRC message, with a transmission resource (e.g., a PUCCH or a PUSCH) of a cell for each cell or each bandwidth part, via which a channel measurement result for a specific cell or a bandwidth part thereof is to be reported.

[0182] If the UE receives an indication of switching to or activation to a dormant bandwidth part for a PSCell or an SCell of a secondary cell group via a PCell, or if the UE receives a cell group suspension (SCG suspension or cell group suspension) indication for a secondary cell group (SCG or PSCell), the UE can perform channel measurements on a bandwidth part (a bandwidth part configured via an RRC message or a last active bandwidth part) or a dormant bandwidth part of the PSCell or the SCell and can report the obtained channel measurement results via a transmission resource of a PCell of a master cell group (MCG) (e.g., via a physical uplink control channel (PUCCH) transmission resource of the PCell), via a transmission resource of an SCell for which a physical uplink control channel (PUCCH) of the master cell group is configured (e.g., via a PUCCH transmission resource), or via a transmission resource of a PSCell of a secondary cell group (SCG) (e.g., via a physical uplink control channel (PUCCH) transmission resource of the PSCell). The UE can be configured, via an RRC message, with a transmission resource (e.g., a PUCCH or a PUSCH) of a cell for each cell or each bandwidth part, via which a channel measurement result for a specific cell or a bandwidth part thereof is to be reported.

[0183] The present disclosure proposes various embodiments of operations performed based on a PDCCH-based DCI, a MAC CE, or an RRC message in order to operate the dormant bandwidth part or the cell group suspension state proposed above for an SCell of a UE (an SCell of a master cell group when carrier aggregation is configured, or an SCell of a secondary cell group when dual connectivity is configured) or a PSCell (a PCell of a secondary cell group when dual connectivity is configured).

[0184] A network or a base station can configure a UE with an SPCell (PCell and PSCell) and a plurality of SCells. When the UE communicates with one base station, the SPCell can indicate the PCell, and when the UE communicates with two base stations (a primary base station and a secondary base station), the SPCell can indicate the PCell of the primary base station or the PSCell of the secondary base station. The PCell or the PSCell indicates a primary cell used when the UE and the base station communicate in each MAC layer, and refers to a cell in which timing for synchronization is performed, random access is performed, HARQ ACK / NACK feedback is transmitted via a PUCCH transmission resource, and most control signals are exchanged. A technology in which the base station operates a plurality of SCells with the SPCell in order to increase transmission resources and increase uplink or downlink data transmission resources is referred to as a carrier aggregation technology or dual connectivity.

[0185] When the SPCell and the plurality of SCells are configured via an RRC message, a state (or mode) can be configured for the UE via an RRC message, a MAC CE, or a DCI of a PDCCH for each cell (PCell, PSCell, or SCell), each SCell, a bandwidth part of each SCell, or a cell group. The state (or mode) of the cell can be configured as one of an active mode (or active state) or a deactivated mode (or deactivated state). The cell in the active mode (or active state) can mean that, in the active cell or the activated cell in the active mode, the UE can exchange uplink or downlink data with the base station in an activated bandwidth part, an activated normal bandwidth part, or a bandwidth part other than an activated dormant bandwidth part of the cell, can perform a PDCCH to check an indication of the base station, can perform a channel measurement on a downlink of the cell (or the activated bandwidth part, the activated normal bandwidth part, or the bandwidth part other than the activated dormant bandwidth part of the cell) in the active mode or the active state, can periodically report measurement information to the base station, and can periodically transmit a pilot signal (a sounding reference signal (SRS)) to the base station so that the base station can perform an uplink channel measurement. Alternatively, the UE can activate or switch the activated bandwidth part of the cell to a dormant bandwidth part according to an indication (for example, a PDCCH, a MAC CE, or an RRC message) of the base station. If the dormant bandwidth part is activated in the activated cell, the UE can report a channel measurement, and can report a channel measurement result without PDCCH monitoring in the cell.

[0186] As another approach, if the cell in which the dormant bandwidth part is activated is an SCell, the UE can: not monitor PDCCH; not receive downlink data; perform channel measurements or measurement reporting; suspend configured periodic transmission resources (e.g., Type 1 periodic transmission resources (configured uplink grant Type 1)); clear or initialize configured periodic transmission resources (e.g., Type 2 periodic transmission resources (configured uplink grant Type 2)); not transmit sounding reference signals (SRS); not transmit uplink data; or not transmit PUCCH (e.g., scheduling request (SR) or preamble for random access). If the cell in which the dormant bandwidth part is activated or the cell group suspension is indicated is a PSCell, the UE can: not monitor PDCCH; monitor PDCCH with a very long periodicity; not receive downlink data; perform channel measurements or measurement reporting; suspend configured periodic transmission resources (e.g., Type 1 periodic transmission resources (configured uplink grant Type 1)); clear or initialize configured periodic transmission resources (e.g., Type 2 periodic transmission resources (configured uplink grant Type 2)); transmit sounding reference signals (SRS); not transmit uplink data; transmit PUCCH (e.g., scheduling request (SR) or preamble for random access); or perform random access.

[0187] If the cell in which activation is performed on a bandwidth part other than the dormant bandwidth part is an SCell, the UE can: monitor PDCCH; receive downlink data; perform channel measurements or measurement reporting; resume configured periodic transmission resources (e.g., Type 1 periodic transmission resources (configured uplink grant Type 1)); configure or activate configured periodic transmission resources (e.g., Type 2 periodic transmission resources (configured uplink grant Type 2)); transmit sounding reference signals (SRS); transmit uplink data; transmit PUCCH (e.g., scheduling request (SR) or preamble for random access); or perform random access.

[0188] If the cell in which activation is performed on a bandwidth part other than the dormant bandwidth part or the cell group recovery (SCG recovery) is indicated is a PSCell, the UE can: monitor PDCCH; receive downlink data; perform channel measurements or measurement reporting; resume configured periodic transmission resources (e.g., Type 1 periodic transmission resources (configured uplink grant Type 1)); configure or activate configured periodic transmission resources (e.g., Type 2 periodic transmission resources (configured uplink grant Type 2)); transmit sounding reference signals (SRS); transmit uplink data; transmit PUCCH (e.g., scheduling request (SR) or preamble for random access); or perform random access.

[0189] The dormant mode or the dormant state of a cell is a state in which a configured bandwidth part of the cell is inactive, a configured bandwidth part is inactive, or a configured bandwidth part does not have an active bandwidth part, such that the dormant mode or the dormant state of the cell can indicate that the UE cannot exchange data with the base station, does not perform PDCCH monitoring to check for an indication of the base station, neither performs channel measurement nor performs measurement reporting, or does not transmit a pilot signal.

[0190] Accordingly, in order to activate the cell in the dormant mode, the base station first configures the UE with frequency measurement configuration information via an RRC message, and the UE performs cell or frequency measurement based on the frequency measurement configuration information. The base station can receive a cell or frequency measurement report of the UE, and then can activate the dormant cell based on the frequency / channel measurement information. Accordingly, it takes a lot of latency for the base station to activate the carrier aggregation or the dual connectivity for the UE and to start data transmission or reception.

[0191] The present disclosure proposes a dormant bandwidth part (dormant BWP) or a dormant state of a bandwidth part for each activated cell (e.g., activated SCell or activated PSCell) in order to save battery power of the UE and to quickly start data transmission or reception. Alternatively, the present disclosure proposes to configure (or introduce) a dormant bandwidth part (dormant BWP) for each activated cell. Alternatively, the present disclosure proposes to configure (or introduce) an active state, a dormant state, a suspended state, a dormant state, or a resume state of a cell group state for each cell group when dual connectivity is configured for the UE, and proposes a method of performing an indication of a cell group resume (or SCG resume) or a cell group suspend (or SCG suspend), which indicates a state transition of the cell group, and UE operations according thereto.

[0192] In the dormant bandwidth part (dormant BWP in the activated SCell) or the bandwidth part in the dormant mode of the activated cell, or when the dormant bandwidth part is activated, the UE cannot exchange data with the base station, does not perform PDCCH monitoring to check the indication of the base station, or does not transmit a pilot signal, but according to the configuration of the base station, the UE periodically or when an event occurs, performs channel measurement and reports the measurement result for the measured frequency / cell / channel. Therefore, since the UE neither monitors the PDCCH nor transmits a pilot signal in the dormant bandwidth part (dormant BWP) of the activated cell, the UE can save battery power compared to the normal bandwidth part of the activated cell (or the bandwidth part other than the dormant bandwidth part), or when the normal bandwidth part of the activated cell (or the bandwidth part other than the dormant bandwidth part) is activated, and since the UE does not perform channel measurement reporting as when the cell is deactivated, the base station can quickly activate the normal bandwidth part of the activated cell based on the measurement report or based on the measurement report of the dormant bandwidth part of the activated cell, and can allow fast use of carrier aggregation in order to reduce transmission latency.

[0193] Therefore, in the present disclosure, the cell in the active mode or active state can mean that, in the cell in the active mode or activated cell, the UE can exchange uplink or downlink data with the base station in the activated bandwidth part of the cell, the activated normal bandwidth part, or the bandwidth part other than the activated dormant bandwidth part, can perform PDCCH monitoring to check the indication of the base station, can perform channel measurement on the downlink of the cell in the active mode or active state (or the activated bandwidth part of the cell, the activated normal bandwidth part, or the activated bandwidth part other than the dormant bandwidth part), can periodically report measurement information to the base station, and can periodically transmit a pilot signal (sounding reference signal (SRS)) to the base station so that the base station can perform uplink channel measurement. In the present disclosure, the cell in the active mode or active state can mean that, in the cell in the active mode or activated cell, the UE cannot exchange uplink or downlink data with the base station in the dormant bandwidth part of the activated cell, or does not perform PDDCH monitoring to check the indication of the base station, but can perform channel measurement on the downlink of the activated dormant bandwidth part of the cell in the active mode or active state, and can periodically report the measurement to the base station.

[0194] If the cell in which the dormant bandwidth part is activated or the cell group suspension is indicated is a PSCell, the UE can: not monitor a PDCCH; monitor a PDCCH with a very long period; not receive downlink data; perform channel measurement or measurement result reporting; suspend a configured periodic transmission resource (e.g., a type 1 periodic transmission resource (configured uplink grant type 1)); clear or initialize a configured periodic transmission resource (e.g., a type 2 periodic transmission resource (configured uplink grant type 2)); transmit a sounding reference signal (SRS); not transmit uplink data; transmit a PUCCH (e.g., a scheduling request (SR) or a preamble for random access); or perform random access.

[0195] In the disclosure, the dormant bandwidth part can indicate a state of a bandwidth part, or can be used as a name of a logical concept indicating a specific bandwidth part. Accordingly, the dormant bandwidth part can be activated, deactivated, or switched. For example, an indication of switching an activated second bandwidth part to a dormant bandwidth part in a first cell, an indication of shifting the first cell to a dormant state or a dormant mode, or an indication of activating a dormant bandwidth part of the first cell can be interpreted in the same manner.

[0196] In the disclosure, the normal bandwidth part can be indicated as a bandwidth part other than the dormant bandwidth part among the bandwidth parts configured for each cell of the UE via an RRC message. In the normal bandwidth part, the UE can exchange uplink or downlink data with the base station, can monitor a PDCCH to check an indication of the base station, can perform channel measurement on a downlink, can periodically report measurement information to the base station, and can periodically transmit a pilot signal (sounding reference signal (SRS)) to the base station to enable the base station to perform uplink channel measurement. The normal bandwidth part can indicate a first active bandwidth part, a default bandwidth part, a first active bandwidth part activated from dormancy, or an initial bandwidth part.

[0197] One dormant bandwidth part can be configured from among the bandwidth parts configured for each cell of the UE, and the dormant bandwidth part can be configured for downlink. As another method, one dormant bandwidth part can be configured for uplink or downlink among the bandwidth parts configured for each cell of the UE.

[0198] In the disclosure, the state of a cell group can be configured as activated, suspended, or deactivated. The state of a cell group can be indicated by a bitmap or an indicator of DCI of PDCCH, can be indicated via MAC control information, or can be indicated by an indicator of an RRC message. When the state of a cell group is indicated as active, the configuration information of a cell group configured or indicated via an RRC message (e.g., an RRCReconfiguration message, an RRCSetup message, or an RRCResume message) can be stored and applied to the UE, or can be restored or resumed, and the UE can: perform PDCCH monitoring in a PCell, a PSCell, or a configured SCell of the cell group according to the configuration via the RRC message; receive downlink data; perform channel measurement or measurement result reporting; resume a configured periodic transmission resource (e.g., a Type 1 periodic transmission resource (configured uplink grant Type 1)); configure or activate a configured periodic transmission resource (e.g., a Type 2 periodic transmission resource (configured uplink grant Type 2)); transmit a sounding reference signal (SRS); transmit uplink data; transmit a PUCCH (e.g., a scheduling request (SR) or a preamble for random access); or perform random access.

[0199] When the state of a cell group is indicated as suspended (suspended state) or deactivated, the configuration information of a cell group configured or indicated via an RRC message (e.g., an RRCReconfiguration message, an RRCSetup message, or an RRCResume message) can be stored in the UE, or can not be discarded, but can be suspended from being applied to the UE, and the UE can: not perform PDCCH monitoring in a PCell, a PSCell, or a configured SCell of the cell group according to the configuration via the RRC message; perform PDCCH monitoring with a very long period; not receive downlink data; perform channel measurement or measurement result reporting; suspend a configured periodic transmission resource (e.g., a Type 1 periodic transmission resource (configured uplink grant Type 1)); clear or initialize a configured periodic transmission resource (e.g., a Type 2 periodic transmission resource (configured uplink grant Type 2)); transmit a sounding reference signal (SRS); not transmit uplink data; transmit a PUCCH (e.g., a scheduling request (SR) or a preamble for random access); or perform random access.

[0200] When the state of a cell group is indicated as deactivated, or an indication of release of cell group configuration information is indicated, the UE can clear or discard the configuration information of a cell group configured or indicated via an RRC message (e.g., an RRCReconfiguration message, an RRCSetup message, or an RRCResume message).

[0201] Figure 5 is a diagram illustrating a procedure of providing a service to a UE by efficiently using a wide frequency bandwidth in a next-generation mobile communication system according to an embodiment of the disclosure.

[0202] Reference Figure 5 describes a method of providing a service to UEs having a plurality of different capabilities (or categories) and enabling a next-generation mobile communication system to save a battery by efficiently using a very wide frequency bandwidth.

[0203] One cell in which a base station provides a service can serve a very wide frequency band, as shown in 5-05. However, in order to provide a service to UEs having different capabilities, one cell in which a wide band is divided into a plurality of bandwidth parts can be managed.

[0204] First, an initially powered UE can search an entire frequency band provided by a service provider (PLMN) in units of a specific resource block (e.g., in units of 12 resource blocks (RB)). That is, the UE can start searching for a primary synchronization sequence (PSS) / secondary synchronization sequence (SSS) in the entire system bandwidth in units of resource blocks 5-10. If the UE detects PSS / SSS 5-01 or 5-02 while searching for a signal in units of resource blocks, the UE can read and interpret (decode) the signal and can identify the boundary between a subframe and a radio transmission resource frame (radio frame). Accordingly, the UE can distinguish subframes in units of 1 ms and can synchronize a downlink signal with a base station. A resource block (RB) corresponds to the size of a predetermined frequency resource and a predetermined time resource, and can be defined as a two-dimensional unit. For example, a unit of 1 ms can be defined for a time resource, and a unit of 12 subcarriers (1 carrier x 15 kHz = 180 kHz) can be defined for a frequency resource. When the UE completes synchronization, the UE can identify a master system information block (MIB) or minimum system information (MSI) to identify control resource set (CORESEST) information, and can identify initial access bandwidth parts (initial BWPs) 5-15 and 5-20. The CORESEST information refers to the location of a time / frequency transmission resource via which a control signal is transmitted from a base station, and indicates, for example, the location of a resource via which a PDCCH is transmitted. That is, the control resource set (CORESEST) information is information indicating from where a first system information (system information block 1 (SIB1)) is transmitted, and indicates a frequency / time resource via which a PDCCH is transmitted. When reading the first system information, the UE can check information about an initial bandwidth part (initial BWP). As described above, when the UE completes synchronization of a downlink signal with a base station and is able to receive a control signal, the UE can perform random access in an initial bandwidth part (initial BWP) of a cell in which the UE camps, can request an RRC connection configuration, and can receive an RRC message in order to perform the RRC connection configuration.

[0205] In the RRC connection configuration, a plurality of bandwidth parts can be configured for one cell (PCell, PSCell, SPCell, or SCell). A plurality of bandwidth parts can be configured for a downlink in one cell, and regardless of the downlink, a plurality of bandwidth parts can be separately configured for an uplink.

[0206] A plurality of bandwidth parts can be indicated and configured by a bandwidth part identifier (BWP identifier) so as to be used as an initial bandwidth part (initial BWP), a default bandwidth part (default BWP), a first active bandwidth part (first active BWP), a dormant bandwidth part (dormant BWP), or a first active bandwidth part activated from dormancy (first active BWP activated from dormancy).

[0207] The initial bandwidth part (initial BWP) can be used as a bandwidth part determined at a cell level (cell-specific), and each cell has one initial BWP, and can be used as a bandwidth part in which a UE accessing a cell for the first time can configure a connection to the cell via random access, or a UE that has configured a connection can perform synchronization. The base station can configure each of an initial downlink bandwidth part (initial downlink BWP) to be used in the downlink and an initial uplink bandwidth part (initial uplink BWP) to be used in the uplink for each cell. Configuration information for the initial bandwidth part can be broadcast in first system information (system information 1 (SIB1)) indicated by a CORESET, and can be reconfigured by the base station for a connected UE via an RRC message. The initial bandwidth part can be designated with bandwidth part identifier 0 so as to be used in each of the uplink and the downlink. That is, by designating the same bandwidth part identifier 0, all UEs accessing the same cell can use the same initial bandwidth part. This is because, when random access is performed, the base station can transmit a random access response (RAR) message via the initial bandwidth part, which enables all UEs to read the RAR message, thereby facilitating contention-based random access.

[0208] The first active bandwidth part (first active BWP) can be configured to be different for each UE (UE-specific), and can be designated and indicated by a bandwidth part identifier from among a plurality of bandwidth parts. The first active bandwidth part can be configured for each of the downlink and the uplink, and can be configured as each of a first active downlink bandwidth part (first active downlink BWP) and a first active uplink bandwidth part (first active uplink BWP) by a bandwidth part identifier. When a plurality of bandwidth parts are configured in one cell, the first active bandwidth part can be used for the purpose of indicating a bandwidth part that is initially activated and used. For example, when a PCell or a PSCell and a plurality of SCells are configured for a UE, and a plurality of bandwidth parts are configured for each of the PCell, the PSCell, or the SCell, if the PCell, the PSCell, or the SCell is activated, the UE can activate and use the first active bandwidth part (first active BWP) among the plurality of bandwidth parts configured for the PCell, the PSCell, or the SCell. That is, the first active downlink bandwidth part (first active downlink BWP) 5-25 can be activated and used for the downlink, and the first active uplink bandwidth part (first active uplink BWP) 5-30 can be activated and used for the uplink.

[0209] Operation 5-35 (in which the UE switches the current or active downlink bandwidth part of the cell in order to activate the first active downlink bandwidth part (or the bandwidth part configured or indicated via the RRC message) 5-40) or operation 5-45 (in which the UE switches the current or active uplink bandwidth part in order to activate the first active uplink bandwidth part (or the bandwidth part configured or indicated via the RRC message) 5-50) can be performed when the UE receives an indication of activating a cell or a bandwidth part that has been deactivated via the RRC message, the MAC control information, or the DCI. This can also be performed when an indication of shifting a cell or a bandwidth part to the dormant state or an indication of activating to the dormant bandwidth part is received via the RRC message, the MAC control information, or the DCI. This is because, when a cell or a bandwidth part is activated, the current or active downlink bandwidth part is switched 5-35 to activate the first active downlink bandwidth part (or the bandwidth part configured or indicated by the RRC message) 5-40, or the uplink bandwidth part is switched 5-45 to activate the first active uplink bandwidth part (or the bandwidth part configured or indicated by the RRC message) 5-50, and thus, even when a channel measurement report is performed in the dormant state, the base station can effectively use the carrier aggregation only when a frequency / channel should be measured and reported for the first active downlink / uplink bandwidth part. The default bandwidth part (default BWP) can be configured to be different for each UE (UE-specific), and can be designated and indicated by a bandwidth part identifier from among a plurality of bandwidth parts. The default bandwidth part can be configured only for the downlink. The default bandwidth part can be used as a bandwidth part to which a plurality of downlink bandwidth parts are backed off after a specific time. For example, a bandwidth part inactivity timer (BWP inactivity timer) can be configured for each cell or each bandwidth part via the RRC message, and the timer can be started or restarted when data transmission or reception occurs in an active bandwidth part other than the default bandwidth part, or the timer can be started or restarted when the activated bandwidth part is switched to another bandwidth part. When the timer expires, the UE can cause the downlink bandwidth part activated for the cell to be backed off or switched to the default bandwidth part. The switching can refer to deactivating the currently activated bandwidth part and activating the bandwidth part indicated for the switching, and the switching can be triggered by the RRC message, the MAC control information (MAC control element), or the L1 signaling (downlink control information (DCI) of the PDCCH). The switching can be triggered by indicating the bandwidth part to be switched or to be activated, and the bandwidth part can be indicated by a bandwidth part indicator (e.g., 0, 1, 2, 3, or 4).

[0210] The default bandwidth part is applied and used only for downlink because the base station can cause the UE to fall back to the default bandwidth part of each cell after a certain time to receive an indication (e.g., DCI of PDCCH) from the base station, thereby facilitating base station scheduling. For example, if the base station configures the default bandwidth part of the UE accessing one cell as the initial bandwidth part, the base station can continuously indicate scheduling only for the initial bandwidth part after a certain time. If the default bandwidth part is not configured in the RRC message, the initial bandwidth part can be considered as the default bandwidth part, and when the bandwidth part inactivity timer expires, the initial bandwidth part can be fallen back to.

[0211] As another method, in order to enhance the degree of freedom of the base station implementation, a default bandwidth part can also be defined and configured for uplink, and can be used as the default bandwidth part for downlink.

[0212] The dormant bandwidth part (dormant BWP) refers to a bandwidth part in a dormant mode or a dormant bandwidth part in an activated cell (dormant BWP in an activated SCell), or when the dormant bandwidth part is activated, the UE cannot exchange data with the base station, does not perform PDCCH monitoring to check the indication of the base station, or does not transmit a pilot signal, but according to the configuration of the base station, the UE periodically or when an event occurs, performs channel measurement and reports the measurement result for the measured frequency / cell / channel. Therefore, since the UE neither monitors the PDCCH nor transmits the pilot signal in the dormant bandwidth part (BWP) of the activated cell, the UE can save battery power compared to the normal bandwidth part of the activated cell (or the bandwidth part other than the dormant bandwidth part), or when the normal bandwidth part of the activated cell (or the bandwidth part other than the dormant bandwidth part) is activated, and since the UE does not perform channel measurement reporting as when the cell is deactivated, the base station can quickly activate the normal bandwidth part of the activated cell based on the measurement report or based on the measurement report of the dormant bandwidth part of the activated cell, and can allow quick use of carrier aggregation in order to reduce transmission latency.

