Patent Description:
Wireless access systems have been widely deployed to provide various types of communication services such as voice or data. In general, a wireless access system is a multiple access system that supports communication of multiple users by sharing available system resources (a bandwidth, transmission power, etc.) among them. For example, multiple access systems include a code division multiple access (CDMA) system, a frequency division multiple access (FDMA) system, a time division multiple access (TDMA) system, an orthogonal frequency division multiple access (OFDMA) system, and a single carrier frequency division multiple access (SC-FDMA) system.

The document ("<NPL>) discloses that a UE can be provided with at least two groups of search space sets for PDCCH, search space sets that are not part of the configured groups (e.g., a common search space set) will always be monitored by the UE regardless of the search space set indication, and search space set groups for the purpose of search space set group switching are configurable per BWP.

The document ("<NPL>) discloses that a UE can be provided with a group index for a respective search space set by searchSpaceGroupldList-r16 for PDCCH monitoring on a serving cell indicated by searchSpaceSwitchingGroup-r16.

Provided are a method and apparatus for efficiently performing a wireless signal transmission and reception process.

According to the present disclosure, a wireless signal may be efficiently transmitted and received in a wireless communication system.

The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the present disclosure and together with the description serve to explain the principle of the present disclosure.

The following technology may be used in various wireless access systems such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and so on. CDMA may be implemented as a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented as a radio technology such as global system for mobile communications (GSM)/general packet radio service (GPRS)/enhanced data rates for GSM evolution (EDGE). OFDMA may be implemented as a radio technology such as institute of electrical and electronics engineers (IEEE) <NUM> (wireless fidelity (Wi-Fi)), IEEE <NUM> (worldwide interoperability for microwave access (WiMAX)), IEEE <NUM>, evolved UTRA (E-UTRA), and so on. UTRA is a part of universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) using E-UTRA, and LTE-advanced (LTE-A) is an evolution of 3GPP LTE. 3GPP new radio or new radio access technology (NR) is an evolved version of 3GPP LTE/LTE-A.

As more and more communication devices require larger communication capacities, the need for enhanced mobile broadband communication relative to the legacy radio access technologies (RATs) has emerged. Massive machine type communication (MTC) providing various services to inter-connected multiple devices and things at any time in any place is one of significant issues to be addressed for next-generation communication. A communication system design in which services sensitive to reliability and latency are considered is under discussion as well. As such, the introduction of the next-generation radio access technology (RAT) for enhanced mobile broadband communication (eMBB), massive MTC (mMTC), and ultra-reliable and low latency communication (URLLC) is being discussed. For convenience, this technology is called NR or New RAT in the present disclosure.

While the following description is given in the context of a 3GPP communication system (e.g., NR) for clarity, the technical spirit of the present disclosure is not limited to the 3GPP communication system.

In a wireless access system, a user equipment (UE) receives information from a base station (BS) on DL and transmits information to the BS on UL. The information transmitted and received between the UE and the BS includes general data and various types of control information. There are many physical channels according to the types/usages of information transmitted and received between the BS and the UE.

<FIG> illustrates physical channels and a general signal transmission method using the physical channels in a 3GPP system.

When a UE is powered on or enters a new cell, the UE performs initial cell search (S101). The initial cell search involves acquisition of synchronization to a BS. For this purpose, the UE receives a synchronization signal block (SSB) from the BS. The SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). The UE synchronizes its timing to the BS and acquires information such as a cell identifier (ID) based on the PSS/SSS. Further, the UE may acquire information broadcast in the cell by receiving the PBCH from the BS. During the initial cell search, the UE may also monitor a DL channel state by receiving a downlink reference signal (DL RS).

Subsequently, to complete connection to the BS, the UE may perform a random access procedure with the BS (S103 to S106). Specifically, the UE may transmit a preamble on a physical random access channel (PRACH) (S103) and may receive a PDCCH and a random access response (RAR) for the preamble on a PDSCH corresponding to the PDCCH (S104). The UE may then transmit a physical uplink shared channel (PUSCH) by using scheduling information in the RAR (S105), and perform a contention resolution procedure including reception of a PDCCH and a PDSCH signal corresponding to the PDCCH (S106).

After the above procedure, the UE may receive a PDCCH and/or a PDSCH from the BS (S107) and transmit a physical uplink shared channel (PUSCH) and/or a physical uplink control channel (PUCCH) to the BS (S108), in a general UL/DL signal transmission procedure. Control information that the UE transmits to the BS is generically called uplink control information (UCI). The UCI includes a hybrid automatic repeat and request acknowledgement/negative acknowledgement (HARQ-ACK/NACK), a scheduling request (SR), channel state information (CSI), and so on. The CSI includes a channel quality indicator (CQI), a precoding matrix index (PMI), a rank indication (RI), and so on. In general, UCI is transmitted on a PUCCH. However, if control information and data should be transmitted simultaneously, the control information and the data may be transmitted on a PUSCH. In addition, the UE may transmit the UCI aperiodically on the PUSCH, upon receipt of a request/command from a network.

<FIG> illustrates a radio frame structure.

In NR, UL and DL transmissions are configured in frames. Each radio frame has a length of <NUM> and is divided into two <NUM>-ms half-frames. Each half-frame is divided into five <NUM>-ms subframes. A subframe is divided into one or more slots, and the number of slots in a subframe depends on a subcarrier spacing (SCS). Each slot includes <NUM> or <NUM> OFDM(A) symbols according to a cyclic prefix (CP). When a normal CP is used, each slot includes <NUM> OFDM symbols. When an extended CP is used, each slot includes <NUM> OFDM symbols. A symbol may include an OFDM symbol (or a CP-OFDM symbol) and an SC-FDMA symbol (or a discrete Fourier transform-spread-OFDM (DFT-s-OFDM) symbol).

Table <NUM> exemplarily illustrates that the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary according to SCSs in a normal CP case.

Table <NUM> illustrates that the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary according to SCSs in an extended CP case.

The frame structure is merely an example, and the number of subframes, the number of slots, and the number of symbols in a frame may be changed in various manners.

In the NR system, different OFDM(A) numerologies (e.g., SCSs, CP lengths, and so on) may be configured for a plurality of cells aggregated for one UE. Accordingly, the (absolute time) duration of a time resource (e.g., a subframe, a slot, or a transmission time interval (TTI)) (for convenience, referred to as a time unit (TU)) composed of the same number of symbols may be configured differently between the aggregated cells. A symbol may include an OFDM symbol (or a CP-OFDM symbol) and an SC-FDMA symbol (or a discrete Fourier transform-spread-OFDM (DFT-s-OFDM) symbol).

<FIG> illustrates a resource grid during the duration of one slot. A slot includes a plurality of symbols in the time domain. For example, one slot includes <NUM> symbols in a normal CP case and <NUM> symbols in an extended CP case. A carrier includes a plurality of subcarriers in the frequency domain. A resource block (RB) may be defined by a plurality of (e.g., <NUM>) consecutive subcarriers in the frequency domain. A bandwidth part (BWP) may be defined by a plurality of consecutive (physical) RBs ((P)RBs) in the frequency domain and correspond to one numerology (e.g., SCS, CP length, and so on). A carrier may include up to N (e.g., <NUM>) BWPs. Data communication may be conducted in an active BWP, and only one BWP may be activated for one UE. Each element in a resource grid may be referred to as a resource element (RE), to which one complex symbol may be mapped.

