Adaptive control channel monitoring method for terminal low power operation and apparatus thereof

Abstract

A method for monitoring the operation of a terminal in a downlink control channel includes the following steps: receiving configuration information of a first SSSG and a second SSSG from a base station; monitoring the first SSSG during a first time period; and monitoring the second SSSG during a second time period. A DCI (Distributed Control Information Center) may be received from the base station, the DCI including an indication for switching the monitored target from the first SSSG to the second SSSG during a time period prior to the second time period.

Description

Technical Field

[0001] This disclosure relates to a technique for reducing the power consumption of a terminal in a mobile communication system, and more specifically, to a method and apparatus for adaptively monitoring and controlling a control channel to reduce the power consumption of a terminal. Background Technology

[0002] With the development of information and communication technologies, various wireless communication technologies are being developed. Representative wireless communication technologies include Long Term Evolution (LTE) and New Radio (NR), which are defined by the 3rd Generation Partnership Project (3GPP) specifications. LTE can be one of the fourth-generation (4G) wireless communication technologies, and NR can be one of the fifth-generation (5G) wireless communication technologies.

[0003] Communication systems using frequency bands higher than those of Long Term Evolution (LTE) (or LTE-A) communication systems (e.g., 6 GHz or lower) are being considered (e.g., New Radio (NR) communication systems) to handle the surge in wireless data. 5G communication systems can support enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC).

[0004] Therefore, to achieve various communication performance indicators, the processing power of communication nodes has been greatly increased, but this also leads to increased power consumption. Specifically, in the case of terminals, since power is provided by batteries, the rapid power consumption of the terminals may reduce user satisfaction or limit the application areas of the communication system. Therefore, it is necessary to improve the signal transmission methods used to support low-power operation of terminals. Summary of the Invention

[0005] Technical issues

[0006] This disclosure relates to an operational method for a terminal that adaptively monitors the downlink control channel.

[0007] This disclosure relates to providing a configuration for a terminal to adaptively monitor the downlink control channel.

[0008] Technical solutions

[0009] According to an exemplary embodiment of the present disclosure for achieving this purpose, an operational method for a terminal to monitor the Physical Downlink Control Channel (PDCCH) may include: receiving configuration information of a first Search Space Group (SSSG) and a second SSSG from a base station; performing monitoring on the first SSSG during a first time period; and performing monitoring on the second SSSG during a second time period, wherein downlink control information (DCI) including an indication for switching the monitoring target from the first SSSG to the second SSSG is received from the base station during a time period prior to the second time period.

[0010] Each of the first SSSG and the second SSSG may include one or more search space sets to be monitored, and the one or more search space sets may be associated with the same control resource set CORESET or different CORESETs.

[0011] The first SSSG and the second SSSG can be monitored during the same active time of a non-continuous DRX reception cycle.

[0012] The first SSSG can be the starting SSSG for a DRX cycle, and the starting SSSG can be the default SSSG configured by the base station, the SSSG last monitored in a previous DRX cycle of the DRX cycle, or the SSSG that last indicated it would be monitored in a previous DRX cycle.

[0013] The DCI, which includes an indication for switching the monitoring target from the first SSSG to the second SSSG, can be received during the active time of the DRX cycle or during periods outside the active time of the DRX cycle.

[0014] When the DCI is received during the active period of the DRX cycle or during a period outside the active period of the DRX cycle, the DCI may have a DCI format 2_6, and the time for receiving the DCI may be pre-configured between the base station and the terminal.

[0015] Monitoring of the first SSSG and the second SSSG can be performed, regardless of the DRX cycle configured for the terminal.

[0016] The second period can end when the timer initialized when the monitored target switches from the first SSSG to the second SSSG expires, and the timer can be reinitialized if a PDCCH is received through the second SSSG while the timer is running.

[0017] The operation method may further include: receiving information from the base station indicating to skip PDCCH monitoring of the third SSSG during the third time period; and skipping monitoring of the third SSSG during the third time period.

[0018] The third SSSG may include a search space set that indicates skipping PDCCH monitoring, and information about the third SSSG may be defined in the technical specifications or indicated by the base station.

[0019] The first SSSG may have a larger number of PDCCH candidates and / or a shorter PDCCH monitoring period than the second SSSG, and the second SSSG may have a smaller number of PDCCH candidates and / or a longer PDCCH monitoring period than the first SSSG.

[0020] According to another exemplary embodiment of the present disclosure for achieving this purpose, an operational method for a terminal to monitor the physical downlink control channel (PDCCH) may include: obtaining information about a first search space group (SSSG); receiving downlink control information (DCI) from a base station, the DCI including an indication to skip PDCCH monitoring of the first SSSG during a first skip period; and skipping monitoring of the first SSSG during the first skip period.

[0021] The first SSSG may include a search space set that indicates skipping PDCCH monitoring, and information about the first SSSG may be defined in the technical specifications or indicated by the base station.

[0022] A timer can be started when the first skip period begins, and the first skip period can end when the timer expires.

[0023] When the first skip period ends, the operation of monitoring the default SSSG can be performed.

[0024] When the first skip period begins, the timer for the second SSSG used for monitoring before the first skip period can be paused. When the first skip period ends, the timer for the second SSSG can be resumed, and when the first skip period ends, the operation of the second SSSG can be monitored.

[0025] The timer of the third SSSG monitored before entering the first skip period can continue to operate during the first skip period; if the timer of the third SSSG expires when the first skip period ends, the terminal can switch the monitoring target to the default SSSG; and if the timer of the third SSSG does not expire when the first skip period ends, the terminal can perform monitoring on the third SSSG.

[0026] The operation method may further include: obtaining information about the fourth SSSG; receiving from the base station information indicating to skip PDCCH monitoring of the fourth SSSG during a second skip period; and skipping monitoring of the fourth SSSG during the second skip period, wherein the first skip period and the second skip period are different from each other or at least partially overlap.

[0027] According to another exemplary embodiment of this disclosure for achieving this purpose, a terminal for monitoring the Physical Downlink Control Channel (PDCCH) may include: a processor; and a memory storing at least one instruction executable by the processor, wherein the at least one instruction causes the terminal to perform the following operations: receiving configuration information of a first search space set (SSSG), a second SSSG, and a third SSSG from a base station; performing monitoring of the first SSSG during a first time period; performing monitoring of the second SSSG during a second time period; and receiving information from the base station indicating to skip monitoring of the PDCCH of the third SSSG during a third time period, and skipping monitoring of the third SSSG during the third time period.

[0028] Each of the first SSSG and the second SSSG may include one or more search space sets to be monitored, which may be associated with the same control resource set CORESET or different CORESETs. The third SSSG may include one or more search space sets that indicate skipping PDCCH monitoring. Information about the first SSSG may be defined in the technical specifications or indicated by the base station.

[0029] Beneficial effects

[0030] According to exemplary embodiments of the present disclosure, an adaptive downlink control channel (e.g., PDCCH) monitoring method for low-power operation of a terminal can be provided. Therefore, the power consumption of the terminal in a wireless communication system can be reduced. Attached Figure Description

[0031] Figure 1 This is a conceptual diagram illustrating a first exemplary embodiment of the communication system;

[0032] Figure 2 This is a block diagram illustrating a first exemplary embodiment of a communication node constituting a communication system;

[0033] Figure 3a This is a conceptual diagram used to describe an adaptive PDCCH monitoring method according to exemplary embodiments of the present disclosure.

[0034] Figure 3b This is a conceptual diagram used to describe an adaptive PDCCH monitoring method according to another exemplary embodiment of the present disclosure.

[0035] Figure 4 This is a conceptual diagram illustrating a PDCCH monitoring skipping method according to an exemplary embodiment of the present disclosure.

[0036] Figure 5 This is a conceptual diagram illustrating a PDCCH monitoring skipping method according to another exemplary embodiment of the present disclosure.

[0037] Figure 6 This is a conceptual diagram illustrating a method for simultaneously performing PDCCH switching and PDCCH monitoring skipping according to an exemplary embodiment of the present disclosure.

[0038] Figure 7 This is a conceptual diagram illustrating a method for adaptive PDCCH monitoring via downlink DCI indication according to an exemplary embodiment of the present disclosure.

[0039] Figure 8 This is a conceptual diagram illustrating a method for indicative adaptive PDCCH monitoring via downlink DCI according to another exemplary embodiment of the present disclosure. Detailed Implementation

[0040] Because this disclosure can be modified in various ways and has several forms, specific exemplary embodiments will be shown in the accompanying drawings and described in detail in the specific implementation. However, it should be understood that this disclosure is not intended to be limited to the specific exemplary embodiments, but rather, this disclosure will cover all modifications and alternatives that fall within the spirit and scope of this disclosure.

[0041] Relational terms such as "first," "second," etc., may be used to describe various elements, but elements should not be limited by the terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of this disclosure, a first component may be named a second component, and a second component may similarly be named a first component. The term "and / or" means any one or a combination of multiple related and described items.

[0042] When it is said that a component is "coupled" or "connected" to another component, it should be understood that the component is directly "coupled" or "connected" to the other component, or that the other component may be disposed therebetween. Conversely, when it is said that a component is "directly coupled" or "directly connected" to another component, it should be understood that the other component is not disposed therebetween.

[0043] The terminology used in this disclosure is used only to describe particular exemplary embodiments and is not intended to limit the disclosure. Unless the context clearly specifies otherwise, singular expressions include plural expressions. In this disclosure, terms such as “comprising” or “having” are intended to specify the presence of features, quantities, steps, operations, components, parts, or combinations thereof described in the specification; however, it should be understood that these terms do not preclude the presence or addition of one or more features, quantities, steps, operations, components, parts, or combinations thereof.

[0044] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Terms that are commonly used and already in dictionaries shall be interpreted as having a meaning that matches the context in this art. In this specification, unless explicitly defined, terms are not necessarily to be interpreted as having a formal meaning.

[0045] In the following description, the form of this disclosure will be described in detail with reference to the accompanying drawings. In describing this disclosure, for the purpose of a complete understanding, the same reference numerals will refer to the same elements throughout the description of the drawings, and repeated descriptions will be omitted.

[0046] The present invention will describe a wireless communication network applied according to exemplary embodiments of the present disclosure. The wireless communication network applied according to exemplary embodiments of the present disclosure is not limited to what is described below, and exemplary embodiments of the present disclosure can be applied to various wireless communication networks. Here, the term "communication system" may be used in the same sense as "communication network".

[0047] Figure 1 This is a conceptual diagram illustrating a first exemplary embodiment of a communication system.

[0048] Reference Figure 1 The communication system 100 may include multiple communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6. Additionally, the communication system 100 may include a core network (e.g., a Serving Gateway (S-GW), a Packet Data Network (PDN) Gateway (P-GW), and a Mobility Management Entity (MME)). When the communication system 100 is a 5G communication system (e.g., a New Radio (NR) system), the core network may include Access and Mobility Management Functions (AMF), User Plane Functions (UPF), Session Management Functions (SMF), etc.