[0213] For a first active bandwidth part activated by switching from a dormant state or a dormant bandwidth part (or a first active non-dormant bandwidth part, or a bandwidth part configured or indicated via an RRC message), when the UE operates a bandwidth part of one activated cell as a dormant bandwidth part, when the activated bandwidth part is a dormant bandwidth part in the activated cell, or when a bandwidth part other than the dormant bandwidth part is switched to the dormant bandwidth part in the cell, if the base station indicates the UE to switch the dormant bandwidth part as a bandwidth part of the activated cell to a normal bandwidth part (or a bandwidth part other than the dormant bandwidth part) via a DCI of a PDCCH, a MAC CE, or an RRC message, indicates the UE to switch (or change) an active bandwidth part in the dormant bandwidth part to a normal bandwidth part, or indicates the UE to switch (or change) or activate an active bandwidth part in the dormant bandwidth part to a normal bandwidth part (e.g., a first active bandwidth part activated from dormancy), the first active bandwidth part can be a bandwidth part that should be activated by switching a current or activated bandwidth part of the activated cell by the UE according to the indication, or a bandwidth part that should be activated from a dormant state configured via an RRC message.

[0214] Figure 6 FIG. 1 is a diagram illustrating a procedure in which a UE switches from an RRC idle mode to an RRC connected mode and a method of configuring a plurality of bandwidth parts (BWPs) and configuring a default bandwidth (default BWP) or a first active bandwidth (first active BWP) in a next-generation mobile communication system according to an embodiment of the disclosure.

[0215] Referring to Figure 6 , one cell in which a base station provides a service can serve a very wide frequency band. First, the UE can search for an entire frequency band provided by a service provider (PLMN) in units of a specific resource block (e.g., in units of 12 resource blocks (RBs)). That is, the UE can start searching for a primary synchronization sequence (PSS) / secondary synchronization sequence (SSS) in the entire system bandwidth in units of resource blocks. If the UE detects the PSS / SSS while searching for a signal in units of resource blocks, the UE can read and interpret (decode) the signal and can identify a boundary between a subframe and a radio transmission resource frame (radio frame). When the UE completes synchronization, the UE can read system information 6-01 of a cell in which the UE currently camps. That is, in 6-05, information of a control resource set (CORESEST) can be identified by identifying a master system information block (MIB) or minimum system information (MSI), and initial bandwidth part (initial BWP) information can be identified by reading system information. The CORESEST information refers to a location of a time / frequency transmission resource via which a control signal is transmitted from a base station, and can indicate, for example, a location of a resource via which a PDCCH is transmitted.

[0216] As described above, if the UE completes synchronization with the downlink signal of the base station and can receive the control signal, in the initial bandwidth part, the UE can perform random access in 6-10 (e.g., the UE transmits a random access preamble), can receive a random access response in 6-15, can request an RRC connection configuration in 6-20, can receive an RRC message 6-25, and can transmit a message indicating completion of RRC connection establishment to the base station in 6-30 in order to configure the RRC connection.

[0217] If the basic RRC connection configuration is completed, the base station can transmit an RRC message (UECapabilityEnquiry (6-35)) to the UE to inquire about the capability of the UE in order to identify the capability of the UE (UE capability). As another method, the base station can inquire about the capability of the UE to the MME or AMF in order to identify the capability of the UE. This is because if the UE has been connected previously, the MME or AMF can have stored the capability information of the UE. If there is no UE capability information expected by the base station, the base station can request the UE capability from the UE. When the UE reports the UE capability, the UE can report the following information to the base station as the UE capability, wherein the information includes whether the UE supports the dormant bandwidth part of the SCell of each cell group (the master cell group or the secondary cell group), whether the UE supports the first embodiment, the second embodiment, the third embodiment, or the fourth embodiment, whether the UE supports the dormant bandwidth part of the PSCell of each cell group, whether the UE supports the cell group suspension or restoration of the PSCell of each cell group, the number of supported cell groups, etc. The UE can also report the following information to the base station as the UE capability, wherein the information includes whether the configuration information of the SCell of the master cell group, the SCell of the secondary cell group, or the PSCell of the secondary cell group can be saved and restored, discarded, partially reconfigured, or activated via the RRCResume message in the RRC connection recovery.

[0218] The base station transmits an RRC message to the UE to identify the capability of the UE, and thus can identify the capability of the UE (e.g., the frequency band that the UE can read) or can determine the readable frequency band area. After identifying the capability of the UE, the UE can be configured with an appropriate bandwidth part (BWP). When the UE receives the RRC message inquiring about the UE capability in 6-40, in response to the reception of the RRC message, the UE can indicate the bandwidth range supported by the UE using an offset with respect to a reference center frequency, the bandwidth range supported by the current system bandwidth, etc., can directly indicate the start and end points of the supported frequency bandwidth, or can indicate the start and end points by using the center frequency and the bandwidth.

[0219] The bandwidth part can be configured via an RRCSetup message (or RRCConnectionSetup message) 6-25, an RRCResume message, or an RRCReconfiguration message 6-45 and 6-70 of an RRC connection configuration, and the RRC message can include configuration information for a PCell, a PSCell, or a plurality of SCells, and a plurality of bandwidth parts can be configured for each cell (PCell, PSCell, or SCell). When a plurality of bandwidth parts is configured for each cell, a plurality of bandwidth parts to be used in the downlink of each cell can be configured. In the case of an FDD system, a plurality of bandwidth parts to be used in the uplink of each cell can be configured separately from the downlink bandwidth parts. In the case of a TDD system, a plurality of bandwidth parts commonly used in the downlink and the uplink of each cell can be configured.

[0220] The information for configuring the bandwidth part of each cell (PCell, PSCell, or SCell) can include some of the following information.

[0221] - Downlink bandwidth part configuration information of a cell

[0222] ■ Initial downlink bandwidth part (initial downlink BWP) configuration information

[0223] ■ A plurality of bandwidth part configuration information, and a bandwidth part identifier (BWP ID) corresponding to each bandwidth part

[0224] ■ Initial state configuration information (e.g., active state, dormant state, or deactivated state) of a cell or a downlink bandwidth part

[0225] ■ A bandwidth part identifier indicating a first active downlink bandwidth part (first active downlink BWP)

[0226] ■ A bandwidth part identifier indicating a default bandwidth part (default BWP)

[0227] ■ Configuration information for PDCCH monitoring for each bandwidth part. For example, CORESEST information, search space resource information, PDCCH transmission resource, period, subframe number information, etc.

[0228] ■ A bandwidth part identifier indicating a dormant bandwidth part

[0229] ■ A bandwidth part identifier indicating a first active bandwidth part activated from a dormant state

[0230] ■ Bandwidth part inactivity timer configuration and timer value

[0231] - Uplink bandwidth part configuration information of a cell

[0232] ■Initial uplink bandwidth part (initial uplink BWP) configuration information

[0233] ■Multiple pieces of bandwidth part configuration information, and a bandwidth part identifier (BWP ID) corresponding to each bandwidth part

[0234] ■Initial state configuration information of a cell or an uplink bandwidth part (e.g., an active state, a dormant state, or a deactivated state)

[0235] ■A bandwidth part identifier indicating a first active uplink bandwidth part (first active uplink BWP)

[0236] - Configuration information related to a transmission resource via which a channel measurement is performed in a dormant bandwidth part or a bandwidth part other than the dormant bandwidth part, and a measurement result is reported (e.g., PUCCH transmission resource information of a PCell, a PUCCH SCell, or a PSCell).

[0237] After the RRCConnectionReconfiguration message is received in 6-45, 6-70, and 6-85, respectively, the UE can transmit an RRCConnectionReconfigurationComplete message 6-50, 6-75, and 6-90. The UE can configure or switch a BWP in 6-55 or 6-80, and the UE can configure or switch a BWP for handover in 6-95. After the UE configures or switches a BWP for handover in 6-95, the UE can perform random access in 6-100.

[0238] The configured initial bandwidth part (initial BWP), default bandwidth part (default BWP), or first active bandwidth part (first active BWP) can be used for the following purposes, and can be operated as follows according to the purposes.

[0239] An initial bandwidth part (initial BWP) can be used as a bandwidth part determined at a cell level (cell-specific), each cell has one initial BWP, and the initial BWP can be used as a bandwidth part in which a UE accessing a cell for the first time can configure a connection to the cell via random access or a UE that has configured a connection can perform synchronization. The base station can configure each of an initial downlink bandwidth part (initial downlink BWP) to be used in the downlink and an initial uplink bandwidth part (initial uplink BWP) to be used in the uplink for each cell. Configuration information for the initial bandwidth part can be broadcast in first system information (system information 1 (SIB1)) indicated by a CORESET, and can be reconfigured by the base station for a connected UE via an RRC message. The initial bandwidth part can be designated with a bandwidth part identifier 0 so as to be used in each of the uplink and the downlink. That is, by designating the same bandwidth part identifier 0, all UEs accessing the same cell can use the same initial bandwidth part. This is because, when random access is performed, the base station can transmit a random access response (RAR) message via the initial bandwidth part, which enables all UEs to read the RAR message, thereby facilitating to promote contention-based random access.

[0240] A first active bandwidth part (first active BWP) can be configured to be different for each UE (UE-specific), and can be designated and indicated by a bandwidth part identifier from among a plurality of bandwidth parts. The first active bandwidth part can be configured for each of the downlink and the uplink, and can be configured as each of a first active downlink bandwidth part (first active downlink BWP) and a first active uplink bandwidth part (first active uplink BWP) by a bandwidth part identifier. When a plurality of bandwidth parts are configured in one cell, the first active bandwidth part can be used for the purpose of indicating a bandwidth part that is initially activated and used. For example, when a PCell or a PSCell and a plurality of SCells are configured for a UE, and a plurality of bandwidth parts are configured for each of the PCell, the PSCell, or the SCell, if the PCell, the PSCell, or the SCell is activated, the UE can activate and use the first active bandwidth part (first active BWP) among the plurality of bandwidth parts configured for the PCell, the PSCell, or the SCell. That is, the first active downlink bandwidth part (first active downlink BWP) can be activated and used for the downlink, and the first active uplink bandwidth part (first active uplink BWP) can be activated and used for the uplink.

[0241] The operation of the UE switching the current or active downlink bandwidth part of a cell in order to activate the first active downlink bandwidth part (or the bandwidth part configured or indicated via the RRC message) or the operation of the UE switching the current or active uplink bandwidth part in order to activate the first active uplink bandwidth part (or the bandwidth part configured or indicated via the RRC message) can be performed when the UE receives an indication to activate the bandwidth part of the active cell or the cell that has been deactivated or dormancy, or when the UE receives an indication to switch or activate the bandwidth part that is to be deactivated or dormancy to a normal bandwidth part, where the indication is received via the RRC message, the MAC control information, or the DCI of the PDCCH. When the UE receives an indication to transfer the active cell or the active bandwidth part to a dormancy state via the RRC message, the MAC control information, or the DCI of the PDCCH, or receives an indication to switch or activate it to a dormancy bandwidth part, the UE can switch or activate the bandwidth part to a dormancy bandwidth part, or can dormancy the bandwidth part.

[0242] In the above description, putting a bandwidth part into dormancy, switching to a dormant bandwidth part, or activating to a dormant bandwidth part can refer to performing operations proposed in the disclosure in a dormant state. That is, in a dormant bandwidth part, the UE does not perform PDCCH monitoring, but can perform channel measurement on a downlink bandwidth part (or a dormant bandwidth part), and can report the channel measurement result to the base station. As another method, when an activated cell or an activated bandwidth part is activated or switched to a normal bandwidth part, the downlink bandwidth part is switched so as to be activated to a first active downlink bandwidth part, and the uplink bandwidth part is switched so as to be activated to a first active uplink bandwidth part, and thus the dormant bandwidth part can be configured as a default bandwidth part or a first active downlink or uplink bandwidth part. The default bandwidth part (default BWP) can be configured to be different for each UE (UE-specific), and can be specified and indicated by a bandwidth part identifier from among a plurality of bandwidth parts. The default bandwidth part can be configured only for downlink. The default bandwidth part can be used as a bandwidth part to which a plurality of downlink bandwidth parts are backed up after a certain time. For example, a bandwidth part inactivity timer (BWP inactivity timer) can be configured for each cell or each bandwidth part via an RRC message, and when data transmission or reception occurs in an active bandwidth part other than the default bandwidth part, the timer can start or restart, or when the activated bandwidth part is switched to another bandwidth part, the timer can start or restart. When the timer expires, the UE can cause the downlink bandwidth part activated for the cell to back up or switch to the default bandwidth part. The switching can refer to deactivating the currently activated bandwidth part and activating an indicated bandwidth part for switching, and the switching can be triggered by an RRC message, a MAC control information (MAC control element), or L1 signaling (downlink control information (DCI) of a PDCCH). The switching can be triggered by indicating a bandwidth part to be switched or to be activated, and the bandwidth part can be indicated by a bandwidth part indicator (e.g., 0, 1, 2, 3, or 4).

[0243] The default bandwidth part is applied and used only for downlink, because the base station can cause the UE to back up to the default bandwidth part of each cell after a certain time to receive an indication (e.g., DCI of a PDCCH) from the base station, thereby facilitating base station scheduling. For example, if the base station configures the default bandwidth part of the UE accessing one cell as an initial bandwidth part, the base station can continuously indicate scheduling only for the initial bandwidth part after a certain time. If the default bandwidth part is not configured in an RRC message, the initial bandwidth part can be considered as the default bandwidth part, and can back up to the initial bandwidth part when the bandwidth part inactivity timer expires.

[0244] In another method, in order to enhance the degree of freedom implemented by the base station, a default bandwidth part can also be defined and configured for the uplink, and can be used as the default bandwidth part of the downlink.

[0245] The dormant bandwidth part (dormant BWP) refers to a bandwidth part in the dormant mode or a dormant bandwidth part in the activated cell (dormant BWP in the activated SCell), or when the dormant bandwidth part is activated, the UE cannot exchange data with the base station, does not perform PDCCH monitoring to check the indication of the base station, or does not transmit a pilot signal, but according to the configuration of the base station, the UE periodically or when an event occurs, performs channel measurement and reports the measurement result for the measured frequency / cell / channel. Therefore, since the UE neither monitors the PDCCH nor transmits the pilot signal in the dormant bandwidth part (BWP) of the activated cell, the UE can save battery power compared to the normal bandwidth part of the activated cell (or the bandwidth part other than the dormant bandwidth part), or when the normal bandwidth part of the activated cell (or the bandwidth part other than the dormant bandwidth part) is activated, and since the UE does not perform channel measurement reporting as when the cell is deactivated, the base station can quickly activate the normal bandwidth part of the activated cell based on the measurement report or based on the measurement report of the dormant bandwidth part of the activated cell, and can allow fast use of carrier aggregation in order to reduce transmission latency.

[0246] For the first active bandwidth part (or the first active non-dormant bandwidth part) activated from the dormancy, when the UE operates the bandwidth part of one activated cell as the dormant bandwidth part, when the activated bandwidth part is the dormant bandwidth part in the activated cell, or when the bandwidth part other than the dormant bandwidth part is switched to the dormant bandwidth part in the cell, if the base station instructs the UE to switch the bandwidth part of the activated cell from the dormant bandwidth part to the normal bandwidth part (or the bandwidth part other than the dormant bandwidth part) via the DCI of the PDCCH, the MAC CE, or the RRC message, instructs the UE to switch (or change) the active bandwidth part in the dormant bandwidth part to the normal bandwidth part, or instructs the UE to switch (or change) or activate the active bandwidth part in the dormant bandwidth part to the normal bandwidth part (for example, the first active bandwidth part activated from the dormancy), the bandwidth part to which the UE should switch or activate the bandwidth part of the activated cell according to the instruction can be the first active bandwidth part activated from the dormancy configured via the RRC message.

[0247] In the present disclosure, switching the first bandwidth part to the second bandwidth part can be interpreted as activating the second bandwidth part, or can be interpreted as deactivating the activated first bandwidth part and activating the second bandwidth part.

[0248] In the RRCSetup message 6-25, the RRCResume message, or the RRCReconfiguration message 6-45 configured in the RRC connection, a state transition timer can be configured so that the UE can perform state transition by itself even if the UE does not receive an indication from the base station via an RRC message, a MAC control information, or a DCI of a PDCCH. For example, a cell deactivation timer (ScellDeactivationTimer) can be configured for each cell, and if the cell deactivation timer expires, the cell can be transitioned to a deactivated state. Alternatively, a downlink (or uplink) bandwidth part hibernation timer (DLBWPHibernationTimer or ULBWPHibernationTimer) can be configured for each cell or each bandwidth part of each cell, or a cell hibernation timer (ScellHibernationTimer) can be configured for each cell, and if the cell hibernation timer or the downlink (or uplink) bandwidth part hibernation timer expires, the cell or the downlink (or uplink) bandwidth part can be transitioned to a dormant state or can be switched to a dormant bandwidth part. For example, when the cell hibernation timer or the downlink (or uplink) bandwidth part hibernation timer expires, the activated cell or the downlink (or uplink) bandwidth part can be transitioned to a dormant state or can be switched to a dormant bandwidth part, and the deactivated or dormant cell or the dormant downlink (or uplink) bandwidth part cannot be transitioned to a dormant state or switched to a dormant bandwidth part. The bandwidth part hibernation timer can be started when an indication of switching or activating a bandwidth part (e.g., a bandwidth part other than a dormant bandwidth part) is received via an RRC message, a MAC CE, or a DCI of a PDCCH, or the bandwidth part hibernation timer can be suspended when an indication of switching to a dormant bandwidth part, an indication of dormancy, or an indication of activating a dormant bandwidth part is received via an RRC message, a MAC CE, or a DCI of a PDCCH. For each cell or downlink (or uplink) bandwidth part, a dormant state cell deactivation timer (dormantScellDeactivationTimer) or a dormant state deactivation timer or a downlink (or uplink) dormant bandwidth part deactivation timer (dormantDLDeactivationTimer or dormantULDeactivationTimer) can be configured in order to transition a cell or a downlink (or uplink) dormant bandwidth part in a dormant state to a deactivated state.When the dormancy state cell deactivation timer or the dormancy state deactivation timer or the downlink (or uplink) dormancy bandwidth part deactivation timer expires, only the dormant cell or downlink (or uplink) dormancy bandwidth part is transferred to the deactivated state, and the active or deactivated cell or downlink (or uplink) bandwidth part is not transferred to the deactivated state. The dormancy bandwidth part hibernation timer can be started when an indication to switch to a dormant bandwidth part, an indication of dormancy, or an indication to activate a dormant bandwidth part is received via an RRC message, a MAC CE, or a DCI of a PDCCH, or the dormancy bandwidth part hibernation timer can be suspended when an indication to deactivate or activate a bandwidth part or a cell or an indication to activate a normal bandwidth part (e.g., a bandwidth part configured via RRC other than a dormant bandwidth part) is received via an RRC message, a MAC CE, or a DCI of a PDCCH. If the cell deactivation timer (ScellDeactivationTimer) (or the downlink (or uplink) bandwidth part hibernation timer) and the cell hibernation timer (ScellHibernationTimer) (or the downlink (or uplink) dormancy bandwidth part deactivation timer) are configured together, the cell hibernation timer (ScellHibernationTimer) (or the downlink (or uplink) dormancy bandwidth part hibernation timer) is prioritized. That is, when the cell hibernation timer (ScellHibernationTimer) (or the downlink (or uplink) bandwidth part hibernation timer) is configured, even if the cell deactivation timer (ScellDeactivationTimer) (or the downlink (or uplink) dormancy bandwidth part deactivation timer) expires, the corresponding cell or downlink (or uplink) bandwidth part is not deactivated. In other words, when the cell hibernation timer (or the downlink (or uplink) bandwidth part hibernation timer) is configured, the cell or downlink (or uplink) bandwidth part is first transferred from the active state to the dormant state due to expiration of the timer, or is switched to a dormant bandwidth part, and the cell or bandwidth part transferred to the dormant state is gradually re-transferred to the deactivated state due to expiration of the dormancy state cell deactivation timer or the bandwidth part inactivity timer. Therefore, if the cell hibernation timer or the bandwidth part hibernation timer is configured, the cell deactivation timer or the dormancy bandwidth part deactivation timer does not affect the state transition of the cell or downlink (or uplink) bandwidth part, and if the cell hibernation timer or the bandwidth part hibernation timer is configured, the cell or downlink (or uplink) bandwidth part is not immediately transferred to the deactivated state even when the cell deactivation timer or the dormancy bandwidth part deactivation timer expires.

[0249] If the cell dormancy timer (or downlink (or uplink) bandwidth part dormancy timer) is not configured in the RRC message, the UE can consider that the cell dormancy timer (or downlink (or uplink) bandwidth part dormancy timer) is configured as an infinite value.

[0250] In the RRC connection-configured RRCSetup message 6-25, RRCResume message, or RRCReconfiguration message 6-45, frequency measurement configuration information (measurement configuration), frequency measurement gap information (measurement gap information), etc. can be configured, and frequency measurement object (measurement object) information can be included. In the RRC connection-configured RRCSetup message 6-25, RRCResume message, or RRCReconfiguration message 6-45, a function for reducing power consumption of the UE (power saving mode) and configuration information such as a discontinuous reception (DRX) cycle, an offset, an on duration (a time in which the UE needs to monitor a PDCCH), or time information, etc. can be configured, and in addition to the function for reducing power consumption, information on a time in which the PDCCH from the base station is monitored or detected before the on duration in the DRX cycle, short time cycle information, etc. can be configured. If the function for reducing power consumption of the UE is configured, the UE can configure a DRX cycle, and can detect a wake-up signal (WUS) in a period configured for monitoring the PDCCH of the base station before the on duration, and the base station can indicate to the UE whether to skip (or not to perform) or to perform PDCCH monitoring in the immediately following on duration via DCI of the PDCCH of the WUS. The UE always needs to monitor the PDCCH in the on duration in which the base station indicates to the UE not to perform PDCCH monitoring in the on duration in order to be able to reduce battery consumption.

[0251] When the RRC connection configuration is completed as described above, the UE can configure a plurality of bandwidth parts according to an indication configured via the RRC message. To save the battery, one or a small number of bandwidths among the plurality of configured bandwidths can be activated. For example, the base station can indicate one bandwidth part to be activated to the UE. The base station can indicate the activation of the bandwidth part via the RRC message, the MAC control information (MAC CE), or the L1 signaling (PHY layer control signal such as DCI of the PDCCH) in order to indicate the switching from the initial access bandwidth part to the new bandwidth part. As another method, new bitmap information can be defined in the DCI of the PDCCH, and can indicate whether to activate the normal bandwidth part (or the bandwidth part other than the dormant bandwidth part), whether to activate the dormant bandwidth part, or whether to deactivate the bandwidth part. As another method, the bitmap can indicate whether to activate the normal bandwidth part (e.g., the first active bandwidth part to be activated from dormancy), whether to activate the dormant bandwidth part, whether to switch to the dormant bandwidth part, or whether to perform the bandwidth part switching. Since many other new users can access the initial access bandwidth part, it can be more advantageous in terms of scheduling to assign a new bandwidth part and manage the connected users separately. This is because the initial access bandwidth part is not configured for each UE, but can be shared and commonly used for all UEs. In addition, in order to reduce the signaling overhead, the default bandwidth part (default BWP) can be dynamically indicated by the MAC control information, the L1 signaling, or the system information.

[0252] In the RRC message (RRCSetup message 6-25, RRCResume message, or RRCReconfiguration message 6-70), configuration information for the cell group can also be included. The configuration information for the cell group can include some or a plurality of information from the following information, or can indicate the state, procedure, application, or release, etc. of the configuration information for each cell group.