<FIG> illustrates a structure of a slot. In the NR system, a frame has a self-contained structure in which a DL control channel, DL or UL data, a UL control channel, and the like may all be contained in one slot. For example, the first N symbols (hereinafter, DL control region) in the slot may be used to transmit a DL control channel (e.g., PDCCH), and the last M symbols (hereinafter, UL control region) in the slot may be used to transmit a UL control channel (e.g., PUCCH). N and M are integers greater than or equal to <NUM>. A resource region (hereinafter, a data region) that is between the DL control region and the UL control region may be used for DL data (e.g., PDSCH) transmission or UL data (e.g., PUSCH) transmission. The GP provides a time gap for the BS and UE to transition from the transmission mode to the reception mode or from the reception mode to the transmission mode. Some symbols at the time of DL-to-UL switching in a subframe may be configured as the GP.

The PDCCH delivers DCI. For example, the PDCCH (i.e., DCI) may carry information about a transport format and resource allocation of a DL shared channel (DL-SCH), resource allocation information of an uplink shared channel (UL-SCH), paging information on a paging channel (PCH), system information on the DL-SCH, information on resource allocation of a higher-layer control message such as an RAR transmitted on a PDSCH, a transmit power control command, information about activation/release of configured scheduling (CS), and so on. The DCI includes a cyclic redundancy check (CRC). The CRC is masked with various identifiers (IDs) (e.g. a radio network temporary identifier (RNTI)) according to an owner or usage of the PDCCH. For example, if the PDCCH is for a specific UE, the CRC is masked by a UE ID (e.g., cell-RNTI (C-RNTI)). If the PDCCH is for a paging message, the CRC is masked by a paging-RNTI (P-RNTI). If the PDCCH is for system information (e.g., a system information block (SIB)), the CRC is masked by a system information RNTI (SI-RNTI). When the PDCCH is for an RAR, the CRC is masked by a random access-RNTI (RA-RNTI).

<FIG> illustrates an exemplary PDCCH transmission/reception procedure.

Referring to <FIG>, a BS may transmit a control resource set (CORESET) configuration to a UE (S502). A CORESET is defined as a set of resource element groups (REGs) with a given numerology (e.g., an SCS, a CP length, and so on). An REG is defined by one OFDM symbol and one (P)RB. A plurality of CORESETs for one UE may overlap with each other in the time/frequency domain. A CORESET may be configured by system information (e.g., a master information block (MIB)) or UE-specific higher-layer signaling (e.g., radio resource control (RRC) signaling). The UE-specific RRC signaling may include, for example, an RRC setup message, BWP configuration information, and so on. Specifically, the CORESET configuration may include the following information/fields.

Further, the BS may transmit a PDCCH search space (SS) configuration to the UE (S504). A PDCCH SS set includes PDCCH candidates. A PDCCH candidate is CCE(s) that the UE monitors to receive/detect a PDCCH. The monitoring includes blind decoding (BD) of PDCCH candidates. One PDCCH (candidate) includes <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> CCEs according to an aggregation level (AL). One CCE includes <NUM> REGs. Each CORESET configuration is associated with one or more SSs, and each SS is associated with one CORESET configuration. One SS is defined based on one SS configuration, and the SS configuration may include the following information/fields.

Subsequently, the BS may generate a PDCCH and transmit the PDCCH to the UE (S506), and the UE may monitor PDCCH candidates in one or more SSs to receive/detect the PDCCH (S508). An occasion (e.g., time/frequency resources) in which the UE is to monitor PDCCH candidates is defined as a PDCCH (monitoring) occasion. The UE may determine a PDCCH monitoring occasion on an active DL BWP in a slot according to a PDCCH monitoring periodicity, a PDCCH monitoring offset, and a PCCH monitoring pattern. One or more PDCCH (monitoring) occasions may be configured in a slot.

Table <NUM> shows the characteristics of each SS.

Table <NUM> exemplarily shows DCI formats transmitted on the PDCCH.

DCI format 0_0 may be used to schedule a TB-based (or TB-level) PUSCH, and DCI format 0_1 may be used to schedule a TB-based (or TB-level) PUSCH or a code block group (CBG)-based (or CBG-level) PUSCH. DCI format 1_0 may be used to schedule a TB-based (or TB-level) PDSCH, and DCI format 1_1 may be used to schedule a TB-based (or TB-level) PDSCH or a CBG-based (or CBG-level) PDSCH (DL grant DCI). DCI format 0_0/0_1 may be referred to as UL grant DCI or UL scheduling information, and DCI format 1_0/1_1 may be referred to as DL grant DCI or DL scheduling information. DCI format 2_0 is used to deliver dynamic slot format information (e.g., a dynamic slot format indicator (SFI)) to a UE, and DCI format 2_1 is used to deliver DL pre-emption information to a UE. DCI format 2_0 and/or DCI format 2_1 may be delivered to a corresponding group of UEs on a group common PDCCH which is a PDCCH directed to a group of UEs.

DCI format 0_0 and DCI format 1_0 may be referred to as fallback DCI formats, whereas DCI format 0_1 and DCI format 1_1 may be referred to as non-fallback DCI formats. In the fallback DCI formats, a DCI size/field configuration is maintained to be the same irrespective of a UE configuration. In contrast, the DCI size/field configuration varies depending on a UE configuration in the non-fallback DCI formats.

CCE-REG mapping is set to one of a non-interleaved CCE-REG mapping type or an interleaved CCE-REG mapping type.

Equation <NUM> represents the resources constituting an SS. Specifically, for SS set s associated with CORESET p, CCE indexes for aggregation level L corresponding to PDCCH candidate ms,nCI of the SS in slot nus,f of the active DL BWP of the serving cell (the value of the CI field, nci) may be given as follows. <MAT> where:.

In NR, a wider UL/DL bandwidth may be supported by aggregating a plurality of UL/DL carriers (i.e., carrier aggregation (CA)). A signal may be transmitted/received over a plurality of carriers by CA. When CA is applied, each carrier (see <FIG>) may be referred to as a component carrier (CC). CCs may be contiguous or non-contiguous in the frequency domain. The bandwidth of each CC may be determined independently. Asymmetric CA is also available, in which the number of UL CCs is different from the number of DL CCs. In NR, radio resources are divided into/managed in cells, and a cell may include one DL CC and zero to two UL CCs. For example, a cell may include (i) only one DL CC, (ii) one DL CC and one UL CC, or (iii) one DL CC and two UL CCs (including one supplementary UL CC). Cells are classified as follows. In the present disclosure, a cell may be interpreted in the context. For example, a cell may mean a serving cell. Further, operations described herein may be applied to each serving cell, unless otherwise specified.

Control information may be configured to be transmitted and received only in a specific cell. For example, UCI may be transmitted only in an SpCell (e.g., PCell). When an SCell allowed for PUCCH transmission (hereinafter, referred to as PUCCH-SCell) is configured, UCI may also be transmitted in the PUCCH-SCell. In another example, the BS may allocate a scheduling cell (set) to reduce the PDCCH BD complexity of the UE. For PDSCH reception/PUSCH transmission, the UE may perform PDCCH detection/decoding only in the scheduling cell. Further, the BS may transmit a PDCCH only in the scheduling cell (set). For example, data (e.g., a PDSCH or a PUSCH) transmitted in one cell (or an active BWP in the cell) (hereinafter, a cell may be replaced with an (active) BWP in the cell) may be scheduled by a PDCCH in the cell (self-carrier scheduling (SCS)). Further, a PDCCH for a DL assignment may be transmitted in cell #<NUM> (i.e., a scheduling cell) and a corresponding PDSCH may be transmitted in cell #<NUM> (i.e., a scheduled cell) (cross-carrier scheduling (CCS)). The scheduling cell (set) may be configured UE-specifically, UE group-specifically, or cell-specifically. The scheduling cell includes an SpCell (e.g., PCell).

