KR20230062404A - Method of scheduling by multiple cells, and method of PDCCH offloading based thereon - Google Patents

Abstract

An operation method of a terminal in a carrier aggregation environment comprises the following steps of: blindly decoding PDCCH candidates performing scheduling for a first serving cell in the first serving cell; and blindly decoding PDCCH candidates performing scheduling for the first serving cell in a second serving cell. In this case, a search space group set in the first serving cell and a search space group set in the second serving cell can be interrelated. The terminal can monitor the interrelated search space groups in the second serving cell rather than the first serving cell.

Description

Scheduling method by multiple cells and PDCCH offloading method based thereon

The present invention relates to carrier aggregation in a mobile communication system, and more particularly, to a method in which a base station performs scheduling for a terminal using a plurality of cells and a PDCCH monitoring method of the terminal for this purpose.

Communication systems are continuously evolving to expand communication infrastructure for the realization of a hyper-connected society. For example, the NR communication system may support a frequency band up to around 100 GHz as well as a frequency band of 6 GHz or less, and compared to a conventional communication system (eg, a long-term evolution (LTE) communication system) More diverse services and scenarios can be supported. For example, a usage scenario of the NR communication system may include enhanced mobile broadband (eMBB), ultra reliable low latency communication (URLLC), and massive machine type communication (mMTC). In addition, the 6G communication system being discussed recently is expected to enable more diverse services and user experiences by utilizing THz frequency band, artificial intelligence, satellite communication, and quantum technology. There are various requirements in the industry that these communication systems must satisfy, and advanced communication technology is required to achieve them.

An object of the present invention to solve the above problems is to provide a scheduling method by multiple cells and a PDCCH offloading method based thereon.

Another object of the present invention to solve the above problems is to provide a configuration of devices for performing the method.

An embodiment of the present invention for achieving the above object is a method of operating a terminal in a carrier aggregation environment in which a first serving cell and a second serving cell are aggregated, scheduling for the first serving cell in the first serving cell blind decoding PDCCH candidates that perform; and blind decoding PDCCH candidates performing scheduling for the first serving cell in the second serving cell, wherein the first serving cell includes a first search space for PDCCH candidates for the first serving cell A set and a second search space set are set, a third search space set for PDCCH candidates for the first serving cell is set in the second serving cell, and the second search space set and the third search space set are When they are associated with each other and the first search space set is not correlated with the third search space set, the terminal monitors the first search space set and monitors the second search space set in the first serving cell. Otherwise, the third search space set may be monitored in the second serving cell.

Another embodiment of the present invention for achieving the above object is a method of operating a terminal in a carrier aggregation environment in which a first serving cell and a second serving cell are aggregated, scheduling for the first serving cell in the first serving cell Blind decoding the first PDCCH candidates that perform; and blind decoding second PDCCH candidates for scheduling the first serving cell and third PDCCH candidates for scheduling the second serving cell in the second serving cell, wherein the first The upper limit of the number of PDCCH candidates and the upper limit of the number of second PDCCH candidates are correlated with each other and are determined by the first subcarrier interval of the activated bandwidth portion of the first serving cell, and the upper limit of the number of third PDCCH candidates is It is determined by the second subcarrier interval of the bandwidth part activated in the second serving cell, and the number of serving cells corresponding to the first subcarrier interval is determined by the terminal regardless of the blind decoding operation for the second PDCCH candidates. can be determined

According to an embodiment of the present invention, a scheduling method by multiple cells and a PDCCH offloading method based thereon may be provided. Accordingly, the performance of the communication system can be improved.

1 is a conceptual diagram illustrating a first embodiment of a communication system.
Figure 2 is a block diagram showing a first embodiment of a device.
3 is a conceptual diagram illustrating a first embodiment of a carrier aggregation and arrangement method.
4 is a conceptual diagram illustrating a first embodiment of a multi-TRP based PDSCH transmission method.
5 is a conceptual diagram illustrating a first embodiment of a search space set mapping method considering multiple TRP transmissions.
6 is a conceptual diagram illustrating a second embodiment of a search space set mapping method considering multiple TRP transmissions.
7 is a conceptual diagram illustrating a third embodiment of a search space set mapping method considering multiple TRP transmissions.
8 is a conceptual diagram illustrating a fourth embodiment of a search space set mapping method considering multiple TRP transmissions.

Since the present invention can make various changes and have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention. The term "and/or" includes any combination of a plurality of related listed items or any of a plurality of related listed items.

In embodiments of the present application, “at least one of A and B” may mean “at least one of A or B” or “at least one of combinations of one or more of A and B”. Also, in the embodiments of the present application, “one or more of A and B” may mean “one or more of A or B” or “one or more of combinations of one or more of A and B”.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in this application, they should not be interpreted in an ideal or excessively formal meaning. don't

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in more detail. In order to facilitate overall understanding in the description of the present invention, the same reference numerals are used for the same components in the drawings, and redundant descriptions of the same components are omitted.

A communication system to which embodiments according to the present invention are applied will be described. The communication system may be a 4G communication system (eg, a long-term evolution (LTE) communication system, an LTE-A communication system), a 5G communication system (eg, a new radio (NR) communication system), a 6G communication system, and the like. there is. The 4G communication system can support communication in a frequency band of 6 GHz or less, and the 5G communication system can support communication in a frequency band of 6 GHz or more as well as a frequency band of 6 GHz or less. A communication system to which embodiments according to the present invention are applied is not limited to the contents described below, and embodiments according to the present invention can be applied to various communication systems. Here, the communication system may be used in the same sense as a communication network, "LTE" may indicate "4G communication system", "LTE communication system" or "LTE-A communication system", and "NR" may indicate "5G communication system" or "NR communication system".

In an embodiment, “setting an operation (eg, transmission operation)” means “setting information for the corresponding operation (eg, information element, parameter)” and/or “performing the corresponding operation”. It may mean that the "instructing information" is signaled. "Setting an information element (eg, parameter)" may mean that a corresponding information element is signaled. "Configuring a resource (eg, a resource region)" may mean that configuration information of a corresponding resource is signaled. Signaling is system information (SI) signaling (eg, transmission of system information block (SIB) and / or master information block (MIB)), RRC signaling (eg, transmission of RRC parameters and / or higher layer parameters) , MAC control element (CE) signaling, or PHY signaling (eg, transmission of downlink control information (DCI), uplink control information (UCI), and/or sidelink control information (SCI)).

1 is a conceptual diagram illustrating a first embodiment of a communication system.

Referring to FIG. 1, a communication system 100 includes a plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6). In addition, the communication system 100 includes a core network (eg, a serving-gateway (S-GW), a packet data network (PDN)-gateway (P-GW), and a mobility management entity (MME)). can include more. When the communication system 100 is a 5G communication system (eg, a new radio (NR) system), the core network includes an access and mobility management function (AMF), a user plane function (UPF), a session management function (SMF), and the like. can include

The plurality of communication nodes 110 to 130 may support communication protocols (eg, LTE communication protocol, LTE-A communication protocol, NR communication protocol, etc.) defined in the 3rd generation partnership project (3GPP) standard. The plurality of communication nodes 110 to 130 are CDMA (code division multiple access) technology, WCDMA (wideband CDMA) technology, TDMA (time division multiple access) technology, FDMA (frequency division multiple access) technology, OFDM (orthogonal frequency division) multiplexing) technology, filtered OFDM technology, CP (cyclic prefix)-OFDM technology, DFT-s-OFDM (discrete Fourier transform-spread-OFDM) technology, OFDMA (orthogonal frequency division multiple access) technology, SC (single carrier)-FDMA technology, NOMA (Non-orthogonal Multiple Access) technology, GFDM (generalized frequency division multiplexing) technology, FBMC (filter bank multi-carrier) technology, UFMC (universal filtered multi-carrier) technology, SDMA (Space Division Multiple Access) technology, etc. can support Each of the plurality of communication nodes may mean an apparatus or a device. Embodiments may be performed by an apparatus or device. The structure of the device (eg, device) may be as follows.

Figure 2 is a block diagram showing a first embodiment of a device.

Referring to FIG. 2 , an apparatus 200 may include at least one processor 210, a memory 220, and a transceiver 230 connected to a network to perform communication. In addition, the device 200 may further include an input interface device 240 , an output interface device 250 , a storage device 260 , and the like. Each component included in the device 200 may be connected by a bus 270 to communicate with each other.

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260 . The processor 210 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may include at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may include at least one of a read only memory (ROM) and a random access memory (RAM).

Referring back to FIG. 1, the communication system 100 includes a plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2), a plurality of terminals 130- 1, 130-2, 130-3, 130-4, 130-5, 130-6). Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may form a macro cell. Each of the fourth base station 120-1 and the fifth base station 120-2 may form a small cell. The fourth base station 120-1, the third terminal 130-3, and the fourth terminal 130-4 may belong to the cell coverage of the first base station 110-1. The second terminal 130-2, the fourth terminal 130-4, and the fifth terminal 130-5 may belong to the cell coverage of the second base station 110-2. The fifth base station 120-2, the fourth terminal 130-4, the fifth terminal 130-5, and the sixth terminal 130-6 may belong to the cell coverage of the third base station 110-3. there is. The first terminal 130-1 may belong to the cell coverage of the fourth base station 120-1. The sixth terminal 130-6 may belong to the cell coverage of the fifth base station 120-2.

Here, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 is a NodeB (NB), an evolved NodeB (eNB), a gNB, an advanced base station (ABS), and a HR -BS (high reliability-base station), BTS (base transceiver station), radio base station, radio transceiver, access point, access node, radio access station (RAS) ), MMR-BS (mobile multihop relay-base station), RS (relay station), ARS (advanced relay station), HR-RS (high reliability-relay station), HNB (home NodeB), HeNB (home eNodeB), It may be referred to as a road side unit (RSU), a radio remote head (RRH), a transmission point (TP), a transmission and reception point (TRP), and the like.

