Apparatus and method for multi-cell scheduling in wireless communication systems

Abstract

This disclosure relates in general to wireless communication systems, and more specifically to apparatus and methods for multi-cell scheduling in wireless communication systems. The operation method of user equipment (UE) in a wireless communication system may include: receiving configuration information from a base station (BS); designating a plurality of serving cells, including a first serving cell and a second serving cell, as a cell group based on the configuration information; performing PDCCH monitoring operations to receive downlink control information (DCI) for scheduling the cell group in a PDCCH (physical downlink control channel) search space set; receiving DCI from the base station based on the PDCCH monitoring operations; identifying scheduling information for N serving cells belonging to the cell group; and receiving a data channel in at least one of the N serving cells based on the scheduling information.

Description

[Technical Field]

[0001] This disclosure relates in general to wireless communication systems, and more specifically to apparatus and methods for multi-cell scheduling in wireless communication systems. [Background technology]

[0002] Mobile communication systems are a core infrastructure driving the ICT industry, constantly evolving and overcoming the limitations of conventional systems. To provide advanced services in various usage scenarios such as eMBB (enhanced Mobile Broadband), URLLC (Ultra Reliable Low Latency Communication), mMTC (massive Machine Type Communication), ultra-low power, ultra-precision, and ultra-wide coverage, mobile communication systems are continuously striving to secure new communication frequency bands in the mid-band and high-band to achieve diverse performance metrics.

[0003] In particular, to provide a high peak data rate, technology for aggregating multiple carriers at the terminal is essential. Therefore, research is needed to develop methods that maximize aggregation efficiency and minimize control signaling overhead. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Based on the above discussion, this disclosure provides an apparatus and method for multi-cell scheduling in a wireless communication system.

[0005] Furthermore, this disclosure provides an apparatus and method for scheduling a single serving cell among a plurality of scheduling cells in a wireless communication system.

[0006] Furthermore, this disclosure provides an apparatus and method for BD / CCE (blind decoding / control channel element) counting for multi-cell DCI (downlink control information) monitoring in wireless communication systems.

[0007] Furthermore, this disclosure provides an apparatus and method for SCell (secondary cell) dormancy / non-dormancy instruction using multi-cell DCI in a wireless communication system. [Means for solving the problem]

[0008] According to various embodiments of this disclosure, the operation method of user equipment (UE) in a wireless communication system may include: receiving configuration information from a base station (BS); designating a plurality of serving cells, including a first serving cell and a second serving cell, as a cell group based on the configuration information; performing PDCCH monitoring operations to receive downlink control information (DCI) for scheduling the cell group in a PDCCH (physical downlink control channel) search space set; receiving DCI from the base station based on the PDCCH monitoring operations; identifying scheduling information for N serving cells belonging to the cell group; and receiving a data channel in at least one of the N serving cells based on the scheduling information.

[0009] According to various embodiments of this disclosure, a user equipment (UE) in a wireless communication system includes at least one transceiver and a processor operably coupled to the transceiver, the processor receiving configuration information from a base station (BS), designating a plurality of serving cells, including a first serving cell and a second serving cell, into a cell group based on the configuration information, performing PDCCH monitoring operations to receive downlink control information (DCI) for scheduling the cell group in a PDCCH (physical downlink control channel) search space set, receiving DCI from the base station based on the PDCCH monitoring operations, identifying scheduling information for N serving cells belonging to the cell group, and receiving a data channel in at least one of the N serving cells based on the scheduling information.

[0010] According to various embodiments of this disclosure, a method of operating a base station in a wireless communication system includes the steps of: transmitting configuration information to a user equipment (UE); transmitting downlink control information (DCI) to the UE; and transmitting at least one data channel based on scheduling information for N serving cells included in the DCI, where N is a positive integer; the base station includes a plurality of serving cells, including a first serving cell and a second serving cell; the plurality of serving cells are identified as a cell group based on the configuration information; and the plurality of serving cells may include the N serving cells. [Effects of the Invention]

[0011] The apparatus and methods according to various embodiments of this disclosure can reduce control signaling overhead and increase spectral efficiency by scheduling multiple cells using a single DCI (downlink control information) to a terminal configured with carrier aggregation (CA).

[0012] The effects obtained from this disclosure are not limited to those described above, and other effects not described above will be clearly understood by a person with ordinary skill in the art to which this disclosure pertains from the following description. [Brief explanation of the drawing]

[0013] [Figure 1] One embodiment of the present disclosure provides a first embodiment of a single DCI multicell scheduling method. [Figure 2] One embodiment of the present disclosure provides a first embodiment of a method for scheduling a single serving cell in a plurality of scheduling cells. [Figure 3] One embodiment of the present disclosure provides a second embodiment of a method for scheduling a single serving cell in a plurality of scheduling cells. [Figure 4] One embodiment of the present disclosure provides a second embodiment of a single DCI multicell scheduling method. [Figure 5] This is a conceptual diagram illustrating a third embodiment of a single DCI multicell scheduling method, according to one embodiment of the present disclosure. [Figure 6] One embodiment of this disclosure illustrates how the terminal operates. [Figure 7] One embodiment of this disclosure illustrates how a base station operates. [Figure 8] This disclosure shows a diagram illustrating the configuration of a terminal in a wireless communication system according to various embodiments. [Figure 9] This disclosure shows a diagram illustrating the configuration of a base station in a wireless communication system according to various embodiments of this disclosure. [Modes for carrying out the invention]

[0014] The terms used in this disclosure are used solely to describe specific embodiments and are not intended to limit the scope of other embodiments. Singular expressions may include plural expressions unless they have a clearly different meaning in context. Terms used herein, including technical or scientific terms, may have the same meaning as those generally understood by a person of ordinary skill in the art described herein. Terms used herein that are defined in a general dictionary may be interpreted in the same or similar sense as their meaning in the context of the relevant art, and not in an ideal or overly formal sense unless expressly defined herein. In some cases, terms defined herein may not be interpreted in a way that excludes embodiments of this disclosure.

[0015] In the various embodiments of the present disclosure described below, hardware approaches are described as examples. However, since the various embodiments of the present disclosure include techniques that use both hardware and software, the various embodiments of the present disclosure do not exclude software-based approaches.

[0016] Furthermore, in the detailed description and claims of this disclosure, "at least one of A, B, and C" may mean "A only," "B only," "C only," or "any combination of A, B, and C." Also, "at least one of A, B, or C" or "at least one of A, B, and / or C" may mean "at least one of A, B, and C."

[0017] This disclosure generally relates to wireless communication systems, and more specifically to apparatus and methods for multi-cell scheduling in wireless communication systems. Specifically, this disclosure describes techniques for aggregating multiple carriers at a terminal in a wireless communication system, and techniques for efficiently scheduling multiple carriers.

[0018] The terms used in the following description to refer to signals, channels, control information, network entities, and components of devices are illustrative examples for illustrative purposes only. Therefore, this disclosure is not limited to these terms, and other terms with equivalent technical meanings may be used.

[0019] Furthermore, while this disclosure describes various embodiments using terminology used in certain communication standards (e.g., 3GPP (3rd Generation Partnership Project)), this is merely illustrative for illustrative purposes. The various embodiments of this disclosure can be easily modified and applied to other communication systems.

[0020] This disclosure relates to a method for integrating multiple carriers at a terminal in a wireless communication system, and to a method and apparatus for efficiently scheduling multiple carriers. One embodiment of this disclosure is applicable to an NR communication system. Furthermore, in this disclosure, the embodiments are applicable to other communication systems besides NR communication systems (e.g., LTE communication systems, 5G (fifth generation) communication systems, 6G (sixth generation) communication systems, etc.).

[0021] In wireless communication systems (e.g., NR (new radio) communication systems), the numerology applied to physical signals and channels is variable. The numerology is variable to meet the diverse technical requirements of the communication system. In communication systems where cyclic prefix (CP)-based OFDM (orthogonal frequency division multiplexing) waveform technology is applied, the numerology may include subcarrier spacing and CP length (or CP type).

[0022] Table 1 shows a first embodiment of a numerology configuration for a CP-OFDM-based communication system. [Table 1]

[0023] Referring to Table 1, subcarrier intervals can have an exponential relationship of 2 to each other, and CP lengths can be scaled in the same ratio as OFDM symbol lengths. Depending on the frequency band in which the communication system operates, at least some of the numerologies in Table 1 may be supported. In addition, numerologies not listed in Table 1 may be supported in the communication system. For a particular subcarrier interval (e.g., 60 kHz), additional CP types not listed in Table 1 (e.g., extended CPs) may be supported.

[0024] To describe the frame structure of a wireless communication system, the elements constituting the frame structure in the time domain can include subframes, slots, and mini-slots. Subframes can be used as units for transmission, measurement, etc., and their length can be a fixed value (e.g., 1 ms) regardless of the subcarrier interval. Slots can contain consecutive symbols (e.g., 14 OFDM symbols). Unlike the length of subframes, the length of a slot may be variable and inversely proportional to the subcarrier interval.

[0025] Slots can be used in units of transmission, measurement, scheduling, resource setting, and timing (e.g., scheduling timing, HARQ (hybrid automatic repeat request) timing, CSI (channel state information) measurement and reporting timing, etc.). The length of the actual time resource used for transmission, measurement, scheduling, resource setting, etc., may or may not match the length of the slot. Minislots may contain consecutive symbols, and the length of a minislot may be shorter than the length of the slot. Minislots can be used in units of transmission, measurement, scheduling, resource setting, and timing. Minislots (e.g., minislot length, minislot boundaries, etc.) may be predefined in the technical standard or configured (or instructed) on the terminal. The terminal can be configured (or instructed) to use minislots when certain conditions are met.

[0026] A base station can schedule data channels (e.g., PDSCH (physical downlink shared channel), PUSCH (physical uplink shared channel), PSSCH (physical sidelink shared channel)) using some or all of the symbols that make up a slot. In particular, for URLLC transmission, unlicensed bandwidth transmission, transmission in the coexistence of NR and LTE communication systems, and multiple user scheduling on an analog beamforming basis, data channels may be transmitted using only a portion of a slot. A base station can also schedule data channels using multiple slots. Furthermore, a base station can schedule data channels using at least one mini-slot.

[0027] In the frequency domain, the elements that constitute the frame structure can include resource blocks (RBs) and subcarriers. One RB can contain consecutive subcarriers (e.g., 12 subcarriers). The number of subcarriers constituting one RB can be constant, independent of the numerology. In this case, the bandwidth occupied by one RB can be proportional to the subcarrier spacing in the numerology. RBs can be used in transmission and resource allocation units such as data channels and control channels. Resource allocation for data channels can be done in units of RBs or RB groups (e.g., resource block groups (RBGs)). One RBG can contain one or more consecutive RBs. Resource allocation for control channels can be done in units of control channel elements (CCEs). In the frequency domain, one CCE can contain one or more RBs.

[0028] In a wireless communication system, the aforementioned unit time resources (hereinafter referred to as "slots") may include a combination of one or more segments from downlink (DL) segments, flexible segments (or unknown segments), and uplink (UL) segments. Each of the downlink, flexible, and uplink segments may consist of one or more consecutive symbols. Flexible segments may be located between downlink segments and uplink segments, between a first downlink segment and a second downlink segment, between a first uplink segment and a second uplink segment, etc. When a flexible segment is inserted between downlink segments and uplink segments, the flexible segment can be used as a protected segment.

[0029] A slot may contain one or more flexible segments, or it may not contain any flexible segments. A terminal can perform predefined operations in a flexible segment, or operations that are semi-static or periodically set by the base station (e.g., PDCCH (physical downlink control channel) monitoring, SSB (synchronization signal block) reception and measurement, CSI-RS (CSI-reference signal) reception and measurement, downlink SPS (semi-persistent scheduling) PDSCH reception, SRS (sounding reference signal) transmission, PRACH (physical random access channel) transmission, periodically set PUCCH transmission, PUSCH transmission via configured grant (CG), etc.). A flexible symbol may be overridden by a downlink or uplink symbol. If a flexible symbol is overridden by a downlink or uplink symbol, the terminal may perform a new operation in place of an existing operation in that flexible symbol.

[0030] In one embodiment of this disclosure, SSB (synchronization signal block) can mean a set of signals including a synchronization signal and / or a broadcast channel. The synchronization signal may include a PSS (primary synchronization signal), an SSS (secondary synchronization signal), and the broadcast channel may include a PBCH (physical broadcast channel).

[0031] Furthermore, SSB may include reference signals. These reference signals can include DM-RS (demodulation reference signal), CSI-RS (channel state information-reference signal), TRS (tracking reference signal), PRS (positioning reference signal), PT-RS (phase tracking reference signal), etc., for decoding the PBCH. In an NR communication system, SSB can represent an SS / PBCH (synchronization signal / physical broadcast channel) block. SSB may be transmitted periodically, and one or more SSBs may be repeatedly transmitted within a single period.

[0032] The format of a unit time resource (hereinafter referred to as "slot format") can be semi-fixed by higher-level signaling (e.g., RRC (radio resource control) signaling). Information indicating a semi-fixed slot format can be included in system information, and the semi-fixed slot format can be set on a cell-specific basis. Furthermore, the semi-fixed slot format can be additionally set on a terminal-by-terminal basis via terminal-specific higher-level signaling (e.g., RRC signaling). Flexible symbols for cell-specific slot formats can be overridden by terminal-specific higher-level signaling to downlink or uplink symbols. Additionally, slot formats can be dynamically indicated by physical-level signaling (e.g., SFI (slot format indicator) included in DCI (downlink control information)). Semi-fixed slot formats can be overridden by dynamically indicated slot formats. For example, a semi-fixed flexible symbol can be overridden by an SFI to a downlink or uplink symbol.