For CCS, a carrier indicator field (CIF) is used. The CIF may be disabled/enabled semi-statically by UE-specific (or UE group-specific) higher-layer signaling (e.g., RRC signaling). The CIF is an x-bit field (e.g., x=<NUM>) of a PDCCH (i.e., DCI) and may be used to indicate the (serving) cell index of a scheduled cell.

<FIG> illustrates exemplary scheduling in the case of multi-cell aggregation. Referring to <FIG>, it is assumed that three cells are aggregated. When the CIF is disabled, only a PDCCH that schedules a PDSCH/PUSCH in each cell may be transmitted in the cell (SCS). On the contrary, when the CIF is enabled by UE-specific (or UE group-specific or cell-specific) higher-layer signaling, and cell A is configured as a scheduling cell, a PDCCH that schedules a PDSCH/PUSCH in another cell (i.e., a scheduled cell) as well as a PDCCH that schedules a PDSCH/PUSCH in cell A may be transmitted in cell A (CCS). In this case, no PDCCH that schedules a PDSCH/PUSCH in cell B/C is transmitted in cell B/C.

<FIG> illustrates an exemplary wireless communication system supporting an unlicensed band applicable to the present disclosure. In the following description, a cell operating in a licensed band (L-band) is defined as an L-cell, and a carrier of the L-cell is defined as a (DL/UL) LCC. A cell operating in an unlicensed band (U-band) is defined as a U-cell, and a carrier of the U-cell is defined as a (DL/UL) UCC. The carrier/carrier-frequency of a cell may refer to the operating frequency (e.g., center frequency) of the cell. A cell/carrier (e.g., CC) is commonly called a cell.

When carrier aggregation is supported, one UE may use a plurality of aggregated cells/carriers to exchange a signal with the BS. When one UE is configured with a plurality of CCs, one CC may be set to a primary CC (PCC), and the remaining CCs may be set to secondary CCs (SCCs). Specific control information/channels (e.g., CSS PDCCH, PUCCH) may be transmitted and received only on the PCC. Data may be transmitted and received on the PCC/SCC. <FIG> shows a case in which the UE and BS exchange signals on both the LCC and UCC (non-standalone (NSA) mode). In this case, the LCC and UCC may be set to the PCC and SCC, respectively. When the UE is configured with a plurality of LCCs, one specific LCC may be set to the PCC, and the remaining LCCs may be set to the SCC. <FIG> corresponds to the LAA of the 3GPP LTE system. <FIG> shows a case in which the UE and BS exchange signals on one or more UCCs with no LCC (standalone (SA) mode). In this case, one of the UCCs may be set to the PCC, and the remaining UCCs may be set to the SCC. Both the NSA mode and SA mode may be supported in the U-band of the 3GPP NR system.

<FIG> illustrates an exemplary method of occupying resources in an unlicensed band. According to regional regulations for an unlicensed band, a communication node should determine whether other communication node(s) is using a channel in the unlicensed band, before signal transmission. Specifically, the communication node may determine whether other communication node(s) is using a channel by performing carrier sensing (CS) before signal transmission. When the communication node confirms that any other communication node is not transmitting a signal, this is defined as confirming clear channel assessment (CCA). In the presence of a CCA threshold predefined by higher-layer signaling (RRC signaling), when the communication node detects energy higher than the CCA threshold in the channel, the communication node may determine that the channel is busy, and otherwise, the communication node may determine that the channel is idle. For reference, the WiFi standard (e.g., <NUM>. 11ac) specifies a CCA threshold of - 62dBm for a non-WiFi signal and a CCA threshold of -82dBm for a WiFi signal. When determining that the channel is idle, the communication node may start signal transmission in a UCell. The above-described series of operations may be referred to as a listen-before-talk (LBT) or channel access procedure (CAP). LBT and CAP may be interchangeably used. After performing the CAP, the BS/UE may perform transmission on the channel (Channel occupancy). The Channel Occupancy Time (COT) represents the total time for which the BS/UE and a BS/UE(s) sharing the channel occupancy may continue/perform transmission(s) on the channel after the BS/UE performs the CAP. The COT may be shared for transmission between the BS and the corresponding UE(s).

In Europe, two LBT operations are defined: frame based equipment (FBE) and load based equipment (LBE). In FBE, one fixed frame is made up of a channel occupancy time (e.g., <NUM> to <NUM>), which is a time period during which once a communication node succeeds in channel access, the communication node may continue transmission, and an idle period corresponding to at least <NUM>% of the channel occupancy time, and CCA is defined as an operation of observing a channel during a CCA slot (at least <NUM>) at the end of the idle period. The communication node performs CCA periodically on a fixed frame basis. When the channel is unoccupied, the communication node transmits during the channel occupancy time, whereas when the channel is occupied, the communication node defers the transmission and waits until a CCA slot in the next period.

In LBE, the communication node may set q ∈ {<NUM>, <NUM>,. , <NUM>} and then perform CCA for one CCA slot. When the channel is unoccupied in the first CCA slot, the communication node may secure a time period of up to (<NUM>/<NUM>)q ms and transmit data in the time period. When the channel is occupied in the first CCA slot, the communication node randomly selects N ∈ {<NUM>, <NUM>,. , q}, stores the selected value as an initial value, and then senses a channel state on a CCA slot basis. Each time the channel is unoccupied in a CCA slot, the communication node decrements the stored counter value by <NUM>. When the counter value reaches <NUM>, the communication node may secure a time period of up to (<NUM>/<NUM>)q ms and transmit data.

In the 3GPP Rel-<NUM> NR system, a plurality of BWPs (e.g., up to <NUM> BWPs) may be configured in a cell, and only one of the BWPs may be activated. In addition, one or more SS sets may be linked to a CORESET, and a maximum of <NUM> SS sets may be configured per BWP. In each SS set, not only the time resource (period (in units of slots), an offset (units of slots), and an in-slot interval (in-slot position) in which the linked CORESET is positioned, but also a DCI format and the number of PDCCH candidates per AL may be configured.

In the unlicensed band, the CAP success time of the BS may not be predicted. Accordingly, it may be advantageous in terms of efficient channel occupancy of the BS to configure a short PDCCH monitoring period or time instance interval. However, configuring the PDCCH monitoring period or time instance interval to be short may increase power consumption of the UE. Accordingly, configuring a relatively long PDCCH monitoring period (or SS set period) or time instance interval within the COT acquired by the BS may be advantageous in terms of the UE power consumption. Therefore, the PDCCH monitoring period, that is, the monitoring pattern set in the SS set, may be configured differently depending on whether it belongs to the COT of the BS.

To support this configuration, RRC signaling for grouping SS sets has been introduced in 3GPP Rel-<NUM> NR-U. In a slot, PDCCH monitoring may be allowed for only one SS set group. SS sets for which PDCCH monitoring is performed may be switched in units of SS set groups (hereinafter, this operation is referred to as SS set group switching or SS (set) switching). An SS set group for which PDCCH monitoring is performed may be indicated by DCI signaling or the like, or may be recognized by the UE according to the COT structure of the BS identified by the UE.

<FIG> illustrates SS switching. Referring to <FIG>, one or more SS set groups (simply referred to as groups) may be configured for SS sets configured in a BWP in a cell (e.g., cell #<NUM>). For example, two groups may be configured. When five SS sets (e.g., SS sets #<NUM> to #<NUM>) are configured in a BWP, the groups may be configured as follows.