Each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 includes user equipment (UE), terminal equipment (TE), advanced mobile station (AMS), HR-MS (high reliability-mobile station), terminal, access terminal, mobile terminal, station, subscriber station, mobile station, mobile It may be referred to as a portable subscriber station, a node, a device, an on board unit (OBU), and the like.

Meanwhile, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may operate in different frequency bands or may operate in the same frequency band. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to each other through an ideal backhaul link or a non-ideal backhaul link, and , information can be exchanged with each other through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to the core network through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits a signal received from the core network to a corresponding terminal 130-1, 130-2, 130-3, and 130 -4, 130-5, 130-6), and signals received from corresponding terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 are transmitted to the core network can be sent to

In addition, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits MIMO (eg, single user (SU)-MIMO, multi-user (MU)- MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) transmission, carrier aggregation (CA) transmission, transmission in an unlicensed band, direct communication between devices (device to device communication, D2D) (or , proximity services (ProSe)), Internet of Things (IoT) communication, dual connectivity (DC), etc. may be supported. Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 is a base station 110-1, 110-2, 110-3, 120-1 , 120-2) and operations supported by the base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be performed. For example, the second base station 110-2 can transmit a signal to the fourth terminal 130-4 based on the SU-MIMO scheme, and the fourth terminal 130-4 uses the SU-MIMO scheme. A signal may be received from the second base station 110-2. Alternatively, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 and the fifth terminal 130-5 based on the MU-MIMO scheme, and the fourth terminal 130-4 And each of the fifth terminal 130-5 may receive a signal from the second base station 110-2 by the MU-MIMO method.

Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may transmit a signal to the fourth terminal 130-4 based on the CoMP scheme, and The terminal 130-4 may receive signals from the first base station 110-1, the second base station 110-2, and the third base station 110-3 by CoMP. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 includes a terminal 130-1, 130-2, 130-3, and 130-4 belonging to its own cell coverage. , 130-5, 130-6) and a CA method. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 controls D2D between the fourth terminal 130-4 and the fifth terminal 130-5. and each of the fourth terminal 130-4 and the fifth terminal 130-5 may perform D2D under the control of the second base station 110-2 and the third base station 110-3, respectively. .

The present invention relates to carrier aggregation in a mobile communication system, and more particularly, to a method in which a base station performs scheduling for a terminal using a plurality of cells and a PDCCH monitoring method of the terminal for this purpose. The following embodiments can be applied to an NR communication system, and can also be applied to other communication systems (eg, LTE communication system, 5G (fifth generation) communication system, 6G (sixth generation) communication system, etc.) in addition to the NR communication system.

Numerology applied to physical signals and channels in a communication system (eg, NR communication system, 6G communication system) may be variable. The numerology can be varied to meet the various technical requirements of a communication system. In a communication system to which a cyclic prefix (CP) based OFDM waveform technology is applied, the numerology may include a subcarrier interval and a CP length (or CP type). Table 1 may be a first embodiment of a numerology configuration method for a CP-OFDM based communication system. Adjacent subcarrier intervals may have an exponential multiplication of 2 with each other, and the CP length may be scaled by the same ratio as the OFDM symbol length. At least some of the numerologies of Table 1 may be supported according to the frequency band in which the communication system operates. In addition, numerology(s) not listed in Table 1 may be further supported in the communication system. For a specific subcarrier interval (eg, 60 kHz), CP type(s) (eg, extended CP) not listed in Table 1 may be additionally supported.

Table 1 relates to a first embodiment of a numerology configuration method for a CP-OFDM based communication system.

subcarrier spacing 15 kHz 30 kHz 60 kHz 120 kHz 240 kHz 480 kHz OFDM
Symbol length [μs] 66.7 33.3 16.7 8.3 4.2 2.1 CP length [us] 4.76 2.38 1.19 0.60 0.30 0.15 Number of OFDM symbols in 1 ms 14 28 56 112 224 448

Below, the frame structure of the communication system will be explained. Elements constituting a frame structure in the time domain may include subframes, slots, mini-slots, symbols, and the like. A subframe may be used as a unit of transmission or measurement, and the length of a subframe may have a fixed value (eg, 1 ms) regardless of a subcarrier interval. A slot may contain contiguous symbols (eg, 14 OFDM symbols). The length of the slot may be variable, different from the length of the subframe. For example, the length of a slot may be inversely proportional to the subcarrier spacing.

A slot may be used as a unit of transmission, measurement, scheduling, resource configuration, timing (eg, scheduling timing, hybrid automatic repeat request (HARQ) timing, channel state information (CSI) measurement and reporting timing, etc.). The length of an actual time resource used for transmission, measurement, scheduling, resource configuration, etc. may not match the length of a slot. A minislot may contain consecutive symbol(s), and the length of a minislot may be shorter than the length of a slot. A minislot may be used as a unit of transmission, measurement, scheduling, resource configuration, timing, and the like. The mini-slot (eg, the length of the mini-slot, the boundary of the mini-slot, etc.) may be predefined in the technical specification. Alternatively, the mini-slot (eg, mini-slot length, mini-slot boundary, etc.) may be set (or instructed) in the terminal. When a specific condition is satisfied, the use of the mini-slot may be set (or instructed) in the terminal.

The base station may schedule a data channel (eg, physical downlink shared channel (PDSCH), physical uplink shared channel (PUSCH), physical sidelink shared channel (PSSCH)) using some or all of the symbols constituting the slot. . In particular, a data channel may be transmitted using a portion of a slot for URLLC transmission, unlicensed band transmission, transmission in a coexistence situation between an NR communication system and an LTE communication system, and multi-user scheduling based on analog beamforming. Also, the base station may schedule a data channel using a plurality of slots. Also, the base station may schedule a data channel using at least one minislot.

Elements constituting the frame structure in the frequency domain may include a resource block (RB), a subcarrier, and the like. One RB may include consecutive subcarriers (eg, 12 subcarriers). The number of subcarriers constituting one RB may be constant regardless of numerology. In this case, the bandwidth occupied by one RB may be proportional to the subcarrier spacing of the numerology. An RB may be used as a unit of transmission and resource allocation of data channels, control channels, and the like. Resource allocation of the data channel may be performed in units of RBs or RB groups (eg, resource block group (RBG)). One RBG may include one or more contiguous RBs. Resource allocation of the control channel may be performed in units of control channel elements (CCEs). In the frequency domain, one CCE may include one or more RBs.

In a communication system, a slot (eg, slot format) is one or more of a downlink (DL) section, a flexible section (or unknown section), and an uplink (UL) section It may consist of a combination of Each of the downlink period, flexible period, and uplink period may consist of one or more consecutive symbols. The flexible period may be located between a downlink period and an uplink period, between a first downlink period and a second downlink period, between a first uplink period and a second uplink period, and the like. When a flexible period is inserted between a downlink period and an uplink period, the flexible period may be used as a guard period.

A slot may contain one or more flexible intervals. Alternatively, a slot may not include a flexible section. The terminal may perform a predefined operation in the flexible period. Alternatively, the terminal may perform semi-static or periodically set operations by the base station in the flexible period. For example, the operations periodically configured by the base station include a physical downlink control channel (PDCCH) monitoring operation, a synchronization signal/physical broadcast channel (SS/PBCH) block reception and measurement operation, and a channel state information-reference signal (CSI-RS) Reception and measurement operation, downlink SPS (semi-persistent scheduling) PDSCH reception operation, SRS (sounding reference signal) transmission operation, PRACH (physical random access channel) transmission operation, and PUCCH (physical uplink control channel) transmission operation configured periodically , a PUSCH transmission operation according to a configured grant, and the like. A flexible symbol may be overridden with a downlink symbol or an uplink symbol. When a flexible symbol is overridden by a downlink or uplink symbol, the terminal can perform a new operation instead of an existing operation in the corresponding flexible symbol (eg, the overridden flexible symbol).

The slot format may be set semi-fixedly by higher layer signaling (eg, radio resource control (RRC) signaling). Information indicating the semi-static slot format may be included in system information, and the semi-static slot format may be set cell-specifically. In addition, the semi-static slot format may be additionally configured for each UE through UE-specific higher layer signaling (eg, RRC signaling). A flexible symbol of a cell-specific slot format may be overridden with a downlink symbol or an uplink symbol by UE-specific higher layer signaling. In addition, the slot format may be dynamically indicated by physical layer signaling (eg, a slot format indicator (SFI) included in downlink control information (DCI)). A slot format set semi-fixedly can be overridden by a dynamically indicated slot format. For example, a semi-fixed flexible symbol may be overridden by a downlink symbol or an uplink symbol by SFI.

The base station and the terminal may perform a downlink operation, an uplink operation, a sidelink operation, and the like in a bandwidth part. The bandwidth portion may be defined as a set of RBs (eg, physical resource blocks (PRBs)) having a specific numerology. RBs constituting one bandwidth portion may be continuous in the frequency domain. One numerology may be used for signal transmission (eg control channel or data channel transmission) in one bandwidth portion. In embodiments, "signal" may refer to any physical signal and channel when used in a broad sense. A terminal performing an initial access procedure may obtain configuration information of an initial bandwidth part from a base station through system information. A UE operating in an RRC connected state may obtain configuration information of a bandwidth part from a base station through UE-specific higher layer signaling.

The setting information of the bandwidth part may include numerology (eg, subcarrier spacing and/or CP length) applied to the bandwidth part. In addition, the setting information of the bandwidth part further includes information indicating the location of the starting RB (eg, starting PRB) of the bandwidth part and information indicating the number of RBs (eg, PRBs) constituting the bandwidth part. can do. At least one bandwidth part among the bandwidth part(s) set in the terminal may be activated. For example, one uplink bandwidth portion and one downlink bandwidth portion may each be activated within one carrier. In a time division duplex (TDD) based communication system, a pair of an uplink bandwidth portion and a downlink bandwidth portion may be activated. The base station can set a plurality of bandwidth parts to the terminal within one carrier, and can switch the active bandwidth part of the terminal.