[0033] A terminal can perform downlink, uplink, and sidelink operations within a bandwidth part (BWP). A bandwidth part can be defined as a set of consecutive RBs (e.g., PRBs (physical resource blocks)) in a frequency domain having a specific numerology. Only one numerology can be used for signal transmission (e.g., transmission of a control channel or data channel) within a single bandwidth part. In this disclosure, the term "signal," when used in a broad sense, can mean any physical signal and channel. A terminal performing an initial connection procedure can obtain initial bandwidth part configuration information from the base station via system information. A terminal operating in an RRC connected state can obtain bandwidth part configuration information from the base station via terminal-specific higher-level signaling.

[0034] The bandwidth portion configuration information may include information about the numerology and / or RB set applied to the bandwidth portion. At least one of the bandwidth portions configured on a terminal can be activated. For example, one uplink bandwidth portion and one downlink bandwidth portion can each be activated within a single carrier. In a TDD (time division duplex) based communication system, a pair of one uplink bandwidth portion and one downlink bandwidth portion can be activated. A base station can configure multiple bandwidth portions on a terminal within a single carrier and can switch the activated bandwidth portions of the terminal.

[0035] In one embodiment, "activation of a certain frequency band (e.g., carrier, bandwidth portion, RB set, LBT (listen before talk) subband, guard band, etc.)" can mean "a state in which a base station or terminal can send and receive signals using that frequency band." Furthermore, "activation of a certain frequency band" can mean "a state in which the RF (radio frequency) filter (e.g., band-pass filter) of a transceiver operates including the frequency band."

[0036] In one embodiment, RB can mean CRB (common RB). Alternatively, RB can mean PRB or VRB (virtual RB). In an NR communication system, CRB can mean a set of RBs (i.e., a common RB grid) that are arranged continuously with respect to a reference frequency (e.g., point A). Carriers, bandwidth portions, etc., can be arranged on the common RB grid. That is, carriers, bandwidth portions, etc., can be composed of CRBs. RBs or CRBs that constitute a bandwidth portion may be called PRBs, and within the bandwidth portion, the CRB index can be appropriately converted to a PRB index. In one embodiment, RB can mean IRB (interlace RB).

[0037] PDCCH can be used to transmit DCI or DCI format to a terminal. The smallest resource unit constituting a PDCCH can be a REG (resource element group). For example, a REG can consist of one RB in the frequency domain and one OFDM symbol in the time domain. DM-RS for decoding the PDCCH can be mapped to some of the REs that make up the REG, and control information (e.g., modulated DCI) can be mapped to the remaining REs. A PDCCH candidate can consist of one CCE or an aggregated CCE. One CCE can consist of multiple REGs. In an NR communication system, CCE aggregation levels 1, 2, 4, 8, 16, etc., can be supported, and one CCE can consist of six REGs.

[0038] A CORESET (control resource set) can be a resource area where a terminal performs blind decoding of a PDCCH. A CORESET can consist of multiple REGs. A CORESET can consist of one or more RBs in the frequency domain and one or more symbols (e.g., OFDM symbols) in the time domain. The symbols constituting a single CORESET can be continuous in the time domain. The RBs constituting a single CORESET can be continuous or discontinuous in the frequency domain. One DCI (e.g., one DCI format, one PDCCH) can be transmitted within one CORESET. Multiple CORESETs may be configured from a cell or terminal perspective, and the time-frequency resource areas to which multiple CORESETs are mapped may or may not overlap.

[0039] CORESET can be set on a terminal during the initial connection procedure. For example, CORESET can be set on a terminal by an initial connection signal (e.g., PBCH, or system information transmitted via PBCH). The ID (identifier) ​​of a CORESET set by an initial connection signal can be 0. A CORESET set by an initial connection signal is sometimes referred to as CORESET0. A terminal operating in RRC idle state can perform monitoring operations with CORESET0 in order to receive the first PDCCH during the initial connection procedure. Not only terminals operating in RRC idle state, but also terminals operating in RRC connected state can perform monitoring operations with CORESET0. CORESET can be set on a terminal by other system information (e.g., SIB1 (system information block type 1)) in addition to system information transmitted via an initial connection signal (e.g., PBCH). For example, a terminal can receive an SIB1 containing CORESET setting information in order to receive a random access response (or Msg2). Furthermore, CORESET can be configured on a device through device-specific higher-level signaling (e.g., RRC signaling).

[0040] The search space can refer to the set of candidate resource areas that a PDCCH can transmit. A terminal can perform blind decoding on each PDCCH candidate within a predefined or base station-configured search space. The terminal can determine if a PDCCH has been transmitted to it by performing a cyclic redundancy check (CRC) on the blind decoding result. If it is determined that the PDCCH is for the terminal, the terminal can receive the PDCCH.

[0041] One or more search spaces can constitute a search space set. A search space can be defined / configured for each CCE integration level, and a search space set can represent the search spaces for each CCE integration level, or the sum of the search spaces for all CCE integration levels. For each CCE integration level, PDCCH candidates can consist of CCEs selected by a hash function predefined within a CORESET or search space occasion. In an embodiment, "search space set" can mean "search space".

[0042] A search space set can be logically associated with one CORESET. A CORESET can be logically associated with one or more search space sets. A common search space set configured via a PBCH can be used to monitor a DCI that schedules a PDSCH for transmitting SIB1. The ID of a common search space set configured via a PBCH can be set to 0. That is, a common search space set configured via a PBCH can be defined as type 0PDCCH common search space set or search space set #0. Search space set #0 can be logically associated with CORESET0.

[0043] Search space sets can be divided into common search space sets and UE-specific search space sets depending on their application or terminal operation. Common DCIs or UE-specific DCIs can be transmitted in common search space sets, and UE-specific DCIs can be transmitted in UE-specific search space sets. For example, common DCIs may include system information, PDSCH resource allocation information including paging messages, power control commands, slot format indicators (SFIs), preemption indicators, etc. UE-specific DCIs may include PDSCH resource allocation information, PUSCH resource allocation information, etc. Multiple DCI formats can be defined depending on the application, and these multiple DCI formats can be distinguished at the terminal by DCI payload, DCI fields, DCI size, RNTI (radio network temporary identifier), etc.

[0044] In one embodiment of this disclosure, the common search space may be referred to as the CSS (common search space), and the set of common search spaces may be referred to as the CSS set. Furthermore, the terminal-specific search space may be referred to as the USS (UE-specific search space), and the set of terminal-specific search spaces may be referred to as the USS set.

[0045] On the other hand, a terminal can support carrier aggregation (CA) technology. That is, a terminal can receive configuration information for multiple carriers from a base station, aggregate multiple carriers, and communicate with the base station using the aggregated carriers. In one embodiment, a carrier can be interpreted as meaning a cell or a serving cell, and each cell and serving cell can be interpreted as meaning a carrier. In an NR communication system, up to 16 carriers can be aggregated to a single terminal. If the maximum carrier bandwidth is 400 MHz, a single terminal can communicate using a bandwidth of up to 6.4 GHz (= 16 × 400 MHz). Therefore, the peak transmission rate of the terminal can be increased. The aggregated carriers can be adjacent to each other in the frequency domain, or they do not have to be adjacent in the frequency domain. Also, multiple carriers can belong to the same frequency band or to different frequency bands. One or more downlink bandwidth parts and one or more uplink bandwidth parts can be set for each carrier, and a sidelink bandwidth part can be further set for a particular carrier. The terminal can perform communications (e.g., transmission, reception, and measurement operations) within the active bandwidth portion of the activated carrier.

[0046] A terminal using a carrier aggregation scheme may have one PCell and one or more SCells. The terminal can determine its PCell through procedures such as initial cell discovery, cell (re)selection, and handover. In contrast, an SCell can be configured in a terminal (e.g., a terminal in the RRC connected state) via signaling messages transmitted from the base station (e.g., RRC signaling messages). SCells can be activated or deactivated. Activation and / or deactivation of SCells can be controlled via signaling messages transmitted from the base station (e.g., DCI (downlink control information), MAC (medium access control), CE (control element), RRC (radio resource control) signaling, etc.). PCells (primary cell) and SCells (secondary cell) can be configured terminal-specifically. For example, the same serving cell can act as a PCell for a first terminal and as an SCell for a second terminal. Alternatively, multiple terminals can use different serving cells as PCells. In a frequency division duplex (FDD) cell, a serving cell may consist of a downlink carrier and / or an uplink carrier. A serving cell may also include multiple uplink carriers and / or multiple downlink carriers. If a serving cell includes multiple uplink carriers, it may include a supplementary uplink carrier. If a serving cell includes multiple downlink carriers, it may include a supplementary downlink carrier. When a terminal operates in dual connectivity mode, embodiments of this disclosure may apply to a secondary cell group (SCG) configured in the terminal, where PCell may mean PSCell.

[0047] When a carrier aggregation scheme is used, the DCI (or PDCCH) that schedules the data channel can be transmitted on the same carrier as the carrier through which the data channel is transmitted. This scheme is sometimes called a self-scheduling scheme. Alternatively, the DCI (or PDCCH) that schedules the data channel can be transmitted on a different carrier than the carrier through which the data channel is transmitted. This scheme is sometimes called a cross-carrier scheduling scheme. Cross-carrier scheduling schemes can be used for purposes such as offloading control channels and controlling interference between control channels. In this case, the data channel may be a data channel containing unicast data or terminal-specific data (e.g., DL-SCH (downlink-shared channel), UL-SCH (uplink-shared channel)). Furthermore, the DCI that schedules the data channel may mean a DCI (or DCI format) having a CRC scrambled by C-RNTI, CS-RNTI, or MCS-C-RNTI. One of the self-scheduling method and the cross-carrier scheduling method can be applied to each carrier or each serving cell.

[0048] In this disclosure, the carrier on which the scheduling DCI is transmitted may be referred to as a scheduling cell. The carrier on which the data channel is transmitted may be referred to as a scheduled cell. When a self-scheduling scheme is used, the scheduling cell may be the same as the scheduled cell. When a cross-carrier scheduling scheme is used, the scheduling cell may be different from the scheduled cell. A terminal can perform PDCCH monitoring operations corresponding to the scheduled cell on the scheduling cell. The association relationship between the scheduling cell and the scheduled cell can be established on the terminal by higher-level signaling (e.g., RRC signaling, MAC CE procedure).

[0049] Furthermore, scheduling cells can be used by base stations to transmit scheduling information to terminals, and scheduled cells can be used to perform data transmission scheduled by scheduling cells.

[0050] In one embodiment, the PDCCH monitoring operation corresponding to a scheduled cell can mean the operation in which a terminal monitors the PDCCH from the scheduling cell, receives scheduling information, and, based on the scheduling information, decides which resources to use to receive data from the scheduled cell. The PDCCH can provide the terminal with scheduling information for downlink data transmission, that is, information on which resource blocks to use and when.

[0051] According to conventional scheduling methods, only a single serving cell can be scheduled by a single DCI. That is, a single DCI contains scheduling information for a single serving cell. Therefore, in order to schedule multiple aggregated cells, multiple DCIs must be transmitted to the terminal, and the control signaling overhead may increase in proportion to the number of aggregated carriers, potentially reducing spectral efficiency. As a method to solve this problem, a method for scheduling multiple serving cells via a single DCI can be considered. In this disclosure, the scheduling method and apparatus described above may be referred to as a multi-cell scheduling method, a single DCI multi-cell scheduling method, etc. Also, DCI may be referred to as a multi-cell DCI, a multi-cell DCI format, etc.

[0052] A serving cell can refer to a cell that provides services to a terminal. In a multi-cell environment, multiple serving cells can transmit data to a terminal simultaneously, but the DCI, which is the actual control information transmitted via PDCCH, contained scheduling information for a single serving cell.

[0053] This disclosure describes a method and apparatus for scheduling multiple serving cells such that a single DCI can include scheduling information for multiple cells.

[0054] [Cell group configuration and multi-cell DCI configuration method] Figure 1 shows a first embodiment of a single DCI multicell scheduling method according to one embodiment of the present disclosure.

[0055] Referring to Figure 1, a terminal can be configured with at least three carriers (or serving cells), and carrier aggregation can be applied to the configured carriers. In this case, multiple serving cells can be simultaneously scheduled by a single DCI transmitted from a single serving cell, i.e., a multi-cell DCI. That is, the base station can coordinate the data transmission schedules of multiple serving cells by a single DCI.

[0056] In this disclosure, the set of serving cells that can be simultaneously scheduled by multi-cell DCI may be referred to as "cell set 101," "candidate cell set," or "serving cell list." Cell set 101 may be configured on a terminal. For example, information about the cell set may be transmitted to the terminal by a higher-level signaling procedure (e.g., RRC signaling, MAC CE). Cell set 101 may be associated with a single scheduling cell. The association may be configured on the terminal based on a higher-level signaling message (e.g., search space set configuration information). Scheduling cell 103 may match any of the scheduled cells 105, 107, or 109 belonging to cell set 101. Alternatively, scheduling cell 103 may be a serving cell that does not belong to the cell set.

[0057] In one embodiment, scheduling cell 103 may be a first scheduling cell. The cell set 101 may also include a first scheduled cell 105, a second scheduled cell 107, and a third scheduled cell 109.

[0058] The terminal can monitor multi-cell DCI in the scheduling cell, and if it successfully receives the multi-cell DCI, it can schedule PDSCH or PUSCH in one or more cells belonging to the cell set. Cells 105 and 107, which are simultaneously scheduled by the multi-cell DCI, may be referred to as the "coscheduled cell set 111," "coscheduled cell," "scheduled cell set," or "scheduled cell list." The "coscheduled cell set 111" may be a subset of the "cell set 101."