[0049] Multiple communication nodes 110 to 130 can support communication protocols defined in the 3rd Generation Partnership Project (3GPP) technical specifications (e.g., LTE communication protocol, LTE-A communication protocol, NR communication protocol, etc.). Multiple communication nodes 110 to 130 can support communication protocols based on Code Division Multiple Access (CDMA), Wideband CDMA (WCDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiplexing (OFDM), Filtered OFDM, Cyclic Prefix OFDM (CP-OFDM), Discrete Fourier Transform Extended OFDM (DFT-s-OFDM), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier FDMA (SC-FDMA), Non-Orthogonal Multiple Access (NOMA), Generalized Frequency Division Multiplexing (GFDM), Filter Bank Multicarrier (FBMC), Universal Filtered Multicarrier (UFMC), and Space Division Multiple Access (SDMA), etc. Each of the multiple communication nodes can have the following structure.

[0050] Figure 2 This is a block diagram illustrating a first exemplary embodiment of a communication node constituting a communication system.

[0051] Reference Figure 2 The communication node 200 may include at least one processor 210, a memory 220, and a transceiver 230 connected to a network for performing communication. Furthermore, the communication node 200 may also include an input interface device 240, an output interface device 250, a storage device 260, etc. Each component included in the communication node 200 can communicate with each other when connected via a bus 270.

[0052] However, each component included in communication node 200 may be connected to processor 210 via a separate interface or a separate bus instead of via the common bus 270. For example, processor 210 may be connected to at least one of memory 220, transceiver 230, input interface device 240, output interface device 250, and storage device 260 via one or more dedicated interfaces.

[0053] Processor 210 can execute a program stored in at least one of memory 220 and storage device 260. Processor 210 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor that executes methods according to embodiments of the present disclosure thereon. Each of memory 220 and storage device 260 may be constituted by at least one of volatile storage medium and non-volatile storage medium. For example, memory 220 may include at least one of read-only memory (ROM) and random access memory (RAM).

[0054] This disclosure relates to a method for transmitting and receiving signals in a communication system, and more specifically, to a method for transmitting a downlink control channel to reduce power consumption of a terminal in a wireless communication system. The exemplary embodiments described below can be applied not only to NR communication systems but also to other communication systems (e.g., LTE communication systems, 5G communication systems, sixth-generation (6G) communication systems, etc.).

[0055] NR communication systems can support wider system bandwidths (e.g., carrier bandwidth) than those provided by LTE communication systems, enabling efficient use of wideband frequencies. For example, the maximum system bandwidth supported by an LTE communication system can be 20 MHz. On the other hand, NR communication systems can support carrier bandwidths of up to 100 MHz in frequency bands of 6 GHz or lower, and up to 400 MHz in frequency bands of 6 GHz or higher.

[0056] The parameter set (numerology) of physical signals and channels applied in a communication system (e.g., an NR communication system) can be variable. The parameter set can vary to meet various technical requirements of the communication system. In a communication system applying OFDM waveform technology based on cyclic prefix (CP), the parameter set may include subcarrier spacing and CP length (or CP type). Table 1 below may be a first exemplary embodiment of configuring the parameter set for CP-based OFDM. Adjacent subcarrier spacing may have a 2-fold multiplicative relationship, and the CP length may be scaled at the same ratio as the OFDM symbol length. Depending on the frequency band in which the communication system operates, at least some parameter sets in the parameter set of Table 1 may be supported. Additionally, parameter sets not listed in Table 1 may be further supported in the communication system. For a specific subcarrier spacing (e.g., 60 kHz), one or more CP types (e.g., extended CP) not listed in Table 1 may also be supported.

[0057] [Table 1]

[0058]

[0059] The following description describes the frame structure in a communication system. In the time domain, the elements constituting the frame structure may include subframes, time slots, microslots, symbols, etc. Subframes can be used as units for transmission, measurement, etc., and their length may have a fixed value (e.g., 1 ms) regardless of the subcarrier spacing. Time slots may include consecutive symbols (e.g., 14 OFDM symbols). The length of a time slot may vary differently from the length of a subframe. For example, the length of a time slot may be inversely proportional to the subcarrier spacing.

[0060] A time slot can be used as a unit for transmission, measurement, scheduling, resource allocation, timing (e.g., scheduling timing, Hybrid Automatic Repeat Request (HARQ) timing, Channel State Information (CSI) measurement and reporting timing, etc.). The length of the actual time resource used for transmission, measurement, scheduling, resource allocation, etc., may not match the length of the time slot. A microtime slot may comprise consecutive (one or more) symbols, and the length of a microtime slot may be shorter than the length of a time slot. A microtime slot can be used as a unit for transmission, measurement, scheduling, resource allocation, timing, etc. Microtime slots (e.g., microtime slot length, microtime slot boundaries, etc.) may be predefined in the technical specification. Optionally, microtime slots (e.g., microtime slot length, microtime slot boundaries, etc.) may be configured (or indicated) to the terminal. The use of microtime slots may be configured (or indicated) to the terminal when certain conditions are met.

[0061] A base station can use some or all of the symbols constituting a time slot to schedule a data channel (e.g., Physical Downlink Shared Channel (PDSCH), Physical Uplink Shared Channel (PUSCH), Physical Sidelink Shared Channel (PSSCH)). Specifically, for URLLC transmissions, unlicensed band transmissions, transmissions in the coexistence of NR and LTE communication systems, and multi-user scheduling based on analog beamforming, a portion of the time slot can be used to transmit the data channel. Additionally, a base station can use multiple time slots to schedule the data channel. Furthermore, a base station can use at least one micro-time slot to schedule the data channel.

[0062] In the frequency domain, elements constituting a frame structure may include resource blocks (RBs), subcarriers, etc. An RB may include consecutive subcarriers (e.g., 12 subcarriers). The number of subcarriers constituting an RB can be constant, regardless of the parameter set. In this case, the bandwidth occupied by an RB may be proportional to the subcarrier spacing of the parameter set. RBs can be used as units for transmission and resource allocation in data channels, control channels, etc. Resource allocation for data channels can be performed in units of RBs or RB groups (e.g., resource block groups (RBGs)). An RBG may include one or more consecutive RBs. Resource allocation for control channels can be performed in units of control channel elements (CCEs). A CCE in the frequency domain may include one or more RBs.

[0063] In NR communication systems, time slots (e.g., time slot formats) may include one or more combinations of downlink time slots, flexible time slots (or unknown time slots), and uplink time slots. Each of the downlink time slot, flexible time slot, and uplink time slot may include one or more consecutive symbols. Flexible time slots may be located between downlink and uplink time slots, between a first downlink and a second downlink time slot, or between a first uplink and a second uplink time slot. When a flexible time slot is inserted between downlink and uplink time slots, the flexible time slot can be used as a guard period.

[0064] A time slot may include one or more flexible time periods. Optionally, a time slot may not include flexible time periods. The terminal may perform predefined operations within flexible time periods. Optionally, the terminal may perform operations configured semi-statically or periodically by the base station. For example, operations periodically configured by the base station may include PDCCH monitoring operations, Synchronization Signal / Physical Broadcast Channel (SS / PBCH) block reception and measurement operations, Channel State Information Reference Signal (CSI-RS) reception and measurement operations, Downlink Semi-Persistent Scheduling (SPS) PDSCH reception operations, Probe Reference Signal (SRS) transmission operations, Physical Random Access Channel (PRACH) transmission operations, periodically configured PUCCH transmission operations, and PUSCH transmission operations with configured authorization, etc. Flexible symbols may be overridden by downlink symbols or uplink symbols. When a flexible symbol is overridden by a downlink or uplink symbol, the terminal may perform a new operation instead of an existing operation in the corresponding flexible symbol (e.g., the overriding flexible symbol).

[0065] The time slot format can be semi-statically configured by higher-layer signaling (e.g., Radio Resource Control (RRC) signaling). Information indicating the semi-static time slot format can be included in the system information, and the semi-static time slot format can be configured in a cell-specific manner. Additionally, the semi-static time slot format can be further configured for each terminal via terminal-specific higher-layer signaling (e.g., RRC signaling). Flexible symbols for the cell-specific configured time slot format can be overridden by downlink or uplink symbols via terminal-specific higher-layer signaling. Furthermore, the time slot format can be dynamically indicated by physical layer signaling (e.g., Time Slot Format Indicator (SFI) included in the Downlink Control Information (DCI)). The semi-statically configured time slot format can be overridden by the dynamically indicated time slot format. For example, semi-static flexible symbols can be overridden by downlink or uplink symbols via the SFI.

[0066] Base stations and terminals can perform downlink, uplink, and sidelink operations within a bandwidth portion. A bandwidth portion can be defined as a set of consecutive redundancies (RBs) (e.g., physical resource blocks (PRBs)) with a specific set of parameters in the frequency domain. RBs constituting a bandwidth portion can be consecutive in the frequency domain. A set of parameters can be used to transmit signals (e.g., transmission control channels or data channels) within a bandwidth portion. In an exemplary embodiment, "signal" can refer to any physical signal and channel when used broadly. A terminal performing an initial access procedure can obtain configuration information for the initial bandwidth portion from the base station via system information. A terminal operating in RRC connection state can obtain configuration information for the bandwidth portion from the base station via terminal-specific higher-layer signaling.

[0067] The configuration information for the bandwidth portion may include a set of parameters applied to the bandwidth portion (e.g., subcarrier spacing and CP length). Furthermore, the configuration information for the bandwidth portion may also include information indicating the location of the starting RB (e.g., the starting PRB) of the bandwidth portion and information indicating the number of RBs (e.g., PRBs) constituting the bandwidth portion. At least one of the bandwidth portions (one or more) configured in the terminal can be activated. For example, within a carrier, an uplink bandwidth portion and a downlink bandwidth portion can be activated separately. In a time-division duplex (TDD) based communication system, a pair of uplink and downlink bandwidth portions can be activated. The base station can configure multiple bandwidth portions for the terminal within a carrier and can switch the effective bandwidth portion of the terminal.

[0068] In an exemplary embodiment, activating a frequency band (e.g., carrier, bandwidth portion, RB set, listen-before-speak (LBT) subband, guard band, etc.) may mean a state in which a base station or terminal can transmit and receive signals using that frequency band. Additionally, activating a frequency band may mean that a transceiver's radio frequency (RF) filter (e.g., a bandpass filter) operates when that frequency band is included.

[0069] In an exemplary embodiment, RB may refer to a common RB (CRB). Alternatively, RB may refer to a PRB or a virtual RB (VRB). In an NR communication system, CRB may refer to an RB that forms a set of consecutive RBs (e.g., a common RB grid) based on a reference frequency (e.g., point A). Carriers, bandwidth portions, etc., may be arranged on the common RB grid. That is, carriers, bandwidth portions, etc., may consist of (one or more) CRBs. The RB or CRB constituting the bandwidth portion may be referred to as a PRB, and the CRB index within the bandwidth portion may be appropriately converted to a PRB index. In an exemplary embodiment, RB may refer to an interleaved RB (IRB).

[0070] The smallest resource unit that constitutes a PDCCH can be a group of resource elements (REG). A REG can consist of a PRB (e.g., 12 subcarriers) in the frequency domain and an OFDM symbol in the time domain. Therefore, a REG can include 12 resource elements (REs). The demodulation reference signal (DMRS) used to demodulate the PDCCH can be mapped to 3 of the 12 REs that make up the REG, and control information (e.g., modulated DCI) can be mapped to the remaining 9 REs.

[0071] A PDCCH candidate can consist of a single CCE or an aggregated CCE. A CCE can consist of multiple REGs. NR communication systems support CCE aggregation levels 1, 2, 4, 8, 16, etc., and a CCE can consist of six REGs.