In embodiments, RB may mean a common RB (CRB). Alternatively, RB may mean PRB or virtual RB (VRB). In a communication system, a CRB may refer to an RB constituting a set of consecutive RBs (eg, a common RB grid) based on a reference frequency (eg, point A). Carriers, bandwidth portions, etc. may be placed on a common RB grid. That is, the carrier, bandwidth portion, etc. may be composed of CRB(s). An RB or CRB constituting the bandwidth portion may be referred to as a PRB, and a CRB index within the bandwidth portion may be appropriately converted to a PRB index. In an embodiment, RB may mean an interlace RB (IRB).

The smallest resource unit constituting the PDCCH may be a resource element group (REG). A REG may consist of one PRB (eg, 12 subcarriers) in the frequency domain and one OFDM symbol in the time domain. Accordingly, one REG may include 12 resource elements (REs). A demodulation reference signal (DM-RS) for decoding (or demodulation) of the PDCCH may be mapped to 3 REs among 12 REs constituting the REG, and control information (eg, modulated DCI) may be It can be mapped to the remaining 9 REs.

One PDCCH candidate may consist of one CCE or aggregated CCEs. One CCE may consist of a plurality of REGs. The NR communication system may support CCE aggregation levels 1, 2, 4, 8, 16, etc., and one CCE may consist of 6 REGs.

A control resource set (CORESET) may be a resource region in which a terminal performs blind decoding (or blind demodulation) of a PDCCH. CORESET may consist of a plurality of REGs. CORESET may consist of one or more PRBs in the frequency domain and one or more symbols (eg, OFDM symbols) in the time domain. Symbols constituting one CORESET may be consecutive in the time domain. PRBs constituting one CORESET may be continuous or discontinuous in the frequency domain. One DCI (eg, one DCI format, one PDCCH) may be transmitted within one CORESET. A plurality of CORESETs may be configured from a cell point of view or a terminal point of view, and the plurality of CORESETs may overlap each other in time-frequency resources.

CORESET may be set in the terminal by PBCH (eg, system information transmitted through PBCH, master information block (MIB)). ID (identifier) of CORESET set by PBCH may be 0. That is, CORESET set by PBCH may be referred to as CORESET #0. A UE operating in an RRC idle state may perform a monitoring operation in CORESET #0 to receive an initial PDCCH in an initial access procedure. Not only a terminal operating in an RRC idle state, but also a terminal operating in an RRC connected state can perform a monitoring operation in CORESET #0. CORESET may be set in the terminal by other system information (eg, system information block type 1 (SIB1)) in addition to system information transmitted through the PBCH. For example, in order to receive a random access response (or Msg2) in a random access procedure, the terminal may receive SIB1 including configuration information of CORESET. In addition, CORESET may be configured in the UE by UE-specific higher layer signaling (eg, RRC signaling).

One or more CORESETs for each downlink bandwidth portion may be configured for the UE. The UE may monitor the PDCCH candidate(s) for the CORESET set in the corresponding bandwidth portion in the downlink active bandwidth portion. Alternatively, the UE may monitor PDCCH candidate(s) for a CORESET (eg, CORESET #0) set in a downlink bandwidth portion other than the corresponding bandwidth portion in the downlink active bandwidth portion. The initial downlink active bandwidth part may include CORESET #0 and may be combined with CORESET #0. CORESET having a quasi co-location (QCL) relationship with the SS/PBCH block in the primary cell (PCell), secondary cell (SCell), and/or primary secondary cell (PSCell) #0 may be set for the terminal. In the secondary cell, CORESET #0 may not be set for the UE.

In this specification, a set of signals including a synchronization signal may be transmitted to the terminal(s), which may be referred to as SSB. Signals constituting the SSB may be predefined in technical specifications. A synchronization signal included in the SSB may be a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and the like. The SSB may further include the aforementioned signals (eg, PBCH, DM-RS for PBCH decoding, CSI-RS, etc.) in addition to the synchronization signal, and may be repeatedly transmitted through a beam sweeping operation. In an NR communication system, SSB may mean SS/PBCH block, and SSB resource may mean SS/PBCH block resource.

A search space may be a set of PDCCH candidate(s) or a set of resource regions occupied by the PDCCH candidate(s). The UE may perform blind decoding on each of the PDCCH candidates within a predefined search space. The UE can determine whether the PDCCH has been transmitted to itself by performing a cyclic redundancy check (CRC) on the blind decoding result. When it is determined that the PDCCH is a PDCCH for the UE, the UE may receive the PDCCH. The terminal may periodically monitor the search space, and may monitor the search space at one or more time positions (eg, PDCCH monitoring location, CORESET) within one period.

The PDCCH candidate may consist of CCE(s) selected by a predefined hash function within a CORESET or search space occasion. The search space may be defined/configured for each CCE aggregation level. In this case, the sum of search spaces for all CCE aggregation levels may be referred to as a search space set. A "search space" may mean a "search space set", and a "search space set" may mean a "search space".

A search space set may be logically associated with or correspond to one CORESET. One CORESET may be logically combined with or correspond to one or more search space sets. A search space set for transmitting a common DCI or a group common DCI may be referred to as a common search space set (hereinafter referred to as "CSS set"). Common DCI or group common DCI may include at least one of resource allocation information of PDSCH for transmission of system information, paging, power control command, SFI, or preemption indicator. In the case of an NR communication system, the common DCI may correspond to DCI formats 0_0, 1_0, etc., system information-radio network temporary identifier (SI-RNTI), paging-RNTI (P-RNTI), random access-RNTI (RA-RNTI) ), TC-RNTI (temporary cell-RNTI), etc., the common DCI cyclic redundancy check (CRC) may be scrambled and transmitted. The group common DCI may correspond to DCI format 2_X (X = 0, 1, 2, ??), etc., and the CRC of the group common DIC may be scrambled and transmitted using slot format indicator-RNTI (SFI-RNTI). CSS sets may include Type 0, Type 0A, Type 1, Type 2, and Type 3 CSS sets.

A search space set for transmitting a UE-specific DCI may be referred to as a UE-specific search space set (hereinafter referred to as a "USS set"). The UE-specific DCI may include scheduling and resource allocation information such as PDSCH, PUSCH, and PSSCH. In the case of an NR communication system, the UE-specific DCI may correspond to DCI formats 0_1, 0_2, 1_1, 1_2, 3_0, 3_1, etc., C-RNTI, CS-RNTI (configured scheduling-RNTI), MCS-C-RNTI ( modulation and coding scheme (C-RNTI), etc., the CRC of the UE-specific DCI may be scrambled and transmitted. Considering scheduling freedom or fallback transmission, a UE-specific DCI may be transmitted even in a CSS set. In this case, the UE-specific DCI may be transmitted according to a DCI format corresponding to the common DCI. For example, the UE can monitor a PDCCH (eg, DCI format 0_0, 0_1) in which a CRC is scrambled with C-RNTI, CS-RNTI, MCS-C-RNTI, etc. in a CSS set.

The terminal may monitor the fallback DCI (or fallback DCI format) in the CSS set. The payload size of the fallback DCI format may be fixed. Even if RRC resetting for the corresponding serving cell and/or bandwidth part is performed, the size of the fallback DCI does not change and can be used for scheduling even during RRC resetting. In the case of an NR communication system, the fallback DCI may include DCI formats 0_0, 1_0, and the like. The UE may monitor non-fallback DCI (or non-fallback DCI format) in the USS set. The payload size of the non-fallback DCI format may be changed by RRC resetting for a corresponding serving cell and/or bandwidth portion. In the case of an NR communication system, the non-fallback DCI may include DCI formats 0_1, 1_1, 0_2, 1_2, 3_0, 3_1, and the like. In addition, the UE may monitor the fallback DCI (or fallback DCI format) in the USS set. The UE may be configured to monitor only one DCI format among fallback DCI and non-fallback DCI in each USS set. The fallback DCI may correspond to a common DCI format and may also correspond to a UE-specific DCI format transmitted according to the common DCI format. The non-fallback DCI may correspond to a UE-specific DCI format (eg, a UE-specific DCI format transmitted according to a DCI format other than a common DCI format).

A type 0 CSS set may be used for reception of DCI scheduling a PDSCH including SIB1 and may be configured through PBCH or cell-specific RRC signaling. The ID of a type 0 CSS set may be given or set to 0. A type 0 CSS set can be logically combined with CORESET #0.

The UE may assume that the PDCCH DM-RS has a QCL relationship with a certain signal (eg, SS/PBCH block, CSI-RS, PDSCH DM-RS, PDCCH DM-RS, etc.). In addition, since the PDCCH has the same antenna port as the PDCCH DM-RS, the PDCCH and the PDCCH DM-RS may have a QCL relationship with each other. Therefore, the UE can obtain information on the large-scale propagation characteristics of the radio channel experienced by the PDCCH and the PDCCH DM-RS through the QCL assumption, and use the information on the large-scale propagation characteristics for channel estimation and reception beam formation. etc. can be used. The QCL parameter is at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, or spatial Rx parameter. can include The spatial reception parameter may correspond to at least one characteristic of a reception beam, a reception channel spatial correlation, or a transmission/reception beam pair. For convenience, the spatial reception parameter may be referred to as "spatial QCL". PDCCH may be used in the meaning of including PDCCH DM-RS, and that the PDCCH has a QCL relationship with a certain signal may include the meaning that the DM-RS of the PDCCH has a QCL relationship with the certain signal. A signal or resource having a PDCCH and QCL relationship may be referred to as a QCL source, a QCL source signal, or a QCL source resource.