[0059] In the first embodiment, the coscheduled cell set 111 can consist of a first scheduled cell 105 and a second scheduled cell 107. In one embodiment, the base station can instantaneously determine the coscheduled cell set 111 for each scheduling. That is, the coscheduled cell set 111 can be dynamically changed for each scheduling opportunity.

[0060] In order for the terminal to successfully acquire scheduling information contained in the multi-cell DCI, it can be instructed to specify the coscheduled cell set 111 that is scheduled by the multi-cell DCI. For example, the information specifying the coscheduled cell set 111 can be included in the multi-cell DCI.

[0061] In one embodiment, the multi-cell DCI may explicitly include a field containing coscheduled cell instruction information. For example, each code point in the field may correspond to each combination of serving cells. The field may have a constant size (i.e., number of bits) regardless of the number of coscheduled cells. For example, the size of the field may be determined by the number of candidate serving cell combinations (or coscheduled cell combinations).

[0062] In other embodiments, the size of another field within the multi-cell DCI (hereinafter referred to as the "first field") may be variable depending on the number of coscheduled cells. For example, the size of the field indicating the resources of a PDSCH or PUSCH (e.g., time resources, frequency resources) can increase or decrease in proportion to the number of coscheduled cells. That is, the size of the first field can be determined independently for each DCI transmission. For example, the first field may consist of M blocks (where M is a natural number). Each block may correspond to instruction information for each serving cell.

[0063] In one embodiment, M can be determined to be the same value as the cardinality of the coscheduled cell set. In this case, the position where the field indicating the coscheduled cell set is mapped within the payload of the multi-cell DCI may be fixed regardless of the size of the first field. To ensure this, the field indicating the coscheduled cell set 111 may be mapped to a position earlier than the first field within the DCI payload (e.g., the MSB (most significant bits) or bits even closer to the MSB). In contrast, the first field may be variable not only in size but also in the position to which it is mapped. The terminal can read the field indicating the coscheduled cell set 111 at the previously fixed bit position to confirm the number of coscheduled cells, determine the size and mapping position of the first field based on the confirmed number of coscheduled cells, and obtain the information contained in the first field. Based on the information contained in the first field, the terminal can perform a PDSCH or PUSCH transmission operation in the indicated serving cell.

[0064] In other embodiments, if a particular code point is not used in a DCI field defined for other purposes, that code point can be utilized for coscheduled cell set instruction. For example, if a particular field (or a particular block within a particular field) in a multi-cell DCI is set to a particular code point, it can be considered that the scheduled cell corresponding to the code point is not scheduled by the multi-cell DCI. The particular field (or a particular block within a particular field) can correspond to a single scheduled cell. In this case, the multi-cell DCI can have as many particular fields as there are serving cells that make up the cell set, regardless of the actual number of cells that are scheduled (e.g., a coscheduled cell set). Equivalently, a particular field can consist of N blocks (where N is a natural number). Each field or block can correspond to instruction information for each serving cell.

[0065] According to another embodiment, N can be determined to be the same value as the cardinality of the cell set. Furthermore, a specific field may indicate a resource of the PDSCH or PUSCH (e.g., a time resource, a frequency resource).

[0066] Similar to the explicit signaling method described above, a terminal can read a specific field at a fixed bit position within the payload of a multi-cell DCI. To ensure terminal operation, all fields mapped to positions preceding a specific field (e.g., the MSB or bits closer to the MSB) can each have a fixed size (i.e., number of bits), regardless of the size of the coscheduled cell set.

[0067] In contrast, fields mapped to a portion after a specific field (for example, the LSB (least significant bits) or bits closer to the LSB) can be variably sized according to the size of the coscheduled cell set 111. Since this does not affect the mapping position of a specific field, terminal operation can still be guaranteed.

[0068] In one embodiment, the downlink multicell DCI may include scheduling information for the PDSCH assigned to each coscheduled cell. In an NR communication system, the downlink multicell DCI format may be referred to as DCI format 1_X (e.g., X=3). The uplink multicell DCI may include scheduling information for the PUSCH of each coscheduled cell.

[0069] In NR communication systems, the uplink multi-cell DCI format is sometimes referred to as DCI format 0_X (e.g., X=3). Multi-cell DCI formats can be distinguished from single-cell scheduling DCI formats by DCI payload size. Generally, multi-cell DCI formats can have larger payloads than single-cell DCI formats scheduling the same cell. However, depending on the RRC or MAC CE settings applied to the terminal, a single-cell DCI format can also have a larger payload than a multi-cell DCI format. Cell set 101 can be applied in common to both multi-cell PDSCH scheduling and multi-cell PUSCH scheduling. However, the coscheduled cell set 111 can be configured to differ in any way between multi-cell PDSCH scheduling and multi-cell PUSCH scheduling.

[0070] Each scheduled cell scheduled by a multi-cell DCI can be assigned one or more PDSCHs. In a single scheduled cell, each PDSCH can have its own unique TB (or DL-SCH (downlink-shared channel)). Alternatively, multiple PDSCHs constituting a PDSCH repetition transmission can be assigned, and multiple PDSCHs can contain the same TB. In this case, the number of PDSCH repetition transmissions for each scheduled cell can be transmitted to the terminal in advance or via the multi-cell DCI that schedules the PDSCH repetition transmission. In addition, each scheduled cell scheduled by a multi-cell DCI can be assigned one or more PUSCHs. In a single scheduled cell, each PUSCH can have its own unique TB (or UL-SCH (uplink-shared channel)). Alternatively, multiple PUSCHs corresponding to the same TB can be repeatedly transmitted. In this case, the number of PUSCH repetition transmissions for each scheduled cell can be transmitted to the terminal in advance or via the multi-cell DCI that schedules the PUSCH repetition transmission.

[0071] A PUSCH assigned to a scheduled cell does not necessarily have to include a TB or UL-SCH. In this case, the PUSCH may include a UCI (e.g., a CSI report). The PUSCH configuration can be indicated by at least a UL-SCH indication field. That is, a UL-SCH indication field included in a multi-cell DCI can indicate to a terminal whether or not a PUSCH assigned to a scheduled cell includes a TB or UL-SCH.

[0072] In one embodiment, a certain scheduled cell can be determined by a predefined rule. For example, a certain scheduled cell can be determined as the serving cell with the smallest serving cell index among the coscheduled cells. The PUSCH assigned to the remaining scheduled cells among the coscheduled cells, excluding a certain scheduled cell, can always include TB or UL-SCH.

[0073] The scheduling information for a multi-cell DCI may include time domain resource allocation (TDRA) information for each scheduled cell's PDSCH or PUSCH (hereinafter referred to as "PDSCH"). TDRA information for multiple cells can be indicated by the TDRA field. Specifically, each code point in the TDRA field may indicate each candidate cell combination that the multi-cell DCI can schedule and the corresponding TDRA information.

[0074] According to the first embodiment, candidate cell combinations that can be co-scheduled for a set of cells may include {first scheduled cell}, {second scheduled cell}, {third scheduled cell}, {first scheduled cell, second scheduled cell}, {first scheduled cell, third scheduled cell}, {second scheduled cell, third scheduled cell}, {first scheduled cell, second scheduled cell, third scheduled cell}, etc. Each candidate cell combination must contain at least one cell.

[0075] TDRA information for each cell combination may include the start symbol and length (or SLIV (start and length indicator value)) of the PDSCH scheduled for each cell constituting the cell combination, the slot offset, the PDSCH mapping type, etc. If the PDSCH is transmitted repeatedly, the TDRA information may further include the number of repetitions. PDSCH (or PUSCH) repetition transmission can be applied to only some of the cells among those simultaneously scheduled by a multi-cell DCI. In this case, the TDRA information can indicate the number of repetitions only for the partial cells. For example, a partial cell may include a cell with PDSCH repetition transmission configured, or a cell with a bandwidth portion activated that has PDSCH repetition transmission configured. In the latter case, the TDRA information (e.g., the number of repetitions) may be updated by bandwidth portion switching.

[0076] In other embodiments, whether or not to repeatedly transmit PDSCH (or PUSCH) can be set commonly for all cells belonging to the cell set.

[0077] In another embodiment, to ensure scheduling flexibility, the number of PDSCH (or PUSCH) repeated transmissions can be set or instructed independently for each serving cell.

[0078] When a cell combination consists of multiple scheduled cells, multiple TDRA information entries corresponding to multiple cells can be specified. In one embodiment, the cell combination and the corresponding TDRA information can be pre-configured in the terminal in the form of a TDRA table via an RRC message. In this case, each codepoint in the TDRA field can specify each entry or row in the TDRA table. Each entry or row can correspond to the cell combination and the corresponding TDRA information described above. Multiple entries can be set for the same cell combination.

[0079] In this case, each serving cell belonging to the cell set must be referenced at least once by the TDRA table. In the same context, each serving cell belonging to the cell set must be referenced at least once by the candidate coscheduled cell combination. That is, each serving cell can be configured as a component of at least one candidate coscheduled cell combination. If a serving cell belongs to a cell set but is not included in the TDRA table entry or coscheduled cell combination, the terminal can consider this an incorrect configuration because the serving cell cannot be scheduled by the multi-cell DCI.

[0080] In the first embodiment, the first scheduled cell, the second scheduled cell, and the third scheduled cell can be referenced at least once by the TDRA table (or candidate coscheduled cell combination). In other words, each serving cell can be indicated (as part of a cell combination) by at least one entry in the TDRA table. Simultaneously, PDSCH frequency domain resource allocation (FDRA) information transmitted through the multi-cell DCI can include information for all serving cells belonging to the cell set. For example, if the number of serving cells belonging to the cell set is N (where N is a natural number, or N is a natural number greater than or equal to 2), the multi-cell DCI can fixedly include N FDRA fields (or N blocks constituting one FDRA field). Each FDRA field (or each block) can indicate the PDSCH (or PUSCH) frequency resource for each serving cell. In other words, all serving cells corresponding to FDRA fields included in a multi-cell DCI can each be referenced at least once by the TDRA table (or candidate coscheduled cell combination).

[0081] In the second embodiment, each entry (or row) in the TDRA table can contain TDRA information (or information indicating TDRA information) for all serving cells belonging to the cell set. For example, if the number of serving cells belonging to the cell set is N, each row in the TDRA table can contain N pieces of information indicating TDRA information for each serving cell. In this case, the terminal can identify coscheduled cells (e.g., M coscheduled cells) through the fields of the multi-cell DCI described above, and obtain time domain resource allocation information for coscheduled cells based on the M pieces of information corresponding to the identified coscheduled cells out of the N pieces of information corresponding to the code points in the TDRA field. The remaining (NM) pieces of information indicating TDRA information can be ignored. Based on the above-described information, the terminal can perform the corresponding PDSCH or PUSCH transmission operation.

[0082] The above-described embodiment can be extended to take bandwidth portions into consideration. Each entry (or row) in the TDRA table can contain TDRA information (or information indicating TDRA information) for all bandwidth portions of all serving cells belonging to the cell set. For example, if the number of serving cells belonging to the cell set is N and each serving cell has L bandwidth portions, then each row in the TDRA table can contain N*L pieces of information indicating the bandwidth. The terminal can identify coscheduled cells (e.g., M coscheduled cells) and the active bandwidth portion of each coscheduled cell via the fields described above in the multi-cell DCI, and can obtain time-domain resource allocation information for coscheduled cells based on the M pieces of information corresponding to the active bandwidth portion of the identified coscheduled cell, out of the N*L pieces of information corresponding to the code point in the TDRA field. At this time, the remaining (N*LM) pieces of information indicated by the code point can be ignored. Based on the M pieces of information corresponding to the active bandwidth portion of the coscheduled cell, the terminal can perform the corresponding PDSCH or PUSCH transmission operation.

[0083] In one embodiment, the number of FDRA fields (or the number of blocks constituting an FDRA field) included in the multi-cell DCI is variable. For example, the multi-cell DCI may include FDRA fields (or blocks within an FDRA field) corresponding to serving cells included in a coscheduled cell set, but may not have FDRA fields (or blocks within an FDRA field) for the remaining serving cells belonging to the cell set. When the variable number of FDRA fields or blocks is M (where M is a natural number), the value of M can be determined by the size of the coscheduled cell set and can be indicated to the terminal by the multi-cell DCI. That is, the terminal can determine the value of M, i.e., the number of FDRA fields or blocks, based on the multi-cell DCI, and from this, it can determine the number of FDRA fields or blocks, and the position of other fields in the DCI (e.g., the position of bits (sequences) in the payload), and obtain information corresponding to the fields. In other words, the M value can be determined by a specific field with a fixed length within the DCI, and other fields of the DCI can be mapped to positions earlier than the FDRA field (e.g., bits (sequences) closer to the MSB).

[0084] PDSCH or PUSCH (hereinafter referred to as "PDSCH") scheduled by multi-cell DCI may be dropped. A terminal may omit the operation of receiving a PDSCH if the PDSCH scheduled by multi-cell DCI meets certain conditions. For example, a PDSCH that overlaps with an uplink symbol (e.g., a semi-fixed uplink symbol) or an uplink resource (e.g., a PRACH resource) may be dropped. Whether or not a scheduled PDSCH is received (or dropped) can be determined by the terminal for each scheduled cell. If multiple PDSCHs are scheduled in a single cell, whether or not they are received (or dropped) can be determined for each PDSCH or PDSCH instance. Consequently, the number of cells scheduled by multi-cell DCI and the number of cells in which the terminal actually performs the PDSCH receiving operation do not have to match. A terminal may perform the PDSCH receiving operation in some of the coscheduled cells. If the conditions are met in all scheduled cells, the terminal may not perform any PDSCH receiving operation corresponding to the received multi-cell DCI. Alternatively, the terminal may not expect the conditions to be met in all scheduled cells; that is, the terminal may expect a valid PDSCH to be assigned in at least one scheduled cell.