There may be an SS set that does not belong to any group may exist, such as SS set #<NUM>/<NUM>. Also, there may be an SS set belonging to every group, such as SS set #<NUM>. The UE may perform PDCCH monitoring for only one group among a plurality of groups in a slot, and groups for which PDCCH monitoring is performed may be switched based on an event.

Specifically, based on a first switching condition (hereinafter, a first condition) being triggered, switching from group #<NUM> to group #<NUM> may be performed. The first condition may include all or part of the following conditions:.

When the first condition is satisfied, PDDCH monitoring for group #<NUM> may be stopped and PDDCH monitoring for group #<NUM> may be started/initiated at the first slot boundary after at least P1 symbols,. P1 is an integer greater than or equal to <NUM>, and may be a positive integer.

Also, based on a second switching condition (hereinafter, a second condition) being triggered, switching from group #<NUM> to group #<NUM> may be performed. The second condition may include all or part of the following conditions:.

When the second condition is satisfied, PDDCH monitoring for group #<NUM> may be stopped at the first slot boundary and PDDCH monitoring for group #<NUM> may be started/initiated after at least P2 symbols. P2 is an integer greater than or equal to <NUM>, and may be a positive integer.

Table <NUM> shows some modifications based on TS <NUM> v16.

A plurality of cells is configured as a cell group (hereinafter, CGR) for SS switching. In this case, the SS switching operation is equally applied to the cell group. For example, a plurality of SS set groups may be set in each of cell #<NUM> and cell #<NUM>. Cell #<NUM> and cell #<NUM> may be configured as a CGR. In this case, when the SS switching condition is satisfied for one cell, SS switching may be performed even for the other cell.

<FIG> illustrates SS switching performed when a CGR for SS switching is configured. Referring to <FIG>, one or more SS set groups (simply, groups) may be configured for SS sets configured in a BWP in a cell (e.g., cell #<NUM>). For example, two groups may be configured. When five SS sets (e.g., SS sets #<NUM> to #<NUM>) are configured in a BWP, the groups may be configured as follows:.

Similarly, one or more groups may be configured for SS sets configured in a BWP in the other cell (e.g., cell #<NUM>) as follows:.

When cells #<NUM>/#<NUM> are configured as a CGR, switching from group #<NUM> to group #<NUM> may be performed for both cells based on the first condition being triggered. When the first condition is satisfied, the UE may perform PDCCH monitoring in an SS set linked to a group to which switching is actually at the first slot boundary that follows at least P1 symbols (after a reference time). P1 is an integer greater than or equal to <NUM>, and may be a positive integer. Also, based on the second condition being triggered, switching from group #<NUM> to group #<NUM> may be performed for both cells. When the second condition is satisfied, the UE may perform PDCCH monitoring in an SS set linked to a group to which switching is actually at the first slot boundary that follows at least P2 symbols (after the reference time). P2 is an integer greater than or equal to <NUM>, and may be a positive integer.

<FIG> illustrates a case where all cells in a CGR have the same numerology (e.g., SCS (see Table <NUM>)). In this case, since the cells have the same slot/symbol duration, and accordingly there is no difference between the cells in terms of the time to apply SS switching determined based on a symbol/slot. However, when different numerologies are configured in the CGR (namely, when cells/BWPs have different numerologies), the slot/symbol duration may differ between the cell, and accordingly the time to apply SS switching may vary depending on a cell whose symbol/slot forms the basis of determination of the time.

Hereinafter, a method of determining an SS switching time when the numerology differs between cells configured in a CGR (or between intra-cell (active) BWPs) is proposed. Here, the CGR may include a plurality of cells to which SS switching is applied. In the following description, when a plurality of BWPs is configured in a cell, the cell may be replaced with an (active) BWP in the cell. In addition, SS switching may be used not only in the unlicensed band, but also in the licensed band.

[Method #<NUM>] Setting a reference time at which the first/second condition is triggered (or when switching is performed on the first slot (boundary) after at least P1/P2 symbols based on the first/second condition being triggered, configuring a reference symbol when P1=P2=<NUM>).

When the first (or second) condition is triggered due to the PDCCH detected in cell #<NUM> in a CGR, the last symbol (e.g., symbol index N) for the PDCCH (or the CORESET including the PDCCH) on cell #<NUM> ) may be defined as a reference time. When cell #<NUM> and cell #<NUM> belonging to the same CGR have the same numerology (e.g., SCS), the reference times may be aligned with the same symbol index (see <FIG>). However, when the numerology differs between the cells (or BWPs) belonging to the same CGR, the reference times may not be aligned. Considering that configuring the same SS set switching time for the cells may reduce complexity in terms of the PDCCH monitoring operation of the UE, a rule needs to be established such that the reference times are aligned among the cells in the CGR.

As a method, a specific (e.g., first or last) symbol in cell #<NUM> overlapping with symbol index N in cell #<NUM> may be defined as a reference time for cell #<NUM>. As an example, when there are two symbols M and M+<NUM> in <NUM> SCS cell #<NUM> coexisting (i.e., overlapping in time) with symbol n in <NUM> SCS cell #<NUM>, the last symbol index, symbol #M+<NUM>, may be defined as the reference symbol for inter-cell alignment.

This method may be equally applied to determining a reference time for determining a PDCCH detection time when a timer operation starts due to PDCCH detection (which is one of the conditions for triggering the second condition). For example, when the last symbol in cell #<NUM> for a certain PDCCH (transmitted in cell #<NUM>) (or a CORESET linked to the PDCCH) is symbol #N, the reference time for cell #<NUM> may be symbol #N, and a specific (e.g., first or last) symbol in cell #<NUM> overlapping with symbol #N in cell #<NUM> may be defined as a reference time for cell #<NUM>. The timer operation may be started at the reference time.

[Method #<NUM>] A method for determining the first slot (boundary) when switching is performed on the first slot (boundary) after at least P1/P2 symbols based on the first/second condition being triggered.

When the first (or second) condition is triggered, PDCCH monitoring through an SS set associated with the switched group is performed/started from the UE perspective on the first slot (boundary) following at least P1 (or P2) symbols (after the reference time). In the case where cell #<NUM> and cell #<NUM> belonging to the same CGR have the same numerology, the first slots (slot boundaries) may be aligned at the same time (see <FIG>). Here, the numerology may include a symbol/slot duration and SCS, and reference may be made to Table <NUM>. Referring to Table <NUM> and <FIG>, the symbol/slot duration varies based on the SCS. Accordingly, when cells (or BWPs) belonging to the same CGR have different numerologies, the corresponding time points may not be aligned. <FIG> illustrates a case where the numerology differs between cells (or BWPs) belonging to a CGR. Referring to <FIG>, it is assumed that the SCS of cell #<NUM> is 2X kHz and the SCS of cell #<NUM> is X kHz. In this case, the duration (or period) of the symbol/slot of cell #<NUM> is configured to be shorter than the duration of the symbol/slot of cell #<NUM>. Accordingly, considering that configuring the same SS set switching time for the cells may reduce complexity in terms of the PDCCH monitoring operation of the UE, a rule needs to be established such that the times are aligned among the cells in the CGR.