PDCCHs transmitted in the same CORESET (and corresponding search space set, PDCCH monitoring occasion, etc.) may have the same QCL relationship. That is, an aggregation unit in which the UE assumes the same QCL may be a CORESET, and QCL assumptions in each of the CORESETs may be independent. In an embodiment, QCL, QCL source, etc. of a certain CORESET may mean QCL, QCL source, etc. of a PDCCH received through a corresponding CORESET, respectively. Exceptionally, different QCL assumptions may be applied to search space sets corresponding to one CORESET. For example, a search space set for monitoring RA-RNTI (eg, a type 1 CSS set) and other search space sets may have different QCL relationships.

The QCL relationship or QCL assumption (eg, QCL source, QCL type, etc.) of CORESET may be determined by a predefined method. For example, in a terminal, a PDCCH DM-RS received through a certain CORESET or a certain search space set is selected in the course of performing an initial access or random access procedure, and a SS/PBCH block and/or CSI-RS and a predefined QCL type It can be assumed to have a QCL relationship for . Here, the QCL type may mean a set of one or more QCL parameter(s). Alternatively, the QCL relationship or QCL assumption (eg, QCL source, QCL type, etc.) of the CORESET is signaled from the base station to the terminal (eg, RRC signaling, medium access control (MAC) control element (CE) signaling, DCI signaling) , a combination of the above signaling, etc.). That is, the base station may set a transmission configuration information (TCI) state for CORESET in the terminal. In general, a TCI state is an ID of a signal having a QCL relationship with a DM-RS (eg, PDCCH DM-RS) of a physical channel to which TCI is applied (eg, a QCL source and a QCL source resource of PDCCH DM-RS) And / or may include at least one QCL type therefor. For example, the base station may configure one or more TCI state candidates for each CORESET through RRC signaling to the UE, and MAC signaling (or DCI Signaling) can be instructed or set to the terminal. If there is one TCI state candidate configured by RRC signaling, the MAC signaling procedure (or DCI signaling procedure) may be omitted. The terminal may perform PDCCH monitoring and reception operations for the corresponding CORESET based on the TCI state configuration information received from the base station.

Beam operation of a high frequency band and a low frequency band in a communication system may be different from each other. In a low-frequency band (eg, a band of 6 GHz or less), since path loss of a signal due to a channel is relatively small, a signal may be transmitted and received using a beam having a wide beamwidth. In particular, in the case of a control channel, the entire coverage of a cell (or sector) can be covered even with a single beam. However, in a high-frequency band (eg, a band of 6 GHz or higher) in which a signal path loss is large, beamforming using a large-scale antenna may be used to increase a signal reach. In addition, beamforming may be applied not only to data channels but also to common signal and control channels. A communication node (eg, a base station) may form a beam having a small beam width through multiple antennas, and use a plurality of beams having different directivity to cover the entire spatial area of a cell (or sector). Thus, the signal can be transmitted and received multiple times. An operation of repeatedly transmitting a signal on a plurality of time resources using a plurality of beams may be referred to as a beam sweeping operation. A system that transmits a signal using a plurality of beams having a narrow beam width may be referred to as a multi-beam system.

For multi-beam system operation, the base station can manage transmission/reception beams of the terminal. In addition, the UE can manage its transmission/reception beams. The terminal may measure beam quality of a signal (eg, SSB, CSI-RS, etc.) transmitted from a base station or a transmission and reception point (TRP), and may report a beam quality measurement result to the base station. For example, the UE calculates beam quality measurement values such as reference signal received power (RSRP) and signal-to-interference-plus-noise ratio (SINR) for each beam (eg, each signal and each resource). and report the optimal beam(s) and the measurement value(s) corresponding thereto to the base station. The base station may determine a transmission beam for the terminal based on beam quality measurement information received from the terminal. In addition, the base station provides information (e.g., PDCCH, PDSCH, CSI-RS, PUCCH, PUSCH, SRS, PRACH, etc.) For example, QCL information, TCI state information, etc.) may be set in the terminal. In embodiments, unless otherwise specified, “beam” may mean “transmit beam”, “receive beam”, and/or “transmit/receive beam pair”. In addition, "beam", "transmission beam", "reception beam", "transmission/reception beam pair", etc. may have common meanings. Hereinafter, "transmission beam" may correspond to "precoder", "beamformer", "transmission spatial filter", etc., and information about transmission beams may correspond to information about a precoder, beamformer, transmission spatial filter, etc. , transmission spatial relationship information, spatial transmission parameters, and the like. In addition, the "receive beam" may correspond to a "receive filter", a "receive spatial filter", a "receive beamformer", and the like, and the information about the receive beam includes information about the receive filter, the receive spatial filter, the receive beamformer, and the like. It may mean information about QCL, information about QCL type D, reception spatial relationship information, spatial reception parameters, and the like. Also, hereinafter, “multiple beams” may mean at least one beam(s).

In embodiments, a base station or serving cell may include one or more TRPs, and downlink and/or uplink coverage may be formed by each TRP. The terminal may perform an operation of receiving a downlink signal from each TRP and an operation of transmitting an uplink signal to each TRP. Beamforming may be applied to downlink and uplink transmission. The transmit beam (or transmit spatial filter) of the terminal may be generated based on the receive beam (or receive spatial filter, beam quality measurement of the received signal) of the terminal. In addition, the transmission beam (or transmission spatial filter) of the base station or TRP may be generated based on the reception beam (or reception spatial filter, beam quality measurement of the received signal) of the base station or TRP. That is, beam correspondence may be established between a transmission beam and a reception beam of a communication node. Hereinafter, for convenience, when a communication node transmits or receives a beam, it may mean transmitting or receiving a signal to which a corresponding beam is applied.

Meanwhile, a carrier aggregation method may be applied to the terminal. That is, the terminal may be configured with a plurality of carriers (ie, component carriers), and transmit/receive with the base station by aggregating the plurality of carriers. Here, a carrier may have the same meaning as a cell or a serving cell. In the case of an NR communication system, up to 16 carriers can be aggregated in one terminal. Assuming that the maximum bandwidth of one carrier is 400 MHz, one terminal can utilize a bandwidth of up to 6.4 GHz (= 16*400 MHz) for transmission, and thus the peak data rate of the terminal can increase. A plurality of aggregated carriers may or may not be adjacent to each other in the frequency domain. Also, a plurality of carriers may belong to the same frequency band or to different frequency bands. One or more downlink bandwidth parts and one or more uplink bandwidth parts may be set for each carrier, and a sidelink bandwidth part may be additionally set for a certain carrier. The terminal may perform operations such as transmission and measurement on the active bandwidth portion of the activated carrier(s).

A UE to which carrier aggregation is applied may have one primary cell (PCell) and one or more secondary cell (s) SCell(s). The terminal may determine the PCell in the process of performing procedures such as initial cell search, cell reselection, and handover. On the other hand, the SCell may be configured in a terminal (eg, a terminal in an RRC connected state) through a signaling procedure (eg, RRC signaling) from the base station. The SCell may be activated and deactivated, and activation and deactivation may also be controlled through a signaling procedure from the base station (eg, DCI, medium access control (MAC) control element (CE), RRC signaling, etc.). Configuration of PCell and SCell may be UE-specific. That is, the same serving cell may operate as a PCell for some UEs and as a SCell for other UEs. Alternatively, a plurality of terminals may use different serving cells as PCells. In the case of a frequency division duplex (FDD) cell, a serving cell may consist of only downlink carriers or only uplink carriers. Also, a serving cell may include a plurality of uplink carriers or may include a plurality of downlink carriers. When the serving cell includes a plurality of uplink (or downlink) carriers, the serving cell may include a supplementary uplink (or downlink) carrier.

In the carrier aggregation scheme, a DCI (or PDCCH) scheduling a data channel may be transmitted on the same carrier as the carrier on which the data channel is transmitted. This method may be referred to as self-scheduling. Alternatively, the DCI (or PDCCH) scheduling the data channel may be transmitted on a carrier different from the carrier through which the data channel is transmitted. This scheme may be referred to as cross-carrier scheduling. Cross-carrier scheduling may be used for purposes such as offloading control channels and controlling interference between control channels. In this case, the scheduled data channel may be a data channel including unicast data or UE-specific data (eg, downlink-shared channel (DL-SCH) or uplink-shared channel (UL-SCH)). In addition, the DCI for scheduling the data channel may mean a DCI or a DCI format in which a CRC is scrambled such as C-RNTI, CS-RNTI, MCS-C-RNTI, or the like. One of the self-scheduling method and the cross-carrier scheduling method may be applied to each carrier or serving cell.

A carrier through which scheduling DCI is transmitted may be referred to as a scheduling cell, and a carrier through which a data channel (eg, PDSCH or PUSCH) is transmitted may be referred to as a scheduled cell. In the case of self-scheduling, the scheduling cell and the scheduled cell may coincide. In the case of cross-carrier scheduling, a scheduling cell and a scheduled cell may be different from each other. The UE may perform a PDCCH monitoring operation corresponding to the scheduled cell in the scheduling cell. An association relationship between a scheduling cell and a scheduled cell may be configured in a UE through a higher layer signaling (eg, RRC signaling) procedure.

HARQ-acknowledgement (HARQ-ACK) information, which is a reception response of the PDSCH, may be transmitted through the PUCCH. In this case, the UE may transmit the PUCCH including the HARQ-ACK information to the BS through the PCell. In addition, for the purpose of reducing the PUCCH overhead concentrated on the PCell, the terminal may be additionally configured with a cell capable of transmitting a PUCCH including HARQ-ACK (hereinafter referred to as a “PUCCH cell”) in addition to the PCell. For example, one PCell and one SCell may be configured as PUCCH cells for a UE. In addition, a PUCCH cell group mutually coupled to each PUCCH cell may be configured for the UE. HARQ-ACK information for a PDSCH transmitted through a serving cell belonging to a PUCCH cell group may be transmitted through a corresponding PUCCH cell.