[0253] - a cell group identifier (e.g., cell group identifier or index) indicating the cell group

[0254] - an indicator indicating the state of the cell group (e.g., active state, suspended state, or deactivated state)

[0255] - an indicator indicating the state of the cell group (e.g., an indicator for suspending (or deactivating) the cell group (e.g., cell group (SCG) suspension indicator) or an indicator for resuming (or activating) the cell group (e.g., cell group (SCG) resume indicator))

[0256] - an indicator for triggering a procedure of a corresponding protocol layer (e.g., an SDAP layer, a PDCP layer, an RLC layer, or a MAC layer) according to an indicator (e.g., a PDCP re-establishment indicator, a PDCP data recovery indicator, an indicator for triggering a new procedure, an RLC re-establishment indicator, a MAC layer initialization indicator, or a MAC layer partial initialization indicator) indicating a state of a cell group.

[0257] - When including an indicator for suspending (or deactivating) a state of a cell group, a second DRX configuration information (e.g., a monitoring time, an active time (on duration) length, a period, an offset, etc.) can be configured, which enables PDCCH monitoring to be performed in a PSCell of the cell group with a very long period. For example, when the UE receives an indicator for suspending the cell group, the UE can perform PDCCH monitoring based on a very long period by applying the second DRX configuration information in order to save power of the UE. As another method, when the UE receives an indicator for suspending the cell group, the UE can activate or switch a downlink bandwidth part of a PSCell of the cell group to a dormant bandwidth part by applying a bandwidth part configuration information for the PSCell of the cell group, and can perform the UE operation proposed in the disclosure in a cell for which the dormant bandwidth part is activated. When the UE receives an indicator for suspending the cell group, the UE can deactivate all SCells configured in the cell group. As another method, when the UE receives an indicator for suspending the cell group, the UE can activate or switch a downlink bandwidth part to a dormant bandwidth part for SCells for which a dormant bandwidth part is configured among the SCells configured in the cell group, and can perform the UE operation proposed in the disclosure in a cell for which the dormant bandwidth part is activated, or can perform deactivation for SCells for which the dormant bandwidth part is not configured. As another method, when the UE receives an indicator for suspending the cell group via an RRC message, the UE can activate or deactivate each SCell of the cell group, put each SCell to sleep, or activate a dormant bandwidth part according to an indicator or configuration information for each SCell of the cell group included in the RRC message, or the UE can activate or deactivate each SCell of the cell group, put each SCell to sleep, or activate a dormant bandwidth part via an indicator (e.g., a bitmap) of DCI of a PDCCH, MAC control information, or an RRC message before or after receiving an indicator for suspending the cell group.

[0258] - configuration information related to a transmission resource via which a channel measurement is performed in a dormant bandwidth part or a bandwidth part other than the dormant bandwidth part, and a measurement result is reported (e.g., PCell, PUCCH SCell, or PSCell PUCCH transmission resource information)

[0259] - When including an indicator for resuming (or activating) the state of the cell group, the first DRX configuration information (e.g., monitoring time, active time (on duration) length, periodicity, offset, etc.) that enables PDCCH monitoring to be performed again in the PSCell of the cell group can be configured. Alternatively, the first DRX configuration information stored for the cell group can be restored and applied. For example, when the UE receives an indicator for resuming the cell group, the UE can perform PDCCH monitoring by applying the stored first DRX configuration information or the first DRX configuration information received via the RRC message, thereby resuming data transmission or reception. As another method, when the UE receives an indicator for resuming the cell group, by applying the bandwidth part configuration information for the PSCell of the cell group, the UE can activate or switch the downlink bandwidth part of the PSCell of the group to a bandwidth part other than the dormant bandwidth part (e.g., a bandwidth part configured via the RRC message), and the UE can perform the UE operation proposed in the disclosure in the cell for which a normal bandwidth part (a bandwidth part other than the dormant bandwidth part) is activated. Alternatively, when the UE receives an indicator for resuming the cell group, the UE can trigger random access in the PSCell of the cell group by applying the stored random access configuration information or the random access configuration information received via the RRC message, wherein the random access configuration information includes random access transmission resource information (time or frequency transmission resource), dedicated preamble information for transmitting a preamble, etc. As another method, when the UE receives an indicator for resuming the cell group, if the RRC message includes random access configuration information (random access transmission resource information (time or frequency transmission resource), dedicated preamble information for transmitting a preamble, etc.), the UE can trigger random access (e.g., contention-free random access) in the PSCell of the cell group by applying the random access configuration information, and if the RRC message for indicating the resumption or activation of the cell group does not include random access configuration information (random access transmission resource information (time or frequency transmission resource), dedicated preamble information for transmitting a preamble, etc.), the UE can trigger random access (e.g., contention-based random access) in the PSCell of the cell group, or can trigger random access (contention-based random access or 2-step random access) based on system information. If random access configuration information (random access transmission resource information (time or frequency transmission resource), dedicated preamble information for transmitting a preamble, etc.) is stored in the UE before receiving an indicator for resuming the cell group, the stored random access configuration information can be released or discarded. As another method, the UE can perform PDCCH monitoring in the indicated or configured cell group or cell, and can trigger and perform random access as indicated in the PDCCH.

[0260] - If an indicator for resuming (or activating) the state of the cell group is included, or when the UE receives an indicator for resuming the cell group, all of the SCells configured in the cell group can be activated. As another method, when the UE receives an indicator for resuming the cell group, the UE can activate or switch the downlink bandwidth part to a bandwidth part other than the dormant bandwidth part (e.g., a first active bandwidth part or a bandwidth part configured via an RRC message) for an SCell for which a dormant bandwidth part is configured among the SCells configured in the cell group, and can perform the UE operation proposed in the disclosure in a cell for which a bandwidth part other than the dormant bandwidth part is activated, or can perform activation on a cell for which no dormant bandwidth part is configured. As another method, when the UE receives an indicator for resuming the cell group via an RRC message, the UE can activate or deactivate each SCell of the cell group, put each SCell to sleep, or activate a dormant bandwidth part according to an indicator or configuration information on each SCell of the cell group included in the RRC message, or the UE can activate or deactivate each SCell of the cell group, put each SCell to sleep, or activate a dormant bandwidth part via an indicator of a PDCCH (e.g., a bitmap), MAC control information, or an RRC message before or after receiving an indicator for resuming the cell group.

[0261] - An indicator for adding a cell group configuration

[0262] - An indicator for releasing a cell group configuration

[0263] - Security configuration information (security key information, security key information for a cell group, or additional information (e.g., sk-counter)

[0264] - An indicator indicating handover, cell group addition, or cell group change (e.g., a ReconfigurationWithSync indicator or a mobilitycontrolInfo indicator)

[0265] - First channel measurement configuration information or second channel measurement configuration information for quickly activating a cell group or a cell

[0266] It is proposed that if an RRC message (e.g., RRCReconfiguration message) includes an indicator for suspending a cell group, an indicator (e.g., ReconfigurationWithSync indicator or mobilitycontrolInfo indicator) indicating handover, cell group addition, or cell group change is not included, and it is proposed that if an RRC message includes an indicator for resuming a cell group or configuration information for configuring a cell group, an indicator (e.g., ReconfigurationWithSync indicator or mobilitycontrolInfo indicator) indicating handover, cell group addition, or cell group change is included. This is because, when a cell group is resumed, connection with the cell group should be performed again, and thus synchronization should be performed, system information should be received, or random access should be performed if necessary.

[0267] Hereinafter, a dormant bandwidth part is newly proposed in a next-generation mobile communication system to which the disclosure is applicable, and in particular, UE operation in each bandwidth part when each bandwidth part is transferred or switched is proposed.

[0268] Figure 7 is a diagram illustrating a bandwidth part-specific state transition procedure or a bandwidth part switching procedure according to an embodiment of the disclosure.

[0269] Referring to Figure 7 , the bandwidth part of each cell (e.g., SCell or PSCell) of each cell group of the UE can be activated to a normal bandwidth part 7-01, can be activated to a dormant bandwidth part 7-02, or can be deactivated 7-03, and the normal bandwidth part or the dormant bandwidth part can be activated or deactivated via indication by DCI through PDCCH, MAC control information, or configuration information of an RRC message.

[0270] The state transition (activation, deactivation, or dormancy) of each bandwidth part of the cell proposed in the disclosure, activation of the normal bandwidth part, activation of the dormant bandwidth part, activation of the first active bandwidth part activated from dormancy, or deactivation of the normal bandwidth part or the dormant bandwidth part can be performed based on one of the following configuration indications.

[0271] - If the bandwidth part state of the cell is configured via an RRC message, if the bandwidth part of each cell is configured via an RRC message and a dormant bandwidth part is configured for the cell, or if the first active bandwidth part is configured as a dormant bandwidth part, the cell is activated by switching or activating to the dormant bandwidth part, and operation in the dormant bandwidth part is performed.

[0272] - If a cell activation, deactivation, or dormancy MAC CE is received,

[0273] - if a MAC CE indicating activation or deactivation of the first active bandwidth part or the dormant bandwidth part from the normal bandwidth part or dormancy is received,

[0274] - if a DCI of a PDCCH indicating activation, deactivation, or switching of the first active bandwidth part or the dormant bandwidth part from the normal bandwidth part or dormancy is received,

[0275] - if no cell dormancy timer is configured for the active state cell, and a configured cell inactivity timer expires, and

[0276] - if no bandwidth part dormancy timer is configured for the active state bandwidth part, and a configured bandwidth part inactivity timer (e.g., bwpInactivityTimer) expires, then

[0277] The state transition operation or the dormant bandwidth part operation method proposed in the present disclosure can have the following characteristics.

[0278] - For the SPCell (PCell or PSCell) (or the downlink bandwidth part or the uplink bandwidth part of the cell), the dormant bandwidth part cannot be configured, and only the normal bandwidth part is configured and always activated. Since synchronization is performed in the SPCell and a primary control signal is transmitted or received, if the bandwidth part of the SPCell is dormant or deactivated, or operates as a dormant bandwidth part, the connection with the base station can be disconnected, so that the bandwidth part of the SPCell should always remain active.

[0279] - If PUCCH is still configured for the SCell or the bandwidth part of the SCell, the dormant state or the dormant bandwidth part cannot be configured. Since there can be another cell that needs to transmit feedback (such as HARQ ACK / NACK via PUCCH), the active state or the normal bandwidth part should be activated and used.

[0280] - Due to the above characteristics, neither the cell deactivation timer (ScellDeactivationTimer) nor the bandwidth part dormancy timer is applied to the SCell or the bandwidth part of the SCell for which PUCCH is configured and the SPCell or the bandwidth part of the SPCell, and the timer can only operate for other SCells.

[0281] - Scell Hibernation Timer or BWP Hibernation Timer is prioritized over Scell Deactivation Timer or BWP Inactivity Timer. For the timer value, if one timer value is configured via an RRC message, the same value can be applied to all cells. As another method, considering the characteristics of each SCell or each BWP, the base station can configure different timer values for each SCell or each BWP.

[0282] - Unless it is indicated via an RRC message whether a cell or a bandwidth part is active or hibernated, by default, a cell or a bandwidth part initially operates in a deactivated state.

[0283] In the disclosure, uplink can indicate an uplink bandwidth part, and downlink can indicate a downlink bandwidth part. This is because only one active or hibernated bandwidth part is operable for each uplink or downlink.

[0284] Hereinafter, a method capable of operating state transition or switching in a bandwidth part level is specifically proposed in order to be able to quickly activate carrier aggregation or dual connectivity and save UE battery power.

[0285] In the disclosure, a bandwidth part can be configured for each cell via a reference Figure 6 The described RRCSetup message, RRCReconfiguration message, or RRCResume message configures a bandwidth part for each cell as described below. The RRC message can include configuration information for a PCell, a PSCell, or a plurality of SCells, and a plurality of bandwidth parts can be configured for each cell (PCell, PSCell, or SCell). When a plurality of bandwidth parts is configured for each cell via an RRC message, a plurality of bandwidth parts to be used in the downlink of each cell can be configured. In the case of an FDD system, a plurality of bandwidth parts to be used in the uplink of each cell can be separately configured from the downlink bandwidth parts. In the case of a TDD system, a plurality of bandwidth parts commonly used in the downlink and the uplink of each cell can be configured.

[0286] In the first method of the information configuration method for configuring a bandwidth part for each cell (PCell, PSCell, or SCell), one or more of the following information is included, and a new indicator is introduced to the bandwidth part in order to indicate whether each bandwidth part is a normal bandwidth part (e.g., a bandwidth part that can be configured or can operate in an active state or a deactivated state) or a dormant bandwidth part (e.g., a bandwidth part that can be configured or can operate in a dormant state). For example, a bandwidth part identifier can be used to indicate whether a bandwidth part is a dormant bandwidth part.

[0287] - Downlink bandwidth part configuration information for each cell

[0288] ■ Initial downlink bandwidth part (initial downlink BWP) configuration information

[0289] ■ Multiple pieces of bandwidth part configuration information, and a bandwidth part identifier (BWP ID) corresponding to each bandwidth part

[0290] ■ Downlink initial state configuration information for a cell (e.g., an active state, a dormant state, or a deactivated state)

[0291] ■ Bandwidth part identifier indicating a first active downlink bandwidth part (first active downlink BWP)

[0292] ■ Bandwidth part identifier indicating a default bandwidth part (default BWP)

[0293] ■ Bandwidth part identifier indicating a dormant bandwidth part, or 1-bit indicator for each bandwidth part indicating a dormant bandwidth part in the bandwidth part configuration information

[0294] ■ If the first active downlink bandwidth part is configured as a dormant bandwidth part, the first active uplink bandwidth part can also need to be configured as a dormant bandwidth part.

[0295] ■ Bandwidth part inactivity timer configuration and timer value

[0296] ■ First bandwidth part identifier activated from a dormant bandwidth part

[0297] - Uplink bandwidth part configuration information for each cell

[0298] ■ Initial uplink bandwidth part (initial uplink BWP) configuration information

[0299] ■ Multiple pieces of bandwidth part configuration information, and a bandwidth part identifier (BWP ID) corresponding to each bandwidth part

[0300] ■ Uplink initial state configuration information for a cell (e.g., an active state, a dormant state, or a deactivated state)

[0301] ■a bandwidth part identifier indicating the first active uplink bandwidth part

[0302] ■a bandwidth part identifier indicating the dormant bandwidth part, or a 1-bit indicator for each bandwidth part indicating the dormant bandwidth part in the bandwidth part configuration information

[0303] ■If the first active downlink bandwidth part is configured as the dormant bandwidth part, the first active uplink bandwidth part can also need to be configured as the dormant bandwidth part.

[0304] ■a first bandwidth part identifier activated from the dormant bandwidth part

[0305] ■SRS-related configuration information can be configured in the following methods.

[0306] ■a first embodiment to configure SRS

[0307] ◆ first SRS configuration information (SRS configuration information for a bandwidth part of a normal bandwidth part, a bandwidth part other than a dormant bandwidth part, a PSCell (or SCell) of a cell group that is not suspended, a PSCell (or SCell) of a cell group that is resumed or activated, or a bandwidth part of the PSCell (or SCell))

[0308] ◆ second SRS configuration information (SRS configuration information for a bandwidth part of a dormant bandwidth part, a PSCell (or SCell) of a cell group that is suspended or deactivated, a PSCell (or SCell) of a cell group that is not resumed, or a bandwidth part thereof)

[0309] ◆ The first SRS configuration information and the second SRS configuration information can be distinguished based on an indicator indicating whether the SRS configuration information is for a dormant bandwidth part or a PSCell (or SCell) of a cell group that is suspended or deactivated. For example, the first SRS configuration information and the second SRS configuration information can be distinguished according to an indicator value, or can be distinguished based on whether an indicator value is configured or whether an indicator value exists. As another method, the first SRS configuration information and the second SRS configuration information can be distinguished by defining the name of the first SRS configuration information and the name of the second SRS configuration information differently.

[0310] ◆ In the first embodiment, if a dormant bandwidth part is configured for a serving cell (PSCell or SCell) (e.g., a dormant bandwidth part identifier in downlink bandwidth part configuration information), or if a cell group suspension is indicated (or supported or configured), the second SRS configuration information is always configured. Alternatively, if a dormant bandwidth part is configured for a serving cell (PSCell or SCell) (e.g., a dormant bandwidth part identifier in downlink bandwidth part configuration information), or if a cell group suspension is indicated (or supported or configured), an indicator indicating whether the SRS configuration information is the first SRS configuration information or the second SRS configuration information is configured. For example, if a dormant bandwidth part identifier is configured in downlink bandwidth part configuration information, or a cell group suspension is indicated (or supported or configured), the second SRS configuration information should be configured in each uplink bandwidth part configuration information. For example, if a dormant bandwidth part identifier is configured in downlink bandwidth part configuration information, or a cell group suspension is indicated (or supported or configured), the second SRS configuration information should be configured in uplink bandwidth part configuration information for an uplink bandwidth part having the same bandwidth part identifier as an uplink dormant bandwidth part or a downlink dormant bandwidth part. As another method, in the case of TDD or unpaired spectrum, if a dormant bandwidth part identifier is configured in downlink bandwidth part configuration information, the second SRS configuration information should be configured in uplink bandwidth part configuration information for an uplink bandwidth part having the same bandwidth part identifier as an uplink dormant bandwidth part or a downlink dormant bandwidth part.

[0311] ◆ For example, in the first embodiment, when the UE switches or activates the downlink bandwidth part of the activated cell to a bandwidth part other than the dormant bandwidth part (or normal bandwidth part), if the cell group is not indicated to be suspended, if the cell group is active, or if the cell group is indicated to be resumed, the UE can apply the first SRS configuration information in the uplink bandwidth part of the activated cell (SCell or PSCell), and can perform SRS transmission based on the SRS transmission resource, period, or offset corresponding to the first SRS configuration information. However, if the downlink bandwidth part of the activated cell is switched or activated to the dormant bandwidth part, if the cell group is indicated to be suspended, or if the cell group is not active (or deactivated or suspended), the UE can apply the second SRS configuration information in the uplink bandwidth part of the cell (PSCell or SCell) of the suspended or deactivated cell group, and can perform SRS transmission based on the SRS transmission resource, period, or offset corresponding to the second SRS configuration information. For example, by configuring the SRS transmission resource in the second SRS configuration information for the dormant bandwidth part to be much less than the SRS transmission resource configured in the first SRS configuration information for the normal bandwidth part, or by configuring the SRS transmission resource period in the second SRS configuration information to be much longer than the SRS transmission resource period configured in the first SRS configuration information, the power saving effect in the UE can be improved in the dormant bandwidth part or the suspended cell group. For example, in the second SRS configuration information, the SRS transmission period can be configured to be 100 ms or more. As another method, when the downlink bandwidth part is activated to the dormant bandwidth part, when the cell group is indicated to be suspended, or when the cell group is not active (or deactivated or suspended), if the second SRS configuration information is not configured, the UE can apply the first SRS configuration information to the uplink bandwidth part, and can perform SRS transmission based on the SRS transmission resource, period, or offset corresponding to the first SRS configuration information. As another method, when the downlink bandwidth part is activated to the dormant bandwidth part, when the cell group is indicated to be suspended, or when the cell group is not active (or deactivated or suspended), if the second SRS configuration information is not configured, the UE can not perform SRS transmission.

[0312] ■Second embodiment to configure SRS

[0313] ◆ In the second embodiment, the first SRS configuration information and the second SRS configuration information can be included in one SRS configuration information, and can be separately configured as SRS configuration information (e.g., SRS transmission resource, periodicity, or offset) for a normal bandwidth part, a bandwidth part other than a dormant bandwidth part, a PSCell (or SCell) of a cell group that is not suspended, a PSCell (or SCell) of a cell group that is resumed or activated, or a bandwidth part of the PSCell (or SCell), and SRS configuration information (e.g., SRS transmission resource, periodicity, or offset) for a dormant bandwidth part, a PSCell (or SCell) of a cell group that is suspended (or deactivated), a PSCell (or SCell) of a cell group that is not resumed, or a bandwidth part of the PSCell (or SCell).

[0314] ◆ The first SRS configuration information (SRS configuration information (e.g., SRS transmission resource, periodicity, or offset, or an indicator indicating whether the SRS configuration information is for a dormant bandwidth part) for a normal bandwidth part, a bandwidth part other than a dormant bandwidth part, a PSCell (or SCell) of a cell group that is not suspended, a PSCell (or SCell) of a cell group that is resumed or activated, or a bandwidth part of the PSCell (or SCell))

[0315] ◆ The second SRS configuration information (SRS configuration information (e.g., SRS transmission resource, periodicity, or offset, or an indicator indicating whether the SRS configuration information is for a dormant bandwidth part) for a dormant bandwidth part, a PSCell (or SCell) of a cell group that is suspended (or deactivated), a PSCell (or SCell) of a cell group that is not resumed, or a bandwidth part of the PSCell (or SCell))

[0316] ◆ In a second embodiment, the second SRS configuration information is always configured if a dormant bandwidth part is configured for the serving cell (cell) (e.g., a dormant bandwidth part identifier in the downlink bandwidth part configuration information), or if a cell group suspension is indicated (or supported or configured). Alternatively, an indicator indicating whether the SRS configuration information is the first SRS configuration information or the second SRS configuration information is configured if a dormant bandwidth part is configured for the serving cell (cell) (e.g., a dormant bandwidth part identifier in the downlink bandwidth part configuration information), or if a cell group suspension is indicated (or supported or configured). For example, if a dormant bandwidth part identifier is configured in the downlink bandwidth part configuration information, the second SRS configuration information should be configured in each uplink bandwidth part configuration information. For example, if a dormant bandwidth part identifier is configured in the downlink bandwidth part configuration information, or if a cell group suspension is indicated (or supported or configured), the second SRS configuration information should be configured in the uplink bandwidth part configuration information for the uplink bandwidth part having the same bandwidth part identifier as the uplink dormant bandwidth part or the downlink dormant bandwidth part. As another method, in the case of TDD or unpaired spectrum, if a dormant bandwidth part identifier is configured in the downlink bandwidth part configuration information, or if a cell group suspension is indicated (or supported or configured), the second SRS configuration information should be configured in the uplink bandwidth part configuration information for the uplink bandwidth part having the same bandwidth part identifier as the uplink dormant bandwidth part or the downlink dormant bandwidth part.

[0317] ◆ For example, in the second embodiment, when the UE switches or activates the downlink bandwidth part of the activated cell to a bandwidth part other than the dormant bandwidth part (or a normal bandwidth part), if the cell group is not indicated to be suspended, if the cell group is active, or if the cell group is indicated to be resumed, the UE can apply the first SRS configuration information in the uplink bandwidth part of the activated cell, and can perform SRS transmission based on the SRS transmission resource, period, or offset corresponding to the first SRS configuration information. However, if the downlink bandwidth part of the activated cell is switched or activated to the dormant bandwidth part, if the cell group is indicated to be suspended, or if the cell group is not active (or deactivated or suspended), the UE can apply the second SRS configuration information in the uplink bandwidth part of the activated cell, and can perform SRS transmission based on the SRS transmission resource, period, or offset corresponding to the second SRS configuration information. For example, by configuring the SRS transmission resource in the second SRS configuration information to be much less than the SRS transmission resource configured in the first SRS configuration information, or by configuring the SRS transmission resource period in the second SRS configuration information to be much longer than the SRS transmission resource period configured in the first SRS configuration information, the power saving effect in the UE can be improved in the dormant bandwidth part. For example, in the second SRS configuration information, the SRS transmission period can be configured to be 100 ms or more. As another method, when the downlink bandwidth part is activated to the dormant bandwidth part, when the cell group is indicated to be suspended, or when the cell group is not active (or deactivated or suspended), if the second SRS configuration information is not configured, the UE can apply the first SRS configuration information to the uplink bandwidth part, and can perform SRS transmission based on the SRS transmission resource, period, or offset corresponding to the first SRS configuration information. As another method, when the downlink bandwidth part is activated to the dormant bandwidth part, when the cell group is indicated to be suspended, or when the cell group is not active (or deactivated or suspended), if the second SRS configuration information is not configured, the UE can not perform SRS transmission.