For example, referring to <FIG>, <FIG> kHz SCS cell #<NUM> may be configured/determined as a reference cell (i.e., the smallest SCS), and the first slot (boundary) (e.g., slot index K) after at least P1 or P2 symbols may be determined based on the numerology corresponding to <NUM> SCS. That is, whether the time corresponding to P1 or P2 symbols has elapsed may be determined based on the <NUM> SCS-based symbol duration. In this case, when slots index L and L+<NUM> in <NUM> SCS cell #<NUM> overlap with slot index K in <NUM> SCS cell #<NUM>, a specific one (e.g., slot index L or slot index L+<NUM>) of the slots It may be determined as the first slot (boundary) in cell # <NUM>. As another example, <NUM> SCS cell #<NUM> may be configured/determined as a reference cell (i.e., the largest SCS), and the first slot (boundary) (e.g., slot index K) after at least P1 or P2 symbols may be determined based thereon. In this case, slot #L in <NUM> SCS cell #<NUM> overlapping with slot index K in <NUM> SCS cell #<NUM> may be determined as the first slot (boundary) in cell #<NUM>. Here, the values of P1 and/or P2 may be set differently for each numerology, as described in Opt2. For example, the values of P1 and/or P2 may be replaced with the value of Pswitch shown in Table <NUM>.

[Method #<NUM>] Setting a timer value corresponding to one of the second conditions.

Considering that numerology may differ among cells (or BWPs) in the CGR, a separate timer value may be set for each cell (or BWP) or numerology by higher layer (e.g., RRC) signaling. However, considering that configuring the same SS set switching time for the cells (or BWPs) in the CGR may reduce complexity in terms of the PDCCH monitoring operation of the UE, a common timer value may be set even when the numerology differs between the cells (or BWP). Accordingly, the timer value may be set independently of the SCS (in a time unit such as, for example, ms), or may be set based on representative numerology (e.g., the number of slots/symbols based on <NUM>; the number of slots/symbols based on the smallest or largest SCS in the CGR; or the number of slots/symbols based on the numerology of a specific representative cell). When the timer value is set based on the representative numerology, the value of the timer may be changed (e.g., decremented by <NUM>) on a slot basis as in the existing cases, and the timer may be operated based on the slot duration corresponding to the SCS.

[Method #<NUM>] In consideration of the UE processing complexity involved when numerology differs between cells (or BWPs), the UE may expect that the same numerology is configured for the cells (or BWPs) belonging to a CGR.

[Method #<NUM>] For a cell in which FBE is configured (or a CGR including the cell in which FBE is configured), a rule may be defined to start monitoring group #<NUM> at the start of every fixed frame period (FFP).

As shown in Table <NUM>, the UE is configured to report the capability it has for the minimum Pswitch value for each SCS. When a specific capability is not reported, it means that the UE supports capability <NUM>. Reporting the specific capability means that the UE supports capability <NUM>. In this regard, the BS may set a value greater than or equal to the minimum Pswitch value corresponding to the UE capability for the UE through higher layer (e.g., RRC) signaling.

When one of the following conditions is triggered during monitoring of the SS sets corresponding to group #<NUM>, the UE may stop monitoring group #<NUM> and start monitoring group #<NUM> after Pswitch symbols from the earliest triggering time:.

Here, when FBE is additionally configured, the following condition may be added to stop monitoring group #<NUM> and start monitoring group #<NUM> at the start of the FFP:.

In other words, when at least one of the following conditions is triggered during monitoring of the SS sets corresponding to group #<NUM>, the UE may stop monitoring group #<NUM> and start monitoring group #<NUM> after Pswitch symbols from the earliest triggering time:.

Here, the FFP may be configured with a periodicity of Tx in every <NUM> frames (e.g., <NUM>). Tx may be one of <NUM>/<NUM>/<NUM>/<NUM>/<NUM>/<NUM>, and may be configured by higher layer (e.g., RRC) signaling. For example, when Tx is set to <NUM>, <NUM> FFPs are configured with a periodicity of <NUM> in every <NUM> frames.

The proposal may be added as a new condition to Table <NUM>. In addition, the values of P1/P2 in the proposal of the present disclosure and Table <NUM> may be replaced with Pswitch of the present method.

[Method #<NUM>] When multiple BWPs are configured for cell #<NUM> belonging to a CGR, no group index value may be set for any SS set(s) configured in BWP#<NUM>, and group index value(s) may be set for some (or all) of the SS sets configured in BWP#<NUM>. In this regard, when BWP switching is performed from BWP#<NUM> to BWP#<NUM>, a proposal is made regarding whether the UE should perform PDCCH monitoring on SS sets corresponding to a group index among the SS sets configured in BWP#<NUM>. Specifically, when the UE is performing PDCCH monitoring on SS sets corresponding to a specific group index for cell(s) belonging to the CGR, other than cell #<NUM>, it may perform BWP switching to BWP #<NUM> of cell #<NUM>, and then perform PDCCH monitoring on SS sets corresponding to a corresponding group index even for cell #<NUM>. Alternatively, when the UE is not performing PDCCH monitoring on SS sets corresponding to a specific group index for all cell(s) belonging to the CGR other than cell #<NUM>, it may perform BWP switching to BWP#<NUM> of cell #<NUM>, and then perform PDCCH monitoring on SS sets corresponding to group index <NUM> (or group index <NUM> or a preset specific group index) for cell #<NUM>.

For example, cell #<NUM> and cell #<NUM> may be configured to belong to the CGR. In this case, the UE may be performing PDCCH monitoring on SS sets corresponding to group #<NUM> in slot #n for an active BWP in cell #<NUM>. In BWP#<NUM> in cell #<NUM>, no group index may be set for any of the SS sets. In BWP#<NUM>, SS set #A may be configured as group #<NUM> and SS set #B may be configured as group #<NUM>. When BWP switching to BWP#<NUM> is indicated/configured by DCI (or timer expiration or RRC signaling) during operation of the UE in BWP#<NUM>, and thus the UE starts to operate in BWP#<NUM> in slot #n, the UE may perform PDCCH monitoring on SS set #B corresponding to group #<NUM> in slot #n for BWP#<NUM> in cell #<NUM>, in consideration of the index of the group operating in cell #<NUM>.

As another example, cell #<NUM> and cell #<NUM> may be configured to belong to the CGR. In this case, for the active BWP in cell #<NUM>, no group index may be set for any SS sets. No group index may be set for any SS sets in BWP#<NUM> in cell #<NUM>. In BWP#<NUM>, SS set #A may be configured as group #<NUM> and SS set #B may be configured as group #<NUM>. When BWP switching to BWP#<NUM> is indicated/configured by DCI (or timer expiration or RRC signaling) during operation of the UE in BWP#<NUM>, and thus the UE starts to operate in BWP#<NUM> in slot #n, the UE may perform PDCCH monitoring on SS set #A corresponding to group #<NUM> (wherein the specific group index may be predefined or set by higher layer signaling) in slot #n for BWP#<NUM> in cell #<NUM>, considering that there is no group index operating in all cells (i.e., cell #<NUM>) in the same CGR.

[Method #1A] Setting a reference time at which the first/second condition is triggered (or when switching is performed on the first slot (boundary) after at least P1/P2 symbols based on the first/second condition being triggered, configuring a reference symbol when P1=P2=<NUM>).

[Method #2A] Determining the first slot (boundary) when switching is performed on the first slot (boundary) after at least P1/P2 symbols based on the first/second condition being triggered.

When the first (or second) condition is triggered, the BS may expect that PDCCH monitoring through an SS set associated with the switched group will be performed/started from the UE perspective on the first slot (boundary) following at least P1 (or P2) symbols (after the reference time). In the case where cell #<NUM> and cell #<NUM> belonging to the same CGR have the same numerology, the first slots (slot boundaries) may be aligned at the same time (see <FIG>). Here, the numerology may include a symbol/slot duration and SCS, and reference may be made to Table <NUM>. Referring to Table <NUM> and <FIG>, the symbol/slot duration varies based on the SCS. Accordingly, when cells (or BWPs) belonging to the same CGR have different numerologies, the corresponding time points may not be aligned. <FIG> illustrates a case where the numerology differs between cells (or BWPs) belonging to a CGR. Referring to <FIG>, it is assumed that the SCS of cell #<NUM> is 2X kHz and the SCS of cell #<NUM> is X kHz. In this case, the duration (or period) of the symbol/slot of cell #<NUM> is configured to be shorter than the duration of the symbol/slot of cell #<NUM>. Accordingly, considering that configuring the same SS set switching time for the cells may reduce complexity in terms of the PDCCH monitoring operation of the UE, a rule needs to be established such that the times are aligned among the cells in the CGR.