[0072] A control resource set (CORESET) can be a resource region in which a terminal performs blind decoding of a PDCCH. A CORESET can consist of multiple REGs. A CORESET can consist of one or more PRBs in the frequency domain and one or more symbols (e.g., OFDM symbols) in the time domain. The symbols constituting a CORESET can be continuous in the time domain. The PRBs constituting a CORESET can be continuous or discontinuous in the frequency domain. A DCI (e.g., a DCI format or a PDCCH) can be transmitted within a CORESET. Multiple CORESETs can be configured for a cell and a terminal, and multiple CORESETs can overlap in time-frequency resources.

[0073] CORESET can be configured in the terminal via PBCH (e.g., system information sent via PBCH). The identifier (ID) of the CORESET configured by PBCH can be 0. That is, the CORESET configured by PBCH can be referred to as CORESET#0. Terminals operating in RRC idle state can perform monitoring operations in CORESET#0 to receive the first PDCCH during initial access. Not only terminals operating in RRC idle state but also terminals operating in RRC connected state can perform monitoring operations in CORESET#0. CORESET can be configured in the terminal by system information other than system information sent via PBCH (e.g., System Information Block Type 1 (SIB1)). For example, in order to receive a random access response (or Msg2) during random access, the terminal can receive SIB1 including the configuration information of CORESET. In addition, CORESET can be configured in the terminal via terminal-specific higher-layer signaling (e.g., RRC signaling).

[0074] In each downlink bandwidth portion, one or more CORESETs can be configured for the terminal. The terminal can monitor (one or more) PDCCH candidates configured for CORESETs in the corresponding downlink active bandwidth portion. Optionally, the terminal can monitor (one or more) PDCCH candidates configured for CORESETs (e.g., CORESET#0) in downlink bandwidth portions other than the downlink active bandwidth portion. The initial downlink active bandwidth portion may include CORESET#0 and may be associated with CORESET#0. CORESET#0, which has a quasi-co-address (QCL) relationship with the SS / PBCH block, can be configured for terminals in the primary cell (PCell), secondary cell (SCell), and primary-secondary cell (PSCell). In the secondary cell (SCell), CORESET#0 may not be configured for the terminal.

[0075] The search space can be a set of candidate resource regions through which a PDCCH can be sent. The terminal can perform blind decoding on each PDCCH candidate within the predefined search space. The terminal can determine whether a PDCCH has been sent to itself by performing a Cyclic Redundancy Check (CRC) on the result of the blind decoding. When it is determined that the PDCCH is for the terminal itself, the terminal can receive the PDCCH. The terminal can periodically monitor the search space, and can monitor the search space at one or more time locations within a time period (e.g., PDCCH monitoring timing, CORESET).

[0076] PDCCH candidates can be configured using CCEs selected by a predefined hash function at the time of CORESET or search space. A search space can be defined and configured for each CCE aggregation level. In this case, the set of search spaces for all CCE aggregation levels can be referred to as a "search space set". In an exemplary embodiment, "search space" may mean "search space set", and "search space set" may mean "search space".

[0077] A search space set can be logically associated with or correspond to a CORESET. A CORESET can be logically associated with or correspond to one or more search space sets. A common search space set configured via PBCH can be used to monitor the DCI scheduling for sending SIB1 PDSCHs. The ID of a common search space set configured via PBCH can be set to 0. That is, a common search space set configured via PBCH can be defined as a type 0PDCCH common search space set or search space set #0. Search space set #0 can be logically associated with CORESET #0.

[0078] Search space sets can be categorized into common search space sets and terminal-specific (i.e., UE-specific) search space sets based on purpose or related operations. Common DCIs can be transmitted in the common search space set, and UE-specific DCIs can be transmitted in the UE-specific search space set. Considering scheduling flexibility and / or backhaul transmission, UE-specific DCIs can also be transmitted in the common search space set. For example, common DCIs may include resource allocation information for PDSCHs used to transmit system information, paging, power control commands, slot format indicators (SFIs), preemption indicators, etc. UE-specific DCIs may include resource allocation information for PDSCHs and / or PUSCHs, etc. Multiple DCI formats can be defined based on the DCI payload or size, and / or the type of Radio Network Temporary Identifier (RNTI), etc.

[0079] In the exemplary embodiments below, the common search space may be referred to as a CSS, and the set of common search spaces may be referred to as a CSS set. Additionally, in the exemplary embodiments below, the UE-specific search space may be referred to as a USS, and the set of UE-specific search spaces may be referred to as a USS set.

[0080] DRX Operation

[0081] If a terminal constantly monitors the downlink control channel (e.g., PDCCH) regardless of the presence or absence of traffic, it may result in unnecessary power consumption. Therefore, the terminal can perform discontinuous reception (DRX) operation. A terminal performing DRX operation can be activated to monitor the PDCCH during a specific time period and can refrain from PDCCH monitoring during the remaining time periods. The specific time period may be referred to as the active time, and the terminal's operating state during the corresponding time period may be referred to as the DRX enabled state, etc. The time period outside the active time period may be referred to as the DRX period, and the terminal's operating state during the corresponding period may be referred to as the DRX state, DRX disabled state, DRX mode, etc.

[0082] The active time may include the duration of the enable duration timer, the duration of the DRX inactivity timer, etc. The duration of the enable duration timer may be referred to as the "enable duration," etc. The enable duration timer may start at the beginning of each DRX cycle, and the timer's expiration time may be the end time of the enable duration. Additionally, the start time of the enable duration (or active time) may be indicated as a predetermined offset elapsed from the start time of each DRX cycle. The terminal may monitor the PDCCH for a predetermined period determined by the DRX inactivity timer, starting from the time of successful PDCCH reception (e.g., the time slot, subframe, or symbol in which the PDCCH is received). That is, the DRX inactivity timer may be started or reset at the time when the terminal successfully receives the PDCCH (e.g., the time slot, subframe, or symbol). The terminal may consider the time until the DRX inactivity timer expires as the active time and monitor the PDCCH during the active time. The aforementioned timer may be decremented by 1 for each reference time (e.g., the time slot, subframe, or symbol), and each timer may expire at the time when the timer's value becomes 0 (e.g., the time slot, subframe, or symbol).

[0083] When the above timer operations are combined, a terminal in the DRX off state can begin PDCCH monitoring operations by entering the on duration (or active time) at the start time of the DRX cycle or after a predetermined offset from the start time of the DRX cycle. When the terminal successfully receives a PDCCH during the on duration of a DRX cycle, it can start the terminal's DRX inactivity timer, thereby extending the active time. On the other hand, when the terminal fails to receive or does not receive a PDCCH during the on duration of the DRX cycle, the terminal can re-enter the DRX off state at the expiration time of the on duration timer (i.e., the end time of the on duration). Additionally, the terminal can receive a Media Access Control (MAC) element (CE) from the base station and can be instructed to enter the DRX off state. In this case, the terminal can enter DRX mode regardless of the timers in operation and can stop the on duration timer and the DRX inactivity timer.

[0084] DRX operations may include DRX operations based on a long DRX cycle (hereinafter referred to as "long DRX operations") and DRX operations based on a short DRX cycle (hereinafter referred to as "short DRX operations"). Only one of the long DRX operation and the short DRX operation may be performed. Optionally, the long DRX operation and the short DRX operation may be combined and performed. The above operations may be performed for each DRX cycle. The above operations may be applied to terminals in RRC connected mode. Optionally, the above operations may also be applied to terminals in RRC idle mode or RRC inactive mode.

[0085] The following describes adaptive PDCCH monitoring for low-power operation of the terminal. The proposed adaptive PDCCH monitoring method includes a PDCCH switching method and a PDCCH monitoring skipping method. In the following description, the search space set (SSSG) may refer to a set of (one or more) PDCCH search space sets, a set of (one or more) CORESETs, a set of (one or more) PDCCH monitoring opportunities, and / or a set of (one or more) PDCCH candidates.

[0086] PDCCH switching method

[0087] The base station can dynamically change or switch one or more SSSGs monitored by the terminal. To do this, multiple SSSGs (one or more) can be configured or defined in the terminal. For example, the configuration information for each search space set may include the number or ID of one or more SSSGs to which the search space set belongs. Each search space set may be included in one SSSG or may be included in multiple SSSGs. Search space sets belonging to the same SSSG may be associated with the same CORESET or may be associated with different CORESETs.

[0088] Based on this configuration, the base station can instruct (or configure) the terminal to monitor specific (one or more) SSSGs. When the indicated (one or more) SSSGs are different from the currently monitored (one or more) SSSGs, the terminal can perform SSSG handover and can perform monitoring operations on the indicated (one or more) SSSGs. When the indicated (one or more) SSSGs are the same as the currently monitored (one or more) SSSGs, the terminal can maintain the current PDCCH monitoring operation. In the following text, "PDCCH monitoring instruction" may also be referred to as "PDCCH handover instruction," "PDCCH change instruction," "SSSG monitoring instruction," "SSSG handover instruction," "SSSG change instruction," etc.

[0089] SSSG monitoring indication information may be included in the DCI and sent to the terminal or terminal group. The SSSG monitoring indication information may include information about the number or ID of one or more SSSGs, information indicating whether an SSSG handover is being performed (e.g., an SSSG handover flag), etc. For example, SSSG monitoring indication information may be sent to the terminal or terminal group via a group common DCI (e.g., DCI format 2_0, DCI format 2_6). As another example, SSSG monitoring indication information may be sent to the terminal or terminal group via a scheduling DCI (e.g., DCI formats 0_0, 1_0, 0_1, 1_1, 0_2, 1_2, ...).

[0090] According to the SSSG monitoring instruction, the terminal's PDCCH monitoring operation can be changed in units of time slots (or micro-time slots). Even if the instruction dynamically changes (one or more) SSSGs, the terminal can still perform monitoring operations on the same (one or more) SSSGs within a time slot (or micro-time slot). The time for applying each SSSG monitoring instruction (or SSSG handover instruction) can be a specific time slot, the start time of a time slot, the boundary between certain time slots, etc. The time for applying the SSSG monitoring instruction can be determined based on the time when the terminal obtains the SSSG monitoring instruction. For example, the time slot in which the terminal applies the SSSG monitoring instruction can be the first time slot that appears after a predetermined time period (e.g., M symbols (one or more)) from the time the terminal receives the SSSG monitoring instruction (e.g., the last symbol of the DCI including the SSSG monitoring instruction). Here, M can be a natural number and can be predefined in the technical specifications or transmitted to the terminal by a signal from the base station.

[0091] The aforementioned SSSG handover scheme can be used for low-power operation of the terminal. For example, the first SSSG configured in the terminal may have a larger number of PDCCH candidates and / or a shorter PDCCH monitoring period, while the second SSSG configured in the same terminal may have a smaller number of PDCCH candidates and / or a longer PDCCH monitoring period. In this case, if the SSSG monitored by the terminal is switched from the first SSSG to the second SSSG, the terminal's power consumption can be reduced. On the other hand, when the SSSG monitored by the terminal is switched from the second SSSG to the first SSSG, the terminal's power consumption can increase. The base station can appropriately control the set of PDCCHs monitored by the terminal according to service conditions, and therefore, the terminal's power consumption can also be controlled.

[0092] At the same time, the SSSG switching operation can be performed together with the DRX operation.