[0085] In multi-cell PUSCH scheduling, a PUSCH may not contain a TB (or UL-SCH). A PUSCH without a TB can be assigned to at most a single cell in a coscheduled cell set. A UCI may be mapped to and transmitted for a PUSCH (or PUSCH resource). A UCI may contain at least a CSI (or CSI report, beam report). PUSCHs without a TB and / or PUSCHs containing a CSI do not have to be dropped. For example, a terminal does not have to expect the resources of a PUSCH without a TB and / or a PUSCH containing a CSI to overlap with a downlink symbol (e.g., a semi-fixed downlink symbol) or downlink resource (e.g., an SSB resource). If a CSI is multiplexed for repeated PUSCH transmissions, the CSI may be multiplexed across one or two PUSCHs (or PUSCH instances). For example, the CSI may be multiplexed across the earliest PUSCH (or PUSCH instance) transmitted by the terminal. When PUSCH repetitive transmission is performed based on two TCIs or two SRS resource sets, the CSI can be multiplexed into one PUSCH per TCI or SRS resource set, i.e., a total of two PUSCHs. Therefore, the CSI transmission performance can be improved by the macrodiversity effect.

[0086] When multiple carriers are configured on a terminal, these multiple carriers can form multiple cell sets. That is, for a terminal configured with multiple carriers, one or more sets of cells can be configured that can be simultaneously scheduled by a multi-cell DCI. For example, a first DCI can simultaneously schedule serving cells belonging to a first cell set, and a second DCI can simultaneously schedule serving cells belonging to a second cell set. The first and second DCIs can be transmitted from the same serving cell in the same DCI format. In this case, it is difficult for the terminal to determine which cell set the received DCI has scheduled without prior information. Therefore, information indicating the cell set to be scheduled can be included in the DCI and dynamically transmitted to the terminal. The field indicating the cell set can have a fixed length and can be mapped to a position earlier (e.g., a bit (sequence) closer to the MSB) than a field with a variable length depending on the size of the coscheduled cell set within the multi-cell DCI.

[0087] In one embodiment, the first cell set and the second cell set can be distinguished by different carrier indicators (e.g., n_CI). Furthermore, scheduled cells belonging to the first cell set cannot belong to the second cell set.

[0088] As described above, the terminal can perform PDCCH monitoring operations for scheduling the cell set in a scheduling cell that is interrelated with the cell set. For this purpose, a search space set for monitoring the multi-cell DCI format can be set in the scheduling cell. The search space set can include PDCCH candidates. The terminal can perform blind detection (BD) on the PDCCH candidates and perform channel estimation on the CCEs to which the PDCCH candidates are mapped. In this case, the number of BDs performed by the terminal for multi-cell scheduling on the cell set and the number of CCEs for channel estimation can be considered as operations on any one scheduled cell, and the number of BDs and CCEs can be counted for any one of the scheduled cells. In one embodiment, the scheduled cell may be referred to as a reference cell. The number of BDs performed by the terminal for multi-cell scheduling and the number of CCEs for channel estimation may not be counted for the scheduled cell, rather than for the reference cell.

[0089] A reference cell can be set on a terminal by a base station. For example, a cell on which a search space set for multi-cell scheduling is set can be considered a reference cell. Also, in one embodiment, if a cell scheduling a cell set coincides with any of the scheduled cells in the cell set, the matching cell can be considered a reference cell. Even if a cell scheduling a cell set coincides with any of the scheduled cells in the cell set, i.e., the first scheduled cell 105, if a search space set for monitoring multi-cell DCI is set on a second scheduled cell 107 that is different from the first scheduled cell 105, the second scheduled cell 107 can be considered a reference cell. The number of DCI format sizes that a terminal monitors for a cell set can be counted relative to the reference cell. If the number of DCI format sizes that a terminal can monitor on the reference cell exceeds an upper limit (e.g., 3 or 4), the sizes of the first DCI format and the second DCI format monitored by the terminal can be aligned with each other, and the number of DCI sizes can be reduced.

[0090] On the other hand, in conventional carrier aggregation technology, a single serving cell can be restricted to being scheduled by only one scheduling cell. For example, if a serving cell is configured to self-schedule from itself, it does not need to be configured to cross-carrier schedule from other serving cells. Conversely, if a serving cell is configured to cross-carrier schedule from other serving cells, it does not need to be configured to self-schedule from itself. Alternatively, a serving cell does not need to be configured to cross-carrier schedule from two different serving cells simultaneously. If a single serving cell is configured to be scheduled from multiple scheduling cells, the terminal must perform PDCCH monitoring operations on the serving cell with multiple scheduling cells, which can complicate the PDCCH candidate mapping rules when considering the upper limit on the number of BD / CCEs that the terminal can perform on the serving cell. Ultimately, the implementation complexity of the terminal can increase. Therefore, it is preferable to limit the number of scheduling cells as described above.

[0091] On the other hand, the multi-cell scheduling method described above can be used together with the single-cell scheduling method. The first scheduled cell 105 set up in the terminal can be scheduled from the first scheduling cell 103 by multi-cell DCI, and the second scheduled cell 107 can be scheduled from the second scheduling cell by single-cell DCI. In one embodiment, the second scheduling cell may be the same as the first scheduling cell. For example, the first scheduling cell, i.e., a single serving cell, can schedule PDSCH or PUSCH to multiple scheduled cells based on multi-cell DCI or single-cell DCI.

[0092] In other embodiments, the second scheduled cell 107 may be identical to the first scheduled cell 105. The first scheduled cell 105, i.e., a single serving cell, can be scheduled by multi-cell DCI from the first scheduling cell 103 and simultaneously by single-cell DCI from the second scheduling cell. That is, a single serving cell can be configured to be scheduled by two scheduling cells. However, unlike the conventional method described above, when multi-cell scheduling and single-cell scheduling are mixed, the above configuration may be effective if certain conditions are met. This is described in more detail by the following embodiments.

[0093] Figure 2 shows a first embodiment of a method for scheduling a single serving cell in a plurality of scheduling cells according to one embodiment of the present disclosure.

[0094] Figure 3 shows a second embodiment of a method for scheduling a single serving cell in a plurality of scheduling cells according to one embodiment of the present disclosure.

[0095] Referring to Figures 2 and 3, the first scheduled cell 201 can belong to the cell set 203 and can be scheduled by a multi-cell DCI from the first scheduling cell 205. Simultaneously, the first scheduled cell 201 can be scheduled by a single-cell DCI from the second scheduling cell 207.

[0096] Referring to Figure 2, the first scheduled cell 201 can be set as the reference cell 209 of the cell set. The reference cell can mean the serving cell from which BD / CCEs for multi-cell DCI monitoring are counted. That is, the number of BD / CCEs corresponding to multi-cell DCI monitoring can be counted for the first scheduled cell 201. In this case, the number of BD / CCEs corresponding to multi-cell DCI monitoring in the first scheduling cell 205 and the number of BD / CCEs corresponding to single-cell DCI monitoring in the second scheduling cell 207 can both be counted for the first scheduled cell 201. Therefore, a rule must be defined to allocate the PDCCH monitoring capability allowed in the first scheduled cell 201 (i.e., the maximum number of executable BD / CCEs) to the first scheduling cell 205 and the second scheduling cell 207, which complicates the terminal's PDCCH monitoring operation.

[0097] Therefore, in the first embodiment, since the first scheduled cell is the reference cell, not allowing simultaneous monitoring of multi-cell DCI and single-cell DCI from different cells can reduce complexity.

[0098] On the other hand, referring to Figure 3, the reference cell 213 of cell set 203 can be set to the second scheduled cell 211. That is, the number of BD / CCEs corresponding to multi-cell DCI monitoring in the first scheduling cell 205 is counted against the second scheduled cell 211, and the number of BD / CCEs corresponding to single-cell DCI monitoring in the second scheduling cell 207 can be counted only against the first scheduled cell 201. Therefore, from the perspective of PDCCH candidate mapping (or BD / CCE count) or DCI size counting of the first scheduled cell 201, it is equivalent to the case where the first scheduled cell 201 is scheduled only from the second scheduling cell 207. Therefore, the PDCCH monitoring capability allowed for the first scheduled cell 201 (i.e., the maximum number of executable BD / CCEs) can be fully performed by the second scheduled cell 207, and the terminal can perform PDCCH monitoring operations for the first scheduled cell 201 in a manner consistent with conventional methods.

[0099] This disclosure enables a terminal to perform PDCCH monitoring operations for scheduling a single serving cell (i.e., a scheduled cell) on multiple serving cells (i.e., scheduling cells) if certain conditions are met. The certain conditions may include at least one of the following: The multiple serving cells may include a first scheduling cell 205 and a second scheduling cell 207. The first scheduling cell 205 can schedule PDSCH / PUSCH to a scheduled cell based on a multi-cell DCI. The second scheduling cell 207 can schedule PDSCH / PUSCH to a scheduled cell based on a single-cell DCI. The scheduled cell may also be included in a cell set 203 corresponding to a multi-cell DCI, and the reference cell 213 of the cell set 203 may be set to another scheduled cell instead of a scheduled cell.

[0100] The conditions described above can correspond to the concept shown in the second embodiment of Figure 3. Conversely, if a scheduled cell is set as the reference cell of the cell set to which it belongs, the number of scheduling cells corresponding to that scheduled cell can be limited to a maximum of one. For example, if a scheduled cell considered to be a reference cell receives multi-cell scheduling from a first scheduling cell and single-cell scheduling from a second scheduling cell, the first and second scheduling cells can be the same cell. In one embodiment, a single scheduled cell can be a secondary cell. Also, a single scheduled cell can be a primary cell or a primary-secondary cell.

[0101] In other words, if a single serving cell is included in a cell set corresponding to a multi-cell DCI, and the reference cell of the cell set is set to another scheduled cell rather than the serving cell, then, as shown in Figure 3, since the first scheduled cell is not the reference cell, it is possible to reduce scheduling complexity by allowing simultaneous monitoring of multi-cell DCI and single-cell DCI from different cells.

[0102] [PDCCH Monitoring Operation] On the other hand, when carrier aggregation is configured on a terminal, the maximum number of BD / CCEs that each serving cell (i.e., each scheduled cell) terminal can perform can be determined based on the terminal's capabilities. A terminal can receive configurations for multiple serving cells (i.e., downlink cells) from a base station. PDCCH monitoring operations for scheduling each serving cell can be performed on the related scheduling cells or the downlink active bandwidth portion of the scheduling cells. When μ is the index representing the subcarrier interval set on a scheduling cell or the subcarrier interval of the downlink active bandwidth portion of the scheduling cell, the number of serving cells corresponding to the subcarrier interval setting μ is N cells μIt can be expressed as μ. μ can be assigned values of 0, 1, 2, 3, which can respectively correspond to subcarrier intervals of 15 kHz, 30 kHz, 60 kHz, 120 kHz, …. The total number of serving cells set in the terminal is sum_μ{N cells μ}, that is, it can be expressed as N cells 0 +N cells 1 + ….

[0103] The terminal can report N cap to the base station as PDCCH monitoring capability information (N cap is a natural number). According to one embodiment, when the number of serving cells sum_μ{N cells μ} does not exceed N cap , the terminal can perform a maximum of M max、slot、μ PDCCH blind decoding operations per slot of the corresponding scheduling cell for each serving cell, and can process a maximum of C max、slot、μ CCEs. M max、slot、μ and C max、slot、μ can respectively mean the upper limit values of the number of BDs and the number of CCEs for a single serving cell, and can be predefined in the technical standard. That is, in the above case, the terminal can perform PDCCH monitoring operations corresponding to the full capability for each serving cell.

[0104] According to other embodiments, when the number of serving cells sum_μ{N cells μ} exceeds N cap , the terminal can appropriately allocate the PDCCH monitoring capability limited by N cap by subcarrier interval. According to the first embodiment, the terminal has a maximum of M total、slot、μ =floor(N cap *M max、slot、μ *N cells μ / sum_μ{N cells μ}) Blind decoding operations can be performed, up to C total、slot、μ =floor(N cap *C max、slot、μ *N cells μ / sum_μ{N cells μ Channel estimation operations can be performed for}) CCEs. In addition, according to the second embodiment, the terminal can perform a maximum of min(M) for each scheduled cell. max、slot、μ M total、slot、μ ) number of blind decoding operations and maximum min(C max、slot、μ , C total、slot、μ ) CCE receiving operations can be performed. As a result, the maximum number of BD / CCEs that a terminal can monitor for each serving cell is M max、slot、μ and C max、slot、μ It can be even smaller.