For example, referring to <FIG>, <FIG> kHz SCS cell #<NUM> may be configured/determined as a reference cell (i.e., the smallest SCS), and the first slot (boundary) (e.g., slot index K) after at least P1 or P2 symbols may be determined based on the numerology corresponding to <NUM> SCS. That is, whether the time corresponding to P1 or P2 symbols has elapsed may be determined based on the <NUM> SCS-based symbol duration. In this case, when slots #L and #L+<NUM> in <NUM> SCS cell #<NUM> overlap with slot index K in <NUM> SCS cell #<NUM>, a specific one (e.g., slot index L or slot index L+<NUM>) of the slots It may be determined as the first slot (boundary) in cell # <NUM>. As another example, <NUM> SCS cell #<NUM> may be configured/determined as a reference cell (i.e., the largest SCS), and the first slot (boundary) (e.g., slot index K) after at least P1 or P2 symbols may be determined based thereon. In this case, slot index L in <NUM> SCS cell #<NUM> overlapping with slot index K in <NUM> SCS cell #<NUM> may be determined as the first slot (boundary) in cell #<NUM>. Here, the values of P1 and/or P2 may be set differently for each numerology, as described in Opt2. For example, the values of P1 and/or P2 may be replaced with the value of Pswitch shown in Table <NUM>.

[Method #3A] Setting a timer value corresponding to one of the second conditions.

[Method #4A] In consideration of the UE processing complexity involved when numerology differs between cells (or BWPs), the BS may be limited to always configure the same numerology for the cells (or BWPs) belonging to a CGR.

[Method #5A] For a cell in which FBE is configured (or a CGR including the cell in which FBE is configured), a rule may be defined to start monitoring group #<NUM> at the start of every FFP.

When one of the following conditions is triggered while the UE is monitoring the SS sets corresponding to group #<NUM>, the BS may expect that monitoring of group #<NUM> by the UE will be stopped and monitoring of group #<NUM> by the UE will be started after Pswitch symbols from the earliest triggering time:.

Here, when FBE is additionally configured, the following condition may be added to stop monitoring group #<NUM> and start monitoring group #<NUM> at the start of the FFP.

In other words, when at least one of the following conditions is triggered while the UE is monitoring the SS sets corresponding to group #<NUM>, the BS may expect that monitoring of group #<NUM> by the UE will be stopped and monitoring of group #<NUM> by the UE will be started after Pswitch symbols from the earliest triggering time:.

[Method #6A] When multiple BWPs are configured for cell #<NUM> belonging to a CGR, no group index value may be set for any SS set(s) configured in BWP#<NUM>, and group index value(s) may be set for some (or all) of the SS sets configured in BWP#<NUM>. In this regard, when BWP switching is performed from BWP#<NUM> to BWP#<NUM>, a proposal is made regarding whether the UE should perform PDCCH monitoring on SS sets corresponding to a group index among the SS sets configured in BWP#<NUM>. Specifically, when the UE is performing PDCCH monitoring on SS sets corresponding to a specific group index for cell(s) belonging to the CGR, other than cell #<NUM>, the BS may expect that the UE will perform BWP switching to BWP #<NUM> of cell #<NUM>, and then perform PDCCH monitoring on SS sets corresponding to a corresponding group index even for cell #<NUM>. Alternatively, when the UE is not performing PDCCH monitoring on SS sets corresponding to a specific group index for all cell(s) belonging to the CGR other than cell #<NUM>, the BS may expect that the UE will perform BWP switching to BWP#<NUM> of cell #<NUM>, and then perform PDCCH monitoring on SS sets corresponding to group index <NUM> (or group index <NUM> or a preset specific group index) for cell #<NUM>.

For example, cell #<NUM> and cell #<NUM> may be configured to belong to the CGR. In this case, the BS may expect that the UE is performing PDCCH monitoring on SS sets corresponding to group #<NUM> in slot #n for an active BWP in cell #<NUM>. In BWP#<NUM> in cell #<NUM>, no group index may be set for any of the SS sets. In BWP#<NUM>, SS set #A may be configured as group #<NUM> and SS set #B may be configured as group #<NUM>. When BWP switching to BWP#<NUM> is indicated/configured by DCI (or timer expiration or RRC signaling) during operation of the UE in BWP#<NUM>, and thus the UE starts to operate in BWP#<NUM> in slot #n, the UE may perform PDCCH monitoring on SS set #B corresponding to group #<NUM> in slot #n for BWP#<NUM> in cell #<NUM>, in consideration of the index of the group operating in cell #<NUM>.

<FIG> illustrates a PDCCH monitoring operation according to an example of the present disclosure. Referring to <FIG>, a BS may transmit a plurality of pieces of SS set configuration information to a UE (S1502). Here, the SS set configuration information may be provided for each BWP. For a detailed example of the SS set configuration information, reference may be made to the details described with reference to <FIG>. The BS may transmit the SS set group configuration information to the UE (S1502). The SS set group configuration information may include information for additionally setting a group index to indicate an SS set group (hereinafter, group) to which each SS set belongs. The BS may also transmit, to the UE, configuration information about a cell group (CGR) in which an SS switching operation may be applied in common (S1502). Thereafter, the BS may directly informs the UE of a group to which switching is to be performed (e.g., the first/second condition for switching) (S1504). Alternatively, the UE may perform switching commonly/simultaneously for cells belonging to the same CGR when a specific condition is triggered, (S1506). Thereafter, the UE may perform PDCCH monitoring on the SS set corresponding to the switched group (S1508). According to the PDCCH monitoring result, the UE may receive the PDCCH and perform an operation accordingly. For example, when the PDCCH includes scheduling information, the UE may receive a PDSCH or transmit a PUSCH based on the PDCCH.

Here, in order to perform group switching on cells belonging to the CGR, various methods proposed in the present disclosure (Methods #<NUM> to #<NUM>/#1A to #6A) may be used. For simplicity, each of the methods has been described separately, but they may be combined as long as they do not contradict/conflict with each other.

For example, Opt1 of method #<NUM> proposes a timing for performing SS switching when a switching condition is satisfied. Specifically, the first slot that follows at least P1/P2 symbols after a reference time may be defined as the SS switching time, and the P1/P2 symbols may be determined based on cell (representative) numerology (e.g., the smallest SCS). For example, the cell (representative) numerology may include a symbol duration that is based on the smallest SCS in the CGR. In addition, P1/P2 may be replaced with the Pswitch of method #<NUM>, and the value thereof may vary among SCSs. In addition, as for the timer used to determine the switching condition, a common timer value may be set even when the numerology differs between the cells (or BWPs) according to method #<NUM>. For example, the timer may be configured to operate based on the representative numerology (e.g., the number of slots/symbols based on the smallest SCS in the CGR). Other methods may be combined in a similar manner.

The various descriptions, functions, procedures, proposals, methods, and/or operation flowcharts of the present disclosure described herein may be applied to, but not limited to, various fields requiring wireless communication/connectivity (e.g., <NUM>) between devices.