[0093] Figure 3a This is a conceptual diagram used to describe an adaptive PDCCH monitoring method according to exemplary embodiments of the present disclosure.

[0094] Reference Figure 3a The terminal can perform DRX operations and PDCCH monitoring during the active period. The terminal can dynamically change SSSG monitoring operations during the active period. For example, the terminal can perform an SSSG switching operation between a first SSSG and a second SSSG during the active period. Alternatively, the terminal can skip PDCCH monitoring during certain periods of the active period. This can be achieved through a PDCCH monitoring skipping method, which will be described later. As a result, the terminal's power consumption can be further reduced.

[0095] Alternatively, an SSSG handover operation can be performed without a DRX operation.

[0096] Figure 3b This is a conceptual diagram used to describe an adaptive PDCCH monitoring method according to another exemplary embodiment of the present disclosure.

[0097] Reference Figure 3b The terminal can perform SSSG handover operations between the first SSSG and the second SSSG. Optionally, the terminal can perform PDCCH monitoring skip operations on the first SSSG and / or the second SSSG. The base station can appropriately allocate time periods for SSSG handover, PDCCH monitoring skip, etc. (e.g., low-power mode periods), and can perform operations corresponding to DRX operations according to the configuration. Simultaneously, even during periods of SSSG handover, PDCCH monitoring skip, etc., the terminal can perform operations such as Radio Resource Monitoring (RRM) measurements, CSI measurements and reporting, and system information reception. This differs from conventional DRX operations.

[0098] When a terminal performs both an SSSG handover operation and a DRX operation, the SSSG handover operation can be performed regardless of the DRX on / off state. As a result, the SSSG (hereinafter, "starting SSSG" or "default SSSG") monitored by the terminal at the beginning of a DRX cycle (e.g., one or more time slots including the first time slot of the DRX cycle) may be the same as the SSSG last monitored by the terminal in a previous DRX cycle or the SSSG last instructed to be monitored by the terminal in a previous DRX cycle. According to the above scheme, since the starting SSSG of a DRX cycle is determined by the previously monitored SSSG (or the previously instructed SSSG to be monitored), the base station may have difficulty correctly controlling the starting SSSG for each DRX cycle.

[0099] Therefore, a method could be considered to associate SSSG handover operations with DRX on / off states. SSSG monitoring or handover can be performed based on specific DRX operations. That is, a specific DRX operation can trigger (or indicate) SSSG monitoring or handover. For example, the base station can configure or indicate (one or more) start SSSGs (or default SSSGs) to the terminal.

[0100] One or more initial SSSGs can be configured to the terminal via RRC signaling procedures. The initial SSSGs can be the same for all DRX cycles, or they can be different for each DRX cycle. The terminal can begin monitoring one or more initial SSSGs at the start time of each DRX cycle (or after a predetermined time offset from the start time) (i.e., at the time of transition from DRX off to DRX on). Optionally, the SSSG monitored by the terminal at the end of the active time (i.e., when transitioning from DRX on to DRX off, or when a timer (e.g., an SSSG switching timer) expires after that time) can be designated as (i.e., maintained as or changed to) the initial SSSG, and the initial SSSG can be maintained until the start of the next DRX cycle. In this case, the SSSG monitored (or configured to the terminal) can be maintained even during periods outside the active time. When a previously monitored SSSG differs from the initial SSSG, the terminal can perform a switch to the initial SSSG, and when a previously monitored SSSG is the same as the initial SSSG, monitoring of the initial SSSG can be maintained.

[0101] One or more start SSSGs can be indicated to the terminal via DCI. For example, one or more start SSSGs can be sent to the terminal or terminal group via group common DCI (e.g., DCI format 2_0, DCI format 2_6), scheduling DCI (e.g., DCI formats 0_0, 1_0, 0_1, 1_1, 0_2, 1_2…), etc. The DCI (e.g., DCI format 2_6) including information indicating one or more start SSSGs can be sent during periods outside the active time and before the start time of the next active time. In this case, the DCI (e.g., DCI format 2_6) can further include information about the terminal's wake-up, that is, whether the terminal will transition to the DRX-on state and perform PDCCH monitoring in the next DRX cycle. Optionally, a DCI (e.g., DCI format 2_0, 2_6, 0_0, 1_0, 0_1, 1_1, 0_2, 1_2, ...) including information indicating the start of one or more SSSGs may be sent during the activity period, and may also include information about the start of one or more SSSGs for the next activity period (or the activity period of the next DRX cycle).

[0102] When a terminal is configured to monitor DCI (e.g., DCI format 2_6) but does not receive DCI in a certain DRX cycle, or when the terminal is not configured to monitor DCI (e.g., DCI format 2_6), the terminal may consider (one or more) SSSGs configured through the RRC signaling procedure, (one or more) SSSGs last monitored by the terminal in the previous DRX cycle, or (one or more) SSSGs last instructed to be monitored by the terminal in the previous DRX cycle as (one or more) starting SSSGs of the corresponding DRX cycle. Here, the situation of not receiving DCI may include the terminal failing to successfully receive DCI, the absence of a valid PDCCH monitoring opportunity for receiving DCI, etc. Optionally, when a terminal is configured to monitor a DCI (e.g., DCI format 2_6), but the interval between the start time of a DRX cycle and the timing of one or more PDCCH monitoring for the DCI (e.g., DCI format 2_6) of the corresponding DRX cycle is equal to or less than a reference value, the terminal may consider one or more SSSGs configured through the RRC signaling procedure, one or more SSSGs last monitored by the terminal in a previous DRX cycle, or one or more SSSGs last instructed to be monitored by the terminal in a previous DRX cycle as the starting SSSG of the corresponding DRX cycle. The reference value may be the minimum distance (e.g., one or more symbols) between the time when the DCI (e.g., DCI format 2_6) is received (e.g., the last symbol of the received DCI) and the time when a PDCCH handover is applied (e.g., the first symbol of the time slot for which the PDCCH handover is applied). The reference value may be a time value corresponding to the time spent by the terminal decoding the PDCCH and obtaining the DCI and the time spent by the terminal performing an SSSG handover. Optionally, the terminal may expect the interval between the start time of a certain DRX cycle and at least one PDCCH monitoring timing for the DCI (e.g., DCI format 2_6) for the corresponding DRX cycle to be equal to or greater than a reference value.

[0103] PDCCH monitoring skipping method

[0104] The base station can instruct the terminal to skip PDCCH monitoring. The terminal can receive information instructing to skip PDCCH monitoring (i.e., a PDCCH monitoring skip instruction) via the DCI, and based on this, can refrain from performing PDCCH monitoring operations for a certain period. The location of a certain period (i.e., the period during which the terminal skips PDCCH monitoring (hereinafter, "PDCCH monitoring skip period")) can be configured to the terminal via a separate signaling procedure (e.g., an RRC signaling procedure), or can be indicated to the terminal by being included in the DCI. The configuration or indication information for the PDCCH monitoring skip period may include the end time and / or start time of the PDCCH monitoring skip period, the duration of the PDCCH monitoring skip period, etc. The PDCCH monitoring skip period can be configured as one or more time slots (or one or more symbols, one or more subframes).

[0105] The application of PDCCH monitoring indications (e.g., SSSG handover indications) or PDCCH monitoring skip indications, including one or more search space sets, one or more coresets, one or more PDCCH monitoring timings, and / or one or more PDCCH candidates, can be defined in the technical specifications. For example, when instructed to skip PDCCH monitoring, a terminal can skip PDCCH monitoring of all search space sets (one or more) (or all PDCCH candidates (one or more)) it monitors. As another example, when instructed to skip PDCCH monitoring, a terminal can skip PDCCH monitoring of some of the search space sets (or one or more coresets, one or more PDCCH monitoring timings, one or more PDCCH candidates) it monitors. Therefore, the application of PDCCH monitoring indications or PDCCH monitoring skip indications can be defined in the technical specifications for one or more search space sets without PDCCH monitoring indications or PDCCH monitoring skip indications, and for one or more search space sets with PDCCH monitoring indications or PDCCH monitoring skip indications. For example, Type 0, Type 0A, Type 1, and Type 2 PDCCH CSS sets can be defined as one or more search space sets that do not have PDCCH monitoring indicators or PDCCH monitoring skip indicators applied. Additionally, a Type 3 PDCCH CSS set can be defined as a search space set that does not have PDCCH monitoring indicators or PDCCH monitoring skip indicators applied. For example, CSS sets can be monitored even during PDCCH monitoring skip periods.

[0106] Optionally, the terminal may be configured or instructed by the base station to apply the PDCCH monitoring skip instruction to one or more search space sets (or one or more CORESETs, one or more PDCCH monitoring times, and one or more PDCCH candidates). The set of one or more search space sets may correspond to the aforementioned SSSG. That is, when the base station configures a specific SSSG, the terminal may skip PDCCH monitoring operations for that specific SSSG (e.g., one or more specific search space sets (or one or more CORESETs, one or more PDCCH monitoring times, and one or more PDCCH candidates)). For example, one or more specific search space sets may be all search space sets (one or more) that can apply the aforementioned PDCCH monitoring skip instruction. In other words, one or more specific search space sets may be the remaining one or more search space sets excluding the one or more search space sets that do not apply the aforementioned PDCCH monitoring skip instruction. In this case, the search space set (one or more) included in a specific SSSG in the configuration and the search space set (one or more) of the terminal's actual application monitoring skip operation may not necessarily match.

[0107] Simultaneously, SSSGs that do not include any search space set can be defined or configured (e.g., empty SSSG, dormant SSSG, etc. (hereinafter referred to as 'empty SSSG')). A terminal can configure up to one empty SSSG within a bandwidth portion or a carrier. When the terminal is instructed to monitor an empty SSSG, the terminal may not monitor any search space set (except for one or more search space sets for which PDCCH monitoring indication or PDCCH monitoring skip indication is not applied). An empty SSSG may not be used as the aforementioned starting SSSG. That is, one or more SSSGs excluding empty SSSGs can be configured to the terminal as one or more starting SSSGs. For example, the terminal may consider an SSSG with a specific ID as an empty SSSG. As another example, when configuring a specific SSSG from the base station, the terminal may perform a PDCCH monitoring skip operation on one or more search space sets included in the configured SSSG. That is, the search space sets included in the configured specific SSSG may match the search space sets for which the terminal actually applies monitoring skip operations. In this scenario, the terminal can perform PDCCH monitoring operations on one or more search space sets that are not included in the configured SSSG.

[0108] The terminal may be configured with one SSSG for PDCCH monitoring skip operations. Optionally, the terminal may be configured with multiple SSSGs for PDCCH monitoring skip operations.

[0109] Figure 4 This is a conceptual diagram illustrating a PDCCH monitoring skipping method according to an exemplary embodiment of the present disclosure.

[0110] Reference Figure 4 The terminal can be configured with multiple SSSGs (i.e., a first SSSG and a second SSSG) from the base station. The base station can instruct the terminal to skip PDCCH monitoring of the first SSSG, the second SSSG, or both the first SSSG and the second SSSG via DCI. For this purpose, the DCI used to instruct skipping PDCCH monitoring may include information about the ID or number of one or more SSSGs.