Meanwhile, a communication service provider may want to simultaneously provide services of heterogeneous communication systems (eg, an NR communication system and an LTE communication system) using the same frequency band. To this end, the carrier of the NR communication system (hereinafter referred to as "NR carrier") and the carrier of the LTE communication system (hereinafter referred to as "LTE carrier") may be overlapped in a certain frequency domain, and the NR carrier and the LTE carrier may be Spectrum can be dynamically shared according to traffic conditions (a dynamic spectrum sharing (DSS) scenario). That is, the NR signal of the NR carrier and the LTE signal of the LTE carrier may be dynamically multiplexed and transmitted to resources such as time, frequency, and space within the same frequency domain. For example, a base station (or a base station of an NR communication system) may transmit fewer signals on an NR carrier overlapping with an LTE carrier when the traffic of the LTE communication system is high, and overlapping with the LTE carrier when the traffic of the LTE communication system is low. A signal can be transmitted using many physical resources in an NR carrier.

3 is a conceptual diagram illustrating a first embodiment of a carrier aggregation and arrangement method.

Referring to FIG. 3 , in a communication system (eg, NR communication system), one PCell and at least one SCell may be carrier aggregated in a terminal. For example, a PCell may be an FDD cell and a SCell may be a TDD cell. In this case, the downlink carrier of the PCell may overlap with a carrier (eg, LTE carrier) of another communication system. In this case, a portion of downlink physical resources of the PCell may be used for LTE signal transmission or pre-occupied for LTE signal transmission. Accordingly, the size of a resource region that can be used for NR signal transmission in the downlink carrier of PCell may be limited. In particular, CORESET may be set in a limited resource region of PCell, which may cause a decrease in PDCCH transmission capacity of PCell. If the PDCCH transmission capacity is small, a case may occur in which a data channel (eg, PUSCH) cannot be scheduled even though available resources (eg, PCell uplink resources) are sufficient for transmission of the data channel. Accordingly, spectrum efficiency may decrease and transmission delay time may increase.

As a method for solving the above problem, a cross-carrier scheduling scheme may be applied to the PCell or the PSCell (hereinafter collectively referred to as the PCell). For example, the SCell may be configured and/or activated in the UE, and cross-carrier scheduling from the SCell to the PCell may be used. The base station may transmit a DCI (or PDCCH) scheduling a data channel (eg, PDSCH, PUSCH) of the PCell to the terminal through a cell (eg, SCell) other than the PCell. When it is determined that the DCI received from the SCell is DCI for the PCell (eg, data channel scheduling of the PCell), the UE may perform a PDSCH reception operation or a PUSCH transmission operation in the PCell based on scheduling information of the DCI. . For example, DCI received in a specific CORESET of SCell, a specific search space set, a specific monitoring occasion, etc. may be regarded as a DCI for PCell, and this operation may be set (or instructed) in the UE. When the DCI received from the SCell includes a carrier indicator field (CIF) corresponding to the PCell, the UE may regard the corresponding DCI as a DCI for the PCell. For example, the terminal can monitor the non-fallback DCI format for PCell scheduling in the USS set of SCell.

In addition, as a method for responding to a case where link performance of the SCell deteriorates or beam failure occurs, the terminal may perform a PDCCH monitoring operation in both the SCell and the PCell to receive scheduling information of the PCell. That is, a self-scheduling scheme (eg, a self-scheduling scheme from the PCell) and a cross-carrier scheduling scheme (eg, a cross-carrier scheduling scheme from the SCell) may be simultaneously applied to one serving cell (eg, PCell). The monitoring operation in the PCell and the monitoring operation in the SCell may both (or together) be performed within the same reference time. In addition, both fallback DCI and non-fallback DCI may be monitored for scheduling for one serving cell (eg, PCell). According to the above-described method, even if “the RRC reset procedure of the serving cell (eg, PCell) is performed” and/or “the link quality of the serving cell whose DCI is monitored is degraded”, the corresponding serving cell ( For example, scheduling for PCell) may be performed. According to some embodiments, the fallback DCI may be selectively transmitted in the CSS set and the USS set. In addition, the terminal may monitor non-fallback DCI in a plurality of serving cells (eg, PCell and SCell) in order to receive scheduling information for a certain serving cell (eg, PCell). According to this, even when the link quality of a serving cell whose DCI is monitored deteriorates, scheduling by non-fallback DCI can be performed through another serving cell.

More generally, one serving cell (ie, the scheduled cell) may be scheduled from multiple serving cells (ie, scheduling cells). The scheduled cell and the scheduled cells may be any serving cell(s) configured in the UE. The method described above may be referred to as (method 100). In (method 100), the scheduled cell may be a serving cell different from the scheduling cells. In this case, cross-carrier scheduling from a plurality of serving cells may be applied to the scheduled cell. Alternatively, the scheduled cell may coincide with one of the scheduling cells. In this case, both self-scheduling and cross-carrier scheduling may be applied to the scheduled cell. This may be referred to as (Method 110).

A cell to be scheduled may be a PCell, PSCell, or SCell. Cells for scheduling may include PCell, PSCell, and/or SCell. PSCell may be effective when dual connectivity technology is applied to the terminal. Embodiments may be used for cross-carrier scheduling within a primary cell group or a secondary cell group. When the embodiments are used for cross-carrier scheduling within a secondary cell group, the PCell may correspond to the PSCell. In the embodiments, two scheduling cells will be mainly considered, but the embodiments can be easily extended to three or more scheduling cells. When there are two scheduling cells, the scheduling cells may be referred to as a first scheduling cell and a second scheduling cell, respectively. (Method 100) may include the above-described DSS scenario as an embodiment. In a DSS scenario, a scheduled cell may be a PCell (or PSCell) and the cells to be scheduled may be the PCell (or the PSCell) and the SCell. The cell being scheduled may coincide with one of the scheduling cells.

The maximum number of PDCCH blind decoding (BD) that can be performed per reference time for each serving cell (eg, scheduled cell) configured or activated in the UE (hereinafter referred to as “N _BD ”) and processing (eg, Channel Estimation) The maximum number of possible CCEs (hereinafter referred to as "N _CCE ") may be defined. The reference time may be each slot, each PDCCH monitoring span, or P consecutive slots. P may be a natural number. One or more PDCCH monitoring spans may be arranged within one slot. There may be slots in which the PDCCH monitoring span is not allocated. When cross-carrier scheduling is used, a slot or PDCCH monitoring span may refer to a slot or PDCCH monitoring span of a scheduling cell (or a bandwidth portion of a scheduling cell (eg, an active bandwidth portion, a configured bandwidth portion)). there is. Each of N _BD and N _CCE may be determined by a numerology (eg, subcarrier interval) of a bandwidth part (eg, an active bandwidth part, a configured bandwidth part) of a scheduling cell (or a scheduling cell).

According to (method 100), a UE may perform PDCCH monitoring in a plurality of scheduling cells for PDSCH/PUSCH scheduling for one scheduled cell. In this case, numerologies (eg, subcarrier intervals and/or CP types) of a plurality of cells to be scheduled may be different from each other. For example, the terminal may monitor the search spaces of the first scheduling cell and the second scheduling cell for scheduling of one scheduled cell. In this case, the numerologies (or subcarrier spacing) of the first scheduling cell and the second scheduling cell are the first numerology (or first subcarrier spacing) and the second numerology (or second subcarrier spacing), respectively. ) can be referred to as In this case, the BD and CCE counting of scheduling cells for scheduling of the scheduled cell may be performed based on one scheduling cell (or its active bandwidth portion). The one scheduling cell (or active bandwidth portion thereof) may be referred to as a reference serving cell, and a numerology corresponding thereto may be referred to as a reference numerology.

The reference numerology may be determined as one of the first numerology and the second numerology according to a predefined rule or a signaling procedure from the base station. For example, the reference numerology may be a numerology having a smaller (or larger) subcarrier interval between the first numerology and the second numerology. In general, the reference numerology may be a numerology having the smallest (or largest) subcarrier interval among numerologies corresponding to all bandwidth parts configured in cells to be scheduled. Alternatively, the reference numerology may be a numerology having the smallest (or largest) subcarrier spacing among numerologies corresponding to all bandwidth parts set in one of the cells for scheduling. A reference numerology may be referred to as a reference subcarrier interval. According to the above method, an integer number of slot(s) may be included in each reference time for each cell to be scheduled.

The UE may perform PDCCH monitoring and channel estimation for this operation based on the capabilities of N _BD and N _CCE at each reference time. In the case of a serving cell in which PDCCH overbooking is allowed, the _UE sets search space sets ( _e.g. , search PDCCH candidates belonging to the spatial set) may be sequentially mapped. The UE can perform a blind decoding operation only on PDCCH candidates belonging to the mapped search space set, and can omit the blind decoding operation on PDCCH candidates belonging to the unmapped search space set. At this time, the terminal may first map the CSS set(s) and then map the USS set(s). The terminal may not expect that the CSS set is not mapped. For example, all PDCCH candidates belonging to the CSS set can be constantly monitored by the UE. Also, search space sets (eg, USS sets) may be sequentially mapped based on IDs of the search space sets (eg, in descending order of search space set IDs).

In (method 100), N _BD and N _CCE may be applied to each of a plurality of scheduling cells, and the above-described PDCCH monitoring operation may be performed in each of a plurality of scheduling cells. Hereinafter, specific embodiments for this are described. Embodiments will be described mainly for N _BD , but the same method can be applied for N _CCE as well. In embodiments, the first subcarrier spacing corresponding to the first scheduling cell may be denoted as μ1, and the second subcarrier spacing corresponding to the second scheduling cell may be denoted as μ2. In addition, the subcarrier interval corresponding to the scheduled cell may be referred to as a third subcarrier interval and may be expressed as μ3. When (method 110) is used, the scheduled cell may coincide with the first scheduling cell, and μ3=μ1. The first scheduling cell may be self-scheduled by the first scheduling cell or cross-carrier scheduled by the second scheduling cell.