More specific examples will be described below with reference to the drawings. In the following drawings/description, like reference numerals denote the same or corresponding hardware blocks, software blocks, or function blocks, unless otherwise specified.

Referring to <FIG>, the communication system <NUM> applied to the present disclosure includes wireless devices, BSs, and a network. A wireless device is a device performing communication using radio access technology (RAT) (e.g., <NUM> NR (or New RAT) or LTE), also referred to as a communication/radio/<NUM> device. The wireless devices may include, not limited to, a robot 100a, vehicles 100b-<NUM> and 100b-<NUM>, an extended reality (XR) device 100c, a hand-held device 100d, a home appliance 100e, an IoT device 100f, and an artificial intelligence (AI) device/server <NUM>. For example, the vehicles may include a vehicle having a wireless communication function, an autonomous driving vehicle, and a vehicle capable of vehicle-to-vehicle (V2V) communication. Herein, the vehicles may include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device may include an augmented reality (AR)/virtual reality (VR)/mixed reality (MR) device and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) mounted in a vehicle, a television (TV), a smartphone, a computer, a wearable device, a home appliance, a digital signage, a vehicle, a robot, and so on. The hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or smart glasses), and a computer (e.g., a laptop). The home appliance may include a TV, a refrigerator, a washing machine, and so on. The IoT device may include a sensor, a smartmeter, and so on. For example, the BSs and the network may be implemented as wireless devices, and a specific wireless device 200a may operate as a BS/network node for other wireless devices.

An AI technology may be applied to the wireless devices 100a to 100f, and the wireless devices 100a to 100f may be connected to the AI server <NUM> via the network <NUM>. Although the wireless devices 100a to 100f may communicate with each other through the BSs <NUM>/network <NUM>, the wireless devices 100a to 100f may perform direct communication (e.g., sidelink communication) with each other without intervention of the BSs/network. For example, the vehicles 100b-<NUM> and 100b-<NUM> may perform direct communication (e.g. V2V/vehicle-to-everything (V2X) communication).

Wireless communication/connections 150a, 150b, and 150c may be established between the wireless devices 100a to 100fBS <NUM> and between the BSs <NUM>. Herein, the wireless communication/connections may be established through various RATs (e.g., <NUM> NR) such as UL/DL communication 150a, sidelink communication 150b (or, D2D communication), or inter-BS communication (e.g. relay or integrated access backhaul (IAB)). Wireless signals may be transmitted and received between the wireless devices, between the wireless devices and the BSs, and between the BSs through the wireless communication/connections 150a, 150b, and 150c. For example, signals may be transmitted and receive don various physical channels through the wireless communication/connections 150a, 150b and 150c. To this end, at least a part of various configuration information configuring processes, various signal processing processes (e.g., channel encoding/decoding, modulation/demodulation, and resource mapping/demapping), and resource allocation processes, for transmitting/receiving wireless signals, may be performed based on the various proposals of the present disclosure.

Referring to <FIG>, a first wireless device <NUM> and a second wireless device <NUM> may transmit wireless signals through a variety of RATs (e.g., LTE and NR). {The first wireless device <NUM> and the second wireless device <NUM>} may correspond to {the wireless device 100x and the BS <NUM>} and/or {the wireless device 100x and the wireless device 100x} of <FIG>.

The first wireless device <NUM> may include one or more processors <NUM> and one or more memories <NUM>, and further include one or more transceivers <NUM> and/or one or more antennas <NUM>. The processor(s) <NUM> may control the memory(s) <NUM> and/or the transceiver(s) <NUM> and may be configured to implement the descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document. For example, the processor(s) <NUM> may process information in the memory(s) <NUM> to generate first information/signals and then transmit wireless signals including the first information/signals through the transceiver(s) <NUM>. The processor(s) <NUM> may receive wireless signals including second information/signals through the transceiver(s) <NUM> and then store information obtained by processing the second information/signals in the memory(s) <NUM>. The memory(s) <NUM> may be connected to the processor(s) <NUM> and may store various pieces of information related to operations of the processor(s) <NUM>. For example, the memory(s) <NUM> may store software code including instructions for performing all or a part of processes controlled by the processor(s) <NUM> or for performing the descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document. The processor(s) <NUM> and the memory(s) <NUM> may be a part of a communication modem/circuit/chip designed to implement RAT (e.g., LTE or NR). The transceiver(s) <NUM> may be connected to the processor(s) <NUM> and transmit and/or receive wireless signals through the one or more antennas <NUM>. The transceiver(s) <NUM> may be interchangeably used with radio frequency (RF) unit(s). In the present disclosure, the wireless device may be a communication modem/circuit/chip.

The second wireless device <NUM> may include one or more processors <NUM> and one or more memories <NUM>, and further include one or more transceivers <NUM> and/or one or more antennas <NUM>. The processor(s) <NUM> may control the memory(s) <NUM> and/or the transceiver(s) <NUM> and may be configured to implement the descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document. For example, the processor(s) <NUM> may process information in the memory(s) <NUM> to generate third information/signals and then transmit wireless signals including the third information/signals through the transceiver(s) <NUM>. The processor(s) <NUM> may receive wireless signals including fourth information/signals through the transceiver(s) <NUM> and then store information obtained by processing the fourth information/signals in the memory(s) <NUM>. The memory(s) <NUM> may be connected to the processor(s) <NUM> and store various pieces of information related to operations of the processor(s) <NUM>. For example, the memory(s) <NUM> may store software code including instructions for performing all or a part of processes controlled by the processor(s) <NUM> or for performing the descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document. The processor(s) <NUM> and the memory(s) <NUM> may be a part of a communication modem/circuit/chip designed to implement RAT (e.g., LTE or NR). The transceiver(s) <NUM> may be connected to the processor(s) <NUM> and transmit and/or receive wireless signals through the one or more antennas <NUM>. In the present disclosure, the wireless device may be a communication modem/circuit/chip.

Now, hardware elements of the wireless devices <NUM> and <NUM> will be described in greater detail. One or more protocol layers may be implemented by, not limited to, one or more processors <NUM> and <NUM>. For example, the one or more processors <NUM> and <NUM> may implement one or more layers (e.g., functional layers such as physical (PHY), medium access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), RRC, and service data adaptation protocol (SDAP)). The one or more processors <NUM> and <NUM> may generate one or more protocol data units (PDUs) and/or one or more service data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document. The one or more processors <NUM> and <NUM> may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document and provide the messages, control information, data, or information to one or more transceivers <NUM> and <NUM>. The one or more processors <NUM> and <NUM> may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document and provide the generated signals to the one or more transceivers <NUM> and <NUM>. The one or more processors <NUM> and <NUM> may receive the signals (e.g., baseband signals) from the one or more transceivers <NUM> and <NUM> and acquire the PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document.

For example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) may be included in the one or more processors <NUM> and <NUM>. The descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document may be implemented using firmware or software, and the firmware or software may be configured to include the modules, procedures, or functions. Firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document may be included in the one or more processors <NUM> and <NUM> or may be stored in the one or more memories <NUM> and <NUM> and executed by the one or more processors <NUM> and <NUM>. The descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document may be implemented using firmware or software in the form of code, an instruction, and/or a set of instructions.

The one or more memories <NUM> and <NUM> may be configured to include read-only memories (ROMs), random access memories (RAMs), electrically erasable programmable read-only memories (EPROMs), flash memories, hard drives, registers, cash memories, computer-readable storage media, and/or combinations thereof.