[0105] In one embodiment, when a multi-TRP PDSCH transmission method is used, N cells μ The number of cells depends on whether a CORESET pool is set in each cell and / or the number of such pools. cell、0 μ N cells, and further enhanced PDCCH monitoring capabilities are applied. cell、1 μ It can be classified into N cells. cells μ =N cell、0 μ +N cell、1 μ The relationship can be established. When counting the number of serving cells using the method described above, N cell、1 μ The number of cells can be scaled by applying a multiplication coefficient of γ. For example, sum_μ{N cells μ} is sum_μ{N cell、0 μ +γ*N cell、1 μ} can be substituted. Similarly, floor(N cap *Mmax、slot、μ *N cells μ / sum_μ{N cells μ ) and floor(N cap *C max、slot、μ *N cells μ / sum_μ{N cells μ ) are respectively floor(N cap *M max、slot、μ *(N cell、0 μ + γ*N cell、1 μ ) / sum_μ{N cell、0 μ + γ*N cell、1 μ ) and floor(N cap *C max、slot、μ *(N cell、0 μ + γ*N cell、1 μ ) / sum_μ{N cell、0 μ + γ*N cell、1 μ ) can be substituted. γ can be a natural number. Or, γ can be a positive integer. For example, γ can be values such as 0.5, 1, 1.5, 2, etc., and can be set by the base station or predefined in the technical standard.

[0106] FIG. 4 shows a second embodiment of the single DCI multi-cell scheduling method according to an embodiment of the present disclosure.

[0107] Referring to Figure 4, Figure 4 shows that multi-cell scheduling can be performed based on the same configuration as the first embodiment in Figure 1. That is, multi-cell DCI can be used to perform multi-cell scheduling on a cell set 403 that includes a first scheduled cell 405, a second scheduled cell 407, and a third scheduled cell 409. Cell set 403 is a downlink cell set, and multi-cell scheduling can mean multi-cell PDSCH scheduling. Alternatively, cell set 403 is an uplink cell set, and multi-cell scheduling can mean multi-cell PUSCH scheduling. Alternatively, cell set 403 can mean both a downlink cell set and an uplink cell set. Multi-cell DCI can be monitored on a search space set mapped to the first scheduling cell. The search space set can be set for the first scheduled cell. That is, the first scheduled cell 405 can serve as a reference cell. The first scheduled cell 405 may or may not coincide with the first scheduling cell 401.

[0108] In one embodiment, the terminal can monitor the multi-cell DCI and the single-cell scheduling DCI for each scheduled cell (hereinafter referred to as "single-cell DCI"). In an NR communication system, the single-cell scheduling DCI may include downlink DCIs such as DCI formats 1_0, 1_1, 1_2, etc., and uplink DCIs such as DCI formats 0_0, 0_1, 0_2, etc.

[0109] Referring to Figure 4, the terminal can monitor both multi-cell DCI and single-cell DCI for the first scheduled cell 405. In one embodiment, since the first scheduled cell 405 is a reference cell, the multi-cell DCI monitoring operation and the single-cell DCI monitoring operation for the first scheduled cell 405 can only be performed on the same scheduling cell (e.g., the first scheduling cell 401).

[0110] In contrast, for the second scheduled cell 407 and the third scheduled cell 409, the terminal does not need to monitor the single-cell DCI. The base station does not need to set up a search space set (and CORESET) for the second scheduled cell 407 and the third scheduled cell 409 on the terminal. For example, the RRC serving cell configuration information for the second scheduled cell 407 and the third scheduled cell 409 does not need to include PDCCH configuration parameters (or IE (information element)). PDCCH configuration parameters (or IE) can include PDCCH configuration parameters for single-cell scheduling and / or PDCCH configuration parameters for multi-cell scheduling. Therefore, scheduling for the second scheduled cell 407 and the third scheduled cell 409 can depend only on the multi-cell DCI. The terminal does not need to perform PDCCH blind decoding and CCE channel estimation operations for the single-cell DCI for the second scheduled cell 407 and the third scheduled cell 409. In other words, the number of BD / CCEs for the second scheduled cell 407 and the third scheduled cell 409 relative to a single cell DCI may be 0. Also, the number of DCI formats that the terminal monitors for the second scheduled cell 407 and the third scheduled cell 409 relative to a single cell DCI may be 0. Hereinafter, the serving cell (e.g., the second scheduled cell 407, the third scheduled cell 409) may be referred to as the first serving cell.

[0111] The following describes the method for PDCCH monitoring operation in each serving cell when carrier aggregation including a first serving cell is applied to a terminal through the above description.

[0112] [First Method] According to an embodiment, when the subcarrier spacing setting of the cell that schedules the first serving cell is μ, the N cells μ value can be calculated by counting the first serving cell once. That is, the first serving cell can increase N cells μ by only 1. At the same time or separately, the sum_μ{N cells μ} value can be calculated by counting the first serving cell once. That is, the first serving cell can increase sum_μ{N cells μ} by only 1.

[0113] According to other embodiments, when a plurality of CORESET pools are set for the first serving cell, the first serving cell can be counted γ times in the cell number calculation formula (first method).

[0114] The first method can be interpreted as a method of allocating the PDCCH monitoring capability of the terminal to the first serving cell, although there is no PDCCH monitoring operation counted for the first serving cell. Although there may be drawbacks to this method, it will be described in detail below.

[0115] FIG. 5 is a conceptual diagram showing a third embodiment of a single DCI multi-cell scheduling method according to an embodiment of the present disclosure.

[0116] Referring to Figure 5, a carrier aggregate of six serving cells 503, 505, 509, 511, 513, and 515 can be configured on the terminal. The six serving cells 503, 505, 509, 511, 513, and 515 can be distinguished from each other by indices 0 to 5 (Cell0, Cell1, Cell2, Cell3, Cell4, and Cell5). In addition, two cell sets 517 and 519 can be configured for single DCI multi-cell scheduling. The first cell set 517 may include serving cells 0 and 1, and the second cell set 519 may include serving cells 2 to 5. The scheduling cell of the first cell set 517 may be set to serving cell 0 (511), and serving cell 0 may be considered the reference cell. The scheduling cell of the second cell set 519 may be set to serving cell 2 (507), and serving cell 2 may be considered the reference cell. Serving cell 0 (i.e., the downlink active bandwidth portion of serving cell 0) can follow a subcarrier interval setting μ0 (e.g., subcarrier interval of 15 kHz), and serving cell 2 (i.e., the downlink active bandwidth portion of serving cell 2) can follow a subcarrier interval setting μ1 (e.g., subcarrier interval of 30 kHz). For example, serving cell 0 is M max、slot、μ0 =44 and C max、slot、μ0 It may also be =56, and serving cell 1 is M max、slot、μ1 =44 and C max、slot、μ1 It may also be = 56. Furthermore, N is used for the terminal's PDCCH monitoring capability for carrier aggregation. cap It can be assumed that = 2.

[0117] Referring to Figure 5, single-cell scheduling does not need to be configured on the terminal. That is, PDSCH and / or PUSCH scheduling for the six serving cells can rely solely on multi-cell scheduling. The terminal can monitor the multi-cell DCI with the search space set up for serving cell 0 and serving cell 2, and based on the multi-cell DCI, PDSCH or PUSCH can be scheduled for one or more cells constituting the first cell set and one or more cells constituting the second cell set.

[0118] Referring to Figure 5, serving cell 1 (505) and serving cells 3-5 (511-515) satisfy the conditions for a first serving cell. That is, single-cell scheduling is not applied to serving cell 1 (505) and serving cells 3-5 (511-515), so the terminal does not perform single-cell DCI monitoring for the serving cells.

[0119] Furthermore, while serving cell 1 (505) can be multi-cell scheduled from serving cell 0 (501), the number of BD / CCEs and DCI sizes corresponding to the search space set for multi-cell scheduling are counted for serving cell 0, not for multiple serving cells.

[0120] Furthermore, while serving cells 3-5 can be multi-cell scheduled from serving cell 2, the number of BD / CCEs and DCI sizes corresponding to the search space set for multi-cell scheduling are counted against serving cell 2, not against multiple serving cells.

[0121] Consequently, the number of BD / CCEs corresponding to each serving cell 505, 511-515 may be 0. Also, the number of DCI formats corresponding to each serving cell 505, 511-515 may be 0.

[0122] In the first method, when a carrier aggregation including the first serving cell Cell1 or Cells3-5 is applied to the terminal, N is generated by each of the serving cells. cells μ Value and sum_μ{N cells μ The value can be increased by 1 (or γ). That is, each serving cell can be counted once (or γ times). In one embodiment, serving cell 0, which is the scheduling cell for serving cells 0 and 1, follows the subcarrier interval setting μ, so N cells μ0 It can be =2. Also, since serving cell 2, which is the scheduling cell for serving cells 2 to 5, follows the subcarrier interval setting μ1, N cells μ1 =4 is possible. Therefore, sum_μ{N cells μ} = 6 is possible. cap =2 sum_μ{N cells μ}>N cap Since this is true, the terminal sets the total maximum floor(N) for serving cells 0 and 1 corresponding to the subcarrier interval setting μ0. cap *M max、slot、μ0 *N cells μ0 / sum_μ{N cells μ}) = floor(2*44*2 / 6) = 29 blind decoding operations can be performed, up to floor(N cap *C max、slot、μ0 *N cells μ0 / sum_μ{N cells μ}) = floor(2 * 56 * 2 / 6) = 37 CCEs can be processed. Also, the terminal can process a maximum of min(M) for each of serving cells 0 and 1. max、slot、μ0、 M total、slot、μ0 ) = min(44, 29) = 29 blind decoding operations and maximum min(C max、slot、μ0 , C total、slot、μ0 ) = min(56, 37) = 37 CCEs can be processed.

[0123] Consequently, the maximum number of BDs and CCEs that a terminal can process for serving cell 0 is M max、slot、μ0 =44 and C max、slot、μ0 This is a decrease compared to =56, which can limit PDCCH monitoring and PDCCH transmission operations in serving cell 0. If serving cell 0 is the primary cell, the above problem may be relatively more serious. The terminal may omit BD / CCE counting for serving cell 1, and the BD / CCE capability allocated to serving cell 1 by the above calculation formula may be ignored.

[0124] [Second method] In another embodiment, when the subcarrier interval setting of the cell that schedules the first serving cell is μ, N cells μ The value may be the number of serving cells, excluding the first serving cell, among scheduled cells where the subcarrier interval setting of the scheduling cell is μ. That is, N cells μ In terms of values, the first serving cell does not need to be counted. Simultaneously or separately, sum_μ{N cells μ The value can be the number of serving cells among the scheduled cells, excluding the first serving cell. That is, sum_μ{N cells μ In the} value, the first serving cell does not need to be counted (second method).

[0125] The embodiment shown in Figure 5 can be to which the second method described above is applied. According to the second method, N cells μ Value and sum_μ{N cells μThe value can be increased by 1 (or γ) by serving cell 0 (501) and serving cell 2 (507). That is, each serving cell may be counted once (or γ times). In contrast, serving cell 1 (505) and serving cells 3-5 (511-515) may not be counted. According to the second method, only serving cell 0 can be considered a scheduled cell for the subcarrier interval setting μ0, and the corresponding N cells μ0 The value can be 1. Also, only serving cell 2 can be considered a scheduled cell for the subcarrier interval setting μ, and the corresponding N cells μ1 The value can be 1.

[0126] Therefore, sum_μ{N cells μ} can be 2. In this case, sum_μ{N cells μ}=N cap Therefore, the maximum number of BDs and the maximum number of CCEs for serving cell 0 are M, respectively. max、slot、μ0 =44 and C max、slot、μ0 It can be determined that the value is 56.

[0127] As a result, it can be confirmed that there is no limit to the maximum number of BDs and CCEs that a terminal can process for serving cell 0. In other words, the shortcomings of the first method can be overcome by applying the second method.

[0128] The second method can be interpreted as not allocating the total number of BD / CCEs that the terminal can process in a unit of time (e.g., one slot) to the first serving cells (Cell 1 (505), and Cells 3-5 (511-515)). When the terminal counts the total number of carriers (e.g., total number of carriers per subcarrier interval) for the purpose of determining the number of BD / CCEs per cell, it may exclude (i.e., not count) the first serving cells. The upper limit of the number of BD / CCEs per serving cell that is ultimately determined may be the same as if the terminal did not have a first serving cell configured.

[0129] As a result, the BD / CCE capability that a terminal can perform in serving cells other than the first serving cell, i.e., the upper limit of the number of BD / CCEs, can be increased compared to the result obtained by applying Method 1.

[0130] As described above, the predetermined conditions for applying the above embodiments may include at least one of the following: no search space set (e.g., PDCCH setting IE, search space set setting IE) is set for the first serving cell (or scheduling of the first serving cell); the number of BDs for the first serving cell is 0; the number of CCEs for the first serving cell is 0; or the number of DCI format sizes monitored by the first serving cell is 0.

[0131] The first serving cell must be any one scheduled cell belonging to the cell set that is not set as the reference cell. Any scheduled cell belonging to the cell set that is not the reference cell can be considered the first serving cell if it satisfies the above conditions. The first serving cell may be the cell from which a terminal sends a PUCCH. For example, the first serving cell may send a HARQ-ACK for a PDSCH scheduled to the cell set to which the first serving cell belongs. HARQ-ACKs for PDSCHs scheduled by the same multi-cell DCI may be transmitted using the same PUCCH resource.

[0132] In one embodiment, the set of search spaces monitored by a terminal in a scheduling cell performing multi-cell scheduling can form a search space set group (SSSG). Multiple SSSGs can be set in the first scheduling cell, and each set of search spaces set up to monitor the multi-cell DCI can be included in any one of the SSSGs.