In this specification, M ^max,slot,μ may mean the maximum number of BDs (or maximum number of CCEs) allowed for each slot of a serving cell with a subcarrier interval μ. M ^max,slot,μ can be predefined in technical specifications. In addition, M ^{total, slot, μ} is the maximum number of BDs (or maximum number of CCEs) that the UE can perform in each slot for all serving cells with a subcarrier interval μ when carrier aggregation is configured. can mean sum. For example, M ^{total,slot,μ} is M ^{total,slot,μ} =floor(N ^cap * M ^max,slot,μ * (N _cells ^DL,μ / sum _j=0,1,??,J (N _cells ^DL,j )), where N ^cap is a value related to the PDCCH monitoring capability reported by the UE to the base station, and may mean the number of downlink cell(s). N _cells ^DL,μ is It may mean the number of cell(s) with a subcarrier interval μ among downlink cells configured in the UE. floor(.) may mean a rounding operation, and sum _μ (f(μ)) is a given μ value ( s) For example, μ = 0, 1, 2, and 3 correspond to subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, and 120 kHz, respectively It can be.

First, an embodiment for (Method 110) is described.

According to the first embodiment, the terminal performs up to N _BD,1 = f(A, M ^max,slot,μ1 for each reference time of the first scheduling cell (eg, each slot of the first scheduling cell) in the first scheduling cell. , M ^{total, slot, μ 1} ) PDCCH candidates can be monitored. For example, it may be N _BD,1 =A*min(M ^max,slot,μ1 , M ^{total,slot,μ1} ). In addition, for each reference time of the first scheduling cell in the second scheduling cell (eg, each slot of the first scheduling cell), the UE maximum N _BD,2,μ1 = f(B, M ^max,slot,μ1 , M ^{total , slot, μ 1} ) PDCCH candidates can be monitored. For example, it may be N _BD,2,μ1 =B*min(M ^max,slot,μ1 , M ^{total,slot,μ1} ). A and B can be numbers greater than or equal to 0. A and B can be determined or set independently. Alternatively, A and B may be interrelated. For example, it may be B=1-A. In this case, A and B may be 0 or more and 1 or less. According to this, the terminal has a maximum of N _BD,1 +N _BD,2,μ1 = f(A+B, M ^max,slot,μ1 , M ^total,slot in the first scheduling cell and the second scheduling cell for the subcarrier interval μ1 ^,μ1 )=min(M ^max,slot,μ1 , M ^{total,slot,μ1} ) number of PDCCH candidates can be monitored, and this value is for the first scheduling cell when cross-carrier scheduling by the second scheduling cell is excluded. It can match the maximum number of BDs. That is, according to (method 110), a part of the BD capability in the first scheduling cell can be offloaded to the second scheduling cell. A and / or B may be configured through a signaling procedure (eg, RRC signaling procedure) from the base station to the terminal.

At the same time, the terminal in the second scheduling cell for each reference time of the second scheduling cell (eg, each slot of the second scheduling cell) up to N _BD,2,μ2 = f(M ^{total,slot,μ2} ) or up to N _BD,2,μ2 = f(M ^max,slot,μ2 , M ^{total,slot,μ2} ) number of PDCCH candidates can be monitored. For example, N _BD,2,μ2 =M ^{total,slot,μ2} or N _BD,2,μ2 =min(M ^max,slot,μ2 , M ^{total,slot,μ2} ). That is, in the PDCCH monitoring operation in the serving cell performing cross-carrier scheduling, a condition determined based on μ1 (eg, N _BD,2,μ1 ) and a condition determined based on μ2 (eg, N _BD,2,μ2) ) can be applied simultaneously.

In the above embodiment, when counting the number of downlink cell(s) for each subcarrier interval, the first scheduling cell may be counted once and the second scheduling cell may not be counted. Alternatively, the first scheduling cell may be counted X times and the second scheduling cell may be counted Y times. Here, X and Y may be integers greater than or equal to 0. Alternatively, X and Y may be real numbers greater than or equal to zero. X and Y may be independently determined or set. Alternatively, X and Y may be correlated. X and / or Y may be configured through a signaling procedure (eg, RRC signaling procedure) from the base station to the terminal.

In the above embodiment, excessive PDCCH configuration may be allowed for some serving cells among the first scheduling cell and the second scheduling cell. For example, the first scheduling cell may be a PCell (or PSCell). In this case, excessive PDCCH configuration may be allowed in the first scheduling cell. When the number of PDCCH candidates or CCEs greater than the upper limit of the number of BDs and the number of CCEs determined by the method is set in the first scheduling cell, the UE may sequentially map the PDCCH candidates by the above-described procedure, and the mapped PDCCH candidates can be monitored.

Next, an embodiment for (Method 100) is described.

In (method 100), the scheduled cell may generally be different from the first scheduling cell and the second scheduling cell, and μ3 may be generally equal to or different from μ1 and μ2. According to the second embodiment for (method 100), the upper limit of the number of BD/CCEs in the first scheduling cell and the second scheduling cell may be determined based on μ1 and μ2. That is, the upper limit of the number of BD/CCEs may be determined based on the subcarrier spacing of the cell(s) to be scheduled, and may be determined regardless of the subcarrier spacing of the scheduled cell. For example, the method applied to the first embodiment may be equally applied to the PDCCH monitoring operation. That is, the UE can monitor up to the N _BD,1 PDCCH candidates in each slot of the first scheduling cell. In addition, the terminal may monitor up to N _BD,2,μ1 PDDCH candidates for each slot duration of the first scheduling cell in the second scheduling cell, and up to N _BD,2,μ2 in each slot of the second scheduling cell. PDCCH candidates can be monitored. According to the above method, the number of BD/CCEs of some scheduling cells (eg, first scheduling cells) can be determined only by their own subcarrier spacing (eg, μ1), and some other scheduling cells (eg, second scheduling cells) ) may be determined by both its own subcarrier spacing (eg, μ2) and the subcarrier spacing (eg, μ1) of another scheduling cell (eg, the first scheduling cell). That is, any one subcarrier interval (eg, μ1) among μ1 and μ2 may be involved in determining the number of BD/CCEs of a plurality of scheduling cells. Any one of the subcarrier intervals may be referred to as a reference subcarrier interval, and a serving cell and a numerology corresponding thereto may be referred to as a reference serving cell and a reference numerology, respectively.

A reference serving cell or reference subcarrier spacing may be determined based on sizes of subcarrier spacings of serving cells. For example, a serving cell having the smallest (or largest) subcarrier spacing may be determined as the reference serving cell, and the corresponding subcarrier spacing may be determined as the reference subcarrier spacing. Alternatively, the reference serving cell or reference subcarrier interval may be determined based on the size of cell IDs of serving cells, the size of the maximum number of BD/CCEs in serving cells, and the like.

According to the third embodiment for (method 100), the upper limit of the number of BD/CCEs in the first scheduling cell and the second scheduling cell may be determined based on μ1 and μ2 as well as μ3. That is, the upper limit of the number of BD/CCEs may be determined based on both the subcarrier spacing of the scheduling cell(s) and the subcarrier spacing of the scheduled cell. For example, the number of BD/CCEs of the first scheduling cell may be determined by its subcarrier spacing μ1 and the subcarrier spacing μ3 of the cell to be scheduled, and the number of BD/CCEs of the second scheduling cell may be determined by its subcarrier spacing μ2 and the scheduling cell's subcarrier spacing μ2. It can be determined by the subcarrier spacing μ3 of the cell to be At the same time, the number of BD/CCEs of the first scheduling cell may be determined regardless of the subcarrier spacing μ2 of the second scheduling cell. Also, the number of BD/CCEs of the second scheduling cell may be determined regardless of the subcarrier interval μ1 of the first scheduling cell.

For example, M ^{total,slot,μ3} or min(M ^max,slot,μ3 , M ^{total,slot,μ3} ) upper limit values based on μ3 may be distributed to the first scheduling cell and the second scheduling cell. For each unit time (eg, each slot of the first scheduling cell or each slot of the cell to be scheduled) in the first scheduling cell, the terminal has a maximum of A * M ^{total, slot, μ 3} or A * min (M ^{max, slot, μ 3} , M ^{total, slot, μ 3} ) PDCCH candidates can be monitored, and for each unit time in the second scheduling cell (eg, each slot of the second scheduling cell or each slot of the scheduled cell), up to B * M ^{total, Slot,μ3} or B*min (M ^max,slot,μ3 , M ^{total,slot,μ3} ) PDCCH candidates can be monitored. A and B can be determined by the method described above. At the same time, the UE may monitor up to M ^{total,slot,μ1} or min(M ^max,slot,μ1 , M ^{total,slot,μ1} ) PDCCH candidates for each unit time of the first scheduling cell, and Up to M ^{total,slot,μ2} or min(M ^max,slot,μ2 , M ^{total,slot,μ2} ) PDCCH candidates can be monitored for each unit time of the scheduling cell. Meanwhile, transmission of a data channel (eg, PDSCH, PUSCH) may be performed by multiple TRPs.

4 is a conceptual diagram illustrating a first embodiment of a multi-TRP based PDSCH transmission method.

Referring to FIG. 4 , a plurality of TRPs included in a base station, that is, a first TRP and a second TRP may respectively transmit a first PDSCH and a second PDSCH to a terminal. TRPs may be connected to each other with a backhaul (eg, non-ideal backhaul or ideal backhaul). The TB (transport block) (s) included in the first PDSCH and the TB (s) included in the second PDSCH may be independent or different from each other, and the HARQ process corresponding to the first PDSCH and the HARQ process corresponding to the second PDSCH Processes can be different.