The one or more transceivers <NUM> and <NUM> may transmit user data, control information, and/or wireless signals/channels, mentioned in the methods and/or operation flowcharts of this document, to one or more other devices. The one or more transceivers <NUM> and <NUM> may receive user data, control information, and/or wireless signals/channels, mentioned in the descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document, from one or more other devices. For example, the one or more transceivers <NUM> and <NUM> may be connected to the one or more processors <NUM> and <NUM> and transmit and receive wireless signals. For example, the one or more processors <NUM> and <NUM> may perform control so that the one or more transceivers <NUM> and <NUM> may transmit user data, control information, or wireless signals to one or more other devices. The one or more processors <NUM> and <NUM> may perform control so that the one or more transceivers <NUM> and <NUM> may receive user data, control information, or wireless signals from one or more other devices. The one or more transceivers <NUM> and <NUM> may be connected to the one or more antennas <NUM> and <NUM> and the one or more transceivers <NUM> and <NUM> may be configured to transmit and receive user data, control information, and/or wireless signals/channels, mentioned in the descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in this document, through the one or more antennas <NUM> and <NUM>. The one or more transceivers <NUM> and <NUM> may convert received wireless signals/channels from RF band signals into baseband signals in order to process received user data, control information, and wireless signals/channels using the one or more processors <NUM> and <NUM>. The one or more transceivers <NUM> and <NUM> may convert the user data, control information, and wireless signals/channels processed using the one or more processors <NUM> and <NUM> from the baseband signals into the RF band signals.

<FIG> illustrates another example of a wireless device applied to the present disclosure. The wireless device may be implemented in various forms according to a use case/service (refer to <FIG>).

Referring to <FIG>, wireless devices <NUM> and <NUM> may correspond to the wireless devices <NUM> and <NUM> of <FIG> and may be configured to include various elements, components, units/portions, and/or modules. The communication unit <NUM> may include a communication circuit <NUM> and transceiver(s) <NUM>. The control unit <NUM> is electrically connected to the communication unit <NUM>, the memory <NUM>, and the additional components <NUM> and provides overall control to the wireless device. For example, the control unit <NUM> may control an electric/mechanical operation of the wireless device based on programs/code/instructions/information stored in the memory unit <NUM>. The control unit <NUM> may transmit the information stored in the memory unit <NUM> to the outside (e.g., other communication devices) via the communication unit <NUM> through a wireless/wired interface or store, in the memory unit <NUM>, information received through the wireless/wired interface from the outside (e.g., other communication devices) via the communication unit <NUM>.

The additional components <NUM> may be configured in various manners according to type of the wireless device. The wireless device may be implemented in the form of, not limited to, the robot (100a of <FIG>), the vehicles (100b-<NUM> and 100b-<NUM> of <FIG>), the XR device (100c of <FIG>), the hand-held device (100d of <FIG>), the home appliance (100e of <FIG>), the IoT device (100f of <FIG>), a digital broadcasting terminal, a hologram device, a public safety device, an MTC device, a medical device, a FinTech device (or a finance device), a security device, a climate/environment device, the AI server/device (<NUM> of <FIG>), the BSs (<NUM> of <FIG>), a network node, or the like. The wireless device may be mobile or fixed according to a use case/service.

In <FIG>, all of the various elements, components, units/portions, and/or modules in the wireless devices <NUM> and <NUM> may be connected to each other through a wired interface or at least a part thereof may be wirelessly connected through the communication unit <NUM>. Each element, component, unit/portion, and/or module in the wireless devices <NUM> and <NUM> may further include one or more elements. For example, the control unit <NUM> may be configured with a set of one or more processors. For example, the control unit <NUM> may be configured with a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphical processing unit, and a memory control processor. In another example, the memory <NUM> may be configured with a RAM, a dynamic RAM (DRAM), a ROM, a flash memory, a volatile memory, a nonvolatile memory, and/or a combination thereof.

<FIG> illustrates a vehicle or an autonomous driving vehicle applied to the present disclosure. The vehicle or autonomous driving vehicle may be implemented as a mobile robot, a car, a train, a manned/unmanned aerial vehicle (AV), a ship, or the like.

Referring to <FIG>, a vehicle or autonomous driving vehicle <NUM> may include an antenna unit <NUM>, a communication unit <NUM>, a control unit <NUM>, a driving unit 140a, a power supply unit 140b, a sensor unit 140c, and an autonomous driving unit 140d.

The control unit <NUM> may perform various operations by controlling elements of the vehicle or the autonomous driving vehicle <NUM>. The control unit <NUM> may include an ECU. The driving unit 140a may enable the vehicle or the autonomous driving vehicle <NUM> to drive on a road. The driving unit 140a may include an engine, a motor, a powertrain, a wheel, a brake, a steering device, and so on. The power supply unit 140b may supply power to the vehicle or the autonomous driving vehicle <NUM> and include a wired/wireless charging circuit, a battery, and so on. The sensor unit 140c may acquire information about a vehicle state, ambient environment information, user information, and so on. The sensor unit 140c may include an inertial measurement unit (IMU) sensor, a collision sensor, a wheel sensor, a speed sensor, a slope sensor, a weight sensor, a heading sensor, a position module, a vehicle forward/backward sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, an illumination sensor, a pedal position sensor, and so on. The autonomous driving unit 140d may implement technology for maintaining a lane on which the vehicle is driving, technology for automatically adjusting speed, such as adaptive cruise control, technology for autonomously driving along a determined path, technology for driving by automatically setting a route if a destination is set, and the like.

For example, the communication unit <NUM> may receive map data, traffic information data, and so on from an external server. The autonomous driving unit 140d may generate an autonomous driving route and a driving plan from the obtained data. The control unit <NUM> may control the driving unit 140a such that the vehicle or autonomous driving vehicle <NUM> may move along the autonomous driving route according to the driving plan (e.g., speed/direction control). During autonomous driving, the communication unit <NUM> may aperiodically/periodically acquire recent traffic information data from the external server and acquire surrounding traffic information data from neighboring vehicles. During autonomous driving, the sensor unit 140c may obtain information about a vehicle state and/or surrounding environment information. The autonomous driving unit 140d may update the autonomous driving route and the driving plan based on the newly obtained data/information. The communication unit <NUM> may transfer information about a vehicle position, the autonomous driving route, and/or the driving plan to the external server. The external server may predict traffic information data using AI technology based on the information collected from vehicles or autonomous driving vehicles and provide the predicted traffic information data to the vehicles or the autonomous driving vehicles.

The embodiments of the present disclosure described above are combinations of elements and features of the present disclosure. The elements or features may be considered selective unless otherwise mentioned. Each element or feature may be practiced without being combined with other elements or features. Further, an embodiment of the present disclosure may be constructed by combining parts of the elements and/or features. Operation orders described in embodiments of the present disclosure may be rearranged. Some constructions of any one embodiment may be included in another embodiment and may be replaced with corresponding constructions of another embodiment. It is obvious to those skilled in the art that claims that are not explicitly cited in each other in the appended claims may be presented in combination as an embodiment of the present disclosure or included as a new claim by a subsequent amendment after the application is filed.

Claim 1:
A method of performing communication by a user equipment, UE, in a wireless communication system, the method comprising:
detecting a downlink control information, DCI, format that includes a search space, SS, set group switching flag value for cells included in a cell group configured for an SS set group switching operation; and
starting physical downlink control channel, PDCCH, monitoring according to SS sets of a first SS set group and stopping PDCCH monitoring according to SS sets of a second SS set group, for the cells in the cell group, at a first slot that is at least P symbols after a last symbol of a PDCCH carrying the DCI format,
wherein the P symbols is determined for the cell group based on a smallest subcarrier spacing, SCS, among configured bandwidth parts, BWPs, in the cell group.