[0133] Furthermore, the terminal can be instructed by the base station to perform an SSSG switching operation, and based on this instruction, the terminal can refrain from performing a search space set monitoring operation for the multi-cell DCI for a certain period of time. The time period may include a period of monitoring an SSSG to which the search space set does not belong. The timer for the SSSG can operate during the monitoring period. When the timer expires, the terminal can perform a switching operation to a pre-configured SSSG or a default SSSG. The terminal can also be dynamically instructed by the base station to perform a PDCCH monitoring skip operation. During the PDCCH monitoring skip period, the terminal can skip the PDCCH monitoring operation for the search space set configured to monitor the multi-cell DCI. The SSSG switching operation or the PDCCH monitoring skip operation may be instructed by a group common DCI (e.g., DCI format 2_0) or a scheduling DCI. The SSSG switching operation or the PDCCH monitoring skip operation may also be instructed by a multi-cell DCI. That is, the multi-cell DCI may include SSSG switching instruction information and / or PDCCH monitoring skip instruction information. SSSG switching or PDCCH monitoring omission operation can be applied to scheduling cells and can operate independently of scheduled cells.

[0134] [HARQ-ACK Feedback Method] A terminal can feed back a HARQ-ACK, which is a reception response of a PDSCH scheduled by multi-cell DCI, to the base station, which can then decide whether or not to retransmit the PDSCH of the TB based on the feedback. If the terminal successfully receives the PDSCH (or the TB), the HARQ-ACK information corresponding to the TB may be an ACK. Conversely, if the terminal does not successfully receive the PDSCH (or the TB), the HARQ-ACK information corresponding to the TB may be a NACK (negative ACK). The HARQ-ACK information may contain only an ACK or only a NACK, or it may contain either an ACK or a NACK. The HARQ-ACK information corresponding to each downlink TB may be 1 bit.

[0135] When the CBG (code block group)-based HARQ transmission scheme is used, a single TB can consist of N CBGs, and each downlink TB can be associated with N bits of HARQ-ACK information (where N is a natural number).

[0136] In one embodiment, HARQ-ACK information can be reported to a base station in a HARQ-ACK codebook. HARQ-ACK codebooks include HARQ-ACK codebooks with a semi-fixed size (hereinafter referred to as "Type 1 HARQ-ACK codebook"), HARQ-ACK codebooks with a dynamically variable size (hereinafter referred to as "Type 2 HARQ-ACK codebook"), and HARQ-ACK codebooks for simultaneously feeding back HARQ-ACKs to multiple downlink HARQ processes (hereinafter referred to as "Type 3 HARQ-ACK codebook"). Each bit constituting the payload of the HARQ-ACK codebook can be mapped to each downlink HARQ-ACK. The HARQ-ACK codebook can be transmitted to the base station via an uplink signal or channel (e.g., PUCCH, PUSCH, SRS, etc.).

[0137] According to one embodiment, a terminal can monitor both multi-cell DCI format and single-cell DCI format simultaneously (or all of them). The serving cells that the terminal monitors for multi-cell DCI format and the serving cells that the terminal monitors for single-cell DCI format may be the same or different, and the serving cells may belong to the same PUCCH group (or PUCCH cell group). That is, HARQ-ACKs of PDSCH scheduled by multi-cell DCI format and HARQ-ACKs of PDSCH scheduled by single-cell DCI format can be reported to the base station via the same serving cell (e.g., PUCCH cell). A terminal can schedule a PDSCH (or PDSCH repetitive transmission) to a single serving cell by single-cell DCI. Alternatively, a terminal can schedule a PDSCH (or PDSCH repetitive transmission) to one or more serving cells by multi-cell DCI. The number of TBs contained in each PDSCH can be determined based on the transmission operation in each serving cell. For example, a PDSCH with a MIMO (multiple-input multiple output) transmission layer count scheduled to be below a certain threshold can contain a single TB, while a PDSCH with a MIMO transmission layer count scheduled to be above a certain threshold can contain two TBs.

[0138] In one embodiment, a terminal can report a PDSCH HARQ-ACK to a base station based on a Type 2 HARQ-ACK codebook. In this case, HARQ-ACKs of all PDSCHs scheduled simultaneously by multi-cell DCI can be included in the same HARQ-ACK codebook. For example, the HARQ-ACK of a PDSCH scheduled in a first scheduled cell and the HARQ-ACK of a PDSCH scheduled in a second scheduled cell can be included in the same Type 2 HARQ-ACK codebook and transmitted to the base station via the same PUCCH resource (e.g., the same PUCCH resource in the same serving cell). A more specific method is described below.

[0139] [1st method] As a first method, a single Type 2 HARQ-ACK codebook can contain all HARQ-ACKs of PDSCHs scheduled by multi-cell DCI and all HARQ-ACKs of PDSCHs scheduled by single-cell DCI. A terminal can include all downlink HARQ-ACKs with the same transmission timing (e.g., transmit slot, transmit subslot) in the same codebook, regardless of the DCI format used for scheduling, and can report the codebook to the base station at the said timing. The DAI (downlink assignment index) can also be unified for both multi-cell DCI and single-cell DCI. Each DCI can occupy a fixed number of bits (e.g., C bits) in the Type 2 HARQ-ACK codebook. The value of C can be determined as the maximum number of TBs that can be scheduled in a single DCI transmission. For example, in the second embodiment, a multi-cell DCI can schedule up to three cells simultaneously. Assuming that each PDSCH in each scheduled cell contains a single TB, a terminal can schedule up to three TBs in a single scheduling. Therefore, C can be determined to be 3. If the number of TBs actually scheduled by DCI is less than C, the HARQ-ACK corresponding to the TB can be mapped to some of the C bits, and the remaining bits can be set to a predefined value (e.g., 0 or 1, ACK or NACK).

[0140] [Second method] Secondly, multiple subcodebooks can be defined for a type 2 HARQ-ACK codebook. These subcodebooks may include a first subcodebook and a second subcodebook. The DAI can operate (i.e., be counted) independently for each subcodebook. The terminal can map the HARQ-ACK corresponding to each DCI to one of the first and second subcodebooks, based on the number of serving cells scheduled by the single DCI. In the case of single-cell PDSCH scheduling, i.e., when a PDSCH is scheduled for only one serving cell by the DCI, the corresponding HARQ-ACK can be mapped to the first subcodebook. In contrast, in the case of multi-cell PDSCH scheduling, i.e., when a PDSCH is scheduled for two or more cells by a multi-cell DCI format, the corresponding HARQ-ACK can be mapped to the second subcodebook.

[0141] The number of bits in the HARQ-ACK codebook payload assigned to each DCI may be fixed, regardless of the number of HARQ-ACKs corresponding to each DCI. In this case, the number of bits can be set to different values ​​between the first subcodebook and the second subcodebook. One C1 bit can be assigned to each DCI corresponding to the first subcodebook, and two C2 bits can be assigned to each DCI corresponding to the second subcodebook. In one embodiment, since the first subcodebook combines HARQ-ACKs for single-cell scheduling, the maximum number of TBs that can be scheduled by each DCI transmission may be two. Therefore, the C1 value can be determined to be either 1 or 2. In this case, the same C1 value can be applied to both the single-cell DCI format and the multi-cell DCI format. That is, single-cell PDSCH scheduling using the single-cell DCI format and single-cell PDSCH scheduling using the multi-cell DCI format can each occupy one C1 bit in the first subcodebook.

[0142] In one embodiment, C1 = 2. That is, in at least one scheduled cell, the terminal can be configured to receive up to two TBs via one PDSCH. In this case, two bits can be allocated in the first subcodebook for the HARQ-ACK of a PDSCH scheduled by a single-cell DCI, and the HARQ-ACK can be mapped to at least a portion of the two bits. Furthermore, two bits can also be allocated in the first subcodebook for the HARQ-ACK of a PDSCH scheduled to a single serving cell by a multi-cell DCI, and the HARQ-ACK can be mapped to at least a portion of the two bits.

[0143] On the other hand, the second subcodebook combines HARQ-ACK with multi-cell scheduling, so the C2 value can be determined to the maximum number of TBs that can be scheduled at once by the multi-cell DCI. For example, if the cell set includes a first serving cell and a second serving cell, and the terminal can schedule a maximum of one TB via one PDSCH in the first serving cell and a maximum of two TBs via one PDSCH in the second serving cell, then the C2 value can be determined to 3 (=1+2), which is the maximum number of TBs that can be scheduled simultaneously.

[0144] In general, C2 can have a larger value than C1. C1 and C2 can be fixedly applied to all DCIs within each subcodebook, regardless of the number of TBs actually scheduled by the DCI. In this case, when a multi-cell DCI schedules a single serving cell, the corresponding HARQ-ACK can be included in and transmitted within the first subcodebook, and the size of the HARQ-ACK codebook payload occupied by the DCI can be reduced from C2 to C1. Thus, UCI overhead can be reduced.

[0145] In one embodiment, PDSCHs scheduled for a terminal may be dropped. This means that the number of serving cells scheduled by DCI does not have to match the number of serving cells in which the terminal actually performs PDSCH reception operations. For example, a multi-cell DCI may schedule a PDSCH to each of two serving cells, and the terminal can perform PDSCH reception operations on only one of the two serving cells. That is, the number of cells scheduled by DCI may be 2, while the number of cells in which the terminal actually receives a PDSCH may be 1. Alternatively, all PDSCHs scheduled by DCI may be dropped, and the number of cells in which the terminal actually receives a PDSCH may be 0. In this case, the terminal can determine the subcodebook to which the DCI is mapped based on the nominal number of cells scheduled by DCI, rather than the number of cells in which it actually performs reception operations. For example, regardless of the number of cells in which the terminal actually received the PDSCH, the DCI scheduled two serving cells, so the HARQ-ACK corresponding to the DCI can be mapped to the second subcodebook.

[0146] [3rd method] A third method involves using the multiple subcodebooks described above, but classifying the HARQ-ACKs corresponding to each DCI into one of the first or second subcodebooks based on the format of the received DCI. That is, HARQ-ACKs for PDSCHs scheduled using a single-cell DCI format can be included in the first subcodebook, while HARQ-ACKs for PDSCHs scheduled using a multi-cell DCI format can be included in the second subcodebook.

[0147] According to the third method, the HARQ-ACK corresponding to the multi-cell DCI can always be included in the second subcodebook, regardless of the number of cells scheduled by the multi-cell DCI, i.e., the size of the scheduled cell set.

[0148] The terminal can generate a first subcodebook and a second subcodebook according to the rules described above, and can concatenate the first and second subcodebooks to form a type 2 HARQ-ACK codebook. Each subcodebook can also be constructed in the same way as the type 2 HARQ-ACK codebook. Consequently, the first and second subcodebooks can be transmitted over the same uplink resource (e.g., PUCCH, PUSCH).

[0149] At a given HARQ-ACK feedback point, all HARQ-ACKs may be mapped to a first subcodebook according to the criteria described above, or all HARQ-ACKs may be mapped to a second subcodebook according to the criteria described above. In this case, a type 2 HARQ-ACK codebook may contain only one of the first and second subcodebooks. Furthermore, the transmission time (e.g., transmission slot) of the type 2 HARQ-ACK codebook may coincide with the transmission time (e.g., transmission slot) of the HARQ-ACK to the SPS PDSCH. In this case, the first subcodebook and / or the second subcodebook may constitute a type 2 HARQ-ACK codebook together with the HARQ-ACK to the SPS PDSCH. The bit positions to which the HARQ-ACK of the SPS PDSCH is mapped may be determined by a predefined rule. For example, in the second HARQ-ACK codebook, the first subcodebook and / or the second subcodebook can be mapped first, followed by the HARQ-ACK of the SPS PDSCH.

[0150] One embodiment can also be applied when multiple cell sets are configured on a terminal. For example, a terminal can perform HARQ-ACK feedback operation based on the two subcodebooks described above, regardless of the number of configured cell sets. According to the second method described above, if a multi-cell DCI schedules two or more cells, regardless of the cell sets it schedules, the HARQ-ACK of the PDSCH scheduled by the multi-cell DCI can be mapped to the second subcodebook. Also, according to the third method, if a PDSCH is scheduled by the multi-cell DCI format, regardless of the cell sets it schedules, the HARQ-ACK of the PDSCH can be mapped to the second subcodebook. Multiple cell sets can belong to the same PUCCH group (i.e., a set of downlink cells in which the PUCCH transmission cell is the same).

[0151] Similarly, the C2 value can be determined by the maximum number of TBs that can be scheduled at once by the multi-cell DCI. For example, if the maximum number of TBs that can be scheduled simultaneously by the multi-cell DCI in the first cell set is C21, and the maximum number of TBs that can be scheduled simultaneously by the multi-cell DCI in the second cell set is C2, then the C2 value can be determined as max(C21, C22). The terminal can map the HARQ-ACK of downlink TBs scheduled by each multi-cell DCI to C2 bits (or a portion of C2 bits) of the second subcodebook, regardless of the cell set that the multi-cell DCI is scheduling. In this case, the DAI can be a unified count for multiple cell sets. That is, the DAI can be information that instructs the terminal on the number and index of multi-cell scheduling DCIs (or multi-cell DCI formats) transmitted to the terminal for all cell sets configured on the terminal.

[0152] As in other examples, the number of bits in the second subcodebook occupied by a multi-cell DCI (i.e., its corresponding HARQ-ACK) can be determined by the set of cells scheduled by the multi-cell DCI. If C21 is the maximum number of TBs that can be simultaneously scheduled by the multi-cell DCI in the first set of cells, and C22 is the maximum number of TBs that can be simultaneously scheduled by the multi-cell DCI in the second set of cells, then the terminal can map the HARQ-ACK of a downlink TB scheduled by the multi-cell scheduling DCI (or multi-cell DCI format) scheduling the first set of cells to C21 bits (or a portion of C21 bits) in the first subcodebook, and map the HARQ-ACK of a downlink TB scheduled by the multi-cell scheduling DCI (or multi-cell DCI format) scheduling the second set of cells to C22 bits (or a portion of C22 bits) in the second subcodebook. In this case, the DAI can be counted within each cell set for each set. In other words, DAI can be information that instructs the terminal on the number and index of the multi-cell scheduling DCI (or multi-cell DCI format) transmitted to the terminal for each cell set configured on the terminal.