[0111] Reference Figure 4 The terminal can skip PDCCH monitoring of the second SSSG during a first skip period based on the reception of the first DCI. The terminal can perform PDCCH monitoring on the first SSSG during the first skip period. Additionally, the terminal can skip PDCCH monitoring of both the first and second SSSGs during a second skip period based on the reception of the second DCI. That is, a common PDCCH monitoring skip period for multiple SSSGs can be indicated. The DCI used to indicate the PDCCH monitoring skip may include information about the common PDCCH monitoring skip period for multiple SSSGs. Optionally, PDCCH monitoring skip periods can be indicated separately for each of the multiple SSSGs. The terminal can perform monitoring on the first SSSG and one or more search space sets (or one or more CORESETs, one or more PDCCH monitoring opportunities, one or more PDCCH candidates, etc.) that do not belong to the second SSSG during the first skip period, and can perform monitoring on one or more search space sets (or one or more CORESETs, one or more PDCCH monitoring opportunities, one or more PDCCH candidates, etc.) that do not belong to either the first SSSG or the second SSSG during the second skip period. According to another exemplary embodiment, the PDCCH monitoring skip period can be semi-statically configured to the terminal via higher-layer signaling (e.g., RRC signaling). Similarly, in this case, the PDCCH monitoring skip period can be configured jointly for multiple SSSGs, or the PDCCH monitoring skip period can be configured individually for each SSSG. When the PDCCH monitoring skip operation is applied only to a specific SSSG (e.g., an empty SSSG), the indication or configuration of the PDCCH monitoring skip period or the SSSG monitoring period may be valid only for that specific SSSG.

[0112] SSSG switching operations can be performed by a timer. For example, a terminal configured with a first SSSG and a second SSSG can initialize a timer and start the timer when the first SSSG is switched to the second SSSG (e.g., the time slot where monitoring of the second SSSG begins). The timer value can decrease over time. For example, the timer value can decrease by 1 for each time slot. The terminal can perform a switching operation to a predefined or configured SSSG (e.g., the first SSSG or the default SSSG) when the timer expires (e.g., the time slot where the timer value becomes 0 or the next time slot), and can begin monitoring the SSSG (e.g., the first SSSG or the default SSSG). Optionally, the terminal can be indicated to the DCI (e.g., a DCI indicating SSSG monitoring or SSSG monitoring skipping) to monitor the SSSG after the timer expires. Additionally, when the terminal successfully receives a DCI (e.g., a scheduled DCI) during the timer's running period (e.g., the second SSSG monitoring period), the terminal can reinitialize the timer. Accordingly, the second SSSG monitoring period can be extended. The timer value can be set in units of time slots. For example, the timer value can be set to T time slots (T is a natural number or an integer greater than or equal to 0). The timer value can be set for multiple SSSGs. Alternatively, the timer value can be set individually for each SSSG. Whether the terminal performs the aforementioned timer extension or reinitialization operation during the SSSG monitoring period can be configured via signaling from the base station (e.g., RRC signaling, DCI).

[0113] The PDCCH monitoring skip period can be determined by a timer value. That is, the terminal can be instructed to perform a PDCCH monitoring skip operation for a specific SSSG, and this operation can be performed while the timer for the SSSG is running (e.g., from the time the timer is initialized to the timer's expiration). For example, if the timer value is set to K slots for a specific SSSG (K is a natural number or an integer greater than or equal to 0), then a PDCCH monitoring skip operation for the corresponding SSSG can be performed for K consecutive slots. In other words, the length of the PDCCH monitoring skip period can be K consecutive slots. In this case, the timer can be extended or reinitialized by successfully receiving a DCI. After the PDCCH monitoring skip period, the terminal can perform an SSSG handover operation to a predefined or configured SSSG (e.g., the default SSSG) or to an SSSG monitored before the PDCCH monitoring skip operation.

[0114] As described above, the PDCCH monitoring skip operation can only be performed when a specific SSSG is configured (e.g., an empty SSSG). Alternatively, the PDCCH monitoring skip operation can be performed separately for each SSSG. For example, the time period during which the terminal skips PDCCH monitoring (and the time period during which the terminal performs PDCCH monitoring) can be independent for each SSSG (i.e., the time period can be the same or different for each SSSG).

[0115] Figure 5 This is a conceptual diagram illustrating a PDCCH monitoring skipping method according to another exemplary embodiment of the present disclosure.

[0116] Reference Figure 5 The terminal can be configured from the base station with multiple SSSGs (i.e., the first SSSG and the second SSSG) and can be instructed by DCI to skip PDCCH monitoring of the first SSSG and / or the second SSSG.

[0117] For example, based on the reception of the first DCI, the terminal may be instructed not to perform PDCCH monitoring on the first SSSG during the first skip period. The terminal may perform PDCCH monitoring on the second SSSG during the first skip period. Additionally, the terminal may perform monitoring on one or more search space sets (or one or more CORESETs, one or more PDCCH monitoring times, one or more PDCCH candidates, etc.) that do not belong to the first and second SSSGs during the first skip period. Based on the reception of the second DCI, the terminal may be instructed not to perform PDCCH monitoring on the second SSSG during the second skip period. The second DCI may be received during the first skip period. For example, the second DCI may be transmitted via a search space set (or PDCCH) belonging to the second SSSG. According to an exemplary embodiment, the monitoring skip period for the first SSSG may be different from the monitoring skip period for the second SSSG. Furthermore, the monitoring skip period for the first SSSG may (partially) overlap with the monitoring skip period for the second SSSG. The terminal may skip the PDCCH monitoring operation on the union of the first and second SSSGs during the overlapping period of the first and second skip periods.

[0118] Simultaneously, the PDCCH monitoring skip operation can be performed together with the DRX operation. The terminal performing the PDCCH monitoring skip operation can be configured or instructed by the base station for (one or more) initial SSSGs through the above method, and PDCCH monitoring can be performed on (one or more) initial SSSGs at the beginning of each DRX cycle.

[0119] The base station may instruct the terminal to perform a PDCCH monitoring skip operation without specifying the PDCCH monitoring skip period (or the end time of the PDCCH monitoring skip operation). That is, the DCI indicating skipping PDCCH monitoring may not include information about the PDCCH monitoring skip period (or the end time of the PDCCH monitoring skip operation). In this case, the terminal may continuously perform the PDCCH monitoring skip operation until a separately defined or configured / indicated time (e.g., wake-up time) occurs, and when the separately defined or configured / indicated time (e.g., wake-up time) occurs, the PDCCH monitoring skip operation may be stopped at that time. In other words, at the corresponding time, the terminal may resume PDCCH monitoring operation on (one or more) SSSGs monitored before the PDCCH monitoring skip operation was indicated.

[0120] The wake-up time can be a specific time slot, the start time of a specific time slot, or the boundary between specific time slots. The wake-up time can be predefined in the technical specifications. The wake-up time can be semi-statically configured to the terminal. For example, the wake-up time can be configured to the terminal via an RRC signaling procedure. In this case, the wake-up time can occur periodically and repeatedly, and the configuration information of the wake-up time can include periodicity, time offset (e.g., time slot offset or symbol offset), etc. Optionally, the wake-up time can be dynamically indicated by a DCI. The DCI can be a different DCI than the DCI indicating a PDCCH monitoring skip operation. The DCI can be a group common DCI (e.g., DCI format 2_0, 2_6, etc.). Optionally, the DCI can be a scheduling DCI (e.g., DCI format 0_0, 1_0, 0_1, 1_1, 0_2, 1_2, etc.). Optionally, the wake-up time can be expressed as the time distance from the start time of the PDCCH monitoring skip operation (e.g., time slot offset, duration). In other words, when the terminal is not instructed to skip the PDCCH monitoring period via DCI, the terminal can perform the PDCCH monitoring skip operation for a duration that is configured separately (e.g., via RRC signaling).

[0121] Combined PDCCH handover and PDCCH monitoring skip

[0122] PDCCH switching operations and PDCCH monitoring skip operations can be configured together. For example, a PDCCH switching operation (i.e., the operation that performs PDCCH monitoring) can be applied to one time period, and a PDCCH monitoring skip operation can be applied to another time period. Alternatively, a PDCCH switching operation (i.e., the operation that performs PDCCH monitoring) can be applied to one (or more) SSSGs, and a PDCCH monitoring skip operation can be applied to some (or more) other SSSGs. In this case, the SSSGs to which the PDCCH switching operation (i.e., the operation that performs PDCCH monitoring) is applied and the SSSGs to which the PDCCH monitoring skip operation is applied can be different from each other. The adaptive PDCCH monitoring operation (i.e., the PDCCH switching operation and / or the PDCCH monitoring skip operation) applied to each SSSG can be configured semi-statically. Optionally, the SSSGs to which the PDCCH switching operation (i.e., the operation that performs PDCCH monitoring) is applied and the SSSGs to which the PDCCH monitoring skip operation is applied can be different from each other. Both the PDCCH switching operation and the PDCCH monitoring skip operation can be applied to the same SSSG (e.g., at different time points).

[0123] Figure 6 This is a conceptual diagram illustrating a method for simultaneously performing PDCCH switching and PDCCH monitoring skipping according to an exemplary embodiment of the present disclosure.

[0124] Reference Figure 6 The terminal can monitor two SSSGs (i.e., the first SSSG and the second SSSG) based on the configuration from the base station. In this case, either a PDCCH monitoring skip operation or a PDCCH handover operation can be indicated to the terminal via DCI according to the method described above. For example, the terminal can skip PDCCH monitoring in the second time period based on the DCI received in the first time period. Alternatively, the terminal can switch from the first SSSG to the second SSSG based on the DCI received in the third time period and monitor the second SSSG in the fourth time period. Alternatively, the terminal can skip PDCCH monitoring in the fifth time period based on the DCI received in the fourth time period. In this case, the length of the terminal's PDCCH monitoring skip period (i.e., the second time period or the fifth time period) can be determined by timer operation. For example, the terminal can start a timer when entering the PDCCH monitoring skip period and can perform a PDCCH monitoring skip operation until the timer expires (e.g., the time slot where the timer expires). The timer value can be set to an absolute time (e.g., A ms) or the number of time slots (e.g., B time slots (one or more)) and can be decremented by 1 per unit time (e.g., 1 ms) or per time slot. The timer expires when its value becomes 0. Optionally, the length of the PDCCH monitoring skip period can be configured or indicated by the base station to the terminal.

[0125] When SSSG switching and PDCCH monitoring skipping are performed together as in the exemplary embodiments described above, the SSSG monitoring operation of the terminal in the period following the end of the PDCCH monitoring skipping period (e.g., the third or sixth period) can be defined. Simultaneously, a default SSSG can be configured for the terminal to perform timer-based SSSG switching operations. When the timer expires while monitoring an SSSG, the terminal can switch to the default SSSG. In the exemplary embodiments described above, the first SSSG can be the default SSSG. The SSSG monitored by the terminal in the period immediately following the PDCCH monitoring skipping period can be determined by the SSSG monitored in the period immediately preceding the PDCCH monitoring skipping period. For example, the terminal can perform a PDCCH skipping operation in the second period, and when the first SSSG, which is the default SSSG, is monitored in the first period immediately preceding the second period, the terminal can monitor the first SSSG monitored in the first period in the third period immediately following the second period. As another example, the terminal can perform a PDCCH skipping operation in the fifth period, and can monitor the second SSSG instead of the default SSSG in the fourth period immediately preceding the fifth period. In this case, several methods can be considered for the terminal to identify the SSSG to be monitored in the sixth time period, which is the period immediately following the fifth time period.