The first PDSCH and the second PDSCH may be scheduled by the first DCI and the second DCI, respectively. The plurality of DCIs may be transmitted by different TRPs. For example, the first DCI may be transmitted by the first TRP and may be included in the first PDCCH and transmitted. The second DCI may be transmitted by the second TRP and may be included in the second PDCCH and transmitted. The payload of the first DCI and the payload of the second DCI may be the same, and the first DCI and the second DCI may follow the same DCI format. The first DCI and the second DCI may be DCIs that are repeatedly transmitted. Also, the first PDCCH and the second PDCCH may be repeatedly transmitted PDCCHs.

A set of CORESET(s) for monitoring PDCCHs transmitted by the same TRP may be configured in the UE. This may be referred to as a CORESET pool. For example, a first CORESET pool and a second CORESET pool may be configured in the UE to monitor PDCCHs transmitted by the first TRP and the second TRP, respectively. Different CORESET pool IDs may be allocated to the first CORESET pool and the second CORESET pool. For example, the ID of the first CORESET pool may be 0 and the ID of the second CORESET pool may be 1. CORESET(s) belonging to the same CORESET pool can have the same TCI status or the same QCL set. The UE is in the same TCI state or the same QCL in the CORESET(s) (and its corresponding search space set(s), PDCCH monitoring location(s), or PDCCH candidate(s)) belonging to the same CORESET pool based on the configuration. The assumption can be applied and the PDCCH can be monitored or received.

In the above embodiment, the first DCI and the second DCI may belong to different CORESET pools. For example, the first DCI and the second DCI may belong to the first CORESET pool and the second CORESET pool, respectively. That is, the first DCI may be monitored in a search space set correlated with CORESETs belonging to the first CORESET pool, and the second DCI may be monitored in a search space set correlated with CORESETs belonging to the second CORESET pool. The first DCI may be monitored based on the TCI state or QCL assumption of the first CORESET pool, and the second DCI may be monitored based on the TCI state or QCL assumption of the second CORESET pool.

The above-described multiple TRP transmission method may be referred to as a multiple DCI-based multiple TRP PDSCH transmission method. The above method may be set in units of serving cells. When carrier aggregation is configured in the terminal, the above-described method may be configured for some of the aggregated serving cells. In this case, the UE can perform more BDs or monitor more CCEs in the serving cell in which the plurality of CORESET pools are configured than in the serving cell in which the plurality of CORESET pools are not configured. For example, assuming that the subcarrier interval is μ, the UE has a maximum of N _BD,0 =min(M ^max,slot,μ for each reference time (eg, each slot) in a serving cell in which a plurality of CORESET pools are not configured , M ^{total, slot, μ} ) PDCCH candidates can be monitored. On the other hand, the UE has a maximum of N _BD,1 =min(K*M ^max,slot,μ , M ^{total,slot,μ} ) PDCCH candidates for each reference time (eg, each slot) in a serving cell in which a plurality of CORESET pools are set can be monitored. In addition, the UE may monitor up to N _BD,1,pool =min(M ^max,slot,μ , M ^{total,slot,μ} ) PDCCH candidates for CORESETs belonging to each CORESET pool in the serving cell. At this time, if K>1, N _BD,m may be greater than N _BD,s . In addition, the value of M ^{total, slot, μ} may be calculated by different methods when a serving cell including a plurality of CORESET pools is set in the terminal and when it is not. When a serving cell including a plurality of CORESET pools is not set in the UE, M ^{total, slot, μ} may be calculated by the above-described method. On the other hand, when a serving cell including a plurality of CORESET pools is set in the terminal, M ^{total,slot,μ} is M ^{total,slot,μ} =floor(N ^cap * M ^max,slot,μ * ((N _cells,0 ^{DL ,μ} + K*N _cells,1 ^DL,μ ) / sum _j=0,1,??,J (N _cells,0 ^DL,j + K*N _cells,1 ^DL,j )) Here, N _cells,0 ^DL,μ may be the number of serving cell(s) in which multiple CORESET pools are not configured, and N _cells,1 ^DL,μ are multiple CORESET pools configured (ie, multiple DCI It may be the number of serving cells (s) to which the based multiple TRP PDSCH transmission method is applied. According to the above formula, when counting the number of serving cells configured in the UE for each subcarrier interval, the serving cell configured with the plurality of CORESET pools is It can be counted by K cells instead of 1. K does not have to be an integer and can be a real number greater than or equal to 0. For example, K can have values such as 1, 1.5, and 2.

When (method 100) is used, the multiple DCI-based multiple TRP PDSCH transmission method may be applied to some serving cells among a plurality of scheduling cells that schedule the same cell. A plurality of CORESET pools may be configured for a UE in the some serving cells, and the UE may monitor search space sets corresponding to the plurality of CORESET pools based on a corresponding TCI state or QCL assumption. Hereinafter, a PDCCH monitoring method of the UE for the above case will be described.

5 is a conceptual diagram showing a first embodiment of a search space set mapping method considering multiple TRP transmissions, and FIG. 6 is a conceptual diagram showing a second embodiment of a search space set mapping method considering multiple TRP transmissions. is a conceptual diagram illustrating a third embodiment of a search space set mapping method considering multiple TRP transmissions, and FIG. 8 is a conceptual diagram illustrating a fourth embodiment of a search space set mapping method considering multiple TRP transmissions.

Referring to FIGS. 5 to 8 , a first serving cell and a second serving cell may be configured in a terminal. A first subcarrier spacing (or μ1) and a second subcarrier spacing (or μ2) may be used in the first serving cell and the second serving cell, respectively. According to (method 100), the third serving cell configured in the terminal may be scheduled by the first serving cell and the second serving cell. That is, the first serving cell and the second serving cell are scheduled cells, and may correspond to the first scheduling cell and the second scheduling cell, respectively. The third serving cell may be a scheduled cell. In the third serving cell, a third subcarrier interval (or μ3) may be used. As described above, the third serving cell may be a different cell from the first serving cell and the second serving cell, and may be cross-carrier scheduled from the first serving cell and the second serving cell. Or, by (method 110), the third serving cell may coincide with one of the first serving cell and the second serving cell.

5 to 8, the third serving cell may coincide with the first serving cell, and the third subcarrier interval may coincide with the first subcarrier interval (ie, μ3 = μ1). In this case, the first serving cell can be self-scheduled from itself and at the same time cross-carrier scheduled from the second serving cell.

Referring to FIG. 5 , a UE may monitor a search space set (SS set) A and a search space set B in a second serving cell for cross-carrier scheduling. In addition, search space sets A and B may be set for the first serving cell, and they may be associated or linked to search space sets A and B, respectively, having the same search space set ID set in the second serving cell. ) can be The UE may consider search space sets A and B to be for cross-carrier scheduling based on the correlation or connection relationship, and monitor search space sets A and B in a second serving cell other than the first serving cell. there is. This can be equally applied to embodiments to be described later. At this time, search space set A and search space set B may belong to different CORESET pools. For example, search space set A and search space set B may belong to a first CORESET pool and a second CORESET pool, respectively. That is, the UE may be configured with a plurality of CORESET pools in the second serving cell, and the plurality of search space sets monitored by the UE for cross-carrier scheduling for the first serving cell may belong to different CORESET pools.

Also, the UE may monitor the search space set C in the first serving cell for self-scheduling. The search space set C may be set not to be associated with the second serving cell and may be set in the first serving cell. The search space set C may not belong to any CORESET pool. That is, the UE may not be configured with a CORESET pool in the first serving cell (at least for the purpose of scheduling the first serving cell). Alternatively, the search space set C may belong to any CORESET pool. That is, the terminal can receive one CORESET pool configured in the first serving cell (for the purpose of scheduling at least the first serving cell), and the set of search spaces monitored by the terminal for self-scheduling is in the one CORESET pool. can belong

In the above case, the maximum number of BD/CCEs in the first serving cell and the second serving cell may be determined by distributing the maximum number of BD/CCEs in any one serving cell. For example, any one serving cell serving as the reference may be a serving cell in which a plurality of CORESET pools are configured. According to this, min(K*M ^max,slot,μ2 , M ^{total,slot,μ2} ) upper limit values based on the second serving cell in which a plurality of CORESET pools are configured and the corresponding subcarrier spacing are assigned to the first serving cell and the second serving cell. can be distributed For example, the UE may up to A*min (K*M ^max,slot,μ2 , M ^{total,slot,μ2} ) for each reference time (eg, each slot of the second serving cell) in the first serving cell. PDCCH candidates can be monitored and up to B*min (K*M ^max,slot,μ2 , M ^{total,slot,μ2} ) for each reference time (eg, each slot of the second serving cell) in the second serving cell PDCCH candidates can be monitored. A and B can be determined by the method described above. In addition, the UE may monitor up to A*min (M ^max,slot,μ2 , M ^{total,slot,μ2} ) PDCCH candidates for each CORESET pool in the second serving cell. At the same time, the UE monitors up to min(M ^max,slot,μ1 , M ^{total,slot,μ1} ) PDCCH candidates for each reference time (eg, each slot of the first serving cell) in the first serving cell. The terminal may select up to min(K*M ^max,slot,μ2 , M ^{total,slot,μ2} ) PDCCH candidates for each reference time (eg, each slot of the second serving cell) in the second serving cell. can be monitored. In addition, the UE may monitor up to min(M ^max,slot,μ2 , M ^{total,slot,μ2} ) PDCCH candidates for each CORESET pool in the second serving cell.