[0318] ■Third embodiment to configure SRS

[0319] ◆ In the third embodiment, the second SRS configuration information (i.e., SRS configuration information for indicating or configuring dormancy bandwidth part or cell group suspension (e.g., SRS transmission resource, periodicity or offset)) can be configured only for the bandwidth part configured as uplink dormancy bandwidth part (bandwidth part indicated by dormancy bandwidth part identifier) in uplink bandwidth part configuration information. Alternatively, the first SRS configuration information (i.e., SRS configuration information for normal bandwidth part or bandwidth part other than dormancy bandwidth part (e.g., SRS transmission resource, periodicity or offset)) can be configured only for the bandwidth part configured as bandwidth part other than uplink dormancy bandwidth part (bandwidth part not indicated by dormancy bandwidth part identifier) in uplink bandwidth part configuration information. As another approach, in case of TDD or unpaired spectrum, if dormancy bandwidth part identifier is configured in downlink bandwidth part configuration information, the second SRS configuration information should be configured in uplink bandwidth part configuration information for uplink bandwidth part with same bandwidth part as uplink dormancy bandwidth part (bandwidth part indicated by dormancy bandwidth part identifier) or downlink dormancy bandwidth part.

[0320] ◆ For example, in the third embodiment, when the downlink bandwidth part of the activated cell is switched or activated to a bandwidth part other than the dormant bandwidth part (or a normal bandwidth part), the UE can apply the first SRS configuration information in the uplink bandwidth part of the activated cell, and can perform SRS transmission based on the SRS transmission resource, period, or offset corresponding to the first SRS configuration information. However, if the downlink bandwidth part of the activated cell is switched or activated to the dormant bandwidth part, the UE can apply the second SRS configuration information in the uplink bandwidth part of the activated cell, and can perform SRS transmission based on the SRS transmission resource, period, or offset corresponding to the second SRS configuration information. For example, by configuring the SRS transmission resource configured in the second SRS configuration information for the dormant bandwidth part to be much less than the SRS transmission resource configured in the first SRS configuration information for the normal bandwidth part, or by configuring the SRS transmission resource period configured in the second SRS configuration information for the dormant bandwidth part to be much longer than the SRS transmission resource period configured in the first SRS configuration information for the normal bandwidth part, the power saving effect in the UE can be improved in the dormant bandwidth part. For example, in the second SRS configuration information, the SRS transmission period can be configured to be 100 ms or more. As another method, when the downlink bandwidth part is activated to the dormant bandwidth part, if the second SRS configuration information is not configured, the UE can apply the first SRS configuration information to the uplink bandwidth part, and can perform SRS transmission based on the SRS transmission resource, period, or offset corresponding to the first SRS configuration information. Alternatively, when the downlink bandwidth part is activated to the dormant bandwidth part, if the second SRS configuration information is not configured, the UE can not perform SRS transmission.

[0321] As another method of the information configuration method for configuring a bandwidth part for each cell (PCell, PSCell, or SCell), in the second method, a distinction can be made so that configuration information (e.g., search space, PDCCH transmission resource, period, etc.) required for reading a PDCCH is not configured for a bandwidth part corresponding to a dormant bandwidth part (alternatively, a very long period can be configured together with other configuration information), and the configuration information (e.g., search space, PDCCH transmission resource, period, etc.) required for reading a PDCCH can be configured for a normal bandwidth part. This is because the dormant bandwidth part is a bandwidth part for reducing battery consumption of a UE by preventing PDCCH reading, performing channel measurement, and reporting a channel measurement result via a PCell to enable fast activation of a cell or a bandwidth part, thereby quickly allocating an uplink or downlink transmission resource. Accordingly, in the disclosure, the dormant bandwidth part can indicate a bandwidth part for which configuration information (e.g., search space, PDCCH transmission resource, period, etc.) for PDCCH monitoring is not configured, or can be indicated by a dormant bandwidth part identifier, or a bandwidth part for which configuration information for PDCCH monitoring is configured but PDCCH monitoring is configured to be performed with a very long period. As another method, in the disclosure, the dormant bandwidth part can indicate a bandwidth part in which: a PDCCH transmission resource, a period, etc., in the configuration information for PDCCH monitoring are not configured so as to prevent PDCCH monitoring from being performed in a cell for which the dormant bandwidth part is configured; but search space information or cross-carrier scheduling configuration information is configured, and switching or indication for the dormant bandwidth part can thus be received in another cell via cross-carrier scheduling, in which only PDCCH configuration information (PDCCH-config) is configured (e.g., only search space information is configured) for the dormant bandwidth part (or this can be referred to as a first bandwidth part) since data transmission or reception is not possible in the dormant bandwidth part. On the other hand, in a normal bandwidth part other than the dormant bandwidth part (or this can be referred to as a second bandwidth part), PDCCH monitoring needs to be performed, and data transmission or reception should also be possible, so that PDCCH configuration information (e.g., CORESEST configuration information, search space configuration information, or PDCCH transmission resource, period, etc.), PDSCH configuration information, PUSCH configuration information, random access-related configuration information, etc. can be further configured.

[0322] Therefore, although the uplink or downlink normal bandwidth part should be configured for each cell as described above, the dormant bandwidth part can or can not be configured for each cell, and the configuration can be left to the base station implementation depending on the purpose. Depending on the base station implementation, the first active bandwidth part, the default bandwidth part, or the initial bandwidth part can be configured as the dormant bandwidth part.

[0323] In the dormant bandwidth part, the UE cannot exchange data with the base station, does not perform PDCCH monitoring to check the indication of the base station, and does not transmit a pilot signal, but according to the configuration of the base station, the UE periodically or when an event occurs, performs channel measurement and reports the measurement result for the measured frequency / cell / channel. Therefore, the UE does not perform PDCCH monitoring nor transmit a pilot signal in the dormant bandwidth part, so battery consumption can be reduced compared to the active mode, and since the UE does not perform channel measurement reporting as in the deactivated mode, the base station can use carrier aggregation by quickly activating the cell for which the dormant bandwidth part is configured based on the measurement report in the dormant bandwidth part. In the present disclosure, the dormant bandwidth part is configured in the downlink bandwidth part configuration information, and is used only for the downlink bandwidth part.

[0324] In the present disclosure, when the dormant bandwidth part is activated, the UE operation for the dormant bandwidth part or the UE operation in the activated SCell or PSCell is as follows.

[0325] - If the UE receives an indication of the operation of the dormant bandwidth part via a serving cell (PCell, PSCell, or SCell) from the PCell or SPCell, if an indication to put the serving cell (e.g., SCell) or the bandwidth part (e.g., downlink bandwidth part) of the serving cell (e.g., SCell) to sleep or an indication to activate the dormant bandwidth part is received via DCI (L1 control signal) of PDCCH, MAC CE, or RRC message, if an indication to switch the bandwidth part (e.g., downlink bandwidth part) to the dormant bandwidth part is received via DCI (L1 control signal) of PDCCH, MAC CE, or RRC message (if the indication is received via the L1 control signal of PDCCH, it can be received on the PDCCH of the serving cell by self-scheduling or can be received on the PDCCH of the cell in the PCell by cross-carrier scheduling), if the bandwidth part dormancy timer is configured and expires, if the activated bandwidth part of the activated cell is the dormant bandwidth part, or if the activated bandwidth part of the activated cell is not the normal bandwidth part, one or more of the following operations can be performed.

[0326] ■Switching the uplink bandwidth part or downlink bandwidth part to the bandwidth part configured via RRC (e.g., dormant bandwidth part) and activating the bandwidth part or putting it to sleep.

[0327] ■Suspending the cell deactivation timer configured for the cell or running in the cell.

[0328] ■Suspending the bandwidth part dormancy timer configured for the bandwidth part of the cell.

[0329] ■Starting or restarting the dormant bandwidth part inactivity timer in the bandwidth part of the cell.

[0330] ■Suspending the bandwidth part inactivity timer configured for the bandwidth part of the cell. This is to prevent unnecessary bandwidth part switching in the cell.

[0331] ■The periodic downlink transmission resources (DL SPS or configured downlink assignment) or periodic uplink transmission resources (UL SPS or configured uplink grant Type 2) configured for the bandwidth part of the cell can be cleared. The clearing of the transmission resources indicates the UE to store the configuration information (such as periodic information configured via RRC message) but remove and no longer use the information about the periodic transmission resources indicated or activated via L1 signaling (e.g., DCI). The above proposed method (i.e., clearing the configured periodic downlink transmission resources (DL SPS or configured downlink assignment) or configured periodic uplink transmission resources (UL SPS or configured uplink grant)) can be performed only when the bandwidth part is moved from active state to dormant state. This is because, when the bandwidth part is moved from deactivated state to dormant state, there is no information about the periodic transmission resources indicated or activated by L1 signaling. Alternatively, only when the periodic downlink transmission resources or periodic uplink transmission resources are configured or configured to be used, the periodic transmission resources can be cleared.

[0332] ■The periodic uplink transmission resources (configured uplink grant Type 1 configured via RRC) configured for the bandwidth part of the cell can be suspended. The suspension of the transmission resources indicates the UE to store but no longer use the transmission resource configuration information configured via RRC message. The above proposed method (i.e., suspending the configured periodic uplink transmission resources (configured uplink grant Type 1)) can be performed only when the bandwidth part is moved from active state to dormant state. This is because, when the bandwidth part is moved from deactivated state to dormant state, the periodic transmission resources are not used. Alternatively, only when the periodic downlink transmission resources or periodic uplink transmission resources are configured or configured to be used, the periodic transmission resources can be cleared.

[0333] ■ Empty all HARQ buffers configured for uplink or downlink bandwidth part.

[0334] ■ The UE does not perform SRS transmission for the uplink bandwidth part of the cell.

[0335] ■ As another method, when first SRS configuration information (SRS configuration information (e.g., SRS transmission resource, periodicity, or offset) for a normal bandwidth part (a bandwidth part other than a dormant bandwidth part)) or second SRS configuration information (SRS configuration information (e.g., SRS transmission resource, periodicity, or offset) for a dormant bandwidth part) is configured in uplink bandwidth part configuration information, the UE can facilitate scheduling or power control of the network, or can perform SRS transmission in order to be able to quickly reactivate the uplink bandwidth part of the UE. For example, when the UE switches or activates the downlink bandwidth part of the activated cell to a bandwidth part other than a dormant bandwidth part (or a normal bandwidth part) (when the activated bandwidth part is not a dormant bandwidth part), the UE can apply the first SRS configuration information in the uplink bandwidth part of the activated cell, and can perform SRS transmission based on the SRS transmission resource, periodicity, or offset corresponding to the first SRS configuration information. However, if the downlink bandwidth part of the activated cell is switched or activated to a dormant bandwidth part (when the activated bandwidth part is a dormant bandwidth part), the UE can apply the second SRS configuration information in the uplink bandwidth part of the activated cell, and can perform SRS transmission based on the SRS transmission resource, periodicity, or offset corresponding to the second SRS configuration information. For example, by configuring the SRS transmission resource configured in the second SRS configuration information for a dormant bandwidth part to be much less than the SRS transmission resource configured in the first SRS configuration information for a normal bandwidth part, or by configuring the SRS transmission resource periodicity configured in the second SRS configuration information for a dormant bandwidth part to be much longer than the SRS transmission resource periodicity configured in the first SRS configuration information for a normal bandwidth part, power saving effects in the UE can be improved in a dormant bandwidth part. For example, in the second SRS configuration information, the SRS transmission periodicity can be configured to be 100 ms or more. As another method, when the downlink bandwidth part is activated to a dormant bandwidth part, if the second SRS configuration information is not configured, the UE can apply the first SRS configuration information to the uplink bandwidth part, and can perform SRS transmission based on the SRS transmission resource, periodicity, or offset corresponding to the first SRS configuration information. Alternatively, if the downlink bandwidth part is activated to a dormant bandwidth part, if the second SRS configuration information is not configured, the UE can not perform SRS transmission.

[0336] ■ As another method, if the downlink bandwidth part of the activated cell is switched or activated to a downlink dormant bandwidth part (when the activated bandwidth part is a dormant bandwidth part), the UE can switch or activate the uplink bandwidth part to an uplink dormant bandwidth part. For the uplink dormant bandwidth part, the dormant bandwidth part can be indicated by a bandwidth part identifier in the uplink bandwidth part configuration information configured via the RRC message. (For example, this can apply to the case of FDD, unpaired spectrum, or TDD). As another method, the same bandwidth part identifier as the downlink dormant bandwidth part can be the same uplink bandwidth part identifier indicating the dormant bandwidth part (for example, this can apply in the case of unpaired spectrum or TDD). The UE can apply the second SRS configuration information configured for the uplink dormant bandwidth part, and can perform SRS transmission based on the SRS transmission resource, period, or offset corresponding to the second SRS configuration information.

[0337] ■ As another method, the current uplink bandwidth part or the last activated uplink bandwidth part can be activated as is.

[0338] ■ In the bandwidth part of the cell, the UE performs channel measurement (CSI, CQI, PMI, RI, PTI, CRI, etc.) on the downlink according to the configuration of the base station, and performs measurement reporting. For example, the UE can periodically perform channel or frequency measurement reporting.

[0339] ■ Uplink data is not transmitted on the UL-SCH in the bandwidth part of the cell.

[0340] ■ Random access is not performed on the bandwidth part of the cell.

[0341] ■ The UE does not perform PDCCH monitoring in the bandwidth part of the cell.

[0342] ■ The UE does not perform PDCCH monitoring on the bandwidth part of the cell. However, in the case of cross scheduling, for a cell (e.g., SCell) in a cell (e.g., PCell) to be scheduled, an indication can be received through PDCCH monitoring.

[0343] ■ PUCCH or SPUCCH transmission is not performed in the bandwidth part of the cell.

[0344] ■ The dormant downlink bandwidth part can be dormant, channel measurement and reporting can be performed, and the uplink bandwidth part of the cell can be deactivated and not used. This is because, in the dormant cell, only the downlink bandwidth part is subjected to channel measurement, and the measurement result is reported via the uplink bandwidth part of the SPCell (PCell or PSCell) or SCell having PUCCH.

[0345] For downlink, if switching or activation to dormant bandwidth part is indicated, or if bandwidth part is indicated as dormant, random access can be performed without clearing. This is because, in a cell, when random access is performed, a preamble is transmitted via uplink, and a random access response is received via downlink of a PCell. Therefore, even if the downlink bandwidth part becomes dormant or is switched to a dormant bandwidth part, no problem occurs.

[0346] In the present disclosure, when a normal bandwidth part (active BWP) of an activated cell is activated, or when a bandwidth part other than a dormant bandwidth part is activated, the UE operates as follows.

[0347] - If an indication of activating a normal bandwidth part (e.g., downlink bandwidth part) of a current cell (PCell, PSCell, or SCell) or a normal bandwidth part other than a dormant bandwidth part or an indication of a cell is received via DCI (L1 control signal) of PDCCH, MAC CE, or RRC message, if an indication of switching a bandwidth part (e.g., downlink bandwidth part) to an active bandwidth part (or a bandwidth part other than a dormant bandwidth part) is received via DCI (L1 control signal) of PDCCH, MAC CE, or RRC message, if the activated bandwidth part of the currently activated cell is a normal bandwidth part, or if the activated bandwidth part of the currently activated cell is not a dormant bandwidth part (if the indication is received via L1 control signal of PDCCH, the indication can be received on PDCCH of the current cell by self-scheduling, or can be received on PDCCH of the cell in PCell by cross-carrier scheduling), one or more of the following operations can be performed.

[0348] ■ The UE performs switching and activation on the uplink or downlink bandwidth part indicated above. Alternatively, the UE switches the uplink or downlink bandwidth part to a designated bandwidth part (e.g., uplink or downlink first active bandwidth part), and activates the bandwidth part.

[0349] ■ The UE transmits a sounding reference signal (SRS) via the activated bandwidth part to allow the base station to perform uplink channel measurement. For example, the transmission can be performed periodically.

[0350] ■As another method, when the first SRS configuration information (SRS configuration information (e.g., SRS transmission resource, periodicity, or offset) for a normal bandwidth part (a bandwidth part other than a dormant bandwidth part)) or the second SRS configuration information (SRS configuration information (e.g., SRS transmission resource, periodicity, or offset) for a dormant bandwidth part) is configured in the uplink bandwidth part configuration information, the UE can facilitate scheduling or power control of the network, or can perform SRS transmission in order to be able to quickly reactivate the uplink bandwidth part of the UE. For example, when the UE switches or activates the downlink bandwidth part of the activated cell to a bandwidth part other than a dormant bandwidth part (or a normal bandwidth part) (when the first active bandwidth part is not a dormant bandwidth part), the UE can apply the first SRS configuration information in the uplink bandwidth part of the activated cell, and can perform SRS transmission based on the SRS transmission resource, periodicity, or offset corresponding to the first SRS configuration information. However, if the downlink bandwidth part of the activated cell is switched or activated to a dormant bandwidth part (when the first active bandwidth part is a dormant bandwidth part), the UE can apply the second SRS configuration information in the uplink bandwidth part of the activated cell, and can perform SRS transmission based on the SRS transmission resource, periodicity, or offset corresponding to the second SRS configuration information. For example, by configuring the SRS transmission resource configured in the second SRS configuration information for a dormant bandwidth part to be much less than the SRS transmission resource configured in the first SRS configuration information for a normal bandwidth part, or by configuring the SRS transmission resource periodicity configured in the second SRS configuration information for a dormant bandwidth part to be much longer than the SRS transmission resource periodicity configured in the first SRS configuration information for a normal bandwidth part, the power saving effect in the UE can be improved in a dormant bandwidth part. For example, in the second SRS configuration information, the SRS transmission periodicity can be configured to be 100 ms or more. As another method, when the downlink bandwidth part is activated to a dormant bandwidth part, if the second SRS configuration information is not configured, the UE can apply the first SRS configuration information to the uplink bandwidth part, and can perform SRS transmission based on the SRS transmission resource, periodicity, or offset corresponding to the first SRS configuration information. Alternatively, if the downlink bandwidth part is activated to a dormant bandwidth part, if the second SRS configuration information is not configured, the UE can not perform SRS transmission.

[0351] ■ As another approach, if the downlink bandwidth part of the activated cell is switched or activated to a bandwidth part other than the downlink dormant bandwidth part or a normal bandwidth part (when the first active bandwidth part is not the dormant bandwidth part), the UE can switch or activate the uplink bandwidth part to the first bandwidth part activated from the dormancy via RRC configuration. For the first bandwidth part activated from the uplink dormancy, the first bandwidth part activated from the dormancy can be indicated by the bandwidth part identifier in the uplink bandwidth part configuration information configured via the RRC message (e.g., in the case of FDD, unpaired spectrum, or TDD), and alternatively, the same bandwidth part identifier as the downlink dormant bandwidth part can be the same uplink bandwidth part identifier indicating the dormant bandwidth part (e.g., in the case of unpaired spectrum or TDD). The UE can apply the first SRS configuration information configured for the first bandwidth part activated from the dormancy, and can perform the SRS transmission based on the SRS transmission resource, period, or offset corresponding to the first SRS configuration information.

[0352] ■ As another approach, the current uplink bandwidth part or the last activated uplink bandwidth part can be activated as is.

[0353] ■ As another approach, if the first active downlink bandwidth part is not the dormant bandwidth part,

[0354] ◆ If the cell is deactivated before receiving the MAC control information indicating the cell activation or deactivation, or if the cell is configured active via RRC message in the cell configuration or configuration information,

[0355] ● The uplink bandwidth part or the downlink bandwidth part can be activated by the first active uplink bandwidth part identifier or the first active downlink bandwidth part identifier in the RRC configuration information, respectively.

[0356] ■ As another approach, if the first active downlink bandwidth part is the dormant bandwidth part,

[0357] ◆ The bandwidth part inactivity timer can be suspended.

[0358] ◆ If the cell is deactivated before receiving the MAC control information indicating the cell activation or deactivation, or if the cell is configured active via RRC message in the cell configuration or configuration information,

[0359] • The uplink bandwidth part or the downlink bandwidth part can be activated by the first active uplink bandwidth part identifier (or dormancy bandwidth part identifier) or the first active downlink bandwidth part identifier (or dormancy bandwidth part identifier) in the RRC configuration information, respectively. For example, if the first active downlink bandwidth part is configured as a dormancy bandwidth part, the first active uplink bandwidth part can also need to be configured as a dormancy bandwidth part.

[0360] • As another method, the downlink bandwidth part can be activated to the bandwidth part indicated by the first active downlink bandwidth part identifier (or dormancy bandwidth part identifier) in the RRC configuration information. The uplink bandwidth part can be activated to the bandwidth part indicated by the dormancy bandwidth part identifier (or first active uplink bandwidth part identifier) in the RRC configuration information.

[0361] ■ If PUCCH is configured for the activated bandwidth part, perform PUCCH transmission.

[0362] ■ For the above case, start or restart the bandwidth part inactivity timer or the cell dormancy timer. As another method, only when the bandwidth part dormancy timer or the cell dormancy timer is not configured, the bandwidth part inactivity timer or the cell dormancy timer can be started or restarted. If the bandwidth part dormancy timer or the cell dormancy timer can be configured via the RRC message, and when the timer expires, the bandwidth part or the cell can be put into dormancy. For example, the bandwidth part inactivity timer or the cell dormancy timer can be started or restarted only in the dormant bandwidth part or the cell.

[0363] ■ If there is a suspended type 1 configured transmission resource, the stored type 1 transmission resource can be initialized for use according to the original configuration. The type 1 configured transmission resource is a periodic transmission resource (uplink or downlink) pre-allocated via the RRC message, and refers to a transmission resource that can be activated for use via the RRC message.

[0364] ■ PHR is triggered for the bandwidth part.

[0365] ■ In the activated bandwidth part, the UE can report channel measurement results (CSI, CQI, PMI, RI, PTI, CRI, etc.) for the downlink according to the configuration of the base station.

[0366] ■ In the activated bandwidth part, monitor the PDCCH to read the indication of the base station.

[0367] ■ Monitor the PDCCH to read the cross scheduling for the activated bandwidth part.

[0368] ■Start or restart the bandwidth part inactivity timer. As another method, only when the bandwidth part dormancy timer is not configured, the bandwidth part inactivity timer can be started or restarted. If the bandwidth part dormancy timer can be configured via an RRC message, and when the timer expires, the bandwidth part can be put to sleep or switched to a dormant bandwidth part. For example, the bandwidth part inactivity timer can be started or restarted only in the dormant bandwidth part.

[0369] ■If the bandwidth part dormancy timer is configured for the bandwidth part,

[0370] ◆The bandwidth part dormancy timer is started or restarted for the bandwidth part.

[0371] In the present disclosure, when a deactivated bandwidth part (deactivated BWP), a bandwidth part, or a cell is deactivated, the UE operates as follows.

[0372] -If an indication of deactivating a bandwidth part (e.g., a downlink bandwidth part) of a current cell (PCell, PSCell, or SCell) or the cell is received via a DCI (L1 control signal) of a PDCCH, a MAC CE, or an RRC message, an indication of deactivating a bandwidth part (e.g., a downlink bandwidth part) or an indication of switching to a deactivated bandwidth part (if the indication is received via an L1 control signal of a PDCCH, it can be received on a PDCCH of the current cell by self-scheduling or can be received on a PDCCH of the cell in the PCell by cross-carrier scheduling) is received via a DCI (L1 control signal) of a PDCCH, a MAC CE, or an RRC message, a bandwidth part inactivity timer or a cell deactivation timer in the cell expires, an activated cell is deactivated, or a bandwidth part of the cell is deactivated, one or more of the following operations can be performed.