[0126] As a first method, when the terminal enters the PDCCH monitoring skip period (i.e., the fifth period), the timer for the SSSG (i.e., the second SSSG) monitored in the previous period can be terminated or expired. The terminal can monitor the default SSSG (i.e., the first SSSG) in the period following the PDCCH monitoring skip period (i.e., the fifth period) (i.e., the sixth period).

[0127] As a second method, when entering the PDCCH monitoring skip period (i.e., the fifth period), the terminal can pause the timer for the SSSG (i.e., the second SSSG) monitored in the previous period. The timer can be stopped during the PDCCH monitoring skip period (i.e., the fifth period). The terminal can resume the timer at the end of the PDCCH monitoring skip period (i.e., the fifth period), and can resume monitoring operations for the previous SSSG (i.e., the second SSSG) in the period following the PDCCH monitoring skip period (i.e., the sixth period).

[0128] As a third method, the terminal can continue counting the timer for the SSSG (i.e., the second SSSG) monitored in the previous period during the PDCCH monitoring skip period (i.e., the fifth period). When the timer expires at the end of the PDCCH monitoring skip period (i.e., the fifth period), the terminal can monitor the default SSSG (i.e., the first SSSG) in the period following the PDCCH monitoring skip period (i.e., the sixth period). On the other hand, if the timer has not expired when the PDCCH monitoring skip period (i.e., the fifth period) ends, the terminal can resume monitoring the previous SSSG (i.e., the second period) in the period following the PDCCH monitoring skip period (i.e., the sixth period).

[0129] The above method can be applied regardless of the SSSG monitored by the terminal in the period immediately preceding the PDCCH monitoring skip operation. For example, the above method can be applied equally even when the terminal monitors the default SSSG in the period immediately preceding the PDCCH monitoring skip period.

[0130] The aforementioned PDCCH monitoring indication and PDCCH monitoring skip indication can be executed according to the same DCI format (or the same DCI, a specific field of the same DCI format, etc.). For example, a specific field of the DCI format (e.g., the PDCCH monitoring adaptation indication field) can indicate one of multiple code points. In this case, a PDCCH monitoring operation or PDCCH switching operation can be indicated by a portion of the multiple code points, and a PDCCH monitoring skip operation can be indicated by another portion of the multiple code points. For example, the field can be configured with two bits, where code point '00' can be used to indicate a PDCCH monitoring skip, and at least some of code points '01', '10', and '11' can be used to indicate a PDCCH monitoring operation or a PDCCH switching operation. The same DCI format can be a DCI format transmitted via a PDCCH including a Cyclic Redundancy Check (CRC) scrambled by the same RNTI. The same DCI format can also be a DCI format transmitted via the same search space set. The same DCI format can be one of the aforementioned DCI formats (e.g., DCI formats 2_0, 2_6, 0_0, 1_0, 0_1, 1_1, 0_2, 1_2, etc.).

[0131] When the DCI format instructing PDCCH monitoring adaptation operation is a downlink or uplink scheduled DCI (e.g., DCI formats 0_0, 1_0, 0_1, 1_1, 0_2, 1_2, etc.), the DCI format can schedule data channels (e.g., PDSCH, PUSCH). When the DCI format is a downlink scheduled DCI and the data channel is PDSCH, the terminal can send a HARQ-ACK to the base station for PDSCH. The base station can identify whether the terminal has applied PDCCH monitoring adaptation operation by receiving the HARQ-ACK.

[0132] Optionally, even when the DCI format instructing PDCCH monitoring adaptation operation is a downlink or uplink scheduled DCI (e.g., DCI formats 0_0, 1_0, 0_1, 1_1, 0_2, 1_2, etc.), the DCI format may not schedule data channels (e.g., PDSCH, PUSCH). Optionally, when the DCI format instructing PDCCH monitoring adaptation operation is not a scheduled DCI (e.g., DCI formats 2_0, 2_6, etc.), the DCI format may not schedule data channels (e.g., PDSCH, PUSCH). In this case, even without a PDSCH scheduled by the DCI, the terminal can still send a HARQ-ACK to the base station for receiving the DCI. The timing of sending the HARQ-ACK can be pre-configured to the terminal or indicated by the DCI, and the timing of sending the HARQ-ACK (e.g., the time slot for sending the HARQ-ACK) can be determined based on the timing of receiving the DCI (e.g., the time slot for receiving the DCI). Whether to send a HARQ-ACK can be determined based on the type of HARQ-ACK codebook configured for the terminal or generated by the terminal. For example, when the terminal performs a HARQ-ACK feedback operation based on a specific type of HARQ-ACK codebook (e.g., a type 2 HARQ-ACK codebook), it can report the HARQ-ACK used for DCI to the base station.

[0133] The base station can use the same DCI format to selectively send information to the terminal indicating whether to monitor a PDCCH monitoring resource set (e.g., one or more SSSGs) or to indicate whether to skip monitoring of the PDCCH monitoring resource set (e.g., one or more SSSGs). Optionally, the base station can use a single DCI to send to the terminal information indicating whether to monitor a PDCCH monitoring resource set (e.g., one or more SSSGs) and to indicate whether to skip monitoring of the PDCCH monitoring resource set (e.g., one or more SSSGs). The DCI (or DCI format) may include information about the one or more SSSGs (e.g., one or more IDs or numbers of the one or more SSSGs). Additionally, the DCI may include information about whether the terminal will monitor the one or more SSSGs or skip monitoring of them. This information may be represented by a single bit (e.g., a one-bit flag).

[0134] Alternatively or additionally, the DCI (or DCI format) may include information about PDCCH monitoring skipped periods (e.g., duration). The information about PDCCH monitoring skipped periods (e.g., duration) may have a value represented by the number N (N is a natural number or an integer greater than or equal to 0) of time slots (one or more). Here, a time slot (i.e., time slot duration) may be a time slot (i.e., time slot duration) of a downlink bandwidth portion (BWP) activated in the cell where the terminal performs PDCCH monitoring operations. Optionally, a time slot (i.e., time slot duration) may be a time slot (i.e., time slot duration) of a bandwidth portion (one or more) of downlink bandwidth portions configured in the cell where the terminal performs PDCCH monitoring operations, determined by predefined rules. This bandwidth portion may be the bandwidth portion (one or more) of configured downlink bandwidth portions with the minimum (or maximum) subcarrier spacing. Optionally, the information about PDCCH monitoring skipped periods (e.g., duration) may be expressed as an absolute time value (e.g., K ms). Optionally, as described above, the information regarding the PDCCH monitoring skip period may include information about the timer used for SSSG switching operations (e.g., timer values).

[0135] Additionally, information regarding the continuous execution of PDCCH monitoring skipping operations by the instruction terminal for the corresponding (one or more) SSSGs until a certain time (e.g., wake-up time) is defined or configured / indicated can be included in the information about the PDCCH monitoring skipping period (e.g., duration). For example, this information can be expressed by representing the value of N as "infinity" or "maximum value". Furthermore, information regarding the execution of PDCCH monitoring by the instruction terminal for the corresponding (one or more) SSSGs can be included in the information about the PDCCH monitoring skipping period (e.g., duration). For example, this information can be expressed by representing the value of N as 0, "none", etc.

[0136] The DCI used to indicate the aforementioned adaptive PDCCH monitoring operation can be sent via a USS set. For example, the adaptive PDCCH monitoring operation can be indicated via a non-backoff DCI (e.g., DCI format 0_1, 1_1, 0_2, 1_2, ...). Alternatively, the adaptive PDCCH monitoring operation can be indicated via a backoff DCI (e.g., DCI format 0_0, 1_0). Therefore, the terminal can be configured such that each SSSG includes at least one USS set. When an empty SSSG is configured to be assigned to the terminal, the terminal can be configured such that each SSSG other than the empty SSSG includes at least one USS set. Optionally, when applying the adaptive PDCCH monitoring method, the base station can be configured or instructed to monitor at least one USS set throughout the entire time period (e.g., during each SSSG monitoring period). In particular, the terminal can be configured or instructed to monitor at least one USS set even during periods indicating PDCCH monitoring skipping. For example, one or more search space sets where PDCCH monitoring skipping operation is not applied may include at least one USS set. Additionally, a DCI indicating the aforementioned adaptive PDCCH monitoring operation can be sent via a type 3CSS set. Therefore, the terminal can be configured such that each SSSG includes at least one USS set or at least one type 3CSS set. Specifically, the terminal can be configured or instructed to monitor at least one type 3CSS set even during periods indicating PDCCH monitoring skipping. For example, one or more search space sets where PDCCH monitoring skipping is not applied may include at least one type 3CSS set. According to the method described above, the terminal can always (e.g., throughout all SSSG monitoring periods) receive a DCI indicating PDCCH monitoring operation, regardless of the SSSG it is monitoring.

[0137] A specific DCI format (e.g., DCI format 2_6) can be used as a wake-up signal. For example, the terminal can determine whether to perform PDCCH monitoring based on the indication information of DCI format 2_6 by transitioning to the DRX on state in the next DRX cycle. In this case, the aforementioned adaptive PDCCH monitoring operation may not be applied to the monitoring of DCI format 2_6. For example, the search space set for monitoring DCI format 2_6 (e.g., the type 3CSS set) may not be included in any SSSG. Alternatively, the search space set for monitoring DCI format 2_6 (e.g., the type 3CSS set) may be included in all SSSGs (one or more), and monitoring of DCI format 2_6 may always be performed, regardless of the SSSG (one or more) monitored by the terminal. Optionally, the search space set (e.g., a type 3CSS set) for monitoring DCI format 2_6 may be included in all SSSGs (one or more) except for the empty SSSG, and monitoring of DCI format 2_6 may always be performed in the remaining (one or more) time slots except for the empty SSSG monitoring period, regardless of whether the terminal is configured or indicated to monitor (one or more) SSSGs. SSSG monitoring operations may be valid only in time slots within the active time. That is, adaptive PDCCH monitoring operations may not be applied in time slots outside the active time.

[0138] In some cases, the transmission reliability (i.e., its reception performance) of the DCI used to indicate adaptive PDCCH monitoring operations may not be high enough. For example, the terminal may fail to receive the DCI. In this situation, the terminal may perform monitoring operations on PDCCH monitoring resources different from those desired by the base station, and the DCI that the base station wants to send to the terminal may not be properly transmitted from the base station to the terminal. In this case, communication between the base station and the terminal may be disabled.

[0139] As a method to address the aforementioned issues, the terminal can perform the adaptive PDCCH monitoring operation only when specific conditions are met. For example, the base station can schedule PDSCH while simultaneously instructing the adaptive PDCCH monitoring operation via downlink scheduling DCI (e.g., DCI formats 1_0, 1_1, 1_2, ...). In this case, if the terminal successfully receives the PDSCH scheduled via DCI, the terminal can perform the operation according to the PDCCH monitoring adaptation instruction via the same DCI. Since the terminal successfully receives the PDSCH, the HARQ-ACK information for the PDSCH can indicate ACK, and the terminal can send the ACK to the base station. On the other hand, if the terminal fails to receive the PDSCH scheduled via DCI, the terminal may not perform the operation according to the PDCCH monitoring adaptation instruction via the same DCI, and can send NACK as HARQ-ACK information for the PDSCH to the base station. Therefore, the base station can know whether the terminal performed the operation according to the PDCCH monitoring adaptation instruction based on the HARQ-ACK information received from the terminal. In other words, if the base station receives an ACK for PDSCH from the terminal, the base station can assume that the terminal has performed the PDCCH monitoring adaptation operation indicated by the DCI, and can send subsequent PDCCHs in the corresponding search space set (e.g., the search space set of one or more handovers). On the other hand, if the base station receives a NACK for PDSCH from the terminal or does not receive HARQ-ACK information for PDSCH, the base station can assume that the terminal has not performed the PDCCH monitoring adaptation operation indicated by the DCI, and can send subsequent PDCCHs in the corresponding search space set (e.g., the previous search space set). Therefore, the possibility of inconsistencies in PDCCH monitoring settings between the base station and the terminal can be reduced. This method may be referred to as (Method 100).