Alternatively, the reference serving cell may be a serving cell in which a CORESET pool is not configured. In this case, the first serving cell and the second serving cell and the second serving cell in which the CORESET pool is not configured have the same min (K*M ^max,slot,μ1 , M ^{total,slot,μ1} ) upper limit values based on the first serving cell and the corresponding subcarrier interval. It can be distributed to serving cells. For example, the terminal monitors up to A*min (M ^max,slot,μ1 , M ^{total,slot,μ1} ) PDCCH candidates for each reference time (eg, each slot of the first serving cell) in the first serving cell. In the second serving cell, up to B*min (M ^{max, slot, μ 1} , M ^{total, slot, μ 1} ) PDCCH candidates can be monitored for each reference time (eg, each slot of the first serving cell). . A and B can be determined by the method described above. In addition, the UE can monitor up to N PDCCH candidates for each CORESET pool in the second serving cell. Here, N may be determined as a value that does not exceed B*min (M ^{max, slot, μ 1} , M ^{total, slot, μ 1} ). At the same time, the terminal can monitor up to min (M ^{max, slot, μ 1} , M ^{total, slot, μ 1} ) PDCCH candidates for each reference time (eg, each slot of the first serving cell) in the first serving cell, , The terminal may monitor up to min(K*M ^max,slot,μ2 , M ^{total,slot,μ2} ) PDCCH candidates for each reference time (eg, each slot of the second serving cell) in the second serving cell. . In addition, the UE may monitor up to min(M ^max,slot,μ2 , M ^{total,slot,μ2} ) PDCCH candidates for each CORESET pool in the second serving cell. Alternatively, the reference serving cell may be determined by cell IDs of serving cells, subcarrier intervals, presence or absence of PCell (or PSCell), and the like. In addition, when one of the cells to be scheduled is a scheduled cell, a cell that is simultaneously scheduled as well as a cell that is scheduled, that is, a cell in which self-scheduling is performed may be determined as a reference serving cell.

In a method different from the above method, the maximum number of BD/CCEs in the first serving cell and the second serving cell may be determined by distributing the maximum number of BD/CCEs in the scheduled cell. For example, M ^max,slot,μ3 or min(M ^max,slot,μ3 , M ^{total,slot,μ3} ) upper limit values based on the scheduled cell and the corresponding subcarrier interval are assigned to the first serving cell and the second serving cell. It can be distributed based on the weights A and B.

Referring to FIG. 6 , the terminal may monitor search space set A and search space set B in the first serving cell for self-scheduling. In addition, the UE may monitor the search space set C in the second serving cell for cross-carrier scheduling. Search space set A and search space set B may belong to the first CORESET pool and the second CORESET pool, respectively. That is, the UE may be configured with a plurality of CORESET pools in the first serving cell, and the plurality of search space sets monitored by the UE for self-scheduling for the first serving cell may belong to different CORESET pools. On the other hand, the search space set C may not belong to any CORESET pool. That is, the UE may not be configured with a CORESET pool in the second serving cell (at least for the purpose of cross-carrier scheduling for the first serving cell). Alternatively, the search space set C may belong to any CORESET pool. That is, the terminal can receive one CORESET pool (for the purpose of cross-carrier scheduling for at least the first serving cell) in the second serving cell, and the set of search spaces monitored by the terminal for cross-carrier scheduling is the above 1 can belong to CORESET pools. In this case, the maximum number of BDs and CCEs that can be monitored or processed by the UE in the first serving cell and the second serving cell may be determined by the above method.

Referring to FIG. 7 , the terminal may receive search space sets A, B, and C in the same manner as in the second embodiment of FIG. 6 and monitor them for scheduling of the first serving cell. In addition to this, the UE may monitor the search space set D in the second serving cell. In this case, the search space set D may be monitored for scheduling of a serving cell (eg, a second serving cell or another serving cell) other than the first serving cell. The UE may be configured with a plurality of CORESET pools in the second serving cell. However, all search space set(s) monitored for scheduling of the first serving cell in the second serving cell (ie, search space set C) may belong to only one CORESET pool (ie, the third CORESET pool). In this case, the maximum number of BDs and CCEs that can be monitored or processed by the UE in the first serving cell and the second serving cell may be determined by the above method.

As a method different from the above-described method, when (method 100) is used, a method in which configuration of a plurality of CORESET pools is equally applied to all of a plurality of scheduling cells may be considered. According to this, the terminal may not expect to be configured to monitor a plurality of CORESET pools only in some serving cells among a plurality of scheduling cells, as in the embodiments of FIGS. 5 to 7 . The terminal may expect that a plurality of CORESET pools are configured in all of the plurality of scheduling cells or that a plurality of CORESET pools (or CORESET pools) are not configured in all of the plurality of scheduling cells.

Referring to FIG. 8 , a plurality of CORESET pools may be configured in both a first serving cell and a second serving cell, which are a plurality of scheduling cells. The UE may monitor search space set A and search space set B in the first serving cell for self-scheduling, and may monitor search space set C and search space set D in the second serving cell for cross-carrier scheduling. . In the first serving cell, the search space set A and the search space set B may respectively belong to different CORESET pools, that is, the first CORESET pool and the second CORESET pool. Also, in the second serving cell, the search space set C and the search space set D may belong to different CORESET pools, that is, a third CORESET pool and a fourth CORESET pool, respectively. Search space sets monitored by the UE for scheduling of the first serving cell may correspond to a plurality of CORESET pools in each of the first serving cell and the second serving cell.

Even in this case, the number of BDs and CCEs that can be maximally monitored or processed by the UE in the first serving cell and the second serving cell can be determined by the method described above. For example, a BD/CCE upper limit determined based on any one of the first serving cell and the second serving cell and the corresponding subcarrier interval may be distributed with a weight applied to the first serving cell and the second serving cell. . Alternatively, the BD/CCE upper limit value determined based on the scheduled cell and the corresponding subcarrier interval may be distributed with a weight applied to the first serving cell and the second serving cell. However, in this case, an asymmetry problem of BD/CCE capacity between serving cells due to a weight K considering multiple TRP transmissions may not occur.

In the above embodiment, CORESET pools may be independently configured in the first serving cell and the second serving cell. Setting information (eg, TCI status, QCL assumption, etc.) for monitoring the first CORESET pool and the second CORESET pool is set information for monitoring the third CORESET pool and the fourth CORESET pool (eg, TCI status, QCL assumption, etc.) assumptions, etc.) can be set independently. Alternatively, CORESET pools configured in the first serving cell and the second serving cell may have correlation with each other. For example, the UE may be configured to apply the same TCI state or QCL assumption to CORESET pools configured in the first serving cell and the second serving cell. To this end, a method in which a CORESET pool is set for a serving cell group may be applied. For example, configuration information of the CORESET pool may include cell IDs for a plurality of serving cells, and the same CORESET pool configuration may be applied to the plurality of serving cells. At this time, CORESET pools having correlation with each other may have the same ID. For example, a CORESET pool having a first serving cell ID of 0 and a CORESET pool having a second serving cell ID 0 may be associated with each other or may share the same configuration parameter(s).

In a method different from the above-described method, when (method 100) is used, a method of restricting a plurality of CORESET pools from being set in any serving cell among a plurality of scheduling cells may be used. That is, cross-carrier scheduling by (method 100) may not be used simultaneously with the above-described multiple TRP transmission method.

In the methods described above, a serving cell may correspond to a bandwidth portion. That is, according to (method 100), one scheduled bandwidth portion may be scheduled by a plurality of scheduling bandwidth portions. Each bandwidth part may correspond to each serving cell. Also, multiple bandwidth portions may belong to the same serving cell. For example, multiple scheduling bandwidth portions may belong to the same serving cell. Simultaneously or separately, the scheduled bandwidth portion may belong to the same serving cell as the scheduling bandwidth portion(s). According to (method 100), scheduling may be performed using a plurality of bandwidth parts within one serving cell.

The operation of the method according to the embodiment of the present invention can be implemented as a computer readable program or code on a computer readable recording medium. A computer-readable recording medium includes all types of recording devices in which information that can be read by a computer system is stored. In addition, computer-readable recording media may be distributed to computer systems connected through a network to store and execute computer-readable programs or codes in a distributed manner.

In addition, the computer-readable recording medium may include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, and flash memory. The program command may include high-level language codes that can be executed by a computer using an interpreter or the like as well as machine code generated by a compiler.

Although some aspects of the invention have been described in the context of an apparatus, it may also represent a description according to a corresponding method, where a block or apparatus corresponds to a method step or feature of a method step. Similarly, aspects described in the context of a method may also be represented by a corresponding block or item or a corresponding feature of a device. Some or all of the method steps may be performed by (or using) a hardware device such as, for example, a microprocessor, programmable computer or electronic circuitry. In some embodiments, at least one or more of the most important method steps may be performed by such a device.

In embodiments, a programmable logic device (eg, a field programmable gate array) may be used to perform some or all of the functions of the methods described herein. In embodiments, a field-programmable gate array may operate in conjunction with a microprocessor to perform one of the methods described herein. Generally, methods are preferably performed by some hardware device.

Although the above has been described with reference to the preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention described in the claims below. You will understand that you can.

Claims (1)

A method of operating a terminal in a carrier aggregation environment in which a first serving cell and a second serving cell are aggregated,
Blind decoding first PDCCH candidates for performing scheduling on the first serving cell in the first serving cell; and
Blind decoding second PDCCH candidates for performing scheduling on the first serving cell and third PDCCH candidates for scheduling on the second serving cell in the second serving cell;
The upper limit of the number of the first PDCCH candidates and the upper limit of the number of the second PDCCH candidates are determined by a first subcarrier interval of a bandwidth part activated in the first serving cell in association with each other, and the number of the third PDCCH candidates The upper limit value of is determined by the second subcarrier spacing of the activated bandwidth portion of the second serving cell, and the number of serving cells corresponding to the first subcarrier spacing is the same regardless of the blind decoding operation for the second PDCCH candidates. determined by the terminal,
How the terminal operates.

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