[0373] ■An uplink or downlink bandwidth part of the cell or the uplink or downlink bandwidth part indicated above can be deactivated.

[0374] ■The UE suspends a bandwidth part inactivity timer (e.g., a deactivation timer for a downlink bandwidth part) configured for the cell or the bandwidth part or running in the cell or the bandwidth part.

[0375] ■ Periodic downlink transmission resources (DL SPS or configured downlink assignment) or periodic uplink transmission resources (UL SPS or configured uplink grant type 2) configured for a cell or a bandwidth part can be cleared. The clearing of the transmission resources indicates the UE to store the configuration information (such as periodicity information configured via RRC message) but remove and no longer use the information about the periodic transmission resources indicated or activated via L1 signaling (e.g., DCI). The periodic transmission resources can be referred to as type 2 configured transmission resources. The clearing of the transmission resources can be performed only when the cell moves from the active state to the deactivated state. This is because, when the transition from the dormant state to the deactivated state is performed, there is no periodic transmission resource in the dormant state, so there is no need to clear the periodic transmission resources. As another method, the periodic transmission resources can be cleared only when the periodic downlink transmission resources or the periodic uplink transmission resources are configured or configured to be used.

[0376] ■ Periodic uplink transmission resources (configured uplink grant type 1 configured via RRC) configured for a cell or a bandwidth part can be suspended. The suspension of the transmission resources indicates the UE to store but no longer use the transmission resource configuration information configured via RRC message. The periodic transmission resources can be referred to as type 1 configured transmission resources. The clearing of the transmission resources can be performed only when the cell moves from the active state to the deactivated state. This is because, when the transition from the dormant state to the deactivated state is performed, there is no periodic transmission resource in the dormant state, so there is no need to clear the periodic transmission resources. As another method, the periodic transmission resources can be cleared only when the periodic downlink transmission resources or the periodic uplink transmission resources are configured or configured to be used.

[0377] ■ All HARQ buffers configured for a cell or a bandwidth part are emptied.

[0378] ■ PUSCH transmission resources configured for periodic channel measurement reporting (semi-persistent CSI reporting) of a cell or a bandwidth part are cleared if there are any.

[0379] ■ The UE does not perform SRS transmission for a cell or a bandwidth part.

[0380] ■ For a cell or a bandwidth part, the UE neither performs channel measurement (CSI, CQI, PMI, RI, PTI, CRI, etc.) for the downlink nor performs measurement reporting.

[0381] ■ Uplink data is not transmitted on the UL-SCH of a cell or a bandwidth part.

[0382] ■ Random access is not performed for a cell or a bandwidth part.

[0383] ■ The UE does not perform PDCCH monitoring in the cell or bandwidth part.

[0384] ■ The UE does not perform PDCCH monitoring in the cell or bandwidth part. In addition, even in the case of cross scheduling, PDCCH monitoring is not performed in the cell to be scheduled.

[0385] ■ PUCCH or SPUCCH transmission does not perform in the cell or bandwidth part.

[0386] In the present disclosure, the operation activity state, the deactivation state, or the dormancy state is operated, and when the cell or the bandwidth part is transferred or switched, the transfer or switching is performed in the bandwidth part level, in which, when the state transfer or switching occurs according to the bandwidth part level, the bandwidth part (downlink bandwidth part or uplink bandwidth part) for which the state transfer or switching is indicated performs the state transfer or switching according to the indication. For example, if the bandwidth part (downlink bandwidth part or uplink bandwidth part) is transferred from the active state to the dormant state, or is switched (activated) to the dormant bandwidth part, the bandwidth part can be transferred to the dormant state, or can be switched (or activated) to the dormant bandwidth part.

[0387] In the present disclosure, bandwidth part switching (BWP switching) refers to the following cases: when bandwidth part switching is indicated via DCI of PDCCH, if switching is indicated by a bandwidth part identifier during downlink assignment allocation, the downlink bandwidth part is switched to the bandwidth part indicated by the bandwidth part identifier; and when bandwidth part switching is indicated via DCI of PDCCH, if switching is indicated by a bandwidth part identifier during UL grant allocation, the uplink bandwidth part is switched to the bandwidth part indicated by the bandwidth part identifier. Since the DCI format of PDCCH itself is different from the format (format 1) for downlink assignment and the format (format 0) for UL grant, the UE can operate according to the DCI format even if the uplink and the downlink are not described separately.

[0388] The method of performing state transition according to the bandwidth part level and the bandwidth part operation according to the corresponding state proposed in the present disclosure can be extended and applied to various embodiments. In the following contents of the present disclosure, specific embodiments in which the proposed contents in the present disclosure are extended and applied will be described.

[0389] Figure 8 is a diagram illustrating a discontinuous reception (DRX) configuration or a DRX operation method capable of saving battery power of a UE according to an embodiment of the present disclosure.

[0390] Reference Figure 8, the base station can configure the UE for DRX functionality for a PCell, SCell, or PSCell via an RRC message, such as a DRX cycle, a starting point, an offset, or an on-duration (active time), as shown in Figure 6 In the present disclosure, it is considered that the DRX functionality is configured for a PCell, SPCell, or PSCell.

[0391] If the DRX functionality is configured for a PCell (or SPCell or PSCell), the UE can apply the DRX functionality considering a DRX cycle 8-03, a DRX starting time or offset. When applying the DRX functionality, the UE can monitor only in the PCell a PDCCH or a DCI of the PDCCH that can be received from the base station in an active time interval (on-duration or active time) 8-01 of the DRX. The UE can reduce battery consumption 8-02 by preventing the UE from monitoring the PDCCH or the DCI of the PDCCH outside the active time interval of the DRX functionality (outside the active time for an opportunity to receive the DRX).

[0392] The base station can configure the UE for a power saving functionality (power saving mode) via an RRC message (for example, as shown in Figure 6 If the power saving functionality is configured together with the DRX functionality, in the DRX functionality, the UE monitors the PDCCH outside the active time interval for a short time interval 8-04 configured via RRC before the active time 8-01 in which the UE needs to monitor the PDCCH, and the UE monitors and receives a wake-up signal (WUS) outside the active time interval. The base station can use a bit of a DCI of a PDCCH for the WUS signal to indicate whether the UE should perform PDCCH monitoring at a subsequent active time 8-05 and 8-07.

[0393] That is, the UE for which the power saving functionality or the DRX functionality has been configured can monitor the WUS signal for a short time interval 8-04 configured via an RRC message before each active time 8-05, and if a bit value of a DCI of a PDCCH related to a subsequent active time 8-05 and 8-07 is 0 (or 1) in the received WUS signal, the UE can be instructed not to monitor the PDCCH for the subsequent active time 8-07, or can be instructed not to monitor the PDCCH by preventing a timer corresponding to the subsequent active time from operating in the MAC layer. If the bit value of the DCI of the PDCCH related to the subsequent active time 8-05 and 8-07 is 1 (or 0) in the received WUS signal, the UE can be instructed to monitor the PDCCH for the subsequent active time 8-05 by causing the timer corresponding to the subsequent active time to operate in the MAC layer, or can be instructed to monitor the PDCCH.

[0394] In the active time interval, the UE can not monitor the WUS signal or can not monitor the PDCCH to detect the WUS signal.

[0395] When monitoring the WUS signal within a short time interval 8-04 configured via an RRC message before each active time 8-05, a UE for which a power saving function or a DRX function has been configured can detect the signal by checking the PDCCH via using a first RNTI identifier (e.g., PS-RNTI). The first RNTI identifier (e.g., PS-RNTI) can be configured for multiple UEs, and the base station can use the first RNTI identifier (e.g., PS-RNTI) to indicate to the multiple UEs whether to perform PDCCH monitoring in a subsequent active time interval 8-07 8-06.

[0396] When monitoring and detecting the PDCCH in the active time 8-05, a UE for which a power saving function or a DRX function has been configured can detect the signal via an RRC message based on a second RNTI (e.g., C-RNTI), a third RNTI (e.g., MCS-C-RNTI), or a fourth RNTI (e.g., SPS-C-RNTI or CS-RNTI) uniquely configured for the UE. The second RNTI (e.g., C-RNTI) can be used to indicate general UE scheduling, the third RNTI (e.g., MCS-C-RNTI) can be used to indicate a modulation and coding scheme of the UE, and the fourth RNTI (SPS-C-RNTI or CS-RNTI) can be used to indicate a periodic transmission resource of the UE.

[0397] Figure 9 is a schematic diagram illustrating a method of operating a dormant bandwidth part in an activated SCell according to an embodiment of the disclosure.

[0398] Reference Figure 6For the UE, via the RRC message, the base station can configure a plurality of SCells for carrier aggregation, allocate a corresponding SCell identifier, and configure a dormant bandwidth part for each SCell, or can configure a plurality of cell groups for dual connectivity, allocate a cell group identifier, and configure or indicate a cell group suspension indicator or configure a dormant bandwidth part for each cell group or a PSCell of each cell group. A plurality of SCells can be included in each SCell group so as to be configured, and each SCell group can include a plurality of SCells. An SCell group identifier can be allocated to each SCell group, and a plurality of SCell identifiers can be configured to be included in or mapped to each SCell group identifier. The SCell identifier value or the SCell group identifier value can be allocated with a predetermined bit value, or can have an integer value (or a natural number value). Alternatively, the PSCell of each cell group can be indicated by the cell group identifier.

[0399] Reference Figure 9 The base station can define a new bitmap for the DCI of the PDCCH transmitted in the PCell, can perform mapping so that each bit value of the bitmap indicates each SCell identifier value, each SCell group identifier value, a cell group (or secondary cell group) identifier, or a PSCell (or SCell) of a cell group (or secondary cell group), and for the SCell corresponding to the bit, the SCell belonging to the SCell group, the cell group (or secondary cell group), or the PSCell (or SCell) of the cell group (or secondary cell group), it can be indicated by defining each bit value whether to perform switching to the dormant bandwidth part, whether to activate the dormant bandwidth part, or whether to suspend or resume the cell group. It can be indicated for the SCell corresponding to the bit, the SCell belonging to the SCell group, the cell group (or secondary cell group) identifier, or the PSCell (or SCell) of the cell group (or secondary cell group) whether to switch from the dormant bandwidth part to the normal bandwidth part (for example, the first active bandwidth part activated from dormancy) or whether to activate the normal bandwidth part (for example, the first active bandwidth part activated from dormancy).

[0400] Reference Figure 9, the PCell 9-01 can include a first normal BWP 9-11 and a second normal BWP 9-12. After receiving the DCI of the PDCCH in the PCell 9-01, the UE can determine whether a bitmap exists while reading the DCI in 9-05, the bitmap including an indication for a bandwidth part of an SCell or an SCell group (e.g., switching or activation to a dormant bandwidth part, or switching or activation to a normal bandwidth part), or an indication to suspend or resume a cell group (or secondary cell group) or a PSCell (or SCell) of the cell group (or secondary cell group). If the bitmap exists, for an SCell indicated by each bit of the bitmap, an SCell 9-02 and 9-03 belonging to an SCell group, a PSCell (or SCell) of a cell group (or secondary cell group) or a cell group (or secondary cell group), according to a bit value, a bandwidth part can be switched or activated, or the cell group can be suspended or resumed. For example, if a bit of the bitmap indicates a first SCell (or a first SCell identifier) 9-02, a PSCell (or SCell) of a cell group (or secondary cell group) or a cell group (or secondary cell group), or indicates an SCell group including the first SCell (or the first SCell identifier), and the bit value is 0 (or 1), for the first SCell 9-02, a PSCell (or SCell) of a cell group (or secondary cell group) or a cell group (or secondary cell group), the UE can activate the bandwidth part 9-21 to the dormant bandwidth part 9-22, or switch the current bandwidth part to the dormant bandwidth part 9-22, or when the current bandwidth part is not the dormant bandwidth part, the UE can switch or activate 9-25 the currently activated bandwidth part 9-21 to the dormant bandwidth part 9-22, or can suspend or deactivate the cell group. As another method, power consumption of the UE can be reduced by maintaining the cell group (or secondary cell group) or the PSCell (or SCell) of the cell group (or secondary cell group) as it is, applying the second DRX configuration information or the second SRS configuration information proposed in the present disclosure, and performing PDCCH monitoring or SRS transmission with a long cycle.

[0401] Reference Figure 9After receiving the DCI of the PDCCH in the PCell 9-01, the UE can determine whether a bitmap exists at the same time of reading the DCI, the bitmap including an indication for a bandwidth part of an SCell or an SCell group (e.g., switching or activating to a dormant bandwidth part, or switching or activating to a normal bandwidth part), an indication for a bandwidth part of a cell group (or a secondary cell group) or a PSCell (or an SCell) of the cell group (or the secondary cell group), or an indication for suspending or resuming the cell group. If the bitmap exists, for each SCell indicated by a bit of the bitmap, an SCell 9-02 and 9-03 belonging to an SCell group, a cell group (or a secondary cell group), or a PSCell (or an SCell) of the cell group (or the secondary cell group), according to a bit value, a bandwidth part can be switched or activated, or the cell group can be suspended or resumed. For example, when a bit of the bitmap indicates a second SCell (or a second SCell identifier) 9-03, or indicates an SCell group (or an SCell identifier) including the second SCell, a cell group (or a secondary cell group), or a PSCell (or an SCell) of the cell group (or the secondary cell group), and the bit value is 1 (or 0), if a currently activated bandwidth part of the second SCell 9-03 is a dormant bandwidth part 9-32, if the currently activated bandwidth part is not a normal bandwidth part, or if the current bandwidth part (or cell) is activated and the current bandwidth part is activated to the dormant bandwidth part 9-32 (or is activated to a bandwidth part other than the normal bandwidth part), the UE can switch or activate 9-35 a bandwidth part of the second SCell 9-03 to a bandwidth part 9-33 configured via an RRC message (e.g., a first active bandwidth part activated from dormancy), or can resume or activate the cell group. When the SCell, the SCell belonging to the SCell group, the cell group (or the secondary cell group), or the PSCell (or the SCell) of the cell group (or the secondary cell group) indicated by the bit should be switched or activated to a bandwidth part other than the dormant bandwidth part, or the cell group should be resumed, due to the bit value being 1 (or 0), the bit value can not be applied (or can be ignored or can not be read) for the SCell or each SCell belonging to the SCell group, if the SCell is deactivated, or if the SCell is activated and the activated bandwidth part is not the dormant bandwidth part (or is the normal bandwidth part), or the bit value can not be applied (or can be ignored or can not be read) if the cell group (or the secondary cell group) or the PSCell (or the SCell) of the cell group (or the secondary cell group) is already activated or resumed.When the SCell, the SCell belonging to the SCell group, the cell group (or the secondary cell group) or the PSCell (or the SCell) of the cell group (or the secondary cell group) indicated by the bit should be switched or activated to the dormant bandwidth part or the cell group should be resumed due to the bit value being 0 (or 1), the bit value can not be applied (or can be ignored or can not be read) for the SCell or each SCell belonging to the SCell group if the SCell is active and the activated bandwidth part is the dormant bandwidth part, or the bit value can not be applied (or can be ignored or can not be read) if the cell group (or the secondary cell group) or the PSCell (or the SCell) of the cell group (or the secondary cell group) has been suspended or deactivated.

[0402] Figure 10 is shown to implement a reference Figure 9 a first embodiment of the method of operating the dormant bandwidth part in the activated SCell is described.

[0403] In the first embodiment, with reference to Figure 6 For carrier aggregation, the base station can configure a plurality of SCells for the UE via the RRC message, assign a corresponding SCell identifier, configure a dormant bandwidth part for the corresponding SCell, and can not configure a bandwidth part for some SCells, or for dual connectivity, the base station can configure one or more cell groups and respectively configure a cell group identifier or a cell group state, or can configure a dormant bandwidth part for the PSCell (or SCell) of each cell group, and can not configure a dormant bandwidth part for some cells. A plurality of SCells can be included in each SCell group to be configured, and each SCell group can include a plurality of SCells. An SCell group identifier can be assigned to each SCell group, and a plurality of SCell identifiers can be configured to be included in or mapped to each SCell group identifier. The SCell identifier value, the SCell group identifier value, or the cell group (or secondary cell group) identifier can be assigned a predetermined bit value, or can have an integer value (or a natural number value). The SCell group or the SCell group identifier configured for or applying the first embodiment can be indicated as a first SCell group. In the first SCell group, in the first embodiment, the UE can monitor the DCI of the PDCCH in a short time interval (outside the active time) or in a time interval outside the activation time interval, and the group identifier can be indicated to apply the operation indicated by the bitmap value of the received DCI.

[0404] With reference to Figure 10 As Figure 6As illustrated, the base station can configure the power saving function or the DRX function for each of the plurality of UEs via the RRC message. Before the active time interval 10-30 of the DRX cycle in the PCell 10-1 or the SPCell, the base station can configure time information for a short time interval 10-02 in which the first DCI format or the WUS signal should be detected, or configuration information for the first DCI format for each UE via the RRC message, and when the UE detects the first DCI format in the short time interval 10-02 in the PCell or the SPCell, the base station can configure the position of the bitmap including the indication of the first SCell group for each UE in the first DCI format via the RRC message. The base station can configure the UE identifier (e.g., PS-RNTI) or the search space of the PDCCH monitoring for detecting the first DCI format during the short time interval 10-02 for each UE via the RRC message. Since the UE does not monitor the DCI of the PDCCH when the dormancy bandwidth part of the SCell or the PSCell is performed switching or activation, it is very inefficient for the UE to receive the DCI or the bitmap of the PDCCH proposed in the present disclosure in the SCell rather than the PCell or the SPCell. Therefore, it is proposed to monitor the DCI of the PDCCH proposed in the present disclosure in the PCell or the SPCell.

[0405] For example, the base station can configure the power saving function or the DRX function for a plurality of UEs as described above, can transmit the first DCI format in the PDCCH transmission resource in the short time interval 10-02 configured before the subsequent active time interval 10-03 of the DRX cycle configured for the UE, and the first DCI format can include the bit Figure 10 -04 and 10-05, the bit Figure 10 -04 and 10-05 include indication information of the dormancy bandwidth part of the first SCell group configured for each of the plurality of UEs, or the suspension or resumption of the cell group (or the secondary cell group) or the PSCell (or the SCell) of the cell group (or the secondary cell group).

[0406] As described above, the first UE 10-10 to which the information configured via the RRC message has been applied can perform PDCCH monitoring, and can detect the first DCI format from the base station in the search space based on the PS-RNTI as the identifier configured in the short time interval 10-02 before the subsequent active time interval 10-30 of the DRX cycle. If the first DCI format 10-03 is detected, the first UE can read the bit Figure 10 -04 from the first DCI format 10-03 via the time information or the position information configured in the RRC message, the bit Figure 10-04 includes indication information of a dormant bandwidth part of a first SCell group, a cell group (or a secondary cell group), or a PSCell (or an SCell) of a cell group (or a secondary cell group) of the first UE, or information indicating suspension or resumption of the cell group (or the secondary cell group) or the PSCell (or the SCell) of the cell group (or the secondary cell group). The length of the bitmap can be configured to be equal to the number of the first SCell group, the cell group (or the secondary cell group), or the PSCell (or the SCell) of the cell group (or the secondary cell group) configured for the first UE, and can be configured to be a maximum predetermined number (e.g., 5). Each bit value of the bitmap can be mapped to each first SCell group in ascending order of the SCell group identifier value of the corresponding first SCell group configured for the first UE, starting from the right bit of the bitmap (e.g., from the least significant bit (LSB)), so as to be indicated. As another method, each bit value of the bitmap can be mapped to each first SCell group in descending order of the SCell group identifier value of the corresponding first SCell group configured for the first UE, starting from the right bit of the bitmap (e.g., from the least significant bit (LSB)), so as to be indicated. As another method, each bit value of the bitmap can be mapped to each first SCell group in ascending order of the SCell group identifier value of the corresponding first SCell group configured for the first UE, starting from the left bit of the bitmap (e.g., from the most significant bit (MSB)), so as to be indicated. As another method, each bit value of the bitmap can be mapped to each first SCell group in descending order of the SCell group identifier value of the corresponding first SCell group configured for the first UE, starting from the left bit of the bitmap (e.g., from the most significant bit (MSB)), so as to be indicated. A new bit is defined in the first DCI format of the PDCCH, and the new bit can be used as information indicating suspension or resumption of the cell group (or the secondary cell group) or the PSCell (or the SCell) of the cell group (or the secondary cell group).

[0407] The second UE 10-20 can perform PDCCH monitoring, and can detect the first DCI format from the base station in the search space based on the PS-RNTI which is the identifier configured in the short time interval 10-02 before the subsequent active time interval 10-30 of the DRX cycle. If the first DCI format 10-03 is detected, the first UE can read the bits Figure 10 -05.

[0408] If the bits Figure 10-11When the bit value of the bitmap is 1, the bit value 1 can indicate performing switching or activation to a normal bandwidth part (e.g., a first active bandwidth part activated from dormancy) for each activated SCell among the SCells included in the first SCell group corresponding to the bit. As another method, when the bit value of the bitmap is 1, the UE can indicate according to the bit value 1 that, if the current or activated bandwidth part is a dormant bandwidth part (or is not a normal bandwidth part) for each activated SCell among the SCells included in the first SCell group corresponding to the bit, switching or activation to a normal bandwidth part (e.g., a first active bandwidth part activated from dormancy) is performed, otherwise (if the current or activated bandwidth part is not a dormant bandwidth part (or is a normal bandwidth part) for each activated SCell among the SCells included in the first SCell group corresponding to the bit), the UE can maintain (or continue to use, apply, or activate) the current active bandwidth part as it is. As another method, when the bit value of the bitmap is 1, the UE can indicate according to the bit value 1 that performing switching or activation from a dormant bandwidth part to a normal bandwidth part (e.g., a first active bandwidth part activated from dormancy) for each activated SCell among the SCells included in the first SCell group corresponding to the bit, or can indicate maintaining (or continuing to use, applying, or activating) the current active bandwidth part as it is.

[0409] When the bit value of the bitmap is 1, the bit value 1 can indicate performing switching or activation to a normal bandwidth part (e.g., a first active bandwidth part activated from dormancy) for each activated SCell among the SCells included in the first SCell group corresponding to the bit. As another method, when the bit value of the bitmap is 1, the UE can indicate according to the bit value 1 that, if the current or activated bandwidth part is a dormant bandwidth part (or is not a normal bandwidth part) for each activated SCell among the SCells included in the first SCell group corresponding to the bit, switching or activation to a normal bandwidth part (e.g., a first active bandwidth part activated from dormancy) is performed, otherwise (if the current or activated bandwidth part is not a dormant bandwidth part (or is a normal bandwidth part) for each activated SCell among the SCells included in the first SCell group corresponding to the bit), the UE can maintain (or continue to use, apply, or activate) the current active bandwidth part as it is. As another method, when the bit value of the bitmap is 1, the UE can indicate according to the bit value 1 that performing switching or activation from a dormant bandwidth part to a normal bandwidth part (e.g., a first active bandwidth part activated from dormancy) for each activated SCell among the SCells included in the first SCell group corresponding to the bit, or can indicate maintaining (or continuing to use, applying, or activating) the current active bandwidth part as it is.