[0140] In (Method 100), the timing of applying the PDCCH monitoring adaptation operation indicated by the DCI can be after a predetermined reference time elapsed from the time of PDSCH reception (e.g., PDSCH reception completion time, the last symbol of the received PDSCH). Optionally, the terminal can be instructed to apply the PDCCH monitoring adaptation operation after a predetermined reference time elapsed from the PDSCH reception time (e.g., PDSCH reception completion time, the last symbol of the received PDSCH). For example, the timing of applying the PDCCH monitoring adaptation operation indicated by the DCI can be the first time slot after the predetermined reference time elapsed from the PDSCH reception completion time. The predetermined reference time can correspond to the time required for the terminal to decode the PDSCH. Optionally, the predetermined reference time can correspond to the time required for the terminal to decode the PDSCH and the time required for the terminal to prepare for the transmission of its corresponding HARQ-ACK. The predetermined reference time can be defined as U symbols (one or more) and / or V time slots (one or more) (U and V are natural numbers). The predetermined reference time can be predefined in the technical specification. For each carrier or bandwidth segment for which PDCCH monitoring operations are performed, the predetermined reference time can be defined as the same or different. The predetermined reference time can be defined as the capability of the terminal, and the terminal can send information about its capability regarding the predetermined reference time supported by the terminal to the base station.

[0141] On the other hand, the application time of the PDCCH monitoring adaptation operation indicated by the DCI may be allowed before the time when the terminal determines the ACK or NACK for the PDSCH. In this case, the terminal may wait until the decoding of the PDSCH is completed (i.e., until the ACK / NACK for the PDSCH is determined), and the PDCCH monitoring adaptation operation may be applied (e.g., in the first time slot that occurs thereafter). Optionally, if the application time of the PDCCH monitoring adaptation operation is earlier than the time when the ACK / NACK for the PDSCH is determined (i.e., when the base station performs a handover indicated by itself before receiving the NACK for the first DCI or determining that no HARQ-ACK has been received, and sends the second DCI according to the SSSG of the handover), the base station may apply the PDCCH monitoring adaptation operation at the corresponding application time. In addition, if the reception of the PDSCH fails and a NACK is determined, the terminal may perform the previous PDCCH monitoring operation without applying the indicated PDCCH monitoring adaptation operation after the time when the NACK is determined (i.e., in the first time slot that occurs after the ACK / NACK is determined). That is, the indicated PDCCH monitoring adaptation operation can be cancelled.

[0142] On the other hand, even using (Method 100), the base station may have difficulty identifying whether the terminal has performed the operation indicated by the PDCCH monitoring adaptation instruction before receiving the HARQ-ACK information sent by the terminal or before determining that no HARQ-ACK information has been received from the terminal. In other words, there may still be ambiguity regarding whether the terminal has performed the PDCCH monitoring adaptation operation. The problems and solutions that may arise from this will be described below.

[0143] HARQ-ACK for PDSCH can be included in a Type 1 HARQ-ACK codebook and sent to the base station. The payload size of the Type 1 HARQ-ACK codebook (i.e., the number of (one or more) HARQ-ACK bits) can be determined based on the number of (one or more) PDSCH candidates (or (one or more) PDCCH candidates indicating the release of semi-persistent scheduling (SPS) PDSCH) that may send (one or more) HARQ-ACK bits corresponding to PDSCH candidates in a given HARQ-ACK transmission time, and each HARQ-ACK bit can indicate ACK or NACK information depending on the reception result of each PDSCH candidate. When the terminal does not actually receive the scheduling DCI corresponding to a certain PDSCH candidate, the HARQ-ACK bit for the corresponding PDSCH candidate can indicate NACK information.

[0144] Figure 7 This is a conceptual diagram illustrating a method for adaptive PDCCH monitoring via downlink DCI indication according to an exemplary embodiment of the present disclosure.

[0145] Reference Figure 7The terminal can receive a DCI (e.g., downlink DCI) in time slot n to receive the scheduled PDSCH. The same DCI can instruct the terminal to monitor the second SSSG from time slot (n+2). Furthermore, the terminal can be instructed (via DCI) to send a HARQ-ACK for PDSCH in time slot (n+3). The terminal can report the HARQ-ACK to the base station using a Type 1 HARQ-ACK codebook. In this case, the size of the Type 1 HARQ-ACK codebook sent in time slot (n+3) can be changed by the PDCCH handover from the first SSSG to the second SSSG. That is, the size of the Type 1 HARQ-ACK codebook when the indication for PDCCH handover to the second SSSG is applied and the size of the Type 1 HARQ-ACK codebook when the indication for PDCCH handover to the second SSSG is not applied can be different from each other. According to the method described above, the base station may need to receive a HARQ-ACK in time slot (n+3) to identify whether the terminal has followed the instruction, and the payload size of the HARQ-ACK in time slot (n+3) can be determined by whether the terminal has followed the instruction. The base station may fail to receive the HARQ-ACK, and the aforementioned ambiguity problem may occur.

[0146] As a method to address the aforementioned problems, the terminal can anticipate the size of the HARQ-ACK codebook (e.g., a Type 1 HARQ-ACK codebook) that does not change based on adaptive PDCCH monitoring operations, the order in which HARQ-ACKs for corresponding PDSCH candidates are mapped to the HARQ-ACK codebook (e.g., a Type 1 HARQ-ACK codebook), and so on. For example, in Figure 5 In an exemplary embodiment, the size of the Type 1 HARQ-ACK codebook when an indication of PDCCH handover to the second SSSG is applied can be the same as the size of the Type 1 HARQ-ACK when an indication of PDCCH handover to the second SSSG is not applied. The above method can be applied, with limitations, to the HARQ-ACK codebook, wherein HARQ-ACKs for PDSCH scheduled by the DCI indicating PDCCH handover are sent. That is, regardless of whether the terminal successfully receives the DCI indicating PDCCH handover, and regardless of whether PDCCH handover is applied, the size of the codebook including HARQ-ACKs for PDSCH scheduled by the DCI can be kept the same. Optionally, when performing adaptive PDCCH monitoring operations, the size of the HARQ-ACK codebook (e.g., the Type 1 HARQ-ACK codebook) can follow a predefined or configured value. As another method, a method of delaying the application time of the adaptive PDCCH monitoring operation can be used. This will be described in more detail below.

[0147] On the other hand, HARQ-ACK corresponding to PDSCH may not be sent. For example, due to transmission priority, timeslot format configuration, lack of processing time, or incorrect indication by the base station of HARQ-ACK transmission resources or timing, the uplink physical channel (e.g., PUCCH, PUSCH) corresponding to PDSCH may not be sent. In this case, a mismatch may occur between the PDCCH monitoring set assumed by the base station and the PDCCH monitoring set assumed by the terminal.

[0148] Therefore, when the terminal successfully receives the PDSCH scheduled by the DCI and sends the corresponding HARQ-ACK to the base station, the terminal can perform operations according to the PDCCH monitoring adaptation instruction from the DCI. If the terminal fails to receive the PDSCH or fails to send the corresponding HARQ-ACK to the base station, the terminal may not perform operations according to the instruction. In this case, the application time of the PDCCH monitoring adaptation operation indicated by the DCI can be after the transmission time of the HARQ-ACK (e.g., the transmission completion time of the HARQ-ACK, the transmission of the last symbol of the PUCCH or PUSCH including the HARQ-ACK). For example, the application time of the PDCCH monitoring adaptation instruction can be the first time slot after the transmission time of the HARQ-ACK (e.g., the transmission completion time of the HARQ-ACK, the transmission of the last symbol of the PUCCH or PUSCH including the HARQ-ACK). Optionally, the terminal can be instructed to perform the PDCCH monitoring adaptation operation after the transmission time of the HARQ-ACK (e.g., the transmission completion time of the HARQ-ACK, the transmission of the last symbol of the PUCCH or PUSCH including the HARQ-ACK). This can be referred to as (Method 110).

[0149] Figure 8 This is a conceptual diagram illustrating a method for indicative adaptive PDCCH monitoring via downlink DCI according to another exemplary embodiment of the present disclosure.

[0150] Reference Figure 8 The terminal may receive a DCI (e.g., downlink DCI) in time slot n to receive the scheduled PDSCH, and may be instructed to monitor the second SSSG (or not monitor the second SSSG) based on the same DCI. Alternatively, the terminal may be instructed (via DCI) to send a HARQ-ACK for the PDSCH in time slot (n+2). In this case, the terminal may be instructed to apply a PDCCH monitoring switch operation to the second SSSG after time slot (n+2), which is the HARQ-ACK transmission time, via (method 110). See reference... Figure 8 The PDCCH monitoring operation can be switched to the second SSSG starting from time slot (n+3).

[0151] The base station may take some time to decode the HARQ-ACK received from the terminal. For example, in Figure 8 In an exemplary embodiment, it can be assumed that the base station requires a time slot (i.e., a time slot duration) to decode the HARQ-ACK received in time slot (n+2). Based on this assumption, the base station may not know whether the terminal has already performed a PDCCH monitoring adaptation operation in time slot (n+3). If the terminal is instructed to perform PDSCH rate matching for a certain CORESET, the PDSCH rate matching operations performed by the base station and the terminal for the CORESET in time slot (n+3) may differ from each other. As a result, the PDSCH reception performance of the terminal in time slot (n+3) may degrade.

[0152] To address the aforementioned issues, the application time of the PDCCH monitoring adaptation indication can be a time elapsed after a reference time from the completion time of the terminal's HARQ-ACK transmission (e.g., the last symbol of the PUCCH or PUSCH including the HARQ-ACK transmission) (e.g., the first time slot after the reference time has elapsed). Optionally, the terminal can be instructed or configured to perform PDCCH monitoring adaptation operations after a reference time has elapsed from the completion time of the HARQ-ACK transmission. The reference time can correspond to a time that includes the time required for the base station to decode the HARQ-ACK or the uplink physical channel (e.g., PUCCH, PUSCH) including the HARQ-ACK. The reference time can be defined as X symbols (one or more) and / or Y time slots (one or more) (X and Y are natural numbers). The reference time can be predefined in the technical specification. The reference time can be defined as the same or different for each carrier or bandwidth portion for which PDCCH monitoring operations are performed. This method can be referred to as (Method 111).

[0153] In methods 110 and 111, when the terminal is instructed to perform a PDCCH monitoring adaptation operation before the aforementioned time point, the terminal may ignore the instruction. Alternatively, when the terminal is instructed to perform a PDCCH monitoring adaptation operation before the aforementioned time point, the terminal may wait until the aforementioned time point and then apply the PDCCH monitoring adaptation operation at a time after the aforementioned time point (e.g., the first time slot after the aforementioned time point).