[0153] [4th method] By the fourth method, HARQ-ACKs corresponding to multi-cell scheduling DCIs (or multi-cell DCI formats) that schedule different sets of cells can be mapped to different subcodebooks. For example, a HARQ-ACK for a TB scheduled for a first set of cells can be mapped to a second subcodebook, and a HARQ-ACK for a TB scheduled for a second set of cells can be mapped to a third subcodebook. The first subcodebook can still contain HARQ-ACKs for TBs scheduled by a single-cell scheduling DCI (or single-cell DCI format). The terminal can map the HARQ-ACK of a downlink TB scheduled by the multi-cell scheduling DCI (or multi-cell DCI format) that schedules the first cell set to C21 bits (or a portion of C21 bits) in the second subcodebook, and can map the HARQ-ACK of a downlink TB scheduled by the multi-cell scheduling DCI (or multi-cell DCI format) that schedules the second cell set to C22 bits (or a portion of C22 bits) in the third subcodebook. Similarly, the DAI (downlink assignment index) can be counted within each cell set for each cell set.

[0154] As described above, in one embodiment, the number of FDRA fields included in a multi-cell DCI can be fixed to the same number as the size of the cell set. Alternatively, if a multi-cell DCI has one FDRA field, and that one FDRA field is composed of multiple blocks, the number of blocks can be fixed to the same number as the size of the cell set. Furthermore, the number of fields (or corresponding blocks) that indicate other scheduling information (e.g., MCS (modulation and coding scheme), NDI (new data indicator), RV (redundancy version), HARQ process number, etc.) can be fixed to the same number as the size of the cell set. In this case, whether or not a scheduled cell belonging to the cell set is scheduled can be indicated by the field value of the field corresponding to the scheduled cell. For example, if an FDRA field (or corresponding block within the field) in a multi-cell DCI is set to a specific code point, the terminal can consider that the cell corresponding to the FDRA field (or corresponding block within the field) is not scheduled by the multi-cell DCI. At this time, other fields corresponding to cells that are not scheduled (e.g., fields indicating MCS, NDI, RV, HARQ process number, etc.) can be used for other purposes. For example, the fields can be used to indicate the dormancy / non-dormancy operating state of SCells (secondary cell(s)) set on the terminal. The terminal can omit the remaining transmit / receive operations except for certain operations (e.g., downlink measurement operations) in SCells that have been instructed to perform dormancy operations by the multi-cell DCI. The terminal can perform bandwidth partial switching operations in SCells that have been instructed to perform dormancy operations. For example, the terminal can switch to a dormant bandwidth portion and activate a dormant bandwidth portion. In a dormant bandwidth portion, the terminal can omit PDCCH monitoring operations.

[0155] In one embodiment, in multi-cell scheduling, the number of scheduled cells not scheduled by multi-cell DCI may be two or more. For example, the first scheduled cell may be scheduled by multi-cell DCI, while the second and third scheduled cells may not be scheduled. In this case, the FDRA field corresponding to the first scheduled cell can indicate the frequency domain resource allocation information of the PDSCH scheduled to the first scheduled cell. In contrast, the FDRA fields corresponding to the second and third scheduled cells can be set to specific code points (e.g., a bit sequence where all bits are 0, or a bit sequence where all bits are 1). In this case, other fields corresponding to the second and third scheduled cells (e.g., fields indicating MCS, NDI, RV, HARQ process number, etc.) may not be used for PDSCH scheduling. Other fields corresponding to the second and third scheduled cells can be used for other purposes. For example, a base station can use these fields to instruct a terminal to operate SCell in a dormant or non-dormant state. Furthermore, in one embodiment, the multi-cell DCI does not need to schedule a PDSCH or PUSCH for any serving cell belonging to the cell set. In this case, all FDRA fields (or all blocks of FDRA fields) of the multi-cell DCI may be set to specific code points (e.g., bit sequences where all bits are 0, bit sequences where all bits are 1). All FDRA fields of the multi-cell DCI can be used for the purposes described above.

[0156] More specifically, in one embodiment, the SCell sleep / non-sleep operating state can be indicated by a field corresponding to any one of several unscheduled cells. That is, any one cell can be determined based on the serving cell index. For example, the field corresponding to the cell with the smallest (or largest) serving cell index among the unscheduled cells can be used to indicate SCell sleep. Alternatively, the field corresponding to the cell with the largest serving cell index among the unscheduled cells can also be used to indicate SCell sleep.

[0157] In other embodiments, any one of the aforementioned cells can be determined by other priority rules that are not based on the serving cell index. These other priority rules can be set from the base station to the terminal or predefined in a technical standard.

[0158] In another embodiment, any one of the aforementioned cells can be instructed by the base station to the terminal. For example, the field used for SCell sleep instruction can be determined based on other fields (or other information) included in the multi-cell DCI. For example, the other field may be an FDRA field. The terminal can consider any of the serving cells corresponding to an FDRA (or the block of the FDRA field) if all the bits of a certain FDRA field (or a block of the FDRA field) are either 0 or all 1. If there are two or more serving cells where all the bits of the corresponding FDRA field (or a corresponding block of the FDRA field) are either 0 or all 1, then one of the multiple serving cells can be determined to be any one of the cells by the rules described above or by a setting from the base station.

[0159] In one embodiment, the priority between serving cells can be determined based on whether or not a serving cell is set as a reference cell. For example, a serving cell set as a reference cell may be given a higher (or lower) priority than other serving cells.

[0160] Of the fields constituting the multi-cell DCI format, at least one of the MCS field, NDI field, RV field, HARQ process number field, antenna port indicator field, or field indicating information about the DM-RS sequence corresponding to any one determined cell can be used to indicate the dormant or non-dormant behavior of the SCell set on the terminal. SCell dormancy indication can be made on a per-SCell group basis. A multi-cell DCI may contain SCell dormancy / non-dormancy indication information for one or more SCell groups, and this SCell dormancy / non-dormancy indication information can be mapped to a bit sequence consisting of at least one field and transmitted to the terminal.

[0161] At this time, among the serving cells belonging to the cell set, PDSCH can be assigned by multi-cell DCI to any serving cell other than the one mentioned above. The base station can schedule PDSCH to the first serving cell based on single multi-cell DCI and instruct the second serving cell to perform SCell sleep / non-sleep operation. The first serving cell may be any one cell belonging to the cell set scheduled by multi-cell DCI, and the second serving cell may or may not belong to the cell set. In this case, if the instruction information for the second serving cell is information instructing sleep operation, the first serving cell may be a different cell from the second serving cell. That is, a terminal does not have to expect to be instructed to enter / maintain a serving cell in a sleep state via single multi-cell DCI, while simultaneously being scheduled to receive a PDSCH or transmit a PUSCH in the serving cell. If the first and second serving cells are the same, the sleep instruction and scheduling instruction for the same serving cell can be contradictory, which can be considered an error. Furthermore, this also applies when a bit sequence in a multi-cell DCI is deemed not to actually map to the defined bit sequence, and the bit sequence is therefore held or reserved.

[0162] In the first embodiment, SCell dormancy / non-dormancy operation can be applied only when the multi-cell DCI satisfies certain conditions. For example, if the multi-cell DCI schedules only a specific single cell, the SCell dormancy / non-dormancy operation can be instructed by the multi-cell DCI. The specific single cell may be the cell on which the multi-cell DCI is transmitted (i.e., the scheduling cell). Simultaneously or separately, the specific single cell may be a PCell (or PSCell). That is, if the cell set includes a PCell, the cell set is multi-cell scheduled by PCells, and the multi-cell DCI schedules only PCells, the SCell dormancy / non-dormancy instruction method by the multi-cell DCI can be used.

[0163] Alternatively, according to the second embodiment, a specific single cell included in the cell set may be a reference cell. Furthermore, the terminal can expect to receive a multi-cell DCI containing SCell dormancy instruction information in the manner described above, but only when the serving cell on which the multi-cell DCI is transmitted belongs to the DRX activity time, and can perform the corresponding PDCCH monitoring operation and SCell dormancy / non-dormancy switching / maintenance operation.

[0164] In the third embodiment, if a scheduled cell indicator is present in the multi-cell DCI, SCell dormancy / non-dormancy operation can be instructed by the multi-cell DCI. However, when a scheduled cell is instructed by a scheduled cell indicator, the number of FDRA fields or blocks can be variable, making the above method difficult to apply. For this reason, the above-described method of instructing SCell dormancy / non-dormancy using a multi-cell DCI can be used restrictively when a scheduled cell indicator is not present in the multi-cell DCI.

[0165] In the fourth embodiment, if a multi-cell DCI schedules all cells in a cell set except for one cell, the SCell sleep / non-sleep operation can be instructed by the multi-cell DCI.

[0166] According to the fifth embodiment, SCell dormancy / non-dormancy behavior can be used when the CRC of a multi-cell DCI is scrambled with a specific RNTI. For example, the specific RNTI could be C-RNTI. If the multi-cell DCI is scrambled with another RNTI other than C-RNTI, such as CS-RNTI, the terminal can expect that the multi-cell DCI will either include a separate field for SCell dormancy indication or will not include SCell dormancy indication information.

[0167] The maximum number of MIMO layers that can be transmitted in a serving cell can be set to a threshold value or higher. For example, the threshold value may be 5. In this case, the PDSCH (or PUSCH) transmitted in the serving cell can contain a maximum of X TBs. In one embodiment, X may be 2. A serving cell can be included in a cell set for multi-cell scheduling. In this case, the multi-cell DCI can contain at least a portion of the scheduling information for the serving cell, such as the MCS field, NDI field, RV field, HARQ process number field, etc., up to a maximum of X TBs. The maximum number of TBs can be set to different values ​​among the serving cells belonging to the cell set. For example, the first serving cell and the second serving cell belonging to the cell set may correspond to X=1 and X=2, respectively. In this case, if a serving cell corresponding to X>1 is not scheduled by a certain multi-cell DCI, and SCell sleep / non-sleep operation is instructed via the field corresponding to the serving cell in the manner described above, the SCell sleep / non-sleep instruction information can be mapped to bits (sequences) corresponding to a specific TB (e.g., the first TB) in the field. In one embodiment, the SCell sleep / non-sleep instruction information can also be mapped to bit sequences corresponding to one or more TBs in the field.

[0168] If a set of cells contains two or more cells that are not scheduled by multi-cell DCI, each of the fields corresponding to the multiple unscheduled cells can be used for a different purpose. For example, the MCS field, NDI field, RV field, HARQ process number field, antenna port indicator field, and field indicating information about the DM-RS sequence corresponding to the first serving cell, which is an unscheduled cell, can be used for the first purpose, while at the same time, the MCS field, NDI field, RV field, HARQ process number field, antenna port indicator field, and field indicating information about the DM-RS sequence corresponding to the second serving cell, which is an unscheduled cell, can be used for the second purpose. The first purpose is one of the following uses: SCell sleep indicator, TCI (transmission configuration indicator) indicator (or QCL (quasi co-location) information indicator), CSI (channel state information) reporting triggering, SRS (sounding reference signal) transmission triggering, etc., and the second purpose may be one of the above uses other than the first purpose.

[0169] Figure 6 illustrates how the terminal operates according to one embodiment of the present disclosure.

[0170] Referring to Figure 6, the terminal can receive configuration information from the base station (BS) (601).

[0171] Based on configuration information, the terminal can designate multiple serving cells, including a first serving cell and a second serving cell, as a cell group (603).

[0172] The terminal can perform PDCCH monitoring operations to receive downlink control information (DCI) for scheduling cell groups in the PDCCH (physical downlink control channel) search space set (605).

[0173] In one embodiment, the PDCCH monitoring operation includes L PDCCH blind decoding operations, where L PDCCH blind decoding operations are counted only for scheduling the first serving cell (where N and L are positive integers).

[0174] Furthermore, in one embodiment, L PDCCH blind decoding operations can be counted as 0 for scheduling the second serving cell, and the second serving cell can be excluded from the number of scheduled cells (#).

[0175] In one embodiment, at least one of the configuration information of the PDCCH search space set is set in the first serving cell, and the PDCCH search space set for the second serving cell only does not need to be set in the terminal.

[0176] In one embodiment, the total number of PDCCH blind decoding operations performed by the terminal for scheduling the first serving cell is determined by the number of scheduled cells, and the number of scheduled cells can be counted by the subcarrier interval of the scheduling cell.

[0177] The terminal can receive DCI from the base station based on PDCCH monitoring operation (607).

[0178] In one embodiment, the DCI is received from a third serving cell belonging to the base station, and the third serving cell does not have to be the second serving cell.

[0179] In one embodiment, the serving cells scheduled by the DCI are indicated by a first field of the DCI, and the time domain resource allocation field of the DCI may include information indicating an entry in the RRC (radio resource control) setting table for each of the scheduled serving cells. Furthermore, the number of information blocks constituting the second field of the DCI can be determined by the number of scheduled serving cells.

[0180] In one embodiment, the first field can be mapped to a fixed position within the DCI payload.

[0181] In one embodiment, a PDCCH monitoring omission interval is indicated to the terminal based on DCI, and the PDCCH search space set does not need to be monitored by the terminal during the indicated omission interval.

[0182] The terminal can identify scheduling information for N serving cells belonging to a cell group (609).

[0183] Based on scheduling information, the terminal can receive data channels in at least one of the N serving cells (611).

[0184] In one embodiment, if at least one information block constituting a frequency domain resource allocation field is set to a specific code point, the terminal can perform an action to identify that at least one serving cell corresponding to at least one information block is not scheduled by the DCI.