[0410] After receiving the DCI of the PDCCH in the PCell, the UE can determine whether there is a bitmap including an indication of a bandwidth part of a cell group (or a secondary cell group) or a bandwidth part of a PSCell (or an SCell) of a cell group (or a secondary cell group) or an indication of suspending or resuming a cell group while reading the DCI. If there is a bitmap, for a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) indicated by each bit of the bitmap, according to a bit value, a bandwidth part can be switched or activated or a cell group can be suspended or resumed. For example, if a bit of the bitmap indicates a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) and the bit value is 1 (or 0), the UE can resume or activate the cell group. When a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) indicated by the bit should be switched or activated to a bandwidth part other than a dormant bandwidth part because the bit value is 1 (or 0), or when the cell group should be resumed, the bit value can not be applied (or can be ignored or can not be read) if the cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) has already been resumed. For example, if a bit of the bitmap indicates a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) and the bit value is 0 (or 1), the UE can switch or activate a bandwidth part of a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) to a dormant bandwidth part, or can suspend or deactivate the cell group. When a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) indicated by the bit should be switched or activated to a dormant bandwidth part because the bit value is 0 (or 1), or the cell group should be resumed, the bit value can not be applied (or can be ignored or can not be read) for an SCell or each SCell belonging to an SCell group if the SCell is active and the activated bandwidth part is a dormant bandwidth part, or the bit value can not be applied (or can be ignored or can not be read) if the cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) has already been suspended or deactivated.

[0411] The first embodiment is as described above, and in the first embodiment, the first DCI format of the PDCCH proposed in the first embodiment can be used in a short time interval, and the UE does not accompany a downlink transmission resource (e.g., PDSCH) or an uplink transmission resource (e.g., PUSCH). Accordingly, in the first embodiment, the UE can receive the first DCI format of the PDCCH, and can not transmit ACK or NACK information (e.g., HARQ ACK or NACK) in response thereto.

[0412] Figure 11 is a diagram illustrating implementation of a reference Figure 9 FIG. 2 is a diagram illustrating a second embodiment of a method of operating a dormant bandwidth part in an activated SCell according to an embodiment of the disclosure.

[0413] In the second embodiment, with reference to Figure 6 For carrier aggregation, the base station can configure a plurality of SCells for the UE via an RRC message and allocate a corresponding SCell identifier, or for dual connectivity, the base station can configure one or more cell groups and configure a cell group identifier or a cell group state, respectively, or can configure a dormant bandwidth part for a PSCell (or SCell) of each cell group and can not configure a dormant bandwidth part for some cells. A dormant bandwidth part can be configured for each cell, and a bandwidth part can not be configured for some cells. A plurality of SCells can be included in each SCell group so as to be configured, and each SCell group can include a plurality of SCells. An SCell group identifier can be allocated to each SCell group, and a plurality of SCell identifiers can be configured to be included in or mapped to each SCell group identifier. The SCell identifier value, the SCell group identifier value, or the cell group (or secondary cell group) identifier can be allocated with a predetermined bit value, or can have an integer value (or a natural number value). The SCell group or the SCell group identifier configured for or applying the second embodiment can be indicated as a second SCell group. In the second SCell group in the second embodiment, the UE can monitor the DCI of the PDCCH in the activation time interval (within the active time), and the group identifier can be indicated to apply the operation indicated by the bitmap value of the received DCI.

[0414] With reference to Figure 11 As Figure 6As illustrated, the base station can configure the UE with the power saving function or the DRX function via the RRC message. The configuration information for the second DCI format (e.g., DCI format 0_1 or DCI format 1_1) that the UE should detect in the active time interval 11-30 of the DRX cycle of the PCell 11-01 or the SPCell can be configured via the RRC message. When the UE detects the second DCI format in the PCell or the SPCell, the UE can determine whether the second DCI format includes the bitmap containing the indication of the second SCell group of the UE. The base station can configure the UE with the UE identifier 11-02 (e.g., C-RNTI, MCS-C-RNTI, or SPS-C-RNTI (or CS-RNTI)) or the search space of the PDCCH monitoring for detecting the second DCI format in the active time interval 11-30 via the RRC message. Since the UE does not monitor the DCI of the PDCCH when the switching or activation of the dormant bandwidth part of the SCell or the PSCell is performed, it is very inefficient for the UE to receive the DCI or the bitmap of the PDCCH proposed in the disclosure in the SCell rather than the PCell or the SPCell. Therefore, it is proposed to monitor the DCI of the PDCCH proposed in the disclosure in the PCell or the SPCell.

[0415] For example, the base station can transmit the second DCI format 11-03 in the transmission resource of the PDCCH in the active time interval 11-30 in the PCell or the SPCell as described above, and the second DCI format can include the bit Figure 11 -04, the bit Figure 11 -04 includes the indication information of the dormant bandwidth part of the second SCell group configured for the UE or the suspension or resumption of the PSCell (or SCell) of the cell group (or secondary cell group) or the cell group (or secondary cell group).

[0416] As described above, the first UE 11-10 to which the information configured via the RRC message has been applied can perform the PDCCH monitoring and can detect the second DCI format 11-03 from the base station in the search space based on the UE identifier (e.g., C-RNTI, MCS-C-RNTI, or SPS-C-RNTI (or CS-RNTI)) that is the identifier configured in the active time interval 11-30 of the DRX cycle. If the second DCI format 11-03 is detected, the first UE can read the bit Figure 11 -04, the bit Figure 11-04 includes indication information of the dormant bandwidth portion of the PSCell (or SCell) of the second SCell group, cell group (or secondary cell group), or cell group (or secondary cell group) of the first UE, or information indicating the suspension or resumption of the PSCell (or SCell) of the cell group (or secondary cell group). The length of the bitmap can be configured to be equal to the number of the second SCell group, cell group (or secondary cell group), or cell group (or secondary cell group) of the first UE, and can be configured to a maximum predetermined number (e.g., 5). Each bit value of the bitmap can be mapped to each second SCell group starting from the right bit of the bitmap (e.g., from the least significant bit (LSB)) in ascending order of the SCell group identifier value of the corresponding second SCell group configured for the first UE, for indication purposes. As another method, each bit value of the bitmap can be mapped from the right bit of the bitmap (e.g., from the least significant bit (LSB)) to each second SCell group in descending order of the SCell group identifier values ​​configured for the first UE, for indication. Alternatively, each bit value of the bitmap can be mapped from the left bit of the bitmap (e.g., from the most significant bit (MSB)) to each second SCell group in ascending order of the SCell group identifier values ​​configured for the first UE, for indication. Alternatively, each bit value of the bitmap can be mapped from the left bit of the bitmap (e.g., from the most significant bit (MSB)) to each second SCell group in descending order of the SCell group identifier values ​​configured for the first UE, for indication. A new bit is defined in the second DCI format of the PDCCH, and this new bit can be used as information indicating the suspension or resumption of a PSCell (or SCell) of a cell group (or secondary cell group).

[0417] If the bit Figure 11-11 If bits 11-12, 11-13, 11-14, or 11-15 are 0, then bit value 0 can indicate that a switch to or activation of the sleep bandwidth portion is performed for each active SCell (if a sleep bandwidth portion is configured) included in the second SCell group corresponding to that bit. Alternatively, if the bit value of the bitmap is 0, the UE can, based on bit value 0, indicate that if, for each active SCell included in the second SCell group corresponding to that bit, the active bandwidth portion is not the sleep bandwidth portion (or the normal bandwidth portion), then a switch to or activation of the sleep bandwidth portion is performed.

[0418] When the bit value of the bitmap is 1, the bit value 1 can indicate to perform a switch or activation to a normal bandwidth part (e.g., a first active bandwidth part activated from dormancy) for each activated SCell among the SCells included in the second SCell group corresponding to the bit. As another approach, when the bit value of the bitmap is 1, the UE can be instructed by the bit value 1 to, if the current or activated bandwidth part is a dormancy bandwidth part (or not a normal bandwidth part) for each activated SCell among the SCells included in the second SCell group corresponding to the bit, perform a switch or activation to a normal bandwidth part (e.g., a first active bandwidth part activated from dormancy), otherwise (if the current or activated bandwidth part is not a dormancy bandwidth part (or is a normal bandwidth part) for each activated SCell among the SCells included in the second SCell group corresponding to the bit), the UE can maintain (or continue to use, apply, or activate) the current active bandwidth part as is. As another approach, when the bit value of the bitmap is 1, the UE can be instructed by the bit value 1 to perform a switch or activation from a dormancy bandwidth part to a normal bandwidth part (e.g., a first active bandwidth part activated from dormancy) for each activated SCell among the SCells included in the second SCell group corresponding to the bit, or can be instructed to maintain (or continue to use, apply, or activate) the current active bandwidth part as is.

[0419] After receiving the DCI of the PDCCH in the PCell, the UE can determine whether there is a bitmap including an indication of a bandwidth part of a cell group (or a secondary cell group) or a bandwidth part of a PSCell (or an SCell) of a cell group (or a secondary cell group) or an indication of suspending or resuming a cell group while reading the DCI. If there is a bitmap, for a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) indicated by each bit of the bitmap, according to a bit value, a bandwidth part can be switched or activated or a cell group can be suspended or resumed. For example, if a bit of the bitmap indicates a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) and the bit value is 1 (or 0), the UE can resume or activate the cell group. When a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) indicated by the bit should be switched or activated to a bandwidth part other than a dormant bandwidth part because the bit value is 1 (or 0), or when the cell group should be resumed, the bit value can not be applied (or can be ignored or can not be read) if the cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) has already been resumed. For example, if a bit of the bitmap indicates a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) and the bit value is 0 (or 1), the UE can switch or activate a bandwidth part of a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) to a dormant bandwidth part, or can suspend or deactivate the cell group. When a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) indicated by the bit should be switched or activated to a dormant bandwidth part because the bit value is 0 (or 1), or the cell group should be resumed, the bit value can not be applied (or can be ignored or can not be read) for an SCell or each SCell belonging to an SCell group if the SCell is active and the activated bandwidth part is a dormant bandwidth part, or the bit value can not be applied (or can be ignored or can not be read) if the cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) has already been suspended or deactivated.

[0420] The second embodiment exemplifies the above-described operation, and a second DCI format of the PDCCH proposed in the second embodiment can be used in the activation time interval, and the PCell of the UE is further accompanied by a downlink transmission resource (e.g., PDSCH) or an uplink transmission resource (e.g., PUSCH) for the SPCell. Accordingly, in the second embodiment, the UE can receive the second DCI format of the PDCCH, and can transmit ACK or NACK information (e.g., HARQ ACK or NACK) for the scheduling information (downlink transmission resource or uplink transmission resource) of the PCell or the SPCell indicated by the second DCI format, and thus in the second embodiment, the base station can determine whether the UE has successfully received the indication of the second DCI format.

[0421] Referring to the above-described Figure 6 , the base station can configure each of the first SCell group configuration information applicable to the first embodiment and the second SCell group configuration information applicable to the second embodiment proposed in the present disclosure for the UE in an RRCSetup message 6-25, an RRCResume message, or an RRCReconfiguration message 6-45 of an RRC connection configuration. In the RRC message, the base station can allocate an SCell identifier to each SCell of the UE, can allocate a first SCell group identifier to each group of the first SCell group, and can allocate a second SCell group identifier to each group of the second SCell group. The base station can allocate a first SCell group set identifier indicating the first SCell group, and can allocate a second SCell group set identifier indicating the second SCell group. The SCell identifier can be included in or mapped to the first SCell group or the second SCell group, respectively. Only when the SCell is configured with a dormant bandwidth part (e.g., a downlink dormant bandwidth part), the base station can configure the SCell or the SCell identifier to be included in or mapped to the first SCell group or the second SCell group.

[0422] Figure 12 is a diagram illustrating a method of operating a dormant bandwidth part in an activated SCell according to a third embodiment of the present disclosure. Figure 9

[0423] In the third embodiment, referring to Figure 6 ​For carrier aggregation, the base station can configure a plurality of SCells for the UE via an RRC message, allocate a corresponding SCell identifier, configure a dormant bandwidth part for the corresponding SCell, and can not configure a bandwidth part for some SCells, or for dual connectivity, the base station can configure one or more cell groups and respectively configure a cell group identifier or a cell group state identifier, or can configure a dormant bandwidth part for a PSCell (or SCell) of each cell group, and can not configure a dormant bandwidth part for some cells. The SCell identifier value can be allocated with a predetermined bit value, or can have an integer value (or a natural number value). In order to operate or apply the third embodiment, the SCell identifier or the cell group (or secondary cell group) identifier configured in the RRC message can be used. In the third embodiment, the SCell identifier or the cell group (or secondary cell group) identifier can indicate that the UE monitors the DCI of the PDCCH in the activation time interval (within the active time), and can indicate the identifier of each SCell, each SCell identifier, or a cell group (or secondary cell group) to apply the operation indicated by the bitmap value of the received DCI.

[0424] Reference Figure 12 As Figure 6 indicated, the base station can configure the UE with a power saving function or a DRX function via an RRC message. Configuration information for a third DCI format (e.g., DCI format 1_1) that the UE should detect in an active time interval 12-30 of a DRX cycle of the PCell 12-01 or the SpCell can be configured via an RRC message. When the UE detects the third DCI format in the PCell or the SpCell, the UE can determine whether the third DCI format includes a bitmap including an indication of each SCell, PSCell, or SCell identifier of the UE.

[0425] The third DCI format can include a transmission resource type (resourceAllocation) field, a field for frequency transmission resource allocation (frequency domain resource assignment), a modulation and coding scheme (MCS) field, a new data indicator (NDI) field, a redundancy version (RV) field, a HARQ process number field, an antenna port field, a DMRS sequence initialization (DMRS SI) field, etc.

[0426] In the detected third DCI format, if the type indicated by the transmission resource type field (e.g., resourceAllocation) is the first type (e.g., resourceAllocationType0) and all bits of the field for frequency transmission resource allocation are 0 or a specific value, or if the type indicated by the transmission resource type field (e.g., resourceAllocation) is the second type (e.g., resourceAllocationType1) and all bits of the field for frequency transmission resource allocation are 1 or a specific value, the UE can not interpret the bits or fields located thereafter as a modulation and coding scheme (MCS) field, a new data indicator (NDI) field, a redundancy version (RV) field, a HARQ process number field, an antenna port field, or a DMRS sequence initialization (DMRS SI) field, and the UE can consider a bitmap field indicating switching or activation to a dormant bandwidth part or indicating switching or activation from a dormant bandwidth part to a normal bandwidth part for each SCell or PSCell configured for the UE, or as bits indicating suspension or resumption of a cell group (or secondary cell group) or a PSCell (or SCell) of a cell group (or secondary cell group), the bitmap field and bits can be read and the information indicated by the bitmap can be applied. However, in the detected third DCI format, if the type indicated by the transmission resource type field (e.g., resourceAllocation) is the first type (e.g., resourceAllocationType0) and all bits of the field for frequency transmission resource allocation are neither 0 nor a specific value, or if the type indicated by the transmission resource type field (e.g., resourceAllocation) is the second type (e.g., resourceAllocationType1) and all bits of the field for frequency transmission resource allocation are neither 1 nor a specific value, the UE can interpret the bits or fields located thereafter as a modulation and coding scheme (MCS) field, a new data indicator (NDI) field, a redundancy version (RV) field, a HARQ process number field, an antenna port field, or a DMRS sequence initialization (DMRS SI) field, and they can be read and applied.

[0427] In the case where the UE performs scrambling or detection with the second UE identifier (e.g., SPS-C-RNTI (or CS-RNTI)) upon detecting the third DCI field of the PDCCH, if the type indicated by the transmission resource type field (e.g., resourceAllocation) is the first type (e.g., resourceAllocationType0) and all bits of the field for frequency transmission resource allocation are 0 in the third DCI format, or if the type indicated by the transmission resource type field (e.g., resourceAllocation) is the second type (e.g., resourceAllocationType1) and all bits of the field for frequency transmission resource allocation are 1 in the third DCI format, a special command to activate or clear the periodic transmission resource configured for the UE can be indicated.

[0428] Accordingly, the third embodiment proposes that only in the case where the third DCI field of the PDCCH is detected by scrambling with the first UE identifier (e.g., C-RNTI or MCS-C-RNTI), if the type indicated by the transmission resource type field (e.g., resourceAllocation) is the first type (e.g., resourceAllocationType0) and all bits of the field for frequency transmission resource allocation are 0 or a specific value in the third DCI format, or if the type indicated by the transmission resource type field (e.g., resourceAllocation) is the second type (e.g., resourceAllocationType1) and all bits of the field for frequency transmission resource allocation are 1 or a specific value in the third DCI format, the subsequent field can be interpreted as a bitmap indicating the dormant bandwidth part operation of each SCell of the UE, or as a bit indicating the suspension or resumption of the cell group (or secondary cell group) or the PSCell (or SCell) of the cell group (or secondary cell group).

[0429] The base station can configure the UE identifier (e.g., C-RNTI or MCS-C-RNTI) or the search space for PDCCH monitoring for the UE via an RRC message for detecting the third DCI format in the activation time interval 12-30. The time information for the activation time interval 12-30 can be configured in the time interval 12-02.

[0430] For example, the base station can transmit the third DCI format 12-03 in the transmission resource of the PDCCH of the activation time interval 12-30 in the PCell or the SPCell as described above, and the third DCI format can include bits Figure 12 -04, the bitsFigure 12 -04 includes indication information of a dormant bandwidth part for a third SCell group configured for the UE or a bit indicating suspension or resumption of a PSCell (or SCell) of a cell group (or secondary cell group) or a cell group (or secondary cell group).

[0431] As described above, the first UE 12-10 to which information configured via an RRC message has been applied can perform PDCCH monitoring, and can detect 12-03 a third DCI format from the base station in a search space based on a first UE identifier (e.g., C-RNTI or MCS-C-RNTI) that is an identifier configured in an active time interval 12-30 of a DRX cycle (or by being scrambled with the first UE identifier). If the third DCI format 12-03 is detected, and if in the third DCI format 12-03, the type indicated by the transmission resource type field (e.g., resourceAllocation) is the first type (e.g., resourceAllocationType0), and all bits of the field for frequency transmission resource allocation are 0, or if in the third DCI format 12-03, the type indicated by the transmission resource type field (e.g., resourceAllocation) is the second type (e.g., resourceAllocationType1), and all bits of the field for frequency transmission resource allocation are 1 12-20, the first UE can interpret the subsequent field as a bitmap indicating dormant bandwidth part operation of each SCell of the UE, and can read bits Figure 12 -04, the bits Figure 12 -04 include indication information of a dormant bandwidth part for a plurality of SCells (or SCell identifiers) configured for the first UE, or a bit indicating suspension or resumption of a PSCell (or SCell) of a cell group (or secondary cell group) or a cell group (or secondary cell group).

[0432] Since the length of the bitmap can have a fixed length, such as 15 bits or 16 bits, by replacing the existing MCS field, NDI field, RV field, HARQ process number field, antenna port field, or DMRS SI field to interpret the length of the bitmap when the above proposed conditions are satisfied.

[0433] In a third embodiment proposed in the present disclosure, in the bitmap mapping method, for example, in the first bitmap method, each bit value of the bitmap can be mapped with each SCell in ascending order or descending order of the SCell identifier value of the corresponding SCell configured for the first UE, starting from the right bit (e.g., from the least significant bit (LSB)) or the left bit (e.g., from the most significant bit (MSB)) of the bitmap, in order to be indicated. As another method, in the first bitmap method, each bit value of the bitmap can be mapped with each SCell in ascending order of the SCell identifier value of the corresponding SCell of the cell group (Master Cell Group (MCG) or Secondary Cell Group (SCG)) configured for the first UE, starting from the right bit (e.g., from the least significant bit (LSB)) of the bitmap, in order to be indicated. If the UE receives the third DCI format from the PCell, only the SCells belonging to the MCG cell group can be mapped with the bitmap in ascending order of the SCell identifier value. If the UE receives the third DCI format from the PSCell, only the SCells belonging to the SCG cell group can be mapped with the bitmap in ascending order of the SCell identifier value. As mentioned above, the reason for limiting the mapping with the bitmap to the SCells belonging to one cell group is that the number of SCell identifiers that can be configured for one UE is 32, and the bitmap is 15 bits or 16 bits.

[0434] As another method, in the first bitmap method, each bit value of the bitmap can be mapped with each SCell in descending order of the SCell identifier value of the corresponding SCell of the cell group (Master Cell Group (MCG) or Secondary Cell Group (SCG)) configured for the first UE, starting from the right bit (e.g., from the least significant bit (LSB)) of the bitmap, in order to be indicated. If the UE receives the third DCI format from the PCell, only the SCells belonging to the MCG cell group can be mapped with the bitmap in ascending order of the SCell identifier value. If the UE receives the third DCI format from the PSCell, only the SCells belonging to the SCG cell group can be mapped with the bitmap in descending order of the SCell identifier value. As mentioned above, the reason for limiting the mapping with the bitmap to the SCells belonging to one cell group is that the number of SCell identifiers that can be configured for one UE is 32, and the bitmap is 15 bits or 16 bits.

[0435] As another method, in the first bitmap method, each bit value of the bitmap can be mapped to each SCell in ascending order of the SCell identifier value of the corresponding SCell of the cell group (Master Cell Group (MCG) or Secondary Cell Group (SCG)) configured for the first UE, starting from the left bit (e.g., from the most significant bit (MSB)) of the bitmap, in order to be indicated. If the UE receives the third DCI format from the PCell, only the SCells belonging to the MCG cell group can be mapped to the bitmap in ascending order of the SCell identifier value. If the UE receives the third DCI format from the PSCell, only the SCells belonging to the SCG cell group can be mapped to the bitmap in ascending order of the SCell identifier value. As described above, the reason for limiting the mapping to the bitmap to the SCells belonging to one cell group is that the number of SCell identifiers that can be configured for one UE is 32, and the bitmap is 15 bits or 16 bits.

[0436] As another method, in the first bitmap method, each bit value of the bitmap can be mapped to each SCell in descending order of the SCell identifier value of the corresponding SCell of the cell group (Master Cell Group (MCG) or Secondary Cell Group (SCG)) configured for the first UE, starting from the left bit (e.g., from the most significant bit (MSB)) of the bitmap, in order to be indicated. If the UE receives the third DCI format from the PCell, only the SCells belonging to the MCG cell group can be mapped to the bitmap in ascending order of the SCell identifier value. If the UE receives the third DCI format from the PSCell, only the SCells belonging to the SCG cell group can be mapped to the bitmap in descending order of the SCell identifier value. As described above, the reason for limiting the mapping to the bitmap to the SCells belonging to one cell group is that the number of SCell identifiers that can be configured for one UE is 32, and the bitmap is 15 bits or 16 bits. A new bit is defined in the first DCI format of the PDCCH, and the new bit can be used as information indicating the suspension or resumption of the cell group (or secondary cell group) or the PSCell (or SCell) of the cell group (or secondary cell group).

[0437] If the rule of mapping starting from the left bit or the right bit of the bitmap is applied, the number of bitmaps that the UE should read can be reduced, thereby enabling faster UE processing.

[0438] If the bitmap Figure 12-11If the bit value of the bitmap is 0, the bit value 0 can indicate performing switching or activation to a dormant bandwidth part for each activated SCell (if a dormant bandwidth part is configured, or if the SCell is included in the first SCell group or the second SCell group) corresponding to each bit. As another approach, if the bit value of the bitmap is 0, the UE can be instructed by the bit value 0 to perform switching or activation to a dormant bandwidth part if, for each activated SCell corresponding to the bit, the activated bandwidth part is not a dormant bandwidth part (or is a normal bandwidth part). If no dormant bandwidth part is configured for the activated SCell corresponding to the bit of the bitmap, the UE can ignore (or can not read or apply) the bit value.