[0154] As another approach, when the terminal successfully receives the PDSCH scheduled by the DCI and determines that the corresponding HARQ-ACK will be sent to the base station, the terminal can perform PDCCH monitoring and adaptation operations according to the DCI's instructions. Conversely, when the terminal fails to receive the PDSCH or determines that the corresponding HARQ-ACK will not be sent to the base station, the terminal may not perform PDCCH monitoring and adaptation operations according to the DCI's instructions. In this case, the time at which the HARQ-ACK is determined to be sent to the base station can be determined based on the transmission time of the uplink physical channel (e.g., PUCCH or PUSCH) including the HARQ-ACK and a predetermined reference time corresponding to the time required to prepare for the corresponding transmission (i.e., the preparation time). For example, the time at which the terminal can determine that the HARQ-ACK will be sent to the base station can be such that this time is at least earlier than the start time of the transmission of the uplink control channel (e.g., PUCCH or PUSCH) transmitting the HARQ-ACK by the predetermined reference time corresponding to the preparation time. Simultaneously, the terminal can determine that the time at which the HARQ-ACK will be sent to the base station may be later than the time when the PDSCH reception is completed (e.g., the end time of the last symbol of the PDSCH) and a predetermined reference time corresponding to the time required to decode the PDSCH. This may be referred to as (Method 120).

[0155] In (method 120), the application time of the PDCCH monitoring adaptation operation indicated by the DCI can be after the time when it is finally determined whether to send HARQ-ACK. For example, the application time of the PDCCH monitoring adaptation indication can be the first time slot after the time when it is finally determined whether to send HARQ-ACK, the first time slot after a reference time elapsed from the time when it is finally determined whether to send HARQ-ACK, etc. Optionally, the terminal can be instructed to perform the PDCCH monitoring adaptation operation after the time when it is finally determined whether to send HARQ-ACK. The terminal may not send HARQ-ACK to the base station for reasons such as conflicts with other uplink transmissions, transmission priority, transmission power, etc. When the terminal does not send HARQ-ACK to the base station, the terminal may not perform the operation according to the PDCCH monitoring adaptation indication. In addition, when the HARQ-ACK transmission resources and / or HARQ-ACK transmission timing indicated by the DCI are invalid, the terminal may not perform the operation according to the PDCCH monitoring adaptation indication by the DCI.

[0156] Multiple PDSCHs can be scheduled by the downlink DCI. These multiple PDSCHs can be repeated transmissions for the same TB. Optionally, the multiple PDSCHs can be transmissions for different TBs. In this case, the above method can be implemented with some modifications. For example, when multiple PDSCHs or multiple TBs are scheduled by the downlink DCI, the terminal can follow the adaptive PDCCH monitoring instruction of the DCI only when at least one PDSCH or at least one TB is determined to be acknowledged (ACK). In this case, the application time of the indicated PDCCH monitoring adaptation operation can be before the reception completion time of the last PDSCH. As another example, when multiple PDSCHs or multiple TBs are scheduled by the downlink DCI, the terminal can follow the adaptive PDCCH monitoring instruction of the DCI only when at least one PDSCH or at least one TB is determined to be acknowledged (ACK) and an ACK is sent to the base station. As another example, when multiple PDSCHs or multiple TBs are scheduled by the downlink DCI, the terminal can follow the adaptive PDCCH monitoring instruction of the DCI only when at least one PDSCH or at least one TB is determined to be ACK and an ACK is determined to be sent to the base station.

[0157] When the downlink DCI does not schedule PDSCH, whether to execute the adaptive PDCCH monitoring operation indicated by the DCI and the application time of the adaptive PDCCH monitoring operation can be determined by the uplink transmission triggered by the DCI (e.g., whether to execute the uplink transmission, the transmission time of the uplink transmission, etc.). For example, when the downlink DCI triggers an aperiodic CSI report, the terminal may execute the PDCCH monitoring adaptation operation indicated by the DCI only when the aperiodic CSI report is sent to the base station. Optionally, similar to the HARQ-ACK case described above, when the downlink DCI triggers an aperiodic CSI report, the terminal may execute the PDCCH monitoring adaptation operation indicated by the DCI only when it is determined that the aperiodic CSI report has been sent to the base station. The application time of the PDCCH monitoring adaptation operation can be determined by the transmission time of the uplink physical channel (e.g., PUCCH or PUSCH) including the aperiodic CSI report and the reference time corresponding to the preparation time of the corresponding transmission.

[0158] When the indication for adaptive PDCCH monitoring operation is via uplink DCI (e.g., DCI format 0_0, 0_1, 0_2, ...), the terminal may perform the DCI-indicated PDCCH monitoring adaptation operation only when the PUSCH scheduled by the DCI is sent to the base station. In this case, the application time of the PDCCH monitoring adaptation indication may be after the PUSCH transmission completion time (e.g., the last symbol of the PUSCH). Alternatively, the terminal may perform the DCI-indicated PDCCH monitoring adaptation operation only when it is determined that the PUSCH scheduled by the DCI has been sent to the base station. The time at which the terminal determines whether to actually transmit the PUSCH may be determined by the PUSCH transmission time and a reference time corresponding to the preparation time of the corresponding transmission. For example, the time at which the terminal determines whether to actually transmit the PUSCH may (at the latest) be earlier than the PUSCH transmission start time (e.g., the start time of the first symbol of the PUSCH) by the reference time corresponding to the preparation time.

[0159] Exemplary embodiments of this disclosure can be implemented as program instructions that are computer-executable and recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, or combinations thereof. The program instructions recorded on the computer-readable medium may be specifically designed and configured for this disclosure, or may be well-known and available to those skilled in the art of computer software.

[0160] Examples of computer-readable media may include hardware devices such as ROM, RAM, and flash memory, which are specifically configured to store and execute program instructions. Examples of program instructions include machine code generated, for example, by a compiler, and high-level language code that can be executed by a computer using an interpreter. The exemplary hardware devices described above may be configured to operate as at least one software module to perform embodiments of this disclosure, and vice versa.

[0161] While embodiments of the present disclosure and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations may be made herein without departing from the scope of the disclosure.

Claims

1. A method for operating a terminal, comprising: The configuration information of the first search space set group (SSSG) and the second SSSG are received from the base station. Each SSSG in the first SSSG and the second SSSG includes one or more search space sets. The base station receives indication information, which indicates that the second SSSG should perform physical downlink control channel (PDCCH) monitoring. as well as In response to the instruction information, perform PDCCH monitoring on the second SSSG on the serving cell until the timer expires; Determine whether another operation that skips PDCCH monitoring is being executed when the timer expires; as well as In response to determining that the other operation skipping PDCCH monitoring is being performed when the timer expires, after the duration of the other operation skipping PDCCH monitoring has expired, the specific SSSG is monitored. The indication information is dynamically received via downlink control information (DCI).

2. The operating method according to claim 1, wherein, The indication information is transmitted to the terminal by indicating a specific field of the DCI of one of the multiple code points, and when the specific field indicates the first code point among the multiple code points, it indicates that a PDCCH monitoring operation is performed on the second SSSG.

3. The operating method according to claim 1, wherein, The DCI also includes data channel scheduling information, and the terminal receives the data channel from the base station based on the scheduling information.

4. The operating method according to claim 1 further includes: In response to receiving the DCI, a Hybrid Automatic Repeat Request (HARQ) Acknowledgment (ACK) message is sent to the base station, wherein the HARQ ACK message depends on whether the DCI includes a data channel reception response or a response to the DCI itself, which includes data channel scheduling information.

5. The operating method according to claim 1 further includes: In response to receiving the DCI, HARQ ACK information is sent to the base station, wherein the transmission time of the HARQ ACK information is determined to be a predetermined time after the time the indication information is received.

6. The operating method according to claim 1, wherein, The timer value corresponds to one or more time slots and is applied together to multiple SSSGs, and the specific SSSG is the first SSSG.

7. The operating method according to claim 1, wherein, When the second SSSG does not include one or more monitoring opportunities, the terminal does not perform PDDCH monitoring on the second SSSG.

8. The operating method according to claim 1, further comprising: When the indication information indicates that PDCCH monitoring should be skipped, PDCCH monitoring is performed on one or more predefined search space sets during a first duration, wherein the predefined one or more search space sets do not include the type 3 PDCCH common search space set.

9. The operating method according to claim 1, wherein, The terminal performs DRX operation based on discontinuously received DRX configuration information received from the base station, and the terminal performs PDCCH monitoring on one of the first SSSG and the second SSSG pre-configured by the base station during the beginning portion of the DRX cycle's on-duration duration.

10. A method for operating a base station, comprising: The configuration information of the first search space set group (SSSG) and the second SSSG is sent to the terminal, wherein each SSSG in the first and second SSSG includes one or more search space sets; and The instruction information is sent to the terminal, indicating that the physical downlink control channel (PDCCH) monitoring operation be performed on the second SSSG. The indication information is dynamically sent to the terminal via downlink control information (DCI). The indication information allows the terminal to perform PDCCH monitoring on the second SSSG until the timer expires, and after the timer expires, to perform PDCCH monitoring on the specific SSSG. When the timer expires, the indication information allows the terminal to perform PDCCH monitoring on the specific SSSG after the duration of another operation by the terminal that skips PDCCH monitoring.

11. The operating method according to claim 10, wherein, The indication information is transmitted to the terminal by indicating a specific field of the DCI of one of the multiple code points, and when the specific field indicates the first code point among the multiple code points, it indicates that a PDCCH monitoring operation is performed on the second SSSG.

12. The operating method according to claim 10, wherein, The timer value corresponds to one or more time slots and is applied together to multiple SSSGs, and the specific SSSG is the first SSSG.

13. The operating method according to claim 10, further comprising: In response to the DCI, the terminal receives Hybrid Automatic Repeat Request (HARQ) Acknowledgment (ACK) information, wherein the HARQ ACK information depends on whether the DCI includes data channel scheduling information or a response to the reception of the data channel or the DCI itself.

14. The operating method according to claim 10, further comprising: In response to the DCI, HARQACK information is received from the terminal, wherein the reception time of the HARQ ACK information is determined to be a predetermined time after the time when the indication information is received.

15. A terminal, comprising: processor; as well as The transceiver is controlled by the processor. The processor is configured to perform the following operations: The transceiver receives configuration information of a first search space set (SSSG) and a second SSSG from the base station. Each SSSG in the first and second SSSG includes one or more search space sets. The system receives indication information from the base station and through the transceiver, the indication information indicating the operation of physical downlink control channel (PDCCH) monitoring for the second SSSG; and In response to the indication information, the transceiver is used to perform PDCCH monitoring on the second SSSG on the serving cell until the timer expires; Determine whether another operation that skips PDCCH monitoring is being executed when the timer expires; and In response to determining that the other operation skipping PDCCH monitoring is being performed when the timer expires, after the duration of the other operation skipping PDCCH monitoring has expired, the specific SSSG is monitored. The indication information is dynamically received via downlink control information (DCI).

16. The terminal according to claim 15, wherein, The indication information is transmitted to the terminal by indicating a specific field of the DCI of one of the multiple code points, and when the specific field indicates the first code point among the multiple code points, it indicates that a PDCCH monitoring operation is performed on the second SSSG.

Images