[0185] In one embodiment, the frequency domain resource allocation field is included in the DCI, and at least one serving cell may be included in the cell group.

[0186] In one embodiment, the terminal is instructed whether or not to activate the dormant bandwidth portion in a secondary cell configured on the terminal, based on the field group corresponding to the serving cell with the lowest serving cell index among at least one serving cell identified as not being scheduled, and the field group may be included in the DCI.

[0187] In one embodiment, the secondary cell does not have to be included in the N serving cells.

[0188] Figure 7 shows a method for operating a base station according to one embodiment of the present disclosure.

[0189] Referring to Figure 7, the base station can transmit configuration information to the terminal (user equipment, UE) (701). In one embodiment, the base station may include a plurality of serving cells, including a first serving cell and a second serving cell.

[0190] The base station can transmit downlink control information (DCI) to the terminal (703).

[0191] In one embodiment, the DCI is transmitted from a third serving cell belonging to the base station, and the third serving cell does not have to be the second serving cell.

[0192] In one embodiment, the serving cell scheduled by the DCI can be indicated by the first field of the DCI.

[0193] Furthermore, in one embodiment, the time domain resource allocation field of the DCI may include information indicating an entry in the RRC (radio resource control) configuration table for each scheduled serving cell, and the number of information blocks constituting the second field of the DCI may be determined by the number of scheduled serving cells.

[0194] In one embodiment, the first field can be mapped to a fixed position within the DCI payload.

[0195] The base station can transmit at least one data channel based on scheduling information for N serving cells included in the DCI (where N is a positive integer) (705).

[0196] In one embodiment, a plurality of serving cells are identified as a cell group based on the configuration information, and the plurality of serving cells can include the N serving cells.

[0197] Figure 8 shows a configuration diagram of a terminal in a wireless communication system according to various embodiments of the present disclosure. The configuration illustrated in Figure 8 can be understood as a terminal configuration. The terms "...unit," "...period," etc. used herein mean a unit that processes at least one function or operation, which can be realized in hardware, software, or a combination of hardware and software.

[0198] Referring to Figure 8, the terminal may include a communication unit 810, a storage unit 820, and a control unit 830.

[0199] The communication unit 810 can perform functions for transmitting and receiving signals via a wireless channel. For example, the communication unit 810 can perform conversion functions between baseband signals and bit sequences according to the system's physical hierarchy standard. For example, during data transmission, the communication unit 810 can generate complex symbols by encoding and modulating the transmitted bit sequence. During data reception, the communication unit 810 can restore the received bit sequence by demodulating and decoding the baseband signal. The communication unit 810 can also upconvert the baseband signal to an RF band signal and transmit it via an antenna, and downconvert the RF band signal received via the antenna back to a baseband signal. For example, the communication unit 810 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and so on.

[0200] Furthermore, the communication unit 810 may include a number of transmit and receive paths. Additionally, the communication unit 810 may include at least one antenna array composed of a number of antenna elements. In terms of hardware, the communication unit 810 can consist of digital and analog circuits (e.g., an RFIC (radio frequency integrated circuit)). Here, the digital and analog circuits can be implemented as a single package. The communication unit 810 may also include a number of RF chains. Furthermore, the communication unit 810 can perform beamforming.

[0201] As described above, the communication unit 810 transmits and receives signals. Therefore, all or part of the communication unit 810 may be referred to as the "transmitter," "receiver," or "transceiver." Furthermore, in the following description, transmission and reception via the wireless channel can be used to include the processing performed by the communication unit 810 as described above.

[0202] The storage unit 820 can store data such as basic programs, application programs, and configuration information for the operation of the terminal. The storage unit 820 can be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. The storage unit 820 can then provide the stored data in response to a request from the control unit 830.

[0203] The control unit 830 can control the overall operation of the terminal. For example, the control unit 830 can transmit and receive signals via the communication unit 810. The control unit 830 can also write and read data from the storage unit 820. The control unit 830 can perform the functions of the protocol stack required by the communication standard. For this purpose, the control unit 830 may include or be part of at least one processor or microprocessor. Furthermore, part of the communication unit 810 and the control unit 830 may be referred to as a CP (communication processor).

[0204] Through various embodiments, the control unit 830 can be controlled to perform the various operations performed by the aforementioned terminal.

[0205] Figure 9 shows a diagram of a base station configuration in a wireless communication system according to various embodiments of the present disclosure. The configuration illustrated in Figure 9 can be understood as a base station configuration. The terms "...unit" and "...device" used below refer to a unit that processes at least one function or operation, which can be implemented in hardware, software, or a combination of hardware and software.

[0206] Referring to Figure 9, the base station may include a wireless communication unit 910, a backhaul communication unit 920, a storage unit 930, and a control unit 940.

[0207] The wireless communication unit 910 can transmit and receive wireless signals via a wireless channel. For example, the wireless communication unit 910 can perform conversion functions between baseband signals and bit sequences according to the system's physical layer standard. Also, when transmitting data, the wireless communication unit 910 can generate complex symbols by encoding and modulating the transmitted bit sequence. When receiving data, the wireless communication unit 910 can reconstruct the received bit sequence by demodulating and decoding the baseband signal.

[0208] The wireless communication unit 910 can upconvert a baseband signal to an RF (radio frequency) band signal and transmit it via the antenna, and downconvert the RF band signal received via the antenna back to a baseband signal. For this purpose, the wireless communication unit 910 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC (digital to analog converter), and an ADC (analog to digital converter), etc.

[0209] The wireless communication unit 910 may include a large number of transmit / receive paths, and may include at least one antenna array consisting of a large number of antenna elements.

[0210] In terms of hardware, the wireless communication unit 910 may include a digital unit and an analog unit, and the analog unit may include a number of sub-units depending on the operating power, operating frequency, etc. The digital unit can be implemented by at least one processor (e.g., a DSP (digital signal processor)).

[0211] As described above, the wireless communication unit 910 can transmit and receive wireless signals. Therefore, all or part of the wireless communication unit 910 may be referred to as a "transmitter," "receiver," or "transceiver or transceiver." Furthermore, in the following description, transmission and reception via a wireless channel may include the processing described above being performed by the wireless communication unit 910.

[0212] The backhaul communication unit 920 can provide an interface for communicating with other nodes in the network. That is, the backhaul communication unit 920 can convert bit sequences transmitted from the base station to other nodes, such as other connected nodes, other base stations, higher-level nodes, and the core network, into physical signals, and can convert physical signals received from other nodes into bit sequences.

[0213] The storage unit 930 can store data such as basic programs, application programs, and configuration information for the operation of the base station. The storage unit 930 can be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. The storage unit 930 can then provide the stored data to the control unit 940 upon request.

[0214] The control unit 940 can control the overall operation of the base station. For example, the control unit 940 can transmit and receive signals via the wireless communication unit 910 or via the backhaul communication unit 920. The control unit 940 can also write and read data from the storage unit 930. Furthermore, the control unit 940 can perform the functions of the protocol stack required by the communication standard.

[0215] For this purpose, the control unit 940 may include at least one processor.

[0216] Through various embodiments of this disclosure, the control unit 940 can be controlled to perform the various operations performed by the base station described above.

[0217] The methods described in the claims of this disclosure or the embodiments described in the specification may be implemented in the form of hardware, software, or a combination of hardware and software.

[0218] When implemented in software, a computer-readable storage medium containing one or more programs (software modules) may be provided. The one or more programs stored on the computer-readable storage medium are configured for execution by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to perform the methods according to the embodiments described in the claims or specification of this disclosure.

[0219] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, ROM (read-only memory), electrically erasable programmable read-only memory (EEPROM), magnetic disc storage device, compact disc-ROM (CD-ROM), digital versatile discs (DVDs), or other forms of optical storage, or magnetic cassette. Alternatively, they may be stored in memory composed of some or all of these. Furthermore, each constituent memory may consist of multiple instances.

[0220] Furthermore, the program may be stored in an attachable storage device that can be accessed via a communication network such as the Internet, intranet, LAN (local area network), WAN (wide area network), or SAN (storage area network), or a combination thereof. Such a storage device may be connected to an apparatus performing an embodiment of the disclosure via an external port. Alternatively, a separate storage device on the communication network may be connected to an apparatus performing an embodiment of the disclosure.

[0221] In the specific embodiments of the Disclosure described above, the components included in the Disclosure are expressed singly or plurally by the specific embodiments presented. However, the singly or plural representations are selected to fit the context presented for the convenience of explanation, and the Disclosure is not limited to singly or plural components. Components expressed plural may consist singly, or components expressed singly may consist plural.

[0222] On the other hand, while specific embodiments have been described in the detailed description of this disclosure, it goes without saying that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the embodiments described, but should be defined not only by the claims described below, but also by something equivalent to these claims.

Claims

1. A method for operating a terminal (user equipment, UE) in a wireless communication system, The process of receiving configuration information from a base station (BS), Based on the aforementioned configuration information, the process involves designating a plurality of serving cells, including a first serving cell and a second serving cell, into a cell group. The process of performing PDCCH monitoring operations to receive downlink control information (DCI) for scheduling the cell group in the PDCCH (physical downlink control channel) search space set, The process of receiving the DCI from the base station based on the PDCCH monitoring operation, A process for identifying scheduling information for N serving cells belonging to the aforementioned cell group, The process includes receiving a data channel in at least one of the N serving cells based on the scheduling information, The PDCCH monitoring operation includes L PDCCH blind decoding operations, where the L PDCCH blind decoding operations are counted only for scheduling the first serving cell, where N and L are positive integers, and the L PDCCH blind decoding operations count the number of PDCCH blind decoding operations for scheduling the second serving cell to 0. A method by which the second serving cell is excluded from the number of scheduled cells (#).

2. The method according to claim 1, wherein at least one of the configuration information of the PDCCH search space set is set in the first serving cell, and the PDCCH search space set for the second serving cell only is not set in the terminal.

3. The method according to claim 1, wherein the total number of PDCCH blind decodings performed by the terminal for scheduling the first serving cell is determined by the number of scheduled cells, and the number of scheduled cells is counted according to the subcarrier interval of the scheduling cell.

4. The method according to claim 1, wherein the DCI is received from a third serving cell belonging to the base station, and the third serving cell is not the second serving cell.

5. The serving cell scheduled by the DCI is indicated by the first field of the DCI, The DCI's time domain resource allocation field includes information indicating an entry in the RRC (radio resource control) configuration table for each of the scheduled serving cells. The method according to claim 1, wherein the number of information blocks constituting the second field of the DCI is determined by the number of scheduled serving cells.

6. The method according to claim 5, wherein the first field is mapped to a fixed position within the DCI payload.

7. If at least one information block constituting a frequency domain resource allocation field is set to a specific code point, the process further includes identifying that at least one serving cell corresponding to the at least one information block is not scheduled by the DCI, The method according to claim 1, wherein the frequency domain resource allocation field is included in the DCI, and the at least one serving cell is included in the cell group.

8. Based on the field group corresponding to the serving cell with the lowest serving cell index among the at least one serving cell identified as not being scheduled, the terminal is instructed whether or not to activate the dormant bandwidth portion in the secondary cell configured on the terminal. The method according to claim 7, wherein the field group is included in the DCI.

9. The method according to claim 8, wherein the secondary cell is not included in the N serving cells.

10. The method according to claim 1, wherein a PDCCH monitoring omission section is instructed to the terminal based on the DCI, and the PDCCH search space set is not monitored by the terminal in the instructed omission section.

11. A method for operating a base station in a wireless communication system, The process of sending configuration information to the terminal (user equipment, UE), The process of transmitting downlink control information (DCI) to the aforementioned terminal, The process includes transmitting at least one data channel based on scheduling information for N serving cells included in the DCI, where N is a positive integer. The base station includes a plurality of serving cells, including a first serving cell and a second serving cell. The plurality of serving cells are identified as a cell group based on the configuration information, The method wherein the plurality of serving cells includes the N serving cells.

12. The method according to claim 11, wherein the DCI is transmitted from a third serving cell belonging to the base station, and the third serving cell is not the second serving cell.

13. The serving cell scheduled by the DCI is indicated by the first field of the DCI, The DCI's time domain resource allocation field includes information indicating an entry in the RRC (radio resource control) configuration table for each of the scheduled serving cells. The method according to claim 11, wherein the number of information blocks constituting the second field of the DCI is determined by the number of scheduled serving cells.

14. The method according to claim 13, wherein the first field is mapped to a fixed position within the DCI payload.

15. In a wireless communication system, in a terminal (user equipment, UE), The aforementioned terminal includes at least one transceiver, It includes a processor operably connected to at least one of the aforementioned transmitting and receiving units, The aforementioned at least one processor is Receive configuration information from the base station (BS), Based on the configuration information, a plurality of serving cells, including a first serving cell and a second serving cell, are designated as a cell group. In the PDCCH (physical downlink control channel) search space set, a PDCCH monitoring operation is performed to receive downlink control information (DCI) for scheduling the cell group. Based on the PDCCH monitoring operation, the DCI is received from the base station. Identify scheduling information for N serving cells belonging to the aforementioned cell group, Based on the scheduling information, the system is configured to receive data channels in at least one of the N serving cells. The PDCCH monitoring operation includes L PDCCH blind decoding operations, where the L PDCCH blind decoding operations are counted only for scheduling the first serving cell, and where N and L are positive integers. The L PDCCH blind decoding operations mentioned above count the number of PDCCH blind decoding operations for scheduling the second serving cell to 0. The aforementioned second serving cell is excluded from the number of scheduled cells (#) in the device.

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