[0439] When the bit value of the bitmap is 1, the bit value 1 can indicate performing switching or activation to a normal bandwidth part (e.g., a first active bandwidth part activated from dormancy) for each activated SCell corresponding to the bit. As another approach, when the bit value of the bitmap is 1, the UE can be instructed by the bit value 1 to perform switching or activation to a normal bandwidth part (e.g., a first active bandwidth part activated from dormancy) if, for each activated SCell corresponding to the bit, the current or activated bandwidth part is a dormant bandwidth part (or is not a normal bandwidth part), and otherwise (if, for each activated SCell corresponding to the bit, the current or activated bandwidth part is not a dormant bandwidth part (or is a normal bandwidth part)), the UE can maintain (or continue to use, apply, or activate) the current active bandwidth part as is. As another approach, when the bit value of the bitmap is 1, the UE can be instructed by the bit value 1 to perform switching or activation from a dormant bandwidth part to a normal bandwidth part (e.g., a first active bandwidth part activated from dormancy) for each activated SCell corresponding to the bit, or can be instructed to maintain (or continue to use, apply, or activate) the current active bandwidth part as is. If no dormant bandwidth part is configured for the activated SCell corresponding to the bit of the bitmap, the UE can ignore (or can not read or apply) the bit value.

[0440] After receiving the DCI of the PDCCH in the PCell, the UE can determine whether there is a bitmap including an indication of a bandwidth part of a cell group (or a secondary cell group) or a bandwidth part of a PSCell (or an SCell) of a cell group (or a secondary cell group) or an indication of suspending or resuming a cell group while reading the DCI. If there is a bitmap, for a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) indicated by each bit of the bitmap, according to a bit value, a bandwidth part can be switched or activated or a cell group can be suspended or resumed. For example, if a bit of the bitmap indicates a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) and the bit value is 1 (or 0), the UE can resume or activate the cell group. When a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) indicated by the bit should be switched or activated to a bandwidth part other than a dormant bandwidth part because the bit value is 1 (or 0), or when the cell group should be resumed, the bit value can not be applied (or can be ignored or can not be read) if the cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) has already been resumed. For example, if a bit of the bitmap indicates a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) and the bit value is 0 (or 1), the UE can switch or activate a bandwidth part of a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) to a dormant bandwidth part, or can suspend or deactivate the cell group. When a cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) indicated by the bit should be switched or activated to a dormant bandwidth part because the bit value is 0 (or 1), or the cell group should be resumed, the bit value can not be applied (or can be ignored or can not be read) for an SCell or each SCell belonging to an SCell group if the SCell is active and the activated bandwidth part is a dormant bandwidth part, or the bit value can not be applied (or can be ignored or can not be read) if the cell group (or a secondary cell group) or a PSCell (or an SCell) of a cell group (or a secondary cell group) has already been suspended or deactivated.

[0441] The third embodiment is as described above, in the third embodiment, the third DCI format of the PDCCH proposed in the third embodiment can be used in the activation time interval, and the PCell of the UE is not accompanied by the downlink transmission resource (e.g., PDSCH) or the uplink transmission resource (e.g., PUSCH) of the SPCell. Accordingly, in the third embodiment, the UE can receive the third DCI format of the PDCCH, and can not transmit the ACK or NACK information (e.g., HARQ ACK or NACK) for the indication of the third DCI format.

[0442] When the first embodiment, the second embodiment, or the third embodiment is applied, if the downlink dormant bandwidth part configured for the SCell or the PSCell of the UE is not configured as a default downlink bandwidth part (default DL BWP), the bandwidth part inactivity timer for switching or shifting the dormant bandwidth part to the default bandwidth part can not be used. This is because, if the default bandwidth part is configured as a normal bandwidth part rather than a dormant bandwidth part, when the timer expires, the switching from the dormant bandwidth part to the normal bandwidth part is automatically performed, and thus the battery consumption due to the PDCCH monitoring can occur.

[0443] Figure 13 FIG. 1 is a diagram illustrating a fourth embodiment in which the first embodiment, the second embodiment, or the third embodiment is extended and applied to a UE in an RRC inactive mode according to an embodiment of the disclosure.

[0444] The fourth embodiment proposes that the UE continuously stores the SCell configuration information (e.g., Figure 6 the configuration information described or proposed in the first embodiment, the second embodiment, or the third embodiment) or the configuration information of the PSCell (or SCell) of the cell group (or secondary group), with reference to Figure 6 These configuration information is configured or stored in the RRC connected mode in the first embodiment, the second embodiment, or the third embodiment, and even if the UE shifts to the RRC inactive mode, they are not cleared or discarded. The fourth embodiment further proposes that, when the UE in the RRC inactive mode performs the RRC connection resume, the UE determines whether to discard or clear, maintain and apply, or reconfigure the stored SCell configuration information (e.g., Figure 6configuration information of a PSCell (or an SCell) of a cell group (e.g., a secondary cell group) described or proposed in the disclosure. When the base station transmits an RRCRelease message including an indicator or configuration for transitioning the UE to an RRC inactive mode, the base station can transmit a message including configuration information or an indicator to the UE, the configuration information or the indicator indicating whether to discard or clear (release), maintain and apply, or reconfigure SCell configuration information stored in the RRCRelease message (e.g., Figure 6 configuration information of a PSCell (or an SCell) of a cell group (e.g., a secondary cell group) described or proposed in the disclosure. When the UE moves in the RRC inactive mode and performs an RNA update, the UE can receive and apply configuration information or an indicator indicating whether to discard or clear, maintain and apply, or reconfigure SCell configuration information stored in an RRCRelease message transmitted by the base station to the UE (e.g., Figure 6 configuration information of a PSCell (or an SCell) of a cell group (e.g., a secondary cell group) described or proposed in the disclosure.

[0445] In a fourth embodiment proposed in the disclosure, the base station can allow configuration of a first active bandwidth part of downlink or uplink bandwidth part configuration information of each cell as a dormant bandwidth part in SCell configuration information (e.g., Figure 6 configuration information of a PSCell (or an SCell) of a cell group (e.g., a secondary cell group) described or proposed in the disclosure. When the UE moves in the RRC inactive mode and performs an RNA update, the UE can receive and apply configuration information or an indicator indicating whether to discard or clear, maintain and apply, or reconfigure SCell configuration information stored in an RRCRelease message transmitted by the base station to the UE (e.g.,

[0446] As another method, in the fourth embodiment proposed in the disclosure, the base station can not configure SCell configuration information (e.g., Figure 6The first active bandwidth part configuration of the downlink or uplink bandwidth part configuration information of each cell in the configuration information of the PSCell (or SCell) of the cell group (for example, secondary cell group) described or proposed in the above can be a dormant bandwidth part, and when the UE activates or resumes each SCell, each cell group, or the PSCell of each cell group, the base station can always activate the downlink bandwidth part or the uplink bandwidth part of each SCell, each cell group, or the PSCell of each cell group to the first active bandwidth part, and can implement switching or activation to the dormant bandwidth part according to the first embodiment, the second embodiment, or the third embodiment proposed in the present disclosure, or can implement suspension or resumption of the cell group, thereby reducing battery consumption of the UE.

[0447] The fourth embodiment proposed above can be extended to each SCell configuration information or PSCell configuration information of the master cell group (MCG) or secondary cell group (SCG) of the UE for which dual connectivity has been configured, so as to be applied. That is, when the UE is transferred to the RRC inactive mode, the SCell configuration information or PSCell configuration information of the SCG can also be stored, and when the RRC connection resumption is performed as described above, or when the UE is transferred to the RRC inactive mode, the base station can transmit configuration information or an indicator to the UE, the configuration information or the indicator indicating whether to discard or clear, maintain and apply, or reconfigure the SCell configuration information (for example, Figure 6 the PSCell configuration information (for example, RRCResume or RRCReconfiguration or RRCRelease message) of the MCG or SCG described or proposed in the above.

[0448] Reference Figure 13 While the UE is in the RRC connected mode, the UE 13-01 can perform network connection to the base station 13-02 and transmit or receive data 13-05. If the base station needs to transfer the UE to the RRC inactive mode for some reason, the base station can transmit an RRCRelease message 13-20 to transfer the UE to the RRC inactive mode. The base station can transmit a message including configuration information or an indicator to the UE, the configuration information or the indicator indicating whether to discard or clear, maintain and apply, or reconfigure the SCell configuration information (for example, Figure 6The base station can determine whether to suspend or resume the PSCell (or SCell) configuration information of the secondary cell group (e.g., secondary cell group) or the PCell (or SCell) configuration information of the cell group (e.g., secondary cell group) described or proposed in the message, and can inquire of the secondary cell base station whether to perform suspension or resumption and receive a response in order to determine whether to suspend or resume the PCell (or SCell) configuration information of the secondary cell group or the PCell (or SCell) configuration information of the cell group (e.g., secondary cell group). The base station can configure, via the RRCRelease message, a list of frequencies to be measured by the UE in the RRC idle mode or the RRC inactive mode, frequency measurement configuration information, a frequency measurement period, etc.

[0449] The UE in the RRC inactive mode can receive the paging message 13-25 while moving, and perform RRC connection resumption when uplink data needs to be transmitted or the RAN notification area needs to be updated.

[0450] When the UE needs to establish a connection, the UE performs random access, and when an RRCResumeRequest message 13-30 is transmitted to the base station, the UE operation related to the transmission of the message is as follows.

[0451] 1. When the UE identifies the system information, and the system information indicates transmission of the full UE connection resume identifier (I-RNTI or full resume ID), the UE prepares to transmit a message including the stored full UE connection resume identifier (I-RNTI). If the system information indicates transmission of the truncated UE connection resume identifier (truncated I-RNTI or truncated resume ID), the UE configures the stored full UE connection resume identifier (I-RNTI) to the truncated UE connection resume identifier (truncated resume ID) according to a predetermined scheme, and prepares to transmit a message including the configured truncated UE connection resume identifier.

[0452] 2. The UE recovers the RRC connection configuration information and security context information from the stored UE context.

[0453] 3. The UE updates the new KgNB security corresponding to the master cell group key based on the current KgNB security key, Next Hop (NH) value, and NCC value received via the RRCRelease message, so as to be stored.

[0454] 4. If the UE receives the SCG counter value (or sk-counter) via the RRCRelease message, the UE updates the new SKgNB security key corresponding to the secondary cell group based on the KgNB security key and the SCG counter (or sk-counter).

[0455] 5. The UE derives new security keys (K_RRCenc, K_RRC_int, K_UPint, and K_UPenc) to be used in integrity protection and verification and encryption and decryption by using the newly updated KgNB security key.

[0456] 6. If the UE receives the SCG counter value (or sk-counter) via the RRCRelease message, the UE derives new security keys (SK_RRCenc, SK_RRC_int, SK_UPint, and SK_UPenc) to be used in integrity protection and verification and encryption and decryption by using the newly updated SKgNB security key.

[0457] 7. The UE calculates the MAC-I and prepares to send a message including the calculated MAC-I

[0458] 8. The UE resumes SRB1 (SRB1 should be resumed in advance because the RRCResume message will be received via SRB1 in response to the RRCResumeRequest message to be sent).

[0459] 9. The UE configures the RRCResumeRequest message and sends the message to the lower layer.

[0460] 10. The UE resumes integrity protection and verification by applying the updated security key and the preconfigured algorithm for all bearers (MCG terminated RBs) except for SRBO corresponding to the master cell group, and applies integrity verification and protection to data to be transmitted and received later (the resumption and application of integrity verification and protection are to increase the reliability and security of data to be transmitted to or received from SRB1 or DRB later).

[0461] 11. The UE resumes encryption and decryption by applying the updated security key and the preconfigured algorithm for all bearers (MCG terminated RBs) except for SRBO corresponding to the master cell group, and applies encryption and decryption to data to be transmitted and received later (the resumption and application of encryption and decryption are to increase the reliability and security of data to be transmitted to or received from SRB1 or DRB later).

[0462] 12. If the UE receives the SCG counter value (or sk-counter) via the RRCRelease message, the UE resumes the integrity protection and verification by applying the updated security key and preconfigured algorithm for all bearers except SRB0 corresponding to the primary cell group (MCG terminated RBs) and applies the integrity verification and protection to data to be transmitted and received later. (The resume and application of the integrity verification and protection are to increase the reliability and security of data to be transmitted to or received from the DRB later.)

[0463] 13. If the UE receives the SCG counter value (or sk-counter) via the RRCRelease message, the UE resumes the encryption and decryption by applying the updated security key and preconfigured algorithm for all bearers except SRB0 corresponding to the secondary cell group (SCG terminated RBs) and applies the encryption and decryption to data to be transmitted and received later. (The resume and application of the encryption and decryption are to increase the reliability and security of data to be transmitted to or received from the DRB later.)

[0464] When the UE needs to establish a connection in order to perform random access, the UE transmits an RRCResumeRequest message to the base station and then receives an RRCResume message 13-35 in response thereto, and the UE proposed to operate as follows. If the RRCResume message includes an indicator indicating (in the case where the UE has valid frequency measurement results measured in the RRC inactive mode) reporting of the frequency measurement results, the UE can report the frequency measurement results configured in the RRCResumeComplete message. The base station can transmit an RRC message (e.g., RRCResume message) including configuration information or an indicator to the UE, the configuration information or the indicator indicating whether to discard or clear, maintain and apply, or reconfigure the SCell configuration information (e.g., configuration information described or proposed in Figure 6

[0465] 1. When receiving the message, the UE recovers the PDCP state corresponding to the primary cell group, resets the COUNT value, and rebuilds the PDCP layer of all DRBs (MCG terminated RBs) and SRB2 corresponding to the primary cell group.

[0466] ​2. If the UE receives the SCG counter value (or sk-counter) via the message, the UE updates a new SKgNB security key corresponding to the secondary cell group based on the KgNB security key and the SCG counter (or sk-counter). The UE derives new security keys (SK_RRCenc, SK_RRC_int, SK_UPint, and SK_UPenc) to be used in integrity protection and verification and encryption and decryption by using the newly updated SKgNB security key corresponding to the secondary cell group.

[0467] 3. If the message includes master cell group (masterCellGroup) configuration information,

[0468] A. The UE performs and applies the master cell group configuration information included in the message. The master cell group information can include configuration information about the RLC layer belonging to the master cell group, a logical channel identifier, a bearer identifier, etc.

[0469] 4. If the message includes bearer configuration information (radioBearerConfig),

[0470] A. The UE performs and applies the bearer configuration information (radioBearerConfig) included in the message. The bearer configuration information (radioBearerConfig) can include configuration information about the PDCP layer of the corresponding bearer, configuration information about the service data adaptation protocol (SDAP) layer, a logical channel identifier, a bearer identifier, etc.

[0471] 5. If the message includes secondary cell group (secondaryCellGroup) configuration information,

[0472] A. The UE performs and applies the secondary cell group configuration information included in the message. The secondary cell group information can include configuration information about the RLC layer belonging to the secondary cell group, a logical channel identifier, a bearer identifier, etc.

[0473] 6. If the message includes secondary bearer configuration information (radioBearerConfig),

[0474] A. The UE performs and applies the secondary bearer configuration information (radioBearerConfig) included in the message. The secondary bearer configuration information (radioBearerConfig) can include configuration information about the PDCP layer of the corresponding secondary bearer, configuration information about the SDAP layer, a logical channel identifier, a bearer identifier, etc.

[0475] 7. The UE restores all DRBs (MCG-terminated RBs) and SRB2 corresponding to the master cell group.

[0476] 8. If the message includes frequency measurement configuration information (measConfig),

[0477] A. The UE performs and applies the frequency measurement configuration information included in the message. That is, frequency measurement can be performed according to the configuration.

[0478] 9. The UE is transferred to the RRC connected mode.

[0479] 10. The UE indicates to the upper layer that the suspended RRC connection has been resumed.

[0480] 11. The UE configures and delivers the RRCResumeComplete message 13-40 for transmission to the lower layer.

[0481] If the UE has the UE context information and the bearer configuration information for the suspended secondary cell group, the UE can perform frequency measurement based on the frequency configuration information configured via system information, the RRCRelease message, or the RRCResume message, and if there is a valid result, the UE can transmit the RRCResumeComplete message including an indicator in order to indicate the presence of the result. When the base station receives the indicator, if it is necessary to resume frequency carrier aggregation or dual connectivity, the base station can indicate to the UE to report the frequency measurement result and receive the frequency measurement result report in the measurement report command 13-45, or the base station can receive the frequency measurement result report 13-50 via the RRCResumeComplete message. When the frequency measurement result is received, the base station can inquire of the secondary cell base station whether to resume the bearer information for the suspended secondary cell group, and can receive a response in order to make a determination, and the base station can provide an indication of the resumption or release of the bearer of the secondary cell group by transmitting the RRCReconfiguration message 13-60 to the UE, and initiate data transfer 13-65. The base station can transmit an RRC message (e.g., RRCReconfiguration message) including configuration information or an indicator to the UE, which indicates whether to discard or clear, maintain and apply, or reconfigure the SCell configuration information (e.g., configuration information described or proposed in Figure 6 ).

[0482] -1> If the UE can be configured with configuration information of only one cell group (e.g., a secondary cell group) (e.g., if the UE can have primary cell group configuration information and configuration information of one secondary cell group), the UE can apply the cell group configuration information according to the indicator of the RRCResume message or can apply dual connectivity as follows.

[0483] ■2> If the RRCResume message includes new cell group (e.g., secondary cell group) configuration information without an indicator for restoring a cell group, the UE can release stored cell group (e.g., secondary cell group) configuration information, can apply the cell group configuration information included in the RRCResume message, and can use dual connectivity.

[0484] ■2> If the RRCResume message includes an indicator for restoring a cell group and new cell group (e.g., secondary cell group) configuration information, the UE can restore stored cell group (e.g., secondary cell group) configuration information, can add the cell group configuration information included in the RRCResume message to the existing cell group configuration information or reconfigure the cell group configuration information to the existing cell group configuration information (delta configuration), and can use dual connectivity based on the added or reconfigured cell group configuration information. If the RRCResume message includes an indicator for restoring a cell group and new cell group (e.g., secondary cell group) configuration information but the new cell group configuration information does not include configuration information for a bearer or a protocol layer, the UE can restore stored cell group (e.g., secondary cell group) configuration information and can use dual connectivity based on the restored cell group configuration information.

[0485] -1> If the UE can be configured with configuration information for multiple cell groups (e.g., secondary cell groups) (e.g., if the UE can have master cell group configuration information and configuration information for multiple secondary cell groups), the UE can apply the cell group configuration information and can apply dual connectivity according to the indicator of the RRCResume message as follows.

[0486] ■2> If the RRCResume message includes new cell group (e.g., secondary cell group) configuration information without an indicator for restoring a cell group, the UE can clear all stored cell group (e.g., secondary cell group) configuration information, can apply the cell group configuration information included in the RRCResume message, and can use dual connectivity. As another method, an indicator, a list, or a cell group identifier for clearing a cell group can be introduced from an RRC message in order to indicate which cell group configuration information among stored cell group configuration information is to be cleared or restored.

[0487] ■2> If the RRCResume message includes an indicator for restoring a cell group and new cell group (e.g., secondary cell group) configuration information, or includes cell group identifier information or cell group state information to be restored (or to be applied, activated, or resumed), the UE can restore the above-indicated cell group configuration information among the stored cell group (e.g., secondary cell group) configuration information, can add the cell group configuration information included in the RRCResume message to the existing cell group configuration information, or reconfigure the cell group configuration information to the existing cell group configuration information (incremental configuration), and can use dual connectivity based on the added or reconfigured cell group configuration information. When the RRCResume message includes an indicator for restoring a cell group and new cell group (e.g., secondary cell group) configuration information, if the RRCResume message includes cell group identifier information or cell group state information to be restored (or to be applied, activated, or resumed), or if the new cell group configuration information does not have configuration information for a bearer or a protocol layer, the UE can restore the above-indicated cell group configuration information among the stored cell group (e.g., secondary cell group) configuration information, and can use dual connectivity based on the restored cell group configuration information.

[0488] In accordance with the present disclosure, Figure 13 In the SCell configuration information (e.g., sCellToReleaseList, sCellToAddModList, or sCellDeactivation) of an RRC message (e.g., RRCRelease, RRCResume, or RRCReconfiguration message), Figure 6In the SCell configuration information or the PSCell (or SCell) configuration information of the cell group (e.g., secondary cell group) described or proposed in the present disclosure, the base station can allow the first active bandwidth part of the downlink or uplink bandwidth part configuration information of each cell to be configured as a dormant bandwidth part, and thus, when the UE activates each SCell or PSCell of the cell group (e.g., secondary cell group), the base station can directly implement the operation of the downlink bandwidth part or uplink bandwidth part of each SCell or PSCell as a dormant bandwidth part, or can implement the suspension or resumption of the cell group, thereby reducing the battery consumption of the UE. For example, one method can be operated for each SCell or PSCell, in which, if the SCell state is configured as active in the SCell configuration information or the cell group configuration information of the RRC message (e.g., RRCRelease, RRCResume, or RRCReconfiguration message), or the cell group state is configured as active, suspended, or deactivated, if an indicator for suspending or resuming the cell group is configured, or if an indication of activating the SCell is received via the MAC control information proposed in the present disclosure, the SCell or PSCell can be activated, resumed, or suspended, and when the SCell or PSCell is activated, the downlink bandwidth part or uplink bandwidth part of the SCell or PSCell can be directly activated to the dormant bandwidth part, thereby reducing the battery consumption of the UE.

[0489] As described above, when the UE in the RRC inactive mode is transferred to the RRC connected mode, and the SCell configuration information or the PSCell (or SCell) configuration information of the cell group (e.g., secondary cell group) proposed in the present disclosure is restored, applied, or reconfigured, according to the first embodiment, the second embodiment, the third embodiment, or the fourth embodiment proposed in the present disclosure, switching or activation between bandwidth parts or activation or application of the dormant bandwidth part can be performed for each activated SCell or activated PSCell (or SCell) of the cell group. The fourth embodiment can also be extended and applied when performing handover.

[0490] If the UE receives the first embodiment, the second information, the third embodiment, or the fourth embodiment proposed in the present disclosure via the RRC message (e.g., RRCRelease, RRCResume, or RRCReconfiguration message) or the MAC control information, the UE can perform the operation of the first embodiment, the second information, the third embodiment, or the fourth embodiment proposed in the present disclosure. Figure 14When the MAC control information proposed in the present disclosure receives an indication of suspension, resumption, activation, or deactivation of a cell group or a PSCell of a cell group, the PHY layer or the MAC layer that has received the indication can indicate the indication to an upper layer (e.g., a MAC layer, an RLC layer, a PDCP layer, or an RRC layer). When the upper layer receives the indication (e.g., cell group suspension, resumption, activation, or deactivation) from the lower layer, a protocol layer procedure for cell group suspension, resumption, activation, or deactivation corresponding to the indication can be performed. Alternatively, if the UE receives an indicator for suspension, resumption, activation, or deactivation of a cell group or a PSCell of a cell group via an RRC message as in the fourth embodiment, the RRC layer that has received the indication can indicate the indication to a lower layer (e.g., a PHY layer, a MAC layer, an RLC layer, or a PDCP layer). When the lower layer receives the indication (e.g., cell group suspension, resumption, activation, or deactivation) from the upper layer, a protocol layer procedure for cell group suspension, resumption, activation, or deactivation corresponding to the indication can be performed.

[0491] By combining or expanding the first embodiment, the second embodiment, the third embodiment, or the fourth embodiment proposed in the present disclosure, various embodiments can be configured and operated.

[0492] Figure 14 FIG. 14 is a diagram illustrating a media access control (MAC) control information (MAC control element, MAC CE) indicating a state transition to an active state, a dormant state, or a deactivated state according to an embodiment of the present disclosure.

[0493] As one embodiment, the activation and deactivation MAC CEs proposed in the present disclosure can have a structure referring to Figure 14 and can be divided into a 1-byte size MAC CE structure 14-05 supporting 7 SCells and a 4-byte size MAC CE structure 14-10 supporting 31 SCells. The activation and deactivation MAC CEs have the following characteristics.

[0494] - When no dormant MAC CE is received and only active and deactivated MAC CEs are received, the UE operates as follows.

[0495] ■ Activating and Deactivating MAC CE: Each field indicates a SCell identifier, and the value corresponding to each field indicates whether the SCell is activated or deactivated. If the indicator value of the SCell indicated by the SCell identifier is 1, the SCell is activated when it is deactivated. However, if the SCell's state is not deactivated, the indicator value is ignored. If the indicator value of the SCell indicated by the SCell identifier is 0, the SCell is deactivated. That is, regardless of the SCell's state, if the SCell's indicator value is 0, the SCell is deactivated.

[0496] New MAC CEs can be designed, or existing MAC CE functionality can be extended to support the embodiments of this disclosure, and extended to various embodiments.

[0497] For example, it can be applied Figure 14 The MAC CE proposed and described in [the document] can be extended... Figure 14 The reserved bits (R bits) in 14-05 or 14-10 are used to expand and apply the present disclosure. Figure 14 The functions described in the document.

[0498] - For example, when the reserved bit (e.g., the R field) is configured to 0 (or 1), a 1-bit indicator (e.g., the C field) indicating the identifier for each SCell can be defined and used as follows. Alternatively, when the reserved bit (e.g., the R field) is configured to 0 (or 1), this can indicate the deactivation or suspension of a cell group (e.g., a secondary cell group). For example, a cell, bandwidth segment, or cell group that has been deactivated or suspended can be moved to a deactivated state or remain unchanged, and a cell, bandwidth segment, or cell group that has been active (or restored) can be moved to a deactivated state. The indication of the identifier can be executed to higher layers.

[0499] ■ If the 1-bit indicator is configured to 0 (or 1), the state transition for each cell (e.g., SCell, or SCell of the primary or secondary cell group) or bandwidth portion can be performed as follows.

[0500] ◆ Cells or bandwidth that have been deactivated are either transferred to a deactivated state or remain unchanged.

[0501] ◆The cell or bandwidth that was already active has been moved to a disabled state.

[0502] ■ If the 1-bit indicator is configured to 1, the state transition for each cell (e.g., SCell, or SCell of the primary or secondary cell group) or bandwidth portion can be performed as follows.

[0503] ◆ A cell or bandwidth part that has been deactivated is transferred to the active state.

[0504] ◆ A cell or bandwidth part that has been deactivated is transferred to the active state.

[0505] - When a reserved bit (R bit) is configured as 1 (or 0), a 1-bit indicator indicating an identifier of each cell (SCell) can be defined and used as follows. As another method, a new logical identifier can be defined, a new MAC CE can be defined, and the new logical identifier and the new MAC CE can be defined and used as follows. As another method, when a reserved bit (e.g., R field) is configured as 1 (or 0), this can indicate an indication of activation or resumption of a cell group (e.g., a secondary cell group). For example, a cell, a bandwidth part, or a cell group that has been activated or resumed can be transferred to the active state or remain unchanged, and a cell, a bandwidth part, or a cell group that has been deactivated (or suspended) can be transferred to the active state. An indication of an identifier can be performed to an upper layer.

[0506] ■ If a 1-bit indicator is configured as 0 (or 1), state transitions of each cell (e.g., SCell, or SCell of a primary cell group or a secondary cell group) or bandwidth part can be performed as follows.

[0507] ◆ A cell or bandwidth part that has been deactivated is transferred to or remains in the deactivated state.

[0508] ◆ A cell or bandwidth part that has been activated is transferred to the deactivated state.

[0509] ■ If a 1-bit indicator is configured as 1, state transitions of each cell (e.g., SCell, or SCell of a primary cell group or a secondary cell group) or bandwidth part can be performed as follows.

[0510] ◆ A cell or bandwidth part that has been activated is transferred to or remains in the active state.

[0511] ◆ A cell or bandwidth part that has been deactivated is transferred to the active state.

[0512] The MAC CE functions described as examples above can be variously extended and designed to indicate state transitions or switching of cells or bandwidth parts so as to be applied to the above-described embodiments. For example, a new MAC control information can be designed, and the MAC control information can include a cell group identifier, a cell identifier, a bandwidth part identifier, or bitmap information, and thus activation (or resumption), dormancy (or suspension), or deactivation (or suspension) of a cell group, a cell, or a bandwidth part can be indicated.

[0513] Hereinafter, the disclosure proposes a procedure of reporting a power headroom.

[0514] In the disclosure, a first embodiment of reporting a power headroom is as follows.

[0515] In the first embodiment, the power headroom report can be used to provide the following information to a base station (serving gNB) serving the UE. The power headroom can indicate a difference between a maximum transmission power (or a calculated or nominal maximum transmission power (nominal UE maximum transmission power)) that the UE can perform transmission in each activated serving cell (PCell, SCell, PSCell, or SPCell) and a power measured for uplink data transmission (UL-SCH) or sounding reference signal (SRS) transmission, or can indicate a difference between the maximum transmission power that the UE can perform transmission and a power measured for uplink data transmission and PUCCH transmission in the SPCell (PCell or PSCell) of another MAC layer (e.g., LTE MAC or E-UTRA MAC). According to the power headroom report, a power headroom value can be configured in MAC control information, and the MAC control information is transmitted via an uplink transmission resource, so that the power headroom can be reported to the base station.

[0516] - The first type of power headroom corresponds to a difference between a maximum transmission power (or a calculated or nominal maximum transmission power (nominal UE maximum transmission power)) that the UE can perform transmission in each activated serving cell (PCell, SCell, PSCell, or SPCell) and a power measured for uplink data transmission (UL-SCH), and can be reported.

[0517] - The second type of power headroom corresponds to a difference between a maximum transmission power (or a calculated or nominal maximum transmission power (nominal UE maximum transmission power)) that the UE can perform transmission and a power measured for uplink data transmission (UL-SCH) or PUCCH transmission in the SPCell (PCell or PSCell) of another MAC layer (e.g., LTE MAC or E-UTRA MAC) and can be reported.

[0518] - The third type of power headroom corresponds to a difference between a maximum transmission power (or a calculated or nominal maximum transmission power (nominal UE maximum transmission power)) that the UE can perform transmission in each activated serving cell (PCell, SCell, PSCell, or SPCell) and a power measured for sounding reference signal (SRS) transmission, and can be reported.

[0519] The UE can be configured with configuration information for power headroom reporting via an RRC message (e.g., RRCReconfiguration), and the RRC layer can adjust the power headroom reporting by using the following parameters.

[0520] - a timer value for periodic power headroom reporting (phr-PeriodicTimer): For example, when the periodic power headroom reporting timer expires, the power headroom reporting can be triggered.

[0521] - a timer value for constraining power headroom reporting (phr-ProhibitTimer): For example, when the power headroom reporting prohibit timer is running, the power headroom reporting is not triggered.

[0522] - a threshold for triggering power headroom reporting (phr-Tx-PowerFactorChange)

[0523] - an indicator indicating the reporting of a second type of power headroom considering another cell or MAC layer (phr-Type2OtherCell)

[0524] - an indicator indicating the reporting of power headroom considering another group of cells (phr-ModeOtherCG)

[0525] - an indicator indicating the reporting of multiple power headrooms (multiplePHR)

[0526] These parameters can be configured via an RRC message (e.g., RRCReconfiguration message), as shown in the disclosure of Figure 6 .

[0527] The power headroom reporting can be triggered when one of the following conditions occurs or is satisfied.

[0528] - If the power headroom reporting prohibit timer (phr-ProhibitTimer) expires or has expired, and if the change in path loss reaches a threshold (phr-Tx-PowerFactorChange) dB, the power headroom reporting is triggered, which is configured via an RRC message for at least one activated serving cell of a certain MAC layer. When the MAC layer has (or receives) an uplink transmission resource for a new transmission after the last transmitted power headroom in the MAC layer, the path loss can be used as a path loss reference value.

[0529] - When the periodic power headroom reporting timer expires, the power headroom reporting can be triggered.

[0530] - A power headroom report can be triggered when a power headroom reporting function is configured or reconfigured by a higher layer (e.g., RRC layer).

[0531] - A power headroom report can be triggered when a cell for which a certain MAC layer's uplink is configured is activated.

[0532] - A power headroom report can be triggered when a PSCell is added, newly added, or changed (or when dual connectivity is configured, and a PSCell of an SCG is newly added or changed).

[0533] - If a power headroom restriction timer (phr-ProhibitTimer) expires or has expired, if the MAC layer has (or receives) an uplink transmission resource for a new transmission, and if the following condition for a serving cell for which a certain MAC layer's uplink is configured is TRUE or satisfied, a power headroom report can be triggered.

[0534] ■The condition is that, when there is PUCCH information or an uplink transmission resource allocated for a transmission in a cell, and there is a PUCCH transmission or an uplink resource for a transmission in a cell in the MAC layer, a power headroom report can be triggered if a change in required power back-off due to power management of the cell (e.g., to reduce interference from other frequencies or to avoid harm to the human body) after the last transmitted power headroom reaches a threshold value (phr-Tx-PowerFactorChange) dB configured via an RRC message.

[0535] Hereinafter, the disclosure proposes that, if one or more events occur or one or more conditions are satisfied among the conditions proposed above, and a power headroom report is thus triggered, the MAC layer operates as follows.

[0536] If the MAC layer has or receives an uplink transmission resource allocated for a new transmission, the MAC layer operates as follows.

[0537] -1> If the uplink transmission resource is the first uplink transmission resource allocated for a new transmission after the last MAC reset,

[0538] ■2> A periodic power headroom reporting timer for a periodic power headroom report is started.

[0539] -1> If it is determined (or decided) in the power headroom report that a power headroom or a power headroom report has been triggered and not cancelled, and

[0540] -1> if, as a result of logical channel prioritization (LCP) (e.g., allocating uplink transmission resources to data or MAC control information), the above-allocated uplink transmission resources can include MAC control information (MAC CE or MAC control element) for a power headroom report configured to be transmitted in a MAC layer and a subheader thereof (e.g., a MAC subheader), or if transmission can be performed via the uplink transmission resources,

[0541] ■2> if an indicator (multiplePHR) indicating a report of multiple power headrooms is configured to be true (or configured to perform a report),

[0542] ◆3> for each activated serving cell connected to or configured in a certain MAC layer and for which uplink is configured,

[0543] ●4> acquire (calculate) a value of a first type power headroom or a third type power headroom of an uplink carrier (or frequency) corresponding to the cell.

[0544] ●4> if, for the serving cell, the MAC layer has or receives an uplink transmission resource allocated for transmission,

[0545] ●4> or if another MAC layer is configured, and the other MAC layer has or receives an uplink transmission resource allocated for transmission with respect to the serving cell, and if an indicator (phr-ModeOtherCG) indicating a power headroom report considering another cell group is configured to be true (Real) (or configured to report an actual value) via an upper layer (RRC layer),

[0546] ■5> acquire a maximum transmission power (or a power value required for power headroom calculation) corresponding to the serving cell from the physical layer.

[0547] ◆3> if an indicator (phr-Type2OtherCell) indicating a report of a second type power headroom considering another cell or MAC layer is configured to be true (or configured to perform a report),

[0548] ●4> if the other MAC layer is an evolved-universal terrestrial radio access (E-UTRA) MAC layer,

[0549] ■5> acquire (or calculate) a value for reporting the second type power headroom with respect to an SPCell of the other MAC.

[0550] ■5> If an indicator (phr-ModeOtherCG) indicating a power headroom report considering another cell group is configured as true (or configured to report an actual value) by the upper layer (RRC layer),

[0551] ◆6> Acquire a maximum transmission power value (or a power value required for power headroom calculation) of the SPCell of another MAC layer (E-UTRA MAC layer) from the physical layer.

[0552] ◆3> Provide an indication to generate and transmit MAC control information for reporting a plurality of power headrooms based on the values reported from the physical layer, to multiplex and reassemble (multiplexing and assembly procedure of the MAC layer).

[0553] ■2> If an indicator (multiplePHR) indicating a report of a plurality of power headrooms is not configured as true (or is not configured to perform a report), if an indicator indicating a report of one power headroom, or if one power headroom report format is used,

[0554] ◆3> Acquire (or calculate) a first type power headroom value of an uplink carrier (or frequency) of a serving cell (or PCell) from the physical layer.

[0555] ◆3> Acquire a maximum transmission power value (or a power value required for power headroom calculation) corresponding to a serving cell (or PCell) from the physical layer.

[0556] ◆3> Provide an indication to generate and transmit MAC control information for reporting one power headroom based on the values reported from the physical layer, to multiplex and reassemble (multiplexing and assembly procedure of the MAC layer).

[0557] ■2> Start or restart a timer for a periodic power headroom report.

[0558] ■2> Start or restart a timer for a constrained power headroom report.

[0559] ■2> Cancel all triggered power headroom reports or power headrooms.

[0560] The power headroom report proposed in the present disclosure makes the UE perform a power headroom report for each cell in order to enable the base station to adjust or manage the uplink transmission power of the UE. However, in the case of a cell (SCell) or a serving cell for which a dormant bandwidth part is configured, or a cell group or a cell that is suspended (or deactivated), if the current or activated bandwidth part (or downlink bandwidth part) of the activated serving cell is a dormant bandwidth part, or if the activation is performed on the bandwidth part indicated by the dormant bandwidth part identifier, even if the power headroom report is performed for the suspended (or deactivated) cell (e.g., PSCell or SCell) of the cell group, uplink data transmission or PUCCH transmission is not possible in the dormant bandwidth part or the suspended (or deactivated) cell group or cell, and thus unnecessary power headroom reporting is performed.

[0561] Therefore, in the following, the present disclosure proposes that, in order to reduce the unnecessary processing load of the UE and prevent the waste of transmission resources due to unnecessary power headroom reporting, the UE first determines whether a cell is activated or deactivated, and for the activated cell, determines whether the activated bandwidth part (e.g., downlink bandwidth part) of the activated cell is a dormant bandwidth part (or a bandwidth part having a dormant bandwidth part identifier configured via an RRC message) or not a dormant bandwidth part (or not a bandwidth part having a dormant bandwidth part identifier configured via an RRC message), or whether a cell group or a cell (e.g., PSCell) is suspended (or deactivated) or activated (or resumed). As another method, the UE can first determine whether a cell is activated or deactivated, and for the activated cell, can determine whether the activated bandwidth part (e.g., downlink bandwidth part) of the activated cell is a dormant bandwidth part (or a bandwidth part having a dormant bandwidth part identifier configured via an RRC message) or not a dormant bandwidth part (or not a bandwidth part having a dormant bandwidth part identifier configured via an RRC message) when the dormant bandwidth part is configured (e.g., if the bandwidth part identifier is configured for the cell via an RRC message). For the activated cell for which the dormant bandwidth part is not configured, the determination of the activated bandwidth part as described above can be omitted (or can not be performed).

[0562] Further, as described above, in the case of a cell (SCell) or a serving cell for which a dormant bandwidth part is configured, if a current or activated bandwidth part (or a downlink bandwidth part) of an activated serving cell is a dormant bandwidth part, or is activated to a bandwidth part indicated by a dormant bandwidth part identifier, or if a cell group or a cell (e.g., a PSCell or an SCell) is suspended (or deactivated), a power headroom report is not triggered, and even if a power headroom report is triggered by another cell, a power headroom is not reported for the suspended (or deactivated) cell. As another method, in the case of a cell (SCell) or a serving cell for which a dormant bandwidth part is configured, only when a current or activated bandwidth part (or a downlink bandwidth part) of an activated serving cell is not a dormant bandwidth part, if an activation is not performed to a bandwidth part indicated by a dormant bandwidth part identifier, or if a cell group or a cell (e.g., a PSCell or an SCell) is not suspended (or if it is activated, resumed, or not deactivated), a power headroom report can be triggered, and even if a power headroom report is triggered by another cell, only when a current or activated bandwidth part (or a downlink bandwidth part) of an activated serving cell is not a dormant bandwidth part as described above, if an activation is not performed to a bandwidth part indicated by a dormant bandwidth part identifier, or if a cell group or a cell (e.g., a PSCell or an SCell) is not suspended (or if it is activated, resumed, or not deactivated), a power headroom can be reported for the activated serving cell. Accordingly, the procedure proposed above enables the UE to reduce unnecessary processing load and prevent waste of transmission resources due to unnecessary power headroom reporting. Specific embodiments of the procedure proposed above will be described in the following second embodiment considering a dormant bandwidth part.

[0563] In the second embodiment considering a dormant bandwidth part in the disclosure, a power headroom report can be used to provide the following information to a base station (serving gNB) serving the UE. The power headroom can indicate a difference between a maximum transmission power (or a calculated or nominal maximum transmission power (nominal UE maximum transmission power)) that the UE can perform transmission in each activated serving cell (PCell, SCell, PSCell, or SPCell) and a power measured for uplink data transmission (UL-SCH) or sounding reference signal (SRS) transmission, or can indicate a difference between a maximum transmission power that the UE can perform transmission and a power measured in an SPCell (PCell or PSCell) of another MAC layer (e.g., LTE MAC or E-UTRA MAC) for uplink data transmission and PUCCH transmission. According to the power headroom report, a power headroom value can be configured in MAC control information, and the MAC control information is transmitted via an uplink transmission resource, so that the power headroom can be reported to the base station.

[0564] - The first type of power headroom corresponds to the difference between the maximum transmission power (or the calculated or nominal maximum transmission power (nominal UE maximum transmission power)) that the UE can perform transmission in each activated serving cell (PCell, SCell, PSCell, or SPCell) and the power measured for uplink data transmission (UL-SCH), and can be reported.

[0565] - The second type of power headroom corresponds to the difference between the maximum transmission power (or the calculated or nominal maximum transmission power (nominal UE maximum transmission power)) that the UE can perform transmission and the power measured in the SPCell (PCell or PSCell) of another MAC layer (e.g., LTE MAC or E-UTRA MAC when dual connectivity is configured) for uplink data transmission (UL-SCH) or PUCCH transmission, and can be reported.

[0566] - The third type of power headroom corresponds to the difference between the maximum transmission power (or the calculated or nominal maximum transmission power (nominal UE maximum transmission power)) that the UE can perform transmission in each activated serving cell (PCell, SCell, PSCell, or SPCell) and the power measured for sounding reference signal (SRS) transmission, and can be reported.

[0567] The second embodiment of the power headroom report considering the dormant bandwidth part is as follows.

[0568] In the second embodiment, the UE can be configured with configuration information for power headroom reporting via an RRC message (e.g., RRCReconfiguration message), and the RRC layer can adjust the power headroom report by using the following parameters.

[0569] - Timer value for periodic power headroom reporting (phr-PeriodicTimer): For example, when the periodic power headroom reporting timer expires, the power headroom report can be triggered.

[0570] - Timer value for constraining power headroom reporting (phr-ProhibitTimer): For example, when the power headroom reporting constraint timer is running, the power headroom report is not triggered.

[0571] - Threshold for triggering power headroom reporting (phr-Tx-PowerFactorChange)

[0572] - Indicator indicating the report of the second type of power headroom considering different cells or MAC layers (phr-Type2OtherCell)

[0573] - an indicator indicating a power headroom report...

Claims

1. A method performed by a terminal in a wireless communication system, the method comprising: The first base station receives a radio resource control (RRC) message including configuration information for a secondary cell group (SCG) comprising at least one serving cell associated with the second base station, wherein the RRC message is used for activating or deactivating the SCG. as well as If the SCG activation is indicated by the RRC message and if the timer associated with the uplink time alignment is not running, a random access procedure is executed for the activation of the SCG.

2. The method according to claim 1, further comprising: If the SCG is deactivated as indicated by the RRC message, a Media Access Control (MAC) reset is performed. as well as Stop at least one timer other than the timer associated with uplink timing alignment.

3. The method according to claim 1, further comprising: If the SCG is deactivated based on the RRC message and uplink data arrives at at least one bearer of the SCG, a first message is sent to the first base station to request the activation of the SCG. as well as Receive a second message from the first base station in response to the first message, for activating the SCG.

4. The method according to claim 1, further comprising: If the SCG activated based on the RRC message is determined to be deactivated, a third message for deactivating the activated SCG is sent to the first base station.

5. A method performed by a first base station in a wireless communication system, the method comprising: Sending a Radio Resource Control (RRC) message to the terminal, which includes configuration information for a secondary cell group (SCG) including at least one serving cell associated with a second base station, wherein the RRC message is used to activate or deactivate the SCG; as well as If the SCG activation is indicated by the RRC message and if the timer associated with the uplink time alignment is not running, the terminal performs a random access procedure for the activation of the SCG.

6. The method according to claim 5, wherein, When the SCG is deactivated as indicated by the RRC message, a Media Access Control (MAC) reset is performed, and At least one timer other than the timer associated with the uplink time alignment is stopped.

7. The method according to claim 5, further comprising: In the event that the SCG is deactivated based on the RRC message and uplink data arrives at at least one bearer of the SCG, the terminal receives a first message requesting the activation of the SCG. as well as Send a second message to the terminal in response to the first message, for the activation of the SCG.

8. The method of claim 5, further comprising: receiving a third message from the terminal for deactivating the activated SCG if the SCG activated based on the RRC message is determined to be deactivated.

9. A terminal in a wireless communication system, the terminal comprising: transceiver; as well as The controller, coupled to the transceiver, is configured to: The system receives a Radio Resource Control (RRC) message from a first base station, comprising configuration information for a secondary cell group (SCG) including at least one serving cell associated with a second base station, wherein the RRC message is used for activating or deactivating the SCG. If the SCG activation is indicated by the RRC message and if the timer associated with the uplink time alignment is not running, a random access procedure is executed for the activation of the SCG.

10. The terminal according to claim 9, wherein, The controller is also configured to: If the SCG is deactivated as indicated by the RRC message, a Media Access Control (MAC) reset is performed, and Stop at least one timer other than the timer associated with uplink timing alignment.

11. The terminal according to claim 9, wherein, The controller is also configured to: If the SCG is deactivated based on the RRC message and uplink data arrives at at least one bearer of the SCG, a first message requesting the activation of the SCG is sent to the first base station. Receive a second message from the first base station in response to the first message, for activating the SCG.

12. The terminal according to claim 9, wherein, The controller is also configured to: If the SCG activated based on the RRC message is determined to be deactivated, a third message for deactivating the activated SCG is sent to the first base station.

13. A first base station in a wireless communication system, the first base station comprising: transceiver; as well as The controller, coupled to the transceiver, is configured to: A radio resource control (RRC) message is sent to the terminal, including configuration information for a secondary cell group (SCG) comprising at least one serving cell associated with a second base station, wherein the RRC message is used for activating or deactivating the SCG. If the SCG activation is indicated by the RRC message and if the timer associated with the uplink time alignment is not running, the terminal performs a random access procedure for the activation of the SCG.

14. The first base station according to claim 13, in, When the SCG is deactivated as indicated by the RRC message, a Media Access Control (MAC) reset is performed, and At least one timer other than the timer associated with the uplink time alignment is stopped.

15. The first base station according to claim 13, wherein, The controller is also configured to: In the case where the SCG is deactivated based on the RRC message and uplink data arrives at at least one bearer of the SCG, the terminal receives a first message requesting the activation of the SCG. Send a second message to the terminal in response to the first message, for the activation of the SCG; as well as If the activated SCG is determined to be deactivated based on the RRC message, a third message for deactivating the activated SCG is received from the terminal.

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